1/* Convert tree expression to rtl instructions, for GNU compiler. 2 Copyright (C) 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 3 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 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 3, 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 COPYING3. If not see 20<http://www.gnu.org/licenses/>. */ 21 22#include "config.h" 23#include "system.h" 24#include "coretypes.h" 25#include "tm.h" 26#include "rtl.h" 27#include "tree.h" 28#include "flags.h" 29#include "function.h" 30#include "insn-config.h" 31#include "insn-attr.h" 32/* Include expr.h after insn-config.h so we get HAVE_conditional_move. */ 33#include "expr.h" 34#include "optabs.h" 35#include "langhooks.h" 36#include "ggc.h" 37#include "basic-block.h" 38#include "output.h" 39 40static bool prefer_and_bit_test (enum machine_mode, int); 41static void do_jump_by_parts_greater (tree, tree, int, rtx, rtx, int); 42static void do_jump_by_parts_equality (tree, tree, rtx, rtx, int); 43static void do_compare_and_jump (tree, tree, enum rtx_code, enum rtx_code, rtx, 44 rtx, int); 45 46/* Invert probability if there is any. -1 stands for unknown. */ 47 48static inline int 49inv (int prob) 50{ 51 return prob == -1 ? -1 : REG_BR_PROB_BASE - prob; 52} 53 54/* At the start of a function, record that we have no previously-pushed 55 arguments waiting to be popped. */ 56 57void 58init_pending_stack_adjust (void) 59{ 60 pending_stack_adjust = 0; 61} 62 63/* Discard any pending stack adjustment. This avoid relying on the 64 RTL optimizers to remove useless adjustments when we know the 65 stack pointer value is dead. */ 66void 67discard_pending_stack_adjust (void) 68{ 69 stack_pointer_delta -= pending_stack_adjust; 70 pending_stack_adjust = 0; 71} 72 73/* When exiting from function, if safe, clear out any pending stack adjust 74 so the adjustment won't get done. 75 76 Note, if the current function calls alloca, then it must have a 77 frame pointer regardless of the value of flag_omit_frame_pointer. */ 78 79void 80clear_pending_stack_adjust (void) 81{ 82 if (optimize > 0 83 && (! flag_omit_frame_pointer || cfun->calls_alloca) 84 && EXIT_IGNORE_STACK) 85 discard_pending_stack_adjust (); 86} 87 88/* Pop any previously-pushed arguments that have not been popped yet. */ 89 90void 91do_pending_stack_adjust (void) 92{ 93 if (inhibit_defer_pop == 0) 94 { 95 if (pending_stack_adjust != 0) 96 adjust_stack (GEN_INT (pending_stack_adjust)); 97 pending_stack_adjust = 0; 98 } 99} 100 101/* Expand conditional expressions. */ 102 103/* Generate code to evaluate EXP and jump to LABEL if the value is zero. 104 LABEL is an rtx of code CODE_LABEL, in this function and all the 105 functions here. */ 106 107void 108jumpifnot (tree exp, rtx label, int prob) 109{ 110 do_jump (exp, label, NULL_RTX, inv (prob)); 111} 112 113void 114jumpifnot_1 (enum tree_code code, tree op0, tree op1, rtx label, int prob) 115{ 116 do_jump_1 (code, op0, op1, label, NULL_RTX, inv (prob)); 117} 118 119/* Generate code to evaluate EXP and jump to LABEL if the value is nonzero. */ 120 121void 122jumpif (tree exp, rtx label, int prob) 123{ 124 do_jump (exp, NULL_RTX, label, prob); 125} 126 127void 128jumpif_1 (enum tree_code code, tree op0, tree op1, rtx label, int prob) 129{ 130 do_jump_1 (code, op0, op1, NULL_RTX, label, prob); 131} 132 133/* Used internally by prefer_and_bit_test. */ 134 135static GTY(()) rtx and_reg; 136static GTY(()) rtx and_test; 137static GTY(()) rtx shift_test; 138 139/* Compare the relative costs of "(X & (1 << BITNUM))" and "(X >> BITNUM) & 1", 140 where X is an arbitrary register of mode MODE. Return true if the former 141 is preferred. */ 142 143static bool 144prefer_and_bit_test (enum machine_mode mode, int bitnum) 145{ 146 if (and_test == 0) 147 { 148 /* Set up rtxes for the two variations. Use NULL as a placeholder 149 for the BITNUM-based constants. */ 150 and_reg = gen_rtx_REG (mode, FIRST_PSEUDO_REGISTER); 151 and_test = gen_rtