fold-const.c revision 220150
1/* Fold a constant sub-tree into a single node for C-compiler 2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 3 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 4 Free Software Foundation, Inc. 5 6This file is part of GCC. 7 8GCC is free software; you can redistribute it and/or modify it under 9the terms of the GNU General Public License as published by the Free 10Software Foundation; either version 2, or (at your option) any later 11version. 12 13GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14WARRANTY; without even the implied warranty of MERCHANTABILITY or 15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16for more details. 17 18You should have received a copy of the GNU General Public License 19along with GCC; see the file COPYING. If not, write to the Free 20Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 2102110-1301, USA. */ 22 23/*@@ This file should be rewritten to use an arbitrary precision 24 @@ representation for "struct tree_int_cst" and "struct tree_real_cst". 25 @@ Perhaps the routines could also be used for bc/dc, and made a lib. 26 @@ The routines that translate from the ap rep should 27 @@ warn if precision et. al. is lost. 28 @@ This would also make life easier when this technology is used 29 @@ for cross-compilers. */ 30 31/* The entry points in this file are fold, size_int_wide, size_binop 32 and force_fit_type. 33 34 fold takes a tree as argument and returns a simplified tree. 35 36 size_binop takes a tree code for an arithmetic operation 37 and two operands that are trees, and produces a tree for the 38 result, assuming the type comes from `sizetype'. 39 40 size_int takes an integer value, and creates a tree constant 41 with type from `sizetype'. 42 43 force_fit_type takes a constant, an overflowable flag and prior 44 overflow indicators. It forces the value to fit the type and sets 45 TREE_OVERFLOW and TREE_CONSTANT_OVERFLOW as appropriate. */ 46 47#include "config.h" 48#include "system.h" 49#include "coretypes.h" 50#include "tm.h" 51#include "flags.h" 52#include "tree.h" 53#include "real.h" 54#include "rtl.h" 55#include "expr.h" 56#include "tm_p.h" 57#include "toplev.h" 58#include "intl.h" 59#include "ggc.h" 60#include "hashtab.h" 61#include "langhooks.h" 62#include "md5.h" 63 64/* Non-zero if we are folding constants inside an initializer; zero 65 otherwise. */ 66int folding_initializer = 0; 67 68/* The following constants represent a bit based encoding of GCC's 69 comparison operators. This encoding simplifies transformations 70 on relational comparison operators, such as AND and OR. */ 71enum comparison_code { 72 COMPCODE_FALSE = 0, 73 COMPCODE_LT = 1, 74 COMPCODE_EQ = 2, 75 COMPCODE_LE = 3, 76 COMPCODE_GT = 4, 77 COMPCODE_LTGT = 5, 78 COMPCODE_GE = 6, 79 COMPCODE_ORD = 7, 80 COMPCODE_UNORD = 8, 81 COMPCODE_UNLT = 9, 82 COMPCODE_UNEQ = 10, 83 COMPCODE_UNLE = 11, 84 COMPCODE_UNGT = 12, 85 COMPCODE_NE = 13, 86 COMPCODE_UNGE = 14, 87 COMPCODE_TRUE = 15 88}; 89 90static void encode (HOST_WIDE_INT *, unsigned HOST_WIDE_INT, HOST_WIDE_INT); 91static void decode (HOST_WIDE_INT *, unsigned HOST_WIDE_INT *, HOST_WIDE_INT *); 92static bool negate_mathfn_p (enum built_in_function); 93static bool negate_expr_p (tree); 94static tree negate_expr (tree); 95static tree split_tree (tree, enum tree_code, tree *, tree *, tree *, int); 96static tree associate_trees (tree, tree, enum tree_code, tree); 97static tree const_binop (enum tree_code, tree, tree, int); 98static enum comparison_code comparison_to_compcode (enum tree_code); 99static enum tree_code compcode_to_comparison (enum comparison_code); 100static tree combine_comparisons (enum tree_code, enum tree_code, 101 enum tree_code, tree, tree, tree); 102static int truth_value_p (enum tree_code); 103static int operand_equal_for_comparison_p (tree, tree, tree); 104static int twoval_comparison_p (tree, tree *, tree *, int *); 105static tree eval_subst (tree, tree, tree, tree, tree); 106static tree pedantic_omit_one_operand (tree, tree, tree); 107static tree distribute_bit_expr (enum tree_code, tree, tree, tree); 108static tree make_bit_field_ref (tree, tree, int, int, int); 109static tree optimize_bit_field_compare (enum tree_code, tree, tree, tree); 110static tree decode_field_reference (tree, HOST_WIDE_INT *, HOST_WIDE_INT *, 111 enum machine_mode *, int *, int *, 112 tree *, tree *); 113static int all_ones_mask_p (tree, int); 114static tree sign_bit_p (tree, tree); 115static int simple_operand_p (tree); 116static tree range_binop (enum tree_code, tree, tree, int, tree, int); 117static tree range_predecessor (tree); 118static tree range_successor (tree); 119static tree make_range (tree, int *, tree *, tree *, bool *); 120static tree build_range_check (tree, tree, int, tree, tree); 121static int merge_ranges (int *, tree *, tree *, int, tree, tree, int, tree, 122 tree); 123static tree fold_range_test (enum tree_code, tree, tree, tree); 124static tree fold_cond_expr_with_comparison (tree, tree, tree, tree); 125static tree unextend (tree, int, int, tree); 126static tree fold_truthop (enum tree_code, tree, tree, tree); 127static tree optimize_minmax_comparison (enum tree_code, tree, tree, tree); 128static tree extract_muldiv (tree, tree, enum tree_code, tree, bool *); 129static tree extract_muldiv_1 (tree, tree, enum tree_code, tree, bool *); 130static int multiple_of_p (tree, tree, tree); 131static tree fold_binary_op_with_conditional_arg (enum tree_code, tree, 132 tree, tree, 133 tree, tree, int); 134static bool fold_real_zero_addition_p (tree, tree, int); 135static tree fold_mathfn_compare (enum built_in_function, enum tree_code, 136 tree, tree, tree); 137static tree fold_inf_compare (enum tree_code, tree, tree, tree); 138static tree fold_div_compare (enum tree_code, tree, tree, tree); 139static bool reorder_operands_p (tree, tree); 140static tree fold_negate_const (tree, tree); 141static tree fold_not_const (tree, tree); 142static tree fold_relational_const (enum tree_code, tree, tree, tree); 143static int native_encode_expr (tree, unsigned char *, int); 144static tree native_interpret_expr (tree, unsigned char *, int); 145 146 147/* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring 148 overflow. Suppose A, B and SUM have the same respective signs as A1, B1, 149 and SUM1. Then this yields nonzero if overflow occurred during the 150 addition. 151 152 Overflow occurs if A and B have the same sign, but A and SUM differ in 153 sign. Use `^' to test whether signs differ, and `< 0' to isolate the 154 sign. */ 155#define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0) 156 157/* To do constant folding on INTEGER_CST nodes requires two-word arithmetic. 158 We do that by representing the two-word integer in 4 words, with only 159 HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive 160 number. The value of the word is LOWPART + HIGHPART * BASE. */ 161 162#define LOWPART(x) \ 163 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1)) 164#define HIGHPART(x) \ 165 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2) 166#define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2) 167 168/* Unpack a two-word integer into 4 words. 169 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces. 170 WORDS points to the array of HOST_WIDE_INTs. */ 171 172static void 173encode (HOST_WIDE_INT *words, unsigned HOST_WIDE_INT low, HOST_WIDE_INT hi) 174{ 175 words[0] = LOWPART (low); 176 words[1] = HIGHPART (low); 177 words[2] = LOWPART (hi); 178 words[3] = HIGHPART (hi); 179} 180 181/* Pack an array of 4 words into a two-word integer. 182 WORDS points to the array of words. 183 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */ 184 185static void 186decode (HOST_WIDE_INT *words, unsigned HOST_WIDE_INT *low, 187 HOST_WIDE_INT *hi) 188{ 189 *low = words[0] + words[1] * BASE; 190 *hi = words[2] + words[3] * BASE; 191} 192 193/* T is an INT_CST node. OVERFLOWABLE indicates if we are interested 194 in overflow of the value, when >0 we are only interested in signed 195 overflow, for <0 we are interested in any overflow. OVERFLOWED 196 indicates whether overflow has already occurred. CONST_OVERFLOWED 197 indicates whether constant overflow has already occurred. We force 198 T's value to be within range of T's type (by setting to 0 or 1 all 199 the bits outside the type's range). We set TREE_OVERFLOWED if, 200 OVERFLOWED is nonzero, 201 or OVERFLOWABLE is >0 and signed overflow occurs 202 or OVERFLOWABLE is <0 and any overflow occurs 203 We set TREE_CONSTANT_OVERFLOWED if, 204 CONST_OVERFLOWED is nonzero 205 or we set TREE_OVERFLOWED. 206 We return either the original T, or a copy. */ 207 208tree 209force_fit_type (tree t, int overflowable, 210 bool overflowed, bool overflowed_const) 211{ 212 unsigned HOST_WIDE_INT low; 213 HOST_WIDE_INT high; 214 unsigned int prec; 215 int sign_extended_type; 216 217 gcc_assert (TREE_CODE (t) == INTEGER_CST); 218 219 low = TREE_INT_CST_LOW (t); 220 high = TREE_INT_CST_HIGH (t); 221 222 if (POINTER_TYPE_P (TREE_TYPE (t)) 223 || TREE_CODE (TREE_TYPE (t)) == OFFSET_TYPE) 224 prec = POINTER_SIZE; 225 else 226 prec = TYPE_PRECISION (TREE_TYPE (t)); 227 /* Size types *are* sign extended. */ 228 sign_extended_type = (!TYPE_UNSIGNED (TREE_TYPE (t)) 229 || (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE 230 && TYPE_IS_SIZETYPE (TREE_TYPE (t)))); 231 232 /* First clear all bits that are beyond the type's precision. */ 233 234 if (prec >= 2 * HOST_BITS_PER_WIDE_INT) 235 ; 236 else if (prec > HOST_BITS_PER_WIDE_INT) 237 high &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT)); 238 else 239 { 240 high = 0; 241 if (prec < HOST_BITS_PER_WIDE_INT) 242 low &= ~((HOST_WIDE_INT) (-1) << prec); 243 } 244 245 if (!sign_extended_type) 246 /* No sign extension */; 247 else if (prec >= 2 * HOST_BITS_PER_WIDE_INT) 248 /* Correct width already. */; 249 else if (prec > HOST_BITS_PER_WIDE_INT) 250 { 251 /* Sign extend top half? */ 252 if (high & ((unsigned HOST_WIDE_INT)1 253 << (prec - HOST_BITS_PER_WIDE_INT - 1))) 254 high |= (HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT); 255 } 256 else if (prec == HOST_BITS_PER_WIDE_INT) 257 { 258 if ((HOST_WIDE_INT)low < 0) 259 high = -1; 260 } 261 else 262 { 263 /* Sign extend bottom half? */ 264 if (low & ((unsigned HOST_WIDE_INT)1 << (prec - 1))) 265 { 266 high = -1; 267 low |= (HOST_WIDE_INT)(-1) << prec; 268 } 269 } 270 271 /* If the value changed, return a new node. */ 272 if (overflowed || overflowed_const 273 || low != TREE_INT_CST_LOW (t) || high != TREE_INT_CST_HIGH (t)) 274 { 275 t = build_int_cst_wide (TREE_TYPE (t), low, high); 276 277 if (overflowed 278 || overflowable < 0 279 || (overflowable > 0 && sign_extended_type)) 280 { 281 t = copy_node (t); 282 TREE_OVERFLOW (t) = 1; 283 TREE_CONSTANT_OVERFLOW (t) = 1; 284 } 285 else if (overflowed_const) 286 { 287 t = copy_node (t); 288 TREE_CONSTANT_OVERFLOW (t) = 1; 289 } 290 } 291 292 return t; 293} 294 295/* Add two doubleword integers with doubleword result. 296 Return nonzero if the operation overflows according to UNSIGNED_P. 297 Each argument is given as two `HOST_WIDE_INT' pieces. 298 One argument is L1 and H1; the other, L2 and H2. 299 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */ 300 301int 302add_double_with_sign (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1, 303 unsigned HOST_WIDE_INT l2, HOST_WIDE_INT h2, 304 unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv, 305 bool unsigned_p) 306{ 307 unsigned HOST_WIDE_INT l; 308 HOST_WIDE_INT h; 309 310 l = l1 + l2; 311 h = h1 + h2 + (l < l1); 312 313 *lv = l; 314 *hv = h; 315 316 if (unsigned_p) 317 return (unsigned HOST_WIDE_INT) h < (unsigned HOST_WIDE_INT) h1; 318 else 319 return OVERFLOW_SUM_SIGN (h1, h2, h); 320} 321 322/* Negate a doubleword integer with doubleword result. 323 Return nonzero if the operation overflows, assuming it's signed. 324 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1. 325 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */ 326 327int 328neg_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1, 329 unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv) 330{ 331 if (l1 == 0) 332 { 333 *lv = 0; 334 *hv = - h1; 335 return (*hv & h1) < 0; 336 } 337 else 338 { 339 *lv = -l1; 340 *hv = ~h1; 341 return 0; 342 } 343} 344 345/* Multiply two doubleword integers with doubleword result. 346 Return nonzero if the operation overflows according to UNSIGNED_P. 347 Each argument is given as two `HOST_WIDE_INT' pieces. 348 One argument is L1 and H1; the other, L2 and H2. 349 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */ 350 351int 352mul_double_with_sign (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1, 353 unsigned HOST_WIDE_INT l2, HOST_WIDE_INT h2, 354 unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv, 355 bool unsigned_p) 356{ 357 HOST_WIDE_INT arg1[4]; 358 HOST_WIDE_INT arg2[4]; 359 HOST_WIDE_INT prod[4 * 2]; 360 unsigned HOST_WIDE_INT carry; 361 int i, j, k; 362 unsigned HOST_WIDE_INT toplow, neglow; 363 HOST_WIDE_INT tophigh, neghigh; 364 365 encode (arg1, l1, h1); 366 encode (arg2, l2, h2); 367 368 memset (prod, 0, sizeof prod); 369 370 for (i = 0; i < 4; i++) 371 { 372 carry = 0; 373 for (j = 0; j < 4; j++) 374 { 375 k = i + j; 376 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */ 377 carry += arg1[i] * arg2[j]; 378 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */ 379 carry += prod[k]; 380 prod[k] = LOWPART (carry); 381 carry = HIGHPART (carry); 382 } 383 prod[i + 4] = carry; 384 } 385 386 decode (prod, lv, hv); 387 decode (prod + 4, &toplow, &tophigh); 388 389 /* Unsigned overflow is immediate. */ 390 if (unsigned_p) 391 return (toplow | tophigh) != 0; 392 393 /* Check for signed overflow by calculating the signed representation of the 394 top half of the result; it should agree with the low half's sign bit. */ 395 if (h1 < 0) 396 { 397 neg_double (l2, h2, &neglow, &neghigh); 398 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh); 399 } 400 if (h2 < 0) 401 { 402 neg_double (l1, h1, &neglow, &neghigh); 403 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh); 404 } 405 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0; 406} 407 408/* Shift the doubleword integer in L1, H1 left by COUNT places 409 keeping only PREC bits of result. 410 Shift right if COUNT is negative. 411 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift. 412 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ 413 414void 415lshift_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1, 416 HOST_WIDE_INT count, unsigned int prec, 417 unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv, int arith) 418{ 419 unsigned HOST_WIDE_INT signmask; 420 421 if (count < 0) 422 { 423 rshift_double (l1, h1, -count, prec, lv, hv, arith); 424 return; 425 } 426 427 if (SHIFT_COUNT_TRUNCATED) 428 count %= prec; 429 430 if (count >= 2 * HOST_BITS_PER_WIDE_INT) 431 { 432 /* Shifting by the host word size is undefined according to the 433 ANSI standard, so we must handle this as a special case. */ 434 *hv = 0; 435 *lv = 0; 436 } 437 else if (count >= HOST_BITS_PER_WIDE_INT) 438 { 439 *hv = l1 << (count - HOST_BITS_PER_WIDE_INT); 440 *lv = 0; 441 } 442 else 443 { 444 *hv = (((unsigned HOST_WIDE_INT) h1 << count) 445 | (l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1)); 446 *lv = l1 << count; 447 } 448 449 /* Sign extend all bits that are beyond the precision. */ 450 451 signmask = -((prec > HOST_BITS_PER_WIDE_INT 452 ? ((unsigned HOST_WIDE_INT) *hv 453 >> (prec - HOST_BITS_PER_WIDE_INT - 1)) 454 : (*lv >> (prec - 1))) & 1); 455 456 if (prec >= 2 * HOST_BITS_PER_WIDE_INT) 457 ; 458 else if (prec >= HOST_BITS_PER_WIDE_INT) 459 { 460 *hv &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT)); 461 *hv |= signmask << (prec - HOST_BITS_PER_WIDE_INT); 462 } 463 else 464 { 465 *hv = signmask; 466 *lv &= ~((unsigned HOST_WIDE_INT) (-1) << prec); 467 *lv |= signmask << prec; 468 } 469} 470 471/* Shift the doubleword integer in L1, H1 right by COUNT places 472 keeping only PREC bits of result. COUNT must be positive. 473 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift. 474 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ 475 476void 477rshift_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1, 478 HOST_WIDE_INT count, unsigned int prec, 479 unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv, 480 int arith) 481{ 482 unsigned HOST_WIDE_INT signmask; 483 484 signmask = (arith 485 ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1)) 486 : 0); 487 488 if (SHIFT_COUNT_TRUNCATED) 489 count %= prec; 490 491 if (count >= 2 * HOST_BITS_PER_WIDE_INT) 492 { 493 /* Shifting by the host word size is undefined according to the 494 ANSI standard, so we must handle this as a special case. */ 495 *hv = 0; 496 *lv = 0; 497 } 498 else if (count >= HOST_BITS_PER_WIDE_INT) 499 { 500 *hv = 0; 501 *lv = (unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT); 502 } 503 else 504 { 505 *hv = (unsigned HOST_WIDE_INT) h1 >> count; 506 *lv = ((l1 >> count) 507 | ((unsigned HOST_WIDE_INT) h1 << (HOST_BITS_PER_WIDE_INT - count - 1) << 1)); 508 } 509 510 /* Zero / sign extend all bits that are beyond the precision. */ 511 512 if (count >= (HOST_WIDE_INT)prec) 513 { 514 *hv = signmask; 515 *lv = signmask; 516 } 517 else if ((prec - count) >= 2 * HOST_BITS_PER_WIDE_INT) 518 ; 519 else if ((prec - count) >= HOST_BITS_PER_WIDE_INT) 520 { 521 *hv &= ~((HOST_WIDE_INT) (-1) << (prec - count - HOST_BITS_PER_WIDE_INT)); 522 *hv |= signmask << (prec - count - HOST_BITS_PER_WIDE_INT); 523 } 524 else 525 { 526 *hv = signmask; 527 *lv &= ~((unsigned HOST_WIDE_INT) (-1) << (prec - count)); 528 *lv |= signmask << (prec - count); 529 } 530} 531 532/* Rotate the doubleword integer in L1, H1 left by COUNT places 533 keeping only PREC bits of result. 534 Rotate right if COUNT is negative. 535 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ 536 537void 538lrotate_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1, 539 HOST_WIDE_INT count, unsigned int prec, 540 unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv) 541{ 542 unsigned HOST_WIDE_INT s1l, s2l; 543 HOST_WIDE_INT s1h, s2h; 544 545 count %= prec; 546 if (count < 0) 547 count += prec; 548 549 lshift_double (l1, h1, count, prec, &s1l, &s1h, 0); 550 rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0); 551 *lv = s1l | s2l; 552 *hv = s1h | s2h; 553} 554 555/* Rotate the doubleword integer in L1, H1 left by COUNT places 556 keeping only PREC bits of result. COUNT must be positive. 557 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ 558 559void 560rrotate_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1, 561 HOST_WIDE_INT count, unsigned int prec, 562 unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv) 563{ 564 unsigned HOST_WIDE_INT s1l, s2l; 565 HOST_WIDE_INT s1h, s2h; 566 567 count %= prec; 568 if (count < 0) 569 count += prec; 570 571 rshift_double (l1, h1, count, prec, &s1l, &s1h, 0); 572 lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0); 573 *lv = s1l | s2l; 574 *hv = s1h | s2h; 575} 576 577/* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN 578 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM). 579 CODE is a tree code for a kind of division, one of 580 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR 581 or EXACT_DIV_EXPR 582 It controls how the quotient is rounded to an integer. 583 Return nonzero if the operation overflows. 584 UNS nonzero says do unsigned division. */ 585 586int 587div_and_round_double (enum tree_code code, int uns, 588 unsigned HOST_WIDE_INT lnum_orig, /* num == numerator == dividend */ 589 HOST_WIDE_INT hnum_orig, 590 unsigned HOST_WIDE_INT lden_orig, /* den == denominator == divisor */ 591 HOST_WIDE_INT hden_orig, 592 unsigned HOST_WIDE_INT *lquo, 593 HOST_WIDE_INT *hquo, unsigned HOST_WIDE_INT *lrem, 594 HOST_WIDE_INT *hrem) 595{ 596 int quo_neg = 0; 597 HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */ 598 HOST_WIDE_INT den[4], quo[4]; 599 int i, j; 600 unsigned HOST_WIDE_INT work; 601 unsigned HOST_WIDE_INT carry = 0; 602 unsigned HOST_WIDE_INT lnum = lnum_orig; 603 HOST_WIDE_INT hnum = hnum_orig; 604 unsigned HOST_WIDE_INT lden = lden_orig; 605 HOST_WIDE_INT hden = hden_orig; 606 int overflow = 0; 607 608 if (hden == 0 && lden == 0) 609 overflow = 1, lden = 1; 610 611 /* Calculate quotient sign and convert operands to unsigned. */ 612 if (!uns) 613 { 614 if (hnum < 0) 615 { 616 quo_neg = ~ quo_neg; 617 /* (minimum integer) / (-1) is the only overflow case. */ 618 if (neg_double (lnum, hnum, &lnum, &hnum) 619 && ((HOST_WIDE_INT) lden & hden) == -1) 620 overflow = 1; 621 } 622 if (hden < 0) 623 { 624 quo_neg = ~ quo_neg; 625 neg_double (lden, hden, &lden, &hden); 626 } 627 } 628 629 if (hnum == 0 && hden == 0) 630 { /* single precision */ 631 *hquo = *hrem = 0; 632 /* This unsigned division rounds toward zero. */ 633 *lquo = lnum / lden; 634 goto finish_up; 635 } 636 637 if (hnum == 0) 638 { /* trivial case: dividend < divisor */ 639 /* hden != 0 already checked. */ 640 *hquo = *lquo = 0; 641 *hrem = hnum; 642 *lrem = lnum; 643 goto finish_up; 644 } 645 646 memset (quo, 0, sizeof quo); 647 648 memset (num, 0, sizeof num); /* to zero 9th element */ 649 memset (den, 0, sizeof den); 650 651 encode (num, lnum, hnum); 652 encode (den, lden, hden); 653 654 /* Special code for when the divisor < BASE. */ 655 if (hden == 0 && lden < (unsigned HOST_WIDE_INT) BASE) 656 { 657 /* hnum != 0 already checked. */ 658 for (i = 4 - 1; i >= 0; i--) 659 { 660 work = num[i] + carry * BASE; 661 quo[i] = work / lden; 662 carry = work % lden; 663 } 664 } 665 else 666 { 667 /* Full double precision division, 668 with thanks to Don Knuth's "Seminumerical Algorithms". */ 669 int num_hi_sig, den_hi_sig; 670 unsigned HOST_WIDE_INT quo_est, scale; 671 672 /* Find the highest nonzero divisor digit. */ 673 for (i = 4 - 1;; i--) 674 if (den[i] != 0) 675 { 676 den_hi_sig = i; 677 break; 678 } 679 680 /* Insure that the first digit of the divisor is at least BASE/2. 681 This is required by the quotient digit estimation algorithm. */ 682 683 scale = BASE / (den[den_hi_sig] + 1); 684 if (scale > 1) 685 { /* scale divisor and dividend */ 686 carry = 0; 687 for (i = 0; i <= 4 - 1; i++) 688 { 689 work = (num[i] * scale) + carry; 690 num[i] = LOWPART (work); 691 carry = HIGHPART (work); 692 } 693 694 num[4] = carry; 695 carry = 0; 696 for (i = 0; i <= 4 - 1; i++) 697 { 698 work = (den[i] * scale) + carry; 699 den[i] = LOWPART (work); 700 carry = HIGHPART (work); 701 if (den[i] != 0) den_hi_sig = i; 702 } 703 } 704 705 num_hi_sig = 4; 706 707 /* Main loop */ 708 for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--) 709 { 710 /* Guess the next quotient digit, quo_est, by dividing the first 711 two remaining dividend digits by the high order quotient digit. 712 quo_est is never low and is at most 2 high. */ 713 unsigned HOST_WIDE_INT tmp; 714 715 num_hi_sig = i + den_hi_sig + 1; 716 work = num[num_hi_sig] * BASE + num[num_hi_sig - 1]; 717 if (num[num_hi_sig] != den[den_hi_sig]) 718 quo_est = work / den[den_hi_sig]; 719 else 720 quo_est = BASE - 1; 721 722 /* Refine quo_est so it's usually correct, and at most one high. */ 723 tmp = work - quo_est * den[den_hi_sig]; 724 if (tmp < BASE 725 && (den[den_hi_sig - 1] * quo_est 726 > (tmp * BASE + num[num_hi_sig - 2]))) 727 quo_est--; 728 729 /* Try QUO_EST as the quotient digit, by multiplying the 730 divisor by QUO_EST and subtracting from the remaining dividend. 731 Keep in mind that QUO_EST is the I - 1st digit. */ 732 733 carry = 0; 734 for (j = 0; j <= den_hi_sig; j++) 735 { 736 work = quo_est * den[j] + carry; 737 carry = HIGHPART (work); 738 work = num[i + j] - LOWPART (work); 739 num[i + j] = LOWPART (work); 740 carry += HIGHPART (work) != 0; 741 } 742 743 /* If quo_est was high by one, then num[i] went negative and 744 we need to correct things. */ 745 if (num[num_hi_sig] < (HOST_WIDE_INT) carry) 746 { 747 quo_est--; 748 carry = 0; /* add divisor back in */ 749 for (j = 0; j <= den_hi_sig; j++) 750 { 751 work = num[i + j] + den[j] + carry; 752 carry = HIGHPART (work); 753 num[i + j] = LOWPART (work); 754 } 755 756 num [num_hi_sig] += carry; 757 } 758 759 /* Store the quotient digit. */ 760 quo[i] = quo_est; 761 } 762 } 763 764 decode (quo, lquo, hquo); 765 766 finish_up: 767 /* If result is negative, make it so. */ 768 if (quo_neg) 769 neg_double (*lquo, *hquo, lquo, hquo); 770 771 /* Compute trial remainder: rem = num - (quo * den) */ 772 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem); 773 neg_double (*lrem, *hrem, lrem, hrem); 774 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem); 775 776 switch (code) 777 { 778 case TRUNC_DIV_EXPR: 779 case TRUNC_MOD_EXPR: /* round toward zero */ 780 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */ 781 return overflow; 782 783 case FLOOR_DIV_EXPR: 784 case FLOOR_MOD_EXPR: /* round toward negative infinity */ 785 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */ 786 { 787 /* quo = quo - 1; */ 788 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, 789 lquo, hquo); 790 } 791 else 792 return overflow; 793 break; 794 795 case CEIL_DIV_EXPR: 796 case CEIL_MOD_EXPR: /* round toward positive infinity */ 797 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */ 798 { 799 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0, 800 lquo, hquo); 801 } 802 else 803 return overflow; 804 break; 805 806 case ROUND_DIV_EXPR: 807 case ROUND_MOD_EXPR: /* round to closest integer */ 808 { 809 unsigned HOST_WIDE_INT labs_rem = *lrem; 810 HOST_WIDE_INT habs_rem = *hrem; 811 unsigned HOST_WIDE_INT labs_den = lden, ltwice; 812 HOST_WIDE_INT habs_den = hden, htwice; 813 814 /* Get absolute values. */ 815 if (*hrem < 0) 816 neg_double (*lrem, *hrem, &labs_rem, &habs_rem); 817 if (hden < 0) 818 neg_double (lden, hden, &labs_den, &habs_den); 819 820 /* If (2 * abs (lrem) >= abs (lden)) */ 821 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0, 822 labs_rem, habs_rem, <wice, &htwice); 823 824 if (((unsigned HOST_WIDE_INT) habs_den 825 < (unsigned HOST_WIDE_INT) htwice) 826 || (((unsigned HOST_WIDE_INT) habs_den 827 == (unsigned HOST_WIDE_INT) htwice) 828 && (labs_den < ltwice))) 829 { 830 if (*hquo < 0) 831 /* quo = quo - 1; */ 832 add_double (*lquo, *hquo, 833 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo); 834 else 835 /* quo = quo + 1; */ 836 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0, 837 lquo, hquo); 838 } 839 else 840 return overflow; 841 } 842 break; 843 844 default: 845 gcc_unreachable (); 846 } 847 848 /* Compute true remainder: rem = num - (quo * den) */ 849 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem); 850 neg_double (*lrem, *hrem, lrem, hrem); 851 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem); 852 return overflow; 853} 854 855/* If ARG2 divides ARG1 with zero remainder, carries out the division 856 of type CODE and returns the quotient. 857 Otherwise returns NULL_TREE. */ 858 859static tree 860div_if_zero_remainder (enum tree_code code, tree arg1, tree arg2) 861{ 862 unsigned HOST_WIDE_INT int1l, int2l; 863 HOST_WIDE_INT int1h, int2h; 864 unsigned HOST_WIDE_INT quol, reml; 865 HOST_WIDE_INT quoh, remh; 866 tree type = TREE_TYPE (arg1); 867 int uns = TYPE_UNSIGNED (type); 868 869 int1l = TREE_INT_CST_LOW (arg1); 870 int1h = TREE_INT_CST_HIGH (arg1); 871 int2l = TREE_INT_CST_LOW (arg2); 872 int2h = TREE_INT_CST_HIGH (arg2); 873 874 div_and_round_double (code, uns, int1l, int1h, int2l, int2h, 875 &quol, &quoh, &reml, &remh); 876 if (remh != 0 || reml != 0) 877 return NULL_TREE; 878 879 return build_int_cst_wide (type, quol, quoh); 880} 881 882/* This is non-zero if we should defer warnings about undefined 883 overflow. This facility exists because these warnings are a 884 special case. The code to estimate loop iterations does not want 885 to issue any warnings, since it works with expressions which do not 886 occur in user code. Various bits of cleanup code call fold(), but 887 only use the result if it has certain characteristics (e.g., is a 888 constant); that code only wants to issue a warning if the result is 889 used. */ 890 891static int fold_deferring_overflow_warnings; 892 893/* If a warning about undefined overflow is deferred, this is the 894 warning. Note that this may cause us to turn two warnings into 895 one, but that is fine since it is sufficient to only give one 896 warning per expression. */ 897 898static const char* fold_deferred_overflow_warning; 899 900/* If a warning about undefined overflow is deferred, this is the 901 level at which the warning should be emitted. */ 902 903static enum warn_strict_overflow_code fold_deferred_overflow_code; 904 905/* Start deferring overflow warnings. We could use a stack here to 906 permit nested calls, but at present it is not necessary. */ 907 908void 909fold_defer_overflow_warnings (void) 910{ 911 ++fold_deferring_overflow_warnings; 912} 913 914/* Stop deferring overflow warnings. If there is a pending warning, 915 and ISSUE is true, then issue the warning if appropriate. STMT is 916 the statement with which the warning should be associated (used for 917 location information); STMT may be NULL. CODE is the level of the 918 warning--a warn_strict_overflow_code value. This function will use 919 the smaller of CODE and the deferred code when deciding whether to 920 issue the warning. CODE may be zero to mean to always use the 921 deferred code. */ 922 923void 924fold_undefer_overflow_warnings (bool issue, tree stmt, int code) 925{ 926 const char *warnmsg; 927 location_t locus; 928 929 gcc_assert (fold_deferring_overflow_warnings > 0); 930 --fold_deferring_overflow_warnings; 931 if (fold_deferring_overflow_warnings > 0) 932 { 933 if (fold_deferred_overflow_warning != NULL 934 && code != 0 935 && code < (int) fold_deferred_overflow_code) 936 fold_deferred_overflow_code = code; 937 return; 938 } 939 940 warnmsg = fold_deferred_overflow_warning; 941 fold_deferred_overflow_warning = NULL; 942 943 if (!issue || warnmsg == NULL) 944 return; 945 946 /* Use the smallest code level when deciding to issue the 947 warning. */ 948 if (code == 0 || code > (int) fold_deferred_overflow_code) 949 code = fold_deferred_overflow_code; 950 951 if (!issue_strict_overflow_warning (code)) 952 return; 953 954 if (stmt == NULL_TREE || !EXPR_HAS_LOCATION (stmt)) 955 locus = input_location; 956 else 957 locus = EXPR_LOCATION (stmt); 958 warning (OPT_Wstrict_overflow, "%H%s", &locus, warnmsg); 959} 960 961/* Stop deferring overflow warnings, ignoring any deferred 962 warnings. */ 963 964void 965fold_undefer_and_ignore_overflow_warnings (void) 966{ 967 fold_undefer_overflow_warnings (false, NULL_TREE, 0); 968} 969 970/* Whether we are deferring overflow warnings. */ 971 972bool 973fold_deferring_overflow_warnings_p (void) 974{ 975 return fold_deferring_overflow_warnings > 0; 976} 977 978/* This is called when we fold something based on the fact that signed 979 overflow is undefined. */ 980 981static void 982fold_overflow_warning (const char* gmsgid, enum warn_strict_overflow_code wc) 983{ 984 gcc_assert (!flag_wrapv && !flag_trapv); 985 if (fold_deferring_overflow_warnings > 0) 986 { 987 if (fold_deferred_overflow_warning == NULL 988 || wc < fold_deferred_overflow_code) 989 { 990 fold_deferred_overflow_warning = gmsgid; 991 fold_deferred_overflow_code = wc; 992 } 993 } 994 else if (issue_strict_overflow_warning (wc)) 995 warning (OPT_Wstrict_overflow, gmsgid); 996} 997 998/* Return true if the built-in mathematical function specified by CODE 999 is odd, i.e. -f(x) == f(-x). */ 1000 1001static bool 1002negate_mathfn_p (enum built_in_function code) 1003{ 1004 switch (code) 1005 { 1006 CASE_FLT_FN (BUILT_IN_ASIN): 1007 CASE_FLT_FN (BUILT_IN_ASINH): 1008 CASE_FLT_FN (BUILT_IN_ATAN): 1009 CASE_FLT_FN (BUILT_IN_ATANH): 1010 CASE_FLT_FN (BUILT_IN_CBRT): 1011 CASE_FLT_FN (BUILT_IN_SIN): 1012 CASE_FLT_FN (BUILT_IN_SINH): 1013 CASE_FLT_FN (BUILT_IN_TAN): 1014 CASE_FLT_FN (BUILT_IN_TANH): 1015 return true; 1016 1017 default: 1018 break; 1019 } 1020 return false; 1021} 1022 1023/* Check whether we may negate an integer constant T without causing 1024 overflow. */ 1025 1026bool 1027may_negate_without_overflow_p (tree t) 1028{ 1029 unsigned HOST_WIDE_INT val; 1030 unsigned int prec; 1031 tree type; 1032 1033 gcc_assert (TREE_CODE (t) == INTEGER_CST); 1034 1035 type = TREE_TYPE (t); 1036 if (TYPE_UNSIGNED (type)) 1037 return false; 1038 1039 prec = TYPE_PRECISION (type); 1040 if (prec > HOST_BITS_PER_WIDE_INT) 1041 { 1042 if (TREE_INT_CST_LOW (t) != 0) 1043 return true; 1044 prec -= HOST_BITS_PER_WIDE_INT; 1045 val = TREE_INT_CST_HIGH (t); 1046 } 1047 else 1048 val = TREE_INT_CST_LOW (t); 1049 if (prec < HOST_BITS_PER_WIDE_INT) 1050 val &= ((unsigned HOST_WIDE_INT) 1 << prec) - 1; 1051 return val != ((unsigned HOST_WIDE_INT) 1 << (prec - 1)); 1052} 1053 1054/* Determine whether an expression T can be cheaply negated using 1055 the function negate_expr without introducing undefined overflow. */ 1056 1057static bool 1058negate_expr_p (tree t) 1059{ 1060 tree type; 1061 1062 if (t == 0) 1063 return false; 1064 1065 type = TREE_TYPE (t); 1066 1067 STRIP_SIGN_NOPS (t); 1068 switch (TREE_CODE (t)) 1069 { 1070 case INTEGER_CST: 1071 if (TYPE_OVERFLOW_WRAPS (type)) 1072 return true; 1073 1074 /* Check that -CST will not overflow type. */ 1075 return may_negate_without_overflow_p (t); 1076 case BIT_NOT_EXPR: 1077 return (INTEGRAL_TYPE_P (type) 1078 && TYPE_OVERFLOW_WRAPS (type)); 1079 1080 case REAL_CST: 1081 case NEGATE_EXPR: 1082 return true; 1083 1084 case COMPLEX_CST: 1085 return negate_expr_p (TREE_REALPART (t)) 1086 && negate_expr_p (TREE_IMAGPART (t)); 1087 1088 case PLUS_EXPR: 1089 if (FLOAT_TYPE_P (type) && !flag_unsafe_math_optimizations) 1090 return false; 1091 /* -(A + B) -> (-B) - A. */ 1092 if (negate_expr_p (TREE_OPERAND (t, 1)) 1093 && reorder_operands_p (TREE_OPERAND (t, 0), 1094 TREE_OPERAND (t, 1))) 1095 return true; 1096 /* -(A + B) -> (-A) - B. */ 1097 return negate_expr_p (TREE_OPERAND (t, 0)); 1098 1099 case MINUS_EXPR: 1100 /* We can't turn -(A-B) into B-A when we honor signed zeros. */ 1101 return (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations) 1102 && reorder_operands_p (TREE_OPERAND (t, 0), 1103 TREE_OPERAND (t, 1)); 1104 1105 case MULT_EXPR: 1106 if (TYPE_UNSIGNED (TREE_TYPE (t))) 1107 break; 1108 1109 /* Fall through. */ 1110 1111 case RDIV_EXPR: 1112 if (! HONOR_SIGN_DEPENDENT_ROUNDING (TYPE_MODE (TREE_TYPE (t)))) 1113 return negate_expr_p (TREE_OPERAND (t, 1)) 1114 || negate_expr_p (TREE_OPERAND (t, 0)); 1115 break; 1116 1117 case TRUNC_DIV_EXPR: 1118 case ROUND_DIV_EXPR: 1119 case FLOOR_DIV_EXPR: 1120 case CEIL_DIV_EXPR: 1121 case EXACT_DIV_EXPR: 1122 /* In general we can't negate A / B, because if A is INT_MIN and 1123 B is 1, we may turn this into INT_MIN / -1 which is undefined 1124 and actually traps on some architectures. But if overflow is 1125 undefined, we can negate, because - (INT_MIN / 1) is an 1126 overflow. */ 1127 if (INTEGRAL_TYPE_P (TREE_TYPE (t)) 1128 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (t))) 1129 break; 1130 return negate_expr_p (TREE_OPERAND (t, 1)) 1131 || negate_expr_p (TREE_OPERAND (t, 0)); 1132 1133 case NOP_EXPR: 1134 /* Negate -((double)float) as (double)(-float). */ 1135 if (TREE_CODE (type) == REAL_TYPE) 1136 { 1137 tree tem = strip_float_extensions (t); 1138 if (tem != t) 1139 return negate_expr_p (tem); 1140 } 1141 break; 1142 1143 case CALL_EXPR: 1144 /* Negate -f(x) as f(-x). */ 1145 if (negate_mathfn_p (builtin_mathfn_code (t))) 1146 return negate_expr_p (TREE_VALUE (TREE_OPERAND (t, 1))); 1147 break; 1148 1149 case RSHIFT_EXPR: 1150 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */ 1151 if (TREE_CODE (TREE_OPERAND (t, 1)) == INTEGER_CST) 1152 { 1153 tree op1 = TREE_OPERAND (t, 1); 1154 if (TREE_INT_CST_HIGH (op1) == 0 1155 && (unsigned HOST_WIDE_INT) (TYPE_PRECISION (type) - 1) 1156 == TREE_INT_CST_LOW (op1)) 1157 return true; 1158 } 1159 break; 1160 1161 default: 1162 break; 1163 } 1164 return false; 1165} 1166 1167/* Given T, an expression, return a folded tree for -T or NULL_TREE, if no 1168 simplification is possible. 1169 If negate_expr_p would return true for T, NULL_TREE will never be 1170 returned. */ 1171 1172static tree 1173fold_negate_expr (tree t) 1174{ 1175 tree type = TREE_TYPE (t); 1176 tree tem; 1177 1178 switch (TREE_CODE (t)) 1179 { 1180 /* Convert - (~A) to A + 1. */ 1181 case BIT_NOT_EXPR: 1182 if (INTEGRAL_TYPE_P (type)) 1183 return fold_build2 (PLUS_EXPR, type, TREE_OPERAND (t, 0), 1184 build_int_cst (type, 1)); 1185 break; 1186 1187 case INTEGER_CST: 1188 tem = fold_negate_const (t, type); 1189 if (!TREE_OVERFLOW (tem) 1190 || !TYPE_OVERFLOW_TRAPS (type)) 1191 return tem; 1192 break; 1193 1194 case REAL_CST: 1195 tem = fold_negate_const (t, type); 1196 /* Two's complement FP formats, such as c4x, may overflow. */ 1197 if (! TREE_OVERFLOW (tem) || ! flag_trapping_math) 1198 return tem; 1199 break; 1200 1201 case COMPLEX_CST: 1202 { 1203 tree rpart = negate_expr (TREE_REALPART (t)); 1204 tree ipart = negate_expr (TREE_IMAGPART (t)); 1205 1206 if ((TREE_CODE (rpart) == REAL_CST 1207 && TREE_CODE (ipart) == REAL_CST) 1208 || (TREE_CODE (rpart) == INTEGER_CST 1209 && TREE_CODE (ipart) == INTEGER_CST)) 1210 return build_complex (type, rpart, ipart); 1211 } 1212 break; 1213 1214 case NEGATE_EXPR: 1215 return TREE_OPERAND (t, 0); 1216 1217 case PLUS_EXPR: 1218 if (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations) 1219 { 1220 /* -(A + B) -> (-B) - A. */ 1221 if (negate_expr_p (TREE_OPERAND (t, 1)) 1222 && reorder_operands_p (TREE_OPERAND (t, 0), 1223 TREE_OPERAND (t, 1))) 1224 { 1225 tem = negate_expr (TREE_OPERAND (t, 1)); 1226 return fold_build2 (MINUS_EXPR, type, 1227 tem, TREE_OPERAND (t, 0)); 1228 } 1229 1230 /* -(A + B) -> (-A) - B. */ 1231 if (negate_expr_p (TREE_OPERAND (t, 0))) 1232 { 1233 tem = negate_expr (TREE_OPERAND (t, 0)); 1234 return fold_build2 (MINUS_EXPR, type, 1235 tem, TREE_OPERAND (t, 1)); 1236 } 1237 } 1238 break; 1239 1240 case MINUS_EXPR: 1241 /* - (A - B) -> B - A */ 1242 if ((! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations) 1243 && reorder_operands_p (TREE_OPERAND (t, 0), TREE_OPERAND (t, 1))) 1244 return fold_build2 (MINUS_EXPR, type, 1245 TREE_OPERAND (t, 1), TREE_OPERAND (t, 0)); 1246 break; 1247 1248 case MULT_EXPR: 1249 if (TYPE_UNSIGNED (type)) 1250 break; 1251 1252 /* Fall through. */ 1253 1254 case RDIV_EXPR: 1255 if (! HONOR_SIGN_DEPENDENT_ROUNDING (TYPE_MODE (type))) 1256 { 1257 tem = TREE_OPERAND (t, 1); 1258 if (negate_expr_p (tem)) 1259 return fold_build2 (TREE_CODE (t), type, 1260 TREE_OPERAND (t, 0), negate_expr (tem)); 1261 tem = TREE_OPERAND (t, 0); 1262 if (negate_expr_p (tem)) 1263 return fold_build2 (TREE_CODE (t), type, 1264 negate_expr (tem), TREE_OPERAND (t, 1)); 1265 } 1266 break; 1267 1268 case TRUNC_DIV_EXPR: 1269 case ROUND_DIV_EXPR: 1270 case FLOOR_DIV_EXPR: 1271 case CEIL_DIV_EXPR: 1272 case EXACT_DIV_EXPR: 1273 /* In general we can't negate A / B, because if A is INT_MIN and 1274 B is 1, we may turn this into INT_MIN / -1 which is undefined 1275 and actually traps on some architectures. But if overflow is 1276 undefined, we can negate, because - (INT_MIN / 1) is an 1277 overflow. */ 1278 if (!INTEGRAL_TYPE_P (type) || TYPE_OVERFLOW_UNDEFINED (type)) 1279 { 1280 const char * const warnmsg = G_("assuming signed overflow does not " 1281 "occur when negating a division"); 1282 tem = TREE_OPERAND (t, 1); 1283 if (negate_expr_p (tem)) 1284 { 1285 if (INTEGRAL_TYPE_P (type) 1286 && (TREE_CODE (tem) != INTEGER_CST 1287 || integer_onep (tem))) 1288 fold_overflow_warning (warnmsg, WARN_STRICT_OVERFLOW_MISC); 1289 return fold_build2 (TREE_CODE (t), type, 1290 TREE_OPERAND (t, 0), negate_expr (tem)); 1291 } 1292 tem = TREE_OPERAND (t, 0); 1293 if (negate_expr_p (tem)) 1294 { 1295 if (INTEGRAL_TYPE_P (type) 1296 && (TREE_CODE (tem) != INTEGER_CST 1297 || tree_int_cst_equal (tem, TYPE_MIN_VALUE (type)))) 1298 fold_overflow_warning (warnmsg, WARN_STRICT_OVERFLOW_MISC); 1299 return fold_build2 (TREE_CODE (t), type, 1300 negate_expr (tem), TREE_OPERAND (t, 1)); 1301 } 1302 } 1303 break; 1304 1305 case NOP_EXPR: 1306 /* Convert -((double)float) into (double)(-float). */ 1307 if (TREE_CODE (type) == REAL_TYPE) 1308 { 1309 tem = strip_float_extensions (t); 1310 if (tem != t && negate_expr_p (tem)) 1311 return negate_expr (tem); 1312 } 1313 break; 1314 1315 case CALL_EXPR: 1316 /* Negate -f(x) as f(-x). */ 1317 if (negate_mathfn_p (builtin_mathfn_code (t)) 1318 && negate_expr_p (TREE_VALUE (TREE_OPERAND (t, 1)))) 1319 { 1320 tree fndecl, arg, arglist; 1321 1322 fndecl = get_callee_fndecl (t); 1323 arg = negate_expr (TREE_VALUE (TREE_OPERAND (t, 1))); 1324 arglist = build_tree_list (NULL_TREE, arg); 1325 return build_function_call_expr (fndecl, arglist); 1326 } 1327 break; 1328 1329 case RSHIFT_EXPR: 1330 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */ 1331 if (TREE_CODE (TREE_OPERAND (t, 1)) == INTEGER_CST) 1332 { 1333 tree op1 = TREE_OPERAND (t, 1); 1334 if (TREE_INT_CST_HIGH (op1) == 0 1335 && (unsigned HOST_WIDE_INT) (TYPE_PRECISION (type) - 1) 1336 == TREE_INT_CST_LOW (op1)) 1337 { 1338 tree ntype = TYPE_UNSIGNED (type) 1339 ? lang_hooks.types.signed_type (type) 1340 : lang_hooks.types.unsigned_type (type); 1341 tree temp = fold_convert (ntype, TREE_OPERAND (t, 0)); 1342 temp = fold_build2 (RSHIFT_EXPR, ntype, temp, op1); 1343 return fold_convert (type, temp); 1344 } 1345 } 1346 break; 1347 1348 default: 1349 break; 1350 } 1351 1352 return NULL_TREE; 1353} 1354 1355/* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be 1356 negated in a simpler way. Also allow for T to be NULL_TREE, in which case 1357 return NULL_TREE. */ 1358 1359static tree 1360negate_expr (tree t) 1361{ 1362 tree type, tem; 1363 1364 if (t == NULL_TREE) 1365 return NULL_TREE; 1366 1367 type = TREE_TYPE (t); 1368 STRIP_SIGN_NOPS (t); 1369 1370 tem = fold_negate_expr (t); 1371 if (!tem) 1372 tem = build1 (NEGATE_EXPR, TREE_TYPE (t), t); 1373 return fold_convert (type, tem); 1374} 1375 1376/* Split a tree IN into a constant, literal and variable parts that could be 1377 combined with CODE to make IN. "constant" means an expression with 1378 TREE_CONSTANT but that isn't an actual constant. CODE must be a 1379 commutative arithmetic operation. Store the constant part into *CONP, 1380 the literal in *LITP and return the variable part. If a part isn't 1381 present, set it to null. If the tree does not decompose in this way, 1382 return the entire tree as the variable part and the other parts as null. 1383 1384 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that 1385 case, we negate an operand that was subtracted. Except if it is a 1386 literal for which we use *MINUS_LITP instead. 1387 1388 If NEGATE_P is true, we are negating all of IN, again except a literal 1389 for which we use *MINUS_LITP instead. 1390 1391 If IN is itself a literal or constant, return it as appropriate. 1392 1393 Note that we do not guarantee that any of the three values will be the 1394 same type as IN, but they will have the same signedness and mode. */ 1395 1396static tree 1397split_tree (tree in, enum tree_code code, tree *conp, tree *litp, 1398 tree *minus_litp, int negate_p) 1399{ 1400 tree var = 0; 1401 1402 *conp = 0; 1403 *litp = 0; 1404 *minus_litp = 0; 1405 1406 /* Strip any conversions that don't change the machine mode or signedness. */ 1407 STRIP_SIGN_NOPS (in); 1408 1409 if (TREE_CODE (in) == INTEGER_CST || TREE_CODE (in) == REAL_CST) 1410 *litp = in; 1411 else if (TREE_CODE (in) == code 1412 || (! FLOAT_TYPE_P (TREE_TYPE (in)) 1413 /* We can associate addition and subtraction together (even 1414 though the C standard doesn't say so) for integers because 1415 the value is not affected. For reals, the value might be 1416 affected, so we can't. */ 1417 && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR) 1418 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR)))) 1419 { 1420 tree op0 = TREE_OPERAND (in, 0); 1421 tree op1 = TREE_OPERAND (in, 1); 1422 int neg1_p = TREE_CODE (in) == MINUS_EXPR; 1423 int neg_litp_p = 0, neg_conp_p = 0, neg_var_p = 0; 1424 1425 /* First see if either of the operands is a literal, then a constant. */ 1426 if (TREE_CODE (op0) == INTEGER_CST || TREE_CODE (op0) == REAL_CST) 1427 *litp = op0, op0 = 0; 1428 else if (TREE_CODE (op1) == INTEGER_CST || TREE_CODE (op1) == REAL_CST) 1429 *litp = op1, neg_litp_p = neg1_p, op1 = 0; 1430 1431 if (op0 != 0 && TREE_CONSTANT (op0)) 1432 *conp = op0, op0 = 0; 1433 else if (op1 != 0 && TREE_CONSTANT (op1)) 1434 *conp = op1, neg_conp_p = neg1_p, op1 = 0; 1435 1436 /* If we haven't dealt with either operand, this is not a case we can 1437 decompose. Otherwise, VAR is either of the ones remaining, if any. */ 1438 if (op0 != 0 && op1 != 0) 1439 var = in; 1440 else if (op0 != 0) 1441 var = op0; 1442 else 1443 var = op1, neg_var_p = neg1_p; 1444 1445 /* Now do any needed negations. */ 1446 if (neg_litp_p) 1447 *minus_litp = *litp, *litp = 0; 1448 if (neg_conp_p) 1449 *conp = negate_expr (*conp); 1450 if (neg_var_p) 1451 var = negate_expr (var); 1452 } 1453 else if (TREE_CONSTANT (in)) 1454 *conp = in; 1455 else 1456 var = in; 1457 1458 if (negate_p) 1459 { 1460 if (*litp) 1461 *minus_litp = *litp, *litp = 0; 1462 else if (*minus_litp) 1463 *litp = *minus_litp, *minus_litp = 0; 1464 *conp = negate_expr (*conp); 1465 var = negate_expr (var); 1466 } 1467 1468 return var; 1469} 1470 1471/* Re-associate trees split by the above function. T1 and T2 are either 1472 expressions to associate or null. Return the new expression, if any. If 1473 we build an operation, do it in TYPE and with CODE. */ 1474 1475static tree 1476associate_trees (tree t1, tree t2, enum tree_code code, tree type) 1477{ 1478 if (t1 == 0) 1479 return t2; 1480 else if (t2 == 0) 1481 return t1; 1482 1483 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't 1484 try to fold this since we will have infinite recursion. But do 1485 deal with any NEGATE_EXPRs. */ 1486 if (TREE_CODE (t1) == code || TREE_CODE (t2) == code 1487 || TREE_CODE (t1) == MINUS_EXPR || TREE_CODE (t2) == MINUS_EXPR) 1488 { 1489 if (code == PLUS_EXPR) 1490 { 1491 if (TREE_CODE (t1) == NEGATE_EXPR) 1492 return build2 (MINUS_EXPR, type, fold_convert (type, t2), 1493 fold_convert (type, TREE_OPERAND (t1, 0))); 1494 else if (TREE_CODE (t2) == NEGATE_EXPR) 1495 return build2 (MINUS_EXPR, type, fold_convert (type, t1), 1496 fold_convert (type, TREE_OPERAND (t2, 0))); 1497 else if (integer_zerop (t2)) 1498 return fold_convert (type, t1); 1499 } 1500 else if (code == MINUS_EXPR) 1501 { 1502 if (integer_zerop (t2)) 1503 return fold_convert (type, t1); 1504 } 1505 1506 return build2 (code, type, fold_convert (type, t1), 1507 fold_convert (type, t2)); 1508 } 1509 1510 return fold_build2 (code, type, fold_convert (type, t1), 1511 fold_convert (type, t2)); 1512} 1513 1514/* Combine two integer constants ARG1 and ARG2 under operation CODE 1515 to produce a new constant. Return NULL_TREE if we don't know how 1516 to evaluate CODE at compile-time. 1517 1518 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */ 1519 1520tree 1521int_const_binop (enum tree_code code, tree arg1, tree arg2, int notrunc) 1522{ 1523 unsigned HOST_WIDE_INT int1l, int2l; 1524 HOST_WIDE_INT int1h, int2h; 1525 unsigned HOST_WIDE_INT low; 1526 HOST_WIDE_INT hi; 1527 unsigned HOST_WIDE_INT garbagel; 1528 HOST_WIDE_INT garbageh; 1529 tree t; 1530 tree type = TREE_TYPE (arg1); 1531 int uns = TYPE_UNSIGNED (type); 1532 int is_sizetype 1533 = (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type)); 1534 int overflow = 0; 1535 1536 int1l = TREE_INT_CST_LOW (arg1); 1537 int1h = TREE_INT_CST_HIGH (arg1); 1538 int2l = TREE_INT_CST_LOW (arg2); 1539 int2h = TREE_INT_CST_HIGH (arg2); 1540 1541 switch (code) 1542 { 1543 case BIT_IOR_EXPR: 1544 low = int1l | int2l, hi = int1h | int2h; 1545 break; 1546 1547 case BIT_XOR_EXPR: 1548 low = int1l ^ int2l, hi = int1h ^ int2h; 1549 break; 1550 1551 case BIT_AND_EXPR: 1552 low = int1l & int2l, hi = int1h & int2h; 1553 break; 1554 1555 case RSHIFT_EXPR: 1556 int2l = -int2l; 1557 case LSHIFT_EXPR: 1558 /* It's unclear from the C standard whether shifts can overflow. 1559 The following code ignores overflow; perhaps a C standard 1560 interpretation ruling is needed. */ 1561 lshift_double (int1l, int1h, int2l, TYPE_PRECISION (type), 1562 &low, &hi, !uns); 1563 break; 1564 1565 case RROTATE_EXPR: 1566 int2l = - int2l; 1567 case LROTATE_EXPR: 1568 lrotate_double (int1l, int1h, int2l, TYPE_PRECISION (type), 1569 &low, &hi); 1570 break; 1571 1572 case PLUS_EXPR: 1573 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi); 1574 break; 1575 1576 case MINUS_EXPR: 1577 neg_double (int2l, int2h, &low, &hi); 1578 add_double (int1l, int1h, low, hi, &low, &hi); 1579 overflow = OVERFLOW_SUM_SIGN (hi, int2h, int1h); 1580 break; 1581 1582 case MULT_EXPR: 1583 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi); 1584 break; 1585 1586 case TRUNC_DIV_EXPR: 1587 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR: 1588 case EXACT_DIV_EXPR: 1589 /* This is a shortcut for a common special case. */ 1590 if (int2h == 0 && (HOST_WIDE_INT) int2l > 0 1591 && ! TREE_CONSTANT_OVERFLOW (arg1) 1592 && ! TREE_CONSTANT_OVERFLOW (arg2) 1593 && int1h == 0 && (HOST_WIDE_INT) int1l >= 0) 1594 { 1595 if (code == CEIL_DIV_EXPR) 1596 int1l += int2l - 1; 1597 1598 low = int1l / int2l, hi = 0; 1599 break; 1600 } 1601 1602 /* ... fall through ... */ 1603 1604 case ROUND_DIV_EXPR: 1605 if (int2h == 0 && int2l == 0) 1606 return NULL_TREE; 1607 if (int2h == 0 && int2l == 1) 1608 { 1609 low = int1l, hi = int1h; 1610 break; 1611 } 1612 if (int1l == int2l && int1h == int2h 1613 && ! (int1l == 0 && int1h == 0)) 1614 { 1615 low = 1, hi = 0; 1616 break; 1617 } 1618 overflow = div_and_round_double (code, uns, int1l, int1h, int2l, int2h, 1619 &low, &hi, &garbagel, &garbageh); 1620 break; 1621 1622 case TRUNC_MOD_EXPR: 1623 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR: 1624 /* This is a shortcut for a common special case. */ 1625 if (int2h == 0 && (HOST_WIDE_INT) int2l > 0 1626 && ! TREE_CONSTANT_OVERFLOW (arg1) 1627 && ! TREE_CONSTANT_OVERFLOW (arg2) 1628 && int1h == 0 && (HOST_WIDE_INT) int1l >= 0) 1629 { 1630 if (code == CEIL_MOD_EXPR) 1631 int1l += int2l - 1; 1632 low = int1l % int2l, hi = 0; 1633 break; 1634 } 1635 1636 /* ... fall through ... */ 1637 1638 case ROUND_MOD_EXPR: 1639 if (int2h == 0 && int2l == 0) 1640 return NULL_TREE; 1641 overflow = div_and_round_double (code, uns, 1642 int1l, int1h, int2l, int2h, 1643 &garbagel, &garbageh, &low, &hi); 1644 break; 1645 1646 case MIN_EXPR: 1647 case MAX_EXPR: 1648 if (uns) 1649 low = (((unsigned HOST_WIDE_INT) int1h 1650 < (unsigned HOST_WIDE_INT) int2h) 1651 || (((unsigned HOST_WIDE_INT) int1h 1652 == (unsigned HOST_WIDE_INT) int2h) 1653 && int1l < int2l)); 1654 else 1655 low = (int1h < int2h 1656 || (int1h == int2h && int1l < int2l)); 1657 1658 if (low == (code == MIN_EXPR)) 1659 low = int1l, hi = int1h; 1660 else 1661 low = int2l, hi = int2h; 1662 break; 1663 1664 default: 1665 return NULL_TREE; 1666 } 1667 1668 t = build_int_cst_wide (TREE_TYPE (arg1), low, hi); 1669 1670 if (notrunc) 1671 { 1672 /* Propagate overflow flags ourselves. */ 1673 if (((!uns || is_sizetype) && overflow) 1674 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2)) 1675 { 1676 t = copy_node (t); 1677 TREE_OVERFLOW (t) = 1; 1678 TREE_CONSTANT_OVERFLOW (t) = 1; 1679 } 1680 else if (TREE_CONSTANT_OVERFLOW (arg1) | TREE_CONSTANT_OVERFLOW (arg2)) 1681 { 1682 t = copy_node (t); 1683 TREE_CONSTANT_OVERFLOW (t) = 1; 1684 } 1685 } 1686 else 1687 t = force_fit_type (t, 1, 1688 ((!uns || is_sizetype) && overflow) 1689 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2), 1690 TREE_CONSTANT_OVERFLOW (arg1) 1691 | TREE_CONSTANT_OVERFLOW (arg2)); 1692 1693 return t; 1694} 1695 1696/* Combine two constants ARG1 and ARG2 under operation CODE to produce a new 1697 constant. We assume ARG1 and ARG2 have the same data type, or at least 1698 are the same kind of constant and the same machine mode. Return zero if 1699 combining the constants is not allowed in the current operating mode. 1700 1701 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */ 1702 1703static tree 1704const_binop (enum tree_code code, tree arg1, tree arg2, int notrunc) 1705{ 1706 /* Sanity check for the recursive cases. */ 1707 if (!arg1 || !arg2) 1708 return NULL_TREE; 1709 1710 STRIP_NOPS (arg1); 1711 STRIP_NOPS (arg2); 1712 1713 if (TREE_CODE (arg1) == INTEGER_CST) 1714 return int_const_binop (code, arg1, arg2, notrunc); 1715 1716 if (TREE_CODE (arg1) == REAL_CST) 1717 { 1718 enum machine_mode mode; 1719 REAL_VALUE_TYPE d1; 1720 REAL_VALUE_TYPE d2; 1721 REAL_VALUE_TYPE value; 1722 REAL_VALUE_TYPE result; 1723 bool inexact; 1724 tree t, type; 1725 1726 /* The following codes are handled by real_arithmetic. */ 1727 switch (code) 1728 { 1729 case PLUS_EXPR: 1730 case MINUS_EXPR: 1731 case MULT_EXPR: 1732 case RDIV_EXPR: 1733 case MIN_EXPR: 1734 case MAX_EXPR: 1735 break; 1736 1737 default: 1738 return NULL_TREE; 1739 } 1740 1741 d1 = TREE_REAL_CST (arg1); 1742 d2 = TREE_REAL_CST (arg2); 1743 1744 type = TREE_TYPE (arg1); 1745 mode = TYPE_MODE (type); 1746 1747 /* Don't perform operation if we honor signaling NaNs and 1748 either operand is a NaN. */ 1749 if (HONOR_SNANS (mode) 1750 && (REAL_VALUE_ISNAN (d1) || REAL_VALUE_ISNAN (d2))) 1751 return NULL_TREE; 1752 1753 /* Don't perform operation if it would raise a division 1754 by zero exception. */ 1755 if (code == RDIV_EXPR 1756 && REAL_VALUES_EQUAL (d2, dconst0) 1757 && (flag_trapping_math || ! MODE_HAS_INFINITIES (mode))) 1758 return NULL_TREE; 1759 1760 /* If either operand is a NaN, just return it. Otherwise, set up 1761 for floating-point trap; we return an overflow. */ 1762 if (REAL_VALUE_ISNAN (d1)) 1763 return arg1; 1764 else if (REAL_VALUE_ISNAN (d2)) 1765 return arg2; 1766 1767 inexact = real_arithmetic (&value, code, &d1, &d2); 1768 real_convert (&result, mode, &value); 1769 1770 /* Don't constant fold this floating point operation if 1771 the result has overflowed and flag_trapping_math. */ 1772 if (flag_trapping_math 1773 && MODE_HAS_INFINITIES (mode) 1774 && REAL_VALUE_ISINF (result) 1775 && !REAL_VALUE_ISINF (d1) 1776 && !REAL_VALUE_ISINF (d2)) 1777 return NULL_TREE; 1778 1779 /* Don't constant fold this floating point operation if the 1780 result may dependent upon the run-time rounding mode and 1781 flag_rounding_math is set, or if GCC's software emulation 1782 is unable to accurately represent the result. */ 1783 if ((flag_rounding_math 1784 || (REAL_MODE_FORMAT_COMPOSITE_P (mode) 1785 && !flag_unsafe_math_optimizations)) 1786 && (inexact || !real_identical (&result, &value))) 1787 return NULL_TREE; 1788 1789 t = build_real (type, result); 1790 1791 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2); 1792 TREE_CONSTANT_OVERFLOW (t) 1793 = TREE_OVERFLOW (t) 1794 | TREE_CONSTANT_OVERFLOW (arg1) 1795 | TREE_CONSTANT_OVERFLOW (arg2); 1796 return t; 1797 } 1798 1799 if (TREE_CODE (arg1) == COMPLEX_CST) 1800 { 1801 tree type = TREE_TYPE (arg1); 1802 tree r1 = TREE_REALPART (arg1); 1803 tree i1 = TREE_IMAGPART (arg1); 1804 tree r2 = TREE_REALPART (arg2); 1805 tree i2 = TREE_IMAGPART (arg2); 1806 tree real, imag; 1807 1808 switch (code) 1809 { 1810 case PLUS_EXPR: 1811 case MINUS_EXPR: 1812 real = const_binop (code, r1, r2, notrunc); 1813 imag = const_binop (code, i1, i2, notrunc); 1814 break; 1815 1816 case MULT_EXPR: 1817 real = const_binop (MINUS_EXPR, 1818 const_binop (MULT_EXPR, r1, r2, notrunc), 1819 const_binop (MULT_EXPR, i1, i2, notrunc), 1820 notrunc); 1821 imag = const_binop (PLUS_EXPR, 1822 const_binop (MULT_EXPR, r1, i2, notrunc), 1823 const_binop (MULT_EXPR, i1, r2, notrunc), 1824 notrunc); 1825 break; 1826 1827 case RDIV_EXPR: 1828 { 1829 tree magsquared 1830 = const_binop (PLUS_EXPR, 1831 const_binop (MULT_EXPR, r2, r2, notrunc), 1832 const_binop (MULT_EXPR, i2, i2, notrunc), 1833 notrunc); 1834 tree t1 1835 = const_binop (PLUS_EXPR, 1836 const_binop (MULT_EXPR, r1, r2, notrunc), 1837 const_binop (MULT_EXPR, i1, i2, notrunc), 1838 notrunc); 1839 tree t2 1840 = const_binop (MINUS_EXPR, 1841 const_binop (MULT_EXPR, i1, r2, notrunc), 1842 const_binop (MULT_EXPR, r1, i2, notrunc), 1843 notrunc); 1844 1845 if (INTEGRAL_TYPE_P (TREE_TYPE (r1))) 1846 code = TRUNC_DIV_EXPR; 1847 1848 real = const_binop (code, t1, magsquared, notrunc); 1849 imag = const_binop (code, t2, magsquared, notrunc); 1850 } 1851 break; 1852 1853 default: 1854 return NULL_TREE; 1855 } 1856 1857 if (real && imag) 1858 return build_complex (type, real, imag); 1859 } 1860 1861 return NULL_TREE; 1862} 1863 1864/* Create a size type INT_CST node with NUMBER sign extended. KIND 1865 indicates which particular sizetype to create. */ 1866 1867tree 1868size_int_kind (HOST_WIDE_INT number, enum size_type_kind kind) 1869{ 1870 return build_int_cst (sizetype_tab[(int) kind], number); 1871} 1872 1873/* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE 1874 is a tree code. The type of the result is taken from the operands. 1875 Both must be the same type integer type and it must be a size type. 1876 If the operands are constant, so is the result. */ 1877 1878tree 1879size_binop (enum tree_code code, tree arg0, tree arg1) 1880{ 1881 tree type = TREE_TYPE (arg0); 1882 1883 if (arg0 == error_mark_node || arg1 == error_mark_node) 1884 return error_mark_node; 1885 1886 gcc_assert (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type) 1887 && type == TREE_TYPE (arg1)); 1888 1889 /* Handle the special case of two integer constants faster. */ 1890 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) 1891 { 1892 /* And some specific cases even faster than that. */ 1893 if (code == PLUS_EXPR && integer_zerop (arg0)) 1894 return arg1; 1895 else if ((code == MINUS_EXPR || code == PLUS_EXPR) 1896 && integer_zerop (arg1)) 1897 return arg0; 1898 else if (code == MULT_EXPR && integer_onep (arg0)) 1899 return arg1; 1900 1901 /* Handle general case of two integer constants. */ 1902 return int_const_binop (code, arg0, arg1, 0); 1903 } 1904 1905 return fold_build2 (code, type, arg0, arg1); 1906} 1907 1908/* Given two values, either both of sizetype or both of bitsizetype, 1909 compute the difference between the two values. Return the value 1910 in signed type corresponding to the type of the operands. */ 1911 1912tree 1913size_diffop (tree arg0, tree arg1) 1914{ 1915 tree type = TREE_TYPE (arg0); 1916 tree ctype; 1917 1918 gcc_assert (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type) 1919 && type == TREE_TYPE (arg1)); 1920 1921 /* If the type is already signed, just do the simple thing. */ 1922 if (!TYPE_UNSIGNED (type)) 1923 return size_binop (MINUS_EXPR, arg0, arg1); 1924 1925 ctype = type == bitsizetype ? sbitsizetype : ssizetype; 1926 1927 /* If either operand is not a constant, do the conversions to the signed 1928 type and subtract. The hardware will do the right thing with any 1929 overflow in the subtraction. */ 1930 if (TREE_CODE (arg0) != INTEGER_CST || TREE_CODE (arg1) != INTEGER_CST) 1931 return size_binop (MINUS_EXPR, fold_convert (ctype, arg0), 1932 fold_convert (ctype, arg1)); 1933 1934 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE. 1935 Otherwise, subtract the other way, convert to CTYPE (we know that can't 1936 overflow) and negate (which can't either). Special-case a result 1937 of zero while we're here. */ 1938 if (tree_int_cst_equal (arg0, arg1)) 1939 return build_int_cst (ctype, 0); 1940 else if (tree_int_cst_lt (arg1, arg0)) 1941 return fold_convert (ctype, size_binop (MINUS_EXPR, arg0, arg1)); 1942 else 1943 return size_binop (MINUS_EXPR, build_int_cst (ctype, 0), 1944 fold_convert (ctype, size_binop (MINUS_EXPR, 1945 arg1, arg0))); 1946} 1947 1948/* A subroutine of fold_convert_const handling conversions of an 1949 INTEGER_CST to another integer type. */ 1950 1951static tree 1952fold_convert_const_int_from_int (tree type, tree arg1) 1953{ 1954 tree t; 1955 1956 /* Given an integer constant, make new constant with new type, 1957 appropriately sign-extended or truncated. */ 1958 t = build_int_cst_wide (type, TREE_INT_CST_LOW (arg1), 1959 TREE_INT_CST_HIGH (arg1)); 1960 1961 t = force_fit_type (t, 1962 /* Don't set the overflow when 1963 converting a pointer */ 1964 !POINTER_TYPE_P (TREE_TYPE (arg1)), 1965 (TREE_INT_CST_HIGH (arg1) < 0 1966 && (TYPE_UNSIGNED (type) 1967 < TYPE_UNSIGNED (TREE_TYPE (arg1)))) 1968 | TREE_OVERFLOW (arg1), 1969 TREE_CONSTANT_OVERFLOW (arg1)); 1970 1971 return t; 1972} 1973 1974/* A subroutine of fold_convert_const handling conversions a REAL_CST 1975 to an integer type. */ 1976 1977static tree 1978fold_convert_const_int_from_real (enum tree_code code, tree type, tree arg1) 1979{ 1980 int overflow = 0; 1981 tree t; 1982 1983 /* The following code implements the floating point to integer 1984 conversion rules required by the Java Language Specification, 1985 that IEEE NaNs are mapped to zero and values that overflow 1986 the target precision saturate, i.e. values greater than 1987 INT_MAX are mapped to INT_MAX, and values less than INT_MIN 1988 are mapped to INT_MIN. These semantics are allowed by the 1989 C and C++ standards that simply state that the behavior of 1990 FP-to-integer conversion is unspecified upon overflow. */ 1991 1992 HOST_WIDE_INT high, low; 1993 REAL_VALUE_TYPE r; 1994 REAL_VALUE_TYPE x = TREE_REAL_CST (arg1); 1995 1996 switch (code) 1997 { 1998 case FIX_TRUNC_EXPR: 1999 real_trunc (&r, VOIDmode, &x); 2000 break; 2001 2002 case FIX_CEIL_EXPR: 2003 real_ceil (&r, VOIDmode, &x); 2004 break; 2005 2006 case FIX_FLOOR_EXPR: 2007 real_floor (&r, VOIDmode, &x); 2008 break; 2009 2010 case FIX_ROUND_EXPR: 2011 real_round (&r, VOIDmode, &x); 2012 break; 2013 2014 default: 2015 gcc_unreachable (); 2016 } 2017 2018 /* If R is NaN, return zero and show we have an overflow. */ 2019 if (REAL_VALUE_ISNAN (r)) 2020 { 2021 overflow = 1; 2022 high = 0; 2023 low = 0; 2024 } 2025 2026 /* See if R is less than the lower bound or greater than the 2027 upper bound. */ 2028 2029 if (! overflow) 2030 { 2031 tree lt = TYPE_MIN_VALUE (type); 2032 REAL_VALUE_TYPE l = real_value_from_int_cst (NULL_TREE, lt); 2033 if (REAL_VALUES_LESS (r, l)) 2034 { 2035 overflow = 1; 2036 high = TREE_INT_CST_HIGH (lt); 2037 low = TREE_INT_CST_LOW (lt); 2038 } 2039 } 2040 2041 if (! overflow) 2042 { 2043 tree ut = TYPE_MAX_VALUE (type); 2044 if (ut) 2045 { 2046 REAL_VALUE_TYPE u = real_value_from_int_cst (NULL_TREE, ut); 2047 if (REAL_VALUES_LESS (u, r)) 2048 { 2049 overflow = 1; 2050 high = TREE_INT_CST_HIGH (ut); 2051 low = TREE_INT_CST_LOW (ut); 2052 } 2053 } 2054 } 2055 2056 if (! overflow) 2057 REAL_VALUE_TO_INT (&low, &high, r); 2058 2059 t = build_int_cst_wide (type, low, high); 2060 2061 t = force_fit_type (t, -1, overflow | TREE_OVERFLOW (arg1), 2062 TREE_CONSTANT_OVERFLOW (arg1)); 2063 return t; 2064} 2065 2066/* A subroutine of fold_convert_const handling conversions a REAL_CST 2067 to another floating point type. */ 2068 2069static tree 2070fold_convert_const_real_from_real (tree type, tree arg1) 2071{ 2072 REAL_VALUE_TYPE value; 2073 tree t; 2074 2075 real_convert (&value, TYPE_MODE (type), &TREE_REAL_CST (arg1)); 2076 t = build_real (type, value); 2077 2078 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg1); 2079 TREE_CONSTANT_OVERFLOW (t) 2080 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1); 2081 return t; 2082} 2083 2084/* Attempt to fold type conversion operation CODE of expression ARG1 to 2085 type TYPE. If no simplification can be done return NULL_TREE. */ 2086 2087static tree 2088fold_convert_const (enum tree_code code, tree type, tree arg1) 2089{ 2090 if (TREE_TYPE (arg1) == type) 2091 return arg1; 2092 2093 if (POINTER_TYPE_P (type) || INTEGRAL_TYPE_P (type)) 2094 { 2095 if (TREE_CODE (arg1) == INTEGER_CST) 2096 return fold_convert_const_int_from_int (type, arg1); 2097 else if (TREE_CODE (arg1) == REAL_CST) 2098 return fold_convert_const_int_from_real (code, type, arg1); 2099 } 2100 else if (TREE_CODE (type) == REAL_TYPE) 2101 { 2102 if (TREE_CODE (arg1) == INTEGER_CST) 2103 return build_real_from_int_cst (type, arg1); 2104 if (TREE_CODE (arg1) == REAL_CST) 2105 return fold_convert_const_real_from_real (type, arg1); 2106 } 2107 return NULL_TREE; 2108} 2109 2110/* Construct a vector of zero elements of vector type TYPE. */ 2111 2112static tree 2113build_zero_vector (tree type) 2114{ 2115 tree elem, list; 2116 int i, units; 2117 2118 elem = fold_convert_const (NOP_EXPR, TREE_TYPE (type), integer_zero_node); 2119 units = TYPE_VECTOR_SUBPARTS (type); 2120 2121 list = NULL_TREE; 2122 for (i = 0; i < units; i++) 2123 list = tree_cons (NULL_TREE, elem, list); 2124 return build_vector (type, list); 2125} 2126 2127/* Convert expression ARG to type TYPE. Used by the middle-end for 2128 simple conversions in preference to calling the front-end's convert. */ 2129 2130tree 2131fold_convert (tree type, tree arg) 2132{ 2133 tree orig = TREE_TYPE (arg); 2134 tree tem; 2135 2136 if (type == orig) 2137 return arg; 2138 2139 if (TREE_CODE (arg) == ERROR_MARK 2140 || TREE_CODE (type) == ERROR_MARK 2141 || TREE_CODE (orig) == ERROR_MARK) 2142 return error_mark_node; 2143 2144 if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (orig) 2145 || lang_hooks.types_compatible_p (TYPE_MAIN_VARIANT (type), 2146 TYPE_MAIN_VARIANT (orig))) 2147 return fold_build1 (NOP_EXPR, type, arg); 2148 2149 switch (TREE_CODE (type)) 2150 { 2151 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE: 2152 case POINTER_TYPE: case REFERENCE_TYPE: 2153 case OFFSET_TYPE: 2154 if (TREE_CODE (arg) == INTEGER_CST) 2155 { 2156 tem = fold_convert_const (NOP_EXPR, type, arg); 2157 if (tem != NULL_TREE) 2158 return tem; 2159 } 2160 if (INTEGRAL_TYPE_P (orig) || POINTER_TYPE_P (orig) 2161 || TREE_CODE (orig) == OFFSET_TYPE) 2162 return fold_build1 (NOP_EXPR, type, arg); 2163 if (TREE_CODE (orig) == COMPLEX_TYPE) 2164 { 2165 tem = fold_build1 (REALPART_EXPR, TREE_TYPE (orig), arg); 2166 return fold_convert (type, tem); 2167 } 2168 gcc_assert (TREE_CODE (orig) == VECTOR_TYPE 2169 && tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (orig))); 2170 return fold_build1 (NOP_EXPR, type, arg); 2171 2172 case REAL_TYPE: 2173 if (TREE_CODE (arg) == INTEGER_CST) 2174 { 2175 tem = fold_convert_const (FLOAT_EXPR, type, arg); 2176 if (tem != NULL_TREE) 2177 return tem; 2178 } 2179 else if (TREE_CODE (arg) == REAL_CST) 2180 { 2181 tem = fold_convert_const (NOP_EXPR, type, arg); 2182 if (tem != NULL_TREE) 2183 return tem; 2184 } 2185 2186 switch (TREE_CODE (orig)) 2187 { 2188 case INTEGER_TYPE: 2189 case BOOLEAN_TYPE: case ENUMERAL_TYPE: 2190 case POINTER_TYPE: case REFERENCE_TYPE: 2191 return fold_build1 (FLOAT_EXPR, type, arg); 2192 2193 case REAL_TYPE: 2194 return fold_build1 (NOP_EXPR, type, arg); 2195 2196 case COMPLEX_TYPE: 2197 tem = fold_build1 (REALPART_EXPR, TREE_TYPE (orig), arg); 2198 return fold_convert (type, tem); 2199 2200 default: 2201 gcc_unreachable (); 2202 } 2203 2204 case COMPLEX_TYPE: 2205 switch (TREE_CODE (orig)) 2206 { 2207 case INTEGER_TYPE: 2208 case BOOLEAN_TYPE: case ENUMERAL_TYPE: 2209 case POINTER_TYPE: case REFERENCE_TYPE: 2210 case REAL_TYPE: 2211 return build2 (COMPLEX_EXPR, type, 2212 fold_convert (TREE_TYPE (type), arg), 2213 fold_convert (TREE_TYPE (type), integer_zero_node)); 2214 case COMPLEX_TYPE: 2215 { 2216 tree rpart, ipart; 2217 2218 if (TREE_CODE (arg) == COMPLEX_EXPR) 2219 { 2220 rpart = fold_convert (TREE_TYPE (type), TREE_OPERAND (arg, 0)); 2221 ipart = fold_convert (TREE_TYPE (type), TREE_OPERAND (arg, 1)); 2222 return fold_build2 (COMPLEX_EXPR, type, rpart, ipart); 2223 } 2224 2225 arg = save_expr (arg); 2226 rpart = fold_build1 (REALPART_EXPR, TREE_TYPE (orig), arg); 2227 ipart = fold_build1 (IMAGPART_EXPR, TREE_TYPE (orig), arg); 2228 rpart = fold_convert (TREE_TYPE (type), rpart); 2229 ipart = fold_convert (TREE_TYPE (type), ipart); 2230 return fold_build2 (COMPLEX_EXPR, type, rpart, ipart); 2231 } 2232 2233 default: 2234 gcc_unreachable (); 2235 } 2236 2237 case VECTOR_TYPE: 2238 if (integer_zerop (arg)) 2239 return build_zero_vector (type); 2240 gcc_assert (tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (orig))); 2241 gcc_assert (INTEGRAL_TYPE_P (orig) || POINTER_TYPE_P (orig) 2242 || TREE_CODE (orig) == VECTOR_TYPE); 2243 return fold_build1 (VIEW_CONVERT_EXPR, type, arg); 2244 2245 case VOID_TYPE: 2246 return fold_build1 (NOP_EXPR, type, fold_ignored_result (arg)); 2247 2248 default: 2249 gcc_unreachable (); 2250 } 2251} 2252 2253/* Return false if expr can be assumed not to be an lvalue, true 2254 otherwise. */ 2255 2256static bool 2257maybe_lvalue_p (tree x) 2258{ 2259 /* We only need to wrap lvalue tree codes. */ 2260 switch (TREE_CODE (x)) 2261 { 2262 case VAR_DECL: 2263 case PARM_DECL: 2264 case RESULT_DECL: 2265 case LABEL_DECL: 2266 case FUNCTION_DECL: 2267 case SSA_NAME: 2268 2269 case COMPONENT_REF: 2270 case INDIRECT_REF: 2271 case ALIGN_INDIRECT_REF: 2272 case MISALIGNED_INDIRECT_REF: 2273 case ARRAY_REF: 2274 case ARRAY_RANGE_REF: 2275 case BIT_FIELD_REF: 2276 case OBJ_TYPE_REF: 2277 2278 case REALPART_EXPR: 2279 case IMAGPART_EXPR: 2280 case PREINCREMENT_EXPR: 2281 case PREDECREMENT_EXPR: 2282 case SAVE_EXPR: 2283 case TRY_CATCH_EXPR: 2284 case WITH_CLEANUP_EXPR: 2285 case COMPOUND_EXPR: 2286 case MODIFY_EXPR: 2287 case TARGET_EXPR: 2288 case COND_EXPR: 2289 case BIND_EXPR: 2290 case MIN_EXPR: 2291 case MAX_EXPR: 2292 break; 2293 2294 default: 2295 /* Assume the worst for front-end tree codes. */ 2296 if ((int)TREE_CODE (x) >= NUM_TREE_CODES) 2297 break; 2298 return false; 2299 } 2300 2301 return true; 2302} 2303 2304/* Return an expr equal to X but certainly not valid as an lvalue. */ 2305 2306tree 2307non_lvalue (tree x) 2308{ 2309 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to 2310 us. */ 2311 if (in_gimple_form) 2312 return x; 2313 2314 if (! maybe_lvalue_p (x)) 2315 return x; 2316 return build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x); 2317} 2318 2319/* Nonzero means lvalues are limited to those valid in pedantic ANSI C. 2320 Zero means allow extended lvalues. */ 2321 2322int pedantic_lvalues; 2323 2324/* When pedantic, return an expr equal to X but certainly not valid as a 2325 pedantic lvalue. Otherwise, return X. */ 2326 2327static tree 2328pedantic_non_lvalue (tree x) 2329{ 2330 if (pedantic_lvalues) 2331 return non_lvalue (x); 2332 else 2333 return x; 2334} 2335 2336/* Given a tree comparison code, return the code that is the logical inverse 2337 of the given code. It is not safe to do this for floating-point 2338 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode 2339 as well: if reversing the comparison is unsafe, return ERROR_MARK. */ 2340 2341enum tree_code 2342invert_tree_comparison (enum tree_code code, bool honor_nans) 2343{ 2344 if (honor_nans && flag_trapping_math) 2345 return ERROR_MARK; 2346 2347 switch (code) 2348 { 2349 case EQ_EXPR: 2350 return NE_EXPR; 2351 case NE_EXPR: 2352 return EQ_EXPR; 2353 case GT_EXPR: 2354 return honor_nans ? UNLE_EXPR : LE_EXPR; 2355 case GE_EXPR: 2356 return honor_nans ? UNLT_EXPR : LT_EXPR; 2357 case LT_EXPR: 2358 return honor_nans ? UNGE_EXPR : GE_EXPR; 2359 case LE_EXPR: 2360 return honor_nans ? UNGT_EXPR : GT_EXPR; 2361 case LTGT_EXPR: 2362 return UNEQ_EXPR; 2363 case UNEQ_EXPR: 2364 return LTGT_EXPR; 2365 case UNGT_EXPR: 2366 return LE_EXPR; 2367 case UNGE_EXPR: 2368 return LT_EXPR; 2369 case UNLT_EXPR: 2370 return GE_EXPR; 2371 case UNLE_EXPR: 2372 return GT_EXPR; 2373 case ORDERED_EXPR: 2374 return UNORDERED_EXPR; 2375 case UNORDERED_EXPR: 2376 return ORDERED_EXPR; 2377 default: 2378 gcc_unreachable (); 2379 } 2380} 2381 2382/* Similar, but return the comparison that results if the operands are 2383 swapped. This is safe for floating-point. */ 2384 2385enum tree_code 2386swap_tree_comparison (enum tree_code code) 2387{ 2388 switch (code) 2389 { 2390 case EQ_EXPR: 2391 case NE_EXPR: 2392 case ORDERED_EXPR: 2393 case UNORDERED_EXPR: 2394 case LTGT_EXPR: 2395 case UNEQ_EXPR: 2396 return code; 2397 case GT_EXPR: 2398 return LT_EXPR; 2399 case GE_EXPR: 2400 return LE_EXPR; 2401 case LT_EXPR: 2402 return GT_EXPR; 2403 case LE_EXPR: 2404 return GE_EXPR; 2405 case UNGT_EXPR: 2406 return UNLT_EXPR; 2407 case UNGE_EXPR: 2408 return UNLE_EXPR; 2409 case UNLT_EXPR: 2410 return UNGT_EXPR; 2411 case UNLE_EXPR: 2412 return UNGE_EXPR; 2413 default: 2414 gcc_unreachable (); 2415 } 2416} 2417 2418 2419/* Convert a comparison tree code from an enum tree_code representation 2420 into a compcode bit-based encoding. This function is the inverse of 2421 compcode_to_comparison. */ 2422 2423static enum comparison_code 2424comparison_to_compcode (enum tree_code code) 2425{ 2426 switch (code) 2427 { 2428 case LT_EXPR: 2429 return COMPCODE_LT; 2430 case EQ_EXPR: 2431 return COMPCODE_EQ; 2432 case LE_EXPR: 2433 return COMPCODE_LE; 2434 case GT_EXPR: 2435 return COMPCODE_GT; 2436 case NE_EXPR: 2437 return COMPCODE_NE; 2438 case GE_EXPR: 2439 return COMPCODE_GE; 2440 case ORDERED_EXPR: 2441 return COMPCODE_ORD; 2442 case UNORDERED_EXPR: 2443 return COMPCODE_UNORD; 2444 case UNLT_EXPR: 2445 return COMPCODE_UNLT; 2446 case UNEQ_EXPR: 2447 return COMPCODE_UNEQ; 2448 case UNLE_EXPR: 2449 return COMPCODE_UNLE; 2450 case UNGT_EXPR: 2451 return COMPCODE_UNGT; 2452 case LTGT_EXPR: 2453 return COMPCODE_LTGT; 2454 case UNGE_EXPR: 2455 return COMPCODE_UNGE; 2456 default: 2457 gcc_unreachable (); 2458 } 2459} 2460 2461/* Convert a compcode bit-based encoding of a comparison operator back 2462 to GCC's enum tree_code representation. This function is the 2463 inverse of comparison_to_compcode. */ 2464 2465static enum tree_code 2466compcode_to_comparison (enum comparison_code code) 2467{ 2468 switch (code) 2469 { 2470 case COMPCODE_LT: 2471 return LT_EXPR; 2472 case COMPCODE_EQ: 2473 return EQ_EXPR; 2474 case COMPCODE_LE: 2475 return LE_EXPR; 2476 case COMPCODE_GT: 2477 return GT_EXPR; 2478 case COMPCODE_NE: 2479 return NE_EXPR; 2480 case COMPCODE_GE: 2481 return GE_EXPR; 2482 case COMPCODE_ORD: 2483 return ORDERED_EXPR; 2484 case COMPCODE_UNORD: 2485 return UNORDERED_EXPR; 2486 case COMPCODE_UNLT: 2487 return UNLT_EXPR; 2488 case COMPCODE_UNEQ: 2489 return UNEQ_EXPR; 2490 case COMPCODE_UNLE: 2491 return UNLE_EXPR; 2492 case COMPCODE_UNGT: 2493 return UNGT_EXPR; 2494 case COMPCODE_LTGT: 2495 return LTGT_EXPR; 2496 case COMPCODE_UNGE: 2497 return UNGE_EXPR; 2498 default: 2499 gcc_unreachable (); 2500 } 2501} 2502 2503/* Return a tree for the comparison which is the combination of 2504 doing the AND or OR (depending on CODE) of the two operations LCODE 2505 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account 2506 the possibility of trapping if the mode has NaNs, and return NULL_TREE 2507 if this makes the transformation invalid. */ 2508 2509tree 2510combine_comparisons (enum tree_code code, enum tree_code lcode, 2511 enum tree_code rcode, tree truth_type, 2512 tree ll_arg, tree lr_arg) 2513{ 2514 bool honor_nans = HONOR_NANS (TYPE_MODE (TREE_TYPE (ll_arg))); 2515 enum comparison_code lcompcode = comparison_to_compcode (lcode); 2516 enum comparison_code rcompcode = comparison_to_compcode (rcode); 2517 enum comparison_code compcode; 2518 2519 switch (code) 2520 { 2521 case TRUTH_AND_EXPR: case TRUTH_ANDIF_EXPR: 2522 compcode = lcompcode & rcompcode; 2523 break; 2524 2525 case TRUTH_OR_EXPR: case TRUTH_ORIF_EXPR: 2526 compcode = lcompcode | rcompcode; 2527 break; 2528 2529 default: 2530 return NULL_TREE; 2531 } 2532 2533 if (!honor_nans) 2534 { 2535 /* Eliminate unordered comparisons, as well as LTGT and ORD 2536 which are not used unless the mode has NaNs. */ 2537 compcode &= ~COMPCODE_UNORD; 2538 if (compcode == COMPCODE_LTGT) 2539 compcode = COMPCODE_NE; 2540 else if (compcode == COMPCODE_ORD) 2541 compcode = COMPCODE_TRUE; 2542 } 2543 else if (flag_trapping_math) 2544 { 2545 /* Check that the original operation and the optimized ones will trap 2546 under the same condition. */ 2547 bool ltrap = (lcompcode & COMPCODE_UNORD) == 0 2548 && (lcompcode != COMPCODE_EQ) 2549 && (lcompcode != COMPCODE_ORD); 2550 bool rtrap = (rcompcode & COMPCODE_UNORD) == 0 2551 && (rcompcode != COMPCODE_EQ) 2552 && (rcompcode != COMPCODE_ORD); 2553 bool trap = (compcode & COMPCODE_UNORD) == 0 2554 && (compcode != COMPCODE_EQ) 2555 && (compcode != COMPCODE_ORD); 2556 2557 /* In a short-circuited boolean expression the LHS might be 2558 such that the RHS, if evaluated, will never trap. For 2559 example, in ORD (x, y) && (x < y), we evaluate the RHS only 2560 if neither x nor y is NaN. (This is a mixed blessing: for 2561 example, the expression above will never trap, hence 2562 optimizing it to x < y would be invalid). */ 2563 if ((code == TRUTH_ORIF_EXPR && (lcompcode & COMPCODE_UNORD)) 2564 || (code == TRUTH_ANDIF_EXPR && !(lcompcode & COMPCODE_UNORD))) 2565 rtrap = false; 2566 2567 /* If the comparison was short-circuited, and only the RHS 2568 trapped, we may now generate a spurious trap. */ 2569 if (rtrap && !ltrap 2570 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR)) 2571 return NULL_TREE; 2572 2573 /* If we changed the conditions that cause a trap, we lose. */ 2574 if ((ltrap || rtrap) != trap) 2575 return NULL_TREE; 2576 } 2577 2578 if (compcode == COMPCODE_TRUE) 2579 return constant_boolean_node (true, truth_type); 2580 else if (compcode == COMPCODE_FALSE) 2581 return constant_boolean_node (false, truth_type); 2582 else 2583 return fold_build2 (compcode_to_comparison (compcode), 2584 truth_type, ll_arg, lr_arg); 2585} 2586 2587/* Return nonzero if CODE is a tree code that represents a truth value. */ 2588 2589static int 2590truth_value_p (enum tree_code code) 2591{ 2592 return (TREE_CODE_CLASS (code) == tcc_comparison 2593 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR 2594 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR 2595 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR); 2596} 2597 2598/* Return nonzero if two operands (typically of the same tree node) 2599 are necessarily equal. If either argument has side-effects this 2600 function returns zero. FLAGS modifies behavior as follows: 2601 2602 If OEP_ONLY_CONST is set, only return nonzero for constants. 2603 This function tests whether the operands are indistinguishable; 2604 it does not test whether they are equal using C's == operation. 2605 The distinction is important for IEEE floating point, because 2606 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and 2607 (2) two NaNs may be indistinguishable, but NaN!=NaN. 2608 2609 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself 2610 even though it may hold multiple values during a function. 2611 This is because a GCC tree node guarantees that nothing else is 2612 executed between the evaluation of its "operands" (which may often 2613 be evaluated in arbitrary order). Hence if the operands themselves 2614 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the 2615 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST 2616 unset means assuming isochronic (or instantaneous) tree equivalence. 2617 Unless comparing arbitrary expression trees, such as from different 2618 statements, this flag can usually be left unset. 2619 2620 If OEP_PURE_SAME is set, then pure functions with identical arguments 2621 are considered the same. It is used when the caller has other ways 2622 to ensure that global memory is unchanged in between. */ 2623 2624int 2625operand_equal_p (tree arg0, tree arg1, unsigned int flags) 2626{ 2627 /* If either is ERROR_MARK, they aren't equal. */ 2628 if (TREE_CODE (arg0) == ERROR_MARK || TREE_CODE (arg1) == ERROR_MARK) 2629 return 0; 2630 2631 /* If both types don't have the same signedness, then we can't consider 2632 them equal. We must check this before the STRIP_NOPS calls 2633 because they may change the signedness of the arguments. */ 2634 if (TYPE_UNSIGNED (TREE_TYPE (arg0)) != TYPE_UNSIGNED (TREE_TYPE (arg1))) 2635 return 0; 2636 2637 /* If both types don't have the same precision, then it is not safe 2638 to strip NOPs. */ 2639 if (TYPE_PRECISION (TREE_TYPE (arg0)) != TYPE_PRECISION (TREE_TYPE (arg1))) 2640 return 0; 2641 2642 STRIP_NOPS (arg0); 2643 STRIP_NOPS (arg1); 2644 2645 /* In case both args are comparisons but with different comparison 2646 code, try to swap the comparison operands of one arg to produce 2647 a match and compare that variant. */ 2648 if (TREE_CODE (arg0) != TREE_CODE (arg1) 2649 && COMPARISON_CLASS_P (arg0) 2650 && COMPARISON_CLASS_P (arg1)) 2651 { 2652 enum tree_code swap_code = swap_tree_comparison (TREE_CODE (arg1)); 2653 2654 if (TREE_CODE (arg0) == swap_code) 2655 return operand_equal_p (TREE_OPERAND (arg0, 0), 2656 TREE_OPERAND (arg1, 1), flags) 2657 && operand_equal_p (TREE_OPERAND (arg0, 1), 2658 TREE_OPERAND (arg1, 0), flags); 2659 } 2660 2661 if (TREE_CODE (arg0) != TREE_CODE (arg1) 2662 /* This is needed for conversions and for COMPONENT_REF. 2663 Might as well play it safe and always test this. */ 2664 || TREE_CODE (TREE_TYPE (arg0)) == ERROR_MARK 2665 || TREE_CODE (TREE_TYPE (arg1)) == ERROR_MARK 2666 || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1))) 2667 return 0; 2668 2669 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal. 2670 We don't care about side effects in that case because the SAVE_EXPR 2671 takes care of that for us. In all other cases, two expressions are 2672 equal if they have no side effects. If we have two identical 2673 expressions with side effects that should be treated the same due 2674 to the only side effects being identical SAVE_EXPR's, that will 2675 be detected in the recursive calls below. */ 2676 if (arg0 == arg1 && ! (flags & OEP_ONLY_CONST) 2677 && (TREE_CODE (arg0) == SAVE_EXPR 2678 || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1)))) 2679 return 1; 2680 2681 /* Next handle constant cases, those for which we can return 1 even 2682 if ONLY_CONST is set. */ 2683 if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1)) 2684 switch (TREE_CODE (arg0)) 2685 { 2686 case INTEGER_CST: 2687 return (! TREE_CONSTANT_OVERFLOW (arg0) 2688 && ! TREE_CONSTANT_OVERFLOW (arg1) 2689 && tree_int_cst_equal (arg0, arg1)); 2690 2691 case REAL_CST: 2692 return (! TREE_CONSTANT_OVERFLOW (arg0) 2693 && ! TREE_CONSTANT_OVERFLOW (arg1) 2694 && REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0), 2695 TREE_REAL_CST (arg1))); 2696 2697 case VECTOR_CST: 2698 { 2699 tree v1, v2; 2700 2701 if (TREE_CONSTANT_OVERFLOW (arg0) 2702 || TREE_CONSTANT_OVERFLOW (arg1)) 2703 return 0; 2704 2705 v1 = TREE_VECTOR_CST_ELTS (arg0); 2706 v2 = TREE_VECTOR_CST_ELTS (arg1); 2707 while (v1 && v2) 2708 { 2709 if (!operand_equal_p (TREE_VALUE (v1), TREE_VALUE (v2), 2710 flags)) 2711 return 0; 2712 v1 = TREE_CHAIN (v1); 2713 v2 = TREE_CHAIN (v2); 2714 } 2715 2716 return v1 == v2; 2717 } 2718 2719 case COMPLEX_CST: 2720 return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1), 2721 flags) 2722 && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1), 2723 flags)); 2724 2725 case STRING_CST: 2726 return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1) 2727 && ! memcmp (TREE_STRING_POINTER (arg0), 2728 TREE_STRING_POINTER (arg1), 2729 TREE_STRING_LENGTH (arg0))); 2730 2731 case ADDR_EXPR: 2732 return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 2733 0); 2734 default: 2735 break; 2736 } 2737 2738 if (flags & OEP_ONLY_CONST) 2739 return 0; 2740 2741/* Define macros to test an operand from arg0 and arg1 for equality and a 2742 variant that allows null and views null as being different from any 2743 non-null value. In the latter case, if either is null, the both 2744 must be; otherwise, do the normal comparison. */ 2745#define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \ 2746 TREE_OPERAND (arg1, N), flags) 2747 2748#define OP_SAME_WITH_NULL(N) \ 2749 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \ 2750 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N)) 2751 2752 switch (TREE_CODE_CLASS (TREE_CODE (arg0))) 2753 { 2754 case tcc_unary: 2755 /* Two conversions are equal only if signedness and modes match. */ 2756 switch (TREE_CODE (arg0)) 2757 { 2758 case NOP_EXPR: 2759 case CONVERT_EXPR: 2760 case FIX_CEIL_EXPR: 2761 case FIX_TRUNC_EXPR: 2762 case FIX_FLOOR_EXPR: 2763 case FIX_ROUND_EXPR: 2764 if (TYPE_UNSIGNED (TREE_TYPE (arg0)) 2765 != TYPE_UNSIGNED (TREE_TYPE (arg1))) 2766 return 0; 2767 break; 2768 default: 2769 break; 2770 } 2771 2772 return OP_SAME (0); 2773 2774 2775 case tcc_comparison: 2776 case tcc_binary: 2777 if (OP_SAME (0) && OP_SAME (1)) 2778 return 1; 2779 2780 /* For commutative ops, allow the other order. */ 2781 return (commutative_tree_code (TREE_CODE (arg0)) 2782 && operand_equal_p (TREE_OPERAND (arg0, 0), 2783 TREE_OPERAND (arg1, 1), flags) 2784 && operand_equal_p (TREE_OPERAND (arg0, 1), 2785 TREE_OPERAND (arg1, 0), flags)); 2786 2787 case tcc_reference: 2788 /* If either of the pointer (or reference) expressions we are 2789 dereferencing contain a side effect, these cannot be equal. */ 2790 if (TREE_SIDE_EFFECTS (arg0) 2791 || TREE_SIDE_EFFECTS (arg1)) 2792 return 0; 2793 2794 switch (TREE_CODE (arg0)) 2795 { 2796 case INDIRECT_REF: 2797 case ALIGN_INDIRECT_REF: 2798 case MISALIGNED_INDIRECT_REF: 2799 case REALPART_EXPR: 2800 case IMAGPART_EXPR: 2801 return OP_SAME (0); 2802 2803 case ARRAY_REF: 2804 case ARRAY_RANGE_REF: 2805 /* Operands 2 and 3 may be null. */ 2806 return (OP_SAME (0) 2807 && OP_SAME (1) 2808 && OP_SAME_WITH_NULL (2) 2809 && OP_SAME_WITH_NULL (3)); 2810 2811 case COMPONENT_REF: 2812 /* Handle operand 2 the same as for ARRAY_REF. Operand 0 2813 may be NULL when we're called to compare MEM_EXPRs. */ 2814 return OP_SAME_WITH_NULL (0) 2815 && OP_SAME (1) 2816 && OP_SAME_WITH_NULL (2); 2817 2818 case BIT_FIELD_REF: 2819 return OP_SAME (0) && OP_SAME (1) && OP_SAME (2); 2820 2821 default: 2822 return 0; 2823 } 2824 2825 case tcc_expression: 2826 switch (TREE_CODE (arg0)) 2827 { 2828 case ADDR_EXPR: 2829 case TRUTH_NOT_EXPR: 2830 return OP_SAME (0); 2831 2832 case TRUTH_ANDIF_EXPR: 2833 case TRUTH_ORIF_EXPR: 2834 return OP_SAME (0) && OP_SAME (1); 2835 2836 case TRUTH_AND_EXPR: 2837 case TRUTH_OR_EXPR: 2838 case TRUTH_XOR_EXPR: 2839 if (OP_SAME (0) && OP_SAME (1)) 2840 return 1; 2841 2842 /* Otherwise take into account this is a commutative operation. */ 2843 return (operand_equal_p (TREE_OPERAND (arg0, 0), 2844 TREE_OPERAND (arg1, 1), flags) 2845 && operand_equal_p (TREE_OPERAND (arg0, 1), 2846 TREE_OPERAND (arg1, 0), flags)); 2847 2848 case CALL_EXPR: 2849 /* If the CALL_EXPRs call different functions, then they 2850 clearly can not be equal. */ 2851 if (!OP_SAME (0)) 2852 return 0; 2853 2854 { 2855 unsigned int cef = call_expr_flags (arg0); 2856 if (flags & OEP_PURE_SAME) 2857 cef &= ECF_CONST | ECF_PURE; 2858 else 2859 cef &= ECF_CONST; 2860 if (!cef) 2861 return 0; 2862 } 2863 2864 /* Now see if all the arguments are the same. operand_equal_p 2865 does not handle TREE_LIST, so we walk the operands here 2866 feeding them to operand_equal_p. */ 2867 arg0 = TREE_OPERAND (arg0, 1); 2868 arg1 = TREE_OPERAND (arg1, 1); 2869 while (arg0 && arg1) 2870 { 2871 if (! operand_equal_p (TREE_VALUE (arg0), TREE_VALUE (arg1), 2872 flags)) 2873 return 0; 2874 2875 arg0 = TREE_CHAIN (arg0); 2876 arg1 = TREE_CHAIN (arg1); 2877 } 2878 2879 /* If we get here and both argument lists are exhausted 2880 then the CALL_EXPRs are equal. */ 2881 return ! (arg0 || arg1); 2882 2883 default: 2884 return 0; 2885 } 2886 2887 case tcc_declaration: 2888 /* Consider __builtin_sqrt equal to sqrt. */ 2889 return (TREE_CODE (arg0) == FUNCTION_DECL 2890 && DECL_BUILT_IN (arg0) && DECL_BUILT_IN (arg1) 2891 && DECL_BUILT_IN_CLASS (arg0) == DECL_BUILT_IN_CLASS (arg1) 2892 && DECL_FUNCTION_CODE (arg0) == DECL_FUNCTION_CODE (arg1)); 2893 2894 default: 2895 return 0; 2896 } 2897 2898#undef OP_SAME 2899#undef OP_SAME_WITH_NULL 2900} 2901 2902/* Similar to operand_equal_p, but see if ARG0 might have been made by 2903 shorten_compare from ARG1 when ARG1 was being compared with OTHER. 2904 2905 When in doubt, return 0. */ 2906 2907static int 2908operand_equal_for_comparison_p (tree arg0, tree arg1, tree other) 2909{ 2910 int unsignedp1, unsignedpo; 2911 tree primarg0, primarg1, primother; 2912 unsigned int correct_width; 2913 2914 if (operand_equal_p (arg0, arg1, 0)) 2915 return 1; 2916 2917 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)) 2918 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1))) 2919 return 0; 2920 2921 /* Discard any conversions that don't change the modes of ARG0 and ARG1 2922 and see if the inner values are the same. This removes any 2923 signedness comparison, which doesn't matter here. */ 2924 primarg0 = arg0, primarg1 = arg1; 2925 STRIP_NOPS (primarg0); 2926 STRIP_NOPS (primarg1); 2927 if (operand_equal_p (primarg0, primarg1, 0)) 2928 return 1; 2929 2930 /* Duplicate what shorten_compare does to ARG1 and see if that gives the 2931 actual comparison operand, ARG0. 2932 2933 First throw away any conversions to wider types 2934 already present in the operands. */ 2935 2936 primarg1 = get_narrower (arg1, &unsignedp1); 2937 primother = get_narrower (other, &unsignedpo); 2938 2939 correct_width = TYPE_PRECISION (TREE_TYPE (arg1)); 2940 if (unsignedp1 == unsignedpo 2941 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width 2942 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width) 2943 { 2944 tree type = TREE_TYPE (arg0); 2945 2946 /* Make sure shorter operand is extended the right way 2947 to match the longer operand. */ 2948 primarg1 = fold_convert (lang_hooks.types.signed_or_unsigned_type 2949 (unsignedp1, TREE_TYPE (primarg1)), primarg1); 2950 2951 if (operand_equal_p (arg0, fold_convert (type, primarg1), 0)) 2952 return 1; 2953 } 2954 2955 return 0; 2956} 2957 2958/* See if ARG is an expression that is either a comparison or is performing 2959 arithmetic on comparisons. The comparisons must only be comparing 2960 two different values, which will be stored in *CVAL1 and *CVAL2; if 2961 they are nonzero it means that some operands have already been found. 2962 No variables may be used anywhere else in the expression except in the 2963 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around 2964 the expression and save_expr needs to be called with CVAL1 and CVAL2. 2965 2966 If this is true, return 1. Otherwise, return zero. */ 2967 2968static int 2969twoval_comparison_p (tree arg, tree *cval1, tree *cval2, int *save_p) 2970{ 2971 enum tree_code code = TREE_CODE (arg); 2972 enum tree_code_class class = TREE_CODE_CLASS (code); 2973 2974 /* We can handle some of the tcc_expression cases here. */ 2975 if (class == tcc_expression && code == TRUTH_NOT_EXPR) 2976 class = tcc_unary; 2977 else if (class == tcc_expression 2978 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR 2979 || code == COMPOUND_EXPR)) 2980 class = tcc_binary; 2981 2982 else if (class == tcc_expression && code == SAVE_EXPR 2983 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0))) 2984 { 2985 /* If we've already found a CVAL1 or CVAL2, this expression is 2986 two complex to handle. */ 2987 if (*cval1 || *cval2) 2988 return 0; 2989 2990 class = tcc_unary; 2991 *save_p = 1; 2992 } 2993 2994 switch (class) 2995 { 2996 case tcc_unary: 2997 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p); 2998 2999 case tcc_binary: 3000 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p) 3001 && twoval_comparison_p (TREE_OPERAND (arg, 1), 3002 cval1, cval2, save_p)); 3003 3004 case tcc_constant: 3005 return 1; 3006 3007 case tcc_expression: 3008 if (code == COND_EXPR) 3009 return (twoval_comparison_p (TREE_OPERAND (arg, 0), 3010 cval1, cval2, save_p) 3011 && twoval_comparison_p (TREE_OPERAND (arg, 1), 3012 cval1, cval2, save_p) 3013 && twoval_comparison_p (TREE_OPERAND (arg, 2), 3014 cval1, cval2, save_p)); 3015 return 0; 3016 3017 case tcc_comparison: 3018 /* First see if we can handle the first operand, then the second. For 3019 the second operand, we know *CVAL1 can't be zero. It must be that 3020 one side of the comparison is each of the values; test for the 3021 case where this isn't true by failing if the two operands 3022 are the same. */ 3023 3024 if (operand_equal_p (TREE_OPERAND (arg, 0), 3025 TREE_OPERAND (arg, 1), 0)) 3026 return 0; 3027 3028 if (*cval1 == 0) 3029 *cval1 = TREE_OPERAND (arg, 0); 3030 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0)) 3031 ; 3032 else if (*cval2 == 0) 3033 *cval2 = TREE_OPERAND (arg, 0); 3034 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0)) 3035 ; 3036 else 3037 return 0; 3038 3039 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0)) 3040 ; 3041 else if (*cval2 == 0) 3042 *cval2 = TREE_OPERAND (arg, 1); 3043 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0)) 3044 ; 3045 else 3046 return 0; 3047 3048 return 1; 3049 3050 default: 3051 return 0; 3052 } 3053} 3054 3055/* ARG is a tree that is known to contain just arithmetic operations and 3056 comparisons. Evaluate the operations in the tree substituting NEW0 for 3057 any occurrence of OLD0 as an operand of a comparison and likewise for 3058 NEW1 and OLD1. */ 3059 3060static tree 3061eval_subst (tree arg, tree old0, tree new0, tree old1, tree new1) 3062{ 3063 tree type = TREE_TYPE (arg); 3064 enum tree_code code = TREE_CODE (arg); 3065 enum tree_code_class class = TREE_CODE_CLASS (code); 3066 3067 /* We can handle some of the tcc_expression cases here. */ 3068 if (class == tcc_expression && code == TRUTH_NOT_EXPR) 3069 class = tcc_unary; 3070 else if (class == tcc_expression 3071 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR)) 3072 class = tcc_binary; 3073 3074 switch (class) 3075 { 3076 case tcc_unary: 3077 return fold_build1 (code, type, 3078 eval_subst (TREE_OPERAND (arg, 0), 3079 old0, new0, old1, new1)); 3080 3081 case tcc_binary: 3082 return fold_build2 (code, type, 3083 eval_subst (TREE_OPERAND (arg, 0), 3084 old0, new0, old1, new1), 3085 eval_subst (TREE_OPERAND (arg, 1), 3086 old0, new0, old1, new1)); 3087 3088 case tcc_expression: 3089 switch (code) 3090 { 3091 case SAVE_EXPR: 3092 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1); 3093 3094 case COMPOUND_EXPR: 3095 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1); 3096 3097 case COND_EXPR: 3098 return fold_build3 (code, type, 3099 eval_subst (TREE_OPERAND (arg, 0), 3100 old0, new0, old1, new1), 3101 eval_subst (TREE_OPERAND (arg, 1), 3102 old0, new0, old1, new1), 3103 eval_subst (TREE_OPERAND (arg, 2), 3104 old0, new0, old1, new1)); 3105 default: 3106 break; 3107 } 3108 /* Fall through - ??? */ 3109 3110 case tcc_comparison: 3111 { 3112 tree arg0 = TREE_OPERAND (arg, 0); 3113 tree arg1 = TREE_OPERAND (arg, 1); 3114 3115 /* We need to check both for exact equality and tree equality. The 3116 former will be true if the operand has a side-effect. In that 3117 case, we know the operand occurred exactly once. */ 3118 3119 if (arg0 == old0 || operand_equal_p (arg0, old0, 0)) 3120 arg0 = new0; 3121 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0)) 3122 arg0 = new1; 3123 3124 if (arg1 == old0 || operand_equal_p (arg1, old0, 0)) 3125 arg1 = new0; 3126 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0)) 3127 arg1 = new1; 3128 3129 return fold_build2 (code, type, arg0, arg1); 3130 } 3131 3132 default: 3133 return arg; 3134 } 3135} 3136 3137/* Return a tree for the case when the result of an expression is RESULT 3138 converted to TYPE and OMITTED was previously an operand of the expression 3139 but is now not needed (e.g., we folded OMITTED * 0). 3140 3141 If OMITTED has side effects, we must evaluate it. Otherwise, just do 3142 the conversion of RESULT to TYPE. */ 3143 3144tree 3145omit_one_operand (tree type, tree result, tree omitted) 3146{ 3147 tree t = fold_convert (type, result); 3148 3149 if (TREE_SIDE_EFFECTS (omitted)) 3150 return build2 (COMPOUND_EXPR, type, fold_ignored_result (omitted), t); 3151 3152 return non_lvalue (t); 3153} 3154 3155/* Similar, but call pedantic_non_lvalue instead of non_lvalue. */ 3156 3157static tree 3158pedantic_omit_one_operand (tree type, tree result, tree omitted) 3159{ 3160 tree t = fold_convert (type, result); 3161 3162 if (TREE_SIDE_EFFECTS (omitted)) 3163 return build2 (COMPOUND_EXPR, type, fold_ignored_result (omitted), t); 3164 3165 return pedantic_non_lvalue (t); 3166} 3167 3168/* Return a tree for the case when the result of an expression is RESULT 3169 converted to TYPE and OMITTED1 and OMITTED2 were previously operands 3170 of the expression but are now not needed. 3171 3172 If OMITTED1 or OMITTED2 has side effects, they must be evaluated. 3173 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is 3174 evaluated before OMITTED2. Otherwise, if neither has side effects, 3175 just do the conversion of RESULT to TYPE. */ 3176 3177tree 3178omit_two_operands (tree type, tree result, tree omitted1, tree omitted2) 3179{ 3180 tree t = fold_convert (type, result); 3181 3182 if (TREE_SIDE_EFFECTS (omitted2)) 3183 t = build2 (COMPOUND_EXPR, type, omitted2, t); 3184 if (TREE_SIDE_EFFECTS (omitted1)) 3185 t = build2 (COMPOUND_EXPR, type, omitted1, t); 3186 3187 return TREE_CODE (t) != COMPOUND_EXPR ? non_lvalue (t) : t; 3188} 3189 3190 3191/* Return a simplified tree node for the truth-negation of ARG. This 3192 never alters ARG itself. We assume that ARG is an operation that 3193 returns a truth value (0 or 1). 3194 3195 FIXME: one would think we would fold the result, but it causes 3196 problems with the dominator optimizer. */ 3197 3198tree 3199fold_truth_not_expr (tree arg) 3200{ 3201 tree type = TREE_TYPE (arg); 3202 enum tree_code code = TREE_CODE (arg); 3203 3204 /* If this is a comparison, we can simply invert it, except for 3205 floating-point non-equality comparisons, in which case we just 3206 enclose a TRUTH_NOT_EXPR around what we have. */ 3207 3208 if (TREE_CODE_CLASS (code) == tcc_comparison) 3209 { 3210 tree op_type = TREE_TYPE (TREE_OPERAND (arg, 0)); 3211 if (FLOAT_TYPE_P (op_type) 3212 && flag_trapping_math 3213 && code != ORDERED_EXPR && code != UNORDERED_EXPR 3214 && code != NE_EXPR && code != EQ_EXPR) 3215 return NULL_TREE; 3216 else 3217 { 3218 code = invert_tree_comparison (code, 3219 HONOR_NANS (TYPE_MODE (op_type))); 3220 if (code == ERROR_MARK) 3221 return NULL_TREE; 3222 else 3223 return build2 (code, type, 3224 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1)); 3225 } 3226 } 3227 3228 switch (code) 3229 { 3230 case INTEGER_CST: 3231 return constant_boolean_node (integer_zerop (arg), type); 3232 3233 case TRUTH_AND_EXPR: 3234 return build2 (TRUTH_OR_EXPR, type, 3235 invert_truthvalue (TREE_OPERAND (arg, 0)), 3236 invert_truthvalue (TREE_OPERAND (arg, 1))); 3237 3238 case TRUTH_OR_EXPR: 3239 return build2 (TRUTH_AND_EXPR, type, 3240 invert_truthvalue (TREE_OPERAND (arg, 0)), 3241 invert_truthvalue (TREE_OPERAND (arg, 1))); 3242 3243 case TRUTH_XOR_EXPR: 3244 /* Here we can invert either operand. We invert the first operand 3245 unless the second operand is a TRUTH_NOT_EXPR in which case our 3246 result is the XOR of the first operand with the inside of the 3247 negation of the second operand. */ 3248 3249 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR) 3250 return build2 (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0), 3251 TREE_OPERAND (TREE_OPERAND (arg, 1), 0)); 3252 else 3253 return build2 (TRUTH_XOR_EXPR, type, 3254 invert_truthvalue (TREE_OPERAND (arg, 0)), 3255 TREE_OPERAND (arg, 1)); 3256 3257 case TRUTH_ANDIF_EXPR: 3258 return build2 (TRUTH_ORIF_EXPR, type, 3259 invert_truthvalue (TREE_OPERAND (arg, 0)), 3260 invert_truthvalue (TREE_OPERAND (arg, 1))); 3261 3262 case TRUTH_ORIF_EXPR: 3263 return build2 (TRUTH_ANDIF_EXPR, type, 3264 invert_truthvalue (TREE_OPERAND (arg, 0)), 3265 invert_truthvalue (TREE_OPERAND (arg, 1))); 3266 3267 case TRUTH_NOT_EXPR: 3268 return TREE_OPERAND (arg, 0); 3269 3270 case COND_EXPR: 3271 { 3272 tree arg1 = TREE_OPERAND (arg, 1); 3273 tree arg2 = TREE_OPERAND (arg, 2); 3274 /* A COND_EXPR may have a throw as one operand, which 3275 then has void type. Just leave void operands 3276 as they are. */ 3277 return build3 (COND_EXPR, type, TREE_OPERAND (arg, 0), 3278 VOID_TYPE_P (TREE_TYPE (arg1)) 3279 ? arg1 : invert_truthvalue (arg1), 3280 VOID_TYPE_P (TREE_TYPE (arg2)) 3281 ? arg2 : invert_truthvalue (arg2)); 3282 } 3283 3284 case COMPOUND_EXPR: 3285 return build2 (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0), 3286 invert_truthvalue (TREE_OPERAND (arg, 1))); 3287 3288 case NON_LVALUE_EXPR: 3289 return invert_truthvalue (TREE_OPERAND (arg, 0)); 3290 3291 case NOP_EXPR: 3292 if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE) 3293 return build1 (TRUTH_NOT_EXPR, type, arg); 3294 3295 case CONVERT_EXPR: 3296 case FLOAT_EXPR: 3297 return build1 (TREE_CODE (arg), type, 3298 invert_truthvalue (TREE_OPERAND (arg, 0))); 3299 3300 case BIT_AND_EXPR: 3301 if (!integer_onep (TREE_OPERAND (arg, 1))) 3302 break; 3303 return build2 (EQ_EXPR, type, arg, 3304 build_int_cst (type, 0)); 3305 3306 case SAVE_EXPR: 3307 return build1 (TRUTH_NOT_EXPR, type, arg); 3308 3309 case CLEANUP_POINT_EXPR: 3310 return build1 (CLEANUP_POINT_EXPR, type, 3311 invert_truthvalue (TREE_OPERAND (arg, 0))); 3312 3313 default: 3314 break; 3315 } 3316 3317 return NULL_TREE; 3318} 3319 3320/* Return a simplified tree node for the truth-negation of ARG. This 3321 never alters ARG itself. We assume that ARG is an operation that 3322 returns a truth value (0 or 1). 3323 3324 FIXME: one would think we would fold the result, but it causes 3325 problems with the dominator optimizer. */ 3326 3327tree 3328invert_truthvalue (tree arg) 3329{ 3330 tree tem; 3331 3332 if (TREE_CODE (arg) == ERROR_MARK) 3333 return arg; 3334 3335 tem = fold_truth_not_expr (arg); 3336 if (!tem) 3337 tem = build1 (TRUTH_NOT_EXPR, TREE_TYPE (arg), arg); 3338 3339 return tem; 3340} 3341 3342/* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both 3343 operands are another bit-wise operation with a common input. If so, 3344 distribute the bit operations to save an operation and possibly two if 3345 constants are involved. For example, convert 3346 (A | B) & (A | C) into A | (B & C) 3347 Further simplification will occur if B and C are constants. 3348 3349 If this optimization cannot be done, 0 will be returned. */ 3350 3351static tree 3352distribute_bit_expr (enum tree_code code, tree type, tree arg0, tree arg1) 3353{ 3354 tree common; 3355 tree left, right; 3356 3357 if (TREE_CODE (arg0) != TREE_CODE (arg1) 3358 || TREE_CODE (arg0) == code 3359 || (TREE_CODE (arg0) != BIT_AND_EXPR 3360 && TREE_CODE (arg0) != BIT_IOR_EXPR)) 3361 return 0; 3362 3363 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)) 3364 { 3365 common = TREE_OPERAND (arg0, 0); 3366 left = TREE_OPERAND (arg0, 1); 3367 right = TREE_OPERAND (arg1, 1); 3368 } 3369 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0)) 3370 { 3371 common = TREE_OPERAND (arg0, 0); 3372 left = TREE_OPERAND (arg0, 1); 3373 right = TREE_OPERAND (arg1, 0); 3374 } 3375 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0)) 3376 { 3377 common = TREE_OPERAND (arg0, 1); 3378 left = TREE_OPERAND (arg0, 0); 3379 right = TREE_OPERAND (arg1, 1); 3380 } 3381 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0)) 3382 { 3383 common = TREE_OPERAND (arg0, 1); 3384 left = TREE_OPERAND (arg0, 0); 3385 right = TREE_OPERAND (arg1, 0); 3386 } 3387 else 3388 return 0; 3389 3390 return fold_build2 (TREE_CODE (arg0), type, common, 3391 fold_build2 (code, type, left, right)); 3392} 3393 3394/* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation 3395 with code CODE. This optimization is unsafe. */ 3396static tree 3397distribute_real_division (enum tree_code code, tree type, tree arg0, tree arg1) 3398{ 3399 bool mul0 = TREE_CODE (arg0) == MULT_EXPR; 3400 bool mul1 = TREE_CODE (arg1) == MULT_EXPR; 3401 3402 /* (A / C) +- (B / C) -> (A +- B) / C. */ 3403 if (mul0 == mul1 3404 && operand_equal_p (TREE_OPERAND (arg0, 1), 3405 TREE_OPERAND (arg1, 1), 0)) 3406 return fold_build2 (mul0 ? MULT_EXPR : RDIV_EXPR, type, 3407 fold_build2 (code, type, 3408 TREE_OPERAND (arg0, 0), 3409 TREE_OPERAND (arg1, 0)), 3410 TREE_OPERAND (arg0, 1)); 3411 3412 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */ 3413 if (operand_equal_p (TREE_OPERAND (arg0, 0), 3414 TREE_OPERAND (arg1, 0), 0) 3415 && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST 3416 && TREE_CODE (TREE_OPERAND (arg1, 1)) == REAL_CST) 3417 { 3418 REAL_VALUE_TYPE r0, r1; 3419 r0 = TREE_REAL_CST (TREE_OPERAND (arg0, 1)); 3420 r1 = TREE_REAL_CST (TREE_OPERAND (arg1, 1)); 3421 if (!mul0) 3422 real_arithmetic (&r0, RDIV_EXPR, &dconst1, &r0); 3423 if (!mul1) 3424 real_arithmetic (&r1, RDIV_EXPR, &dconst1, &r1); 3425 real_arithmetic (&r0, code, &r0, &r1); 3426 return fold_build2 (MULT_EXPR, type, 3427 TREE_OPERAND (arg0, 0), 3428 build_real (type, r0)); 3429 } 3430 3431 return NULL_TREE; 3432} 3433 3434/* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER 3435 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */ 3436 3437static tree 3438make_bit_field_ref (tree inner, tree type, int bitsize, int bitpos, 3439 int unsignedp) 3440{ 3441 tree result; 3442 3443 if (bitpos == 0) 3444 { 3445 tree size = TYPE_SIZE (TREE_TYPE (inner)); 3446 if ((INTEGRAL_TYPE_P (TREE_TYPE (inner)) 3447 || POINTER_TYPE_P (TREE_TYPE (inner))) 3448 && host_integerp (size, 0) 3449 && tree_low_cst (size, 0) == bitsize) 3450 return fold_convert (type, inner); 3451 } 3452 3453 result = build3 (BIT_FIELD_REF, type, inner, 3454 size_int (bitsize), bitsize_int (bitpos)); 3455 3456 BIT_FIELD_REF_UNSIGNED (result) = unsignedp; 3457 3458 return result; 3459} 3460 3461/* Optimize a bit-field compare. 3462 3463 There are two cases: First is a compare against a constant and the 3464 second is a comparison of two items where the fields are at the same 3465 bit position relative to the start of a chunk (byte, halfword, word) 3466 large enough to contain it. In these cases we can avoid the shift 3467 implicit in bitfield extractions. 3468 3469 For constants, we emit a compare of the shifted constant with the 3470 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being 3471 compared. For two fields at the same position, we do the ANDs with the 3472 similar mask and compare the result of the ANDs. 3473 3474 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR. 3475 COMPARE_TYPE is the type of the comparison, and LHS and RHS 3476 are the left and right operands of the comparison, respectively. 3477 3478 If the optimization described above can be done, we return the resulting 3479 tree. Otherwise we return zero. */ 3480 3481static tree 3482optimize_bit_field_compare (enum tree_code code, tree compare_type, 3483 tree lhs, tree rhs) 3484{ 3485 HOST_WIDE_INT lbitpos, lbitsize, rbitpos, rbitsize, nbitpos, nbitsize; 3486 tree type = TREE_TYPE (lhs); 3487 tree signed_type, unsigned_type; 3488 int const_p = TREE_CODE (rhs) == INTEGER_CST; 3489 enum machine_mode lmode, rmode, nmode; 3490 int lunsignedp, runsignedp; 3491 int lvolatilep = 0, rvolatilep = 0; 3492 tree linner, rinner = NULL_TREE; 3493 tree mask; 3494 tree offset; 3495 3496 /* Get all the information about the extractions being done. If the bit size 3497 if the same as the size of the underlying object, we aren't doing an 3498 extraction at all and so can do nothing. We also don't want to 3499 do anything if the inner expression is a PLACEHOLDER_EXPR since we 3500 then will no longer be able to replace it. */ 3501 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode, 3502 &lunsignedp, &lvolatilep, false); 3503 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0 3504 || offset != 0 || TREE_CODE (linner) == PLACEHOLDER_EXPR) 3505 return 0; 3506 3507 if (!const_p) 3508 { 3509 /* If this is not a constant, we can only do something if bit positions, 3510 sizes, and signedness are the same. */ 3511 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode, 3512 &runsignedp, &rvolatilep, false); 3513 3514 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize 3515 || lunsignedp != runsignedp || offset != 0 3516 || TREE_CODE (rinner) == PLACEHOLDER_EXPR) 3517 return 0; 3518 } 3519 3520 /* See if we can find a mode to refer to this field. We should be able to, 3521 but fail if we can't. */ 3522 nmode = get_best_mode (lbitsize, lbitpos, 3523 const_p ? TYPE_ALIGN (TREE_TYPE (linner)) 3524 : MIN (TYPE_ALIGN (TREE_TYPE (linner)), 3525 TYPE_ALIGN (TREE_TYPE (rinner))), 3526 word_mode, lvolatilep || rvolatilep); 3527 if (nmode == VOIDmode) 3528 return 0; 3529 3530 /* Set signed and unsigned types of the precision of this mode for the 3531 shifts below. */ 3532 signed_type = lang_hooks.types.type_for_mode (nmode, 0); 3533 unsigned_type = lang_hooks.types.type_for_mode (nmode, 1); 3534 3535 /* Compute the bit position and size for the new reference and our offset 3536 within it. If the new reference is the same size as the original, we 3537 won't optimize anything, so return zero. */ 3538 nbitsize = GET_MODE_BITSIZE (nmode); 3539 nbitpos = lbitpos & ~ (nbitsize - 1); 3540 lbitpos -= nbitpos; 3541 if (nbitsize == lbitsize) 3542 return 0; 3543 3544 if (BYTES_BIG_ENDIAN) 3545 lbitpos = nbitsize - lbitsize - lbitpos; 3546 3547 /* Make the mask to be used against the extracted field. */ 3548 mask = build_int_cst (unsigned_type, -1); 3549 mask = force_fit_type (mask, 0, false, false); 3550 mask = fold_convert (unsigned_type, mask); 3551 mask = const_binop (LSHIFT_EXPR, mask, size_int (nbitsize - lbitsize), 0); 3552 mask = const_binop (RSHIFT_EXPR, mask, 3553 size_int (nbitsize - lbitsize - lbitpos), 0); 3554 3555 if (! const_p) 3556 /* If not comparing with constant, just rework the comparison 3557 and return. */ 3558 return build2 (code, compare_type, 3559 build2 (BIT_AND_EXPR, unsigned_type, 3560 make_bit_field_ref (linner, unsigned_type, 3561 nbitsize, nbitpos, 1), 3562 mask), 3563 build2 (BIT_AND_EXPR, unsigned_type, 3564 make_bit_field_ref (rinner, unsigned_type, 3565 nbitsize, nbitpos, 1), 3566 mask)); 3567 3568 /* Otherwise, we are handling the constant case. See if the constant is too 3569 big for the field. Warn and return a tree of for 0 (false) if so. We do 3570 this not only for its own sake, but to avoid having to test for this 3571 error case below. If we didn't, we might generate wrong code. 3572 3573 For unsigned fields, the constant shifted right by the field length should 3574 be all zero. For signed fields, the high-order bits should agree with 3575 the sign bit. */ 3576 3577 if (lunsignedp) 3578 { 3579 if (! integer_zerop (const_binop (RSHIFT_EXPR, 3580 fold_convert (unsigned_type, rhs), 3581 size_int (lbitsize), 0))) 3582 { 3583 warning (0, "comparison is always %d due to width of bit-field", 3584 code == NE_EXPR); 3585 return constant_boolean_node (code == NE_EXPR, compare_type); 3586 } 3587 } 3588 else 3589 { 3590 tree tem = const_binop (RSHIFT_EXPR, fold_convert (signed_type, rhs), 3591 size_int (lbitsize - 1), 0); 3592 if (! integer_zerop (tem) && ! integer_all_onesp (tem)) 3593 { 3594 warning (0, "comparison is always %d due to width of bit-field", 3595 code == NE_EXPR); 3596 return constant_boolean_node (code == NE_EXPR, compare_type); 3597 } 3598 } 3599 3600 /* Single-bit compares should always be against zero. */ 3601 if (lbitsize == 1 && ! integer_zerop (rhs)) 3602 { 3603 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR; 3604 rhs = build_int_cst (type, 0); 3605 } 3606 3607 /* Make a new bitfield reference, shift the constant over the 3608 appropriate number of bits and mask it with the computed mask 3609 (in case this was a signed field). If we changed it, make a new one. */ 3610 lhs = make_bit_field_ref (linner, unsigned_type, nbitsize, nbitpos, 1); 3611 if (lvolatilep) 3612 { 3613 TREE_SIDE_EFFECTS (lhs) = 1; 3614 TREE_THIS_VOLATILE (lhs) = 1; 3615 } 3616 3617 rhs = const_binop (BIT_AND_EXPR, 3618 const_binop (LSHIFT_EXPR, 3619 fold_convert (unsigned_type, rhs), 3620 size_int (lbitpos), 0), 3621 mask, 0); 3622 3623 return build2 (code, compare_type, 3624 build2 (BIT_AND_EXPR, unsigned_type, lhs, mask), 3625 rhs); 3626} 3627 3628/* Subroutine for fold_truthop: decode a field reference. 3629 3630 If EXP is a comparison reference, we return the innermost reference. 3631 3632 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is 3633 set to the starting bit number. 3634 3635 If the innermost field can be completely contained in a mode-sized 3636 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode. 3637 3638 *PVOLATILEP is set to 1 if the any expression encountered is volatile; 3639 otherwise it is not changed. 3640 3641 *PUNSIGNEDP is set to the signedness of the field. 3642 3643 *PMASK is set to the mask used. This is either contained in a 3644 BIT_AND_EXPR or derived from the width of the field. 3645 3646 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any. 3647 3648 Return 0 if this is not a component reference or is one that we can't 3649 do anything with. */ 3650 3651static tree 3652decode_field_reference (tree exp, HOST_WIDE_INT *pbitsize, 3653 HOST_WIDE_INT *pbitpos, enum machine_mode *pmode, 3654 int *punsignedp, int *pvolatilep, 3655 tree *pmask, tree *pand_mask) 3656{ 3657 tree outer_type = 0; 3658 tree and_mask = 0; 3659 tree mask, inner, offset; 3660 tree unsigned_type; 3661 unsigned int precision; 3662 3663 /* All the optimizations using this function assume integer fields. 3664 There are problems with FP fields since the type_for_size call 3665 below can fail for, e.g., XFmode. */ 3666 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp))) 3667 return 0; 3668 3669 /* We are interested in the bare arrangement of bits, so strip everything 3670 that doesn't affect the machine mode. However, record the type of the 3671 outermost expression if it may matter below. */ 3672 if (TREE_CODE (exp) == NOP_EXPR 3673 || TREE_CODE (exp) == CONVERT_EXPR 3674 || TREE_CODE (exp) == NON_LVALUE_EXPR) 3675 outer_type = TREE_TYPE (exp); 3676 STRIP_NOPS (exp); 3677 3678 if (TREE_CODE (exp) == BIT_AND_EXPR) 3679 { 3680 and_mask = TREE_OPERAND (exp, 1); 3681 exp = TREE_OPERAND (exp, 0); 3682 STRIP_NOPS (exp); STRIP_NOPS (and_mask); 3683 if (TREE_CODE (and_mask) != INTEGER_CST) 3684 return 0; 3685 } 3686 3687 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode, 3688 punsignedp, pvolatilep, false); 3689 if ((inner == exp && and_mask == 0) 3690 || *pbitsize < 0 || offset != 0 3691 || TREE_CODE (inner) == PLACEHOLDER_EXPR) 3692 return 0; 3693 3694 /* If the number of bits in the reference is the same as the bitsize of 3695 the outer type, then the outer type gives the signedness. Otherwise 3696 (in case of a small bitfield) the signedness is unchanged. */ 3697 if (outer_type && *pbitsize == TYPE_PRECISION (outer_type)) 3698 *punsignedp = TYPE_UNSIGNED (outer_type); 3699 3700 /* Compute the mask to access the bitfield. */ 3701 unsigned_type = lang_hooks.types.type_for_size (*pbitsize, 1); 3702 precision = TYPE_PRECISION (unsigned_type); 3703 3704 mask = build_int_cst (unsigned_type, -1); 3705 mask = force_fit_type (mask, 0, false, false); 3706 3707 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0); 3708 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0); 3709 3710 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */ 3711 if (and_mask != 0) 3712 mask = fold_build2 (BIT_AND_EXPR, unsigned_type, 3713 fold_convert (unsigned_type, and_mask), mask); 3714 3715 *pmask = mask; 3716 *pand_mask = and_mask; 3717 return inner; 3718} 3719 3720/* Return nonzero if MASK represents a mask of SIZE ones in the low-order 3721 bit positions. */ 3722 3723static int 3724all_ones_mask_p (tree mask, int size) 3725{ 3726 tree type = TREE_TYPE (mask); 3727 unsigned int precision = TYPE_PRECISION (type); 3728 tree tmask; 3729 3730 tmask = build_int_cst (lang_hooks.types.signed_type (type), -1); 3731 tmask = force_fit_type (tmask, 0, false, false); 3732 3733 return 3734 tree_int_cst_equal (mask, 3735 const_binop (RSHIFT_EXPR, 3736 const_binop (LSHIFT_EXPR, tmask, 3737 size_int (precision - size), 3738 0), 3739 size_int (precision - size), 0)); 3740} 3741 3742/* Subroutine for fold: determine if VAL is the INTEGER_CONST that 3743 represents the sign bit of EXP's type. If EXP represents a sign 3744 or zero extension, also test VAL against the unextended type. 3745 The return value is the (sub)expression whose sign bit is VAL, 3746 or NULL_TREE otherwise. */ 3747 3748static tree 3749sign_bit_p (tree exp, tree val) 3750{ 3751 unsigned HOST_WIDE_INT mask_lo, lo; 3752 HOST_WIDE_INT mask_hi, hi; 3753 int width; 3754 tree t; 3755 3756 /* Tree EXP must have an integral type. */ 3757 t = TREE_TYPE (exp); 3758 if (! INTEGRAL_TYPE_P (t)) 3759 return NULL_TREE; 3760 3761 /* Tree VAL must be an integer constant. */ 3762 if (TREE_CODE (val) != INTEGER_CST 3763 || TREE_CONSTANT_OVERFLOW (val)) 3764 return NULL_TREE; 3765 3766 width = TYPE_PRECISION (t); 3767 if (width > HOST_BITS_PER_WIDE_INT) 3768 { 3769 hi = (unsigned HOST_WIDE_INT) 1 << (width - HOST_BITS_PER_WIDE_INT - 1); 3770 lo = 0; 3771 3772 mask_hi = ((unsigned HOST_WIDE_INT) -1 3773 >> (2 * HOST_BITS_PER_WIDE_INT - width)); 3774 mask_lo = -1; 3775 } 3776 else 3777 { 3778 hi = 0; 3779 lo = (unsigned HOST_WIDE_INT) 1 << (width - 1); 3780 3781 mask_hi = 0; 3782 mask_lo = ((unsigned HOST_WIDE_INT) -1 3783 >> (HOST_BITS_PER_WIDE_INT - width)); 3784 } 3785 3786 /* We mask off those bits beyond TREE_TYPE (exp) so that we can 3787 treat VAL as if it were unsigned. */ 3788 if ((TREE_INT_CST_HIGH (val) & mask_hi) == hi 3789 && (TREE_INT_CST_LOW (val) & mask_lo) == lo) 3790 return exp; 3791 3792 /* Handle extension from a narrower type. */ 3793 if (TREE_CODE (exp) == NOP_EXPR 3794 && TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp, 0))) < width) 3795 return sign_bit_p (TREE_OPERAND (exp, 0), val); 3796 3797 return NULL_TREE; 3798} 3799 3800/* Subroutine for fold_truthop: determine if an operand is simple enough 3801 to be evaluated unconditionally. */ 3802 3803static int 3804simple_operand_p (tree exp) 3805{ 3806 /* Strip any conversions that don't change the machine mode. */ 3807 STRIP_NOPS (exp); 3808 3809 return (CONSTANT_CLASS_P (exp) 3810 || TREE_CODE (exp) == SSA_NAME 3811 || (DECL_P (exp) 3812 && ! TREE_ADDRESSABLE (exp) 3813 && ! TREE_THIS_VOLATILE (exp) 3814 && ! DECL_NONLOCAL (exp) 3815 /* Don't regard global variables as simple. They may be 3816 allocated in ways unknown to the compiler (shared memory, 3817 #pragma weak, etc). */ 3818 && ! TREE_PUBLIC (exp) 3819 && ! DECL_EXTERNAL (exp) 3820 /* Loading a static variable is unduly expensive, but global 3821 registers aren't expensive. */ 3822 && (! TREE_STATIC (exp) || DECL_REGISTER (exp)))); 3823} 3824 3825/* The following functions are subroutines to fold_range_test and allow it to 3826 try to change a logical combination of comparisons into a range test. 3827 3828 For example, both 3829 X == 2 || X == 3 || X == 4 || X == 5 3830 and 3831 X >= 2 && X <= 5 3832 are converted to 3833 (unsigned) (X - 2) <= 3 3834 3835 We describe each set of comparisons as being either inside or outside 3836 a range, using a variable named like IN_P, and then describe the 3837 range with a lower and upper bound. If one of the bounds is omitted, 3838 it represents either the highest or lowest value of the type. 3839 3840 In the comments below, we represent a range by two numbers in brackets 3841 preceded by a "+" to designate being inside that range, or a "-" to 3842 designate being outside that range, so the condition can be inverted by 3843 flipping the prefix. An omitted bound is represented by a "-". For 3844 example, "- [-, 10]" means being outside the range starting at the lowest 3845 possible value and ending at 10, in other words, being greater than 10. 3846 The range "+ [-, -]" is always true and hence the range "- [-, -]" is 3847 always false. 3848 3849 We set up things so that the missing bounds are handled in a consistent 3850 manner so neither a missing bound nor "true" and "false" need to be 3851 handled using a special case. */ 3852 3853/* Return the result of applying CODE to ARG0 and ARG1, but handle the case 3854 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P 3855 and UPPER1_P are nonzero if the respective argument is an upper bound 3856 and zero for a lower. TYPE, if nonzero, is the type of the result; it 3857 must be specified for a comparison. ARG1 will be converted to ARG0's 3858 type if both are specified. */ 3859 3860static tree 3861range_binop (enum tree_code code, tree type, tree arg0, int upper0_p, 3862 tree arg1, int upper1_p) 3863{ 3864 tree tem; 3865 int result; 3866 int sgn0, sgn1; 3867 3868 /* If neither arg represents infinity, do the normal operation. 3869 Else, if not a comparison, return infinity. Else handle the special 3870 comparison rules. Note that most of the cases below won't occur, but 3871 are handled for consistency. */ 3872 3873 if (arg0 != 0 && arg1 != 0) 3874 { 3875 tem = fold_build2 (code, type != 0 ? type : TREE_TYPE (arg0), 3876 arg0, fold_convert (TREE_TYPE (arg0), arg1)); 3877 STRIP_NOPS (tem); 3878 return TREE_CODE (tem) == INTEGER_CST ? tem : 0; 3879 } 3880 3881 if (TREE_CODE_CLASS (code) != tcc_comparison) 3882 return 0; 3883 3884 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0 3885 for neither. In real maths, we cannot assume open ended ranges are 3886 the same. But, this is computer arithmetic, where numbers are finite. 3887 We can therefore make the transformation of any unbounded range with 3888 the value Z, Z being greater than any representable number. This permits 3889 us to treat unbounded ranges as equal. */ 3890 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1); 3891 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1); 3892 switch (code) 3893 { 3894 case EQ_EXPR: 3895 result = sgn0 == sgn1; 3896 break; 3897 case NE_EXPR: 3898 result = sgn0 != sgn1; 3899 break; 3900 case LT_EXPR: 3901 result = sgn0 < sgn1; 3902 break; 3903 case LE_EXPR: 3904 result = sgn0 <= sgn1; 3905 break; 3906 case GT_EXPR: 3907 result = sgn0 > sgn1; 3908 break; 3909 case GE_EXPR: 3910 result = sgn0 >= sgn1; 3911 break; 3912 default: 3913 gcc_unreachable (); 3914 } 3915 3916 return constant_boolean_node (result, type); 3917} 3918 3919/* Given EXP, a logical expression, set the range it is testing into 3920 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression 3921 actually being tested. *PLOW and *PHIGH will be made of the same 3922 type as the returned expression. If EXP is not a comparison, we 3923 will most likely not be returning a useful value and range. Set 3924 *STRICT_OVERFLOW_P to true if the return value is only valid 3925 because signed overflow is undefined; otherwise, do not change 3926 *STRICT_OVERFLOW_P. */ 3927 3928static tree 3929make_range (tree exp, int *pin_p, tree *plow, tree *phigh, 3930 bool *strict_overflow_p) 3931{ 3932 enum tree_code code; 3933 tree arg0 = NULL_TREE, arg1 = NULL_TREE; 3934 tree exp_type = NULL_TREE, arg0_type = NULL_TREE; 3935 int in_p, n_in_p; 3936 tree low, high, n_low, n_high; 3937 3938 /* Start with simply saying "EXP != 0" and then look at the code of EXP 3939 and see if we can refine the range. Some of the cases below may not 3940 happen, but it doesn't seem worth worrying about this. We "continue" 3941 the outer loop when we've changed something; otherwise we "break" 3942 the switch, which will "break" the while. */ 3943 3944 in_p = 0; 3945 low = high = build_int_cst (TREE_TYPE (exp), 0); 3946 3947 while (1) 3948 { 3949 code = TREE_CODE (exp); 3950 exp_type = TREE_TYPE (exp); 3951 3952 if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code))) 3953 { 3954 if (TREE_CODE_LENGTH (code) > 0) 3955 arg0 = TREE_OPERAND (exp, 0); 3956 if (TREE_CODE_CLASS (code) == tcc_comparison 3957 || TREE_CODE_CLASS (code) == tcc_unary 3958 || TREE_CODE_CLASS (code) == tcc_binary) 3959 arg0_type = TREE_TYPE (arg0); 3960 if (TREE_CODE_CLASS (code) == tcc_binary 3961 || TREE_CODE_CLASS (code) == tcc_comparison 3962 || (TREE_CODE_CLASS (code) == tcc_expression 3963 && TREE_CODE_LENGTH (code) > 1)) 3964 arg1 = TREE_OPERAND (exp, 1); 3965 } 3966 3967 switch (code) 3968 { 3969 case TRUTH_NOT_EXPR: 3970 in_p = ! in_p, exp = arg0; 3971 continue; 3972 3973 case EQ_EXPR: case NE_EXPR: 3974 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR: 3975 /* We can only do something if the range is testing for zero 3976 and if the second operand is an integer constant. Note that 3977 saying something is "in" the range we make is done by 3978 complementing IN_P since it will set in the initial case of 3979 being not equal to zero; "out" is leaving it alone. */ 3980 if (low == 0 || high == 0 3981 || ! integer_zerop (low) || ! integer_zerop (high) 3982 || TREE_CODE (arg1) != INTEGER_CST) 3983 break; 3984 3985 switch (code) 3986 { 3987 case NE_EXPR: /* - [c, c] */ 3988 low = high = arg1; 3989 break; 3990 case EQ_EXPR: /* + [c, c] */ 3991 in_p = ! in_p, low = high = arg1; 3992 break; 3993 case GT_EXPR: /* - [-, c] */ 3994 low = 0, high = arg1; 3995 break; 3996 case GE_EXPR: /* + [c, -] */ 3997 in_p = ! in_p, low = arg1, high = 0; 3998 break; 3999 case LT_EXPR: /* - [c, -] */ 4000 low = arg1, high = 0; 4001 break; 4002 case LE_EXPR: /* + [-, c] */ 4003 in_p = ! in_p, low = 0, high = arg1; 4004 break; 4005 default: 4006 gcc_unreachable (); 4007 } 4008 4009 /* If this is an unsigned comparison, we also know that EXP is 4010 greater than or equal to zero. We base the range tests we make 4011 on that fact, so we record it here so we can parse existing 4012 range tests. We test arg0_type since often the return type 4013 of, e.g. EQ_EXPR, is boolean. */ 4014 if (TYPE_UNSIGNED (arg0_type) && (low == 0 || high == 0)) 4015 { 4016 if (! merge_ranges (&n_in_p, &n_low, &n_high, 4017 in_p, low, high, 1, 4018 build_int_cst (arg0_type, 0), 4019 NULL_TREE)) 4020 break; 4021 4022 in_p = n_in_p, low = n_low, high = n_high; 4023 4024 /* If the high bound is missing, but we have a nonzero low 4025 bound, reverse the range so it goes from zero to the low bound 4026 minus 1. */ 4027 if (high == 0 && low && ! integer_zerop (low)) 4028 { 4029 in_p = ! in_p; 4030 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0, 4031 integer_one_node, 0); 4032 low = build_int_cst (arg0_type, 0); 4033 } 4034 } 4035 4036 exp = arg0; 4037 continue; 4038 4039 case NEGATE_EXPR: 4040 /* (-x) IN [a,b] -> x in [-b, -a] */ 4041 n_low = range_binop (MINUS_EXPR, exp_type, 4042 build_int_cst (exp_type, 0), 4043 0, high, 1); 4044 n_high = range_binop (MINUS_EXPR, exp_type, 4045 build_int_cst (exp_type, 0), 4046 0, low, 0); 4047 low = n_low, high = n_high; 4048 exp = arg0; 4049 continue; 4050 4051 case BIT_NOT_EXPR: 4052 /* ~ X -> -X - 1 */ 4053 exp = build2 (MINUS_EXPR, exp_type, negate_expr (arg0), 4054 build_int_cst (exp_type, 1)); 4055 continue; 4056 4057 case PLUS_EXPR: case MINUS_EXPR: 4058 if (TREE_CODE (arg1) != INTEGER_CST) 4059 break; 4060 4061 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot 4062 move a constant to the other side. */ 4063 if (!TYPE_UNSIGNED (arg0_type) 4064 && !TYPE_OVERFLOW_UNDEFINED (arg0_type)) 4065 break; 4066 4067 /* If EXP is signed, any overflow in the computation is undefined, 4068 so we don't worry about it so long as our computations on 4069 the bounds don't overflow. For unsigned, overflow is defined 4070 and this is exactly the right thing. */ 4071 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR, 4072 arg0_type, low, 0, arg1, 0); 4073 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR, 4074 arg0_type, high, 1, arg1, 0); 4075 if ((n_low != 0 && TREE_OVERFLOW (n_low)) 4076 || (n_high != 0 && TREE_OVERFLOW (n_high))) 4077 break; 4078 4079 if (TYPE_OVERFLOW_UNDEFINED (arg0_type)) 4080 *strict_overflow_p = true; 4081 4082 /* Check for an unsigned range which has wrapped around the maximum 4083 value thus making n_high < n_low, and normalize it. */ 4084 if (n_low && n_high && tree_int_cst_lt (n_high, n_low)) 4085 { 4086 low = range_binop (PLUS_EXPR, arg0_type, n_high, 0, 4087 integer_one_node, 0); 4088 high = range_binop (MINUS_EXPR, arg0_type, n_low, 0, 4089 integer_one_node, 0); 4090 4091 /* If the range is of the form +/- [ x+1, x ], we won't 4092 be able to normalize it. But then, it represents the 4093 whole range or the empty set, so make it 4094 +/- [ -, - ]. */ 4095 if (tree_int_cst_equal (n_low, low) 4096 && tree_int_cst_equal (n_high, high)) 4097 low = high = 0; 4098 else 4099 in_p = ! in_p; 4100 } 4101 else 4102 low = n_low, high = n_high; 4103 4104 exp = arg0; 4105 continue; 4106 4107 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR: 4108 if (TYPE_PRECISION (arg0_type) > TYPE_PRECISION (exp_type)) 4109 break; 4110 4111 if (! INTEGRAL_TYPE_P (arg0_type) 4112 || (low != 0 && ! int_fits_type_p (low, arg0_type)) 4113 || (high != 0 && ! int_fits_type_p (high, arg0_type))) 4114 break; 4115 4116 n_low = low, n_high = high; 4117 4118 if (n_low != 0) 4119 n_low = fold_convert (arg0_type, n_low); 4120 4121 if (n_high != 0) 4122 n_high = fold_convert (arg0_type, n_high); 4123 4124 4125 /* If we're converting arg0 from an unsigned type, to exp, 4126 a signed type, we will be doing the comparison as unsigned. 4127 The tests above have already verified that LOW and HIGH 4128 are both positive. 4129 4130 So we have to ensure that we will handle large unsigned 4131 values the same way that the current signed bounds treat 4132 negative values. */ 4133 4134 if (!TYPE_UNSIGNED (exp_type) && TYPE_UNSIGNED (arg0_type)) 4135 { 4136 tree high_positive; 4137 tree equiv_type = lang_hooks.types.type_for_mode 4138 (TYPE_MODE (arg0_type), 1); 4139 4140 /* A range without an upper bound is, naturally, unbounded. 4141 Since convert would have cropped a very large value, use 4142 the max value for the destination type. */ 4143 high_positive 4144 = TYPE_MAX_VALUE (equiv_type) ? TYPE_MAX_VALUE (equiv_type) 4145 : TYPE_MAX_VALUE (arg0_type); 4146 4147 if (TYPE_PRECISION (exp_type) == TYPE_PRECISION (arg0_type)) 4148 high_positive = fold_build2 (RSHIFT_EXPR, arg0_type, 4149 fold_convert (arg0_type, 4150 high_positive), 4151 fold_convert (arg0_type, 4152 integer_one_node)); 4153 4154 /* If the low bound is specified, "and" the range with the 4155 range for which the original unsigned value will be 4156 positive. */ 4157 if (low != 0) 4158 { 4159 if (! merge_ranges (&n_in_p, &n_low, &n_high, 4160 1, n_low, n_high, 1, 4161 fold_convert (arg0_type, 4162 integer_zero_node), 4163 high_positive)) 4164 break; 4165 4166 in_p = (n_in_p == in_p); 4167 } 4168 else 4169 { 4170 /* Otherwise, "or" the range with the range of the input 4171 that will be interpreted as negative. */ 4172 if (! merge_ranges (&n_in_p, &n_low, &n_high, 4173 0, n_low, n_high, 1, 4174 fold_convert (arg0_type, 4175 integer_zero_node), 4176 high_positive)) 4177 break; 4178 4179 in_p = (in_p != n_in_p); 4180 } 4181 } 4182 4183 exp = arg0; 4184 low = n_low, high = n_high; 4185 continue; 4186 4187 default: 4188 break; 4189 } 4190 4191 break; 4192 } 4193 4194 /* If EXP is a constant, we can evaluate whether this is true or false. */ 4195 if (TREE_CODE (exp) == INTEGER_CST) 4196 { 4197 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node, 4198 exp, 0, low, 0)) 4199 && integer_onep (range_binop (LE_EXPR, integer_type_node, 4200 exp, 1, high, 1))); 4201 low = high = 0; 4202 exp = 0; 4203 } 4204 4205 *pin_p = in_p, *plow = low, *phigh = high; 4206 return exp; 4207} 4208 4209/* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result 4210 type, TYPE, return an expression to test if EXP is in (or out of, depending 4211 on IN_P) the range. Return 0 if the test couldn't be created. */ 4212 4213static tree 4214build_range_check (tree type, tree exp, int in_p, tree low, tree high) 4215{ 4216 tree etype = TREE_TYPE (exp); 4217 tree value; 4218 4219#ifdef HAVE_canonicalize_funcptr_for_compare 4220 /* Disable this optimization for function pointer expressions 4221 on targets that require function pointer canonicalization. */ 4222 if (HAVE_canonicalize_funcptr_for_compare 4223 && TREE_CODE (etype) == POINTER_TYPE 4224 && TREE_CODE (TREE_TYPE (etype)) == FUNCTION_TYPE) 4225 return NULL_TREE; 4226#endif 4227 4228 if (! in_p) 4229 { 4230 value = build_range_check (type, exp, 1, low, high); 4231 if (value != 0) 4232 return invert_truthvalue (value); 4233 4234 return 0; 4235 } 4236 4237 if (low == 0 && high == 0) 4238 return build_int_cst (type, 1); 4239 4240 if (low == 0) 4241 return fold_build2 (LE_EXPR, type, exp, 4242 fold_convert (etype, high)); 4243 4244 if (high == 0) 4245 return fold_build2 (GE_EXPR, type, exp, 4246 fold_convert (etype, low)); 4247 4248 if (operand_equal_p (low, high, 0)) 4249 return fold_build2 (EQ_EXPR, type, exp, 4250 fold_convert (etype, low)); 4251 4252 if (integer_zerop (low)) 4253 { 4254 if (! TYPE_UNSIGNED (etype)) 4255 { 4256 etype = lang_hooks.types.unsigned_type (etype); 4257 high = fold_convert (etype, high); 4258 exp = fold_convert (etype, exp); 4259 } 4260 return build_range_check (type, exp, 1, 0, high); 4261 } 4262 4263 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */ 4264 if (integer_onep (low) && TREE_CODE (high) == INTEGER_CST) 4265 { 4266 unsigned HOST_WIDE_INT lo; 4267 HOST_WIDE_INT hi; 4268 int prec; 4269 4270 prec = TYPE_PRECISION (etype); 4271 if (prec <= HOST_BITS_PER_WIDE_INT) 4272 { 4273 hi = 0; 4274 lo = ((unsigned HOST_WIDE_INT) 1 << (prec - 1)) - 1; 4275 } 4276 else 4277 { 4278 hi = ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)) - 1; 4279 lo = (unsigned HOST_WIDE_INT) -1; 4280 } 4281 4282 if (TREE_INT_CST_HIGH (high) == hi && TREE_INT_CST_LOW (high) == lo) 4283 { 4284 if (TYPE_UNSIGNED (etype)) 4285 { 4286 etype = lang_hooks.types.signed_type (etype); 4287 exp = fold_convert (etype, exp); 4288 } 4289 return fold_build2 (GT_EXPR, type, exp, 4290 build_int_cst (etype, 0)); 4291 } 4292 } 4293 4294 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low). 4295 This requires wrap-around arithmetics for the type of the expression. */ 4296 switch (TREE_CODE (etype)) 4297 { 4298 case INTEGER_TYPE: 4299 /* There is no requirement that LOW be within the range of ETYPE 4300 if the latter is a subtype. It must, however, be within the base 4301 type of ETYPE. So be sure we do the subtraction in that type. */ 4302 if (TREE_TYPE (etype)) 4303 etype = TREE_TYPE (etype); 4304 break; 4305 4306 case ENUMERAL_TYPE: 4307 case BOOLEAN_TYPE: 4308 etype = lang_hooks.types.type_for_size (TYPE_PRECISION (etype), 4309 TYPE_UNSIGNED (etype)); 4310 break; 4311 4312 default: 4313 break; 4314 } 4315 4316 /* If we don't have wrap-around arithmetics upfront, try to force it. */ 4317 if (TREE_CODE (etype) == INTEGER_TYPE 4318 && !TYPE_OVERFLOW_WRAPS (etype)) 4319 { 4320 tree utype, minv, maxv; 4321 4322 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN 4323 for the type in question, as we rely on this here. */ 4324 utype = lang_hooks.types.unsigned_type (etype); 4325 maxv = fold_convert (utype, TYPE_MAX_VALUE (etype)); 4326 maxv = range_binop (PLUS_EXPR, NULL_TREE, maxv, 1, 4327 integer_one_node, 1); 4328 minv = fold_convert (utype, TYPE_MIN_VALUE (etype)); 4329 4330 if (integer_zerop (range_binop (NE_EXPR, integer_type_node, 4331 minv, 1, maxv, 1))) 4332 etype = utype; 4333 else 4334 return 0; 4335 } 4336 4337 high = fold_convert (etype, high); 4338 low = fold_convert (etype, low); 4339 exp = fold_convert (etype, exp); 4340 4341 value = const_binop (MINUS_EXPR, high, low, 0); 4342 4343 if (value != 0 && !TREE_OVERFLOW (value)) 4344 return build_range_check (type, 4345 fold_build2 (MINUS_EXPR, etype, exp, low), 4346 1, build_int_cst (etype, 0), value); 4347 4348 return 0; 4349} 4350 4351/* Return the predecessor of VAL in its type, handling the infinite case. */ 4352 4353static tree 4354range_predecessor (tree val) 4355{ 4356 tree type = TREE_TYPE (val); 4357 4358 if (INTEGRAL_TYPE_P (type) 4359 && operand_equal_p (val, TYPE_MIN_VALUE (type), 0)) 4360 return 0; 4361 else 4362 return range_binop (MINUS_EXPR, NULL_TREE, val, 0, integer_one_node, 0); 4363} 4364 4365/* Return the successor of VAL in its type, handling the infinite case. */ 4366 4367static tree 4368range_successor (tree val) 4369{ 4370 tree type = TREE_TYPE (val); 4371 4372 if (INTEGRAL_TYPE_P (type) 4373 && operand_equal_p (val, TYPE_MAX_VALUE (type), 0)) 4374 return 0; 4375 else 4376 return range_binop (PLUS_EXPR, NULL_TREE, val, 0, integer_one_node, 0); 4377} 4378 4379/* Given two ranges, see if we can merge them into one. Return 1 if we 4380 can, 0 if we can't. Set the output range into the specified parameters. */ 4381 4382static int 4383merge_ranges (int *pin_p, tree *plow, tree *phigh, int in0_p, tree low0, 4384 tree high0, int in1_p, tree low1, tree high1) 4385{ 4386 int no_overlap; 4387 int subset; 4388 int temp; 4389 tree tem; 4390 int in_p; 4391 tree low, high; 4392 int lowequal = ((low0 == 0 && low1 == 0) 4393 || integer_onep (range_binop (EQ_EXPR, integer_type_node, 4394 low0, 0, low1, 0))); 4395 int highequal = ((high0 == 0 && high1 == 0) 4396 || integer_onep (range_binop (EQ_EXPR, integer_type_node, 4397 high0, 1, high1, 1))); 4398 4399 /* Make range 0 be the range that starts first, or ends last if they 4400 start at the same value. Swap them if it isn't. */ 4401 if (integer_onep (range_binop (GT_EXPR, integer_type_node, 4402 low0, 0, low1, 0)) 4403 || (lowequal 4404 && integer_onep (range_binop (GT_EXPR, integer_type_node, 4405 high1, 1, high0, 1)))) 4406 { 4407 temp = in0_p, in0_p = in1_p, in1_p = temp; 4408 tem = low0, low0 = low1, low1 = tem; 4409 tem = high0, high0 = high1, high1 = tem; 4410 } 4411 4412 /* Now flag two cases, whether the ranges are disjoint or whether the 4413 second range is totally subsumed in the first. Note that the tests 4414 below are simplified by the ones above. */ 4415 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node, 4416 high0, 1, low1, 0)); 4417 subset = integer_onep (range_binop (LE_EXPR, integer_type_node, 4418 high1, 1, high0, 1)); 4419 4420 /* We now have four cases, depending on whether we are including or 4421 excluding the two ranges. */ 4422 if (in0_p && in1_p) 4423 { 4424 /* If they don't overlap, the result is false. If the second range 4425 is a subset it is the result. Otherwise, the range is from the start 4426 of the second to the end of the first. */ 4427 if (no_overlap) 4428 in_p = 0, low = high = 0; 4429 else if (subset) 4430 in_p = 1, low = low1, high = high1; 4431 else 4432 in_p = 1, low = low1, high = high0; 4433 } 4434 4435 else if (in0_p && ! in1_p) 4436 { 4437 /* If they don't overlap, the result is the first range. If they are 4438 equal, the result is false. If the second range is a subset of the 4439 first, and the ranges begin at the same place, we go from just after 4440 the end of the second range to the end of the first. If the second 4441 range is not a subset of the first, or if it is a subset and both 4442 ranges end at the same place, the range starts at the start of the 4443 first range and ends just before the second range. 4444 Otherwise, we can't describe this as a single range. */ 4445 if (no_overlap) 4446 in_p = 1, low = low0, high = high0; 4447 else if (lowequal && highequal) 4448 in_p = 0, low = high = 0; 4449 else if (subset && lowequal) 4450 { 4451 low = range_successor (high1); 4452 high = high0; 4453 in_p = 1; 4454 if (low == 0) 4455 { 4456 /* We are in the weird situation where high0 > high1 but 4457 high1 has no successor. Punt. */ 4458 return 0; 4459 } 4460 } 4461 else if (! subset || highequal) 4462 { 4463 low = low0; 4464 high = range_predecessor (low1); 4465 in_p = 1; 4466 if (high == 0) 4467 { 4468 /* low0 < low1 but low1 has no predecessor. Punt. */ 4469 return 0; 4470 } 4471 } 4472 else 4473 return 0; 4474 } 4475 4476 else if (! in0_p && in1_p) 4477 { 4478 /* If they don't overlap, the result is the second range. If the second 4479 is a subset of the first, the result is false. Otherwise, 4480 the range starts just after the first range and ends at the 4481 end of the second. */ 4482 if (no_overlap) 4483 in_p = 1, low = low1, high = high1; 4484 else if (subset || highequal) 4485 in_p = 0, low = high = 0; 4486 else 4487 { 4488 low = range_successor (high0); 4489 high = high1; 4490 in_p = 1; 4491 if (low == 0) 4492 { 4493 /* high1 > high0 but high0 has no successor. Punt. */ 4494 return 0; 4495 } 4496 } 4497 } 4498 4499 else 4500 { 4501 /* The case where we are excluding both ranges. Here the complex case 4502 is if they don't overlap. In that case, the only time we have a 4503 range is if they are adjacent. If the second is a subset of the 4504 first, the result is the first. Otherwise, the range to exclude 4505 starts at the beginning of the first range and ends at the end of the 4506 second. */ 4507 if (no_overlap) 4508 { 4509 if (integer_onep (range_binop (EQ_EXPR, integer_type_node, 4510 range_successor (high0), 4511 1, low1, 0))) 4512 in_p = 0, low = low0, high = high1; 4513 else 4514 { 4515 /* Canonicalize - [min, x] into - [-, x]. */ 4516 if (low0 && TREE_CODE (low0) == INTEGER_CST) 4517 switch (TREE_CODE (TREE_TYPE (low0))) 4518 { 4519 case ENUMERAL_TYPE: 4520 if (TYPE_PRECISION (TREE_TYPE (low0)) 4521 != GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (low0)))) 4522 break; 4523 /* FALLTHROUGH */ 4524 case INTEGER_TYPE: 4525 if (tree_int_cst_equal (low0, 4526 TYPE_MIN_VALUE (TREE_TYPE (low0)))) 4527 low0 = 0; 4528 break; 4529 case POINTER_TYPE: 4530 if (TYPE_UNSIGNED (TREE_TYPE (low0)) 4531 && integer_zerop (low0)) 4532 low0 = 0; 4533 break; 4534 default: 4535 break; 4536 } 4537 4538 /* Canonicalize - [x, max] into - [x, -]. */ 4539 if (high1 && TREE_CODE (high1) == INTEGER_CST) 4540 switch (TREE_CODE (TREE_TYPE (high1))) 4541 { 4542 case ENUMERAL_TYPE: 4543 if (TYPE_PRECISION (TREE_TYPE (high1)) 4544 != GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (high1)))) 4545 break; 4546 /* FALLTHROUGH */ 4547 case INTEGER_TYPE: 4548 if (tree_int_cst_equal (high1, 4549 TYPE_MAX_VALUE (TREE_TYPE (high1)))) 4550 high1 = 0; 4551 break; 4552 case POINTER_TYPE: 4553 if (TYPE_UNSIGNED (TREE_TYPE (high1)) 4554 && integer_zerop (range_binop (PLUS_EXPR, NULL_TREE, 4555 high1, 1, 4556 integer_one_node, 1))) 4557 high1 = 0; 4558 break; 4559 default: 4560 break; 4561 } 4562 4563 /* The ranges might be also adjacent between the maximum and 4564 minimum values of the given type. For 4565 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y 4566 return + [x + 1, y - 1]. */ 4567 if (low0 == 0 && high1 == 0) 4568 { 4569 low = range_successor (high0); 4570 high = range_predecessor (low1); 4571 if (low == 0 || high == 0) 4572 return 0; 4573 4574 in_p = 1; 4575 } 4576 else 4577 return 0; 4578 } 4579 } 4580 else if (subset) 4581 in_p = 0, low = low0, high = high0; 4582 else 4583 in_p = 0, low = low0, high = high1; 4584 } 4585 4586 *pin_p = in_p, *plow = low, *phigh = high; 4587 return 1; 4588} 4589 4590 4591/* Subroutine of fold, looking inside expressions of the form 4592 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands 4593 of the COND_EXPR. This function is being used also to optimize 4594 A op B ? C : A, by reversing the comparison first. 4595 4596 Return a folded expression whose code is not a COND_EXPR 4597 anymore, or NULL_TREE if no folding opportunity is found. */ 4598 4599static tree 4600fold_cond_expr_with_comparison (tree type, tree arg0, tree arg1, tree arg2) 4601{ 4602 enum tree_code comp_code = TREE_CODE (arg0); 4603 tree arg00 = TREE_OPERAND (arg0, 0); 4604 tree arg01 = TREE_OPERAND (arg0, 1); 4605 tree arg1_type = TREE_TYPE (arg1); 4606 tree tem; 4607 4608 STRIP_NOPS (arg1); 4609 STRIP_NOPS (arg2); 4610 4611 /* If we have A op 0 ? A : -A, consider applying the following 4612 transformations: 4613 4614 A == 0? A : -A same as -A 4615 A != 0? A : -A same as A 4616 A >= 0? A : -A same as abs (A) 4617 A > 0? A : -A same as abs (A) 4618 A <= 0? A : -A same as -abs (A) 4619 A < 0? A : -A same as -abs (A) 4620 4621 None of these transformations work for modes with signed 4622 zeros. If A is +/-0, the first two transformations will 4623 change the sign of the result (from +0 to -0, or vice 4624 versa). The last four will fix the sign of the result, 4625 even though the original expressions could be positive or 4626 negative, depending on the sign of A. 4627 4628 Note that all these transformations are correct if A is 4629 NaN, since the two alternatives (A and -A) are also NaNs. */ 4630 if ((FLOAT_TYPE_P (TREE_TYPE (arg01)) 4631 ? real_zerop (arg01) 4632 : integer_zerop (arg01)) 4633 && ((TREE_CODE (arg2) == NEGATE_EXPR 4634 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0)) 4635 /* In the case that A is of the form X-Y, '-A' (arg2) may 4636 have already been folded to Y-X, check for that. */ 4637 || (TREE_CODE (arg1) == MINUS_EXPR 4638 && TREE_CODE (arg2) == MINUS_EXPR 4639 && operand_equal_p (TREE_OPERAND (arg1, 0), 4640 TREE_OPERAND (arg2, 1), 0) 4641 && operand_equal_p (TREE_OPERAND (arg1, 1), 4642 TREE_OPERAND (arg2, 0), 0)))) 4643 switch (comp_code) 4644 { 4645 case EQ_EXPR: 4646 case UNEQ_EXPR: 4647 tem = fold_convert (arg1_type, arg1); 4648 return pedantic_non_lvalue (fold_convert (type, negate_expr (tem))); 4649 case NE_EXPR: 4650 case LTGT_EXPR: 4651 return pedantic_non_lvalue (fold_convert (type, arg1)); 4652 case UNGE_EXPR: 4653 case UNGT_EXPR: 4654 if (flag_trapping_math) 4655 break; 4656 /* Fall through. */ 4657 case GE_EXPR: 4658 case GT_EXPR: 4659 if (TYPE_UNSIGNED (TREE_TYPE (arg1))) 4660 arg1 = fold_convert (lang_hooks.types.signed_type 4661 (TREE_TYPE (arg1)), arg1); 4662 tem = fold_build1 (ABS_EXPR, TREE_TYPE (arg1), arg1); 4663 return pedantic_non_lvalue (fold_convert (type, tem)); 4664 case UNLE_EXPR: 4665 case UNLT_EXPR: 4666 if (flag_trapping_math) 4667 break; 4668 case LE_EXPR: 4669 case LT_EXPR: 4670 if (TYPE_UNSIGNED (TREE_TYPE (arg1))) 4671 arg1 = fold_convert (lang_hooks.types.signed_type 4672 (TREE_TYPE (arg1)), arg1); 4673 tem = fold_build1 (ABS_EXPR, TREE_TYPE (arg1), arg1); 4674 return negate_expr (fold_convert (type, tem)); 4675 default: 4676 gcc_assert (TREE_CODE_CLASS (comp_code) == tcc_comparison); 4677 break; 4678 } 4679 4680 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise 4681 A == 0 ? A : 0 is always 0 unless A is -0. Note that 4682 both transformations are correct when A is NaN: A != 0 4683 is then true, and A == 0 is false. */ 4684 4685 if (integer_zerop (arg01) && integer_zerop (arg2)) 4686 { 4687 if (comp_code == NE_EXPR) 4688 return pedantic_non_lvalue (fold_convert (type, arg1)); 4689 else if (comp_code == EQ_EXPR) 4690 return build_int_cst (type, 0); 4691 } 4692 4693 /* Try some transformations of A op B ? A : B. 4694 4695 A == B? A : B same as B 4696 A != B? A : B same as A 4697 A >= B? A : B same as max (A, B) 4698 A > B? A : B same as max (B, A) 4699 A <= B? A : B same as min (A, B) 4700 A < B? A : B same as min (B, A) 4701 4702 As above, these transformations don't work in the presence 4703 of signed zeros. For example, if A and B are zeros of 4704 opposite sign, the first two transformations will change 4705 the sign of the result. In the last four, the original 4706 expressions give different results for (A=+0, B=-0) and 4707 (A=-0, B=+0), but the transformed expressions do not. 4708 4709 The first two transformations are correct if either A or B 4710 is a NaN. In the first transformation, the condition will 4711 be false, and B will indeed be chosen. In the case of the 4712 second transformation, the condition A != B will be true, 4713 and A will be chosen. 4714 4715 The conversions to max() and min() are not correct if B is 4716 a number and A is not. The conditions in the original 4717 expressions will be false, so all four give B. The min() 4718 and max() versions would give a NaN instead. */ 4719 if (operand_equal_for_comparison_p (arg01, arg2, arg00) 4720 /* Avoid these transformations if the COND_EXPR may be used 4721 as an lvalue in the C++ front-end. PR c++/19199. */ 4722 && (in_gimple_form 4723 || (strcmp (lang_hooks.name, "GNU C++") != 0 4724 && strcmp (lang_hooks.name, "GNU Objective-C++") != 0) 4725 || ! maybe_lvalue_p (arg1) 4726 || ! maybe_lvalue_p (arg2))) 4727 { 4728 tree comp_op0 = arg00; 4729 tree comp_op1 = arg01; 4730 tree comp_type = TREE_TYPE (comp_op0); 4731 4732 /* Avoid adding NOP_EXPRs in case this is an lvalue. */ 4733 if (TYPE_MAIN_VARIANT (comp_type) == TYPE_MAIN_VARIANT (type)) 4734 { 4735 comp_type = type; 4736 comp_op0 = arg1; 4737 comp_op1 = arg2; 4738 } 4739 4740 switch (comp_code) 4741 { 4742 case EQ_EXPR: 4743 return pedantic_non_lvalue (fold_convert (type, arg2)); 4744 case NE_EXPR: 4745 return pedantic_non_lvalue (fold_convert (type, arg1)); 4746 case LE_EXPR: 4747 case LT_EXPR: 4748 case UNLE_EXPR: 4749 case UNLT_EXPR: 4750 /* In C++ a ?: expression can be an lvalue, so put the 4751 operand which will be used if they are equal first 4752 so that we can convert this back to the 4753 corresponding COND_EXPR. */ 4754 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1)))) 4755 { 4756 comp_op0 = fold_convert (comp_type, comp_op0); 4757 comp_op1 = fold_convert (comp_type, comp_op1); 4758 tem = (comp_code == LE_EXPR || comp_code == UNLE_EXPR) 4759 ? fold_build2 (MIN_EXPR, comp_type, comp_op0, comp_op1) 4760 : fold_build2 (MIN_EXPR, comp_type, comp_op1, comp_op0); 4761 return pedantic_non_lvalue (fold_convert (type, tem)); 4762 } 4763 break; 4764 case GE_EXPR: 4765 case GT_EXPR: 4766 case UNGE_EXPR: 4767 case UNGT_EXPR: 4768 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1)))) 4769 { 4770 comp_op0 = fold_convert (comp_type, comp_op0); 4771 comp_op1 = fold_convert (comp_type, comp_op1); 4772 tem = (comp_code == GE_EXPR || comp_code == UNGE_EXPR) 4773 ? fold_build2 (MAX_EXPR, comp_type, comp_op0, comp_op1) 4774 : fold_build2 (MAX_EXPR, comp_type, comp_op1, comp_op0); 4775 return pedantic_non_lvalue (fold_convert (type, tem)); 4776 } 4777 break; 4778 case UNEQ_EXPR: 4779 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1)))) 4780 return pedantic_non_lvalue (fold_convert (type, arg2)); 4781 break; 4782 case LTGT_EXPR: 4783 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1)))) 4784 return pedantic_non_lvalue (fold_convert (type, arg1)); 4785 break; 4786 default: 4787 gcc_assert (TREE_CODE_CLASS (comp_code) == tcc_comparison); 4788 break; 4789 } 4790 } 4791 4792 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers, 4793 we might still be able to simplify this. For example, 4794 if C1 is one less or one more than C2, this might have started 4795 out as a MIN or MAX and been transformed by this function. 4796 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */ 4797 4798 if (INTEGRAL_TYPE_P (type) 4799 && TREE_CODE (arg01) == INTEGER_CST 4800 && TREE_CODE (arg2) == INTEGER_CST) 4801 switch (comp_code) 4802 { 4803 case EQ_EXPR: 4804 /* We can replace A with C1 in this case. */ 4805 arg1 = fold_convert (type, arg01); 4806 return fold_build3 (COND_EXPR, type, arg0, arg1, arg2); 4807 4808 case LT_EXPR: 4809 /* If C1 is C2 + 1, this is min(A, C2). */ 4810 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 4811 OEP_ONLY_CONST) 4812 && operand_equal_p (arg01, 4813 const_binop (PLUS_EXPR, arg2, 4814 integer_one_node, 0), 4815 OEP_ONLY_CONST)) 4816 return pedantic_non_lvalue (fold_build2 (MIN_EXPR, 4817 type, arg1, arg2)); 4818 break; 4819 4820 case LE_EXPR: 4821 /* If C1 is C2 - 1, this is min(A, C2). */ 4822 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 4823 OEP_ONLY_CONST) 4824 && operand_equal_p (arg01, 4825 const_binop (MINUS_EXPR, arg2, 4826 integer_one_node, 0), 4827 OEP_ONLY_CONST)) 4828 return pedantic_non_lvalue (fold_build2 (MIN_EXPR, 4829 type, arg1, arg2)); 4830 break; 4831 4832 case GT_EXPR: 4833 /* If C1 is C2 - 1, this is max(A, C2). */ 4834 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 4835 OEP_ONLY_CONST) 4836 && operand_equal_p (arg01, 4837 const_binop (MINUS_EXPR, arg2, 4838 integer_one_node, 0), 4839 OEP_ONLY_CONST)) 4840 return pedantic_non_lvalue (fold_build2 (MAX_EXPR, 4841 type, arg1, arg2)); 4842 break; 4843 4844 case GE_EXPR: 4845 /* If C1 is C2 + 1, this is max(A, C2). */ 4846 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 4847 OEP_ONLY_CONST) 4848 && operand_equal_p (arg01, 4849 const_binop (PLUS_EXPR, arg2, 4850 integer_one_node, 0), 4851 OEP_ONLY_CONST)) 4852 return pedantic_non_lvalue (fold_build2 (MAX_EXPR, 4853 type, arg1, arg2)); 4854 break; 4855 case NE_EXPR: 4856 break; 4857 default: 4858 gcc_unreachable (); 4859 } 4860 4861 return NULL_TREE; 4862} 4863 4864 4865 4866#ifndef LOGICAL_OP_NON_SHORT_CIRCUIT 4867#define LOGICAL_OP_NON_SHORT_CIRCUIT (BRANCH_COST >= 2) 4868#endif 4869 4870/* EXP is some logical combination of boolean tests. See if we can 4871 merge it into some range test. Return the new tree if so. */ 4872 4873static tree 4874fold_range_test (enum tree_code code, tree type, tree op0, tree op1) 4875{ 4876 int or_op = (code == TRUTH_ORIF_EXPR 4877 || code == TRUTH_OR_EXPR); 4878 int in0_p, in1_p, in_p; 4879 tree low0, low1, low, high0, high1, high; 4880 bool strict_overflow_p = false; 4881 tree lhs = make_range (op0, &in0_p, &low0, &high0, &strict_overflow_p); 4882 tree rhs = make_range (op1, &in1_p, &low1, &high1, &strict_overflow_p); 4883 tree tem; 4884 const char * const warnmsg = G_("assuming signed overflow does not occur " 4885 "when simplifying range test"); 4886 4887 /* If this is an OR operation, invert both sides; we will invert 4888 again at the end. */ 4889 if (or_op) 4890 in0_p = ! in0_p, in1_p = ! in1_p; 4891 4892 /* If both expressions are the same, if we can merge the ranges, and we 4893 can build the range test, return it or it inverted. If one of the 4894 ranges is always true or always false, consider it to be the same 4895 expression as the other. */ 4896 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0)) 4897 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0, 4898 in1_p, low1, high1) 4899 && 0 != (tem = (build_range_check (type, 4900 lhs != 0 ? lhs 4901 : rhs != 0 ? rhs : integer_zero_node, 4902 in_p, low, high)))) 4903 { 4904 if (strict_overflow_p) 4905 fold_overflow_warning (warnmsg, WARN_STRICT_OVERFLOW_COMPARISON); 4906 return or_op ? invert_truthvalue (tem) : tem; 4907 } 4908 4909 /* On machines where the branch cost is expensive, if this is a 4910 short-circuited branch and the underlying object on both sides 4911 is the same, make a non-short-circuit operation. */ 4912 else if (LOGICAL_OP_NON_SHORT_CIRCUIT 4913 && lhs != 0 && rhs != 0 4914 && (code == TRUTH_ANDIF_EXPR 4915 || code == TRUTH_ORIF_EXPR) 4916 && operand_equal_p (lhs, rhs, 0)) 4917 { 4918 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR 4919 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in 4920 which cases we can't do this. */ 4921 if (simple_operand_p (lhs)) 4922 return build2 (code == TRUTH_ANDIF_EXPR 4923 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR, 4924 type, op0, op1); 4925 4926 else if (lang_hooks.decls.global_bindings_p () == 0 4927 && ! CONTAINS_PLACEHOLDER_P (lhs)) 4928 { 4929 tree common = save_expr (lhs); 4930 4931 if (0 != (lhs = build_range_check (type, common, 4932 or_op ? ! in0_p : in0_p, 4933 low0, high0)) 4934 && (0 != (rhs = build_range_check (type, common, 4935 or_op ? ! in1_p : in1_p, 4936 low1, high1)))) 4937 { 4938 if (strict_overflow_p) 4939 fold_overflow_warning (warnmsg, 4940 WARN_STRICT_OVERFLOW_COMPARISON); 4941 return build2 (code == TRUTH_ANDIF_EXPR 4942 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR, 4943 type, lhs, rhs); 4944 } 4945 } 4946 } 4947 4948 return 0; 4949} 4950 4951/* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P 4952 bit value. Arrange things so the extra bits will be set to zero if and 4953 only if C is signed-extended to its full width. If MASK is nonzero, 4954 it is an INTEGER_CST that should be AND'ed with the extra bits. */ 4955 4956static tree 4957unextend (tree c, int p, int unsignedp, tree mask) 4958{ 4959 tree type = TREE_TYPE (c); 4960 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type)); 4961 tree temp; 4962 4963 if (p == modesize || unsignedp) 4964 return c; 4965 4966 /* We work by getting just the sign bit into the low-order bit, then 4967 into the high-order bit, then sign-extend. We then XOR that value 4968 with C. */ 4969 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0); 4970 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0); 4971 4972 /* We must use a signed type in order to get an arithmetic right shift. 4973 However, we must also avoid introducing accidental overflows, so that 4974 a subsequent call to integer_zerop will work. Hence we must 4975 do the type conversion here. At this point, the constant is either 4976 zero or one, and the conversion to a signed type can never overflow. 4977 We could get an overflow if this conversion is done anywhere else. */ 4978 if (TYPE_UNSIGNED (type)) 4979 temp = fold_convert (lang_hooks.types.signed_type (type), temp); 4980 4981 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0); 4982 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0); 4983 if (mask != 0) 4984 temp = const_binop (BIT_AND_EXPR, temp, 4985 fold_convert (TREE_TYPE (c), mask), 0); 4986 /* If necessary, convert the type back to match the type of C. */ 4987 if (TYPE_UNSIGNED (type)) 4988 temp = fold_convert (type, temp); 4989 4990 return fold_convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0)); 4991} 4992 4993/* Find ways of folding logical expressions of LHS and RHS: 4994 Try to merge two comparisons to the same innermost item. 4995 Look for range tests like "ch >= '0' && ch <= '9'". 4996 Look for combinations of simple terms on machines with expensive branches 4997 and evaluate the RHS unconditionally. 4998 4999 For example, if we have p->a == 2 && p->b == 4 and we can make an 5000 object large enough to span both A and B, we can do this with a comparison 5001 against the object ANDed with the a mask. 5002 5003 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking 5004 operations to do this with one comparison. 5005 5006 We check for both normal comparisons and the BIT_AND_EXPRs made this by 5007 function and the one above. 5008 5009 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR, 5010 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR. 5011 5012 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its 5013 two operands. 5014 5015 We return the simplified tree or 0 if no optimization is possible. */ 5016 5017static tree 5018fold_truthop (enum tree_code code, tree truth_type, tree lhs, tree rhs) 5019{ 5020 /* If this is the "or" of two comparisons, we can do something if 5021 the comparisons are NE_EXPR. If this is the "and", we can do something 5022 if the comparisons are EQ_EXPR. I.e., 5023 (a->b == 2 && a->c == 4) can become (a->new == NEW). 5024 5025 WANTED_CODE is this operation code. For single bit fields, we can 5026 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong" 5027 comparison for one-bit fields. */ 5028 5029 enum tree_code wanted_code; 5030 enum tree_code lcode, rcode; 5031 tree ll_arg, lr_arg, rl_arg, rr_arg; 5032 tree ll_inner, lr_inner, rl_inner, rr_inner; 5033 HOST_WIDE_INT ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos; 5034 HOST_WIDE_INT rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos; 5035 HOST_WIDE_INT xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos; 5036 HOST_WIDE_INT lnbitsize, lnbitpos, rnbitsize, rnbitpos; 5037 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp; 5038 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode; 5039 enum machine_mode lnmode, rnmode; 5040 tree ll_mask, lr_mask, rl_mask, rr_mask; 5041 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask; 5042 tree l_const, r_const; 5043 tree lntype, rntype, result; 5044 int first_bit, end_bit; 5045 int volatilep; 5046 tree orig_lhs = lhs, orig_rhs = rhs; 5047 enum tree_code orig_code = code; 5048 5049 /* Start by getting the comparison codes. Fail if anything is volatile. 5050 If one operand is a BIT_AND_EXPR with the constant one, treat it as if 5051 it were surrounded with a NE_EXPR. */ 5052 5053 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs)) 5054 return 0; 5055 5056 lcode = TREE_CODE (lhs); 5057 rcode = TREE_CODE (rhs); 5058 5059 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1))) 5060 { 5061 lhs = build2 (NE_EXPR, truth_type, lhs, 5062 build_int_cst (TREE_TYPE (lhs), 0)); 5063 lcode = NE_EXPR; 5064 } 5065 5066 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1))) 5067 { 5068 rhs = build2 (NE_EXPR, truth_type, rhs, 5069 build_int_cst (TREE_TYPE (rhs), 0)); 5070 rcode = NE_EXPR; 5071 } 5072 5073 if (TREE_CODE_CLASS (lcode) != tcc_comparison 5074 || TREE_CODE_CLASS (rcode) != tcc_comparison) 5075 return 0; 5076 5077 ll_arg = TREE_OPERAND (lhs, 0); 5078 lr_arg = TREE_OPERAND (lhs, 1); 5079 rl_arg = TREE_OPERAND (rhs, 0); 5080 rr_arg = TREE_OPERAND (rhs, 1); 5081 5082 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */ 5083 if (simple_operand_p (ll_arg) 5084 && simple_operand_p (lr_arg)) 5085 { 5086 tree result; 5087 if (operand_equal_p (ll_arg, rl_arg, 0) 5088 && operand_equal_p (lr_arg, rr_arg, 0)) 5089 { 5090 result = combine_comparisons (code, lcode, rcode, 5091 truth_type, ll_arg, lr_arg); 5092 if (result) 5093 return result; 5094 } 5095 else if (operand_equal_p (ll_arg, rr_arg, 0) 5096 && operand_equal_p (lr_arg, rl_arg, 0)) 5097 { 5098 result = combine_comparisons (code, lcode, 5099 swap_tree_comparison (rcode), 5100 truth_type, ll_arg, lr_arg); 5101 if (result) 5102 return result; 5103 } 5104 } 5105 5106 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR) 5107 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR); 5108 5109 /* If the RHS can be evaluated unconditionally and its operands are 5110 simple, it wins to evaluate the RHS unconditionally on machines 5111 with expensive branches. In this case, this isn't a comparison 5112 that can be merged. Avoid doing this if the RHS is a floating-point 5113 comparison since those can trap. */ 5114 5115 if (BRANCH_COST >= 2 5116 && ! FLOAT_TYPE_P (TREE_TYPE (rl_arg)) 5117 && simple_operand_p (rl_arg) 5118 && simple_operand_p (rr_arg)) 5119 { 5120 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */ 5121 if (code == TRUTH_OR_EXPR 5122 && lcode == NE_EXPR && integer_zerop (lr_arg) 5123 && rcode == NE_EXPR && integer_zerop (rr_arg) 5124 && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg)) 5125 return build2 (NE_EXPR, truth_type, 5126 build2 (BIT_IOR_EXPR, TREE_TYPE (ll_arg), 5127 ll_arg, rl_arg), 5128 build_int_cst (TREE_TYPE (ll_arg), 0)); 5129 5130 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */ 5131 if (code == TRUTH_AND_EXPR 5132 && lcode == EQ_EXPR && integer_zerop (lr_arg) 5133 && rcode == EQ_EXPR && integer_zerop (rr_arg) 5134 && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg)) 5135 return build2 (EQ_EXPR, truth_type, 5136 build2 (BIT_IOR_EXPR, TREE_TYPE (ll_arg), 5137 ll_arg, rl_arg), 5138 build_int_cst (TREE_TYPE (ll_arg), 0)); 5139 5140 if (LOGICAL_OP_NON_SHORT_CIRCUIT) 5141 { 5142 if (code != orig_code || lhs != orig_lhs || rhs != orig_rhs) 5143 return build2 (code, truth_type, lhs, rhs); 5144 return NULL_TREE; 5145 } 5146 } 5147 5148 /* See if the comparisons can be merged. Then get all the parameters for 5149 each side. */ 5150 5151 if ((lcode != EQ_EXPR && lcode != NE_EXPR) 5152 || (rcode != EQ_EXPR && rcode != NE_EXPR)) 5153 return 0; 5154 5155 volatilep = 0; 5156 ll_inner = decode_field_reference (ll_arg, 5157 &ll_bitsize, &ll_bitpos, &ll_mode, 5158 &ll_unsignedp, &volatilep, &ll_mask, 5159 &ll_and_mask); 5160 lr_inner = decode_field_reference (lr_arg, 5161 &lr_bitsize, &lr_bitpos, &lr_mode, 5162 &lr_unsignedp, &volatilep, &lr_mask, 5163 &lr_and_mask); 5164 rl_inner = decode_field_reference (rl_arg, 5165 &rl_bitsize, &rl_bitpos, &rl_mode, 5166 &rl_unsignedp, &volatilep, &rl_mask, 5167 &rl_and_mask); 5168 rr_inner = decode_field_reference (rr_arg, 5169 &rr_bitsize, &rr_bitpos, &rr_mode, 5170 &rr_unsignedp, &volatilep, &rr_mask, 5171 &rr_and_mask); 5172 5173 /* It must be true that the inner operation on the lhs of each 5174 comparison must be the same if we are to be able to do anything. 5175 Then see if we have constants. If not, the same must be true for 5176 the rhs's. */ 5177 if (volatilep || ll_inner == 0 || rl_inner == 0 5178 || ! operand_equal_p (ll_inner, rl_inner, 0)) 5179 return 0; 5180 5181 if (TREE_CODE (lr_arg) == INTEGER_CST 5182 && TREE_CODE (rr_arg) == INTEGER_CST) 5183 l_const = lr_arg, r_const = rr_arg; 5184 else if (lr_inner == 0 || rr_inner == 0 5185 || ! operand_equal_p (lr_inner, rr_inner, 0)) 5186 return 0; 5187 else 5188 l_const = r_const = 0; 5189 5190 /* If either comparison code is not correct for our logical operation, 5191 fail. However, we can convert a one-bit comparison against zero into 5192 the opposite comparison against that bit being set in the field. */ 5193 5194 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR); 5195 if (lcode != wanted_code) 5196 { 5197 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask)) 5198 { 5199 /* Make the left operand unsigned, since we are only interested 5200 in the value of one bit. Otherwise we are doing the wrong 5201 thing below. */ 5202 ll_unsignedp = 1; 5203 l_const = ll_mask; 5204 } 5205 else 5206 return 0; 5207 } 5208 5209 /* This is analogous to the code for l_const above. */ 5210 if (rcode != wanted_code) 5211 { 5212 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask)) 5213 { 5214 rl_unsignedp = 1; 5215 r_const = rl_mask; 5216 } 5217 else 5218 return 0; 5219 } 5220 5221 /* After this point all optimizations will generate bit-field 5222 references, which we might not want. */ 5223 if (! lang_hooks.can_use_bit_fields_p ()) 5224 return 0; 5225 5226 /* See if we can find a mode that contains both fields being compared on 5227 the left. If we can't, fail. Otherwise, update all constants and masks 5228 to be relative to a field of that size. */ 5229 first_bit = MIN (ll_bitpos, rl_bitpos); 5230 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize); 5231 lnmode = get_best_mode (end_bit - first_bit, first_bit, 5232 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode, 5233 volatilep); 5234 if (lnmode == VOIDmode) 5235 return 0; 5236 5237 lnbitsize = GET_MODE_BITSIZE (lnmode); 5238 lnbitpos = first_bit & ~ (lnbitsize - 1); 5239 lntype = lang_hooks.types.type_for_size (lnbitsize, 1); 5240 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos; 5241 5242 if (BYTES_BIG_ENDIAN) 5243 { 5244 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize; 5245 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize; 5246 } 5247 5248 ll_mask = const_binop (LSHIFT_EXPR, fold_convert (lntype, ll_mask), 5249 size_int (xll_bitpos), 0); 5250 rl_mask = const_binop (LSHIFT_EXPR, fold_convert (lntype, rl_mask), 5251 size_int (xrl_bitpos), 0); 5252 5253 if (l_const) 5254 { 5255 l_const = fold_convert (lntype, l_const); 5256 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask); 5257 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0); 5258 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const, 5259 fold_build1 (BIT_NOT_EXPR, 5260 lntype, ll_mask), 5261 0))) 5262 { 5263 warning (0, "comparison is always %d", wanted_code == NE_EXPR); 5264 5265 return constant_boolean_node (wanted_code == NE_EXPR, truth_type); 5266 } 5267 } 5268 if (r_const) 5269 { 5270 r_const = fold_convert (lntype, r_const); 5271 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask); 5272 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0); 5273 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const, 5274 fold_build1 (BIT_NOT_EXPR, 5275 lntype, rl_mask), 5276 0))) 5277 { 5278 warning (0, "comparison is always %d", wanted_code == NE_EXPR); 5279 5280 return constant_boolean_node (wanted_code == NE_EXPR, truth_type); 5281 } 5282 } 5283 5284 /* If the right sides are not constant, do the same for it. Also, 5285 disallow this optimization if a size or signedness mismatch occurs 5286 between the left and right sides. */ 5287 if (l_const == 0) 5288 { 5289 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize 5290 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp 5291 /* Make sure the two fields on the right 5292 correspond to the left without being swapped. */ 5293 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos) 5294 return 0; 5295 5296 first_bit = MIN (lr_bitpos, rr_bitpos); 5297 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize); 5298 rnmode = get_best_mode (end_bit - first_bit, first_bit, 5299 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode, 5300 volatilep); 5301 if (rnmode == VOIDmode) 5302 return 0; 5303 5304 rnbitsize = GET_MODE_BITSIZE (rnmode); 5305 rnbitpos = first_bit & ~ (rnbitsize - 1); 5306 rntype = lang_hooks.types.type_for_size (rnbitsize, 1); 5307 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos; 5308 5309 if (BYTES_BIG_ENDIAN) 5310 { 5311 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize; 5312 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize; 5313 } 5314 5315 lr_mask = const_binop (LSHIFT_EXPR, fold_convert (rntype, lr_mask), 5316 size_int (xlr_bitpos), 0); 5317 rr_mask = const_binop (LSHIFT_EXPR, fold_convert (rntype, rr_mask), 5318 size_int (xrr_bitpos), 0); 5319 5320 /* Make a mask that corresponds to both fields being compared. 5321 Do this for both items being compared. If the operands are the 5322 same size and the bits being compared are in the same position 5323 then we can do this by masking both and comparing the masked 5324 results. */ 5325 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0); 5326 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0); 5327 if (lnbitsize == rnbitsize && xll_bitpos == xlr_bitpos) 5328 { 5329 lhs = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos, 5330 ll_unsignedp || rl_unsignedp); 5331 if (! all_ones_mask_p (ll_mask, lnbitsize)) 5332 lhs = build2 (BIT_AND_EXPR, lntype, lhs, ll_mask); 5333 5334 rhs = make_bit_field_ref (lr_inner, rntype, rnbitsize, rnbitpos, 5335 lr_unsignedp || rr_unsignedp); 5336 if (! all_ones_mask_p (lr_mask, rnbitsize)) 5337 rhs = build2 (BIT_AND_EXPR, rntype, rhs, lr_mask); 5338 5339 return build2 (wanted_code, truth_type, lhs, rhs); 5340 } 5341 5342 /* There is still another way we can do something: If both pairs of 5343 fields being compared are adjacent, we may be able to make a wider 5344 field containing them both. 5345 5346 Note that we still must mask the lhs/rhs expressions. Furthermore, 5347 the mask must be shifted to account for the shift done by 5348 make_bit_field_ref. */ 5349 if ((ll_bitsize + ll_bitpos == rl_bitpos 5350 && lr_bitsize + lr_bitpos == rr_bitpos) 5351 || (ll_bitpos == rl_bitpos + rl_bitsize 5352 && lr_bitpos == rr_bitpos + rr_bitsize)) 5353 { 5354 tree type; 5355 5356 lhs = make_bit_field_ref (ll_inner, lntype, ll_bitsize + rl_bitsize, 5357 MIN (ll_bitpos, rl_bitpos), ll_unsignedp); 5358 rhs = make_bit_field_ref (lr_inner, rntype, lr_bitsize + rr_bitsize, 5359 MIN (lr_bitpos, rr_bitpos), lr_unsignedp); 5360 5361 ll_mask = const_binop (RSHIFT_EXPR, ll_mask, 5362 size_int (MIN (xll_bitpos, xrl_bitpos)), 0); 5363 lr_mask = const_binop (RSHIFT_EXPR, lr_mask, 5364 size_int (MIN (xlr_bitpos, xrr_bitpos)), 0); 5365 5366 /* Convert to the smaller type before masking out unwanted bits. */ 5367 type = lntype; 5368 if (lntype != rntype) 5369 { 5370 if (lnbitsize > rnbitsize) 5371 { 5372 lhs = fold_convert (rntype, lhs); 5373 ll_mask = fold_convert (rntype, ll_mask); 5374 type = rntype; 5375 } 5376 else if (lnbitsize < rnbitsize) 5377 { 5378 rhs = fold_convert (lntype, rhs); 5379 lr_mask = fold_convert (lntype, lr_mask); 5380 type = lntype; 5381 } 5382 } 5383 5384 if (! all_ones_mask_p (ll_mask, ll_bitsize + rl_bitsize)) 5385 lhs = build2 (BIT_AND_EXPR, type, lhs, ll_mask); 5386 5387 if (! all_ones_mask_p (lr_mask, lr_bitsize + rr_bitsize)) 5388 rhs = build2 (BIT_AND_EXPR, type, rhs, lr_mask); 5389 5390 return build2 (wanted_code, truth_type, lhs, rhs); 5391 } 5392 5393 return 0; 5394 } 5395 5396 /* Handle the case of comparisons with constants. If there is something in 5397 common between the masks, those bits of the constants must be the same. 5398 If not, the condition is always false. Test for this to avoid generating 5399 incorrect code below. */ 5400 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0); 5401 if (! integer_zerop (result) 5402 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0), 5403 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1) 5404 { 5405 if (wanted_code == NE_EXPR) 5406 { 5407 warning (0, "%<or%> of unmatched not-equal tests is always 1"); 5408 return constant_boolean_node (true, truth_type); 5409 } 5410 else 5411 { 5412 warning (0, "%<and%> of mutually exclusive equal-tests is always 0"); 5413 return constant_boolean_node (false, truth_type); 5414 } 5415 } 5416 5417 /* Construct the expression we will return. First get the component 5418 reference we will make. Unless the mask is all ones the width of 5419 that field, perform the mask operation. Then compare with the 5420 merged constant. */ 5421 result = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos, 5422 ll_unsignedp || rl_unsignedp); 5423 5424 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0); 5425 if (! all_ones_mask_p (ll_mask, lnbitsize)) 5426 result = build2 (BIT_AND_EXPR, lntype, result, ll_mask); 5427 5428 return build2 (wanted_code, truth_type, result, 5429 const_binop (BIT_IOR_EXPR, l_const, r_const, 0)); 5430} 5431 5432/* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a 5433 constant. */ 5434 5435static tree 5436optimize_minmax_comparison (enum tree_code code, tree type, tree op0, tree op1) 5437{ 5438 tree arg0 = op0; 5439 enum tree_code op_code; 5440 tree comp_const = op1; 5441 tree minmax_const; 5442 int consts_equal, consts_lt; 5443 tree inner; 5444 5445 STRIP_SIGN_NOPS (arg0); 5446 5447 op_code = TREE_CODE (arg0); 5448 minmax_const = TREE_OPERAND (arg0, 1); 5449 consts_equal = tree_int_cst_equal (minmax_const, comp_const); 5450 consts_lt = tree_int_cst_lt (minmax_const, comp_const); 5451 inner = TREE_OPERAND (arg0, 0); 5452 5453 /* If something does not permit us to optimize, return the original tree. */ 5454 if ((op_code != MIN_EXPR && op_code != MAX_EXPR) 5455 || TREE_CODE (comp_const) != INTEGER_CST 5456 || TREE_CONSTANT_OVERFLOW (comp_const) 5457 || TREE_CODE (minmax_const) != INTEGER_CST 5458 || TREE_CONSTANT_OVERFLOW (minmax_const)) 5459 return NULL_TREE; 5460 5461 /* Now handle all the various comparison codes. We only handle EQ_EXPR 5462 and GT_EXPR, doing the rest with recursive calls using logical 5463 simplifications. */ 5464 switch (code) 5465 { 5466 case NE_EXPR: case LT_EXPR: case LE_EXPR: 5467 { 5468 tree tem = optimize_minmax_comparison (invert_tree_comparison (code, false), 5469 type, op0, op1); 5470 if (tem) 5471 return invert_truthvalue (tem); 5472 return NULL_TREE; 5473 } 5474 5475 case GE_EXPR: 5476 return 5477 fold_build2 (TRUTH_ORIF_EXPR, type, 5478 optimize_minmax_comparison 5479 (EQ_EXPR, type, arg0, comp_const), 5480 optimize_minmax_comparison 5481 (GT_EXPR, type, arg0, comp_const)); 5482 5483 case EQ_EXPR: 5484 if (op_code == MAX_EXPR && consts_equal) 5485 /* MAX (X, 0) == 0 -> X <= 0 */ 5486 return fold_build2 (LE_EXPR, type, inner, comp_const); 5487 5488 else if (op_code == MAX_EXPR && consts_lt) 5489 /* MAX (X, 0) == 5 -> X == 5 */ 5490 return fold_build2 (EQ_EXPR, type, inner, comp_const); 5491 5492 else if (op_code == MAX_EXPR) 5493 /* MAX (X, 0) == -1 -> false */ 5494 return omit_one_operand (type, integer_zero_node, inner); 5495 5496 else if (consts_equal) 5497 /* MIN (X, 0) == 0 -> X >= 0 */ 5498 return fold_build2 (GE_EXPR, type, inner, comp_const); 5499 5500 else if (consts_lt) 5501 /* MIN (X, 0) == 5 -> false */ 5502 return omit_one_operand (type, integer_zero_node, inner); 5503 5504 else 5505 /* MIN (X, 0) == -1 -> X == -1 */ 5506 return fold_build2 (EQ_EXPR, type, inner, comp_const); 5507 5508 case GT_EXPR: 5509 if (op_code == MAX_EXPR && (consts_equal || consts_lt)) 5510 /* MAX (X, 0) > 0 -> X > 0 5511 MAX (X, 0) > 5 -> X > 5 */ 5512 return fold_build2 (GT_EXPR, type, inner, comp_const); 5513 5514 else if (op_code == MAX_EXPR) 5515 /* MAX (X, 0) > -1 -> true */ 5516 return omit_one_operand (type, integer_one_node, inner); 5517 5518 else if (op_code == MIN_EXPR && (consts_equal || consts_lt)) 5519 /* MIN (X, 0) > 0 -> false 5520 MIN (X, 0) > 5 -> false */ 5521 return omit_one_operand (type, integer_zero_node, inner); 5522 5523 else 5524 /* MIN (X, 0) > -1 -> X > -1 */ 5525 return fold_build2 (GT_EXPR, type, inner, comp_const); 5526 5527 default: 5528 return NULL_TREE; 5529 } 5530} 5531 5532/* T is an integer expression that is being multiplied, divided, or taken a 5533 modulus (CODE says which and what kind of divide or modulus) by a 5534 constant C. See if we can eliminate that operation by folding it with 5535 other operations already in T. WIDE_TYPE, if non-null, is a type that 5536 should be used for the computation if wider than our type. 5537 5538 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return 5539 (X * 2) + (Y * 4). We must, however, be assured that either the original 5540 expression would not overflow or that overflow is undefined for the type 5541 in the language in question. 5542 5543 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either 5544 the machine has a multiply-accumulate insn or that this is part of an 5545 addressing calculation. 5546 5547 If we return a non-null expression, it is an equivalent form of the 5548 original computation, but need not be in the original type. 5549 5550 We set *STRICT_OVERFLOW_P to true if the return values depends on 5551 signed overflow being undefined. Otherwise we do not change 5552 *STRICT_OVERFLOW_P. */ 5553 5554static tree 5555extract_muldiv (tree t, tree c, enum tree_code code, tree wide_type, 5556 bool *strict_overflow_p) 5557{ 5558 /* To avoid exponential search depth, refuse to allow recursion past 5559 three levels. Beyond that (1) it's highly unlikely that we'll find 5560 something interesting and (2) we've probably processed it before 5561 when we built the inner expression. */ 5562 5563 static int depth; 5564 tree ret; 5565 5566 if (depth > 3) 5567 return NULL; 5568 5569 depth++; 5570 ret = extract_muldiv_1 (t, c, code, wide_type, strict_overflow_p); 5571 depth--; 5572 5573 return ret; 5574} 5575 5576static tree 5577extract_muldiv_1 (tree t, tree c, enum tree_code code, tree wide_type, 5578 bool *strict_overflow_p) 5579{ 5580 tree type = TREE_TYPE (t); 5581 enum tree_code tcode = TREE_CODE (t); 5582 tree ctype = (wide_type != 0 && (GET_MODE_SIZE (TYPE_MODE (wide_type)) 5583 > GET_MODE_SIZE (TYPE_MODE (type))) 5584 ? wide_type : type); 5585 tree t1, t2; 5586 int same_p = tcode == code; 5587 tree op0 = NULL_TREE, op1 = NULL_TREE; 5588 bool sub_strict_overflow_p; 5589 5590 /* Don't deal with constants of zero here; they confuse the code below. */ 5591 if (integer_zerop (c)) 5592 return NULL_TREE; 5593 5594 if (TREE_CODE_CLASS (tcode) == tcc_unary) 5595 op0 = TREE_OPERAND (t, 0); 5596 5597 if (TREE_CODE_CLASS (tcode) == tcc_binary) 5598 op0 = TREE_OPERAND (t, 0), op1 = TREE_OPERAND (t, 1); 5599 5600 /* Note that we need not handle conditional operations here since fold 5601 already handles those cases. So just do arithmetic here. */ 5602 switch (tcode) 5603 { 5604 case INTEGER_CST: 5605 /* For a constant, we can always simplify if we are a multiply 5606 or (for divide and modulus) if it is a multiple of our constant. */ 5607 if (code == MULT_EXPR 5608 || integer_zerop (const_binop (TRUNC_MOD_EXPR, t, c, 0))) 5609 return const_binop (code, fold_convert (ctype, t), 5610 fold_convert (ctype, c), 0); 5611 break; 5612 5613 case CONVERT_EXPR: case NON_LVALUE_EXPR: case NOP_EXPR: 5614 /* If op0 is an expression ... */ 5615 if ((COMPARISON_CLASS_P (op0) 5616 || UNARY_CLASS_P (op0) 5617 || BINARY_CLASS_P (op0) 5618 || EXPRESSION_CLASS_P (op0)) 5619 /* ... and is unsigned, and its type is smaller than ctype, 5620 then we cannot pass through as widening. */ 5621 && ((TYPE_UNSIGNED (TREE_TYPE (op0)) 5622 && ! (TREE_CODE (TREE_TYPE (op0)) == INTEGER_TYPE 5623 && TYPE_IS_SIZETYPE (TREE_TYPE (op0))) 5624 && (GET_MODE_SIZE (TYPE_MODE (ctype)) 5625 > GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0))))) 5626 /* ... or this is a truncation (t is narrower than op0), 5627 then we cannot pass through this narrowing. */ 5628 || (GET_MODE_SIZE (TYPE_MODE (type)) 5629 < GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0)))) 5630 /* ... or signedness changes for division or modulus, 5631 then we cannot pass through this conversion. */ 5632 || (code != MULT_EXPR 5633 && (TYPE_UNSIGNED (ctype) 5634 != TYPE_UNSIGNED (TREE_TYPE (op0)))))) 5635 break; 5636 5637 /* Pass the constant down and see if we can make a simplification. If 5638 we can, replace this expression with the inner simplification for 5639 possible later conversion to our or some other type. */ 5640 if ((t2 = fold_convert (TREE_TYPE (op0), c)) != 0 5641 && TREE_CODE (t2) == INTEGER_CST 5642 && ! TREE_CONSTANT_OVERFLOW (t2) 5643 && (0 != (t1 = extract_muldiv (op0, t2, code, 5644 code == MULT_EXPR 5645 ? ctype : NULL_TREE, 5646 strict_overflow_p)))) 5647 return t1; 5648 break; 5649 5650 case ABS_EXPR: 5651 /* If widening the type changes it from signed to unsigned, then we 5652 must avoid building ABS_EXPR itself as unsigned. */ 5653 if (TYPE_UNSIGNED (ctype) && !TYPE_UNSIGNED (type)) 5654 { 5655 tree cstype = (*lang_hooks.types.signed_type) (ctype); 5656 if ((t1 = extract_muldiv (op0, c, code, cstype, strict_overflow_p)) 5657 != 0) 5658 { 5659 t1 = fold_build1 (tcode, cstype, fold_convert (cstype, t1)); 5660 return fold_convert (ctype, t1); 5661 } 5662 break; 5663 } 5664 /* If the constant is negative, we cannot simplify this. */ 5665 if (tree_int_cst_sgn (c) == -1) 5666 break; 5667 /* FALLTHROUGH */ 5668 case NEGATE_EXPR: 5669 if ((t1 = extract_muldiv (op0, c, code, wide_type, strict_overflow_p)) 5670 != 0) 5671 return fold_build1 (tcode, ctype, fold_convert (ctype, t1)); 5672 break; 5673 5674 case MIN_EXPR: case MAX_EXPR: 5675 /* If widening the type changes the signedness, then we can't perform 5676 this optimization as that changes the result. */ 5677 if (TYPE_UNSIGNED (ctype) != TYPE_UNSIGNED (type)) 5678 break; 5679 5680 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */ 5681 sub_strict_overflow_p = false; 5682 if ((t1 = extract_muldiv (op0, c, code, wide_type, 5683 &sub_strict_overflow_p)) != 0 5684 && (t2 = extract_muldiv (op1, c, code, wide_type, 5685 &sub_strict_overflow_p)) != 0) 5686 { 5687 if (tree_int_cst_sgn (c) < 0) 5688 tcode = (tcode == MIN_EXPR ? MAX_EXPR : MIN_EXPR); 5689 if (sub_strict_overflow_p) 5690 *strict_overflow_p = true; 5691 return fold_build2 (tcode, ctype, fold_convert (ctype, t1), 5692 fold_convert (ctype, t2)); 5693 } 5694 break; 5695 5696 case LSHIFT_EXPR: case RSHIFT_EXPR: 5697 /* If the second operand is constant, this is a multiplication 5698 or floor division, by a power of two, so we can treat it that 5699 way unless the multiplier or divisor overflows. Signed 5700 left-shift overflow is implementation-defined rather than 5701 undefined in C90, so do not convert signed left shift into 5702 multiplication. */ 5703 if (TREE_CODE (op1) == INTEGER_CST 5704 && (tcode == RSHIFT_EXPR || TYPE_UNSIGNED (TREE_TYPE (op0))) 5705 /* const_binop may not detect overflow correctly, 5706 so check for it explicitly here. */ 5707 && TYPE_PRECISION (TREE_TYPE (size_one_node)) > TREE_INT_CST_LOW (op1) 5708 && TREE_INT_CST_HIGH (op1) == 0 5709 && 0 != (t1 = fold_convert (ctype, 5710 const_binop (LSHIFT_EXPR, 5711 size_one_node, 5712 op1, 0))) 5713 && ! TREE_OVERFLOW (t1)) 5714 return extract_muldiv (build2 (tcode == LSHIFT_EXPR 5715 ? MULT_EXPR : FLOOR_DIV_EXPR, 5716 ctype, fold_convert (ctype, op0), t1), 5717 c, code, wide_type, strict_overflow_p); 5718 break; 5719 5720 case PLUS_EXPR: case MINUS_EXPR: 5721 /* See if we can eliminate the operation on both sides. If we can, we 5722 can return a new PLUS or MINUS. If we can't, the only remaining 5723 cases where we can do anything are if the second operand is a 5724 constant. */ 5725 sub_strict_overflow_p = false; 5726 t1 = extract_muldiv (op0, c, code, wide_type, &sub_strict_overflow_p); 5727 t2 = extract_muldiv (op1, c, code, wide_type, &sub_strict_overflow_p); 5728 if (t1 != 0 && t2 != 0 5729 && (code == MULT_EXPR 5730 /* If not multiplication, we can only do this if both operands 5731 are divisible by c. */ 5732 || (multiple_of_p (ctype, op0, c) 5733 && multiple_of_p (ctype, op1, c)))) 5734 { 5735 if (sub_strict_overflow_p) 5736 *strict_overflow_p = true; 5737 return fold_build2 (tcode, ctype, fold_convert (ctype, t1), 5738 fold_convert (ctype, t2)); 5739 } 5740 5741 /* If this was a subtraction, negate OP1 and set it to be an addition. 5742 This simplifies the logic below. */ 5743 if (tcode == MINUS_EXPR) 5744 tcode = PLUS_EXPR, op1 = negate_expr (op1); 5745 5746 if (TREE_CODE (op1) != INTEGER_CST) 5747 break; 5748 5749 /* If either OP1 or C are negative, this optimization is not safe for 5750 some of the division and remainder types while for others we need 5751 to change the code. */ 5752 if (tree_int_cst_sgn (op1) < 0 || tree_int_cst_sgn (c) < 0) 5753 { 5754 if (code == CEIL_DIV_EXPR) 5755 code = FLOOR_DIV_EXPR; 5756 else if (code == FLOOR_DIV_EXPR) 5757 code = CEIL_DIV_EXPR; 5758 else if (code != MULT_EXPR 5759 && code != CEIL_MOD_EXPR && code != FLOOR_MOD_EXPR) 5760 break; 5761 } 5762 5763 /* If it's a multiply or a division/modulus operation of a multiple 5764 of our constant, do the operation and verify it doesn't overflow. */ 5765 if (code == MULT_EXPR 5766 || integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0))) 5767 { 5768 op1 = const_binop (code, fold_convert (ctype, op1), 5769 fold_convert (ctype, c), 0); 5770 /* We allow the constant to overflow with wrapping semantics. */ 5771 if (op1 == 0 5772 || (TREE_OVERFLOW (op1) && !TYPE_OVERFLOW_WRAPS (ctype))) 5773 break; 5774 } 5775 else 5776 break; 5777 5778 /* If we have an unsigned type is not a sizetype, we cannot widen 5779 the operation since it will change the result if the original 5780 computation overflowed. */ 5781 if (TYPE_UNSIGNED (ctype) 5782 && ! (TREE_CODE (ctype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (ctype)) 5783 && ctype != type) 5784 break; 5785 5786 /* If we were able to eliminate our operation from the first side, 5787 apply our operation to the second side and reform the PLUS. */ 5788 if (t1 != 0 && (TREE_CODE (t1) != code || code == MULT_EXPR)) 5789 return fold_build2 (tcode, ctype, fold_convert (ctype, t1), op1); 5790 5791 /* The last case is if we are a multiply. In that case, we can 5792 apply the distributive law to commute the multiply and addition 5793 if the multiplication of the constants doesn't overflow. */ 5794 if (code == MULT_EXPR) 5795 return fold_build2 (tcode, ctype, 5796 fold_build2 (code, ctype, 5797 fold_convert (ctype, op0), 5798 fold_convert (ctype, c)), 5799 op1); 5800 5801 break; 5802 5803 case MULT_EXPR: 5804 /* We have a special case here if we are doing something like 5805 (C * 8) % 4 since we know that's zero. */ 5806 if ((code == TRUNC_MOD_EXPR || code == CEIL_MOD_EXPR 5807 || code == FLOOR_MOD_EXPR || code == ROUND_MOD_EXPR) 5808 && TREE_CODE (TREE_OPERAND (t, 1)) == INTEGER_CST 5809 && integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0))) 5810 return omit_one_operand (type, integer_zero_node, op0); 5811 5812 /* ... fall through ... */ 5813 5814 case TRUNC_DIV_EXPR: case CEIL_DIV_EXPR: case FLOOR_DIV_EXPR: 5815 case ROUND_DIV_EXPR: case EXACT_DIV_EXPR: 5816 /* If we can extract our operation from the LHS, do so and return a 5817 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise, 5818 do something only if the second operand is a constant. */ 5819 if (same_p 5820 && (t1 = extract_muldiv (op0, c, code, wide_type, 5821 strict_overflow_p)) != 0) 5822 return fold_build2 (tcode, ctype, fold_convert (ctype, t1), 5823 fold_convert (ctype, op1)); 5824 else if (tcode == MULT_EXPR && code == MULT_EXPR 5825 && (t1 = extract_muldiv (op1, c, code, wide_type, 5826 strict_overflow_p)) != 0) 5827 return fold_build2 (tcode, ctype, fold_convert (ctype, op0), 5828 fold_convert (ctype, t1)); 5829 else if (TREE_CODE (op1) != INTEGER_CST) 5830 return 0; 5831 5832 /* If these are the same operation types, we can associate them 5833 assuming no overflow. */ 5834 if (tcode == code 5835 && 0 != (t1 = const_binop (MULT_EXPR, fold_convert (ctype, op1), 5836 fold_convert (ctype, c), 0)) 5837 && ! TREE_OVERFLOW (t1)) 5838 return fold_build2 (tcode, ctype, fold_convert (ctype, op0), t1); 5839 5840 /* If these operations "cancel" each other, we have the main 5841 optimizations of this pass, which occur when either constant is a 5842 multiple of the other, in which case we replace this with either an 5843 operation or CODE or TCODE. 5844 5845 If we have an unsigned type that is not a sizetype, we cannot do 5846 this since it will change the result if the original computation 5847 overflowed. */ 5848 if ((TYPE_OVERFLOW_UNDEFINED (ctype) 5849 || (TREE_CODE (ctype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (ctype))) 5850 && ((code == MULT_EXPR && tcode == EXACT_DIV_EXPR) 5851 || (tcode == MULT_EXPR 5852 && code != TRUNC_MOD_EXPR && code != CEIL_MOD_EXPR 5853 && code != FLOOR_MOD_EXPR && code != ROUND_MOD_EXPR))) 5854 { 5855 if (integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0))) 5856 { 5857 if (TYPE_OVERFLOW_UNDEFINED (ctype)) 5858 *strict_overflow_p = true; 5859 return fold_build2 (tcode, ctype, fold_convert (ctype, op0), 5860 fold_convert (ctype, 5861 const_binop (TRUNC_DIV_EXPR, 5862 op1, c, 0))); 5863 } 5864 else if (integer_zerop (const_binop (TRUNC_MOD_EXPR, c, op1, 0))) 5865 { 5866 if (TYPE_OVERFLOW_UNDEFINED (ctype)) 5867 *strict_overflow_p = true; 5868 return fold_build2 (code, ctype, fold_convert (ctype, op0), 5869 fold_convert (ctype, 5870 const_binop (TRUNC_DIV_EXPR, 5871 c, op1, 0))); 5872 } 5873 } 5874 break; 5875 5876 default: 5877 break; 5878 } 5879 5880 return 0; 5881} 5882 5883/* Return a node which has the indicated constant VALUE (either 0 or 5884 1), and is of the indicated TYPE. */ 5885 5886tree 5887constant_boolean_node (int value, tree type) 5888{ 5889 if (type == integer_type_node) 5890 return value ? integer_one_node : integer_zero_node; 5891 else if (type == boolean_type_node) 5892 return value ? boolean_true_node : boolean_false_node; 5893 else 5894 return build_int_cst (type, value); 5895} 5896 5897 5898/* Return true if expr looks like an ARRAY_REF and set base and 5899 offset to the appropriate trees. If there is no offset, 5900 offset is set to NULL_TREE. Base will be canonicalized to 5901 something you can get the element type from using 5902 TREE_TYPE (TREE_TYPE (base)). Offset will be the offset 5903 in bytes to the base. */ 5904 5905static bool 5906extract_array_ref (tree expr, tree *base, tree *offset) 5907{ 5908 /* One canonical form is a PLUS_EXPR with the first 5909 argument being an ADDR_EXPR with a possible NOP_EXPR 5910 attached. */ 5911 if (TREE_CODE (expr) == PLUS_EXPR) 5912 { 5913 tree op0 = TREE_OPERAND (expr, 0); 5914 tree inner_base, dummy1; 5915 /* Strip NOP_EXPRs here because the C frontends and/or 5916 folders present us (int *)&x.a + 4B possibly. */ 5917 STRIP_NOPS (op0); 5918 if (extract_array_ref (op0, &inner_base, &dummy1)) 5919 { 5920 *base = inner_base; 5921 if (dummy1 == NULL_TREE) 5922 *offset = TREE_OPERAND (expr, 1); 5923 else 5924 *offset = fold_build2 (PLUS_EXPR, TREE_TYPE (expr), 5925 dummy1, TREE_OPERAND (expr, 1)); 5926 return true; 5927 } 5928 } 5929 /* Other canonical form is an ADDR_EXPR of an ARRAY_REF, 5930 which we transform into an ADDR_EXPR with appropriate 5931 offset. For other arguments to the ADDR_EXPR we assume 5932 zero offset and as such do not care about the ADDR_EXPR 5933 type and strip possible nops from it. */ 5934 else if (TREE_CODE (expr) == ADDR_EXPR) 5935 { 5936 tree op0 = TREE_OPERAND (expr, 0); 5937 if (TREE_CODE (op0) == ARRAY_REF) 5938 { 5939 tree idx = TREE_OPERAND (op0, 1); 5940 *base = TREE_OPERAND (op0, 0); 5941 *offset = fold_build2 (MULT_EXPR, TREE_TYPE (idx), idx, 5942 array_ref_element_size (op0)); 5943 } 5944 else 5945 { 5946 /* Handle array-to-pointer decay as &a. */ 5947 if (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE) 5948 *base = TREE_OPERAND (expr, 0); 5949 else 5950 *base = expr; 5951 *offset = NULL_TREE; 5952 } 5953 return true; 5954 } 5955 /* The next canonical form is a VAR_DECL with POINTER_TYPE. */ 5956 else if (SSA_VAR_P (expr) 5957 && TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) 5958 { 5959 *base = expr; 5960 *offset = NULL_TREE; 5961 return true; 5962 } 5963 5964 return false; 5965} 5966 5967 5968/* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'. 5969 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here 5970 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)' 5971 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the 5972 COND is the first argument to CODE; otherwise (as in the example 5973 given here), it is the second argument. TYPE is the type of the 5974 original expression. Return NULL_TREE if no simplification is 5975 possible. */ 5976 5977static tree 5978fold_binary_op_with_conditional_arg (enum tree_code code, 5979 tree type, tree op0, tree op1, 5980 tree cond, tree arg, int cond_first_p) 5981{ 5982 tree cond_type = cond_first_p ? TREE_TYPE (op0) : TREE_TYPE (op1); 5983 tree arg_type = cond_first_p ? TREE_TYPE (op1) : TREE_TYPE (op0); 5984 tree test, true_value, false_value; 5985 tree lhs = NULL_TREE; 5986 tree rhs = NULL_TREE; 5987 5988 /* This transformation is only worthwhile if we don't have to wrap 5989 arg in a SAVE_EXPR, and the operation can be simplified on at least 5990 one of the branches once its pushed inside the COND_EXPR. */ 5991 if (!TREE_CONSTANT (arg)) 5992 return NULL_TREE; 5993 5994 if (TREE_CODE (cond) == COND_EXPR) 5995 { 5996 test = TREE_OPERAND (cond, 0); 5997 true_value = TREE_OPERAND (cond, 1); 5998 false_value = TREE_OPERAND (cond, 2); 5999 /* If this operand throws an expression, then it does not make 6000 sense to try to perform a logical or arithmetic operation 6001 involving it. */ 6002 if (VOID_TYPE_P (TREE_TYPE (true_value))) 6003 lhs = true_value; 6004 if (VOID_TYPE_P (TREE_TYPE (false_value))) 6005 rhs = false_value; 6006 } 6007 else 6008 { 6009 tree testtype = TREE_TYPE (cond); 6010 test = cond; 6011 true_value = constant_boolean_node (true, testtype); 6012 false_value = constant_boolean_node (false, testtype); 6013 } 6014 6015 arg = fold_convert (arg_type, arg); 6016 if (lhs == 0) 6017 { 6018 true_value = fold_convert (cond_type, true_value); 6019 if (cond_first_p) 6020 lhs = fold_build2 (code, type, true_value, arg); 6021 else 6022 lhs = fold_build2 (code, type, arg, true_value); 6023 } 6024 if (rhs == 0) 6025 { 6026 false_value = fold_convert (cond_type, false_value); 6027 if (cond_first_p) 6028 rhs = fold_build2 (code, type, false_value, arg); 6029 else 6030 rhs = fold_build2 (code, type, arg, false_value); 6031 } 6032 6033 test = fold_build3 (COND_EXPR, type, test, lhs, rhs); 6034 return fold_convert (type, test); 6035} 6036 6037 6038/* Subroutine of fold() that checks for the addition of +/- 0.0. 6039 6040 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type 6041 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X - 6042 ADDEND is the same as X. 6043 6044 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero 6045 and finite. The problematic cases are when X is zero, and its mode 6046 has signed zeros. In the case of rounding towards -infinity, 6047 X - 0 is not the same as X because 0 - 0 is -0. In other rounding 6048 modes, X + 0 is not the same as X because -0 + 0 is 0. */ 6049 6050static bool 6051fold_real_zero_addition_p (tree type, tree addend, int negate) 6052{ 6053 if (!real_zerop (addend)) 6054 return false; 6055 6056 /* Don't allow the fold with -fsignaling-nans. */ 6057 if (HONOR_SNANS (TYPE_MODE (type))) 6058 return false; 6059 6060 /* Allow the fold if zeros aren't signed, or their sign isn't important. */ 6061 if (!HONOR_SIGNED_ZEROS (TYPE_MODE (type))) 6062 return true; 6063 6064 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */ 6065 if (TREE_CODE (addend) == REAL_CST 6066 && REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (addend))) 6067 negate = !negate; 6068 6069 /* The mode has signed zeros, and we have to honor their sign. 6070 In this situation, there is only one case we can return true for. 6071 X - 0 is the same as X unless rounding towards -infinity is 6072 supported. */ 6073 return negate && !HONOR_SIGN_DEPENDENT_ROUNDING (TYPE_MODE (type)); 6074} 6075 6076/* Subroutine of fold() that checks comparisons of built-in math 6077 functions against real constants. 6078 6079 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison 6080 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE 6081 is the type of the result and ARG0 and ARG1 are the operands of the 6082 comparison. ARG1 must be a TREE_REAL_CST. 6083 6084 The function returns the constant folded tree if a simplification 6085 can be made, and NULL_TREE otherwise. */ 6086 6087static tree 6088fold_mathfn_compare (enum built_in_function fcode, enum tree_code code, 6089 tree type, tree arg0, tree arg1) 6090{ 6091 REAL_VALUE_TYPE c; 6092 6093 if (BUILTIN_SQRT_P (fcode)) 6094 { 6095 tree arg = TREE_VALUE (TREE_OPERAND (arg0, 1)); 6096 enum machine_mode mode = TYPE_MODE (TREE_TYPE (arg0)); 6097 6098 c = TREE_REAL_CST (arg1); 6099 if (REAL_VALUE_NEGATIVE (c)) 6100 { 6101 /* sqrt(x) < y is always false, if y is negative. */ 6102 if (code == EQ_EXPR || code == LT_EXPR || code == LE_EXPR) 6103 return omit_one_operand (type, integer_zero_node, arg); 6104 6105 /* sqrt(x) > y is always true, if y is negative and we 6106 don't care about NaNs, i.e. negative values of x. */ 6107 if (code == NE_EXPR || !HONOR_NANS (mode)) 6108 return omit_one_operand (type, integer_one_node, arg); 6109 6110 /* sqrt(x) > y is the same as x >= 0, if y is negative. */ 6111 return fold_build2 (GE_EXPR, type, arg, 6112 build_real (TREE_TYPE (arg), dconst0)); 6113 } 6114 else if (code == GT_EXPR || code == GE_EXPR) 6115 { 6116 REAL_VALUE_TYPE c2; 6117 6118 REAL_ARITHMETIC (c2, MULT_EXPR, c, c); 6119 real_convert (&c2, mode, &c2); 6120 6121 if (REAL_VALUE_ISINF (c2)) 6122 { 6123 /* sqrt(x) > y is x == +Inf, when y is very large. */ 6124 if (HONOR_INFINITIES (mode)) 6125 return fold_build2 (EQ_EXPR, type, arg, 6126 build_real (TREE_TYPE (arg), c2)); 6127 6128 /* sqrt(x) > y is always false, when y is very large 6129 and we don't care about infinities. */ 6130 return omit_one_operand (type, integer_zero_node, arg); 6131 } 6132 6133 /* sqrt(x) > c is the same as x > c*c. */ 6134 return fold_build2 (code, type, arg, 6135 build_real (TREE_TYPE (arg), c2)); 6136 } 6137 else if (code == LT_EXPR || code == LE_EXPR) 6138 { 6139 REAL_VALUE_TYPE c2; 6140 6141 REAL_ARITHMETIC (c2, MULT_EXPR, c, c); 6142 real_convert (&c2, mode, &c2); 6143 6144 if (REAL_VALUE_ISINF (c2)) 6145 { 6146 /* sqrt(x) < y is always true, when y is a very large 6147 value and we don't care about NaNs or Infinities. */ 6148 if (! HONOR_NANS (mode) && ! HONOR_INFINITIES (mode)) 6149 return omit_one_operand (type, integer_one_node, arg); 6150 6151 /* sqrt(x) < y is x != +Inf when y is very large and we 6152 don't care about NaNs. */ 6153 if (! HONOR_NANS (mode)) 6154 return fold_build2 (NE_EXPR, type, arg, 6155 build_real (TREE_TYPE (arg), c2)); 6156 6157 /* sqrt(x) < y is x >= 0 when y is very large and we 6158 don't care about Infinities. */ 6159 if (! HONOR_INFINITIES (mode)) 6160 return fold_build2 (GE_EXPR, type, arg, 6161 build_real (TREE_TYPE (arg), dconst0)); 6162 6163 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */ 6164 if (lang_hooks.decls.global_bindings_p () != 0 6165 || CONTAINS_PLACEHOLDER_P (arg)) 6166 return NULL_TREE; 6167 6168 arg = save_expr (arg); 6169 return fold_build2 (TRUTH_ANDIF_EXPR, type, 6170 fold_build2 (GE_EXPR, type, arg, 6171 build_real (TREE_TYPE (arg), 6172 dconst0)), 6173 fold_build2 (NE_EXPR, type, arg, 6174 build_real (TREE_TYPE (arg), 6175 c2))); 6176 } 6177 6178 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */ 6179 if (! HONOR_NANS (mode)) 6180 return fold_build2 (code, type, arg, 6181 build_real (TREE_TYPE (arg), c2)); 6182 6183 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */ 6184 if (lang_hooks.decls.global_bindings_p () == 0 6185 && ! CONTAINS_PLACEHOLDER_P (arg)) 6186 { 6187 arg = save_expr (arg); 6188 return fold_build2 (TRUTH_ANDIF_EXPR, type, 6189 fold_build2 (GE_EXPR, type, arg, 6190 build_real (TREE_TYPE (arg), 6191 dconst0)), 6192 fold_build2 (code, type, arg, 6193 build_real (TREE_TYPE (arg), 6194 c2))); 6195 } 6196 } 6197 } 6198 6199 return NULL_TREE; 6200} 6201 6202/* Subroutine of fold() that optimizes comparisons against Infinities, 6203 either +Inf or -Inf. 6204 6205 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, 6206 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1 6207 are the operands of the comparison. ARG1 must be a TREE_REAL_CST. 6208 6209 The function returns the constant folded tree if a simplification 6210 can be made, and NULL_TREE otherwise. */ 6211 6212static tree 6213fold_inf_compare (enum tree_code code, tree type, tree arg0, tree arg1) 6214{ 6215 enum machine_mode mode; 6216 REAL_VALUE_TYPE max; 6217 tree temp; 6218 bool neg; 6219 6220 mode = TYPE_MODE (TREE_TYPE (arg0)); 6221 6222 /* For negative infinity swap the sense of the comparison. */ 6223 neg = REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg1)); 6224 if (neg) 6225 code = swap_tree_comparison (code); 6226 6227 switch (code) 6228 { 6229 case GT_EXPR: 6230 /* x > +Inf is always false, if with ignore sNANs. */ 6231 if (HONOR_SNANS (mode)) 6232 return NULL_TREE; 6233 return omit_one_operand (type, integer_zero_node, arg0); 6234 6235 case LE_EXPR: 6236 /* x <= +Inf is always true, if we don't case about NaNs. */ 6237 if (! HONOR_NANS (mode)) 6238 return omit_one_operand (type, integer_one_node, arg0); 6239 6240 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */ 6241 if (lang_hooks.decls.global_bindings_p () == 0 6242 && ! CONTAINS_PLACEHOLDER_P (arg0)) 6243 { 6244 arg0 = save_expr (arg0); 6245 return fold_build2 (EQ_EXPR, type, arg0, arg0); 6246 } 6247 break; 6248 6249 case EQ_EXPR: 6250 case GE_EXPR: 6251 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */ 6252 real_maxval (&max, neg, mode); 6253 return fold_build2 (neg ? LT_EXPR : GT_EXPR, type, 6254 arg0, build_real (TREE_TYPE (arg0), max)); 6255 6256 case LT_EXPR: 6257 /* x < +Inf is always equal to x <= DBL_MAX. */ 6258 real_maxval (&max, neg, mode); 6259 return fold_build2 (neg ? GE_EXPR : LE_EXPR, type, 6260 arg0, build_real (TREE_TYPE (arg0), max)); 6261 6262 case NE_EXPR: 6263 /* x != +Inf is always equal to !(x > DBL_MAX). */ 6264 real_maxval (&max, neg, mode); 6265 if (! HONOR_NANS (mode)) 6266 return fold_build2 (neg ? GE_EXPR : LE_EXPR, type, 6267 arg0, build_real (TREE_TYPE (arg0), max)); 6268 6269 /* The transformation below creates non-gimple code and thus is 6270 not appropriate if we are in gimple form. */ 6271 if (in_gimple_form) 6272 return NULL_TREE; 6273 6274 temp = fold_build2 (neg ? LT_EXPR : GT_EXPR, type, 6275 arg0, build_real (TREE_TYPE (arg0), max)); 6276 return fold_build1 (TRUTH_NOT_EXPR, type, temp); 6277 6278 default: 6279 break; 6280 } 6281 6282 return NULL_TREE; 6283} 6284 6285/* Subroutine of fold() that optimizes comparisons of a division by 6286 a nonzero integer constant against an integer constant, i.e. 6287 X/C1 op C2. 6288 6289 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, 6290 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1 6291 are the operands of the comparison. ARG1 must be a TREE_REAL_CST. 6292 6293 The function returns the constant folded tree if a simplification 6294 can be made, and NULL_TREE otherwise. */ 6295 6296static tree 6297fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1) 6298{ 6299 tree prod, tmp, hi, lo; 6300 tree arg00 = TREE_OPERAND (arg0, 0); 6301 tree arg01 = TREE_OPERAND (arg0, 1); 6302 unsigned HOST_WIDE_INT lpart; 6303 HOST_WIDE_INT hpart; 6304 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (arg0)); 6305 bool neg_overflow; 6306 int overflow; 6307 6308 /* We have to do this the hard way to detect unsigned overflow. 6309 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */ 6310 overflow = mul_double_with_sign (TREE_INT_CST_LOW (arg01), 6311 TREE_INT_CST_HIGH (arg01), 6312 TREE_INT_CST_LOW (arg1), 6313 TREE_INT_CST_HIGH (arg1), 6314 &lpart, &hpart, unsigned_p); 6315 prod = build_int_cst_wide (TREE_TYPE (arg00), lpart, hpart); 6316 prod = force_fit_type (prod, -1, overflow, false); 6317 neg_overflow = false; 6318 6319 if (unsigned_p) 6320 { 6321 tmp = int_const_binop (MINUS_EXPR, arg01, integer_one_node, 0); 6322 lo = prod; 6323 6324 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */ 6325 overflow = add_double_with_sign (TREE_INT_CST_LOW (prod), 6326 TREE_INT_CST_HIGH (prod), 6327 TREE_INT_CST_LOW (tmp), 6328 TREE_INT_CST_HIGH (tmp), 6329 &lpart, &hpart, unsigned_p); 6330 hi = build_int_cst_wide (TREE_TYPE (arg00), lpart, hpart); 6331 hi = force_fit_type (hi, -1, overflow | TREE_OVERFLOW (prod), 6332 TREE_CONSTANT_OVERFLOW (prod)); 6333 } 6334 else if (tree_int_cst_sgn (arg01) >= 0) 6335 { 6336 tmp = int_const_binop (MINUS_EXPR, arg01, integer_one_node, 0); 6337 switch (tree_int_cst_sgn (arg1)) 6338 { 6339 case -1: 6340 neg_overflow = true; 6341 lo = int_const_binop (MINUS_EXPR, prod, tmp, 0); 6342 hi = prod; 6343 break; 6344 6345 case 0: 6346 lo = fold_negate_const (tmp, TREE_TYPE (arg0)); 6347 hi = tmp; 6348 break; 6349 6350 case 1: 6351 hi = int_const_binop (PLUS_EXPR, prod, tmp, 0); 6352 lo = prod; 6353 break; 6354 6355 default: 6356 gcc_unreachable (); 6357 } 6358 } 6359 else 6360 { 6361 /* A negative divisor reverses the relational operators. */ 6362 code = swap_tree_comparison (code); 6363 6364 tmp = int_const_binop (PLUS_EXPR, arg01, integer_one_node, 0); 6365 switch (tree_int_cst_sgn (arg1)) 6366 { 6367 case -1: 6368 hi = int_const_binop (MINUS_EXPR, prod, tmp, 0); 6369 lo = prod; 6370 break; 6371 6372 case 0: 6373 hi = fold_negate_const (tmp, TREE_TYPE (arg0)); 6374 lo = tmp; 6375 break; 6376 6377 case 1: 6378 neg_overflow = true; 6379 lo = int_const_binop (PLUS_EXPR, prod, tmp, 0); 6380 hi = prod; 6381 break; 6382 6383 default: 6384 gcc_unreachable (); 6385 } 6386 } 6387 6388 switch (code) 6389 { 6390 case EQ_EXPR: 6391 if (TREE_OVERFLOW (lo) && TREE_OVERFLOW (hi)) 6392 return omit_one_operand (type, integer_zero_node, arg00); 6393 if (TREE_OVERFLOW (hi)) 6394 return fold_build2 (GE_EXPR, type, arg00, lo); 6395 if (TREE_OVERFLOW (lo)) 6396 return fold_build2 (LE_EXPR, type, arg00, hi); 6397 return build_range_check (type, arg00, 1, lo, hi); 6398 6399 case NE_EXPR: 6400 if (TREE_OVERFLOW (lo) && TREE_OVERFLOW (hi)) 6401 return omit_one_operand (type, integer_one_node, arg00); 6402 if (TREE_OVERFLOW (hi)) 6403 return fold_build2 (LT_EXPR, type, arg00, lo); 6404 if (TREE_OVERFLOW (lo)) 6405 return fold_build2 (GT_EXPR, type, arg00, hi); 6406 return build_range_check (type, arg00, 0, lo, hi); 6407 6408 case LT_EXPR: 6409 if (TREE_OVERFLOW (lo)) 6410 { 6411 tmp = neg_overflow ? integer_zero_node : integer_one_node; 6412 return omit_one_operand (type, tmp, arg00); 6413 } 6414 return fold_build2 (LT_EXPR, type, arg00, lo); 6415 6416 case LE_EXPR: 6417 if (TREE_OVERFLOW (hi)) 6418 { 6419 tmp = neg_overflow ? integer_zero_node : integer_one_node; 6420 return omit_one_operand (type, tmp, arg00); 6421 } 6422 return fold_build2 (LE_EXPR, type, arg00, hi); 6423 6424 case GT_EXPR: 6425 if (TREE_OVERFLOW (hi)) 6426 { 6427 tmp = neg_overflow ? integer_one_node : integer_zero_node; 6428 return omit_one_operand (type, tmp, arg00); 6429 } 6430 return fold_build2 (GT_EXPR, type, arg00, hi); 6431 6432 case GE_EXPR: 6433 if (TREE_OVERFLOW (lo)) 6434 { 6435 tmp = neg_overflow ? integer_one_node : integer_zero_node; 6436 return omit_one_operand (type, tmp, arg00); 6437 } 6438 return fold_build2 (GE_EXPR, type, arg00, lo); 6439 6440 default: 6441 break; 6442 } 6443 6444 return NULL_TREE; 6445} 6446 6447 6448/* If CODE with arguments ARG0 and ARG1 represents a single bit 6449 equality/inequality test, then return a simplified form of the test 6450 using a sign testing. Otherwise return NULL. TYPE is the desired 6451 result type. */ 6452 6453static tree 6454fold_single_bit_test_into_sign_test (enum tree_code code, tree arg0, tree arg1, 6455 tree result_type) 6456{ 6457 /* If this is testing a single bit, we can optimize the test. */ 6458 if ((code == NE_EXPR || code == EQ_EXPR) 6459 && TREE_CODE (arg0) == BIT_AND_EXPR && integer_zerop (arg1) 6460 && integer_pow2p (TREE_OPERAND (arg0, 1))) 6461 { 6462 /* If we have (A & C) != 0 where C is the sign bit of A, convert 6463 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */ 6464 tree arg00 = sign_bit_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg0, 1)); 6465 6466 if (arg00 != NULL_TREE 6467 /* This is only a win if casting to a signed type is cheap, 6468 i.e. when arg00's type is not a partial mode. */ 6469 && TYPE_PRECISION (TREE_TYPE (arg00)) 6470 == GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (arg00)))) 6471 { 6472 tree stype = lang_hooks.types.signed_type (TREE_TYPE (arg00)); 6473 return fold_build2 (code == EQ_EXPR ? GE_EXPR : LT_EXPR, 6474 result_type, fold_convert (stype, arg00), 6475 build_int_cst (stype, 0)); 6476 } 6477 } 6478 6479 return NULL_TREE; 6480} 6481 6482/* If CODE with arguments ARG0 and ARG1 represents a single bit 6483 equality/inequality test, then return a simplified form of 6484 the test using shifts and logical operations. Otherwise return 6485 NULL. TYPE is the desired result type. */ 6486 6487tree 6488fold_single_bit_test (enum tree_code code, tree arg0, tree arg1, 6489 tree result_type) 6490{ 6491 /* If this is testing a single bit, we can optimize the test. */ 6492 if ((code == NE_EXPR || code == EQ_EXPR) 6493 && TREE_CODE (arg0) == BIT_AND_EXPR && integer_zerop (arg1) 6494 && integer_pow2p (TREE_OPERAND (arg0, 1))) 6495 { 6496 tree inner = TREE_OPERAND (arg0, 0); 6497 tree type = TREE_TYPE (arg0); 6498 int bitnum = tree_log2 (TREE_OPERAND (arg0, 1)); 6499 enum machine_mode operand_mode = TYPE_MODE (type); 6500 int ops_unsigned; 6501 tree signed_type, unsigned_type, intermediate_type; 6502 tree tem; 6503 6504 /* First, see if we can fold the single bit test into a sign-bit 6505 test. */ 6506 tem = fold_single_bit_test_into_sign_test (code, arg0, arg1, 6507 result_type); 6508 if (tem) 6509 return tem; 6510 6511 /* Otherwise we have (A & C) != 0 where C is a single bit, 6512 convert that into ((A >> C2) & 1). Where C2 = log2(C). 6513 Similarly for (A & C) == 0. */ 6514 6515 /* If INNER is a right shift of a constant and it plus BITNUM does 6516 not overflow, adjust BITNUM and INNER. */ 6517 if (TREE_CODE (inner) == RSHIFT_EXPR 6518 && TREE_CODE (TREE_OPERAND (inner, 1)) == INTEGER_CST 6519 && TREE_INT_CST_HIGH (TREE_OPERAND (inner, 1)) == 0 6520 && bitnum < TYPE_PRECISION (type) 6521 && 0 > compare_tree_int (TREE_OPERAND (inner, 1), 6522 bitnum - TYPE_PRECISION (type))) 6523 { 6524 bitnum += TREE_INT_CST_LOW (TREE_OPERAND (inner, 1)); 6525 inner = TREE_OPERAND (inner, 0); 6526 } 6527 6528 /* If we are going to be able to omit the AND below, we must do our 6529 operations as unsigned. If we must use the AND, we have a choice. 6530 Normally unsigned is faster, but for some machines signed is. */ 6531#ifdef LOAD_EXTEND_OP 6532 ops_unsigned = (LOAD_EXTEND_OP (operand_mode) == SIGN_EXTEND 6533 && !flag_syntax_only) ? 0 : 1; 6534#else 6535 ops_unsigned = 1; 6536#endif 6537 6538 signed_type = lang_hooks.types.type_for_mode (operand_mode, 0); 6539 unsigned_type = lang_hooks.types.type_for_mode (operand_mode, 1); 6540 intermediate_type = ops_unsigned ? unsigned_type : signed_type; 6541 inner = fold_convert (intermediate_type, inner); 6542 6543 if (bitnum != 0) 6544 inner = build2 (RSHIFT_EXPR, intermediate_type, 6545 inner, size_int (bitnum)); 6546 6547 if (code == EQ_EXPR) 6548 inner = fold_build2 (BIT_XOR_EXPR, intermediate_type, 6549 inner, integer_one_node); 6550 6551 /* Put the AND last so it can combine with more things. */ 6552 inner = build2 (BIT_AND_EXPR, intermediate_type, 6553 inner, integer_one_node); 6554 6555 /* Make sure to return the proper type. */ 6556 inner = fold_convert (result_type, inner); 6557 6558 return inner; 6559 } 6560 return NULL_TREE; 6561} 6562 6563/* Check whether we are allowed to reorder operands arg0 and arg1, 6564 such that the evaluation of arg1 occurs before arg0. */ 6565 6566static bool 6567reorder_operands_p (tree arg0, tree arg1) 6568{ 6569 if (! flag_evaluation_order) 6570 return true; 6571 if (TREE_CONSTANT (arg0) || TREE_CONSTANT (arg1)) 6572 return true; 6573 return ! TREE_SIDE_EFFECTS (arg0) 6574 && ! TREE_SIDE_EFFECTS (arg1); 6575} 6576 6577/* Test whether it is preferable two swap two operands, ARG0 and 6578 ARG1, for example because ARG0 is an integer constant and ARG1 6579 isn't. If REORDER is true, only recommend swapping if we can 6580 evaluate the operands in reverse order. */ 6581 6582bool 6583tree_swap_operands_p (tree arg0, tree arg1, bool reorder) 6584{ 6585 STRIP_SIGN_NOPS (arg0); 6586 STRIP_SIGN_NOPS (arg1); 6587 6588 if (TREE_CODE (arg1) == INTEGER_CST) 6589 return 0; 6590 if (TREE_CODE (arg0) == INTEGER_CST) 6591 return 1; 6592 6593 if (TREE_CODE (arg1) == REAL_CST) 6594 return 0; 6595 if (TREE_CODE (arg0) == REAL_CST) 6596 return 1; 6597 6598 if (TREE_CODE (arg1) == COMPLEX_CST) 6599 return 0; 6600 if (TREE_CODE (arg0) == COMPLEX_CST) 6601 return 1; 6602 6603 if (TREE_CONSTANT (arg1)) 6604 return 0; 6605 if (TREE_CONSTANT (arg0)) 6606 return 1; 6607 6608 if (optimize_size) 6609 return 0; 6610 6611 if (reorder && flag_evaluation_order 6612 && (TREE_SIDE_EFFECTS (arg0) || TREE_SIDE_EFFECTS (arg1))) 6613 return 0; 6614 6615 if (DECL_P (arg1)) 6616 return 0; 6617 if (DECL_P (arg0)) 6618 return 1; 6619 6620 /* It is preferable to swap two SSA_NAME to ensure a canonical form 6621 for commutative and comparison operators. Ensuring a canonical 6622 form allows the optimizers to find additional redundancies without 6623 having to explicitly check for both orderings. */ 6624 if (TREE_CODE (arg0) == SSA_NAME 6625 && TREE_CODE (arg1) == SSA_NAME 6626 && SSA_NAME_VERSION (arg0) > SSA_NAME_VERSION (arg1)) 6627 return 1; 6628 6629 return 0; 6630} 6631 6632/* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where 6633 ARG0 is extended to a wider type. */ 6634 6635static tree 6636fold_widened_comparison (enum tree_code code, tree type, tree arg0, tree arg1) 6637{ 6638 tree arg0_unw = get_unwidened (arg0, NULL_TREE); 6639 tree arg1_unw; 6640 tree shorter_type, outer_type; 6641 tree min, max; 6642 bool above, below; 6643 6644 if (arg0_unw == arg0) 6645 return NULL_TREE; 6646 shorter_type = TREE_TYPE (arg0_unw); 6647 6648#ifdef HAVE_canonicalize_funcptr_for_compare 6649 /* Disable this optimization if we're casting a function pointer 6650 type on targets that require function pointer canonicalization. */ 6651 if (HAVE_canonicalize_funcptr_for_compare 6652 && TREE_CODE (shorter_type) == POINTER_TYPE 6653 && TREE_CODE (TREE_TYPE (shorter_type)) == FUNCTION_TYPE) 6654 return NULL_TREE; 6655#endif 6656 6657 if (TYPE_PRECISION (TREE_TYPE (arg0)) <= TYPE_PRECISION (shorter_type)) 6658 return NULL_TREE; 6659 6660 arg1_unw = get_unwidened (arg1, shorter_type); 6661 6662 /* If possible, express the comparison in the shorter mode. */ 6663 if ((code == EQ_EXPR || code == NE_EXPR 6664 || TYPE_UNSIGNED (TREE_TYPE (arg0)) == TYPE_UNSIGNED (shorter_type)) 6665 && (TREE_TYPE (arg1_unw) == shorter_type 6666 || (TREE_CODE (arg1_unw) == INTEGER_CST 6667 && (TREE_CODE (shorter_type) == INTEGER_TYPE 6668 || TREE_CODE (shorter_type) == BOOLEAN_TYPE) 6669 && int_fits_type_p (arg1_unw, shorter_type)))) 6670 return fold_build2 (code, type, arg0_unw, 6671 fold_convert (shorter_type, arg1_unw)); 6672 6673 if (TREE_CODE (arg1_unw) != INTEGER_CST 6674 || TREE_CODE (shorter_type) != INTEGER_TYPE 6675 || !int_fits_type_p (arg1_unw, shorter_type)) 6676 return NULL_TREE; 6677 6678 /* If we are comparing with the integer that does not fit into the range 6679 of the shorter type, the result is known. */ 6680 outer_type = TREE_TYPE (arg1_unw); 6681 min = lower_bound_in_type (outer_type, shorter_type); 6682 max = upper_bound_in_type (outer_type, shorter_type); 6683 6684 above = integer_nonzerop (fold_relational_const (LT_EXPR, type, 6685 max, arg1_unw)); 6686 below = integer_nonzerop (fold_relational_const (LT_EXPR, type, 6687 arg1_unw, min)); 6688 6689 switch (code) 6690 { 6691 case EQ_EXPR: 6692 if (above || below) 6693 return omit_one_operand (type, integer_zero_node, arg0); 6694 break; 6695 6696 case NE_EXPR: 6697 if (above || below) 6698 return omit_one_operand (type, integer_one_node, arg0); 6699 break; 6700 6701 case LT_EXPR: 6702 case LE_EXPR: 6703 if (above) 6704 return omit_one_operand (type, integer_one_node, arg0); 6705 else if (below) 6706 return omit_one_operand (type, integer_zero_node, arg0); 6707 6708 case GT_EXPR: 6709 case GE_EXPR: 6710 if (above) 6711 return omit_one_operand (type, integer_zero_node, arg0); 6712 else if (below) 6713 return omit_one_operand (type, integer_one_node, arg0); 6714 6715 default: 6716 break; 6717 } 6718 6719 return NULL_TREE; 6720} 6721 6722/* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for 6723 ARG0 just the signedness is changed. */ 6724 6725static tree 6726fold_sign_changed_comparison (enum tree_code code, tree type, 6727 tree arg0, tree arg1) 6728{ 6729 tree arg0_inner, tmp; 6730 tree inner_type, outer_type; 6731 6732 if (TREE_CODE (arg0) != NOP_EXPR 6733 && TREE_CODE (arg0) != CONVERT_EXPR) 6734 return NULL_TREE; 6735 6736 outer_type = TREE_TYPE (arg0); 6737 arg0_inner = TREE_OPERAND (arg0, 0); 6738 inner_type = TREE_TYPE (arg0_inner); 6739 6740#ifdef HAVE_canonicalize_funcptr_for_compare 6741 /* Disable this optimization if we're casting a function pointer 6742 type on targets that require function pointer canonicalization. */ 6743 if (HAVE_canonicalize_funcptr_for_compare 6744 && TREE_CODE (inner_type) == POINTER_TYPE 6745 && TREE_CODE (TREE_TYPE (inner_type)) == FUNCTION_TYPE) 6746 return NULL_TREE; 6747#endif 6748 6749 if (TYPE_PRECISION (inner_type) != TYPE_PRECISION (outer_type)) 6750 return NULL_TREE; 6751 6752 if (TREE_CODE (arg1) != INTEGER_CST 6753 && !((TREE_CODE (arg1) == NOP_EXPR 6754 || TREE_CODE (arg1) == CONVERT_EXPR) 6755 && TREE_TYPE (TREE_OPERAND (arg1, 0)) == inner_type)) 6756 return NULL_TREE; 6757 6758 if (TYPE_UNSIGNED (inner_type) != TYPE_UNSIGNED (outer_type) 6759 && code != NE_EXPR 6760 && code != EQ_EXPR) 6761 return NULL_TREE; 6762 6763 if (TREE_CODE (arg1) == INTEGER_CST) 6764 { 6765 tmp = build_int_cst_wide (inner_type, 6766 TREE_INT_CST_LOW (arg1), 6767 TREE_INT_CST_HIGH (arg1)); 6768 arg1 = force_fit_type (tmp, 0, 6769 TREE_OVERFLOW (arg1), 6770 TREE_CONSTANT_OVERFLOW (arg1)); 6771 } 6772 else 6773 arg1 = fold_convert (inner_type, arg1); 6774 6775 return fold_build2 (code, type, arg0_inner, arg1); 6776} 6777 6778/* Tries to replace &a[idx] CODE s * delta with &a[idx CODE delta], if s is 6779 step of the array. Reconstructs s and delta in the case of s * delta 6780 being an integer constant (and thus already folded). 6781 ADDR is the address. MULT is the multiplicative expression. 6782 If the function succeeds, the new address expression is returned. Otherwise 6783 NULL_TREE is returned. */ 6784 6785static tree 6786try_move_mult_to_index (enum tree_code code, tree addr, tree op1) 6787{ 6788 tree s, delta, step; 6789 tree ref = TREE_OPERAND (addr, 0), pref; 6790 tree ret, pos; 6791 tree itype; 6792 6793 /* Canonicalize op1 into a possibly non-constant delta 6794 and an INTEGER_CST s. */ 6795 if (TREE_CODE (op1) == MULT_EXPR) 6796 { 6797 tree arg0 = TREE_OPERAND (op1, 0), arg1 = TREE_OPERAND (op1, 1); 6798 6799 STRIP_NOPS (arg0); 6800 STRIP_NOPS (arg1); 6801 6802 if (TREE_CODE (arg0) == INTEGER_CST) 6803 { 6804 s = arg0; 6805 delta = arg1; 6806 } 6807 else if (TREE_CODE (arg1) == INTEGER_CST) 6808 { 6809 s = arg1; 6810 delta = arg0; 6811 } 6812 else 6813 return NULL_TREE; 6814 } 6815 else if (TREE_CODE (op1) == INTEGER_CST) 6816 { 6817 delta = op1; 6818 s = NULL_TREE; 6819 } 6820 else 6821 { 6822 /* Simulate we are delta * 1. */ 6823 delta = op1; 6824 s = integer_one_node; 6825 } 6826 6827 for (;; ref = TREE_OPERAND (ref, 0)) 6828 { 6829 if (TREE_CODE (ref) == ARRAY_REF) 6830 { 6831 itype = TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (ref, 0))); 6832 if (! itype) 6833 continue; 6834 6835 step = array_ref_element_size (ref); 6836 if (TREE_CODE (step) != INTEGER_CST) 6837 continue; 6838 6839 if (s) 6840 { 6841 if (! tree_int_cst_equal (step, s)) 6842 continue; 6843 } 6844 else 6845 { 6846 /* Try if delta is a multiple of step. */ 6847 tree tmp = div_if_zero_remainder (EXACT_DIV_EXPR, delta, step); 6848 if (! tmp) 6849 continue; 6850 delta = tmp; 6851 } 6852 6853 break; 6854 } 6855 6856 if (!handled_component_p (ref)) 6857 return NULL_TREE; 6858 } 6859 6860 /* We found the suitable array reference. So copy everything up to it, 6861 and replace the index. */ 6862 6863 pref = TREE_OPERAND (addr, 0); 6864 ret = copy_node (pref); 6865 pos = ret; 6866 6867 while (pref != ref) 6868 { 6869 pref = TREE_OPERAND (pref, 0); 6870 TREE_OPERAND (pos, 0) = copy_node (pref); 6871 pos = TREE_OPERAND (pos, 0); 6872 } 6873 6874 TREE_OPERAND (pos, 1) = fold_build2 (code, itype, 6875 fold_convert (itype, 6876 TREE_OPERAND (pos, 1)), 6877 fold_convert (itype, delta)); 6878 6879 return fold_build1 (ADDR_EXPR, TREE_TYPE (addr), ret); 6880} 6881 6882 6883/* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y 6884 means A >= Y && A != MAX, but in this case we know that 6885 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */ 6886 6887static tree 6888fold_to_nonsharp_ineq_using_bound (tree ineq, tree bound) 6889{ 6890 tree a, typea, type = TREE_TYPE (ineq), a1, diff, y; 6891 6892 if (TREE_CODE (bound) == LT_EXPR) 6893 a = TREE_OPERAND (bound, 0); 6894 else if (TREE_CODE (bound) == GT_EXPR) 6895 a = TREE_OPERAND (bound, 1); 6896 else 6897 return NULL_TREE; 6898 6899 typea = TREE_TYPE (a); 6900 if (!INTEGRAL_TYPE_P (typea) 6901 && !POINTER_TYPE_P (typea)) 6902 return NULL_TREE; 6903 6904 if (TREE_CODE (ineq) == LT_EXPR) 6905 { 6906 a1 = TREE_OPERAND (ineq, 1); 6907 y = TREE_OPERAND (ineq, 0); 6908 } 6909 else if (TREE_CODE (ineq) == GT_EXPR) 6910 { 6911 a1 = TREE_OPERAND (ineq, 0); 6912 y = TREE_OPERAND (ineq, 1); 6913 } 6914 else 6915 return NULL_TREE; 6916 6917 if (TREE_TYPE (a1) != typea) 6918 return NULL_TREE; 6919 6920 diff = fold_build2 (MINUS_EXPR, typea, a1, a); 6921 if (!integer_onep (diff)) 6922 return NULL_TREE; 6923 6924 return fold_build2 (GE_EXPR, type, a, y); 6925} 6926 6927/* Fold a sum or difference of at least one multiplication. 6928 Returns the folded tree or NULL if no simplification could be made. */ 6929 6930static tree 6931fold_plusminus_mult_expr (enum tree_code code, tree type, tree arg0, tree arg1) 6932{ 6933 tree arg00, arg01, arg10, arg11; 6934 tree alt0 = NULL_TREE, alt1 = NULL_TREE, same; 6935 6936 /* (A * C) +- (B * C) -> (A+-B) * C. 6937 (A * C) +- A -> A * (C+-1). 6938 We are most concerned about the case where C is a constant, 6939 but other combinations show up during loop reduction. Since 6940 it is not difficult, try all four possibilities. */ 6941 6942 if (TREE_CODE (arg0) == MULT_EXPR) 6943 { 6944 arg00 = TREE_OPERAND (arg0, 0); 6945 arg01 = TREE_OPERAND (arg0, 1); 6946 } 6947 else 6948 { 6949 arg00 = arg0; 6950 arg01 = build_one_cst (type); 6951 } 6952 if (TREE_CODE (arg1) == MULT_EXPR) 6953 { 6954 arg10 = TREE_OPERAND (arg1, 0); 6955 arg11 = TREE_OPERAND (arg1, 1); 6956 } 6957 else 6958 { 6959 arg10 = arg1; 6960 arg11 = build_one_cst (type); 6961 } 6962 same = NULL_TREE; 6963 6964 if (operand_equal_p (arg01, arg11, 0)) 6965 same = arg01, alt0 = arg00, alt1 = arg10; 6966 else if (operand_equal_p (arg00, arg10, 0)) 6967 same = arg00, alt0 = arg01, alt1 = arg11; 6968 else if (operand_equal_p (arg00, arg11, 0)) 6969 same = arg00, alt0 = arg01, alt1 = arg10; 6970 else if (operand_equal_p (arg01, arg10, 0)) 6971 same = arg01, alt0 = arg00, alt1 = arg11; 6972 6973 /* No identical multiplicands; see if we can find a common 6974 power-of-two factor in non-power-of-two multiplies. This 6975 can help in multi-dimensional array access. */ 6976 else if (host_integerp (arg01, 0) 6977 && host_integerp (arg11, 0)) 6978 { 6979 HOST_WIDE_INT int01, int11, tmp; 6980 bool swap = false; 6981 tree maybe_same; 6982 int01 = TREE_INT_CST_LOW (arg01); 6983 int11 = TREE_INT_CST_LOW (arg11); 6984 6985 /* Move min of absolute values to int11. */ 6986 if ((int01 >= 0 ? int01 : -int01) 6987 < (int11 >= 0 ? int11 : -int11)) 6988 { 6989 tmp = int01, int01 = int11, int11 = tmp; 6990 alt0 = arg00, arg00 = arg10, arg10 = alt0; 6991 maybe_same = arg01; 6992 swap = true; 6993 } 6994 else 6995 maybe_same = arg11; 6996 6997 if (exact_log2 (int11) > 0 && int01 % int11 == 0) 6998 { 6999 alt0 = fold_build2 (MULT_EXPR, TREE_TYPE (arg00), arg00, 7000 build_int_cst (TREE_TYPE (arg00), 7001 int01 / int11)); 7002 alt1 = arg10; 7003 same = maybe_same; 7004 if (swap) 7005 maybe_same = alt0, alt0 = alt1, alt1 = maybe_same; 7006 } 7007 } 7008 7009 if (same) 7010 return fold_build2 (MULT_EXPR, type, 7011 fold_build2 (code, type, 7012 fold_convert (type, alt0), 7013 fold_convert (type, alt1)), 7014 fold_convert (type, same)); 7015 7016 return NULL_TREE; 7017} 7018 7019/* Subroutine of native_encode_expr. Encode the INTEGER_CST 7020 specified by EXPR into the buffer PTR of length LEN bytes. 7021 Return the number of bytes placed in the buffer, or zero 7022 upon failure. */ 7023 7024static int 7025native_encode_int (tree expr, unsigned char *ptr, int len) 7026{ 7027 tree type = TREE_TYPE (expr); 7028 int total_bytes = GET_MODE_SIZE (TYPE_MODE (type)); 7029 int byte, offset, word, words; 7030 unsigned char value; 7031 7032 if (total_bytes > len) 7033 return 0; 7034 words = total_bytes / UNITS_PER_WORD; 7035 7036 for (byte = 0; byte < total_bytes; byte++) 7037 { 7038 int bitpos = byte * BITS_PER_UNIT; 7039 if (bitpos < HOST_BITS_PER_WIDE_INT) 7040 value = (unsigned char) (TREE_INT_CST_LOW (expr) >> bitpos); 7041 else 7042 value = (unsigned char) (TREE_INT_CST_HIGH (expr) 7043 >> (bitpos - HOST_BITS_PER_WIDE_INT)); 7044 7045 if (total_bytes > UNITS_PER_WORD) 7046 { 7047 word = byte / UNITS_PER_WORD; 7048 if (WORDS_BIG_ENDIAN) 7049 word = (words - 1) - word; 7050 offset = word * UNITS_PER_WORD; 7051 if (BYTES_BIG_ENDIAN) 7052 offset += (UNITS_PER_WORD - 1) - (byte % UNITS_PER_WORD); 7053 else 7054 offset += byte % UNITS_PER_WORD; 7055 } 7056 else 7057 offset = BYTES_BIG_ENDIAN ? (total_bytes - 1) - byte : byte; 7058 ptr[offset] = value; 7059 } 7060 return total_bytes; 7061} 7062 7063 7064/* Subroutine of native_encode_expr. Encode the REAL_CST 7065 specified by EXPR into the buffer PTR of length LEN bytes. 7066 Return the number of bytes placed in the buffer, or zero 7067 upon failure. */ 7068 7069static int 7070native_encode_real (tree expr, unsigned char *ptr, int len) 7071{ 7072 tree type = TREE_TYPE (expr); 7073 int total_bytes = GET_MODE_SIZE (TYPE_MODE (type)); 7074 int byte, offset, word, words, bitpos; 7075 unsigned char value; 7076 7077 /* There are always 32 bits in each long, no matter the size of 7078 the hosts long. We handle floating point representations with 7079 up to 192 bits. */ 7080 long tmp[6]; 7081 7082 if (total_bytes > len) 7083 return 0; 7084 words = 32 / UNITS_PER_WORD; 7085 7086 real_to_target (tmp, TREE_REAL_CST_PTR (expr), TYPE_MODE (type)); 7087 7088 for (bitpos = 0; bitpos < total_bytes * BITS_PER_UNIT; 7089 bitpos += BITS_PER_UNIT) 7090 { 7091 byte = (bitpos / BITS_PER_UNIT) & 3; 7092 value = (unsigned char) (tmp[bitpos / 32] >> (bitpos & 31)); 7093 7094 if (UNITS_PER_WORD < 4) 7095 { 7096 word = byte / UNITS_PER_WORD; 7097 if (WORDS_BIG_ENDIAN) 7098 word = (words - 1) - word; 7099 offset = word * UNITS_PER_WORD; 7100 if (BYTES_BIG_ENDIAN) 7101 offset += (UNITS_PER_WORD - 1) - (byte % UNITS_PER_WORD); 7102 else 7103 offset += byte % UNITS_PER_WORD; 7104 } 7105 else 7106 offset = BYTES_BIG_ENDIAN ? 3 - byte : byte; 7107 ptr[offset + ((bitpos / BITS_PER_UNIT) & ~3)] = value; 7108 } 7109 return total_bytes; 7110} 7111 7112/* Subroutine of native_encode_expr. Encode the COMPLEX_CST 7113 specified by EXPR into the buffer PTR of length LEN bytes. 7114 Return the number of bytes placed in the buffer, or zero 7115 upon failure. */ 7116 7117static int 7118native_encode_complex (tree expr, unsigned char *ptr, int len) 7119{ 7120 int rsize, isize; 7121 tree part; 7122 7123 part = TREE_REALPART (expr); 7124 rsize = native_encode_expr (part, ptr, len); 7125 if (rsize == 0) 7126 return 0; 7127 part = TREE_IMAGPART (expr); 7128 isize = native_encode_expr (part, ptr+rsize, len-rsize); 7129 if (isize != rsize) 7130 return 0; 7131 return rsize + isize; 7132} 7133 7134 7135/* Subroutine of native_encode_expr. Encode the VECTOR_CST 7136 specified by EXPR into the buffer PTR of length LEN bytes. 7137 Return the number of bytes placed in the buffer, or zero 7138 upon failure. */ 7139 7140static int 7141native_encode_vector (tree expr, unsigned char *ptr, int len) 7142{ 7143 int i, size, offset, count; 7144 tree itype, elem, elements; 7145 7146 offset = 0; 7147 elements = TREE_VECTOR_CST_ELTS (expr); 7148 count = TYPE_VECTOR_SUBPARTS (TREE_TYPE (expr)); 7149 itype = TREE_TYPE (TREE_TYPE (expr)); 7150 size = GET_MODE_SIZE (TYPE_MODE (itype)); 7151 for (i = 0; i < count; i++) 7152 { 7153 if (elements) 7154 { 7155 elem = TREE_VALUE (elements); 7156 elements = TREE_CHAIN (elements); 7157 } 7158 else 7159 elem = NULL_TREE; 7160 7161 if (elem) 7162 { 7163 if (native_encode_expr (elem, ptr+offset, len-offset) != size) 7164 return 0; 7165 } 7166 else 7167 { 7168 if (offset + size > len) 7169 return 0; 7170 memset (ptr+offset, 0, size); 7171 } 7172 offset += size; 7173 } 7174 return offset; 7175} 7176 7177 7178/* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, 7179 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the 7180 buffer PTR of length LEN bytes. Return the number of bytes 7181 placed in the buffer, or zero upon failure. */ 7182 7183static int 7184native_encode_expr (tree expr, unsigned char *ptr, int len) 7185{ 7186 switch (TREE_CODE (expr)) 7187 { 7188 case INTEGER_CST: 7189 return native_encode_int (expr, ptr, len); 7190 7191 case REAL_CST: 7192 return native_encode_real (expr, ptr, len); 7193 7194 case COMPLEX_CST: 7195 return native_encode_complex (expr, ptr, len); 7196 7197 case VECTOR_CST: 7198 return native_encode_vector (expr, ptr, len); 7199 7200 default: 7201 return 0; 7202 } 7203} 7204 7205 7206/* Subroutine of native_interpret_expr. Interpret the contents of 7207 the buffer PTR of length LEN as an INTEGER_CST of type TYPE. 7208 If the buffer cannot be interpreted, return NULL_TREE. */ 7209 7210static tree 7211native_interpret_int (tree type, unsigned char *ptr, int len) 7212{ 7213 int total_bytes = GET_MODE_SIZE (TYPE_MODE (type)); 7214 int byte, offset, word, words; 7215 unsigned char value; 7216 unsigned int HOST_WIDE_INT lo = 0; 7217 HOST_WIDE_INT hi = 0; 7218 7219 if (total_bytes > len) 7220 return NULL_TREE; 7221 if (total_bytes * BITS_PER_UNIT > 2 * HOST_BITS_PER_WIDE_INT) 7222 return NULL_TREE; 7223 words = total_bytes / UNITS_PER_WORD; 7224 7225 for (byte = 0; byte < total_bytes; byte++) 7226 { 7227 int bitpos = byte * BITS_PER_UNIT; 7228 if (total_bytes > UNITS_PER_WORD) 7229 { 7230 word = byte / UNITS_PER_WORD; 7231 if (WORDS_BIG_ENDIAN) 7232 word = (words - 1) - word; 7233 offset = word * UNITS_PER_WORD; 7234 if (BYTES_BIG_ENDIAN) 7235 offset += (UNITS_PER_WORD - 1) - (byte % UNITS_PER_WORD); 7236 else 7237 offset += byte % UNITS_PER_WORD; 7238 } 7239 else 7240 offset = BYTES_BIG_ENDIAN ? (total_bytes - 1) - byte : byte; 7241 value = ptr[offset]; 7242 7243 if (bitpos < HOST_BITS_PER_WIDE_INT) 7244 lo |= (unsigned HOST_WIDE_INT) value << bitpos; 7245 else 7246 hi |= (unsigned HOST_WIDE_INT) value 7247 << (bitpos - HOST_BITS_PER_WIDE_INT); 7248 } 7249 7250 return force_fit_type (build_int_cst_wide (type, lo, hi), 7251 0, false, false); 7252} 7253 7254 7255/* Subroutine of native_interpret_expr. Interpret the contents of 7256 the buffer PTR of length LEN as a REAL_CST of type TYPE. 7257 If the buffer cannot be interpreted, return NULL_TREE. */ 7258 7259static tree 7260native_interpret_real (tree type, unsigned char *ptr, int len) 7261{ 7262 enum machine_mode mode = TYPE_MODE (type); 7263 int total_bytes = GET_MODE_SIZE (mode); 7264 int byte, offset, word, words, bitpos; 7265 unsigned char value; 7266 /* There are always 32 bits in each long, no matter the size of 7267 the hosts long. We handle floating point representations with 7268 up to 192 bits. */ 7269 REAL_VALUE_TYPE r; 7270 long tmp[6]; 7271 7272 total_bytes = GET_MODE_SIZE (TYPE_MODE (type)); 7273 if (total_bytes > len || total_bytes > 24) 7274 return NULL_TREE; 7275 words = 32 / UNITS_PER_WORD; 7276 7277 memset (tmp, 0, sizeof (tmp)); 7278 for (bitpos = 0; bitpos < total_bytes * BITS_PER_UNIT; 7279 bitpos += BITS_PER_UNIT) 7280 { 7281 byte = (bitpos / BITS_PER_UNIT) & 3; 7282 if (UNITS_PER_WORD < 4) 7283 { 7284 word = byte / UNITS_PER_WORD; 7285 if (WORDS_BIG_ENDIAN) 7286 word = (words - 1) - word; 7287 offset = word * UNITS_PER_WORD; 7288 if (BYTES_BIG_ENDIAN) 7289 offset += (UNITS_PER_WORD - 1) - (byte % UNITS_PER_WORD); 7290 else 7291 offset += byte % UNITS_PER_WORD; 7292 } 7293 else 7294 offset = BYTES_BIG_ENDIAN ? 3 - byte : byte; 7295 value = ptr[offset + ((bitpos / BITS_PER_UNIT) & ~3)]; 7296 7297 tmp[bitpos / 32] |= (unsigned long)value << (bitpos & 31); 7298 } 7299 7300 real_from_target (&r, tmp, mode); 7301 return build_real (type, r); 7302} 7303 7304 7305/* Subroutine of native_interpret_expr. Interpret the contents of 7306 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE. 7307 If the buffer cannot be interpreted, return NULL_TREE. */ 7308 7309static tree 7310native_interpret_complex (tree type, unsigned char *ptr, int len) 7311{ 7312 tree etype, rpart, ipart; 7313 int size; 7314 7315 etype = TREE_TYPE (type); 7316 size = GET_MODE_SIZE (TYPE_MODE (etype)); 7317 if (size * 2 > len) 7318 return NULL_TREE; 7319 rpart = native_interpret_expr (etype, ptr, size); 7320 if (!rpart) 7321 return NULL_TREE; 7322 ipart = native_interpret_expr (etype, ptr+size, size); 7323 if (!ipart) 7324 return NULL_TREE; 7325 return build_complex (type, rpart, ipart); 7326} 7327 7328 7329/* Subroutine of native_interpret_expr. Interpret the contents of 7330 the buffer PTR of length LEN as a VECTOR_CST of type TYPE. 7331 If the buffer cannot be interpreted, return NULL_TREE. */ 7332 7333static tree 7334native_interpret_vector (tree type, unsigned char *ptr, int len) 7335{ 7336 tree etype, elem, elements; 7337 int i, size, count; 7338 7339 etype = TREE_TYPE (type); 7340 size = GET_MODE_SIZE (TYPE_MODE (etype)); 7341 count = TYPE_VECTOR_SUBPARTS (type); 7342 if (size * count > len) 7343 return NULL_TREE; 7344 7345 elements = NULL_TREE; 7346 for (i = count - 1; i >= 0; i--) 7347 { 7348 elem = native_interpret_expr (etype, ptr+(i*size), size); 7349 if (!elem) 7350 return NULL_TREE; 7351 elements = tree_cons (NULL_TREE, elem, elements); 7352 } 7353 return build_vector (type, elements); 7354} 7355 7356 7357/* Subroutine of fold_view_convert_expr. Interpret the contents of 7358 the buffer PTR of length LEN as a constant of type TYPE. For 7359 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P 7360 we return a REAL_CST, etc... If the buffer cannot be interpreted, 7361 return NULL_TREE. */ 7362 7363static tree 7364native_interpret_expr (tree type, unsigned char *ptr, int len) 7365{ 7366 switch (TREE_CODE (type)) 7367 { 7368 case INTEGER_TYPE: 7369 case ENUMERAL_TYPE: 7370 case BOOLEAN_TYPE: 7371 return native_interpret_int (type, ptr, len); 7372 7373 case REAL_TYPE: 7374 return native_interpret_real (type, ptr, len); 7375 7376 case COMPLEX_TYPE: 7377 return native_interpret_complex (type, ptr, len); 7378 7379 case VECTOR_TYPE: 7380 return native_interpret_vector (type, ptr, len); 7381 7382 default: 7383 return NULL_TREE; 7384 } 7385} 7386 7387 7388/* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type 7389 TYPE at compile-time. If we're unable to perform the conversion 7390 return NULL_TREE. */ 7391 7392static tree 7393fold_view_convert_expr (tree type, tree expr) 7394{ 7395 /* We support up to 512-bit values (for V8DFmode). */ 7396 unsigned char buffer[64]; 7397 int len; 7398 7399 /* Check that the host and target are sane. */ 7400 if (CHAR_BIT != 8 || BITS_PER_UNIT != 8) 7401 return NULL_TREE; 7402 7403 len = native_encode_expr (expr, buffer, sizeof (buffer)); 7404 if (len == 0) 7405 return NULL_TREE; 7406 7407 return native_interpret_expr (type, buffer, len); 7408} 7409 7410 7411/* Fold a unary expression of code CODE and type TYPE with operand 7412 OP0. Return the folded expression if folding is successful. 7413 Otherwise, return NULL_TREE. */ 7414 7415tree 7416fold_unary (enum tree_code code, tree type, tree op0) 7417{ 7418 tree tem; 7419 tree arg0; 7420 enum tree_code_class kind = TREE_CODE_CLASS (code); 7421 7422 gcc_assert (IS_EXPR_CODE_CLASS (kind) 7423 && TREE_CODE_LENGTH (code) == 1); 7424 7425 arg0 = op0; 7426 if (arg0) 7427 { 7428 if (code == NOP_EXPR || code == CONVERT_EXPR 7429 || code == FLOAT_EXPR || code == ABS_EXPR) 7430 { 7431 /* Don't use STRIP_NOPS, because signedness of argument type 7432 matters. */ 7433 STRIP_SIGN_NOPS (arg0); 7434 } 7435 else 7436 { 7437 /* Strip any conversions that don't change the mode. This 7438 is safe for every expression, except for a comparison 7439 expression because its signedness is derived from its 7440 operands. 7441 7442 Note that this is done as an internal manipulation within 7443 the constant folder, in order to find the simplest 7444 representation of the arguments so that their form can be 7445 studied. In any cases, the appropriate type conversions 7446 should be put back in the tree that will get out of the 7447 constant folder. */ 7448 STRIP_NOPS (arg0); 7449 } 7450 } 7451 7452 if (TREE_CODE_CLASS (code) == tcc_unary) 7453 { 7454 if (TREE_CODE (arg0) == COMPOUND_EXPR) 7455 return build2 (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), 7456 fold_build1 (code, type, TREE_OPERAND (arg0, 1))); 7457 else if (TREE_CODE (arg0) == COND_EXPR) 7458 { 7459 tree arg01 = TREE_OPERAND (arg0, 1); 7460 tree arg02 = TREE_OPERAND (arg0, 2); 7461 if (! VOID_TYPE_P (TREE_TYPE (arg01))) 7462 arg01 = fold_build1 (code, type, arg01); 7463 if (! VOID_TYPE_P (TREE_TYPE (arg02))) 7464 arg02 = fold_build1 (code, type, arg02); 7465 tem = fold_build3 (COND_EXPR, type, TREE_OPERAND (arg0, 0), 7466 arg01, arg02); 7467 7468 /* If this was a conversion, and all we did was to move into 7469 inside the COND_EXPR, bring it back out. But leave it if 7470 it is a conversion from integer to integer and the 7471 result precision is no wider than a word since such a 7472 conversion is cheap and may be optimized away by combine, 7473 while it couldn't if it were outside the COND_EXPR. Then return 7474 so we don't get into an infinite recursion loop taking the 7475 conversion out and then back in. */ 7476 7477 if ((code == NOP_EXPR || code == CONVERT_EXPR 7478 || code == NON_LVALUE_EXPR) 7479 && TREE_CODE (tem) == COND_EXPR 7480 && TREE_CODE (TREE_OPERAND (tem, 1)) == code 7481 && TREE_CODE (TREE_OPERAND (tem, 2)) == code 7482 && ! VOID_TYPE_P (TREE_OPERAND (tem, 1)) 7483 && ! VOID_TYPE_P (TREE_OPERAND (tem, 2)) 7484 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (tem, 1), 0)) 7485 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (tem, 2), 0))) 7486 && (! (INTEGRAL_TYPE_P (TREE_TYPE (tem)) 7487 && (INTEGRAL_TYPE_P 7488 (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (tem, 1), 0)))) 7489 && TYPE_PRECISION (TREE_TYPE (tem)) <= BITS_PER_WORD) 7490 || flag_syntax_only)) 7491 tem = build1 (code, type, 7492 build3 (COND_EXPR, 7493 TREE_TYPE (TREE_OPERAND 7494 (TREE_OPERAND (tem, 1), 0)), 7495 TREE_OPERAND (tem, 0), 7496 TREE_OPERAND (TREE_OPERAND (tem, 1), 0), 7497 TREE_OPERAND (TREE_OPERAND (tem, 2), 0))); 7498 return tem; 7499 } 7500 else if (COMPARISON_CLASS_P (arg0)) 7501 { 7502 if (TREE_CODE (type) == BOOLEAN_TYPE) 7503 { 7504 arg0 = copy_node (arg0); 7505 TREE_TYPE (arg0) = type; 7506 return arg0; 7507 } 7508 else if (TREE_CODE (type) != INTEGER_TYPE) 7509 return fold_build3 (COND_EXPR, type, arg0, 7510 fold_build1 (code, type, 7511 integer_one_node), 7512 fold_build1 (code, type, 7513 integer_zero_node)); 7514 } 7515 } 7516 7517 switch (code) 7518 { 7519 case NOP_EXPR: 7520 case FLOAT_EXPR: 7521 case CONVERT_EXPR: 7522 case FIX_TRUNC_EXPR: 7523 case FIX_CEIL_EXPR: 7524 case FIX_FLOOR_EXPR: 7525 case FIX_ROUND_EXPR: 7526 if (TREE_TYPE (op0) == type) 7527 return op0; 7528 7529 /* If we have (type) (a CMP b) and type is an integral type, return 7530 new expression involving the new type. */ 7531 if (COMPARISON_CLASS_P (op0) && INTEGRAL_TYPE_P (type)) 7532 return fold_build2 (TREE_CODE (op0), type, TREE_OPERAND (op0, 0), 7533 TREE_OPERAND (op0, 1)); 7534 7535 /* Handle cases of two conversions in a row. */ 7536 if (TREE_CODE (op0) == NOP_EXPR 7537 || TREE_CODE (op0) == CONVERT_EXPR) 7538 { 7539 tree inside_type = TREE_TYPE (TREE_OPERAND (op0, 0)); 7540 tree inter_type = TREE_TYPE (op0); 7541 int inside_int = INTEGRAL_TYPE_P (inside_type); 7542 int inside_ptr = POINTER_TYPE_P (inside_type); 7543 int inside_float = FLOAT_TYPE_P (inside_type); 7544 int inside_vec = TREE_CODE (inside_type) == VECTOR_TYPE; 7545 unsigned int inside_prec = TYPE_PRECISION (inside_type); 7546 int inside_unsignedp = TYPE_UNSIGNED (inside_type); 7547 int inter_int = INTEGRAL_TYPE_P (inter_type); 7548 int inter_ptr = POINTER_TYPE_P (inter_type); 7549 int inter_float = FLOAT_TYPE_P (inter_type); 7550 int inter_vec = TREE_CODE (inter_type) == VECTOR_TYPE; 7551 unsigned int inter_prec = TYPE_PRECISION (inter_type); 7552 int inter_unsignedp = TYPE_UNSIGNED (inter_type); 7553 int final_int = INTEGRAL_TYPE_P (type); 7554 int final_ptr = POINTER_TYPE_P (type); 7555 int final_float = FLOAT_TYPE_P (type); 7556 int final_vec = TREE_CODE (type) == VECTOR_TYPE; 7557 unsigned int final_prec = TYPE_PRECISION (type); 7558 int final_unsignedp = TYPE_UNSIGNED (type); 7559 7560 /* In addition to the cases of two conversions in a row 7561 handled below, if we are converting something to its own 7562 type via an object of identical or wider precision, neither 7563 conversion is needed. */ 7564 if (TYPE_MAIN_VARIANT (inside_type) == TYPE_MAIN_VARIANT (type) 7565 && (((inter_int || inter_ptr) && final_int) 7566 || (inter_float && final_float)) 7567 && inter_prec >= final_prec) 7568 return fold_build1 (code, type, TREE_OPERAND (op0, 0)); 7569 7570 /* Likewise, if the intermediate and final types are either both 7571 float or both integer, we don't need the middle conversion if 7572 it is wider than the final type and doesn't change the signedness 7573 (for integers). Avoid this if the final type is a pointer 7574 since then we sometimes need the inner conversion. Likewise if 7575 the outer has a precision not equal to the size of its mode. */ 7576 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr)) 7577 || (inter_float && inside_float) 7578 || (inter_vec && inside_vec)) 7579 && inter_prec >= inside_prec 7580 && (inter_float || inter_vec 7581 || inter_unsignedp == inside_unsignedp) 7582 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (type)) 7583 && TYPE_MODE (type) == TYPE_MODE (inter_type)) 7584 && ! final_ptr 7585 && (! final_vec || inter_prec == inside_prec)) 7586 return fold_build1 (code, type, TREE_OPERAND (op0, 0)); 7587 7588 /* If we have a sign-extension of a zero-extended value, we can 7589 replace that by a single zero-extension. */ 7590 if (inside_int && inter_int && final_int 7591 && inside_prec < inter_prec && inter_prec < final_prec 7592 && inside_unsignedp && !inter_unsignedp) 7593 return fold_build1 (code, type, TREE_OPERAND (op0, 0)); 7594 7595 /* Two conversions in a row are not needed unless: 7596 - some conversion is floating-point (overstrict for now), or 7597 - some conversion is a vector (overstrict for now), or 7598 - the intermediate type is narrower than both initial and 7599 final, or 7600 - the intermediate type and innermost type differ in signedness, 7601 and the outermost type is wider than the intermediate, or 7602 - the initial type is a pointer type and the precisions of the 7603 intermediate and final types differ, or 7604 - the final type is a pointer type and the precisions of the 7605 initial and intermediate types differ. 7606 - the final type is a pointer type and the initial type not 7607 - the initial type is a pointer to an array and the final type 7608 not. */ 7609 /* Java pointer type conversions generate checks in some 7610 cases, so we explicitly disallow this optimization. */ 7611 if (! inside_float && ! inter_float && ! final_float 7612 && ! inside_vec && ! inter_vec && ! final_vec 7613 && (inter_prec >= inside_prec || inter_prec >= final_prec) 7614 && ! (inside_int && inter_int 7615 && inter_unsignedp != inside_unsignedp 7616 && inter_prec < final_prec) 7617 && ((inter_unsignedp && inter_prec > inside_prec) 7618 == (final_unsignedp && final_prec > inter_prec)) 7619 && ! (inside_ptr && inter_prec != final_prec) 7620 && ! (final_ptr && inside_prec != inter_prec) 7621 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (type)) 7622 && TYPE_MODE (type) == TYPE_MODE (inter_type)) 7623 && final_ptr == inside_ptr 7624 && ! (inside_ptr 7625 && TREE_CODE (TREE_TYPE (inside_type)) == ARRAY_TYPE 7626 && TREE_CODE (TREE_TYPE (type)) != ARRAY_TYPE) 7627 && ! ((strcmp (lang_hooks.name, "GNU Java") == 0) 7628 && final_ptr)) 7629 return fold_build1 (code, type, TREE_OPERAND (op0, 0)); 7630 } 7631 7632 /* Handle (T *)&A.B.C for A being of type T and B and C 7633 living at offset zero. This occurs frequently in 7634 C++ upcasting and then accessing the base. */ 7635 if (TREE_CODE (op0) == ADDR_EXPR 7636 && POINTER_TYPE_P (type) 7637 && handled_component_p (TREE_OPERAND (op0, 0))) 7638 { 7639 HOST_WIDE_INT bitsize, bitpos; 7640 tree offset; 7641 enum machine_mode mode; 7642 int unsignedp, volatilep; 7643 tree base = TREE_OPERAND (op0, 0); 7644 base = get_inner_reference (base, &bitsize, &bitpos, &offset, 7645 &mode, &unsignedp, &volatilep, false); 7646 /* If the reference was to a (constant) zero offset, we can use 7647 the address of the base if it has the same base type 7648 as the result type. */ 7649 if (! offset && bitpos == 0 7650 && TYPE_MAIN_VARIANT (TREE_TYPE (type)) 7651 == TYPE_MAIN_VARIANT (TREE_TYPE (base))) 7652 return fold_convert (type, build_fold_addr_expr (base)); 7653 } 7654 7655 if (TREE_CODE (op0) == MODIFY_EXPR 7656 && TREE_CONSTANT (TREE_OPERAND (op0, 1)) 7657 /* Detect assigning a bitfield. */ 7658 && !(TREE_CODE (TREE_OPERAND (op0, 0)) == COMPONENT_REF 7659 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (op0, 0), 1)))) 7660 { 7661 /* Don't leave an assignment inside a conversion 7662 unless assigning a bitfield. */ 7663 tem = fold_build1 (code, type, TREE_OPERAND (op0, 1)); 7664 /* First do the assignment, then return converted constant. */ 7665 tem = build2 (COMPOUND_EXPR, TREE_TYPE (tem), op0, tem); 7666 TREE_NO_WARNING (tem) = 1; 7667 TREE_USED (tem) = 1; 7668 return tem; 7669 } 7670 7671 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer 7672 constants (if x has signed type, the sign bit cannot be set 7673 in c). This folds extension into the BIT_AND_EXPR. */ 7674 if (INTEGRAL_TYPE_P (type) 7675 && TREE_CODE (type) != BOOLEAN_TYPE 7676 && TREE_CODE (op0) == BIT_AND_EXPR 7677 && TREE_CODE (TREE_OPERAND (op0, 1)) == INTEGER_CST) 7678 { 7679 tree and = op0; 7680 tree and0 = TREE_OPERAND (and, 0), and1 = TREE_OPERAND (and, 1); 7681 int change = 0; 7682 7683 if (TYPE_UNSIGNED (TREE_TYPE (and)) 7684 || (TYPE_PRECISION (type) 7685 <= TYPE_PRECISION (TREE_TYPE (and)))) 7686 change = 1; 7687 else if (TYPE_PRECISION (TREE_TYPE (and1)) 7688 <= HOST_BITS_PER_WIDE_INT 7689 && host_integerp (and1, 1)) 7690 { 7691 unsigned HOST_WIDE_INT cst; 7692 7693 cst = tree_low_cst (and1, 1); 7694 cst &= (HOST_WIDE_INT) -1 7695 << (TYPE_PRECISION (TREE_TYPE (and1)) - 1); 7696 change = (cst == 0); 7697#ifdef LOAD_EXTEND_OP 7698 if (change 7699 && !flag_syntax_only 7700 && (LOAD_EXTEND_OP (TYPE_MODE (TREE_TYPE (and0))) 7701 == ZERO_EXTEND)) 7702 { 7703 tree uns = lang_hooks.types.unsigned_type (TREE_TYPE (and0)); 7704 and0 = fold_convert (uns, and0); 7705 and1 = fold_convert (uns, and1); 7706 } 7707#endif 7708 } 7709 if (change) 7710 { 7711 tem = build_int_cst_wide (type, TREE_INT_CST_LOW (and1), 7712 TREE_INT_CST_HIGH (and1)); 7713 tem = force_fit_type (tem, 0, TREE_OVERFLOW (and1), 7714 TREE_CONSTANT_OVERFLOW (and1)); 7715 return fold_build2 (BIT_AND_EXPR, type, 7716 fold_convert (type, and0), tem); 7717 } 7718 } 7719 7720 /* Convert (T1)((T2)X op Y) into (T1)X op Y, for pointer types T1 and 7721 T2 being pointers to types of the same size. */ 7722 if (POINTER_TYPE_P (type) 7723 && BINARY_CLASS_P (arg0) 7724 && TREE_CODE (TREE_OPERAND (arg0, 0)) == NOP_EXPR 7725 && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))) 7726 { 7727 tree arg00 = TREE_OPERAND (arg0, 0); 7728 tree t0 = type; 7729 tree t1 = TREE_TYPE (arg00); 7730 tree tt0 = TREE_TYPE (t0); 7731 tree tt1 = TREE_TYPE (t1); 7732 tree s0 = TYPE_SIZE (tt0); 7733 tree s1 = TYPE_SIZE (tt1); 7734 7735 if (s0 && s1 && operand_equal_p (s0, s1, OEP_ONLY_CONST)) 7736 return build2 (TREE_CODE (arg0), t0, fold_convert (t0, arg00), 7737 TREE_OPERAND (arg0, 1)); 7738 } 7739 7740 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types 7741 of the same precision, and X is a integer type not narrower than 7742 types T1 or T2, i.e. the cast (T2)X isn't an extension. */ 7743 if (INTEGRAL_TYPE_P (type) 7744 && TREE_CODE (op0) == BIT_NOT_EXPR 7745 && INTEGRAL_TYPE_P (TREE_TYPE (op0)) 7746 && (TREE_CODE (TREE_OPERAND (op0, 0)) == NOP_EXPR 7747 || TREE_CODE (TREE_OPERAND (op0, 0)) == CONVERT_EXPR) 7748 && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (op0))) 7749 { 7750 tem = TREE_OPERAND (TREE_OPERAND (op0, 0), 0); 7751 if (INTEGRAL_TYPE_P (TREE_TYPE (tem)) 7752 && TYPE_PRECISION (type) <= TYPE_PRECISION (TREE_TYPE (tem))) 7753 return fold_build1 (BIT_NOT_EXPR, type, fold_convert (type, tem)); 7754 } 7755 7756 tem = fold_convert_const (code, type, op0); 7757 return tem ? tem : NULL_TREE; 7758 7759 case VIEW_CONVERT_EXPR: 7760 if (TREE_CODE (op0) == VIEW_CONVERT_EXPR) 7761 return fold_build1 (VIEW_CONVERT_EXPR, type, TREE_OPERAND (op0, 0)); 7762 return fold_view_convert_expr (type, op0); 7763 7764 case NEGATE_EXPR: 7765 tem = fold_negate_expr (arg0); 7766 if (tem) 7767 return fold_convert (type, tem); 7768 return NULL_TREE; 7769 7770 case ABS_EXPR: 7771 if (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST) 7772 return fold_abs_const (arg0, type); 7773 else if (TREE_CODE (arg0) == NEGATE_EXPR) 7774 return fold_build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0)); 7775 /* Convert fabs((double)float) into (double)fabsf(float). */ 7776 else if (TREE_CODE (arg0) == NOP_EXPR 7777 && TREE_CODE (type) == REAL_TYPE) 7778 { 7779 tree targ0 = strip_float_extensions (arg0); 7780 if (targ0 != arg0) 7781 return fold_convert (type, fold_build1 (ABS_EXPR, 7782 TREE_TYPE (targ0), 7783 targ0)); 7784 } 7785 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */ 7786 else if (TREE_CODE (arg0) == ABS_EXPR) 7787 return arg0; 7788 else if (tree_expr_nonnegative_p (arg0)) 7789 return arg0; 7790 7791 /* Strip sign ops from argument. */ 7792 if (TREE_CODE (type) == REAL_TYPE) 7793 { 7794 tem = fold_strip_sign_ops (arg0); 7795 if (tem) 7796 return fold_build1 (ABS_EXPR, type, fold_convert (type, tem)); 7797 } 7798 return NULL_TREE; 7799 7800 case CONJ_EXPR: 7801 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE) 7802 return fold_convert (type, arg0); 7803 if (TREE_CODE (arg0) == COMPLEX_EXPR) 7804 { 7805 tree itype = TREE_TYPE (type); 7806 tree rpart = fold_convert (itype, TREE_OPERAND (arg0, 0)); 7807 tree ipart = fold_convert (itype, TREE_OPERAND (arg0, 1)); 7808 return fold_build2 (COMPLEX_EXPR, type, rpart, negate_expr (ipart)); 7809 } 7810 if (TREE_CODE (arg0) == COMPLEX_CST) 7811 { 7812 tree itype = TREE_TYPE (type); 7813 tree rpart = fold_convert (itype, TREE_REALPART (arg0)); 7814 tree ipart = fold_convert (itype, TREE_IMAGPART (arg0)); 7815 return build_complex (type, rpart, negate_expr (ipart)); 7816 } 7817 if (TREE_CODE (arg0) == CONJ_EXPR) 7818 return fold_convert (type, TREE_OPERAND (arg0, 0)); 7819 return NULL_TREE; 7820 7821 case BIT_NOT_EXPR: 7822 if (TREE_CODE (arg0) == INTEGER_CST) 7823 return fold_not_const (arg0, type); 7824 else if (TREE_CODE (arg0) == BIT_NOT_EXPR) 7825 return TREE_OPERAND (arg0, 0); 7826 /* Convert ~ (-A) to A - 1. */ 7827 else if (INTEGRAL_TYPE_P (type) && TREE_CODE (arg0) == NEGATE_EXPR) 7828 return fold_build2 (MINUS_EXPR, type, TREE_OPERAND (arg0, 0), 7829 build_int_cst (type, 1)); 7830 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */ 7831 else if (INTEGRAL_TYPE_P (type) 7832 && ((TREE_CODE (arg0) == MINUS_EXPR 7833 && integer_onep (TREE_OPERAND (arg0, 1))) 7834 || (TREE_CODE (arg0) == PLUS_EXPR 7835 && integer_all_onesp (TREE_OPERAND (arg0, 1))))) 7836 return fold_build1 (NEGATE_EXPR, type, TREE_OPERAND (arg0, 0)); 7837 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */ 7838 else if (TREE_CODE (arg0) == BIT_XOR_EXPR 7839 && (tem = fold_unary (BIT_NOT_EXPR, type, 7840 fold_convert (type, 7841 TREE_OPERAND (arg0, 0))))) 7842 return fold_build2 (BIT_XOR_EXPR, type, tem, 7843 fold_convert (type, TREE_OPERAND (arg0, 1))); 7844 else if (TREE_CODE (arg0) == BIT_XOR_EXPR 7845 && (tem = fold_unary (BIT_NOT_EXPR, type, 7846 fold_convert (type, 7847 TREE_OPERAND (arg0, 1))))) 7848 return fold_build2 (BIT_XOR_EXPR, type, 7849 fold_convert (type, TREE_OPERAND (arg0, 0)), tem); 7850 7851 return NULL_TREE; 7852 7853 case TRUTH_NOT_EXPR: 7854 /* The argument to invert_truthvalue must have Boolean type. */ 7855 if (TREE_CODE (TREE_TYPE (arg0)) != BOOLEAN_TYPE) 7856 arg0 = fold_convert (boolean_type_node, arg0); 7857 7858 /* Note that the operand of this must be an int 7859 and its values must be 0 or 1. 7860 ("true" is a fixed value perhaps depending on the language, 7861 but we don't handle values other than 1 correctly yet.) */ 7862 tem = fold_truth_not_expr (arg0); 7863 if (!tem) 7864 return NULL_TREE; 7865 return fold_convert (type, tem); 7866 7867 case REALPART_EXPR: 7868 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE) 7869 return fold_convert (type, arg0); 7870 if (TREE_CODE (arg0) == COMPLEX_EXPR) 7871 return omit_one_operand (type, TREE_OPERAND (arg0, 0), 7872 TREE_OPERAND (arg0, 1)); 7873 if (TREE_CODE (arg0) == COMPLEX_CST) 7874 return fold_convert (type, TREE_REALPART (arg0)); 7875 if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) 7876 { 7877 tree itype = TREE_TYPE (TREE_TYPE (arg0)); 7878 tem = fold_build2 (TREE_CODE (arg0), itype, 7879 fold_build1 (REALPART_EXPR, itype, 7880 TREE_OPERAND (arg0, 0)), 7881 fold_build1 (REALPART_EXPR, itype, 7882 TREE_OPERAND (arg0, 1))); 7883 return fold_convert (type, tem); 7884 } 7885 if (TREE_CODE (arg0) == CONJ_EXPR) 7886 { 7887 tree itype = TREE_TYPE (TREE_TYPE (arg0)); 7888 tem = fold_build1 (REALPART_EXPR, itype, TREE_OPERAND (arg0, 0)); 7889 return fold_convert (type, tem); 7890 } 7891 return NULL_TREE; 7892 7893 case IMAGPART_EXPR: 7894 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE) 7895 return fold_convert (type, integer_zero_node); 7896 if (TREE_CODE (arg0) == COMPLEX_EXPR) 7897 return omit_one_operand (type, TREE_OPERAND (arg0, 1), 7898 TREE_OPERAND (arg0, 0)); 7899 if (TREE_CODE (arg0) == COMPLEX_CST) 7900 return fold_convert (type, TREE_IMAGPART (arg0)); 7901 if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) 7902 { 7903 tree itype = TREE_TYPE (TREE_TYPE (arg0)); 7904 tem = fold_build2 (TREE_CODE (arg0), itype, 7905 fold_build1 (IMAGPART_EXPR, itype, 7906 TREE_OPERAND (arg0, 0)), 7907 fold_build1 (IMAGPART_EXPR, itype, 7908 TREE_OPERAND (arg0, 1))); 7909 return fold_convert (type, tem); 7910 } 7911 if (TREE_CODE (arg0) == CONJ_EXPR) 7912 { 7913 tree itype = TREE_TYPE (TREE_TYPE (arg0)); 7914 tem = fold_build1 (IMAGPART_EXPR, itype, TREE_OPERAND (arg0, 0)); 7915 return fold_convert (type, negate_expr (tem)); 7916 } 7917 return NULL_TREE; 7918 7919 default: 7920 return NULL_TREE; 7921 } /* switch (code) */ 7922} 7923 7924/* Fold a binary expression of code CODE and type TYPE with operands 7925 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination. 7926 Return the folded expression if folding is successful. Otherwise, 7927 return NULL_TREE. */ 7928 7929static tree 7930fold_minmax (enum tree_code code, tree type, tree op0, tree op1) 7931{ 7932 enum tree_code compl_code; 7933 7934 if (code == MIN_EXPR) 7935 compl_code = MAX_EXPR; 7936 else if (code == MAX_EXPR) 7937 compl_code = MIN_EXPR; 7938 else 7939 gcc_unreachable (); 7940 7941 /* MIN (MAX (a, b), b) == b. */ 7942 if (TREE_CODE (op0) == compl_code 7943 && operand_equal_p (TREE_OPERAND (op0, 1), op1, 0)) 7944 return omit_one_operand (type, op1, TREE_OPERAND (op0, 0)); 7945 7946 /* MIN (MAX (b, a), b) == b. */ 7947 if (TREE_CODE (op0) == compl_code 7948 && operand_equal_p (TREE_OPERAND (op0, 0), op1, 0) 7949 && reorder_operands_p (TREE_OPERAND (op0, 1), op1)) 7950 return omit_one_operand (type, op1, TREE_OPERAND (op0, 1)); 7951 7952 /* MIN (a, MAX (a, b)) == a. */ 7953 if (TREE_CODE (op1) == compl_code 7954 && operand_equal_p (op0, TREE_OPERAND (op1, 0), 0) 7955 && reorder_operands_p (op0, TREE_OPERAND (op1, 1))) 7956 return omit_one_operand (type, op0, TREE_OPERAND (op1, 1)); 7957 7958 /* MIN (a, MAX (b, a)) == a. */ 7959 if (TREE_CODE (op1) == compl_code 7960 && operand_equal_p (op0, TREE_OPERAND (op1, 1), 0) 7961 && reorder_operands_p (op0, TREE_OPERAND (op1, 0))) 7962 return omit_one_operand (type, op0, TREE_OPERAND (op1, 0)); 7963 7964 return NULL_TREE; 7965} 7966 7967/* Subroutine of fold_binary. This routine performs all of the 7968 transformations that are common to the equality/inequality 7969 operators (EQ_EXPR and NE_EXPR) and the ordering operators 7970 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than 7971 fold_binary should call fold_binary. Fold a comparison with 7972 tree code CODE and type TYPE with operands OP0 and OP1. Return 7973 the folded comparison or NULL_TREE. */ 7974 7975static tree 7976fold_comparison (enum tree_code code, tree type, tree op0, tree op1) 7977{ 7978 tree arg0, arg1, tem; 7979 7980 arg0 = op0; 7981 arg1 = op1; 7982 7983 STRIP_SIGN_NOPS (arg0); 7984 STRIP_SIGN_NOPS (arg1); 7985 7986 tem = fold_relational_const (code, type, arg0, arg1); 7987 if (tem != NULL_TREE) 7988 return tem; 7989 7990 /* If one arg is a real or integer constant, put it last. */ 7991 if (tree_swap_operands_p (arg0, arg1, true)) 7992 return fold_build2 (swap_tree_comparison (code), type, op1, op0); 7993 7994 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */ 7995 if ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) 7996 && (TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST 7997 && !TREE_OVERFLOW (TREE_OPERAND (arg0, 1)) 7998 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))) 7999 && (TREE_CODE (arg1) == INTEGER_CST 8000 && !TREE_OVERFLOW (arg1))) 8001 { 8002 tree const1 = TREE_OPERAND (arg0, 1); 8003 tree const2 = arg1; 8004 tree variable = TREE_OPERAND (arg0, 0); 8005 tree lhs; 8006 int lhs_add; 8007 lhs_add = TREE_CODE (arg0) != PLUS_EXPR; 8008 8009 lhs = fold_build2 (lhs_add ? PLUS_EXPR : MINUS_EXPR, 8010 TREE_TYPE (arg1), const2, const1); 8011 if (TREE_CODE (lhs) == TREE_CODE (arg1) 8012 && (TREE_CODE (lhs) != INTEGER_CST 8013 || !TREE_OVERFLOW (lhs))) 8014 { 8015 fold_overflow_warning (("assuming signed overflow does not occur " 8016 "when changing X +- C1 cmp C2 to " 8017 "X cmp C1 +- C2"), 8018 WARN_STRICT_OVERFLOW_COMPARISON); 8019 return fold_build2 (code, type, variable, lhs); 8020 } 8021 } 8022 8023 /* If this is a comparison of two exprs that look like an ARRAY_REF of the 8024 same object, then we can fold this to a comparison of the two offsets in 8025 signed size type. This is possible because pointer arithmetic is 8026 restricted to retain within an object and overflow on pointer differences 8027 is undefined as of 6.5.6/8 and /9 with respect to the signed ptrdiff_t. 8028 8029 We check flag_wrapv directly because pointers types are unsigned, 8030 and therefore TYPE_OVERFLOW_WRAPS returns true for them. That is 8031 normally what we want to avoid certain odd overflow cases, but 8032 not here. */ 8033 if (POINTER_TYPE_P (TREE_TYPE (arg0)) 8034 && !flag_wrapv 8035 && !TYPE_OVERFLOW_TRAPS (TREE_TYPE (arg0))) 8036 { 8037 tree base0, offset0, base1, offset1; 8038 8039 if (extract_array_ref (arg0, &base0, &offset0) 8040 && extract_array_ref (arg1, &base1, &offset1) 8041 && operand_equal_p (base0, base1, 0)) 8042 { 8043 tree signed_size_type_node; 8044 signed_size_type_node = signed_type_for (size_type_node); 8045 8046 /* By converting to signed size type we cover middle-end pointer 8047 arithmetic which operates on unsigned pointer types of size 8048 type size and ARRAY_REF offsets which are properly sign or 8049 zero extended from their type in case it is narrower than 8050 size type. */ 8051 if (offset0 == NULL_TREE) 8052 offset0 = build_int_cst (signed_size_type_node, 0); 8053 else 8054 offset0 = fold_convert (signed_size_type_node, offset0); 8055 if (offset1 == NULL_TREE) 8056 offset1 = build_int_cst (signed_size_type_node, 0); 8057 else 8058 offset1 = fold_convert (signed_size_type_node, offset1); 8059 8060 return fold_build2 (code, type, offset0, offset1); 8061 } 8062 } 8063 8064 if (FLOAT_TYPE_P (TREE_TYPE (arg0))) 8065 { 8066 tree targ0 = strip_float_extensions (arg0); 8067 tree targ1 = strip_float_extensions (arg1); 8068 tree newtype = TREE_TYPE (targ0); 8069 8070 if (TYPE_PRECISION (TREE_TYPE (targ1)) > TYPE_PRECISION (newtype)) 8071 newtype = TREE_TYPE (targ1); 8072 8073 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */ 8074 if (TYPE_PRECISION (newtype) < TYPE_PRECISION (TREE_TYPE (arg0))) 8075 return fold_build2 (code, type, fold_convert (newtype, targ0), 8076 fold_convert (newtype, targ1)); 8077 8078 /* (-a) CMP (-b) -> b CMP a */ 8079 if (TREE_CODE (arg0) == NEGATE_EXPR 8080 && TREE_CODE (arg1) == NEGATE_EXPR) 8081 return fold_build2 (code, type, TREE_OPERAND (arg1, 0), 8082 TREE_OPERAND (arg0, 0)); 8083 8084 if (TREE_CODE (arg1) == REAL_CST) 8085 { 8086 REAL_VALUE_TYPE cst; 8087 cst = TREE_REAL_CST (arg1); 8088 8089 /* (-a) CMP CST -> a swap(CMP) (-CST) */ 8090 if (TREE_CODE (arg0) == NEGATE_EXPR) 8091 return fold_build2 (swap_tree_comparison (code), type, 8092 TREE_OPERAND (arg0, 0), 8093 build_real (TREE_TYPE (arg1), 8094 REAL_VALUE_NEGATE (cst))); 8095 8096 /* IEEE doesn't distinguish +0 and -0 in comparisons. */ 8097 /* a CMP (-0) -> a CMP 0 */ 8098 if (REAL_VALUE_MINUS_ZERO (cst)) 8099 return fold_build2 (code, type, arg0, 8100 build_real (TREE_TYPE (arg1), dconst0)); 8101 8102 /* x != NaN is always true, other ops are always false. */ 8103 if (REAL_VALUE_ISNAN (cst) 8104 && ! HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg1)))) 8105 { 8106 tem = (code == NE_EXPR) ? integer_one_node : integer_zero_node; 8107 return omit_one_operand (type, tem, arg0); 8108 } 8109 8110 /* Fold comparisons against infinity. */ 8111 if (REAL_VALUE_ISINF (cst)) 8112 { 8113 tem = fold_inf_compare (code, type, arg0, arg1); 8114 if (tem != NULL_TREE) 8115 return tem; 8116 } 8117 } 8118 8119 /* If this is a comparison of a real constant with a PLUS_EXPR 8120 or a MINUS_EXPR of a real constant, we can convert it into a 8121 comparison with a revised real constant as long as no overflow 8122 occurs when unsafe_math_optimizations are enabled. */ 8123 if (flag_unsafe_math_optimizations 8124 && TREE_CODE (arg1) == REAL_CST 8125 && (TREE_CODE (arg0) == PLUS_EXPR 8126 || TREE_CODE (arg0) == MINUS_EXPR) 8127 && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST 8128 && 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR 8129 ? MINUS_EXPR : PLUS_EXPR, 8130 arg1, TREE_OPERAND (arg0, 1), 0)) 8131 && ! TREE_CONSTANT_OVERFLOW (tem)) 8132 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), tem); 8133 8134 /* Likewise, we can simplify a comparison of a real constant with 8135 a MINUS_EXPR whose first operand is also a real constant, i.e. 8136 (c1 - x) < c2 becomes x > c1-c2. */ 8137 if (flag_unsafe_math_optimizations 8138 && TREE_CODE (arg1) == REAL_CST 8139 && TREE_CODE (arg0) == MINUS_EXPR 8140 && TREE_CODE (TREE_OPERAND (arg0, 0)) == REAL_CST 8141 && 0 != (tem = const_binop (MINUS_EXPR, TREE_OPERAND (arg0, 0), 8142 arg1, 0)) 8143 && ! TREE_CONSTANT_OVERFLOW (tem)) 8144 return fold_build2 (swap_tree_comparison (code), type, 8145 TREE_OPERAND (arg0, 1), tem); 8146 8147 /* Fold comparisons against built-in math functions. */ 8148 if (TREE_CODE (arg1) == REAL_CST 8149 && flag_unsafe_math_optimizations 8150 && ! flag_errno_math) 8151 { 8152 enum built_in_function fcode = builtin_mathfn_code (arg0); 8153 8154 if (fcode != END_BUILTINS) 8155 { 8156 tem = fold_mathfn_compare (fcode, code, type, arg0, arg1); 8157 if (tem != NULL_TREE) 8158 return tem; 8159 } 8160 } 8161 } 8162 8163 /* Convert foo++ == CONST into ++foo == CONST + INCR. */ 8164 if (TREE_CONSTANT (arg1) 8165 && (TREE_CODE (arg0) == POSTINCREMENT_EXPR 8166 || TREE_CODE (arg0) == POSTDECREMENT_EXPR) 8167 /* This optimization is invalid for ordered comparisons 8168 if CONST+INCR overflows or if foo+incr might overflow. 8169 This optimization is invalid for floating point due to rounding. 8170 For pointer types we assume overflow doesn't happen. */ 8171 && (POINTER_TYPE_P (TREE_TYPE (arg0)) 8172 || (INTEGRAL_TYPE_P (TREE_TYPE (arg0)) 8173 && (code == EQ_EXPR || code == NE_EXPR)))) 8174 { 8175 tree varop, newconst; 8176 8177 if (TREE_CODE (arg0) == POSTINCREMENT_EXPR) 8178 { 8179 newconst = fold_build2 (PLUS_EXPR, TREE_TYPE (arg0), 8180 arg1, TREE_OPERAND (arg0, 1)); 8181 varop = build2 (PREINCREMENT_EXPR, TREE_TYPE (arg0), 8182 TREE_OPERAND (arg0, 0), 8183 TREE_OPERAND (arg0, 1)); 8184 } 8185 else 8186 { 8187 newconst = fold_build2 (MINUS_EXPR, TREE_TYPE (arg0), 8188 arg1, TREE_OPERAND (arg0, 1)); 8189 varop = build2 (PREDECREMENT_EXPR, TREE_TYPE (arg0), 8190 TREE_OPERAND (arg0, 0), 8191 TREE_OPERAND (arg0, 1)); 8192 } 8193 8194 8195 /* If VAROP is a reference to a bitfield, we must mask 8196 the constant by the width of the field. */ 8197 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF 8198 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (varop, 0), 1)) 8199 && host_integerp (DECL_SIZE (TREE_OPERAND 8200 (TREE_OPERAND (varop, 0), 1)), 1)) 8201 { 8202 tree fielddecl = TREE_OPERAND (TREE_OPERAND (varop, 0), 1); 8203 HOST_WIDE_INT size = tree_low_cst (DECL_SIZE (fielddecl), 1); 8204 tree folded_compare, shift; 8205 8206 /* First check whether the comparison would come out 8207 always the same. If we don't do that we would 8208 change the meaning with the masking. */ 8209 folded_compare = fold_build2 (code, type, 8210 TREE_OPERAND (varop, 0), arg1); 8211 if (TREE_CODE (folded_compare) == INTEGER_CST) 8212 return omit_one_operand (type, folded_compare, varop); 8213 8214 shift = build_int_cst (NULL_TREE, 8215 TYPE_PRECISION (TREE_TYPE (varop)) - size); 8216 shift = fold_convert (TREE_TYPE (varop), shift); 8217 newconst = fold_build2 (LSHIFT_EXPR, TREE_TYPE (varop), 8218 newconst, shift); 8219 newconst = fold_build2 (RSHIFT_EXPR, TREE_TYPE (varop), 8220 newconst, shift); 8221 } 8222 8223 return fold_build2 (code, type, varop, newconst); 8224 } 8225 8226 if (TREE_CODE (TREE_TYPE (arg0)) == INTEGER_TYPE 8227 && (TREE_CODE (arg0) == NOP_EXPR 8228 || TREE_CODE (arg0) == CONVERT_EXPR)) 8229 { 8230 /* If we are widening one operand of an integer comparison, 8231 see if the other operand is similarly being widened. Perhaps we 8232 can do the comparison in the narrower type. */ 8233 tem = fold_widened_comparison (code, type, arg0, arg1); 8234 if (tem) 8235 return tem; 8236 8237 /* Or if we are changing signedness. */ 8238 tem = fold_sign_changed_comparison (code, type, arg0, arg1); 8239 if (tem) 8240 return tem; 8241 } 8242 8243 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a 8244 constant, we can simplify it. */ 8245 if (TREE_CODE (arg1) == INTEGER_CST 8246 && (TREE_CODE (arg0) == MIN_EXPR 8247 || TREE_CODE (arg0) == MAX_EXPR) 8248 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) 8249 { 8250 tem = optimize_minmax_comparison (code, type, op0, op1); 8251 if (tem) 8252 return tem; 8253 } 8254 8255 /* Simplify comparison of something with itself. (For IEEE 8256 floating-point, we can only do some of these simplifications.) */ 8257 if (operand_equal_p (arg0, arg1, 0)) 8258 { 8259 switch (code) 8260 { 8261 case EQ_EXPR: 8262 if (! FLOAT_TYPE_P (TREE_TYPE (arg0)) 8263 || ! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))) 8264 return constant_boolean_node (1, type); 8265 break; 8266 8267 case GE_EXPR: 8268 case LE_EXPR: 8269 if (! FLOAT_TYPE_P (TREE_TYPE (arg0)) 8270 || ! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))) 8271 return constant_boolean_node (1, type); 8272 return fold_build2 (EQ_EXPR, type, arg0, arg1); 8273 8274 case NE_EXPR: 8275 /* For NE, we can only do this simplification if integer 8276 or we don't honor IEEE floating point NaNs. */ 8277 if (FLOAT_TYPE_P (TREE_TYPE (arg0)) 8278 && HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))) 8279 break; 8280 /* ... fall through ... */ 8281 case GT_EXPR: 8282 case LT_EXPR: 8283 return constant_boolean_node (0, type); 8284 default: 8285 gcc_unreachable (); 8286 } 8287 } 8288 8289 /* If we are comparing an expression that just has comparisons 8290 of two integer values, arithmetic expressions of those comparisons, 8291 and constants, we can simplify it. There are only three cases 8292 to check: the two values can either be equal, the first can be 8293 greater, or the second can be greater. Fold the expression for 8294 those three values. Since each value must be 0 or 1, we have 8295 eight possibilities, each of which corresponds to the constant 0 8296 or 1 or one of the six possible comparisons. 8297 8298 This handles common cases like (a > b) == 0 but also handles 8299 expressions like ((x > y) - (y > x)) > 0, which supposedly 8300 occur in macroized code. */ 8301 8302 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST) 8303 { 8304 tree cval1 = 0, cval2 = 0; 8305 int save_p = 0; 8306 8307 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p) 8308 /* Don't handle degenerate cases here; they should already 8309 have been handled anyway. */ 8310 && cval1 != 0 && cval2 != 0 8311 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2)) 8312 && TREE_TYPE (cval1) == TREE_TYPE (cval2) 8313 && INTEGRAL_TYPE_P (TREE_TYPE (cval1)) 8314 && TYPE_MAX_VALUE (TREE_TYPE (cval1)) 8315 && TYPE_MAX_VALUE (TREE_TYPE (cval2)) 8316 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)), 8317 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0)) 8318 { 8319 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1)); 8320 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1)); 8321 8322 /* We can't just pass T to eval_subst in case cval1 or cval2 8323 was the same as ARG1. */ 8324 8325 tree high_result 8326 = fold_build2 (code, type, 8327 eval_subst (arg0, cval1, maxval, 8328 cval2, minval), 8329 arg1); 8330 tree equal_result 8331 = fold_build2 (code, type, 8332 eval_subst (arg0, cval1, maxval, 8333 cval2, maxval), 8334 arg1); 8335 tree low_result 8336 = fold_build2 (code, type, 8337 eval_subst (arg0, cval1, minval, 8338 cval2, maxval), 8339 arg1); 8340 8341 /* All three of these results should be 0 or 1. Confirm they are. 8342 Then use those values to select the proper code to use. */ 8343 8344 if (TREE_CODE (high_result) == INTEGER_CST 8345 && TREE_CODE (equal_result) == INTEGER_CST 8346 && TREE_CODE (low_result) == INTEGER_CST) 8347 { 8348 /* Make a 3-bit mask with the high-order bit being the 8349 value for `>', the next for '=', and the low for '<'. */ 8350 switch ((integer_onep (high_result) * 4) 8351 + (integer_onep (equal_result) * 2) 8352 + integer_onep (low_result)) 8353 { 8354 case 0: 8355 /* Always false. */ 8356 return omit_one_operand (type, integer_zero_node, arg0); 8357 case 1: 8358 code = LT_EXPR; 8359 break; 8360 case 2: 8361 code = EQ_EXPR; 8362 break; 8363 case 3: 8364 code = LE_EXPR; 8365 break; 8366 case 4: 8367 code = GT_EXPR; 8368 break; 8369 case 5: 8370 code = NE_EXPR; 8371 break; 8372 case 6: 8373 code = GE_EXPR; 8374 break; 8375 case 7: 8376 /* Always true. */ 8377 return omit_one_operand (type, integer_one_node, arg0); 8378 } 8379 8380 if (save_p) 8381 return save_expr (build2 (code, type, cval1, cval2)); 8382 return fold_build2 (code, type, cval1, cval2); 8383 } 8384 } 8385 } 8386 8387 /* Fold a comparison of the address of COMPONENT_REFs with the same 8388 type and component to a comparison of the address of the base 8389 object. In short, &x->a OP &y->a to x OP y and 8390 &x->a OP &y.a to x OP &y */ 8391 if (TREE_CODE (arg0) == ADDR_EXPR 8392 && TREE_CODE (TREE_OPERAND (arg0, 0)) == COMPONENT_REF 8393 && TREE_CODE (arg1) == ADDR_EXPR 8394 && TREE_CODE (TREE_OPERAND (arg1, 0)) == COMPONENT_REF) 8395 { 8396 tree cref0 = TREE_OPERAND (arg0, 0); 8397 tree cref1 = TREE_OPERAND (arg1, 0); 8398 if (TREE_OPERAND (cref0, 1) == TREE_OPERAND (cref1, 1)) 8399 { 8400 tree op0 = TREE_OPERAND (cref0, 0); 8401 tree op1 = TREE_OPERAND (cref1, 0); 8402 return fold_build2 (code, type, 8403 build_fold_addr_expr (op0), 8404 build_fold_addr_expr (op1)); 8405 } 8406 } 8407 8408 /* We can fold X/C1 op C2 where C1 and C2 are integer constants 8409 into a single range test. */ 8410 if ((TREE_CODE (arg0) == TRUNC_DIV_EXPR 8411 || TREE_CODE (arg0) == EXACT_DIV_EXPR) 8412 && TREE_CODE (arg1) == INTEGER_CST 8413 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST 8414 && !integer_zerop (TREE_OPERAND (arg0, 1)) 8415 && !TREE_OVERFLOW (TREE_OPERAND (arg0, 1)) 8416 && !TREE_OVERFLOW (arg1)) 8417 { 8418 tem = fold_div_compare (code, type, arg0, arg1); 8419 if (tem != NULL_TREE) 8420 return tem; 8421 } 8422 8423 return NULL_TREE; 8424} 8425 8426 8427/* Subroutine of fold_binary. Optimize complex multiplications of the 8428 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The 8429 argument EXPR represents the expression "z" of type TYPE. */ 8430 8431static tree 8432fold_mult_zconjz (tree type, tree expr) 8433{ 8434 tree itype = TREE_TYPE (type); 8435 tree rpart, ipart, tem; 8436 8437 if (TREE_CODE (expr) == COMPLEX_EXPR) 8438 { 8439 rpart = TREE_OPERAND (expr, 0); 8440 ipart = TREE_OPERAND (expr, 1); 8441 } 8442 else if (TREE_CODE (expr) == COMPLEX_CST) 8443 { 8444 rpart = TREE_REALPART (expr); 8445 ipart = TREE_IMAGPART (expr); 8446 } 8447 else 8448 { 8449 expr = save_expr (expr); 8450 rpart = fold_build1 (REALPART_EXPR, itype, expr); 8451 ipart = fold_build1 (IMAGPART_EXPR, itype, expr); 8452 } 8453 8454 rpart = save_expr (rpart); 8455 ipart = save_expr (ipart); 8456 tem = fold_build2 (PLUS_EXPR, itype, 8457 fold_build2 (MULT_EXPR, itype, rpart, rpart), 8458 fold_build2 (MULT_EXPR, itype, ipart, ipart)); 8459 return fold_build2 (COMPLEX_EXPR, type, tem, 8460 fold_convert (itype, integer_zero_node)); 8461} 8462 8463 8464/* Fold a binary expression of code CODE and type TYPE with operands 8465 OP0 and OP1. Return the folded expression if folding is 8466 successful. Otherwise, return NULL_TREE. */ 8467 8468tree 8469fold_binary (enum tree_code code, tree type, tree op0, tree op1) 8470{ 8471 enum tree_code_class kind = TREE_CODE_CLASS (code); 8472 tree arg0, arg1, tem; 8473 tree t1 = NULL_TREE; 8474 bool strict_overflow_p; 8475 8476 gcc_assert (IS_EXPR_CODE_CLASS (kind) 8477 && TREE_CODE_LENGTH (code) == 2 8478 && op0 != NULL_TREE 8479 && op1 != NULL_TREE); 8480 8481 arg0 = op0; 8482 arg1 = op1; 8483 8484 /* Strip any conversions that don't change the mode. This is 8485 safe for every expression, except for a comparison expression 8486 because its signedness is derived from its operands. So, in 8487 the latter case, only strip conversions that don't change the 8488 signedness. 8489 8490 Note that this is done as an internal manipulation within the 8491 constant folder, in order to find the simplest representation 8492 of the arguments so that their form can be studied. In any 8493 cases, the appropriate type conversions should be put back in 8494 the tree that will get out of the constant folder. */ 8495 8496 if (kind == tcc_comparison) 8497 { 8498 STRIP_SIGN_NOPS (arg0); 8499 STRIP_SIGN_NOPS (arg1); 8500 } 8501 else 8502 { 8503 STRIP_NOPS (arg0); 8504 STRIP_NOPS (arg1); 8505 } 8506 8507 /* Note that TREE_CONSTANT isn't enough: static var addresses are 8508 constant but we can't do arithmetic on them. */ 8509 if ((TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) 8510 || (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST) 8511 || (TREE_CODE (arg0) == COMPLEX_CST && TREE_CODE (arg1) == COMPLEX_CST) 8512 || (TREE_CODE (arg0) == VECTOR_CST && TREE_CODE (arg1) == VECTOR_CST)) 8513 { 8514 if (kind == tcc_binary) 8515 tem = const_binop (code, arg0, arg1, 0); 8516 else if (kind == tcc_comparison) 8517 tem = fold_relational_const (code, type, arg0, arg1); 8518 else 8519 tem = NULL_TREE; 8520 8521 if (tem != NULL_TREE) 8522 { 8523 if (TREE_TYPE (tem) != type) 8524 tem = fold_convert (type, tem); 8525 return tem; 8526 } 8527 } 8528 8529 /* If this is a commutative operation, and ARG0 is a constant, move it 8530 to ARG1 to reduce the number of tests below. */ 8531 if (commutative_tree_code (code) 8532 && tree_swap_operands_p (arg0, arg1, true)) 8533 return fold_build2 (code, type, op1, op0); 8534 8535 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand. 8536 8537 First check for cases where an arithmetic operation is applied to a 8538 compound, conditional, or comparison operation. Push the arithmetic 8539 operation inside the compound or conditional to see if any folding 8540 can then be done. Convert comparison to conditional for this purpose. 8541 The also optimizes non-constant cases that used to be done in 8542 expand_expr. 8543 8544 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR, 8545 one of the operands is a comparison and the other is a comparison, a 8546 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the 8547 code below would make the expression more complex. Change it to a 8548 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to 8549 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */ 8550 8551 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR 8552 || code == EQ_EXPR || code == NE_EXPR) 8553 && ((truth_value_p (TREE_CODE (arg0)) 8554 && (truth_value_p (TREE_CODE (arg1)) 8555 || (TREE_CODE (arg1) == BIT_AND_EXPR 8556 && integer_onep (TREE_OPERAND (arg1, 1))))) 8557 || (truth_value_p (TREE_CODE (arg1)) 8558 && (truth_value_p (TREE_CODE (arg0)) 8559 || (TREE_CODE (arg0) == BIT_AND_EXPR 8560 && integer_onep (TREE_OPERAND (arg0, 1))))))) 8561 { 8562 tem = fold_build2 (code == BIT_AND_EXPR ? TRUTH_AND_EXPR 8563 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR 8564 : TRUTH_XOR_EXPR, 8565 boolean_type_node, 8566 fold_convert (boolean_type_node, arg0), 8567 fold_convert (boolean_type_node, arg1)); 8568 8569 if (code == EQ_EXPR) 8570 tem = invert_truthvalue (tem); 8571 8572 return fold_convert (type, tem); 8573 } 8574 8575 if (TREE_CODE_CLASS (code) == tcc_binary 8576 || TREE_CODE_CLASS (code) == tcc_comparison) 8577 { 8578 if (TREE_CODE (arg0) == COMPOUND_EXPR) 8579 return build2 (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), 8580 fold_build2 (code, type, 8581 TREE_OPERAND (arg0, 1), op1)); 8582 if (TREE_CODE (arg1) == COMPOUND_EXPR 8583 && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0))) 8584 return build2 (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0), 8585 fold_build2 (code, type, 8586 op0, TREE_OPERAND (arg1, 1))); 8587 8588 if (TREE_CODE (arg0) == COND_EXPR || COMPARISON_CLASS_P (arg0)) 8589 { 8590 tem = fold_binary_op_with_conditional_arg (code, type, op0, op1, 8591 arg0, arg1, 8592 /*cond_first_p=*/1); 8593 if (tem != NULL_TREE) 8594 return tem; 8595 } 8596 8597 if (TREE_CODE (arg1) == COND_EXPR || COMPARISON_CLASS_P (arg1)) 8598 { 8599 tem = fold_binary_op_with_conditional_arg (code, type, op0, op1, 8600 arg1, arg0, 8601 /*cond_first_p=*/0); 8602 if (tem != NULL_TREE) 8603 return tem; 8604 } 8605 } 8606 8607 switch (code) 8608 { 8609 case PLUS_EXPR: 8610 /* A + (-B) -> A - B */ 8611 if (TREE_CODE (arg1) == NEGATE_EXPR) 8612 return fold_build2 (MINUS_EXPR, type, 8613 fold_convert (type, arg0), 8614 fold_convert (type, TREE_OPERAND (arg1, 0))); 8615 /* (-A) + B -> B - A */ 8616 if (TREE_CODE (arg0) == NEGATE_EXPR 8617 && reorder_operands_p (TREE_OPERAND (arg0, 0), arg1)) 8618 return fold_build2 (MINUS_EXPR, type, 8619 fold_convert (type, arg1), 8620 fold_convert (type, TREE_OPERAND (arg0, 0))); 8621 /* Convert ~A + 1 to -A. */ 8622 if (INTEGRAL_TYPE_P (type) 8623 && TREE_CODE (arg0) == BIT_NOT_EXPR 8624 && integer_onep (arg1)) 8625 return fold_build1 (NEGATE_EXPR, type, TREE_OPERAND (arg0, 0)); 8626 8627 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the 8628 same or one. */ 8629 if ((TREE_CODE (arg0) == MULT_EXPR 8630 || TREE_CODE (arg1) == MULT_EXPR) 8631 && (!FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)) 8632 { 8633 tree tem = fold_plusminus_mult_expr (code, type, arg0, arg1); 8634 if (tem) 8635 return tem; 8636 } 8637 8638 if (! FLOAT_TYPE_P (type)) 8639 { 8640 if (integer_zerop (arg1)) 8641 return non_lvalue (fold_convert (type, arg0)); 8642 8643 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing 8644 with a constant, and the two constants have no bits in common, 8645 we should treat this as a BIT_IOR_EXPR since this may produce more 8646 simplifications. */ 8647 if (TREE_CODE (arg0) == BIT_AND_EXPR 8648 && TREE_CODE (arg1) == BIT_AND_EXPR 8649 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST 8650 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST 8651 && integer_zerop (const_binop (BIT_AND_EXPR, 8652 TREE_OPERAND (arg0, 1), 8653 TREE_OPERAND (arg1, 1), 0))) 8654 { 8655 code = BIT_IOR_EXPR; 8656 goto bit_ior; 8657 } 8658 8659 /* Reassociate (plus (plus (mult) (foo)) (mult)) as 8660 (plus (plus (mult) (mult)) (foo)) so that we can 8661 take advantage of the factoring cases below. */ 8662 if (((TREE_CODE (arg0) == PLUS_EXPR 8663 || TREE_CODE (arg0) == MINUS_EXPR) 8664 && TREE_CODE (arg1) == MULT_EXPR) 8665 || ((TREE_CODE (arg1) == PLUS_EXPR 8666 || TREE_CODE (arg1) == MINUS_EXPR) 8667 && TREE_CODE (arg0) == MULT_EXPR)) 8668 { 8669 tree parg0, parg1, parg, marg; 8670 enum tree_code pcode; 8671 8672 if (TREE_CODE (arg1) == MULT_EXPR) 8673 parg = arg0, marg = arg1; 8674 else 8675 parg = arg1, marg = arg0; 8676 pcode = TREE_CODE (parg); 8677 parg0 = TREE_OPERAND (parg, 0); 8678 parg1 = TREE_OPERAND (parg, 1); 8679 STRIP_NOPS (parg0); 8680 STRIP_NOPS (parg1); 8681 8682 if (TREE_CODE (parg0) == MULT_EXPR 8683 && TREE_CODE (parg1) != MULT_EXPR) 8684 return fold_build2 (pcode, type, 8685 fold_build2 (PLUS_EXPR, type, 8686 fold_convert (type, parg0), 8687 fold_convert (type, marg)), 8688 fold_convert (type, parg1)); 8689 if (TREE_CODE (parg0) != MULT_EXPR 8690 && TREE_CODE (parg1) == MULT_EXPR) 8691 return fold_build2 (PLUS_EXPR, type, 8692 fold_convert (type, parg0), 8693 fold_build2 (pcode, type, 8694 fold_convert (type, marg), 8695 fold_convert (type, 8696 parg1))); 8697 } 8698 8699 /* Try replacing &a[i1] + c * i2 with &a[i1 + i2], if c is step 8700 of the array. Loop optimizer sometimes produce this type of 8701 expressions. */ 8702 if (TREE_CODE (arg0) == ADDR_EXPR) 8703 { 8704 tem = try_move_mult_to_index (PLUS_EXPR, arg0, arg1); 8705 if (tem) 8706 return fold_convert (type, tem); 8707 } 8708 else if (TREE_CODE (arg1) == ADDR_EXPR) 8709 { 8710 tem = try_move_mult_to_index (PLUS_EXPR, arg1, arg0); 8711 if (tem) 8712 return fold_convert (type, tem); 8713 } 8714 } 8715 else 8716 { 8717 /* See if ARG1 is zero and X + ARG1 reduces to X. */ 8718 if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 0)) 8719 return non_lvalue (fold_convert (type, arg0)); 8720 8721 /* Likewise if the operands are reversed. */ 8722 if (fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0)) 8723 return non_lvalue (fold_convert (type, arg1)); 8724 8725 /* Convert X + -C into X - C. */ 8726 if (TREE_CODE (arg1) == REAL_CST 8727 && REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg1))) 8728 { 8729 tem = fold_negate_const (arg1, type); 8730 if (!TREE_OVERFLOW (arg1) || !flag_trapping_math) 8731 return fold_build2 (MINUS_EXPR, type, 8732 fold_convert (type, arg0), 8733 fold_convert (type, tem)); 8734 } 8735 8736 if (flag_unsafe_math_optimizations 8737 && (TREE_CODE (arg0) == RDIV_EXPR || TREE_CODE (arg0) == MULT_EXPR) 8738 && (TREE_CODE (arg1) == RDIV_EXPR || TREE_CODE (arg1) == MULT_EXPR) 8739 && (tem = distribute_real_division (code, type, arg0, arg1))) 8740 return tem; 8741 8742 /* Convert x+x into x*2.0. */ 8743 if (operand_equal_p (arg0, arg1, 0) 8744 && SCALAR_FLOAT_TYPE_P (type)) 8745 return fold_build2 (MULT_EXPR, type, arg0, 8746 build_real (type, dconst2)); 8747 8748 /* Convert a + (b*c + d*e) into (a + b*c) + d*e. */ 8749 if (flag_unsafe_math_optimizations 8750 && TREE_CODE (arg1) == PLUS_EXPR 8751 && TREE_CODE (arg0) != MULT_EXPR) 8752 { 8753 tree tree10 = TREE_OPERAND (arg1, 0); 8754 tree tree11 = TREE_OPERAND (arg1, 1); 8755 if (TREE_CODE (tree11) == MULT_EXPR 8756 && TREE_CODE (tree10) == MULT_EXPR) 8757 { 8758 tree tree0; 8759 tree0 = fold_build2 (PLUS_EXPR, type, arg0, tree10); 8760 return fold_build2 (PLUS_EXPR, type, tree0, tree11); 8761 } 8762 } 8763 /* Convert (b*c + d*e) + a into b*c + (d*e +a). */ 8764 if (flag_unsafe_math_optimizations 8765 && TREE_CODE (arg0) == PLUS_EXPR 8766 && TREE_CODE (arg1) != MULT_EXPR) 8767 { 8768 tree tree00 = TREE_OPERAND (arg0, 0); 8769 tree tree01 = TREE_OPERAND (arg0, 1); 8770 if (TREE_CODE (tree01) == MULT_EXPR 8771 && TREE_CODE (tree00) == MULT_EXPR) 8772 { 8773 tree tree0; 8774 tree0 = fold_build2 (PLUS_EXPR, type, tree01, arg1); 8775 return fold_build2 (PLUS_EXPR, type, tree00, tree0); 8776 } 8777 } 8778 } 8779 8780 bit_rotate: 8781 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A 8782 is a rotate of A by C1 bits. */ 8783 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A 8784 is a rotate of A by B bits. */ 8785 { 8786 enum tree_code code0, code1; 8787 code0 = TREE_CODE (arg0); 8788 code1 = TREE_CODE (arg1); 8789 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR) 8790 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR)) 8791 && operand_equal_p (TREE_OPERAND (arg0, 0), 8792 TREE_OPERAND (arg1, 0), 0) 8793 && TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))) 8794 { 8795 tree tree01, tree11; 8796 enum tree_code code01, code11; 8797 8798 tree01 = TREE_OPERAND (arg0, 1); 8799 tree11 = TREE_OPERAND (arg1, 1); 8800 STRIP_NOPS (tree01); 8801 STRIP_NOPS (tree11); 8802 code01 = TREE_CODE (tree01); 8803 code11 = TREE_CODE (tree11); 8804 if (code01 == INTEGER_CST 8805 && code11 == INTEGER_CST 8806 && TREE_INT_CST_HIGH (tree01) == 0 8807 && TREE_INT_CST_HIGH (tree11) == 0 8808 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11)) 8809 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))))) 8810 return build2 (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0), 8811 code0 == LSHIFT_EXPR ? tree01 : tree11); 8812 else if (code11 == MINUS_EXPR) 8813 { 8814 tree tree110, tree111; 8815 tree110 = TREE_OPERAND (tree11, 0); 8816 tree111 = TREE_OPERAND (tree11, 1); 8817 STRIP_NOPS (tree110); 8818 STRIP_NOPS (tree111); 8819 if (TREE_CODE (tree110) == INTEGER_CST 8820 && 0 == compare_tree_int (tree110, 8821 TYPE_PRECISION 8822 (TREE_TYPE (TREE_OPERAND 8823 (arg0, 0)))) 8824 && operand_equal_p (tree01, tree111, 0)) 8825 return build2 ((code0 == LSHIFT_EXPR 8826 ? LROTATE_EXPR 8827 : RROTATE_EXPR), 8828 type, TREE_OPERAND (arg0, 0), tree01); 8829 } 8830 else if (code01 == MINUS_EXPR) 8831 { 8832 tree tree010, tree011; 8833 tree010 = TREE_OPERAND (tree01, 0); 8834 tree011 = TREE_OPERAND (tree01, 1); 8835 STRIP_NOPS (tree010); 8836 STRIP_NOPS (tree011); 8837 if (TREE_CODE (tree010) == INTEGER_CST 8838 && 0 == compare_tree_int (tree010, 8839 TYPE_PRECISION 8840 (TREE_TYPE (TREE_OPERAND 8841 (arg0, 0)))) 8842 && operand_equal_p (tree11, tree011, 0)) 8843 return build2 ((code0 != LSHIFT_EXPR 8844 ? LROTATE_EXPR 8845 : RROTATE_EXPR), 8846 type, TREE_OPERAND (arg0, 0), tree11); 8847 } 8848 } 8849 } 8850 8851 associate: 8852 /* In most languages, can't associate operations on floats through 8853 parentheses. Rather than remember where the parentheses were, we 8854 don't associate floats at all, unless the user has specified 8855 -funsafe-math-optimizations. */ 8856 8857 if (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations) 8858 { 8859 tree var0, con0, lit0, minus_lit0; 8860 tree var1, con1, lit1, minus_lit1; 8861 bool ok = true; 8862 8863 /* Split both trees into variables, constants, and literals. Then 8864 associate each group together, the constants with literals, 8865 then the result with variables. This increases the chances of 8866 literals being recombined later and of generating relocatable 8867 expressions for the sum of a constant and literal. */ 8868 var0 = split_tree (arg0, code, &con0, &lit0, &minus_lit0, 0); 8869 var1 = split_tree (arg1, code, &con1, &lit1, &minus_lit1, 8870 code == MINUS_EXPR); 8871 8872 /* With undefined overflow we can only associate constants 8873 with one variable. */ 8874 if ((POINTER_TYPE_P (type) 8875 || (INTEGRAL_TYPE_P (type) 8876 && !(TYPE_UNSIGNED (type) || flag_wrapv))) 8877 && var0 && var1) 8878 { 8879 tree tmp0 = var0; 8880 tree tmp1 = var1; 8881 8882 if (TREE_CODE (tmp0) == NEGATE_EXPR) 8883 tmp0 = TREE_OPERAND (tmp0, 0); 8884 if (TREE_CODE (tmp1) == NEGATE_EXPR) 8885 tmp1 = TREE_OPERAND (tmp1, 0); 8886 /* The only case we can still associate with two variables 8887 is if they are the same, modulo negation. */ 8888 if (!operand_equal_p (tmp0, tmp1, 0)) 8889 ok = false; 8890 } 8891 8892 /* Only do something if we found more than two objects. Otherwise, 8893 nothing has changed and we risk infinite recursion. */ 8894 if (ok 8895 && (2 < ((var0 != 0) + (var1 != 0) 8896 + (con0 != 0) + (con1 != 0) 8897 + (lit0 != 0) + (lit1 != 0) 8898 + (minus_lit0 != 0) + (minus_lit1 != 0)))) 8899 { 8900 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */ 8901 if (code == MINUS_EXPR) 8902 code = PLUS_EXPR; 8903 8904 var0 = associate_trees (var0, var1, code, type); 8905 con0 = associate_trees (con0, con1, code, type); 8906 lit0 = associate_trees (lit0, lit1, code, type); 8907 minus_lit0 = associate_trees (minus_lit0, minus_lit1, code, type); 8908 8909 /* Preserve the MINUS_EXPR if the negative part of the literal is 8910 greater than the positive part. Otherwise, the multiplicative 8911 folding code (i.e extract_muldiv) may be fooled in case 8912 unsigned constants are subtracted, like in the following 8913 example: ((X*2 + 4) - 8U)/2. */ 8914 if (minus_lit0 && lit0) 8915 { 8916 if (TREE_CODE (lit0) == INTEGER_CST 8917 && TREE_CODE (minus_lit0) == INTEGER_CST 8918 && tree_int_cst_lt (lit0, minus_lit0)) 8919 { 8920 minus_lit0 = associate_trees (minus_lit0, lit0, 8921 MINUS_EXPR, type); 8922 lit0 = 0; 8923 } 8924 else 8925 { 8926 lit0 = associate_trees (lit0, minus_lit0, 8927 MINUS_EXPR, type); 8928 minus_lit0 = 0; 8929 } 8930 } 8931 if (minus_lit0) 8932 { 8933 if (con0 == 0) 8934 return fold_convert (type, 8935 associate_trees (var0, minus_lit0, 8936 MINUS_EXPR, type)); 8937 else 8938 { 8939 con0 = associate_trees (con0, minus_lit0, 8940 MINUS_EXPR, type); 8941 return fold_convert (type, 8942 associate_trees (var0, con0, 8943 PLUS_EXPR, type)); 8944 } 8945 } 8946 8947 con0 = associate_trees (con0, lit0, code, type); 8948 return fold_convert (type, associate_trees (var0, con0, 8949 code, type)); 8950 } 8951 } 8952 8953 return NULL_TREE; 8954 8955 case MINUS_EXPR: 8956 /* A - (-B) -> A + B */ 8957 if (TREE_CODE (arg1) == NEGATE_EXPR) 8958 return fold_build2 (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)); 8959 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */ 8960 if (TREE_CODE (arg0) == NEGATE_EXPR 8961 && (FLOAT_TYPE_P (type) 8962 || (INTEGRAL_TYPE_P (type) && flag_wrapv && !flag_trapv)) 8963 && negate_expr_p (arg1) 8964 && reorder_operands_p (arg0, arg1)) 8965 return fold_build2 (MINUS_EXPR, type, negate_expr (arg1), 8966 TREE_OPERAND (arg0, 0)); 8967 /* Convert -A - 1 to ~A. */ 8968 if (INTEGRAL_TYPE_P (type) 8969 && TREE_CODE (arg0) == NEGATE_EXPR 8970 && integer_onep (arg1)) 8971 return fold_build1 (BIT_NOT_EXPR, type, 8972 fold_convert (type, TREE_OPERAND (arg0, 0))); 8973 8974 /* Convert -1 - A to ~A. */ 8975 if (INTEGRAL_TYPE_P (type) 8976 && integer_all_onesp (arg0)) 8977 return fold_build1 (BIT_NOT_EXPR, type, arg1); 8978 8979 if (! FLOAT_TYPE_P (type)) 8980 { 8981 if (integer_zerop (arg0)) 8982 return negate_expr (fold_convert (type, arg1)); 8983 if (integer_zerop (arg1)) 8984 return non_lvalue (fold_convert (type, arg0)); 8985 8986 /* Fold A - (A & B) into ~B & A. */ 8987 if (!TREE_SIDE_EFFECTS (arg0) 8988 && TREE_CODE (arg1) == BIT_AND_EXPR) 8989 { 8990 if (operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0)) 8991 return fold_build2 (BIT_AND_EXPR, type, 8992 fold_build1 (BIT_NOT_EXPR, type, 8993 TREE_OPERAND (arg1, 0)), 8994 arg0); 8995 if (operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 8996 return fold_build2 (BIT_AND_EXPR, type, 8997 fold_build1 (BIT_NOT_EXPR, type, 8998 TREE_OPERAND (arg1, 1)), 8999 arg0); 9000 } 9001 9002 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is 9003 any power of 2 minus 1. */ 9004 if (TREE_CODE (arg0) == BIT_AND_EXPR 9005 && TREE_CODE (arg1) == BIT_AND_EXPR 9006 && operand_equal_p (TREE_OPERAND (arg0, 0), 9007 TREE_OPERAND (arg1, 0), 0)) 9008 { 9009 tree mask0 = TREE_OPERAND (arg0, 1); 9010 tree mask1 = TREE_OPERAND (arg1, 1); 9011 tree tem = fold_build1 (BIT_NOT_EXPR, type, mask0); 9012 9013 if (operand_equal_p (tem, mask1, 0)) 9014 { 9015 tem = fold_build2 (BIT_XOR_EXPR, type, 9016 TREE_OPERAND (arg0, 0), mask1); 9017 return fold_build2 (MINUS_EXPR, type, tem, mask1); 9018 } 9019 } 9020 } 9021 9022 /* See if ARG1 is zero and X - ARG1 reduces to X. */ 9023 else if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 1)) 9024 return non_lvalue (fold_convert (type, arg0)); 9025 9026 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether 9027 ARG0 is zero and X + ARG0 reduces to X, since that would mean 9028 (-ARG1 + ARG0) reduces to -ARG1. */ 9029 else if (fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0)) 9030 return negate_expr (fold_convert (type, arg1)); 9031 9032 /* Fold &x - &x. This can happen from &x.foo - &x. 9033 This is unsafe for certain floats even in non-IEEE formats. 9034 In IEEE, it is unsafe because it does wrong for NaNs. 9035 Also note that operand_equal_p is always false if an operand 9036 is volatile. */ 9037 9038 if ((! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations) 9039 && operand_equal_p (arg0, arg1, 0)) 9040 return fold_convert (type, integer_zero_node); 9041 9042 /* A - B -> A + (-B) if B is easily negatable. */ 9043 if (negate_expr_p (arg1) 9044 && ((FLOAT_TYPE_P (type) 9045 /* Avoid this transformation if B is a positive REAL_CST. */ 9046 && (TREE_CODE (arg1) != REAL_CST 9047 || REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg1)))) 9048 || (INTEGRAL_TYPE_P (type) && flag_wrapv && !flag_trapv))) 9049 return fold_build2 (PLUS_EXPR, type, 9050 fold_convert (type, arg0), 9051 fold_convert (type, negate_expr (arg1))); 9052 9053 /* Try folding difference of addresses. */ 9054 { 9055 HOST_WIDE_INT diff; 9056 9057 if ((TREE_CODE (arg0) == ADDR_EXPR 9058 || TREE_CODE (arg1) == ADDR_EXPR) 9059 && ptr_difference_const (arg0, arg1, &diff)) 9060 return build_int_cst_type (type, diff); 9061 } 9062 9063 /* Fold &a[i] - &a[j] to i-j. */ 9064 if (TREE_CODE (arg0) == ADDR_EXPR 9065 && TREE_CODE (TREE_OPERAND (arg0, 0)) == ARRAY_REF 9066 && TREE_CODE (arg1) == ADDR_EXPR 9067 && TREE_CODE (TREE_OPERAND (arg1, 0)) == ARRAY_REF) 9068 { 9069 tree aref0 = TREE_OPERAND (arg0, 0); 9070 tree aref1 = TREE_OPERAND (arg1, 0); 9071 if (operand_equal_p (TREE_OPERAND (aref0, 0), 9072 TREE_OPERAND (aref1, 0), 0)) 9073 { 9074 tree op0 = fold_convert (type, TREE_OPERAND (aref0, 1)); 9075 tree op1 = fold_convert (type, TREE_OPERAND (aref1, 1)); 9076 tree esz = array_ref_element_size (aref0); 9077 tree diff = build2 (MINUS_EXPR, type, op0, op1); 9078 return fold_build2 (MULT_EXPR, type, diff, 9079 fold_convert (type, esz)); 9080 9081 } 9082 } 9083 9084 /* Try replacing &a[i1] - c * i2 with &a[i1 - i2], if c is step 9085 of the array. Loop optimizer sometimes produce this type of 9086 expressions. */ 9087 if (TREE_CODE (arg0) == ADDR_EXPR) 9088 { 9089 tem = try_move_mult_to_index (MINUS_EXPR, arg0, arg1); 9090 if (tem) 9091 return fold_convert (type, tem); 9092 } 9093 9094 if (flag_unsafe_math_optimizations 9095 && (TREE_CODE (arg0) == RDIV_EXPR || TREE_CODE (arg0) == MULT_EXPR) 9096 && (TREE_CODE (arg1) == RDIV_EXPR || TREE_CODE (arg1) == MULT_EXPR) 9097 && (tem = distribute_real_division (code, type, arg0, arg1))) 9098 return tem; 9099 9100 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the 9101 same or one. */ 9102 if ((TREE_CODE (arg0) == MULT_EXPR 9103 || TREE_CODE (arg1) == MULT_EXPR) 9104 && (!FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)) 9105 { 9106 tree tem = fold_plusminus_mult_expr (code, type, arg0, arg1); 9107 if (tem) 9108 return tem; 9109 } 9110 9111 goto associate; 9112 9113 case MULT_EXPR: 9114 /* (-A) * (-B) -> A * B */ 9115 if (TREE_CODE (arg0) == NEGATE_EXPR && negate_expr_p (arg1)) 9116 return fold_build2 (MULT_EXPR, type, 9117 fold_convert (type, TREE_OPERAND (arg0, 0)), 9118 fold_convert (type, negate_expr (arg1))); 9119 if (TREE_CODE (arg1) == NEGATE_EXPR && negate_expr_p (arg0)) 9120 return fold_build2 (MULT_EXPR, type, 9121 fold_convert (type, negate_expr (arg0)), 9122 fold_convert (type, TREE_OPERAND (arg1, 0))); 9123 9124 if (! FLOAT_TYPE_P (type)) 9125 { 9126 if (integer_zerop (arg1)) 9127 return omit_one_operand (type, arg1, arg0); 9128 if (integer_onep (arg1)) 9129 return non_lvalue (fold_convert (type, arg0)); 9130 /* Transform x * -1 into -x. */ 9131 if (integer_all_onesp (arg1)) 9132 return fold_convert (type, negate_expr (arg0)); 9133 9134 /* (a * (1 << b)) is (a << b) */ 9135 if (TREE_CODE (arg1) == LSHIFT_EXPR 9136 && integer_onep (TREE_OPERAND (arg1, 0))) 9137 return fold_build2 (LSHIFT_EXPR, type, arg0, 9138 TREE_OPERAND (arg1, 1)); 9139 if (TREE_CODE (arg0) == LSHIFT_EXPR 9140 && integer_onep (TREE_OPERAND (arg0, 0))) 9141 return fold_build2 (LSHIFT_EXPR, type, arg1, 9142 TREE_OPERAND (arg0, 1)); 9143 9144 strict_overflow_p = false; 9145 if (TREE_CODE (arg1) == INTEGER_CST 9146 && 0 != (tem = extract_muldiv (op0, 9147 fold_convert (type, arg1), 9148 code, NULL_TREE, 9149 &strict_overflow_p))) 9150 { 9151 if (strict_overflow_p) 9152 fold_overflow_warning (("assuming signed overflow does not " 9153 "occur when simplifying " 9154 "multiplication"), 9155 WARN_STRICT_OVERFLOW_MISC); 9156 return fold_convert (type, tem); 9157 } 9158 9159 /* Optimize z * conj(z) for integer complex numbers. */ 9160 if (TREE_CODE (arg0) == CONJ_EXPR 9161 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) 9162 return fold_mult_zconjz (type, arg1); 9163 if (TREE_CODE (arg1) == CONJ_EXPR 9164 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 9165 return fold_mult_zconjz (type, arg0); 9166 } 9167 else 9168 { 9169 /* Maybe fold x * 0 to 0. The expressions aren't the same 9170 when x is NaN, since x * 0 is also NaN. Nor are they the 9171 same in modes with signed zeros, since multiplying a 9172 negative value by 0 gives -0, not +0. */ 9173 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0))) 9174 && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg0))) 9175 && real_zerop (arg1)) 9176 return omit_one_operand (type, arg1, arg0); 9177 /* In IEEE floating point, x*1 is not equivalent to x for snans. */ 9178 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0))) 9179 && real_onep (arg1)) 9180 return non_lvalue (fold_convert (type, arg0)); 9181 9182 /* Transform x * -1.0 into -x. */ 9183 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0))) 9184 && real_minus_onep (arg1)) 9185 return fold_convert (type, negate_expr (arg0)); 9186 9187 /* Convert (C1/X)*C2 into (C1*C2)/X. */ 9188 if (flag_unsafe_math_optimizations 9189 && TREE_CODE (arg0) == RDIV_EXPR 9190 && TREE_CODE (arg1) == REAL_CST 9191 && TREE_CODE (TREE_OPERAND (arg0, 0)) == REAL_CST) 9192 { 9193 tree tem = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 0), 9194 arg1, 0); 9195 if (tem) 9196 return fold_build2 (RDIV_EXPR, type, tem, 9197 TREE_OPERAND (arg0, 1)); 9198 } 9199 9200 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */ 9201 if (operand_equal_p (arg0, arg1, 0)) 9202 { 9203 tree tem = fold_strip_sign_ops (arg0); 9204 if (tem != NULL_TREE) 9205 { 9206 tem = fold_convert (type, tem); 9207 return fold_build2 (MULT_EXPR, type, tem, tem); 9208 } 9209 } 9210 9211 /* Optimize z * conj(z) for floating point complex numbers. 9212 Guarded by flag_unsafe_math_optimizations as non-finite 9213 imaginary components don't produce scalar results. */ 9214 if (flag_unsafe_math_optimizations 9215 && TREE_CODE (arg0) == CONJ_EXPR 9216 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) 9217 return fold_mult_zconjz (type, arg1); 9218 if (flag_unsafe_math_optimizations 9219 && TREE_CODE (arg1) == CONJ_EXPR 9220 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 9221 return fold_mult_zconjz (type, arg0); 9222 9223 if (flag_unsafe_math_optimizations) 9224 { 9225 enum built_in_function fcode0 = builtin_mathfn_code (arg0); 9226 enum built_in_function fcode1 = builtin_mathfn_code (arg1); 9227 9228 /* Optimizations of root(...)*root(...). */ 9229 if (fcode0 == fcode1 && BUILTIN_ROOT_P (fcode0)) 9230 { 9231 tree rootfn, arg, arglist; 9232 tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1)); 9233 tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1)); 9234 9235 /* Optimize sqrt(x)*sqrt(x) as x. */ 9236 if (BUILTIN_SQRT_P (fcode0) 9237 && operand_equal_p (arg00, arg10, 0) 9238 && ! HONOR_SNANS (TYPE_MODE (type))) 9239 return arg00; 9240 9241 /* Optimize root(x)*root(y) as root(x*y). */ 9242 rootfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0); 9243 arg = fold_build2 (MULT_EXPR, type, arg00, arg10); 9244 arglist = build_tree_list (NULL_TREE, arg); 9245 return build_function_call_expr (rootfn, arglist); 9246 } 9247 9248 /* Optimize expN(x)*expN(y) as expN(x+y). */ 9249 if (fcode0 == fcode1 && BUILTIN_EXPONENT_P (fcode0)) 9250 { 9251 tree expfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0); 9252 tree arg = fold_build2 (PLUS_EXPR, type, 9253 TREE_VALUE (TREE_OPERAND (arg0, 1)), 9254 TREE_VALUE (TREE_OPERAND (arg1, 1))); 9255 tree arglist = build_tree_list (NULL_TREE, arg); 9256 return build_function_call_expr (expfn, arglist); 9257 } 9258 9259 /* Optimizations of pow(...)*pow(...). */ 9260 if ((fcode0 == BUILT_IN_POW && fcode1 == BUILT_IN_POW) 9261 || (fcode0 == BUILT_IN_POWF && fcode1 == BUILT_IN_POWF) 9262 || (fcode0 == BUILT_IN_POWL && fcode1 == BUILT_IN_POWL)) 9263 { 9264 tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1)); 9265 tree arg01 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg0, 9266 1))); 9267 tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1)); 9268 tree arg11 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg1, 9269 1))); 9270 9271 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */ 9272 if (operand_equal_p (arg01, arg11, 0)) 9273 { 9274 tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0); 9275 tree arg = fold_build2 (MULT_EXPR, type, arg00, arg10); 9276 tree arglist = tree_cons (NULL_TREE, arg, 9277 build_tree_list (NULL_TREE, 9278 arg01)); 9279 return build_function_call_expr (powfn, arglist); 9280 } 9281 9282 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */ 9283 if (operand_equal_p (arg00, arg10, 0)) 9284 { 9285 tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0); 9286 tree arg = fold_build2 (PLUS_EXPR, type, arg01, arg11); 9287 tree arglist = tree_cons (NULL_TREE, arg00, 9288 build_tree_list (NULL_TREE, 9289 arg)); 9290 return build_function_call_expr (powfn, arglist); 9291 } 9292 } 9293 9294 /* Optimize tan(x)*cos(x) as sin(x). */ 9295 if (((fcode0 == BUILT_IN_TAN && fcode1 == BUILT_IN_COS) 9296 || (fcode0 == BUILT_IN_TANF && fcode1 == BUILT_IN_COSF) 9297 || (fcode0 == BUILT_IN_TANL && fcode1 == BUILT_IN_COSL) 9298 || (fcode0 == BUILT_IN_COS && fcode1 == BUILT_IN_TAN) 9299 || (fcode0 == BUILT_IN_COSF && fcode1 == BUILT_IN_TANF) 9300 || (fcode0 == BUILT_IN_COSL && fcode1 == BUILT_IN_TANL)) 9301 && operand_equal_p (TREE_VALUE (TREE_OPERAND (arg0, 1)), 9302 TREE_VALUE (TREE_OPERAND (arg1, 1)), 0)) 9303 { 9304 tree sinfn = mathfn_built_in (type, BUILT_IN_SIN); 9305 9306 if (sinfn != NULL_TREE) 9307 return build_function_call_expr (sinfn, 9308 TREE_OPERAND (arg0, 1)); 9309 } 9310 9311 /* Optimize x*pow(x,c) as pow(x,c+1). */ 9312 if (fcode1 == BUILT_IN_POW 9313 || fcode1 == BUILT_IN_POWF 9314 || fcode1 == BUILT_IN_POWL) 9315 { 9316 tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1)); 9317 tree arg11 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg1, 9318 1))); 9319 if (TREE_CODE (arg11) == REAL_CST 9320 && ! TREE_CONSTANT_OVERFLOW (arg11) 9321 && operand_equal_p (arg0, arg10, 0)) 9322 { 9323 tree powfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0); 9324 REAL_VALUE_TYPE c; 9325 tree arg, arglist; 9326 9327 c = TREE_REAL_CST (arg11); 9328 real_arithmetic (&c, PLUS_EXPR, &c, &dconst1); 9329 arg = build_real (type, c); 9330 arglist = build_tree_list (NULL_TREE, arg); 9331 arglist = tree_cons (NULL_TREE, arg0, arglist); 9332 return build_function_call_expr (powfn, arglist); 9333 } 9334 } 9335 9336 /* Optimize pow(x,c)*x as pow(x,c+1). */ 9337 if (fcode0 == BUILT_IN_POW 9338 || fcode0 == BUILT_IN_POWF 9339 || fcode0 == BUILT_IN_POWL) 9340 { 9341 tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1)); 9342 tree arg01 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg0, 9343 1))); 9344 if (TREE_CODE (arg01) == REAL_CST 9345 && ! TREE_CONSTANT_OVERFLOW (arg01) 9346 && operand_equal_p (arg1, arg00, 0)) 9347 { 9348 tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0); 9349 REAL_VALUE_TYPE c; 9350 tree arg, arglist; 9351 9352 c = TREE_REAL_CST (arg01); 9353 real_arithmetic (&c, PLUS_EXPR, &c, &dconst1); 9354 arg = build_real (type, c); 9355 arglist = build_tree_list (NULL_TREE, arg); 9356 arglist = tree_cons (NULL_TREE, arg1, arglist); 9357 return build_function_call_expr (powfn, arglist); 9358 } 9359 } 9360 9361 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */ 9362 if (! optimize_size 9363 && operand_equal_p (arg0, arg1, 0)) 9364 { 9365 tree powfn = mathfn_built_in (type, BUILT_IN_POW); 9366 9367 if (powfn) 9368 { 9369 tree arg = build_real (type, dconst2); 9370 tree arglist = build_tree_list (NULL_TREE, arg); 9371 arglist = tree_cons (NULL_TREE, arg0, arglist); 9372 return build_function_call_expr (powfn, arglist); 9373 } 9374 } 9375 } 9376 } 9377 goto associate; 9378 9379 case BIT_IOR_EXPR: 9380 bit_ior: 9381 if (integer_all_onesp (arg1)) 9382 return omit_one_operand (type, arg1, arg0); 9383 if (integer_zerop (arg1)) 9384 return non_lvalue (fold_convert (type, arg0)); 9385 if (operand_equal_p (arg0, arg1, 0)) 9386 return non_lvalue (fold_convert (type, arg0)); 9387 9388 /* ~X | X is -1. */ 9389 if (TREE_CODE (arg0) == BIT_NOT_EXPR 9390 && INTEGRAL_TYPE_P (TREE_TYPE (arg1)) 9391 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) 9392 { 9393 t1 = build_int_cst (type, -1); 9394 t1 = force_fit_type (t1, 0, false, false); 9395 return omit_one_operand (type, t1, arg1); 9396 } 9397 9398 /* X | ~X is -1. */ 9399 if (TREE_CODE (arg1) == BIT_NOT_EXPR 9400 && INTEGRAL_TYPE_P (TREE_TYPE (arg0)) 9401 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 9402 { 9403 t1 = build_int_cst (type, -1); 9404 t1 = force_fit_type (t1, 0, false, false); 9405 return omit_one_operand (type, t1, arg0); 9406 } 9407 9408 /* Canonicalize (X & C1) | C2. */ 9409 if (TREE_CODE (arg0) == BIT_AND_EXPR 9410 && TREE_CODE (arg1) == INTEGER_CST 9411 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) 9412 { 9413 unsigned HOST_WIDE_INT hi1, lo1, hi2, lo2, mlo, mhi; 9414 int width = TYPE_PRECISION (type); 9415 hi1 = TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)); 9416 lo1 = TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)); 9417 hi2 = TREE_INT_CST_HIGH (arg1); 9418 lo2 = TREE_INT_CST_LOW (arg1); 9419 9420 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */ 9421 if ((hi1 & hi2) == hi1 && (lo1 & lo2) == lo1) 9422 return omit_one_operand (type, arg1, TREE_OPERAND (arg0, 0)); 9423 9424 if (width > HOST_BITS_PER_WIDE_INT) 9425 { 9426 mhi = (unsigned HOST_WIDE_INT) -1 9427 >> (2 * HOST_BITS_PER_WIDE_INT - width); 9428 mlo = -1; 9429 } 9430 else 9431 { 9432 mhi = 0; 9433 mlo = (unsigned HOST_WIDE_INT) -1 9434 >> (HOST_BITS_PER_WIDE_INT - width); 9435 } 9436 9437 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */ 9438 if ((~(hi1 | hi2) & mhi) == 0 && (~(lo1 | lo2) & mlo) == 0) 9439 return fold_build2 (BIT_IOR_EXPR, type, 9440 TREE_OPERAND (arg0, 0), arg1); 9441 9442 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2. */ 9443 hi1 &= mhi; 9444 lo1 &= mlo; 9445 if ((hi1 & ~hi2) != hi1 || (lo1 & ~lo2) != lo1) 9446 return fold_build2 (BIT_IOR_EXPR, type, 9447 fold_build2 (BIT_AND_EXPR, type, 9448 TREE_OPERAND (arg0, 0), 9449 build_int_cst_wide (type, 9450 lo1 & ~lo2, 9451 hi1 & ~hi2)), 9452 arg1); 9453 } 9454 9455 /* (X & Y) | Y is (X, Y). */ 9456 if (TREE_CODE (arg0) == BIT_AND_EXPR 9457 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) 9458 return omit_one_operand (type, arg1, TREE_OPERAND (arg0, 0)); 9459 /* (X & Y) | X is (Y, X). */ 9460 if (TREE_CODE (arg0) == BIT_AND_EXPR 9461 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) 9462 && reorder_operands_p (TREE_OPERAND (arg0, 1), arg1)) 9463 return omit_one_operand (type, arg1, TREE_OPERAND (arg0, 1)); 9464 /* X | (X & Y) is (Y, X). */ 9465 if (TREE_CODE (arg1) == BIT_AND_EXPR 9466 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0) 9467 && reorder_operands_p (arg0, TREE_OPERAND (arg1, 1))) 9468 return omit_one_operand (type, arg0, TREE_OPERAND (arg1, 1)); 9469 /* X | (Y & X) is (Y, X). */ 9470 if (TREE_CODE (arg1) == BIT_AND_EXPR 9471 && operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0) 9472 && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0))) 9473 return omit_one_operand (type, arg0, TREE_OPERAND (arg1, 0)); 9474 9475 t1 = distribute_bit_expr (code, type, arg0, arg1); 9476 if (t1 != NULL_TREE) 9477 return t1; 9478 9479 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))). 9480 9481 This results in more efficient code for machines without a NAND 9482 instruction. Combine will canonicalize to the first form 9483 which will allow use of NAND instructions provided by the 9484 backend if they exist. */ 9485 if (TREE_CODE (arg0) == BIT_NOT_EXPR 9486 && TREE_CODE (arg1) == BIT_NOT_EXPR) 9487 { 9488 return fold_build1 (BIT_NOT_EXPR, type, 9489 build2 (BIT_AND_EXPR, type, 9490 TREE_OPERAND (arg0, 0), 9491 TREE_OPERAND (arg1, 0))); 9492 } 9493 9494 /* See if this can be simplified into a rotate first. If that 9495 is unsuccessful continue in the association code. */ 9496 goto bit_rotate; 9497 9498 case BIT_XOR_EXPR: 9499 if (integer_zerop (arg1)) 9500 return non_lvalue (fold_convert (type, arg0)); 9501 if (integer_all_onesp (arg1)) 9502 return fold_build1 (BIT_NOT_EXPR, type, arg0); 9503 if (operand_equal_p (arg0, arg1, 0)) 9504 return omit_one_operand (type, integer_zero_node, arg0); 9505 9506 /* ~X ^ X is -1. */ 9507 if (TREE_CODE (arg0) == BIT_NOT_EXPR 9508 && INTEGRAL_TYPE_P (TREE_TYPE (arg1)) 9509 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) 9510 { 9511 t1 = build_int_cst (type, -1); 9512 t1 = force_fit_type (t1, 0, false, false); 9513 return omit_one_operand (type, t1, arg1); 9514 } 9515 9516 /* X ^ ~X is -1. */ 9517 if (TREE_CODE (arg1) == BIT_NOT_EXPR 9518 && INTEGRAL_TYPE_P (TREE_TYPE (arg0)) 9519 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 9520 { 9521 t1 = build_int_cst (type, -1); 9522 t1 = force_fit_type (t1, 0, false, false); 9523 return omit_one_operand (type, t1, arg0); 9524 } 9525 9526 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing 9527 with a constant, and the two constants have no bits in common, 9528 we should treat this as a BIT_IOR_EXPR since this may produce more 9529 simplifications. */ 9530 if (TREE_CODE (arg0) == BIT_AND_EXPR 9531 && TREE_CODE (arg1) == BIT_AND_EXPR 9532 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST 9533 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST 9534 && integer_zerop (const_binop (BIT_AND_EXPR, 9535 TREE_OPERAND (arg0, 1), 9536 TREE_OPERAND (arg1, 1), 0))) 9537 { 9538 code = BIT_IOR_EXPR; 9539 goto bit_ior; 9540 } 9541 9542 /* (X | Y) ^ X -> Y & ~ X*/ 9543 if (TREE_CODE (arg0) == BIT_IOR_EXPR 9544 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) 9545 { 9546 tree t2 = TREE_OPERAND (arg0, 1); 9547 t1 = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (arg1), 9548 arg1); 9549 t1 = fold_build2 (BIT_AND_EXPR, type, fold_convert (type, t2), 9550 fold_convert (type, t1)); 9551 return t1; 9552 } 9553 9554 /* (Y | X) ^ X -> Y & ~ X*/ 9555 if (TREE_CODE (arg0) == BIT_IOR_EXPR 9556 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) 9557 { 9558 tree t2 = TREE_OPERAND (arg0, 0); 9559 t1 = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (arg1), 9560 arg1); 9561 t1 = fold_build2 (BIT_AND_EXPR, type, fold_convert (type, t2), 9562 fold_convert (type, t1)); 9563 return t1; 9564 } 9565 9566 /* X ^ (X | Y) -> Y & ~ X*/ 9567 if (TREE_CODE (arg1) == BIT_IOR_EXPR 9568 && operand_equal_p (TREE_OPERAND (arg1, 0), arg0, 0)) 9569 { 9570 tree t2 = TREE_OPERAND (arg1, 1); 9571 t1 = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (arg0), 9572 arg0); 9573 t1 = fold_build2 (BIT_AND_EXPR, type, fold_convert (type, t2), 9574 fold_convert (type, t1)); 9575 return t1; 9576 } 9577 9578 /* X ^ (Y | X) -> Y & ~ X*/ 9579 if (TREE_CODE (arg1) == BIT_IOR_EXPR 9580 && operand_equal_p (TREE_OPERAND (arg1, 1), arg0, 0)) 9581 { 9582 tree t2 = TREE_OPERAND (arg1, 0); 9583 t1 = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (arg0), 9584 arg0); 9585 t1 = fold_build2 (BIT_AND_EXPR, type, fold_convert (type, t2), 9586 fold_convert (type, t1)); 9587 return t1; 9588 } 9589 9590 /* Convert ~X ^ ~Y to X ^ Y. */ 9591 if (TREE_CODE (arg0) == BIT_NOT_EXPR 9592 && TREE_CODE (arg1) == BIT_NOT_EXPR) 9593 return fold_build2 (code, type, 9594 fold_convert (type, TREE_OPERAND (arg0, 0)), 9595 fold_convert (type, TREE_OPERAND (arg1, 0))); 9596 9597 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */ 9598 if (TREE_CODE (arg0) == BIT_AND_EXPR 9599 && integer_onep (TREE_OPERAND (arg0, 1)) 9600 && integer_onep (arg1)) 9601 return fold_build2 (EQ_EXPR, type, arg0, 9602 build_int_cst (TREE_TYPE (arg0), 0)); 9603 9604 /* Fold (X & Y) ^ Y as ~X & Y. */ 9605 if (TREE_CODE (arg0) == BIT_AND_EXPR 9606 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) 9607 { 9608 tem = fold_convert (type, TREE_OPERAND (arg0, 0)); 9609 return fold_build2 (BIT_AND_EXPR, type, 9610 fold_build1 (BIT_NOT_EXPR, type, tem), 9611 fold_convert (type, arg1)); 9612 } 9613 /* Fold (X & Y) ^ X as ~Y & X. */ 9614 if (TREE_CODE (arg0) == BIT_AND_EXPR 9615 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) 9616 && reorder_operands_p (TREE_OPERAND (arg0, 1), arg1)) 9617 { 9618 tem = fold_convert (type, TREE_OPERAND (arg0, 1)); 9619 return fold_build2 (BIT_AND_EXPR, type, 9620 fold_build1 (BIT_NOT_EXPR, type, tem), 9621 fold_convert (type, arg1)); 9622 } 9623 /* Fold X ^ (X & Y) as X & ~Y. */ 9624 if (TREE_CODE (arg1) == BIT_AND_EXPR 9625 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 9626 { 9627 tem = fold_convert (type, TREE_OPERAND (arg1, 1)); 9628 return fold_build2 (BIT_AND_EXPR, type, 9629 fold_convert (type, arg0), 9630 fold_build1 (BIT_NOT_EXPR, type, tem)); 9631 } 9632 /* Fold X ^ (Y & X) as ~Y & X. */ 9633 if (TREE_CODE (arg1) == BIT_AND_EXPR 9634 && operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0) 9635 && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0))) 9636 { 9637 tem = fold_convert (type, TREE_OPERAND (arg1, 0)); 9638 return fold_build2 (BIT_AND_EXPR, type, 9639 fold_build1 (BIT_NOT_EXPR, type, tem), 9640 fold_convert (type, arg0)); 9641 } 9642 9643 /* See if this can be simplified into a rotate first. If that 9644 is unsuccessful continue in the association code. */ 9645 goto bit_rotate; 9646 9647 case BIT_AND_EXPR: 9648 if (integer_all_onesp (arg1)) 9649 return non_lvalue (fold_convert (type, arg0)); 9650 if (integer_zerop (arg1)) 9651 return omit_one_operand (type, arg1, arg0); 9652 if (operand_equal_p (arg0, arg1, 0)) 9653 return non_lvalue (fold_convert (type, arg0)); 9654 9655 /* ~X & X is always zero. */ 9656 if (TREE_CODE (arg0) == BIT_NOT_EXPR 9657 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) 9658 return omit_one_operand (type, integer_zero_node, arg1); 9659 9660 /* X & ~X is always zero. */ 9661 if (TREE_CODE (arg1) == BIT_NOT_EXPR 9662 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 9663 return omit_one_operand (type, integer_zero_node, arg0); 9664 9665 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */ 9666 if (TREE_CODE (arg0) == BIT_IOR_EXPR 9667 && TREE_CODE (arg1) == INTEGER_CST 9668 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) 9669 return fold_build2 (BIT_IOR_EXPR, type, 9670 fold_build2 (BIT_AND_EXPR, type, 9671 TREE_OPERAND (arg0, 0), arg1), 9672 fold_build2 (BIT_AND_EXPR, type, 9673 TREE_OPERAND (arg0, 1), arg1)); 9674 9675 /* (X | Y) & Y is (X, Y). */ 9676 if (TREE_CODE (arg0) == BIT_IOR_EXPR 9677 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) 9678 return omit_one_operand (type, arg1, TREE_OPERAND (arg0, 0)); 9679 /* (X | Y) & X is (Y, X). */ 9680 if (TREE_CODE (arg0) == BIT_IOR_EXPR 9681 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) 9682 && reorder_operands_p (TREE_OPERAND (arg0, 1), arg1)) 9683 return omit_one_operand (type, arg1, TREE_OPERAND (arg0, 1)); 9684 /* X & (X | Y) is (Y, X). */ 9685 if (TREE_CODE (arg1) == BIT_IOR_EXPR 9686 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0) 9687 && reorder_operands_p (arg0, TREE_OPERAND (arg1, 1))) 9688 return omit_one_operand (type, arg0, TREE_OPERAND (arg1, 1)); 9689 /* X & (Y | X) is (Y, X). */ 9690 if (TREE_CODE (arg1) == BIT_IOR_EXPR 9691 && operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0) 9692 && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0))) 9693 return omit_one_operand (type, arg0, TREE_OPERAND (arg1, 0)); 9694 9695 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */ 9696 if (TREE_CODE (arg0) == BIT_XOR_EXPR 9697 && integer_onep (TREE_OPERAND (arg0, 1)) 9698 && integer_onep (arg1)) 9699 { 9700 tem = TREE_OPERAND (arg0, 0); 9701 return fold_build2 (EQ_EXPR, type, 9702 fold_build2 (BIT_AND_EXPR, TREE_TYPE (tem), tem, 9703 build_int_cst (TREE_TYPE (tem), 1)), 9704 build_int_cst (TREE_TYPE (tem), 0)); 9705 } 9706 /* Fold ~X & 1 as (X & 1) == 0. */ 9707 if (TREE_CODE (arg0) == BIT_NOT_EXPR 9708 && integer_onep (arg1)) 9709 { 9710 tem = TREE_OPERAND (arg0, 0); 9711 return fold_build2 (EQ_EXPR, type, 9712 fold_build2 (BIT_AND_EXPR, TREE_TYPE (tem), tem, 9713 build_int_cst (TREE_TYPE (tem), 1)), 9714 build_int_cst (TREE_TYPE (tem), 0)); 9715 } 9716 9717 /* Fold (X ^ Y) & Y as ~X & Y. */ 9718 if (TREE_CODE (arg0) == BIT_XOR_EXPR 9719 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) 9720 { 9721 tem = fold_convert (type, TREE_OPERAND (arg0, 0)); 9722 return fold_build2 (BIT_AND_EXPR, type, 9723 fold_build1 (BIT_NOT_EXPR, type, tem), 9724 fold_convert (type, arg1)); 9725 } 9726 /* Fold (X ^ Y) & X as ~Y & X. */ 9727 if (TREE_CODE (arg0) == BIT_XOR_EXPR 9728 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) 9729 && reorder_operands_p (TREE_OPERAND (arg0, 1), arg1)) 9730 { 9731 tem = fold_convert (type, TREE_OPERAND (arg0, 1)); 9732 return fold_build2 (BIT_AND_EXPR, type, 9733 fold_build1 (BIT_NOT_EXPR, type, tem), 9734 fold_convert (type, arg1)); 9735 } 9736 /* Fold X & (X ^ Y) as X & ~Y. */ 9737 if (TREE_CODE (arg1) == BIT_XOR_EXPR 9738 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 9739 { 9740 tem = fold_convert (type, TREE_OPERAND (arg1, 1)); 9741 return fold_build2 (BIT_AND_EXPR, type, 9742 fold_convert (type, arg0), 9743 fold_build1 (BIT_NOT_EXPR, type, tem)); 9744 } 9745 /* Fold X & (Y ^ X) as ~Y & X. */ 9746 if (TREE_CODE (arg1) == BIT_XOR_EXPR 9747 && operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0) 9748 && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0))) 9749 { 9750 tem = fold_convert (type, TREE_OPERAND (arg1, 0)); 9751 return fold_build2 (BIT_AND_EXPR, type, 9752 fold_build1 (BIT_NOT_EXPR, type, tem), 9753 fold_convert (type, arg0)); 9754 } 9755 9756 t1 = distribute_bit_expr (code, type, arg0, arg1); 9757 if (t1 != NULL_TREE) 9758 return t1; 9759 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */ 9760 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR 9761 && TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))) 9762 { 9763 unsigned int prec 9764 = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))); 9765 9766 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT 9767 && (~TREE_INT_CST_LOW (arg1) 9768 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0) 9769 return fold_convert (type, TREE_OPERAND (arg0, 0)); 9770 } 9771 9772 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))). 9773 9774 This results in more efficient code for machines without a NOR 9775 instruction. Combine will canonicalize to the first form 9776 which will allow use of NOR instructions provided by the 9777 backend if they exist. */ 9778 if (TREE_CODE (arg0) == BIT_NOT_EXPR 9779 && TREE_CODE (arg1) == BIT_NOT_EXPR) 9780 { 9781 return fold_build1 (BIT_NOT_EXPR, type, 9782 build2 (BIT_IOR_EXPR, type, 9783 TREE_OPERAND (arg0, 0), 9784 TREE_OPERAND (arg1, 0))); 9785 } 9786 9787 goto associate; 9788 9789 case RDIV_EXPR: 9790 /* Don't touch a floating-point divide by zero unless the mode 9791 of the constant can represent infinity. */ 9792 if (TREE_CODE (arg1) == REAL_CST 9793 && !MODE_HAS_INFINITIES (TYPE_MODE (TREE_TYPE (arg1))) 9794 && real_zerop (arg1)) 9795 return NULL_TREE; 9796 9797 /* Optimize A / A to 1.0 if we don't care about 9798 NaNs or Infinities. Skip the transformation 9799 for non-real operands. */ 9800 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (arg0)) 9801 && ! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0))) 9802 && ! HONOR_INFINITIES (TYPE_MODE (TREE_TYPE (arg0))) 9803 && operand_equal_p (arg0, arg1, 0)) 9804 { 9805 tree r = build_real (TREE_TYPE (arg0), dconst1); 9806 9807 return omit_two_operands (type, r, arg0, arg1); 9808 } 9809 9810 /* The complex version of the above A / A optimization. */ 9811 if (COMPLEX_FLOAT_TYPE_P (TREE_TYPE (arg0)) 9812 && operand_equal_p (arg0, arg1, 0)) 9813 { 9814 tree elem_type = TREE_TYPE (TREE_TYPE (arg0)); 9815 if (! HONOR_NANS (TYPE_MODE (elem_type)) 9816 && ! HONOR_INFINITIES (TYPE_MODE (elem_type))) 9817 { 9818 tree r = build_real (elem_type, dconst1); 9819 /* omit_two_operands will call fold_convert for us. */ 9820 return omit_two_operands (type, r, arg0, arg1); 9821 } 9822 } 9823 9824 /* (-A) / (-B) -> A / B */ 9825 if (TREE_CODE (arg0) == NEGATE_EXPR && negate_expr_p (arg1)) 9826 return fold_build2 (RDIV_EXPR, type, 9827 TREE_OPERAND (arg0, 0), 9828 negate_expr (arg1)); 9829 if (TREE_CODE (arg1) == NEGATE_EXPR && negate_expr_p (arg0)) 9830 return fold_build2 (RDIV_EXPR, type, 9831 negate_expr (arg0), 9832 TREE_OPERAND (arg1, 0)); 9833 9834 /* In IEEE floating point, x/1 is not equivalent to x for snans. */ 9835 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0))) 9836 && real_onep (arg1)) 9837 return non_lvalue (fold_convert (type, arg0)); 9838 9839 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */ 9840 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0))) 9841 && real_minus_onep (arg1)) 9842 return non_lvalue (fold_convert (type, negate_expr (arg0))); 9843 9844 /* If ARG1 is a constant, we can convert this to a multiply by the 9845 reciprocal. This does not have the same rounding properties, 9846 so only do this if -funsafe-math-optimizations. We can actually 9847 always safely do it if ARG1 is a power of two, but it's hard to 9848 tell if it is or not in a portable manner. */ 9849 if (TREE_CODE (arg1) == REAL_CST) 9850 { 9851 if (flag_unsafe_math_optimizations 9852 && 0 != (tem = const_binop (code, build_real (type, dconst1), 9853 arg1, 0))) 9854 return fold_build2 (MULT_EXPR, type, arg0, tem); 9855 /* Find the reciprocal if optimizing and the result is exact. */ 9856 if (optimize) 9857 { 9858 REAL_VALUE_TYPE r; 9859 r = TREE_REAL_CST (arg1); 9860 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r)) 9861 { 9862 tem = build_real (type, r); 9863 return fold_build2 (MULT_EXPR, type, 9864 fold_convert (type, arg0), tem); 9865 } 9866 } 9867 } 9868 /* Convert A/B/C to A/(B*C). */ 9869 if (flag_unsafe_math_optimizations 9870 && TREE_CODE (arg0) == RDIV_EXPR) 9871 return fold_build2 (RDIV_EXPR, type, TREE_OPERAND (arg0, 0), 9872 fold_build2 (MULT_EXPR, type, 9873 TREE_OPERAND (arg0, 1), arg1)); 9874 9875 /* Convert A/(B/C) to (A/B)*C. */ 9876 if (flag_unsafe_math_optimizations 9877 && TREE_CODE (arg1) == RDIV_EXPR) 9878 return fold_build2 (MULT_EXPR, type, 9879 fold_build2 (RDIV_EXPR, type, arg0, 9880 TREE_OPERAND (arg1, 0)), 9881 TREE_OPERAND (arg1, 1)); 9882 9883 /* Convert C1/(X*C2) into (C1/C2)/X. */ 9884 if (flag_unsafe_math_optimizations 9885 && TREE_CODE (arg1) == MULT_EXPR 9886 && TREE_CODE (arg0) == REAL_CST 9887 && TREE_CODE (TREE_OPERAND (arg1, 1)) == REAL_CST) 9888 { 9889 tree tem = const_binop (RDIV_EXPR, arg0, 9890 TREE_OPERAND (arg1, 1), 0); 9891 if (tem) 9892 return fold_build2 (RDIV_EXPR, type, tem, 9893 TREE_OPERAND (arg1, 0)); 9894 } 9895 9896 if (flag_unsafe_math_optimizations) 9897 { 9898 enum built_in_function fcode0 = builtin_mathfn_code (arg0); 9899 enum built_in_function fcode1 = builtin_mathfn_code (arg1); 9900 9901 /* Optimize sin(x)/cos(x) as tan(x). */ 9902 if (((fcode0 == BUILT_IN_SIN && fcode1 == BUILT_IN_COS) 9903 || (fcode0 == BUILT_IN_SINF && fcode1 == BUILT_IN_COSF) 9904 || (fcode0 == BUILT_IN_SINL && fcode1 == BUILT_IN_COSL)) 9905 && operand_equal_p (TREE_VALUE (TREE_OPERAND (arg0, 1)), 9906 TREE_VALUE (TREE_OPERAND (arg1, 1)), 0)) 9907 { 9908 tree tanfn = mathfn_built_in (type, BUILT_IN_TAN); 9909 9910 if (tanfn != NULL_TREE) 9911 return build_function_call_expr (tanfn, 9912 TREE_OPERAND (arg0, 1)); 9913 } 9914 9915 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */ 9916 if (((fcode0 == BUILT_IN_COS && fcode1 == BUILT_IN_SIN) 9917 || (fcode0 == BUILT_IN_COSF && fcode1 == BUILT_IN_SINF) 9918 || (fcode0 == BUILT_IN_COSL && fcode1 == BUILT_IN_SINL)) 9919 && operand_equal_p (TREE_VALUE (TREE_OPERAND (arg0, 1)), 9920 TREE_VALUE (TREE_OPERAND (arg1, 1)), 0)) 9921 { 9922 tree tanfn = mathfn_built_in (type, BUILT_IN_TAN); 9923 9924 if (tanfn != NULL_TREE) 9925 { 9926 tree tmp = TREE_OPERAND (arg0, 1); 9927 tmp = build_function_call_expr (tanfn, tmp); 9928 return fold_build2 (RDIV_EXPR, type, 9929 build_real (type, dconst1), tmp); 9930 } 9931 } 9932 9933 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about 9934 NaNs or Infinities. */ 9935 if (((fcode0 == BUILT_IN_SIN && fcode1 == BUILT_IN_TAN) 9936 || (fcode0 == BUILT_IN_SINF && fcode1 == BUILT_IN_TANF) 9937 || (fcode0 == BUILT_IN_SINL && fcode1 == BUILT_IN_TANL))) 9938 { 9939 tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1)); 9940 tree arg01 = TREE_VALUE (TREE_OPERAND (arg1, 1)); 9941 9942 if (! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg00))) 9943 && ! HONOR_INFINITIES (TYPE_MODE (TREE_TYPE (arg00))) 9944 && operand_equal_p (arg00, arg01, 0)) 9945 { 9946 tree cosfn = mathfn_built_in (type, BUILT_IN_COS); 9947 9948 if (cosfn != NULL_TREE) 9949 return build_function_call_expr (cosfn, 9950 TREE_OPERAND (arg0, 1)); 9951 } 9952 } 9953 9954 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about 9955 NaNs or Infinities. */ 9956 if (((fcode0 == BUILT_IN_TAN && fcode1 == BUILT_IN_SIN) 9957 || (fcode0 == BUILT_IN_TANF && fcode1 == BUILT_IN_SINF) 9958 || (fcode0 == BUILT_IN_TANL && fcode1 == BUILT_IN_SINL))) 9959 { 9960 tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1)); 9961 tree arg01 = TREE_VALUE (TREE_OPERAND (arg1, 1)); 9962 9963 if (! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg00))) 9964 && ! HONOR_INFINITIES (TYPE_MODE (TREE_TYPE (arg00))) 9965 && operand_equal_p (arg00, arg01, 0)) 9966 { 9967 tree cosfn = mathfn_built_in (type, BUILT_IN_COS); 9968 9969 if (cosfn != NULL_TREE) 9970 { 9971 tree tmp = TREE_OPERAND (arg0, 1); 9972 tmp = build_function_call_expr (cosfn, tmp); 9973 return fold_build2 (RDIV_EXPR, type, 9974 build_real (type, dconst1), 9975 tmp); 9976 } 9977 } 9978 } 9979 9980 /* Optimize pow(x,c)/x as pow(x,c-1). */ 9981 if (fcode0 == BUILT_IN_POW 9982 || fcode0 == BUILT_IN_POWF 9983 || fcode0 == BUILT_IN_POWL) 9984 { 9985 tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1)); 9986 tree arg01 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg0, 1))); 9987 if (TREE_CODE (arg01) == REAL_CST 9988 && ! TREE_CONSTANT_OVERFLOW (arg01) 9989 && operand_equal_p (arg1, arg00, 0)) 9990 { 9991 tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0); 9992 REAL_VALUE_TYPE c; 9993 tree arg, arglist; 9994 9995 c = TREE_REAL_CST (arg01); 9996 real_arithmetic (&c, MINUS_EXPR, &c, &dconst1); 9997 arg = build_real (type, c); 9998 arglist = build_tree_list (NULL_TREE, arg); 9999 arglist = tree_cons (NULL_TREE, arg1, arglist); 10000 return build_function_call_expr (powfn, arglist); 10001 } 10002 } 10003 10004 /* Optimize x/expN(y) into x*expN(-y). */ 10005 if (BUILTIN_EXPONENT_P (fcode1)) 10006 { 10007 tree expfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0); 10008 tree arg = negate_expr (TREE_VALUE (TREE_OPERAND (arg1, 1))); 10009 tree arglist = build_tree_list (NULL_TREE, 10010 fold_convert (type, arg)); 10011 arg1 = build_function_call_expr (expfn, arglist); 10012 return fold_build2 (MULT_EXPR, type, arg0, arg1); 10013 } 10014 10015 /* Optimize x/pow(y,z) into x*pow(y,-z). */ 10016 if (fcode1 == BUILT_IN_POW 10017 || fcode1 == BUILT_IN_POWF 10018 || fcode1 == BUILT_IN_POWL) 10019 { 10020 tree powfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0); 10021 tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1)); 10022 tree arg11 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg1, 1))); 10023 tree neg11 = fold_convert (type, negate_expr (arg11)); 10024 tree arglist = tree_cons(NULL_TREE, arg10, 10025 build_tree_list (NULL_TREE, neg11)); 10026 arg1 = build_function_call_expr (powfn, arglist); 10027 return fold_build2 (MULT_EXPR, type, arg0, arg1); 10028 } 10029 } 10030 return NULL_TREE; 10031 10032 case TRUNC_DIV_EXPR: 10033 case FLOOR_DIV_EXPR: 10034 /* Simplify A / (B << N) where A and B are positive and B is 10035 a power of 2, to A >> (N + log2(B)). */ 10036 strict_overflow_p = false; 10037 if (TREE_CODE (arg1) == LSHIFT_EXPR 10038 && (TYPE_UNSIGNED (type) 10039 || tree_expr_nonnegative_warnv_p (arg0, &strict_overflow_p))) 10040 { 10041 tree sval = TREE_OPERAND (arg1, 0); 10042 if (integer_pow2p (sval) && tree_int_cst_sgn (sval) > 0) 10043 { 10044 tree sh_cnt = TREE_OPERAND (arg1, 1); 10045 unsigned long pow2 = exact_log2 (TREE_INT_CST_LOW (sval)); 10046 10047 if (strict_overflow_p) 10048 fold_overflow_warning (("assuming signed overflow does not " 10049 "occur when simplifying A / (B << N)"), 10050 WARN_STRICT_OVERFLOW_MISC); 10051 10052 sh_cnt = fold_build2 (PLUS_EXPR, TREE_TYPE (sh_cnt), 10053 sh_cnt, build_int_cst (NULL_TREE, pow2)); 10054 return fold_build2 (RSHIFT_EXPR, type, 10055 fold_convert (type, arg0), sh_cnt); 10056 } 10057 } 10058 /* Fall thru */ 10059 10060 case ROUND_DIV_EXPR: 10061 case CEIL_DIV_EXPR: 10062 case EXACT_DIV_EXPR: 10063 if (integer_onep (arg1)) 10064 return non_lvalue (fold_convert (type, arg0)); 10065 if (integer_zerop (arg1)) 10066 return NULL_TREE; 10067 /* X / -1 is -X. */ 10068 if (!TYPE_UNSIGNED (type) 10069 && TREE_CODE (arg1) == INTEGER_CST 10070 && TREE_INT_CST_LOW (arg1) == (unsigned HOST_WIDE_INT) -1 10071 && TREE_INT_CST_HIGH (arg1) == -1) 10072 return fold_convert (type, negate_expr (arg0)); 10073 10074 /* Convert -A / -B to A / B when the type is signed and overflow is 10075 undefined. */ 10076 if ((!INTEGRAL_TYPE_P (type) || TYPE_OVERFLOW_UNDEFINED (type)) 10077 && TREE_CODE (arg0) == NEGATE_EXPR 10078 && negate_expr_p (arg1)) 10079 { 10080 if (INTEGRAL_TYPE_P (type)) 10081 fold_overflow_warning (("assuming signed overflow does not occur " 10082 "when distributing negation across " 10083 "division"), 10084 WARN_STRICT_OVERFLOW_MISC); 10085 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), 10086 negate_expr (arg1)); 10087 } 10088 if ((!INTEGRAL_TYPE_P (type) || TYPE_OVERFLOW_UNDEFINED (type)) 10089 && TREE_CODE (arg1) == NEGATE_EXPR 10090 && negate_expr_p (arg0)) 10091 { 10092 if (INTEGRAL_TYPE_P (type)) 10093 fold_overflow_warning (("assuming signed overflow does not occur " 10094 "when distributing negation across " 10095 "division"), 10096 WARN_STRICT_OVERFLOW_MISC); 10097 return fold_build2 (code, type, negate_expr (arg0), 10098 TREE_OPERAND (arg1, 0)); 10099 } 10100 10101 /* If arg0 is a multiple of arg1, then rewrite to the fastest div 10102 operation, EXACT_DIV_EXPR. 10103 10104 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now. 10105 At one time others generated faster code, it's not clear if they do 10106 after the last round to changes to the DIV code in expmed.c. */ 10107 if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR) 10108 && multiple_of_p (type, arg0, arg1)) 10109 return fold_build2 (EXACT_DIV_EXPR, type, arg0, arg1); 10110 10111 strict_overflow_p = false; 10112 if (TREE_CODE (arg1) == INTEGER_CST 10113 && 0 != (tem = extract_muldiv (op0, arg1, code, NULL_TREE, 10114 &strict_overflow_p))) 10115 { 10116 if (strict_overflow_p) 10117 fold_overflow_warning (("assuming signed overflow does not occur " 10118 "when simplifying division"), 10119 WARN_STRICT_OVERFLOW_MISC); 10120 return fold_convert (type, tem); 10121 } 10122 10123 return NULL_TREE; 10124 10125 case CEIL_MOD_EXPR: 10126 case FLOOR_MOD_EXPR: 10127 case ROUND_MOD_EXPR: 10128 case TRUNC_MOD_EXPR: 10129 /* X % 1 is always zero, but be sure to preserve any side 10130 effects in X. */ 10131 if (integer_onep (arg1)) 10132 return omit_one_operand (type, integer_zero_node, arg0); 10133 10134 /* X % 0, return X % 0 unchanged so that we can get the 10135 proper warnings and errors. */ 10136 if (integer_zerop (arg1)) 10137 return NULL_TREE; 10138 10139 /* 0 % X is always zero, but be sure to preserve any side 10140 effects in X. Place this after checking for X == 0. */ 10141 if (integer_zerop (arg0)) 10142 return omit_one_operand (type, integer_zero_node, arg1); 10143 10144 /* X % -1 is zero. */ 10145 if (!TYPE_UNSIGNED (type) 10146 && TREE_CODE (arg1) == INTEGER_CST 10147 && TREE_INT_CST_LOW (arg1) == (unsigned HOST_WIDE_INT) -1 10148 && TREE_INT_CST_HIGH (arg1) == -1) 10149 return omit_one_operand (type, integer_zero_node, arg0); 10150 10151 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR, 10152 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */ 10153 strict_overflow_p = false; 10154 if ((code == TRUNC_MOD_EXPR || code == FLOOR_MOD_EXPR) 10155 && (TYPE_UNSIGNED (type) 10156 || tree_expr_nonnegative_warnv_p (arg0, &strict_overflow_p))) 10157 { 10158 tree c = arg1; 10159 /* Also optimize A % (C << N) where C is a power of 2, 10160 to A & ((C << N) - 1). */ 10161 if (TREE_CODE (arg1) == LSHIFT_EXPR) 10162 c = TREE_OPERAND (arg1, 0); 10163 10164 if (integer_pow2p (c) && tree_int_cst_sgn (c) > 0) 10165 { 10166 tree mask = fold_build2 (MINUS_EXPR, TREE_TYPE (arg1), 10167 arg1, integer_one_node); 10168 if (strict_overflow_p) 10169 fold_overflow_warning (("assuming signed overflow does not " 10170 "occur when simplifying " 10171 "X % (power of two)"), 10172 WARN_STRICT_OVERFLOW_MISC); 10173 return fold_build2 (BIT_AND_EXPR, type, 10174 fold_convert (type, arg0), 10175 fold_convert (type, mask)); 10176 } 10177 } 10178 10179 /* X % -C is the same as X % C. */ 10180 if (code == TRUNC_MOD_EXPR 10181 && !TYPE_UNSIGNED (type) 10182 && TREE_CODE (arg1) == INTEGER_CST 10183 && !TREE_CONSTANT_OVERFLOW (arg1) 10184 && TREE_INT_CST_HIGH (arg1) < 0 10185 && !TYPE_OVERFLOW_TRAPS (type) 10186 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */ 10187 && !sign_bit_p (arg1, arg1)) 10188 return fold_build2 (code, type, fold_convert (type, arg0), 10189 fold_convert (type, negate_expr (arg1))); 10190 10191 /* X % -Y is the same as X % Y. */ 10192 if (code == TRUNC_MOD_EXPR 10193 && !TYPE_UNSIGNED (type) 10194 && TREE_CODE (arg1) == NEGATE_EXPR 10195 && !TYPE_OVERFLOW_TRAPS (type)) 10196 return fold_build2 (code, type, fold_convert (type, arg0), 10197 fold_convert (type, TREE_OPERAND (arg1, 0))); 10198 10199 if (TREE_CODE (arg1) == INTEGER_CST 10200 && 0 != (tem = extract_muldiv (op0, arg1, code, NULL_TREE, 10201 &strict_overflow_p))) 10202 { 10203 if (strict_overflow_p) 10204 fold_overflow_warning (("assuming signed overflow does not occur " 10205 "when simplifying modulos"), 10206 WARN_STRICT_OVERFLOW_MISC); 10207 return fold_convert (type, tem); 10208 } 10209 10210 return NULL_TREE; 10211 10212 case LROTATE_EXPR: 10213 case RROTATE_EXPR: 10214 if (integer_all_onesp (arg0)) 10215 return omit_one_operand (type, arg0, arg1); 10216 goto shift; 10217 10218 case RSHIFT_EXPR: 10219 /* Optimize -1 >> x for arithmetic right shifts. */ 10220 if (integer_all_onesp (arg0) && !TYPE_UNSIGNED (type)) 10221 return omit_one_operand (type, arg0, arg1); 10222 /* ... fall through ... */ 10223 10224 case LSHIFT_EXPR: 10225 shift: 10226 if (integer_zerop (arg1)) 10227 return non_lvalue (fold_convert (type, arg0)); 10228 if (integer_zerop (arg0)) 10229 return omit_one_operand (type, arg0, arg1); 10230 10231 /* Since negative shift count is not well-defined, 10232 don't try to compute it in the compiler. */ 10233 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0) 10234 return NULL_TREE; 10235 10236 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */ 10237 if (TREE_CODE (op0) == code && host_integerp (arg1, false) 10238 && TREE_INT_CST_LOW (arg1) < TYPE_PRECISION (type) 10239 && host_integerp (TREE_OPERAND (arg0, 1), false) 10240 && TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) < TYPE_PRECISION (type)) 10241 { 10242 HOST_WIDE_INT low = (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) 10243 + TREE_INT_CST_LOW (arg1)); 10244 10245 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2 10246 being well defined. */ 10247 if (low >= TYPE_PRECISION (type)) 10248 { 10249 if (code == LROTATE_EXPR || code == RROTATE_EXPR) 10250 low = low % TYPE_PRECISION (type); 10251 else if (TYPE_UNSIGNED (type) || code == LSHIFT_EXPR) 10252 return build_int_cst (type, 0); 10253 else 10254 low = TYPE_PRECISION (type) - 1; 10255 } 10256 10257 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), 10258 build_int_cst (type, low)); 10259 } 10260 10261 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c 10262 into x & ((unsigned)-1 >> c) for unsigned types. */ 10263 if (((code == LSHIFT_EXPR && TREE_CODE (arg0) == RSHIFT_EXPR) 10264 || (TYPE_UNSIGNED (type) 10265 && code == RSHIFT_EXPR && TREE_CODE (arg0) == LSHIFT_EXPR)) 10266 && host_integerp (arg1, false) 10267 && TREE_INT_CST_LOW (arg1) < TYPE_PRECISION (type) 10268 && host_integerp (TREE_OPERAND (arg0, 1), false) 10269 && TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) < TYPE_PRECISION (type)) 10270 { 10271 HOST_WIDE_INT low0 = TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)); 10272 HOST_WIDE_INT low1 = TREE_INT_CST_LOW (arg1); 10273 tree lshift; 10274 tree arg00; 10275 10276 if (low0 == low1) 10277 { 10278 arg00 = fold_convert (type, TREE_OPERAND (arg0, 0)); 10279 10280 lshift = build_int_cst (type, -1); 10281 lshift = int_const_binop (code, lshift, arg1, 0); 10282 10283 return fold_build2 (BIT_AND_EXPR, type, arg00, lshift); 10284 } 10285 } 10286 10287 /* Rewrite an LROTATE_EXPR by a constant into an 10288 RROTATE_EXPR by a new constant. */ 10289 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST) 10290 { 10291 tree tem = build_int_cst (NULL_TREE, 10292 GET_MODE_BITSIZE (TYPE_MODE (type))); 10293 tem = fold_convert (TREE_TYPE (arg1), tem); 10294 tem = const_binop (MINUS_EXPR, tem, arg1, 0); 10295 return fold_build2 (RROTATE_EXPR, type, arg0, tem); 10296 } 10297 10298 /* If we have a rotate of a bit operation with the rotate count and 10299 the second operand of the bit operation both constant, 10300 permute the two operations. */ 10301 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST 10302 && (TREE_CODE (arg0) == BIT_AND_EXPR 10303 || TREE_CODE (arg0) == BIT_IOR_EXPR 10304 || TREE_CODE (arg0) == BIT_XOR_EXPR) 10305 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) 10306 return fold_build2 (TREE_CODE (arg0), type, 10307 fold_build2 (code, type, 10308 TREE_OPERAND (arg0, 0), arg1), 10309 fold_build2 (code, type, 10310 TREE_OPERAND (arg0, 1), arg1)); 10311 10312 /* Two consecutive rotates adding up to the width of the mode can 10313 be ignored. */ 10314 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST 10315 && TREE_CODE (arg0) == RROTATE_EXPR 10316 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST 10317 && TREE_INT_CST_HIGH (arg1) == 0 10318 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0 10319 && ((TREE_INT_CST_LOW (arg1) 10320 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1))) 10321 == (unsigned int) GET_MODE_BITSIZE (TYPE_MODE (type)))) 10322 return TREE_OPERAND (arg0, 0); 10323 10324 return NULL_TREE; 10325 10326 case MIN_EXPR: 10327 if (operand_equal_p (arg0, arg1, 0)) 10328 return omit_one_operand (type, arg0, arg1); 10329 if (INTEGRAL_TYPE_P (type) 10330 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), OEP_ONLY_CONST)) 10331 return omit_one_operand (type, arg1, arg0); 10332 tem = fold_minmax (MIN_EXPR, type, arg0, arg1); 10333 if (tem) 10334 return tem; 10335 goto associate; 10336 10337 case MAX_EXPR: 10338 if (operand_equal_p (arg0, arg1, 0)) 10339 return omit_one_operand (type, arg0, arg1); 10340 if (INTEGRAL_TYPE_P (type) 10341 && TYPE_MAX_VALUE (type) 10342 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), OEP_ONLY_CONST)) 10343 return omit_one_operand (type, arg1, arg0); 10344 tem = fold_minmax (MAX_EXPR, type, arg0, arg1); 10345 if (tem) 10346 return tem; 10347 goto associate; 10348 10349 case TRUTH_ANDIF_EXPR: 10350 /* Note that the operands of this must be ints 10351 and their values must be 0 or 1. 10352 ("true" is a fixed value perhaps depending on the language.) */ 10353 /* If first arg is constant zero, return it. */ 10354 if (integer_zerop (arg0)) 10355 return fold_convert (type, arg0); 10356 case TRUTH_AND_EXPR: 10357 /* If either arg is constant true, drop it. */ 10358 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) 10359 return non_lvalue (fold_convert (type, arg1)); 10360 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1) 10361 /* Preserve sequence points. */ 10362 && (code != TRUTH_ANDIF_EXPR || ! TREE_SIDE_EFFECTS (arg0))) 10363 return non_lvalue (fold_convert (type, arg0)); 10364 /* If second arg is constant zero, result is zero, but first arg 10365 must be evaluated. */ 10366 if (integer_zerop (arg1)) 10367 return omit_one_operand (type, arg1, arg0); 10368 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR 10369 case will be handled here. */ 10370 if (integer_zerop (arg0)) 10371 return omit_one_operand (type, arg0, arg1); 10372 10373 /* !X && X is always false. */ 10374 if (TREE_CODE (arg0) == TRUTH_NOT_EXPR 10375 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) 10376 return omit_one_operand (type, integer_zero_node, arg1); 10377 /* X && !X is always false. */ 10378 if (TREE_CODE (arg1) == TRUTH_NOT_EXPR 10379 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 10380 return omit_one_operand (type, integer_zero_node, arg0); 10381 10382 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y 10383 means A >= Y && A != MAX, but in this case we know that 10384 A < X <= MAX. */ 10385 10386 if (!TREE_SIDE_EFFECTS (arg0) 10387 && !TREE_SIDE_EFFECTS (arg1)) 10388 { 10389 tem = fold_to_nonsharp_ineq_using_bound (arg0, arg1); 10390 if (tem && !operand_equal_p (tem, arg0, 0)) 10391 return fold_build2 (code, type, tem, arg1); 10392 10393 tem = fold_to_nonsharp_ineq_using_bound (arg1, arg0); 10394 if (tem && !operand_equal_p (tem, arg1, 0)) 10395 return fold_build2 (code, type, arg0, tem); 10396 } 10397 10398 truth_andor: 10399 /* We only do these simplifications if we are optimizing. */ 10400 if (!optimize) 10401 return NULL_TREE; 10402 10403 /* Check for things like (A || B) && (A || C). We can convert this 10404 to A || (B && C). Note that either operator can be any of the four 10405 truth and/or operations and the transformation will still be 10406 valid. Also note that we only care about order for the 10407 ANDIF and ORIF operators. If B contains side effects, this 10408 might change the truth-value of A. */ 10409 if (TREE_CODE (arg0) == TREE_CODE (arg1) 10410 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR 10411 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR 10412 || TREE_CODE (arg0) == TRUTH_AND_EXPR 10413 || TREE_CODE (arg0) == TRUTH_OR_EXPR) 10414 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1))) 10415 { 10416 tree a00 = TREE_OPERAND (arg0, 0); 10417 tree a01 = TREE_OPERAND (arg0, 1); 10418 tree a10 = TREE_OPERAND (arg1, 0); 10419 tree a11 = TREE_OPERAND (arg1, 1); 10420 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR 10421 || TREE_CODE (arg0) == TRUTH_AND_EXPR) 10422 && (code == TRUTH_AND_EXPR 10423 || code == TRUTH_OR_EXPR)); 10424 10425 if (operand_equal_p (a00, a10, 0)) 10426 return fold_build2 (TREE_CODE (arg0), type, a00, 10427 fold_build2 (code, type, a01, a11)); 10428 else if (commutative && operand_equal_p (a00, a11, 0)) 10429 return fold_build2 (TREE_CODE (arg0), type, a00, 10430 fold_build2 (code, type, a01, a10)); 10431 else if (commutative && operand_equal_p (a01, a10, 0)) 10432 return fold_build2 (TREE_CODE (arg0), type, a01, 10433 fold_build2 (code, type, a00, a11)); 10434 10435 /* This case if tricky because we must either have commutative 10436 operators or else A10 must not have side-effects. */ 10437 10438 else if ((commutative || ! TREE_SIDE_EFFECTS (a10)) 10439 && operand_equal_p (a01, a11, 0)) 10440 return fold_build2 (TREE_CODE (arg0), type, 10441 fold_build2 (code, type, a00, a10), 10442 a01); 10443 } 10444 10445 /* See if we can build a range comparison. */ 10446 if (0 != (tem = fold_range_test (code, type, op0, op1))) 10447 return tem; 10448 10449 /* Check for the possibility of merging component references. If our 10450 lhs is another similar operation, try to merge its rhs with our 10451 rhs. Then try to merge our lhs and rhs. */ 10452 if (TREE_CODE (arg0) == code 10453 && 0 != (tem = fold_truthop (code, type, 10454 TREE_OPERAND (arg0, 1), arg1))) 10455 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), tem); 10456 10457 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0) 10458 return tem; 10459 10460 return NULL_TREE; 10461 10462 case TRUTH_ORIF_EXPR: 10463 /* Note that the operands of this must be ints 10464 and their values must be 0 or true. 10465 ("true" is a fixed value perhaps depending on the language.) */ 10466 /* If first arg is constant true, return it. */ 10467 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) 10468 return fold_convert (type, arg0); 10469 case TRUTH_OR_EXPR: 10470 /* If either arg is constant zero, drop it. */ 10471 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0)) 10472 return non_lvalue (fold_convert (type, arg1)); 10473 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1) 10474 /* Preserve sequence points. */ 10475 && (code != TRUTH_ORIF_EXPR || ! TREE_SIDE_EFFECTS (arg0))) 10476 return non_lvalue (fold_convert (type, arg0)); 10477 /* If second arg is constant true, result is true, but we must 10478 evaluate first arg. */ 10479 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)) 10480 return omit_one_operand (type, arg1, arg0); 10481 /* Likewise for first arg, but note this only occurs here for 10482 TRUTH_OR_EXPR. */ 10483 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) 10484 return omit_one_operand (type, arg0, arg1); 10485 10486 /* !X || X is always true. */ 10487 if (TREE_CODE (arg0) == TRUTH_NOT_EXPR 10488 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) 10489 return omit_one_operand (type, integer_one_node, arg1); 10490 /* X || !X is always true. */ 10491 if (TREE_CODE (arg1) == TRUTH_NOT_EXPR 10492 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 10493 return omit_one_operand (type, integer_one_node, arg0); 10494 10495 goto truth_andor; 10496 10497 case TRUTH_XOR_EXPR: 10498 /* If the second arg is constant zero, drop it. */ 10499 if (integer_zerop (arg1)) 10500 return non_lvalue (fold_convert (type, arg0)); 10501 /* If the second arg is constant true, this is a logical inversion. */ 10502 if (integer_onep (arg1)) 10503 { 10504 /* Only call invert_truthvalue if operand is a truth value. */ 10505 if (TREE_CODE (TREE_TYPE (arg0)) != BOOLEAN_TYPE) 10506 tem = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (arg0), arg0); 10507 else 10508 tem = invert_truthvalue (arg0); 10509 return non_lvalue (fold_convert (type, tem)); 10510 } 10511 /* Identical arguments cancel to zero. */ 10512 if (operand_equal_p (arg0, arg1, 0)) 10513 return omit_one_operand (type, integer_zero_node, arg0); 10514 10515 /* !X ^ X is always true. */ 10516 if (TREE_CODE (arg0) == TRUTH_NOT_EXPR 10517 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) 10518 return omit_one_operand (type, integer_one_node, arg1); 10519 10520 /* X ^ !X is always true. */ 10521 if (TREE_CODE (arg1) == TRUTH_NOT_EXPR 10522 && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) 10523 return omit_one_operand (type, integer_one_node, arg0); 10524 10525 return NULL_TREE; 10526 10527 case EQ_EXPR: 10528 case NE_EXPR: 10529 tem = fold_comparison (code, type, op0, op1); 10530 if (tem != NULL_TREE) 10531 return tem; 10532 10533 /* bool_var != 0 becomes bool_var. */ 10534 if (TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE && integer_zerop (arg1) 10535 && code == NE_EXPR) 10536 return non_lvalue (fold_convert (type, arg0)); 10537 10538 /* bool_var == 1 becomes bool_var. */ 10539 if (TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE && integer_onep (arg1) 10540 && code == EQ_EXPR) 10541 return non_lvalue (fold_convert (type, arg0)); 10542 10543 /* bool_var != 1 becomes !bool_var. */ 10544 if (TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE && integer_onep (arg1) 10545 && code == NE_EXPR) 10546 return fold_build1 (TRUTH_NOT_EXPR, type, arg0); 10547 10548 /* bool_var == 0 becomes !bool_var. */ 10549 if (TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE && integer_zerop (arg1) 10550 && code == EQ_EXPR) 10551 return fold_build1 (TRUTH_NOT_EXPR, type, arg0); 10552 10553 /* ~a != C becomes a != ~C where C is a constant. Likewise for ==. */ 10554 if (TREE_CODE (arg0) == BIT_NOT_EXPR 10555 && TREE_CODE (arg1) == INTEGER_CST) 10556 { 10557 tree cmp_type = TREE_TYPE (TREE_OPERAND (arg0, 0)); 10558 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), 10559 fold_build1 (BIT_NOT_EXPR, cmp_type, 10560 fold_convert (cmp_type, arg1))); 10561 } 10562 10563 /* If this is an equality comparison of the address of a non-weak 10564 object against zero, then we know the result. */ 10565 if (TREE_CODE (arg0) == ADDR_EXPR 10566 && VAR_OR_FUNCTION_DECL_P (TREE_OPERAND (arg0, 0)) 10567 && ! DECL_WEAK (TREE_OPERAND (arg0, 0)) 10568 && integer_zerop (arg1)) 10569 return constant_boolean_node (code != EQ_EXPR, type); 10570 10571 /* If this is an equality comparison of the address of two non-weak, 10572 unaliased symbols neither of which are extern (since we do not 10573 have access to attributes for externs), then we know the result. */ 10574 if (TREE_CODE (arg0) == ADDR_EXPR 10575 && VAR_OR_FUNCTION_DECL_P (TREE_OPERAND (arg0, 0)) 10576 && ! DECL_WEAK (TREE_OPERAND (arg0, 0)) 10577 && ! lookup_attribute ("alias", 10578 DECL_ATTRIBUTES (TREE_OPERAND (arg0, 0))) 10579 && ! DECL_EXTERNAL (TREE_OPERAND (arg0, 0)) 10580 && TREE_CODE (arg1) == ADDR_EXPR 10581 && VAR_OR_FUNCTION_DECL_P (TREE_OPERAND (arg1, 0)) 10582 && ! DECL_WEAK (TREE_OPERAND (arg1, 0)) 10583 && ! lookup_attribute ("alias", 10584 DECL_ATTRIBUTES (TREE_OPERAND (arg1, 0))) 10585 && ! DECL_EXTERNAL (TREE_OPERAND (arg1, 0))) 10586 { 10587 /* We know that we're looking at the address of two 10588 non-weak, unaliased, static _DECL nodes. 10589 10590 It is both wasteful and incorrect to call operand_equal_p 10591 to compare the two ADDR_EXPR nodes. It is wasteful in that 10592 all we need to do is test pointer equality for the arguments 10593 to the two ADDR_EXPR nodes. It is incorrect to use 10594 operand_equal_p as that function is NOT equivalent to a 10595 C equality test. It can in fact return false for two 10596 objects which would test as equal using the C equality 10597 operator. */ 10598 bool equal = TREE_OPERAND (arg0, 0) == TREE_OPERAND (arg1, 0); 10599 return constant_boolean_node (equal 10600 ? code == EQ_EXPR : code != EQ_EXPR, 10601 type); 10602 } 10603 10604 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or 10605 a MINUS_EXPR of a constant, we can convert it into a comparison with 10606 a revised constant as long as no overflow occurs. */ 10607 if (TREE_CODE (arg1) == INTEGER_CST 10608 && (TREE_CODE (arg0) == PLUS_EXPR 10609 || TREE_CODE (arg0) == MINUS_EXPR) 10610 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST 10611 && 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR 10612 ? MINUS_EXPR : PLUS_EXPR, 10613 fold_convert (TREE_TYPE (arg0), arg1), 10614 TREE_OPERAND (arg0, 1), 0)) 10615 && ! TREE_CONSTANT_OVERFLOW (tem)) 10616 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), tem); 10617 10618 /* Similarly for a NEGATE_EXPR. */ 10619 if (TREE_CODE (arg0) == NEGATE_EXPR 10620 && TREE_CODE (arg1) == INTEGER_CST 10621 && 0 != (tem = negate_expr (arg1)) 10622 && TREE_CODE (tem) == INTEGER_CST 10623 && ! TREE_CONSTANT_OVERFLOW (tem)) 10624 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), tem); 10625 10626 /* If we have X - Y == 0, we can convert that to X == Y and similarly 10627 for !=. Don't do this for ordered comparisons due to overflow. */ 10628 if (TREE_CODE (arg0) == MINUS_EXPR 10629 && integer_zerop (arg1)) 10630 return fold_build2 (code, type, 10631 TREE_OPERAND (arg0, 0), TREE_OPERAND (arg0, 1)); 10632 10633 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */ 10634 if (TREE_CODE (arg0) == ABS_EXPR 10635 && (integer_zerop (arg1) || real_zerop (arg1))) 10636 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), arg1); 10637 10638 /* If this is an EQ or NE comparison with zero and ARG0 is 10639 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require 10640 two operations, but the latter can be done in one less insn 10641 on machines that have only two-operand insns or on which a 10642 constant cannot be the first operand. */ 10643 if (TREE_CODE (arg0) == BIT_AND_EXPR 10644 && integer_zerop (arg1)) 10645 { 10646 tree arg00 = TREE_OPERAND (arg0, 0); 10647 tree arg01 = TREE_OPERAND (arg0, 1); 10648 if (TREE_CODE (arg00) == LSHIFT_EXPR 10649 && integer_onep (TREE_OPERAND (arg00, 0))) 10650 return 10651 fold_build2 (code, type, 10652 build2 (BIT_AND_EXPR, TREE_TYPE (arg0), 10653 build2 (RSHIFT_EXPR, TREE_TYPE (arg00), 10654 arg01, TREE_OPERAND (arg00, 1)), 10655 fold_convert (TREE_TYPE (arg0), 10656 integer_one_node)), 10657 arg1); 10658 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR 10659 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0))) 10660 return 10661 fold_build2 (code, type, 10662 build2 (BIT_AND_EXPR, TREE_TYPE (arg0), 10663 build2 (RSHIFT_EXPR, TREE_TYPE (arg01), 10664 arg00, TREE_OPERAND (arg01, 1)), 10665 fold_convert (TREE_TYPE (arg0), 10666 integer_one_node)), 10667 arg1); 10668 } 10669 10670 /* If this is an NE or EQ comparison of zero against the result of a 10671 signed MOD operation whose second operand is a power of 2, make 10672 the MOD operation unsigned since it is simpler and equivalent. */ 10673 if (integer_zerop (arg1) 10674 && !TYPE_UNSIGNED (TREE_TYPE (arg0)) 10675 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR 10676 || TREE_CODE (arg0) == CEIL_MOD_EXPR 10677 || TREE_CODE (arg0) == FLOOR_MOD_EXPR 10678 || TREE_CODE (arg0) == ROUND_MOD_EXPR) 10679 && integer_pow2p (TREE_OPERAND (arg0, 1))) 10680 { 10681 tree newtype = lang_hooks.types.unsigned_type (TREE_TYPE (arg0)); 10682 tree newmod = fold_build2 (TREE_CODE (arg0), newtype, 10683 fold_convert (newtype, 10684 TREE_OPERAND (arg0, 0)), 10685 fold_convert (newtype, 10686 TREE_OPERAND (arg0, 1))); 10687 10688 return fold_build2 (code, type, newmod, 10689 fold_convert (newtype, arg1)); 10690 } 10691 10692 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where 10693 C1 is a valid shift constant, and C2 is a power of two, i.e. 10694 a single bit. */ 10695 if (TREE_CODE (arg0) == BIT_AND_EXPR 10696 && TREE_CODE (TREE_OPERAND (arg0, 0)) == RSHIFT_EXPR 10697 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)) 10698 == INTEGER_CST 10699 && integer_pow2p (TREE_OPERAND (arg0, 1)) 10700 && integer_zerop (arg1)) 10701 { 10702 tree itype = TREE_TYPE (arg0); 10703 unsigned HOST_WIDE_INT prec = TYPE_PRECISION (itype); 10704 tree arg001 = TREE_OPERAND (TREE_OPERAND (arg0, 0), 1); 10705 10706 /* Check for a valid shift count. */ 10707 if (TREE_INT_CST_HIGH (arg001) == 0 10708 && TREE_INT_CST_LOW (arg001) < prec) 10709 { 10710 tree arg01 = TREE_OPERAND (arg0, 1); 10711 tree arg000 = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0); 10712 unsigned HOST_WIDE_INT log2 = tree_log2 (arg01); 10713 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0 10714 can be rewritten as (X & (C2 << C1)) != 0. */ 10715 if ((log2 + TREE_INT_CST_LOW (arg001)) < prec) 10716 { 10717 tem = fold_build2 (LSHIFT_EXPR, itype, arg01, arg001); 10718 tem = fold_build2 (BIT_AND_EXPR, itype, arg000, tem); 10719 return fold_build2 (code, type, tem, arg1); 10720 } 10721 /* Otherwise, for signed (arithmetic) shifts, 10722 ((X >> C1) & C2) != 0 is rewritten as X < 0, and 10723 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */ 10724 else if (!TYPE_UNSIGNED (itype)) 10725 return fold_build2 (code == EQ_EXPR ? GE_EXPR : LT_EXPR, type, 10726 arg000, build_int_cst (itype, 0)); 10727 /* Otherwise, of unsigned (logical) shifts, 10728 ((X >> C1) & C2) != 0 is rewritten as (X,false), and 10729 ((X >> C1) & C2) == 0 is rewritten as (X,true). */ 10730 else 10731 return omit_one_operand (type, 10732 code == EQ_EXPR ? integer_one_node 10733 : integer_zero_node, 10734 arg000); 10735 } 10736 } 10737 10738 /* If this is an NE comparison of zero with an AND of one, remove the 10739 comparison since the AND will give the correct value. */ 10740 if (code == NE_EXPR 10741 && integer_zerop (arg1) 10742 && TREE_CODE (arg0) == BIT_AND_EXPR 10743 && integer_onep (TREE_OPERAND (arg0, 1))) 10744 return fold_convert (type, arg0); 10745 10746 /* If we have (A & C) == C where C is a power of 2, convert this into 10747 (A & C) != 0. Similarly for NE_EXPR. */ 10748 if (TREE_CODE (arg0) == BIT_AND_EXPR 10749 && integer_pow2p (TREE_OPERAND (arg0, 1)) 10750 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) 10751 return fold_build2 (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type, 10752 arg0, fold_convert (TREE_TYPE (arg0), 10753 integer_zero_node)); 10754 10755 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign 10756 bit, then fold the expression into A < 0 or A >= 0. */ 10757 tem = fold_single_bit_test_into_sign_test (code, arg0, arg1, type); 10758 if (tem) 10759 return tem; 10760 10761 /* If we have (A & C) == D where D & ~C != 0, convert this into 0. 10762 Similarly for NE_EXPR. */ 10763 if (TREE_CODE (arg0) == BIT_AND_EXPR 10764 && TREE_CODE (arg1) == INTEGER_CST 10765 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) 10766 { 10767 tree notc = fold_build1 (BIT_NOT_EXPR, 10768 TREE_TYPE (TREE_OPERAND (arg0, 1)), 10769 TREE_OPERAND (arg0, 1)); 10770 tree dandnotc = fold_build2 (BIT_AND_EXPR, TREE_TYPE (arg0), 10771 arg1, notc); 10772 tree rslt = code == EQ_EXPR ? integer_zero_node : integer_one_node; 10773 if (integer_nonzerop (dandnotc)) 10774 return omit_one_operand (type, rslt, arg0); 10775 } 10776 10777 /* If we have (A | C) == D where C & ~D != 0, convert this into 0. 10778 Similarly for NE_EXPR. */ 10779 if (TREE_CODE (arg0) == BIT_IOR_EXPR 10780 && TREE_CODE (arg1) == INTEGER_CST 10781 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) 10782 { 10783 tree notd = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (arg1), arg1); 10784 tree candnotd = fold_build2 (BIT_AND_EXPR, TREE_TYPE (arg0), 10785 TREE_OPERAND (arg0, 1), notd); 10786 tree rslt = code == EQ_EXPR ? integer_zero_node : integer_one_node; 10787 if (integer_nonzerop (candnotd)) 10788 return omit_one_operand (type, rslt, arg0); 10789 } 10790 10791 /* If this is a comparison of a field, we may be able to simplify it. */ 10792 if (((TREE_CODE (arg0) == COMPONENT_REF 10793 && lang_hooks.can_use_bit_fields_p ()) 10794 || TREE_CODE (arg0) == BIT_FIELD_REF) 10795 /* Handle the constant case even without -O 10796 to make sure the warnings are given. */ 10797 && (optimize || TREE_CODE (arg1) == INTEGER_CST)) 10798 { 10799 t1 = optimize_bit_field_compare (code, type, arg0, arg1); 10800 if (t1) 10801 return t1; 10802 } 10803 10804 /* Optimize comparisons of strlen vs zero to a compare of the 10805 first character of the string vs zero. To wit, 10806 strlen(ptr) == 0 => *ptr == 0 10807 strlen(ptr) != 0 => *ptr != 0 10808 Other cases should reduce to one of these two (or a constant) 10809 due to the return value of strlen being unsigned. */ 10810 if (TREE_CODE (arg0) == CALL_EXPR 10811 && integer_zerop (arg1)) 10812 { 10813 tree fndecl = get_callee_fndecl (arg0); 10814 tree arglist; 10815 10816 if (fndecl 10817 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL 10818 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STRLEN 10819 && (arglist = TREE_OPERAND (arg0, 1)) 10820 && TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) == POINTER_TYPE 10821 && ! TREE_CHAIN (arglist)) 10822 { 10823 tree iref = build_fold_indirect_ref (TREE_VALUE (arglist)); 10824 return fold_build2 (code, type, iref, 10825 build_int_cst (TREE_TYPE (iref), 0)); 10826 } 10827 } 10828 10829 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width 10830 of X. Similarly fold (X >> C) == 0 into X >= 0. */ 10831 if (TREE_CODE (arg0) == RSHIFT_EXPR 10832 && integer_zerop (arg1) 10833 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) 10834 { 10835 tree arg00 = TREE_OPERAND (arg0, 0); 10836 tree arg01 = TREE_OPERAND (arg0, 1); 10837 tree itype = TREE_TYPE (arg00); 10838 if (TREE_INT_CST_HIGH (arg01) == 0 10839 && TREE_INT_CST_LOW (arg01) 10840 == (unsigned HOST_WIDE_INT) (TYPE_PRECISION (itype) - 1)) 10841 { 10842 if (TYPE_UNSIGNED (itype)) 10843 { 10844 itype = lang_hooks.types.signed_type (itype); 10845 arg00 = fold_convert (itype, arg00); 10846 } 10847 return fold_build2 (code == EQ_EXPR ? GE_EXPR : LT_EXPR, 10848 type, arg00, build_int_cst (itype, 0)); 10849 } 10850 } 10851 10852 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */ 10853 if (integer_zerop (arg1) 10854 && TREE_CODE (arg0) == BIT_XOR_EXPR) 10855 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), 10856 TREE_OPERAND (arg0, 1)); 10857 10858 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */ 10859 if (TREE_CODE (arg0) == BIT_XOR_EXPR 10860 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) 10861 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), 10862 build_int_cst (TREE_TYPE (arg1), 0)); 10863 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */ 10864 if (TREE_CODE (arg0) == BIT_XOR_EXPR 10865 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) 10866 && reorder_operands_p (TREE_OPERAND (arg0, 1), arg1)) 10867 return fold_build2 (code, type, TREE_OPERAND (arg0, 1), 10868 build_int_cst (TREE_TYPE (arg1), 0)); 10869 10870 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */ 10871 if (TREE_CODE (arg0) == BIT_XOR_EXPR 10872 && TREE_CODE (arg1) == INTEGER_CST 10873 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) 10874 return fold_build2 (code, type, TREE_OPERAND (arg0, 0), 10875 fold_build2 (BIT_XOR_EXPR, TREE_TYPE (arg1), 10876 TREE_OPERAND (arg0, 1), arg1)); 10877 10878 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into 10879 (X & C) == 0 when C is a single bit. */ 10880 if (TREE_CODE (arg0) == BIT_AND_EXPR 10881 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_NOT_EXPR 10882 && integer_zerop (arg1) 10883 && integer_pow2p (TREE_OPERAND (arg0, 1))) 10884 { 10885 tem = fold_build2 (BIT_AND_EXPR, TREE_TYPE (arg0), 10886 TREE_OPERAND (TREE_OPERAND (arg0, 0), 0), 10887 TREE_OPERAND (arg0, 1)); 10888 return fold_build2 (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, 10889 type, tem, arg1); 10890 } 10891 10892 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the 10893 constant C is a power of two, i.e. a single bit. */ 10894 if (TREE_CODE (arg0) == BIT_XOR_EXPR 10895 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR 10896 && integer_zerop (arg1) 10897 && integer_pow2p (TREE_OPERAND (arg0, 1)) 10898 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1), 10899 TREE_OPERAND (arg0, 1), OEP_ONLY_CONST)) 10900 { 10901 tree arg00 = TREE_OPERAND (arg0, 0); 10902 return fold_build2 (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type, 10903 arg00, build_int_cst (TREE_TYPE (arg00), 0)); 10904 } 10905 10906 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0, 10907 when is C is a power of two, i.e. a single bit. */ 10908 if (TREE_CODE (arg0) == BIT_AND_EXPR 10909 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_XOR_EXPR 10910 && integer_zerop (arg1) 10911 && integer_pow2p (TREE_OPERAND (arg0, 1)) 10912 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1), 10913 TREE_OPERAND (arg0, 1), OEP_ONLY_CONST)) 10914 { 10915 tree arg000 = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0); 10916 tem = fold_build2 (BIT_AND_EXPR, TREE_TYPE (arg000), 10917 arg000, TREE_OPERAND (arg0, 1)); 10918 return fold_build2 (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type, 10919 tem, build_int_cst (TREE_TYPE (tem), 0)); 10920 } 10921 10922 if (integer_zerop (arg1) 10923 && tree_expr_nonzero_p (arg0)) 10924 { 10925 tree res = constant_boolean_node (code==NE_EXPR, type); 10926 return omit_one_operand (type, res, arg0); 10927 } 10928 return NULL_TREE; 10929 10930 case LT_EXPR: 10931 case GT_EXPR: 10932 case LE_EXPR: 10933 case GE_EXPR: 10934 tem = fold_comparison (code, type, op0, op1); 10935 if (tem != NULL_TREE) 10936 return tem; 10937 10938 /* Transform comparisons of the form X +- C CMP X. */ 10939 if ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) 10940 && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) 10941 && ((TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST 10942 && !HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))) 10943 || (TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST 10944 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))))) 10945 { 10946 tree arg01 = TREE_OPERAND (arg0, 1); 10947 enum tree_code code0 = TREE_CODE (arg0); 10948 int is_positive; 10949 10950 if (TREE_CODE (arg01) == REAL_CST) 10951 is_positive = REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg01)) ? -1 : 1; 10952 else 10953 is_positive = tree_int_cst_sgn (arg01); 10954 10955 /* (X - c) > X becomes false. */ 10956 if (code == GT_EXPR 10957 && ((code0 == MINUS_EXPR && is_positive >= 0) 10958 || (code0 == PLUS_EXPR && is_positive <= 0))) 10959 { 10960 if (TREE_CODE (arg01) == INTEGER_CST 10961 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))) 10962 fold_overflow_warning (("assuming signed overflow does not " 10963 "occur when assuming that (X - c) > X " 10964 "is always false"), 10965 WARN_STRICT_OVERFLOW_ALL); 10966 return constant_boolean_node (0, type); 10967 } 10968 10969 /* Likewise (X + c) < X becomes false. */ 10970 if (code == LT_EXPR 10971 && ((code0 == PLUS_EXPR && is_positive >= 0) 10972 || (code0 == MINUS_EXPR && is_positive <= 0))) 10973 { 10974 if (TREE_CODE (arg01) == INTEGER_CST 10975 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))) 10976 fold_overflow_warning (("assuming signed overflow does not " 10977 "occur when assuming that " 10978 "(X + c) < X is always false"), 10979 WARN_STRICT_OVERFLOW_ALL); 10980 return constant_boolean_node (0, type); 10981 } 10982 10983 /* Convert (X - c) <= X to true. */ 10984 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1))) 10985 && code == LE_EXPR 10986 && ((code0 == MINUS_EXPR && is_positive >= 0) 10987 || (code0 == PLUS_EXPR && is_positive <= 0))) 10988 { 10989 if (TREE_CODE (arg01) == INTEGER_CST 10990 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))) 10991 fold_overflow_warning (("assuming signed overflow does not " 10992 "occur when assuming that " 10993 "(X - c) <= X is always true"), 10994 WARN_STRICT_OVERFLOW_ALL); 10995 return constant_boolean_node (1, type); 10996 } 10997 10998 /* Convert (X + c) >= X to true. */ 10999 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1))) 11000 && code == GE_EXPR 11001 && ((code0 == PLUS_EXPR && is_positive >= 0) 11002 || (code0 == MINUS_EXPR && is_positive <= 0))) 11003 { 11004 if (TREE_CODE (arg01) == INTEGER_CST 11005 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))) 11006 fold_overflow_warning (("assuming signed overflow does not " 11007 "occur when assuming that " 11008 "(X + c) >= X is always true"), 11009 WARN_STRICT_OVERFLOW_ALL); 11010 return constant_boolean_node (1, type); 11011 } 11012 11013 if (TREE_CODE (arg01) == INTEGER_CST) 11014 { 11015 /* Convert X + c > X and X - c < X to true for integers. */ 11016 if (code == GT_EXPR 11017 && ((code0 == PLUS_EXPR && is_positive > 0) 11018 || (code0 == MINUS_EXPR && is_positive < 0))) 11019 { 11020 if (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))) 11021 fold_overflow_warning (("assuming signed overflow does " 11022 "not occur when assuming that " 11023 "(X + c) > X is always true"), 11024 WARN_STRICT_OVERFLOW_ALL); 11025 return constant_boolean_node (1, type); 11026 } 11027 11028 if (code == LT_EXPR 11029 && ((code0 == MINUS_EXPR && is_positive > 0) 11030 || (code0 == PLUS_EXPR && is_positive < 0))) 11031 { 11032 if (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))) 11033 fold_overflow_warning (("assuming signed overflow does " 11034 "not occur when assuming that " 11035 "(X - c) < X is always true"), 11036 WARN_STRICT_OVERFLOW_ALL); 11037 return constant_boolean_node (1, type); 11038 } 11039 11040 /* Convert X + c <= X and X - c >= X to false for integers. */ 11041 if (code == LE_EXPR 11042 && ((code0 == PLUS_EXPR && is_positive > 0) 11043 || (code0 == MINUS_EXPR && is_positive < 0))) 11044 { 11045 if (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))) 11046 fold_overflow_warning (("assuming signed overflow does " 11047 "not occur when assuming that " 11048 "(X + c) <= X is always false"), 11049 WARN_STRICT_OVERFLOW_ALL); 11050 return constant_boolean_node (0, type); 11051 } 11052 11053 if (code == GE_EXPR 11054 && ((code0 == MINUS_EXPR && is_positive > 0) 11055 || (code0 == PLUS_EXPR && is_positive < 0))) 11056 { 11057 if (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg1))) 11058 fold_overflow_warning (("assuming signed overflow does " 11059 "not occur when assuming that " 11060 "(X - c) >= X is always true"), 11061 WARN_STRICT_OVERFLOW_ALL); 11062 return constant_boolean_node (0, type); 11063 } 11064 } 11065 } 11066 11067 /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0. 11068 This transformation affects the cases which are handled in later 11069 optimizations involving comparisons with non-negative constants. */ 11070 if (TREE_CODE (arg1) == INTEGER_CST 11071 && TREE_CODE (arg0) != INTEGER_CST 11072 && tree_int_cst_sgn (arg1) > 0) 11073 { 11074 if (code == GE_EXPR) 11075 { 11076 arg1 = const_binop (MINUS_EXPR, arg1, 11077 build_int_cst (TREE_TYPE (arg1), 1), 0); 11078 return fold_build2 (GT_EXPR, type, arg0, 11079 fold_convert (TREE_TYPE (arg0), arg1)); 11080 } 11081 if (code == LT_EXPR) 11082 { 11083 arg1 = const_binop (MINUS_EXPR, arg1, 11084 build_int_cst (TREE_TYPE (arg1), 1), 0); 11085 return fold_build2 (LE_EXPR, type, arg0, 11086 fold_convert (TREE_TYPE (arg0), arg1)); 11087 } 11088 } 11089 11090 /* Comparisons with the highest or lowest possible integer of 11091 the specified size will have known values. */ 11092 { 11093 int width = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (arg1))); 11094 11095 if (TREE_CODE (arg1) == INTEGER_CST 11096 && ! TREE_CONSTANT_OVERFLOW (arg1) 11097 && width <= 2 * HOST_BITS_PER_WIDE_INT 11098 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1)) 11099 || POINTER_TYPE_P (TREE_TYPE (arg1)))) 11100 { 11101 HOST_WIDE_INT signed_max_hi; 11102 unsigned HOST_WIDE_INT signed_max_lo; 11103 unsigned HOST_WIDE_INT max_hi, max_lo, min_hi, min_lo; 11104 11105 if (width <= HOST_BITS_PER_WIDE_INT) 11106 { 11107 signed_max_lo = ((unsigned HOST_WIDE_INT) 1 << (width - 1)) 11108 - 1; 11109 signed_max_hi = 0; 11110 max_hi = 0; 11111 11112 if (TYPE_UNSIGNED (TREE_TYPE (arg1))) 11113 { 11114 max_lo = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1; 11115 min_lo = 0; 11116 min_hi = 0; 11117 } 11118 else 11119 { 11120 max_lo = signed_max_lo; 11121 min_lo = ((unsigned HOST_WIDE_INT) -1 << (width - 1)); 11122 min_hi = -1; 11123 } 11124 } 11125 else 11126 { 11127 width -= HOST_BITS_PER_WIDE_INT; 11128 signed_max_lo = -1; 11129 signed_max_hi = ((unsigned HOST_WIDE_INT) 1 << (width - 1)) 11130 - 1; 11131 max_lo = -1; 11132 min_lo = 0; 11133 11134 if (TYPE_UNSIGNED (TREE_TYPE (arg1))) 11135 { 11136 max_hi = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1; 11137 min_hi = 0; 11138 } 11139 else 11140 { 11141 max_hi = signed_max_hi; 11142 min_hi = ((unsigned HOST_WIDE_INT) -1 << (width - 1)); 11143 } 11144 } 11145 11146 if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1) == max_hi 11147 && TREE_INT_CST_LOW (arg1) == max_lo) 11148 switch (code) 11149 { 11150 case GT_EXPR: 11151 return omit_one_operand (type, integer_zero_node, arg0); 11152 11153 case GE_EXPR: 11154 return fold_build2 (EQ_EXPR, type, op0, op1); 11155 11156 case LE_EXPR: 11157 return omit_one_operand (type, integer_one_node, arg0); 11158 11159 case LT_EXPR: 11160 return fold_build2 (NE_EXPR, type, op0, op1); 11161 11162 /* The GE_EXPR and LT_EXPR cases above are not normally 11163 reached because of previous transformations. */ 11164 11165 default: 11166 break; 11167 } 11168 else if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1) 11169 == max_hi 11170 && TREE_INT_CST_LOW (arg1) == max_lo - 1) 11171 switch (code) 11172 { 11173 case GT_EXPR: 11174 arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0); 11175 return fold_build2 (EQ_EXPR, type, 11176 fold_convert (TREE_TYPE (arg1), arg0), 11177 arg1); 11178 case LE_EXPR: 11179 arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0); 11180 return fold_build2 (NE_EXPR, type, 11181 fold_convert (TREE_TYPE (arg1), arg0), 11182 arg1); 11183 default: 11184 break; 11185 } 11186 else if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1) 11187 == min_hi 11188 && TREE_INT_CST_LOW (arg1) == min_lo) 11189 switch (code) 11190 { 11191 case LT_EXPR: 11192 return omit_one_operand (type, integer_zero_node, arg0); 11193 11194 case LE_EXPR: 11195 return fold_build2 (EQ_EXPR, type, op0, op1); 11196 11197 case GE_EXPR: 11198 return omit_one_operand (type, integer_one_node, arg0); 11199 11200 case GT_EXPR: 11201 return fold_build2 (NE_EXPR, type, op0, op1); 11202 11203 default: 11204 break; 11205 } 11206 else if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1) 11207 == min_hi 11208 && TREE_INT_CST_LOW (arg1) == min_lo + 1) 11209 switch (code) 11210 { 11211 case GE_EXPR: 11212 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0); 11213 return fold_build2 (NE_EXPR, type, 11214 fold_convert (TREE_TYPE (arg1), arg0), 11215 arg1); 11216 case LT_EXPR: 11217 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0); 11218 return fold_build2 (EQ_EXPR, type, 11219 fold_convert (TREE_TYPE (arg1), arg0), 11220 arg1); 11221 default: 11222 break; 11223 } 11224 11225 else if (!in_gimple_form 11226 && TREE_INT_CST_HIGH (arg1) == signed_max_hi 11227 && TREE_INT_CST_LOW (arg1) == signed_max_lo 11228 && TYPE_UNSIGNED (TREE_TYPE (arg1)) 11229 /* signed_type does not work on pointer types. */ 11230 && INTEGRAL_TYPE_P (TREE_TYPE (arg1))) 11231 { 11232 /* The following case also applies to X < signed_max+1 11233 and X >= signed_max+1 because previous transformations. */ 11234 if (code == LE_EXPR || code == GT_EXPR) 11235 { 11236 tree st; 11237 st = lang_hooks.types.signed_type (TREE_TYPE (arg1)); 11238 return fold_build2 (code == LE_EXPR ? GE_EXPR : LT_EXPR, 11239 type, fold_convert (st, arg0), 11240 build_int_cst (st, 0)); 11241 } 11242 } 11243 } 11244 } 11245 11246 /* If we are comparing an ABS_EXPR with a constant, we can 11247 convert all the cases into explicit comparisons, but they may 11248 well not be faster than doing the ABS and one comparison. 11249 But ABS (X) <= C is a range comparison, which becomes a subtraction 11250 and a comparison, and is probably faster. */ 11251 if (code == LE_EXPR 11252 && TREE_CODE (arg1) == INTEGER_CST 11253 && TREE_CODE (arg0) == ABS_EXPR 11254 && ! TREE_SIDE_EFFECTS (arg0) 11255 && (0 != (tem = negate_expr (arg1))) 11256 && TREE_CODE (tem) == INTEGER_CST 11257 && ! TREE_CONSTANT_OVERFLOW (tem)) 11258 return fold_build2 (TRUTH_ANDIF_EXPR, type, 11259 build2 (GE_EXPR, type, 11260 TREE_OPERAND (arg0, 0), tem), 11261 build2 (LE_EXPR, type, 11262 TREE_OPERAND (arg0, 0), arg1)); 11263 11264 /* Convert ABS_EXPR<x> >= 0 to true. */ 11265 strict_overflow_p = false; 11266 if (code == GE_EXPR 11267 && (integer_zerop (arg1) 11268 || (! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0))) 11269 && real_zerop (arg1))) 11270 && tree_expr_nonnegative_warnv_p (arg0, &strict_overflow_p)) 11271 { 11272 if (strict_overflow_p) 11273 fold_overflow_warning (("assuming signed overflow does not occur " 11274 "when simplifying comparison of " 11275 "absolute value and zero"), 11276 WARN_STRICT_OVERFLOW_CONDITIONAL); 11277 return omit_one_operand (type, integer_one_node, arg0); 11278 } 11279 11280 /* Convert ABS_EXPR<x> < 0 to false. */ 11281 strict_overflow_p = false; 11282 if (code == LT_EXPR 11283 && (integer_zerop (arg1) || real_zerop (arg1)) 11284 && tree_expr_nonnegative_warnv_p (arg0, &strict_overflow_p)) 11285 { 11286 if (strict_overflow_p) 11287 fold_overflow_warning (("assuming signed overflow does not occur " 11288 "when simplifying comparison of " 11289 "absolute value and zero"), 11290 WARN_STRICT_OVERFLOW_CONDITIONAL); 11291 return omit_one_operand (type, integer_zero_node, arg0); 11292 } 11293 11294 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0 11295 and similarly for >= into !=. */ 11296 if ((code == LT_EXPR || code == GE_EXPR) 11297 && TYPE_UNSIGNED (TREE_TYPE (arg0)) 11298 && TREE_CODE (arg1) == LSHIFT_EXPR 11299 && integer_onep (TREE_OPERAND (arg1, 0))) 11300 return build2 (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type, 11301 build2 (RSHIFT_EXPR, TREE_TYPE (arg0), arg0, 11302 TREE_OPERAND (arg1, 1)), 11303 build_int_cst (TREE_TYPE (arg0), 0)); 11304 11305 if ((code == LT_EXPR || code == GE_EXPR) 11306 && TYPE_UNSIGNED (TREE_TYPE (arg0)) 11307 && (TREE_CODE (arg1) == NOP_EXPR 11308 || TREE_CODE (arg1) == CONVERT_EXPR) 11309 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR 11310 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0))) 11311 return 11312 build2 (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type, 11313 fold_convert (TREE_TYPE (arg0), 11314 build2 (RSHIFT_EXPR, TREE_TYPE (arg0), arg0, 11315 TREE_OPERAND (TREE_OPERAND (arg1, 0), 11316 1))), 11317 build_int_cst (TREE_TYPE (arg0), 0)); 11318 11319 return NULL_TREE; 11320 11321 case UNORDERED_EXPR: 11322 case ORDERED_EXPR: 11323 case UNLT_EXPR: 11324 case UNLE_EXPR: 11325 case UNGT_EXPR: 11326 case UNGE_EXPR: 11327 case UNEQ_EXPR: 11328 case LTGT_EXPR: 11329 if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST) 11330 { 11331 t1 = fold_relational_const (code, type, arg0, arg1); 11332 if (t1 != NULL_TREE) 11333 return t1; 11334 } 11335 11336 /* If the first operand is NaN, the result is constant. */ 11337 if (TREE_CODE (arg0) == REAL_CST 11338 && REAL_VALUE_ISNAN (TREE_REAL_CST (arg0)) 11339 && (code != LTGT_EXPR || ! flag_trapping_math)) 11340 { 11341 t1 = (code == ORDERED_EXPR || code == LTGT_EXPR) 11342 ? integer_zero_node 11343 : integer_one_node; 11344 return omit_one_operand (type, t1, arg1); 11345 } 11346 11347 /* If the second operand is NaN, the result is constant. */ 11348 if (TREE_CODE (arg1) == REAL_CST 11349 && REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)) 11350 && (code != LTGT_EXPR || ! flag_trapping_math)) 11351 { 11352 t1 = (code == ORDERED_EXPR || code == LTGT_EXPR) 11353 ? integer_zero_node 11354 : integer_one_node; 11355 return omit_one_operand (type, t1, arg0); 11356 } 11357 11358 /* Simplify unordered comparison of something with itself. */ 11359 if ((code == UNLE_EXPR || code == UNGE_EXPR || code == UNEQ_EXPR) 11360 && operand_equal_p (arg0, arg1, 0)) 11361 return constant_boolean_node (1, type); 11362 11363 if (code == LTGT_EXPR 11364 && !flag_trapping_math 11365 && operand_equal_p (arg0, arg1, 0)) 11366 return constant_boolean_node (0, type); 11367 11368 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */ 11369 { 11370 tree targ0 = strip_float_extensions (arg0); 11371 tree targ1 = strip_float_extensions (arg1); 11372 tree newtype = TREE_TYPE (targ0); 11373 11374 if (TYPE_PRECISION (TREE_TYPE (targ1)) > TYPE_PRECISION (newtype)) 11375 newtype = TREE_TYPE (targ1); 11376 11377 if (TYPE_PRECISION (newtype) < TYPE_PRECISION (TREE_TYPE (arg0))) 11378 return fold_build2 (code, type, fold_convert (newtype, targ0), 11379 fold_convert (newtype, targ1)); 11380 } 11381 11382 return NULL_TREE; 11383 11384 case COMPOUND_EXPR: 11385 /* When pedantic, a compound expression can be neither an lvalue 11386 nor an integer constant expression. */ 11387 if (TREE_SIDE_EFFECTS (arg0) || TREE_CONSTANT (arg1)) 11388 return NULL_TREE; 11389 /* Don't let (0, 0) be null pointer constant. */ 11390 tem = integer_zerop (arg1) ? build1 (NOP_EXPR, type, arg1) 11391 : fold_convert (type, arg1); 11392 return pedantic_non_lvalue (tem); 11393 11394 case COMPLEX_EXPR: 11395 if ((TREE_CODE (arg0) == REAL_CST 11396 && TREE_CODE (arg1) == REAL_CST) 11397 || (TREE_CODE (arg0) == INTEGER_CST 11398 && TREE_CODE (arg1) == INTEGER_CST)) 11399 return build_complex (type, arg0, arg1); 11400 return NULL_TREE; 11401 11402 case ASSERT_EXPR: 11403 /* An ASSERT_EXPR should never be passed to fold_binary. */ 11404 gcc_unreachable (); 11405 11406 default: 11407 return NULL_TREE; 11408 } /* switch (code) */ 11409} 11410 11411/* Callback for walk_tree, looking for LABEL_EXPR. 11412 Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE. 11413 Do not check the sub-tree of GOTO_EXPR. */ 11414 11415static tree 11416contains_label_1 (tree *tp, 11417 int *walk_subtrees, 11418 void *data ATTRIBUTE_UNUSED) 11419{ 11420 switch (TREE_CODE (*tp)) 11421 { 11422 case LABEL_EXPR: 11423 return *tp; 11424 case GOTO_EXPR: 11425 *walk_subtrees = 0; 11426 /* no break */ 11427 default: 11428 return NULL_TREE; 11429 } 11430} 11431 11432/* Checks whether the sub-tree ST contains a label LABEL_EXPR which is 11433 accessible from outside the sub-tree. Returns NULL_TREE if no 11434 addressable label is found. */ 11435 11436static bool 11437contains_label_p (tree st) 11438{ 11439 return (walk_tree (&st, contains_label_1 , NULL, NULL) != NULL_TREE); 11440} 11441 11442/* Fold a ternary expression of code CODE and type TYPE with operands 11443 OP0, OP1, and OP2. Return the folded expression if folding is 11444 successful. Otherwise, return NULL_TREE. */ 11445 11446tree 11447fold_ternary (enum tree_code code, tree type, tree op0, tree op1, tree op2) 11448{ 11449 tree tem; 11450 tree arg0 = NULL_TREE, arg1 = NULL_TREE; 11451 enum tree_code_class kind = TREE_CODE_CLASS (code); 11452 11453 gcc_assert (IS_EXPR_CODE_CLASS (kind) 11454 && TREE_CODE_LENGTH (code) == 3); 11455 11456 /* Strip any conversions that don't change the mode. This is safe 11457 for every expression, except for a comparison expression because 11458 its signedness is derived from its operands. So, in the latter 11459 case, only strip conversions that don't change the signedness. 11460 11461 Note that this is done as an internal manipulation within the 11462 constant folder, in order to find the simplest representation of 11463 the arguments so that their form can be studied. In any cases, 11464 the appropriate type conversions should be put back in the tree 11465 that will get out of the constant folder. */ 11466 if (op0) 11467 { 11468 arg0 = op0; 11469 STRIP_NOPS (arg0); 11470 } 11471 11472 if (op1) 11473 { 11474 arg1 = op1; 11475 STRIP_NOPS (arg1); 11476 } 11477 11478 switch (code) 11479 { 11480 case COMPONENT_REF: 11481 if (TREE_CODE (arg0) == CONSTRUCTOR 11482 && ! type_contains_placeholder_p (TREE_TYPE (arg0))) 11483 { 11484 unsigned HOST_WIDE_INT idx; 11485 tree field, value; 11486 FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (arg0), idx, field, value) 11487 if (field == arg1) 11488 return value; 11489 } 11490 return NULL_TREE; 11491 11492 case COND_EXPR: 11493 /* Pedantic ANSI C says that a conditional expression is never an lvalue, 11494 so all simple results must be passed through pedantic_non_lvalue. */ 11495 if (TREE_CODE (arg0) == INTEGER_CST) 11496 { 11497 tree unused_op = integer_zerop (arg0) ? op1 : op2; 11498 tem = integer_zerop (arg0) ? op2 : op1; 11499 /* Only optimize constant conditions when the selected branch 11500 has the same type as the COND_EXPR. This avoids optimizing 11501 away "c ? x : throw", where the throw has a void type. 11502 Avoid throwing away that operand which contains label. */ 11503 if ((!TREE_SIDE_EFFECTS (unused_op) 11504 || !contains_label_p (unused_op)) 11505 && (! VOID_TYPE_P (TREE_TYPE (tem)) 11506 || VOID_TYPE_P (type))) 11507 return pedantic_non_lvalue (tem); 11508 return NULL_TREE; 11509 } 11510 if (operand_equal_p (arg1, op2, 0)) 11511 return pedantic_omit_one_operand (type, arg1, arg0); 11512 11513 /* If we have A op B ? A : C, we may be able to convert this to a 11514 simpler expression, depending on the operation and the values 11515 of B and C. Signed zeros prevent all of these transformations, 11516 for reasons given above each one. 11517 11518 Also try swapping the arguments and inverting the conditional. */ 11519 if (COMPARISON_CLASS_P (arg0) 11520 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0), 11521 arg1, TREE_OPERAND (arg0, 1)) 11522 && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1)))) 11523 { 11524 tem = fold_cond_expr_with_comparison (type, arg0, op1, op2); 11525 if (tem) 11526 return tem; 11527 } 11528 11529 if (COMPARISON_CLASS_P (arg0) 11530 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0), 11531 op2, 11532 TREE_OPERAND (arg0, 1)) 11533 && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (op2)))) 11534 { 11535 tem = fold_truth_not_expr (arg0); 11536 if (tem && COMPARISON_CLASS_P (tem)) 11537 { 11538 tem = fold_cond_expr_with_comparison (type, tem, op2, op1); 11539 if (tem) 11540 return tem; 11541 } 11542 } 11543 11544 /* If the second operand is simpler than the third, swap them 11545 since that produces better jump optimization results. */ 11546 if (truth_value_p (TREE_CODE (arg0)) 11547 && tree_swap_operands_p (op1, op2, false)) 11548 { 11549 /* See if this can be inverted. If it can't, possibly because 11550 it was a floating-point inequality comparison, don't do 11551 anything. */ 11552 tem = fold_truth_not_expr (arg0); 11553 if (tem) 11554 return fold_build3 (code, type, tem, op2, op1); 11555 } 11556 11557 /* Convert A ? 1 : 0 to simply A. */ 11558 if (integer_onep (op1) 11559 && integer_zerop (op2) 11560 /* If we try to convert OP0 to our type, the 11561 call to fold will try to move the conversion inside 11562 a COND, which will recurse. In that case, the COND_EXPR 11563 is probably the best choice, so leave it alone. */ 11564 && type == TREE_TYPE (arg0)) 11565 return pedantic_non_lvalue (arg0); 11566 11567 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR 11568 over COND_EXPR in cases such as floating point comparisons. */ 11569 if (integer_zerop (op1) 11570 && integer_onep (op2) 11571 && truth_value_p (TREE_CODE (arg0))) 11572 return pedantic_non_lvalue (fold_convert (type, 11573 invert_truthvalue (arg0))); 11574 11575 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */ 11576 if (TREE_CODE (arg0) == LT_EXPR 11577 && integer_zerop (TREE_OPERAND (arg0, 1)) 11578 && integer_zerop (op2) 11579 && (tem = sign_bit_p (TREE_OPERAND (arg0, 0), arg1))) 11580 { 11581 /* sign_bit_p only checks ARG1 bits within A's precision. 11582 If <sign bit of A> has wider type than A, bits outside 11583 of A's precision in <sign bit of A> need to be checked. 11584 If they are all 0, this optimization needs to be done 11585 in unsigned A's type, if they are all 1 in signed A's type, 11586 otherwise this can't be done. */ 11587 if (TYPE_PRECISION (TREE_TYPE (tem)) 11588 < TYPE_PRECISION (TREE_TYPE (arg1)) 11589 && TYPE_PRECISION (TREE_TYPE (tem)) 11590 < TYPE_PRECISION (type)) 11591 { 11592 unsigned HOST_WIDE_INT mask_lo; 11593 HOST_WIDE_INT mask_hi; 11594 int inner_width, outer_width; 11595 tree tem_type; 11596 11597 inner_width = TYPE_PRECISION (TREE_TYPE (tem)); 11598 outer_width = TYPE_PRECISION (TREE_TYPE (arg1)); 11599 if (outer_width > TYPE_PRECISION (type)) 11600 outer_width = TYPE_PRECISION (type); 11601 11602 if (outer_width > HOST_BITS_PER_WIDE_INT) 11603 { 11604 mask_hi = ((unsigned HOST_WIDE_INT) -1 11605 >> (2 * HOST_BITS_PER_WIDE_INT - outer_width)); 11606 mask_lo = -1; 11607 } 11608 else 11609 { 11610 mask_hi = 0; 11611 mask_lo = ((unsigned HOST_WIDE_INT) -1 11612 >> (HOST_BITS_PER_WIDE_INT - outer_width)); 11613 } 11614 if (inner_width > HOST_BITS_PER_WIDE_INT) 11615 { 11616 mask_hi &= ~((unsigned HOST_WIDE_INT) -1 11617 >> (HOST_BITS_PER_WIDE_INT - inner_width)); 11618 mask_lo = 0; 11619 } 11620 else 11621 mask_lo &= ~((unsigned HOST_WIDE_INT) -1 11622 >> (HOST_BITS_PER_WIDE_INT - inner_width)); 11623 11624 if ((TREE_INT_CST_HIGH (arg1) & mask_hi) == mask_hi 11625 && (TREE_INT_CST_LOW (arg1) & mask_lo) == mask_lo) 11626 { 11627 tem_type = lang_hooks.types.signed_type (TREE_TYPE (tem)); 11628 tem = fold_convert (tem_type, tem); 11629 } 11630 else if ((TREE_INT_CST_HIGH (arg1) & mask_hi) == 0 11631 && (TREE_INT_CST_LOW (arg1) & mask_lo) == 0) 11632 { 11633 tem_type = lang_hooks.types.unsigned_type (TREE_TYPE (tem)); 11634 tem = fold_convert (tem_type, tem); 11635 } 11636 else 11637 tem = NULL; 11638 } 11639 11640 if (tem) 11641 return fold_convert (type, 11642 fold_build2 (BIT_AND_EXPR, 11643 TREE_TYPE (tem), tem, 11644 fold_convert (TREE_TYPE (tem), 11645 arg1))); 11646 } 11647 11648 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was 11649 already handled above. */ 11650 if (TREE_CODE (arg0) == BIT_AND_EXPR 11651 && integer_onep (TREE_OPERAND (arg0, 1)) 11652 && integer_zerop (op2) 11653 && integer_pow2p (arg1)) 11654 { 11655 tree tem = TREE_OPERAND (arg0, 0); 11656 STRIP_NOPS (tem); 11657 if (TREE_CODE (tem) == RSHIFT_EXPR 11658 && TREE_CODE (TREE_OPERAND (tem, 1)) == INTEGER_CST 11659 && (unsigned HOST_WIDE_INT) tree_log2 (arg1) == 11660 TREE_INT_CST_LOW (TREE_OPERAND (tem, 1))) 11661 return fold_build2 (BIT_AND_EXPR, type, 11662 TREE_OPERAND (tem, 0), arg1); 11663 } 11664 11665 /* A & N ? N : 0 is simply A & N if N is a power of two. This 11666 is probably obsolete because the first operand should be a 11667 truth value (that's why we have the two cases above), but let's 11668 leave it in until we can confirm this for all front-ends. */ 11669 if (integer_zerop (op2) 11670 && TREE_CODE (arg0) == NE_EXPR 11671 && integer_zerop (TREE_OPERAND (arg0, 1)) 11672 && integer_pow2p (arg1) 11673 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR 11674 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1), 11675 arg1, OEP_ONLY_CONST)) 11676 return pedantic_non_lvalue (fold_convert (type, 11677 TREE_OPERAND (arg0, 0))); 11678 11679 /* Convert A ? B : 0 into A && B if A and B are truth values. */ 11680 if (integer_zerop (op2) 11681 && truth_value_p (TREE_CODE (arg0)) 11682 && truth_value_p (TREE_CODE (arg1))) 11683 return fold_build2 (TRUTH_ANDIF_EXPR, type, 11684 fold_convert (type, arg0), 11685 arg1); 11686 11687 /* Convert A ? B : 1 into !A || B if A and B are truth values. */ 11688 if (integer_onep (op2) 11689 && truth_value_p (TREE_CODE (arg0)) 11690 && truth_value_p (TREE_CODE (arg1))) 11691 { 11692 /* Only perform transformation if ARG0 is easily inverted. */ 11693 tem = fold_truth_not_expr (arg0); 11694 if (tem) 11695 return fold_build2 (TRUTH_ORIF_EXPR, type, 11696 fold_convert (type, tem), 11697 arg1); 11698 } 11699 11700 /* Convert A ? 0 : B into !A && B if A and B are truth values. */ 11701 if (integer_zerop (arg1) 11702 && truth_value_p (TREE_CODE (arg0)) 11703 && truth_value_p (TREE_CODE (op2))) 11704 { 11705 /* Only perform transformation if ARG0 is easily inverted. */ 11706 tem = fold_truth_not_expr (arg0); 11707 if (tem) 11708 return fold_build2 (TRUTH_ANDIF_EXPR, type, 11709 fold_convert (type, tem), 11710 op2); 11711 } 11712 11713 /* Convert A ? 1 : B into A || B if A and B are truth values. */ 11714 if (integer_onep (arg1) 11715 && truth_value_p (TREE_CODE (arg0)) 11716 && truth_value_p (TREE_CODE (op2))) 11717 return fold_build2 (TRUTH_ORIF_EXPR, type, 11718 fold_convert (type, arg0), 11719 op2); 11720 11721 return NULL_TREE; 11722 11723 case CALL_EXPR: 11724 /* Check for a built-in function. */ 11725 if (TREE_CODE (op0) == ADDR_EXPR 11726 && TREE_CODE (TREE_OPERAND (op0, 0)) == FUNCTION_DECL 11727 && DECL_BUILT_IN (TREE_OPERAND (op0, 0))) 11728 return fold_builtin (TREE_OPERAND (op0, 0), op1, false); 11729 return NULL_TREE; 11730 11731 case BIT_FIELD_REF: 11732 if (TREE_CODE (arg0) == VECTOR_CST 11733 && type == TREE_TYPE (TREE_TYPE (arg0)) 11734 && host_integerp (arg1, 1) 11735 && host_integerp (op2, 1)) 11736 { 11737 unsigned HOST_WIDE_INT width = tree_low_cst (arg1, 1); 11738 unsigned HOST_WIDE_INT idx = tree_low_cst (op2, 1); 11739 11740 if (width != 0 11741 && simple_cst_equal (arg1, TYPE_SIZE (type)) == 1 11742 && (idx % width) == 0 11743 && (idx = idx / width) 11744 < TYPE_VECTOR_SUBPARTS (TREE_TYPE (arg0))) 11745 { 11746 tree elements = TREE_VECTOR_CST_ELTS (arg0); 11747 while (idx-- > 0 && elements) 11748 elements = TREE_CHAIN (elements); 11749 if (elements) 11750 return TREE_VALUE (elements); 11751 else 11752 return fold_convert (type, integer_zero_node); 11753 } 11754 } 11755 return NULL_TREE; 11756 11757 default: 11758 return NULL_TREE; 11759 } /* switch (code) */ 11760} 11761 11762/* Perform constant folding and related simplification of EXPR. 11763 The related simplifications include x*1 => x, x*0 => 0, etc., 11764 and application of the associative law. 11765 NOP_EXPR conversions may be removed freely (as long as we 11766 are careful not to change the type of the overall expression). 11767 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR, 11768 but we can constant-fold them if they have constant operands. */ 11769 11770#ifdef ENABLE_FOLD_CHECKING 11771# define fold(x) fold_1 (x) 11772static tree fold_1 (tree); 11773static 11774#endif 11775tree 11776fold (tree expr) 11777{ 11778 const tree t = expr; 11779 enum tree_code code = TREE_CODE (t); 11780 enum tree_code_class kind = TREE_CODE_CLASS (code); 11781 tree tem; 11782 11783 /* Return right away if a constant. */ 11784 if (kind == tcc_constant) 11785 return t; 11786 11787 if (IS_EXPR_CODE_CLASS (kind)) 11788 { 11789 tree type = TREE_TYPE (t); 11790 tree op0, op1, op2; 11791 11792 switch (TREE_CODE_LENGTH (code)) 11793 { 11794 case 1: 11795 op0 = TREE_OPERAND (t, 0); 11796 tem = fold_unary (code, type, op0); 11797 return tem ? tem : expr; 11798 case 2: 11799 op0 = TREE_OPERAND (t, 0); 11800 op1 = TREE_OPERAND (t, 1); 11801 tem = fold_binary (code, type, op0, op1); 11802 return tem ? tem : expr; 11803 case 3: 11804 op0 = TREE_OPERAND (t, 0); 11805 op1 = TREE_OPERAND (t, 1); 11806 op2 = TREE_OPERAND (t, 2); 11807 tem = fold_ternary (code, type, op0, op1, op2); 11808 return tem ? tem : expr; 11809 default: 11810 break; 11811 } 11812 } 11813 11814 switch (code) 11815 { 11816 case CONST_DECL: 11817 return fold (DECL_INITIAL (t)); 11818 11819 default: 11820 return t; 11821 } /* switch (code) */ 11822} 11823 11824#ifdef ENABLE_FOLD_CHECKING 11825#undef fold 11826 11827static void fold_checksum_tree (tree, struct md5_ctx *, htab_t); 11828static void fold_check_failed (tree, tree); 11829void print_fold_checksum (tree); 11830 11831/* When --enable-checking=fold, compute a digest of expr before 11832 and after actual fold call to see if fold did not accidentally 11833 change original expr. */ 11834 11835tree 11836fold (tree expr) 11837{ 11838 tree ret; 11839 struct md5_ctx ctx; 11840 unsigned char checksum_before[16], checksum_after[16]; 11841 htab_t ht; 11842 11843 ht = htab_create (32, htab_hash_pointer, htab_eq_pointer, NULL); 11844 md5_init_ctx (&ctx); 11845 fold_checksum_tree (expr, &ctx, ht); 11846 md5_finish_ctx (&ctx, checksum_before); 11847 htab_empty (ht); 11848 11849 ret = fold_1 (expr); 11850 11851 md5_init_ctx (&ctx); 11852 fold_checksum_tree (expr, &ctx, ht); 11853 md5_finish_ctx (&ctx, checksum_after); 11854 htab_delete (ht); 11855 11856 if (memcmp (checksum_before, checksum_after, 16)) 11857 fold_check_failed (expr, ret); 11858 11859 return ret; 11860} 11861 11862void 11863print_fold_checksum (tree expr) 11864{ 11865 struct md5_ctx ctx; 11866 unsigned char checksum[16], cnt; 11867 htab_t ht; 11868 11869 ht = htab_create (32, htab_hash_pointer, htab_eq_pointer, NULL); 11870 md5_init_ctx (&ctx); 11871 fold_checksum_tree (expr, &ctx, ht); 11872 md5_finish_ctx (&ctx, checksum); 11873 htab_delete (ht); 11874 for (cnt = 0; cnt < 16; ++cnt) 11875 fprintf (stderr, "%02x", checksum[cnt]); 11876 putc ('\n', stderr); 11877} 11878 11879static void 11880fold_check_failed (tree expr ATTRIBUTE_UNUSED, tree ret ATTRIBUTE_UNUSED) 11881{ 11882 internal_error ("fold check: original tree changed by fold"); 11883} 11884 11885static void 11886fold_checksum_tree (tree expr, struct md5_ctx *ctx, htab_t ht) 11887{ 11888 void **slot; 11889 enum tree_code code; 11890 struct tree_function_decl buf; 11891 int i, len; 11892 11893recursive_label: 11894 11895 gcc_assert ((sizeof (struct tree_exp) + 5 * sizeof (tree) 11896 <= sizeof (struct tree_function_decl)) 11897 && sizeof (struct tree_type) <= sizeof (struct tree_function_decl)); 11898 if (expr == NULL) 11899 return; 11900 slot = htab_find_slot (ht, expr, INSERT); 11901 if (*slot != NULL) 11902 return; 11903 *slot = expr; 11904 code = TREE_CODE (expr); 11905 if (TREE_CODE_CLASS (code) == tcc_declaration 11906 && DECL_ASSEMBLER_NAME_SET_P (expr)) 11907 { 11908 /* Allow DECL_ASSEMBLER_NAME to be modified. */ 11909 memcpy ((char *) &buf, expr, tree_size (expr)); 11910 expr = (tree) &buf; 11911 SET_DECL_ASSEMBLER_NAME (expr, NULL); 11912 } 11913 else if (TREE_CODE_CLASS (code) == tcc_type 11914 && (TYPE_POINTER_TO (expr) || TYPE_REFERENCE_TO (expr) 11915 || TYPE_CACHED_VALUES_P (expr) 11916 || TYPE_CONTAINS_PLACEHOLDER_INTERNAL (expr))) 11917 { 11918 /* Allow these fields to be modified. */ 11919 memcpy ((char *) &buf, expr, tree_size (expr)); 11920 expr = (tree) &buf; 11921 TYPE_CONTAINS_PLACEHOLDER_INTERNAL (expr) = 0; 11922 TYPE_POINTER_TO (expr) = NULL; 11923 TYPE_REFERENCE_TO (expr) = NULL; 11924 if (TYPE_CACHED_VALUES_P (expr)) 11925 { 11926 TYPE_CACHED_VALUES_P (expr) = 0; 11927 TYPE_CACHED_VALUES (expr) = NULL; 11928 } 11929 } 11930 md5_process_bytes (expr, tree_size (expr), ctx); 11931 fold_checksum_tree (TREE_TYPE (expr), ctx, ht); 11932 if (TREE_CODE_CLASS (code) != tcc_type 11933 && TREE_CODE_CLASS (code) != tcc_declaration 11934 && code != TREE_LIST) 11935 fold_checksum_tree (TREE_CHAIN (expr), ctx, ht); 11936 switch (TREE_CODE_CLASS (code)) 11937 { 11938 case tcc_constant: 11939 switch (code) 11940 { 11941 case STRING_CST: 11942 md5_process_bytes (TREE_STRING_POINTER (expr), 11943 TREE_STRING_LENGTH (expr), ctx); 11944 break; 11945 case COMPLEX_CST: 11946 fold_checksum_tree (TREE_REALPART (expr), ctx, ht); 11947 fold_checksum_tree (TREE_IMAGPART (expr), ctx, ht); 11948 break; 11949 case VECTOR_CST: 11950 fold_checksum_tree (TREE_VECTOR_CST_ELTS (expr), ctx, ht); 11951 break; 11952 default: 11953 break; 11954 } 11955 break; 11956 case tcc_exceptional: 11957 switch (code) 11958 { 11959 case TREE_LIST: 11960 fold_checksum_tree (TREE_PURPOSE (expr), ctx, ht); 11961 fold_checksum_tree (TREE_VALUE (expr), ctx, ht); 11962 expr = TREE_CHAIN (expr); 11963 goto recursive_label; 11964 break; 11965 case TREE_VEC: 11966 for (i = 0; i < TREE_VEC_LENGTH (expr); ++i) 11967 fold_checksum_tree (TREE_VEC_ELT (expr, i), ctx, ht); 11968 break; 11969 default: 11970 break; 11971 } 11972 break; 11973 case tcc_expression: 11974 case tcc_reference: 11975 case tcc_comparison: 11976 case tcc_unary: 11977 case tcc_binary: 11978 case tcc_statement: 11979 len = TREE_CODE_LENGTH (code); 11980 for (i = 0; i < len; ++i) 11981 fold_checksum_tree (TREE_OPERAND (expr, i), ctx, ht); 11982 break; 11983 case tcc_declaration: 11984 fold_checksum_tree (DECL_NAME (expr), ctx, ht); 11985 fold_checksum_tree (DECL_CONTEXT (expr), ctx, ht); 11986 if (CODE_CONTAINS_STRUCT (TREE_CODE (expr), TS_DECL_COMMON)) 11987 { 11988 fold_checksum_tree (DECL_SIZE (expr), ctx, ht); 11989 fold_checksum_tree (DECL_SIZE_UNIT (expr), ctx, ht); 11990 fold_checksum_tree (DECL_INITIAL (expr), ctx, ht); 11991 fold_checksum_tree (DECL_ABSTRACT_ORIGIN (expr), ctx, ht); 11992 fold_checksum_tree (DECL_ATTRIBUTES (expr), ctx, ht); 11993 } 11994 if (CODE_CONTAINS_STRUCT (TREE_CODE (expr), TS_DECL_WITH_VIS)) 11995 fold_checksum_tree (DECL_SECTION_NAME (expr), ctx, ht); 11996 11997 if (CODE_CONTAINS_STRUCT (TREE_CODE (expr), TS_DECL_NON_COMMON)) 11998 { 11999 fold_checksum_tree (DECL_VINDEX (expr), ctx, ht); 12000 fold_checksum_tree (DECL_RESULT_FLD (expr), ctx, ht); 12001 fold_checksum_tree (DECL_ARGUMENT_FLD (expr), ctx, ht); 12002 } 12003 break; 12004 case tcc_type: 12005 if (TREE_CODE (expr) == ENUMERAL_TYPE) 12006 fold_checksum_tree (TYPE_VALUES (expr), ctx, ht); 12007 fold_checksum_tree (TYPE_SIZE (expr), ctx, ht); 12008 fold_checksum_tree (TYPE_SIZE_UNIT (expr), ctx, ht); 12009 fold_checksum_tree (TYPE_ATTRIBUTES (expr), ctx, ht); 12010 fold_checksum_tree (TYPE_NAME (expr), ctx, ht); 12011 if (INTEGRAL_TYPE_P (expr) 12012 || SCALAR_FLOAT_TYPE_P (expr)) 12013 { 12014 fold_checksum_tree (TYPE_MIN_VALUE (expr), ctx, ht); 12015 fold_checksum_tree (TYPE_MAX_VALUE (expr), ctx, ht); 12016 } 12017 fold_checksum_tree (TYPE_MAIN_VARIANT (expr), ctx, ht); 12018 if (TREE_CODE (expr) == RECORD_TYPE 12019 || TREE_CODE (expr) == UNION_TYPE 12020 || TREE_CODE (expr) == QUAL_UNION_TYPE) 12021 fold_checksum_tree (TYPE_BINFO (expr), ctx, ht); 12022 fold_checksum_tree (TYPE_CONTEXT (expr), ctx, ht); 12023 break; 12024 default: 12025 break; 12026 } 12027} 12028 12029#endif 12030 12031/* Fold a unary tree expression with code CODE of type TYPE with an 12032 operand OP0. Return a folded expression if successful. Otherwise, 12033 return a tree expression with code CODE of type TYPE with an 12034 operand OP0. */ 12035 12036tree 12037fold_build1_stat (enum tree_code code, tree type, tree op0 MEM_STAT_DECL) 12038{ 12039 tree tem; 12040#ifdef ENABLE_FOLD_CHECKING 12041 unsigned char checksum_before[16], checksum_after[16]; 12042 struct md5_ctx ctx; 12043 htab_t ht; 12044 12045 ht = htab_create (32, htab_hash_pointer, htab_eq_pointer, NULL); 12046 md5_init_ctx (&ctx); 12047 fold_checksum_tree (op0, &ctx, ht); 12048 md5_finish_ctx (&ctx, checksum_before); 12049 htab_empty (ht); 12050#endif 12051 12052 tem = fold_unary (code, type, op0); 12053 if (!tem) 12054 tem = build1_stat (code, type, op0 PASS_MEM_STAT); 12055 12056#ifdef ENABLE_FOLD_CHECKING 12057 md5_init_ctx (&ctx); 12058 fold_checksum_tree (op0, &ctx, ht); 12059 md5_finish_ctx (&ctx, checksum_after); 12060 htab_delete (ht); 12061 12062 if (memcmp (checksum_before, checksum_after, 16)) 12063 fold_check_failed (op0, tem); 12064#endif 12065 return tem; 12066} 12067 12068/* Fold a binary tree expression with code CODE of type TYPE with 12069 operands OP0 and OP1. Return a folded expression if successful. 12070 Otherwise, return a tree expression with code CODE of type TYPE 12071 with operands OP0 and OP1. */ 12072 12073tree 12074fold_build2_stat (enum tree_code code, tree type, tree op0, tree op1 12075 MEM_STAT_DECL) 12076{ 12077 tree tem; 12078#ifdef ENABLE_FOLD_CHECKING 12079 unsigned char checksum_before_op0[16], 12080 checksum_before_op1[16], 12081 checksum_after_op0[16], 12082 checksum_after_op1[16]; 12083 struct md5_ctx ctx; 12084 htab_t ht; 12085 12086 ht = htab_create (32, htab_hash_pointer, htab_eq_pointer, NULL); 12087 md5_init_ctx (&ctx); 12088 fold_checksum_tree (op0, &ctx, ht); 12089 md5_finish_ctx (&ctx, checksum_before_op0); 12090 htab_empty (ht); 12091 12092 md5_init_ctx (&ctx); 12093 fold_checksum_tree (op1, &ctx, ht); 12094 md5_finish_ctx (&ctx, checksum_before_op1); 12095 htab_empty (ht); 12096#endif 12097 12098 tem = fold_binary (code, type, op0, op1); 12099 if (!tem) 12100 tem = build2_stat (code, type, op0, op1 PASS_MEM_STAT); 12101 12102#ifdef ENABLE_FOLD_CHECKING 12103 md5_init_ctx (&ctx); 12104 fold_checksum_tree (op0, &ctx, ht); 12105 md5_finish_ctx (&ctx, checksum_after_op0); 12106 htab_empty (ht); 12107 12108 if (memcmp (checksum_before_op0, checksum_after_op0, 16)) 12109 fold_check_failed (op0, tem); 12110 12111 md5_init_ctx (&ctx); 12112 fold_checksum_tree (op1, &ctx, ht); 12113 md5_finish_ctx (&ctx, checksum_after_op1); 12114 htab_delete (ht); 12115 12116 if (memcmp (checksum_before_op1, checksum_after_op1, 16)) 12117 fold_check_failed (op1, tem); 12118#endif 12119 return tem; 12120} 12121 12122/* Fold a ternary tree expression with code CODE of type TYPE with 12123 operands OP0, OP1, and OP2. Return a folded expression if 12124 successful. Otherwise, return a tree expression with code CODE of 12125 type TYPE with operands OP0, OP1, and OP2. */ 12126 12127tree 12128fold_build3_stat (enum tree_code code, tree type, tree op0, tree op1, tree op2 12129 MEM_STAT_DECL) 12130{ 12131 tree tem; 12132#ifdef ENABLE_FOLD_CHECKING 12133 unsigned char checksum_before_op0[16], 12134 checksum_before_op1[16], 12135 checksum_before_op2[16], 12136 checksum_after_op0[16], 12137 checksum_after_op1[16], 12138 checksum_after_op2[16]; 12139 struct md5_ctx ctx; 12140 htab_t ht; 12141 12142 ht = htab_create (32, htab_hash_pointer, htab_eq_pointer, NULL); 12143 md5_init_ctx (&ctx); 12144 fold_checksum_tree (op0, &ctx, ht); 12145 md5_finish_ctx (&ctx, checksum_before_op0); 12146 htab_empty (ht); 12147 12148 md5_init_ctx (&ctx); 12149 fold_checksum_tree (op1, &ctx, ht); 12150 md5_finish_ctx (&ctx, checksum_before_op1); 12151 htab_empty (ht); 12152 12153 md5_init_ctx (&ctx); 12154 fold_checksum_tree (op2, &ctx, ht); 12155 md5_finish_ctx (&ctx, checksum_before_op2); 12156 htab_empty (ht); 12157#endif 12158 12159 tem = fold_ternary (code, type, op0, op1, op2); 12160 if (!tem) 12161 tem = build3_stat (code, type, op0, op1, op2 PASS_MEM_STAT); 12162 12163#ifdef ENABLE_FOLD_CHECKING 12164 md5_init_ctx (&ctx); 12165 fold_checksum_tree (op0, &ctx, ht); 12166 md5_finish_ctx (&ctx, checksum_after_op0); 12167 htab_empty (ht); 12168 12169 if (memcmp (checksum_before_op0, checksum_after_op0, 16)) 12170 fold_check_failed (op0, tem); 12171 12172 md5_init_ctx (&ctx); 12173 fold_checksum_tree (op1, &ctx, ht); 12174 md5_finish_ctx (&ctx, checksum_after_op1); 12175 htab_empty (ht); 12176 12177 if (memcmp (checksum_before_op1, checksum_after_op1, 16)) 12178 fold_check_failed (op1, tem); 12179 12180 md5_init_ctx (&ctx); 12181 fold_checksum_tree (op2, &ctx, ht); 12182 md5_finish_ctx (&ctx, checksum_after_op2); 12183 htab_delete (ht); 12184 12185 if (memcmp (checksum_before_op2, checksum_after_op2, 16)) 12186 fold_check_failed (op2, tem); 12187#endif 12188 return tem; 12189} 12190 12191/* Perform constant folding and related simplification of initializer 12192 expression EXPR. These behave identically to "fold_buildN" but ignore 12193 potential run-time traps and exceptions that fold must preserve. */ 12194 12195#define START_FOLD_INIT \ 12196 int saved_signaling_nans = flag_signaling_nans;\ 12197 int saved_trapping_math = flag_trapping_math;\ 12198 int saved_rounding_math = flag_rounding_math;\ 12199 int saved_trapv = flag_trapv;\ 12200 int saved_folding_initializer = folding_initializer;\ 12201 flag_signaling_nans = 0;\ 12202 flag_trapping_math = 0;\ 12203 flag_rounding_math = 0;\ 12204 flag_trapv = 0;\ 12205 folding_initializer = 1; 12206 12207#define END_FOLD_INIT \ 12208 flag_signaling_nans = saved_signaling_nans;\ 12209 flag_trapping_math = saved_trapping_math;\ 12210 flag_rounding_math = saved_rounding_math;\ 12211 flag_trapv = saved_trapv;\ 12212 folding_initializer = saved_folding_initializer; 12213 12214tree 12215fold_build1_initializer (enum tree_code code, tree type, tree op) 12216{ 12217 tree result; 12218 START_FOLD_INIT; 12219 12220 result = fold_build1 (code, type, op); 12221 12222 END_FOLD_INIT; 12223 return result; 12224} 12225 12226tree 12227fold_build2_initializer (enum tree_code code, tree type, tree op0, tree op1) 12228{ 12229 tree result; 12230 START_FOLD_INIT; 12231 12232 result = fold_build2 (code, type, op0, op1); 12233 12234 END_FOLD_INIT; 12235 return result; 12236} 12237 12238tree 12239fold_build3_initializer (enum tree_code code, tree type, tree op0, tree op1, 12240 tree op2) 12241{ 12242 tree result; 12243 START_FOLD_INIT; 12244 12245 result = fold_build3 (code, type, op0, op1, op2); 12246 12247 END_FOLD_INIT; 12248 return result; 12249} 12250 12251#undef START_FOLD_INIT 12252#undef END_FOLD_INIT 12253 12254/* Determine if first argument is a multiple of second argument. Return 0 if 12255 it is not, or we cannot easily determined it to be. 12256 12257 An example of the sort of thing we care about (at this point; this routine 12258 could surely be made more general, and expanded to do what the *_DIV_EXPR's 12259 fold cases do now) is discovering that 12260 12261 SAVE_EXPR (I) * SAVE_EXPR (J * 8) 12262 12263 is a multiple of 12264 12265 SAVE_EXPR (J * 8) 12266 12267 when we know that the two SAVE_EXPR (J * 8) nodes are the same node. 12268 12269 This code also handles discovering that 12270 12271 SAVE_EXPR (I) * SAVE_EXPR (J * 8) 12272 12273 is a multiple of 8 so we don't have to worry about dealing with a 12274 possible remainder. 12275 12276 Note that we *look* inside a SAVE_EXPR only to determine how it was 12277 calculated; it is not safe for fold to do much of anything else with the 12278 internals of a SAVE_EXPR, since it cannot know when it will be evaluated 12279 at run time. For example, the latter example above *cannot* be implemented 12280 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at 12281 evaluation time of the original SAVE_EXPR is not necessarily the same at 12282 the time the new expression is evaluated. The only optimization of this 12283 sort that would be valid is changing 12284 12285 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8) 12286 12287 divided by 8 to 12288 12289 SAVE_EXPR (I) * SAVE_EXPR (J) 12290 12291 (where the same SAVE_EXPR (J) is used in the original and the 12292 transformed version). */ 12293 12294static int 12295multiple_of_p (tree type, tree top, tree bottom) 12296{ 12297 if (operand_equal_p (top, bottom, 0)) 12298 return 1; 12299 12300 if (TREE_CODE (type) != INTEGER_TYPE) 12301 return 0; 12302 12303 switch (TREE_CODE (top)) 12304 { 12305 case BIT_AND_EXPR: 12306 /* Bitwise and provides a power of two multiple. If the mask is 12307 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */ 12308 if (!integer_pow2p (bottom)) 12309 return 0; 12310 /* FALLTHRU */ 12311 12312 case MULT_EXPR: 12313 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom) 12314 || multiple_of_p (type, TREE_OPERAND (top, 1), bottom)); 12315 12316 case PLUS_EXPR: 12317 case MINUS_EXPR: 12318 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom) 12319 && multiple_of_p (type, TREE_OPERAND (top, 1), bottom)); 12320 12321 case LSHIFT_EXPR: 12322 if (TREE_CODE (TREE_OPERAND (top, 1)) == INTEGER_CST) 12323 { 12324 tree op1, t1; 12325 12326 op1 = TREE_OPERAND (top, 1); 12327 /* const_binop may not detect overflow correctly, 12328 so check for it explicitly here. */ 12329 if (TYPE_PRECISION (TREE_TYPE (size_one_node)) 12330 > TREE_INT_CST_LOW (op1) 12331 && TREE_INT_CST_HIGH (op1) == 0 12332 && 0 != (t1 = fold_convert (type, 12333 const_binop (LSHIFT_EXPR, 12334 size_one_node, 12335 op1, 0))) 12336 && ! TREE_OVERFLOW (t1)) 12337 return multiple_of_p (type, t1, bottom); 12338 } 12339 return 0; 12340 12341 case NOP_EXPR: 12342 /* Can't handle conversions from non-integral or wider integral type. */ 12343 if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE) 12344 || (TYPE_PRECISION (type) 12345 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0))))) 12346 return 0; 12347 12348 /* .. fall through ... */ 12349 12350 case SAVE_EXPR: 12351 return multiple_of_p (type, TREE_OPERAND (top, 0), bottom); 12352 12353 case INTEGER_CST: 12354 if (TREE_CODE (bottom) != INTEGER_CST 12355 || (TYPE_UNSIGNED (type) 12356 && (tree_int_cst_sgn (top) < 0 12357 || tree_int_cst_sgn (bottom) < 0))) 12358 return 0; 12359 return integer_zerop (const_binop (TRUNC_MOD_EXPR, 12360 top, bottom, 0)); 12361 12362 default: 12363 return 0; 12364 } 12365} 12366 12367/* Return true if `t' is known to be non-negative. If the return 12368 value is based on the assumption that signed overflow is undefined, 12369 set *STRICT_OVERFLOW_P to true; otherwise, don't change 12370 *STRICT_OVERFLOW_P. */ 12371 12372int 12373tree_expr_nonnegative_warnv_p (tree t, bool *strict_overflow_p) 12374{ 12375 if (t == error_mark_node) 12376 return 0; 12377 12378 if (TYPE_UNSIGNED (TREE_TYPE (t))) 12379 return 1; 12380 12381 switch (TREE_CODE (t)) 12382 { 12383 case SSA_NAME: 12384 /* Query VRP to see if it has recorded any information about 12385 the range of this object. */ 12386 return ssa_name_nonnegative_p (t); 12387 12388 case ABS_EXPR: 12389 /* We can't return 1 if flag_wrapv is set because 12390 ABS_EXPR<INT_MIN> = INT_MIN. */ 12391 if (!INTEGRAL_TYPE_P (TREE_TYPE (t))) 12392 return 1; 12393 if (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (t))) 12394 { 12395 *strict_overflow_p = true; 12396 return 1; 12397 } 12398 break; 12399 12400 case INTEGER_CST: 12401 return tree_int_cst_sgn (t) >= 0; 12402 12403 case REAL_CST: 12404 return ! REAL_VALUE_NEGATIVE (TREE_REAL_CST (t)); 12405 12406 case PLUS_EXPR: 12407 if (FLOAT_TYPE_P (TREE_TYPE (t))) 12408 return (tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 0), 12409 strict_overflow_p) 12410 && tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 1), 12411 strict_overflow_p)); 12412 12413 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are 12414 both unsigned and at least 2 bits shorter than the result. */ 12415 if (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE 12416 && TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR 12417 && TREE_CODE (TREE_OPERAND (t, 1)) == NOP_EXPR) 12418 { 12419 tree inner1 = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)); 12420 tree inner2 = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)); 12421 if (TREE_CODE (inner1) == INTEGER_TYPE && TYPE_UNSIGNED (inner1) 12422 && TREE_CODE (inner2) == INTEGER_TYPE && TYPE_UNSIGNED (inner2)) 12423 { 12424 unsigned int prec = MAX (TYPE_PRECISION (inner1), 12425 TYPE_PRECISION (inner2)) + 1; 12426 return prec < TYPE_PRECISION (TREE_TYPE (t)); 12427 } 12428 } 12429 break; 12430 12431 case MULT_EXPR: 12432 if (FLOAT_TYPE_P (TREE_TYPE (t))) 12433 { 12434 /* x * x for floating point x is always non-negative. */ 12435 if (operand_equal_p (TREE_OPERAND (t, 0), TREE_OPERAND (t, 1), 0)) 12436 return 1; 12437 return (tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 0), 12438 strict_overflow_p) 12439 && tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 1), 12440 strict_overflow_p)); 12441 } 12442 12443 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are 12444 both unsigned and their total bits is shorter than the result. */ 12445 if (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE 12446 && TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR 12447 && TREE_CODE (TREE_OPERAND (t, 1)) == NOP_EXPR) 12448 { 12449 tree inner1 = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)); 12450 tree inner2 = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)); 12451 if (TREE_CODE (inner1) == INTEGER_TYPE && TYPE_UNSIGNED (inner1) 12452 && TREE_CODE (inner2) == INTEGER_TYPE && TYPE_UNSIGNED (inner2)) 12453 return TYPE_PRECISION (inner1) + TYPE_PRECISION (inner2) 12454 < TYPE_PRECISION (TREE_TYPE (t)); 12455 } 12456 return 0; 12457 12458 case BIT_AND_EXPR: 12459 case MAX_EXPR: 12460 return (tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 0), 12461 strict_overflow_p) 12462 || tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 1), 12463 strict_overflow_p)); 12464 12465 case BIT_IOR_EXPR: 12466 case BIT_XOR_EXPR: 12467 case MIN_EXPR: 12468 case RDIV_EXPR: 12469 case TRUNC_DIV_EXPR: 12470 case CEIL_DIV_EXPR: 12471 case FLOOR_DIV_EXPR: 12472 case ROUND_DIV_EXPR: 12473 return (tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 0), 12474 strict_overflow_p) 12475 && tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 1), 12476 strict_overflow_p)); 12477 12478 case TRUNC_MOD_EXPR: 12479 case CEIL_MOD_EXPR: 12480 case FLOOR_MOD_EXPR: 12481 case ROUND_MOD_EXPR: 12482 case SAVE_EXPR: 12483 case NON_LVALUE_EXPR: 12484 case FLOAT_EXPR: 12485 case FIX_TRUNC_EXPR: 12486 return tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 0), 12487 strict_overflow_p); 12488 12489 case COMPOUND_EXPR: 12490 case MODIFY_EXPR: 12491 return tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 1), 12492 strict_overflow_p); 12493 12494 case BIND_EXPR: 12495 return tree_expr_nonnegative_warnv_p (expr_last (TREE_OPERAND (t, 1)), 12496 strict_overflow_p); 12497 12498 case COND_EXPR: 12499 return (tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 1), 12500 strict_overflow_p) 12501 && tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 2), 12502 strict_overflow_p)); 12503 12504 case NOP_EXPR: 12505 { 12506 tree inner_type = TREE_TYPE (TREE_OPERAND (t, 0)); 12507 tree outer_type = TREE_TYPE (t); 12508 12509 if (TREE_CODE (outer_type) == REAL_TYPE) 12510 { 12511 if (TREE_CODE (inner_type) == REAL_TYPE) 12512 return tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 0), 12513 strict_overflow_p); 12514 if (TREE_CODE (inner_type) == INTEGER_TYPE) 12515 { 12516 if (TYPE_UNSIGNED (inner_type)) 12517 return 1; 12518 return tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 0), 12519 strict_overflow_p); 12520 } 12521 } 12522 else if (TREE_CODE (outer_type) == INTEGER_TYPE) 12523 { 12524 if (TREE_CODE (inner_type) == REAL_TYPE) 12525 return tree_expr_nonnegative_warnv_p (TREE_OPERAND (t,0), 12526 strict_overflow_p); 12527 if (TREE_CODE (inner_type) == INTEGER_TYPE) 12528 return TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type) 12529 && TYPE_UNSIGNED (inner_type); 12530 } 12531 } 12532 break; 12533 12534 case TARGET_EXPR: 12535 { 12536 tree temp = TARGET_EXPR_SLOT (t); 12537 t = TARGET_EXPR_INITIAL (t); 12538 12539 /* If the initializer is non-void, then it's a normal expression 12540 that will be assigned to the slot. */ 12541 if (!VOID_TYPE_P (t)) 12542 return tree_expr_nonnegative_warnv_p (t, strict_overflow_p); 12543 12544 /* Otherwise, the initializer sets the slot in some way. One common 12545 way is an assignment statement at the end of the initializer. */ 12546 while (1) 12547 { 12548 if (TREE_CODE (t) == BIND_EXPR) 12549 t = expr_last (BIND_EXPR_BODY (t)); 12550 else if (TREE_CODE (t) == TRY_FINALLY_EXPR 12551 || TREE_CODE (t) == TRY_CATCH_EXPR) 12552 t = expr_last (TREE_OPERAND (t, 0)); 12553 else if (TREE_CODE (t) == STATEMENT_LIST) 12554 t = expr_last (t); 12555 else 12556 break; 12557 } 12558 if (TREE_CODE (t) == MODIFY_EXPR 12559 && TREE_OPERAND (t, 0) == temp) 12560 return tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 1), 12561 strict_overflow_p); 12562 12563 return 0; 12564 } 12565 12566 case CALL_EXPR: 12567 { 12568 tree fndecl = get_callee_fndecl (t); 12569 tree arglist = TREE_OPERAND (t, 1); 12570 if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) 12571 switch (DECL_FUNCTION_CODE (fndecl)) 12572 { 12573 CASE_FLT_FN (BUILT_IN_ACOS): 12574 CASE_FLT_FN (BUILT_IN_ACOSH): 12575 CASE_FLT_FN (BUILT_IN_CABS): 12576 CASE_FLT_FN (BUILT_IN_COSH): 12577 CASE_FLT_FN (BUILT_IN_ERFC): 12578 CASE_FLT_FN (BUILT_IN_EXP): 12579 CASE_FLT_FN (BUILT_IN_EXP10): 12580 CASE_FLT_FN (BUILT_IN_EXP2): 12581 CASE_FLT_FN (BUILT_IN_FABS): 12582 CASE_FLT_FN (BUILT_IN_FDIM): 12583 CASE_FLT_FN (BUILT_IN_HYPOT): 12584 CASE_FLT_FN (BUILT_IN_POW10): 12585 CASE_INT_FN (BUILT_IN_FFS): 12586 CASE_INT_FN (BUILT_IN_PARITY): 12587 CASE_INT_FN (BUILT_IN_POPCOUNT): 12588 /* Always true. */ 12589 return 1; 12590 12591 CASE_FLT_FN (BUILT_IN_SQRT): 12592 /* sqrt(-0.0) is -0.0. */ 12593 if (!HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (t)))) 12594 return 1; 12595 return tree_expr_nonnegative_warnv_p (TREE_VALUE (arglist), 12596 strict_overflow_p); 12597 12598 CASE_FLT_FN (BUILT_IN_ASINH): 12599 CASE_FLT_FN (BUILT_IN_ATAN): 12600 CASE_FLT_FN (BUILT_IN_ATANH): 12601 CASE_FLT_FN (BUILT_IN_CBRT): 12602 CASE_FLT_FN (BUILT_IN_CEIL): 12603 CASE_FLT_FN (BUILT_IN_ERF): 12604 CASE_FLT_FN (BUILT_IN_EXPM1): 12605 CASE_FLT_FN (BUILT_IN_FLOOR): 12606 CASE_FLT_FN (BUILT_IN_FMOD): 12607 CASE_FLT_FN (BUILT_IN_FREXP): 12608 CASE_FLT_FN (BUILT_IN_LCEIL): 12609 CASE_FLT_FN (BUILT_IN_LDEXP): 12610 CASE_FLT_FN (BUILT_IN_LFLOOR): 12611 CASE_FLT_FN (BUILT_IN_LLCEIL): 12612 CASE_FLT_FN (BUILT_IN_LLFLOOR): 12613 CASE_FLT_FN (BUILT_IN_LLRINT): 12614 CASE_FLT_FN (BUILT_IN_LLROUND): 12615 CASE_FLT_FN (BUILT_IN_LRINT): 12616 CASE_FLT_FN (BUILT_IN_LROUND): 12617 CASE_FLT_FN (BUILT_IN_MODF): 12618 CASE_FLT_FN (BUILT_IN_NEARBYINT): 12619 CASE_FLT_FN (BUILT_IN_POW): 12620 CASE_FLT_FN (BUILT_IN_RINT): 12621 CASE_FLT_FN (BUILT_IN_ROUND): 12622 CASE_FLT_FN (BUILT_IN_SIGNBIT): 12623 CASE_FLT_FN (BUILT_IN_SINH): 12624 CASE_FLT_FN (BUILT_IN_TANH): 12625 CASE_FLT_FN (BUILT_IN_TRUNC): 12626 /* True if the 1st argument is nonnegative. */ 12627 return tree_expr_nonnegative_warnv_p (TREE_VALUE (arglist), 12628 strict_overflow_p); 12629 12630 CASE_FLT_FN (BUILT_IN_FMAX): 12631 /* True if the 1st OR 2nd arguments are nonnegative. */ 12632 return (tree_expr_nonnegative_warnv_p (TREE_VALUE (arglist), 12633 strict_overflow_p) 12634 || (tree_expr_nonnegative_warnv_p 12635 (TREE_VALUE (TREE_CHAIN (arglist)), 12636 strict_overflow_p))); 12637 12638 CASE_FLT_FN (BUILT_IN_FMIN): 12639 /* True if the 1st AND 2nd arguments are nonnegative. */ 12640 return (tree_expr_nonnegative_warnv_p (TREE_VALUE (arglist), 12641 strict_overflow_p) 12642 && (tree_expr_nonnegative_warnv_p 12643 (TREE_VALUE (TREE_CHAIN (arglist)), 12644 strict_overflow_p))); 12645 12646 CASE_FLT_FN (BUILT_IN_COPYSIGN): 12647 /* True if the 2nd argument is nonnegative. */ 12648 return (tree_expr_nonnegative_warnv_p 12649 (TREE_VALUE (TREE_CHAIN (arglist)), 12650 strict_overflow_p)); 12651 12652 default: 12653 break; 12654 } 12655 } 12656 12657 /* ... fall through ... */ 12658 12659 default: 12660 { 12661 tree type = TREE_TYPE (t); 12662 if ((TYPE_PRECISION (type) != 1 || TYPE_UNSIGNED (type)) 12663 && truth_value_p (TREE_CODE (t))) 12664 /* Truth values evaluate to 0 or 1, which is nonnegative unless we 12665 have a signed:1 type (where the value is -1 and 0). */ 12666 return true; 12667 } 12668 } 12669 12670 /* We don't know sign of `t', so be conservative and return false. */ 12671 return 0; 12672} 12673 12674/* Return true if `t' is known to be non-negative. Handle warnings 12675 about undefined signed overflow. */ 12676 12677int 12678tree_expr_nonnegative_p (tree t) 12679{ 12680 int ret; 12681 bool strict_overflow_p; 12682 12683 strict_overflow_p = false; 12684 ret = tree_expr_nonnegative_warnv_p (t, &strict_overflow_p); 12685 if (strict_overflow_p) 12686 fold_overflow_warning (("assuming signed overflow does not occur when " 12687 "determining that expression is always " 12688 "non-negative"), 12689 WARN_STRICT_OVERFLOW_MISC); 12690 return ret; 12691} 12692 12693/* Return true when T is an address and is known to be nonzero. 12694 For floating point we further ensure that T is not denormal. 12695 Similar logic is present in nonzero_address in rtlanal.h. 12696 12697 If the return value is based on the assumption that signed overflow 12698 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't 12699 change *STRICT_OVERFLOW_P. */ 12700 12701bool 12702tree_expr_nonzero_warnv_p (tree t, bool *strict_overflow_p) 12703{ 12704 tree type = TREE_TYPE (t); 12705 bool sub_strict_overflow_p; 12706 12707 /* Doing something useful for floating point would need more work. */ 12708 if (!INTEGRAL_TYPE_P (type) && !POINTER_TYPE_P (type)) 12709 return false; 12710 12711 switch (TREE_CODE (t)) 12712 { 12713 case SSA_NAME: 12714 /* Query VRP to see if it has recorded any information about 12715 the range of this object. */ 12716 return ssa_name_nonzero_p (t); 12717 12718 case ABS_EXPR: 12719 return tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 0), 12720 strict_overflow_p); 12721 12722 case INTEGER_CST: 12723 /* We used to test for !integer_zerop here. This does not work correctly 12724 if TREE_CONSTANT_OVERFLOW (t). */ 12725 return (TREE_INT_CST_LOW (t) != 0 12726 || TREE_INT_CST_HIGH (t) != 0); 12727 12728 case PLUS_EXPR: 12729 if (TYPE_OVERFLOW_UNDEFINED (type)) 12730 { 12731 /* With the presence of negative values it is hard 12732 to say something. */ 12733 sub_strict_overflow_p = false; 12734 if (!tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 0), 12735 &sub_strict_overflow_p) 12736 || !tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 1), 12737 &sub_strict_overflow_p)) 12738 return false; 12739 /* One of operands must be positive and the other non-negative. */ 12740 /* We don't set *STRICT_OVERFLOW_P here: even if this value 12741 overflows, on a twos-complement machine the sum of two 12742 nonnegative numbers can never be zero. */ 12743 return (tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 0), 12744 strict_overflow_p) 12745 || tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 1), 12746 strict_overflow_p)); 12747 } 12748 break; 12749 12750 case MULT_EXPR: 12751 if (TYPE_OVERFLOW_UNDEFINED (type)) 12752 { 12753 if (tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 0), 12754 strict_overflow_p) 12755 && tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 1), 12756 strict_overflow_p)) 12757 { 12758 *strict_overflow_p = true; 12759 return true; 12760 } 12761 } 12762 break; 12763 12764 case NOP_EXPR: 12765 { 12766 tree inner_type = TREE_TYPE (TREE_OPERAND (t, 0)); 12767 tree outer_type = TREE_TYPE (t); 12768 12769 return (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type) 12770 && tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 0), 12771 strict_overflow_p)); 12772 } 12773 break; 12774 12775 case ADDR_EXPR: 12776 { 12777 tree base = get_base_address (TREE_OPERAND (t, 0)); 12778 12779 if (!base) 12780 return false; 12781 12782 /* Weak declarations may link to NULL. */ 12783 if (VAR_OR_FUNCTION_DECL_P (base)) 12784 return !DECL_WEAK (base); 12785 12786 /* Constants are never weak. */ 12787 if (CONSTANT_CLASS_P (base)) 12788 return true; 12789 12790 return false; 12791 } 12792 12793 case COND_EXPR: 12794 sub_strict_overflow_p = false; 12795 if (tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 1), 12796 &sub_strict_overflow_p) 12797 && tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 2), 12798 &sub_strict_overflow_p)) 12799 { 12800 if (sub_strict_overflow_p) 12801 *strict_overflow_p = true; 12802 return true; 12803 } 12804 break; 12805 12806 case MIN_EXPR: 12807 sub_strict_overflow_p = false; 12808 if (tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 0), 12809 &sub_strict_overflow_p) 12810 && tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 1), 12811 &sub_strict_overflow_p)) 12812 { 12813 if (sub_strict_overflow_p) 12814 *strict_overflow_p = true; 12815 } 12816 break; 12817 12818 case MAX_EXPR: 12819 sub_strict_overflow_p = false; 12820 if (tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 0), 12821 &sub_strict_overflow_p)) 12822 { 12823 if (sub_strict_overflow_p) 12824 *strict_overflow_p = true; 12825 12826 /* When both operands are nonzero, then MAX must be too. */ 12827 if (tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 1), 12828 strict_overflow_p)) 12829 return true; 12830 12831 /* MAX where operand 0 is positive is positive. */ 12832 return tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 0), 12833 strict_overflow_p); 12834 } 12835 /* MAX where operand 1 is positive is positive. */ 12836 else if (tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 1), 12837 &sub_strict_overflow_p) 12838 && tree_expr_nonnegative_warnv_p (TREE_OPERAND (t, 1), 12839 &sub_strict_overflow_p)) 12840 { 12841 if (sub_strict_overflow_p) 12842 *strict_overflow_p = true; 12843 return true; 12844 } 12845 break; 12846 12847 case COMPOUND_EXPR: 12848 case MODIFY_EXPR: 12849 case BIND_EXPR: 12850 return tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 1), 12851 strict_overflow_p); 12852 12853 case SAVE_EXPR: 12854 case NON_LVALUE_EXPR: 12855 return tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 0), 12856 strict_overflow_p); 12857 12858 case BIT_IOR_EXPR: 12859 return (tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 1), 12860 strict_overflow_p) 12861 || tree_expr_nonzero_warnv_p (TREE_OPERAND (t, 0), 12862 strict_overflow_p)); 12863 12864 case CALL_EXPR: 12865 return alloca_call_p (t); 12866 12867 default: 12868 break; 12869 } 12870 return false; 12871} 12872 12873/* Return true when T is an address and is known to be nonzero. 12874 Handle warnings about undefined signed overflow. */ 12875 12876bool 12877tree_expr_nonzero_p (tree t) 12878{ 12879 bool ret, strict_overflow_p; 12880 12881 strict_overflow_p = false; 12882 ret = tree_expr_nonzero_warnv_p (t, &strict_overflow_p); 12883 if (strict_overflow_p) 12884 fold_overflow_warning (("assuming signed overflow does not occur when " 12885 "determining that expression is always " 12886 "non-zero"), 12887 WARN_STRICT_OVERFLOW_MISC); 12888 return ret; 12889} 12890 12891/* Given the components of a binary expression CODE, TYPE, OP0 and OP1, 12892 attempt to fold the expression to a constant without modifying TYPE, 12893 OP0 or OP1. 12894 12895 If the expression could be simplified to a constant, then return 12896 the constant. If the expression would not be simplified to a 12897 constant, then return NULL_TREE. */ 12898 12899tree 12900fold_binary_to_constant (enum tree_code code, tree type, tree op0, tree op1) 12901{ 12902 tree tem = fold_binary (code, type, op0, op1); 12903 return (tem && TREE_CONSTANT (tem)) ? tem : NULL_TREE; 12904} 12905 12906/* Given the components of a unary expression CODE, TYPE and OP0, 12907 attempt to fold the expression to a constant without modifying 12908 TYPE or OP0. 12909 12910 If the expression could be simplified to a constant, then return 12911 the constant. If the expression would not be simplified to a 12912 constant, then return NULL_TREE. */ 12913 12914tree 12915fold_unary_to_constant (enum tree_code code, tree type, tree op0) 12916{ 12917 tree tem = fold_unary (code, type, op0); 12918 return (tem && TREE_CONSTANT (tem)) ? tem : NULL_TREE; 12919} 12920 12921/* If EXP represents referencing an element in a constant string 12922 (either via pointer arithmetic or array indexing), return the 12923 tree representing the value accessed, otherwise return NULL. */ 12924 12925tree 12926fold_read_from_constant_string (tree exp) 12927{ 12928 if ((TREE_CODE (exp) == INDIRECT_REF 12929 || TREE_CODE (exp) == ARRAY_REF) 12930 && TREE_CODE (TREE_TYPE (exp)) == INTEGER_TYPE) 12931 { 12932 tree exp1 = TREE_OPERAND (exp, 0); 12933 tree index; 12934 tree string; 12935 12936 if (TREE_CODE (exp) == INDIRECT_REF) 12937 string = string_constant (exp1, &index); 12938 else 12939 { 12940 tree low_bound = array_ref_low_bound (exp); 12941 index = fold_convert (sizetype, TREE_OPERAND (exp, 1)); 12942 12943 /* Optimize the special-case of a zero lower bound. 12944 12945 We convert the low_bound to sizetype to avoid some problems 12946 with constant folding. (E.g. suppose the lower bound is 1, 12947 and its mode is QI. Without the conversion,l (ARRAY 12948 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1)) 12949 +INDEX), which becomes (ARRAY+255+INDEX). Opps!) */ 12950 if (! integer_zerop (low_bound)) 12951 index = size_diffop (index, fold_convert (sizetype, low_bound)); 12952 12953 string = exp1; 12954 } 12955 12956 if (string 12957 && TYPE_MODE (TREE_TYPE (exp)) == TYPE_MODE (TREE_TYPE (TREE_TYPE (string))) 12958 && TREE_CODE (string) == STRING_CST 12959 && TREE_CODE (index) == INTEGER_CST 12960 && compare_tree_int (index, TREE_STRING_LENGTH (string)) < 0 12961 && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (string)))) 12962 == MODE_INT) 12963 && (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (string)))) == 1)) 12964 return fold_convert (TREE_TYPE (exp), 12965 build_int_cst (NULL_TREE, 12966 (TREE_STRING_POINTER (string) 12967 [TREE_INT_CST_LOW (index)]))); 12968 } 12969 return NULL; 12970} 12971 12972/* Return the tree for neg (ARG0) when ARG0 is known to be either 12973 an integer constant or real constant. 12974 12975 TYPE is the type of the result. */ 12976 12977static tree 12978fold_negate_const (tree arg0, tree type) 12979{ 12980 tree t = NULL_TREE; 12981 12982 switch (TREE_CODE (arg0)) 12983 { 12984 case INTEGER_CST: 12985 { 12986 unsigned HOST_WIDE_INT low; 12987 HOST_WIDE_INT high; 12988 int overflow = neg_double (TREE_INT_CST_LOW (arg0), 12989 TREE_INT_CST_HIGH (arg0), 12990 &low, &high); 12991 t = build_int_cst_wide (type, low, high); 12992 t = force_fit_type (t, 1, 12993 (overflow | TREE_OVERFLOW (arg0)) 12994 && !TYPE_UNSIGNED (type), 12995 TREE_CONSTANT_OVERFLOW (arg0)); 12996 break; 12997 } 12998 12999 case REAL_CST: 13000 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0))); 13001 break; 13002 13003 default: 13004 gcc_unreachable (); 13005 } 13006 13007 return t; 13008} 13009 13010/* Return the tree for abs (ARG0) when ARG0 is known to be either 13011 an integer constant or real constant. 13012 13013 TYPE is the type of the result. */ 13014 13015tree 13016fold_abs_const (tree arg0, tree type) 13017{ 13018 tree t = NULL_TREE; 13019 13020 switch (TREE_CODE (arg0)) 13021 { 13022 case INTEGER_CST: 13023 /* If the value is unsigned, then the absolute value is 13024 the same as the ordinary value. */ 13025 if (TYPE_UNSIGNED (type)) 13026 t = arg0; 13027 /* Similarly, if the value is non-negative. */ 13028 else if (INT_CST_LT (integer_minus_one_node, arg0)) 13029 t = arg0; 13030 /* If the value is negative, then the absolute value is 13031 its negation. */ 13032 else 13033 { 13034 unsigned HOST_WIDE_INT low; 13035 HOST_WIDE_INT high; 13036 int overflow = neg_double (TREE_INT_CST_LOW (arg0), 13037 TREE_INT_CST_HIGH (arg0), 13038 &low, &high); 13039 t = build_int_cst_wide (type, low, high); 13040 t = force_fit_type (t, -1, overflow | TREE_OVERFLOW (arg0), 13041 TREE_CONSTANT_OVERFLOW (arg0)); 13042 } 13043 break; 13044 13045 case REAL_CST: 13046 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0))) 13047 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0))); 13048 else 13049 t = arg0; 13050 break; 13051 13052 default: 13053 gcc_unreachable (); 13054 } 13055 13056 return t; 13057} 13058 13059/* Return the tree for not (ARG0) when ARG0 is known to be an integer 13060 constant. TYPE is the type of the result. */ 13061 13062static tree 13063fold_not_const (tree arg0, tree type) 13064{ 13065 tree t = NULL_TREE; 13066 13067 gcc_assert (TREE_CODE (arg0) == INTEGER_CST); 13068 13069 t = build_int_cst_wide (type, 13070 ~ TREE_INT_CST_LOW (arg0), 13071 ~ TREE_INT_CST_HIGH (arg0)); 13072 t = force_fit_type (t, 0, TREE_OVERFLOW (arg0), 13073 TREE_CONSTANT_OVERFLOW (arg0)); 13074 13075 return t; 13076} 13077 13078/* Given CODE, a relational operator, the target type, TYPE and two 13079 constant operands OP0 and OP1, return the result of the 13080 relational operation. If the result is not a compile time 13081 constant, then return NULL_TREE. */ 13082 13083static tree 13084fold_relational_const (enum tree_code code, tree type, tree op0, tree op1) 13085{ 13086 int result, invert; 13087 13088 /* From here on, the only cases we handle are when the result is 13089 known to be a constant. */ 13090 13091 if (TREE_CODE (op0) == REAL_CST && TREE_CODE (op1) == REAL_CST) 13092 { 13093 const REAL_VALUE_TYPE *c0 = TREE_REAL_CST_PTR (op0); 13094 const REAL_VALUE_TYPE *c1 = TREE_REAL_CST_PTR (op1); 13095 13096 /* Handle the cases where either operand is a NaN. */ 13097 if (real_isnan (c0) || real_isnan (c1)) 13098 { 13099 switch (code) 13100 { 13101 case EQ_EXPR: 13102 case ORDERED_EXPR: 13103 result = 0; 13104 break; 13105 13106 case NE_EXPR: 13107 case UNORDERED_EXPR: 13108 case UNLT_EXPR: 13109 case UNLE_EXPR: 13110 case UNGT_EXPR: 13111 case UNGE_EXPR: 13112 case UNEQ_EXPR: 13113 result = 1; 13114 break; 13115 13116 case LT_EXPR: 13117 case LE_EXPR: 13118 case GT_EXPR: 13119 case GE_EXPR: 13120 case LTGT_EXPR: 13121 if (flag_trapping_math) 13122 return NULL_TREE; 13123 result = 0; 13124 break; 13125 13126 default: 13127 gcc_unreachable (); 13128 } 13129 13130 return constant_boolean_node (result, type); 13131 } 13132 13133 return constant_boolean_node (real_compare (code, c0, c1), type); 13134 } 13135 13136 /* Handle equality/inequality of complex constants. */ 13137 if (TREE_CODE (op0) == COMPLEX_CST && TREE_CODE (op1) == COMPLEX_CST) 13138 { 13139 tree rcond = fold_relational_const (code, type, 13140 TREE_REALPART (op0), 13141 TREE_REALPART (op1)); 13142 tree icond = fold_relational_const (code, type, 13143 TREE_IMAGPART (op0), 13144 TREE_IMAGPART (op1)); 13145 if (code == EQ_EXPR) 13146 return fold_build2 (TRUTH_ANDIF_EXPR, type, rcond, icond); 13147 else if (code == NE_EXPR) 13148 return fold_build2 (TRUTH_ORIF_EXPR, type, rcond, icond); 13149 else 13150 return NULL_TREE; 13151 } 13152 13153 /* From here on we only handle LT, LE, GT, GE, EQ and NE. 13154 13155 To compute GT, swap the arguments and do LT. 13156 To compute GE, do LT and invert the result. 13157 To compute LE, swap the arguments, do LT and invert the result. 13158 To compute NE, do EQ and invert the result. 13159 13160 Therefore, the code below must handle only EQ and LT. */ 13161 13162 if (code == LE_EXPR || code == GT_EXPR) 13163 { 13164 tree tem = op0; 13165 op0 = op1; 13166 op1 = tem; 13167 code = swap_tree_comparison (code); 13168 } 13169 13170 /* Note that it is safe to invert for real values here because we 13171 have already handled the one case that it matters. */ 13172 13173 invert = 0; 13174 if (code == NE_EXPR || code == GE_EXPR) 13175 { 13176 invert = 1; 13177 code = invert_tree_comparison (code, false); 13178 } 13179 13180 /* Compute a result for LT or EQ if args permit; 13181 Otherwise return T. */ 13182 if (TREE_CODE (op0) == INTEGER_CST && TREE_CODE (op1) == INTEGER_CST) 13183 { 13184 if (code == EQ_EXPR) 13185 result = tree_int_cst_equal (op0, op1); 13186 else if (TYPE_UNSIGNED (TREE_TYPE (op0))) 13187 result = INT_CST_LT_UNSIGNED (op0, op1); 13188 else 13189 result = INT_CST_LT (op0, op1); 13190 } 13191 else 13192 return NULL_TREE; 13193 13194 if (invert) 13195 result ^= 1; 13196 return constant_boolean_node (result, type); 13197} 13198 13199/* Build an expression for the a clean point containing EXPR with type TYPE. 13200 Don't build a cleanup point expression for EXPR which don't have side 13201 effects. */ 13202 13203tree 13204fold_build_cleanup_point_expr (tree type, tree expr) 13205{ 13206 /* If the expression does not have side effects then we don't have to wrap 13207 it with a cleanup point expression. */ 13208 if (!TREE_SIDE_EFFECTS (expr)) 13209 return expr; 13210 13211 /* If the expression is a return, check to see if the expression inside the 13212 return has no side effects or the right hand side of the modify expression 13213 inside the return. If either don't have side effects set we don't need to 13214 wrap the expression in a cleanup point expression. Note we don't check the 13215 left hand side of the modify because it should always be a return decl. */ 13216 if (TREE_CODE (expr) == RETURN_EXPR) 13217 { 13218 tree op = TREE_OPERAND (expr, 0); 13219 if (!op || !TREE_SIDE_EFFECTS (op)) 13220 return expr; 13221 op = TREE_OPERAND (op, 1); 13222 if (!TREE_SIDE_EFFECTS (op)) 13223 return expr; 13224 } 13225 13226 return build1 (CLEANUP_POINT_EXPR, type, expr); 13227} 13228 13229/* Build an expression for the address of T. Folds away INDIRECT_REF to 13230 avoid confusing the gimplify process. */ 13231 13232tree 13233build_fold_addr_expr_with_type (tree t, tree ptrtype) 13234{ 13235 /* The size of the object is not relevant when talking about its address. */ 13236 if (TREE_CODE (t) == WITH_SIZE_EXPR) 13237 t = TREE_OPERAND (t, 0); 13238 13239 /* Note: doesn't apply to ALIGN_INDIRECT_REF */ 13240 if (TREE_CODE (t) == INDIRECT_REF 13241 || TREE_CODE (t) == MISALIGNED_INDIRECT_REF) 13242 { 13243 t = TREE_OPERAND (t, 0); 13244 if (TREE_TYPE (t) != ptrtype) 13245 t = build1 (NOP_EXPR, ptrtype, t); 13246 } 13247 else 13248 { 13249 tree base = t; 13250 13251 while (handled_component_p (base)) 13252 base = TREE_OPERAND (base, 0); 13253 if (DECL_P (base)) 13254 TREE_ADDRESSABLE (base) = 1; 13255 13256 t = build1 (ADDR_EXPR, ptrtype, t); 13257 } 13258 13259 return t; 13260} 13261 13262tree 13263build_fold_addr_expr (tree t) 13264{ 13265 return build_fold_addr_expr_with_type (t, build_pointer_type (TREE_TYPE (t))); 13266} 13267 13268/* Given a pointer value OP0 and a type TYPE, return a simplified version 13269 of an indirection through OP0, or NULL_TREE if no simplification is 13270 possible. */ 13271 13272tree 13273fold_indirect_ref_1 (tree type, tree op0) 13274{ 13275 tree sub = op0; 13276 tree subtype; 13277 13278 STRIP_NOPS (sub); 13279 subtype = TREE_TYPE (sub); 13280 if (!POINTER_TYPE_P (subtype)) 13281 return NULL_TREE; 13282 13283 if (TREE_CODE (sub) == ADDR_EXPR) 13284 { 13285 tree op = TREE_OPERAND (sub, 0); 13286 tree optype = TREE_TYPE (op); 13287 /* *&CONST_DECL -> to the value of the const decl. */ 13288 if (TREE_CODE (op) == CONST_DECL) 13289 return DECL_INITIAL (op); 13290 /* *&p => p; make sure to handle *&"str"[cst] here. */ 13291 if (type == optype) 13292 { 13293 tree fop = fold_read_from_constant_string (op); 13294 if (fop) 13295 return fop; 13296 else 13297 return op; 13298 } 13299 /* *(foo *)&fooarray => fooarray[0] */ 13300 else if (TREE_CODE (optype) == ARRAY_TYPE 13301 && type == TREE_TYPE (optype)) 13302 { 13303 tree type_domain = TYPE_DOMAIN (optype); 13304 tree min_val = size_zero_node; 13305 if (type_domain && TYPE_MIN_VALUE (type_domain)) 13306 min_val = TYPE_MIN_VALUE (type_domain); 13307 return build4 (ARRAY_REF, type, op, min_val, NULL_TREE, NULL_TREE); 13308 } 13309 /* *(foo *)&complexfoo => __real__ complexfoo */ 13310 else if (TREE_CODE (optype) == COMPLEX_TYPE 13311 && type == TREE_TYPE (optype)) 13312 return fold_build1 (REALPART_EXPR, type, op); 13313 } 13314 13315 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ 13316 if (TREE_CODE (sub) == PLUS_EXPR 13317 && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST) 13318 { 13319 tree op00 = TREE_OPERAND (sub, 0); 13320 tree op01 = TREE_OPERAND (sub, 1); 13321 tree op00type; 13322 13323 STRIP_NOPS (op00); 13324 op00type = TREE_TYPE (op00); 13325 if (TREE_CODE (op00) == ADDR_EXPR 13326 && TREE_CODE (TREE_TYPE (op00type)) == COMPLEX_TYPE 13327 && type == TREE_TYPE (TREE_TYPE (op00type))) 13328 { 13329 tree size = TYPE_SIZE_UNIT (type); 13330 if (tree_int_cst_equal (size, op01)) 13331 return fold_build1 (IMAGPART_EXPR, type, TREE_OPERAND (op00, 0)); 13332 } 13333 } 13334 13335 /* *(foo *)fooarrptr => (*fooarrptr)[0] */ 13336 if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE 13337 && type == TREE_TYPE (TREE_TYPE (subtype))) 13338 { 13339 tree type_domain; 13340 tree min_val = size_zero_node; 13341 sub = build_fold_indirect_ref (sub); 13342 type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); 13343 if (type_domain && TYPE_MIN_VALUE (type_domain)) 13344 min_val = TYPE_MIN_VALUE (type_domain); 13345 return build4 (ARRAY_REF, type, sub, min_val, NULL_TREE, NULL_TREE); 13346 } 13347 13348 return NULL_TREE; 13349} 13350 13351/* Builds an expression for an indirection through T, simplifying some 13352 cases. */ 13353 13354tree 13355build_fold_indirect_ref (tree t) 13356{ 13357 tree type = TREE_TYPE (TREE_TYPE (t)); 13358 tree sub = fold_indirect_ref_1 (type, t); 13359 13360 if (sub) 13361 return sub; 13362 else 13363 return build1 (INDIRECT_REF, type, t); 13364} 13365 13366/* Given an INDIRECT_REF T, return either T or a simplified version. */ 13367 13368tree 13369fold_indirect_ref (tree t) 13370{ 13371 tree sub = fold_indirect_ref_1 (TREE_TYPE (t), TREE_OPERAND (t, 0)); 13372 13373 if (sub) 13374 return sub; 13375 else 13376 return t; 13377} 13378 13379/* Strip non-trapping, non-side-effecting tree nodes from an expression 13380 whose result is ignored. The type of the returned tree need not be 13381 the same as the original expression. */ 13382 13383tree 13384fold_ignored_result (tree t) 13385{ 13386 if (!TREE_SIDE_EFFECTS (t)) 13387 return integer_zero_node; 13388 13389 for (;;) 13390 switch (TREE_CODE_CLASS (TREE_CODE (t))) 13391 { 13392 case tcc_unary: 13393 t = TREE_OPERAND (t, 0); 13394 break; 13395 13396 case tcc_binary: 13397 case tcc_comparison: 13398 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (t, 1))) 13399 t = TREE_OPERAND (t, 0); 13400 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (t, 0))) 13401 t = TREE_OPERAND (t, 1); 13402 else 13403 return t; 13404 break; 13405 13406 case tcc_expression: 13407 switch (TREE_CODE (t)) 13408 { 13409 case COMPOUND_EXPR: 13410 if (TREE_SIDE_EFFECTS (TREE_OPERAND (t, 1))) 13411 return t; 13412 t = TREE_OPERAND (t, 0); 13413 break; 13414 13415 case COND_EXPR: 13416 if (TREE_SIDE_EFFECTS (TREE_OPERAND (t, 1)) 13417 || TREE_SIDE_EFFECTS (TREE_OPERAND (t, 2))) 13418 return t; 13419 t = TREE_OPERAND (t, 0); 13420 break; 13421 13422 default: 13423 return t; 13424 } 13425 break; 13426 13427 default: 13428 return t; 13429 } 13430} 13431 13432/* Return the value of VALUE, rounded up to a multiple of DIVISOR. 13433 This can only be applied to objects of a sizetype. */ 13434 13435tree 13436round_up (tree value, int divisor) 13437{ 13438 tree div = NULL_TREE; 13439 13440 gcc_assert (divisor > 0); 13441 if (divisor == 1) 13442 return value; 13443 13444 /* See if VALUE is already a multiple of DIVISOR. If so, we don't 13445 have to do anything. Only do this when we are not given a const, 13446 because in that case, this check is more expensive than just 13447 doing it. */ 13448 if (TREE_CODE (value) != INTEGER_CST) 13449 { 13450 div = build_int_cst (TREE_TYPE (value), divisor); 13451 13452 if (multiple_of_p (TREE_TYPE (value), value, div)) 13453 return value; 13454 } 13455 13456 /* If divisor is a power of two, simplify this to bit manipulation. */ 13457 if (divisor == (divisor & -divisor)) 13458 { 13459 tree t; 13460 13461 t = build_int_cst (TREE_TYPE (value), divisor - 1); 13462 value = size_binop (PLUS_EXPR, value, t); 13463 t = build_int_cst (TREE_TYPE (value), -divisor); 13464 value = size_binop (BIT_AND_EXPR, value, t); 13465 } 13466 else 13467 { 13468 if (!div) 13469 div = build_int_cst (TREE_TYPE (value), divisor); 13470 value = size_binop (CEIL_DIV_EXPR, value, div); 13471 value = size_binop (MULT_EXPR, value, div); 13472 } 13473 13474 return value; 13475} 13476 13477/* Likewise, but round down. */ 13478 13479tree 13480round_down (tree value, int divisor) 13481{ 13482 tree div = NULL_TREE; 13483 13484 gcc_assert (divisor > 0); 13485 if (divisor == 1) 13486 return value; 13487 13488 /* See if VALUE is already a multiple of DIVISOR. If so, we don't 13489 have to do anything. Only do this when we are not given a const, 13490 because in that case, this check is more expensive than just 13491 doing it. */ 13492 if (TREE_CODE (value) != INTEGER_CST) 13493 { 13494 div = build_int_cst (TREE_TYPE (value), divisor); 13495 13496 if (multiple_of_p (TREE_TYPE (value), value, div)) 13497 return value; 13498 } 13499 13500 /* If divisor is a power of two, simplify this to bit manipulation. */ 13501 if (divisor == (divisor & -divisor)) 13502 { 13503 tree t; 13504 13505 t = build_int_cst (TREE_TYPE (value), -divisor); 13506 value = size_binop (BIT_AND_EXPR, value, t); 13507 } 13508 else 13509 { 13510 if (!div) 13511 div = build_int_cst (TREE_TYPE (value), divisor); 13512 value = size_binop (FLOOR_DIV_EXPR, value, div); 13513 value = size_binop (MULT_EXPR, value, div); 13514 } 13515 13516 return value; 13517} 13518 13519/* Returns the pointer to the base of the object addressed by EXP and 13520 extracts the information about the offset of the access, storing it 13521 to PBITPOS and POFFSET. */ 13522 13523static tree 13524split_address_to_core_and_offset (tree exp, 13525 HOST_WIDE_INT *pbitpos, tree *poffset) 13526{ 13527 tree core; 13528 enum machine_mode mode; 13529 int unsignedp, volatilep; 13530 HOST_WIDE_INT bitsize; 13531 13532 if (TREE_CODE (exp) == ADDR_EXPR) 13533 { 13534 core = get_inner_reference (TREE_OPERAND (exp, 0), &bitsize, pbitpos, 13535 poffset, &mode, &unsignedp, &volatilep, 13536 false); 13537 core = build_fold_addr_expr (core); 13538 } 13539 else 13540 { 13541 core = exp; 13542 *pbitpos = 0; 13543 *poffset = NULL_TREE; 13544 } 13545 13546 return core; 13547} 13548 13549/* Returns true if addresses of E1 and E2 differ by a constant, false 13550 otherwise. If they do, E1 - E2 is stored in *DIFF. */ 13551 13552bool 13553ptr_difference_const (tree e1, tree e2, HOST_WIDE_INT *diff) 13554{ 13555 tree core1, core2; 13556 HOST_WIDE_INT bitpos1, bitpos2; 13557 tree toffset1, toffset2, tdiff, type; 13558 13559 core1 = split_address_to_core_and_offset (e1, &bitpos1, &toffset1); 13560 core2 = split_address_to_core_and_offset (e2, &bitpos2, &toffset2); 13561 13562 if (bitpos1 % BITS_PER_UNIT != 0 13563 || bitpos2 % BITS_PER_UNIT != 0 13564 || !operand_equal_p (core1, core2, 0)) 13565 return false; 13566 13567 if (toffset1 && toffset2) 13568 { 13569 type = TREE_TYPE (toffset1); 13570 if (type != TREE_TYPE (toffset2)) 13571 toffset2 = fold_convert (type, toffset2); 13572 13573 tdiff = fold_build2 (MINUS_EXPR, type, toffset1, toffset2); 13574 if (!cst_and_fits_in_hwi (tdiff)) 13575 return false; 13576 13577 *diff = int_cst_value (tdiff); 13578 } 13579 else if (toffset1 || toffset2) 13580 { 13581 /* If only one of the offsets is non-constant, the difference cannot 13582 be a constant. */ 13583 return false; 13584 } 13585 else 13586 *diff = 0; 13587 13588 *diff += (bitpos1 - bitpos2) / BITS_PER_UNIT; 13589 return true; 13590} 13591 13592/* Simplify the floating point expression EXP when the sign of the 13593 result is not significant. Return NULL_TREE if no simplification 13594 is possible. */ 13595 13596tree 13597fold_strip_sign_ops (tree exp) 13598{ 13599 tree arg0, arg1; 13600 13601 switch (TREE_CODE (exp)) 13602 { 13603 case ABS_EXPR: 13604 case NEGATE_EXPR: 13605 arg0 = fold_strip_sign_ops (TREE_OPERAND (exp, 0)); 13606 return arg0 ? arg0 : TREE_OPERAND (exp, 0); 13607 13608 case MULT_EXPR: 13609 case RDIV_EXPR: 13610 if (HONOR_SIGN_DEPENDENT_ROUNDING (TYPE_MODE (TREE_TYPE (exp)))) 13611 return NULL_TREE; 13612 arg0 = fold_strip_sign_ops (TREE_OPERAND (exp, 0)); 13613 arg1 = fold_strip_sign_ops (TREE_OPERAND (exp, 1)); 13614 if (arg0 != NULL_TREE || arg1 != NULL_TREE) 13615 return fold_build2 (TREE_CODE (exp), TREE_TYPE (exp), 13616 arg0 ? arg0 : TREE_OPERAND (exp, 0), 13617 arg1 ? arg1 : TREE_OPERAND (exp, 1)); 13618 break; 13619 13620 default: 13621 break; 13622 } 13623 return NULL_TREE; 13624} 13625 13626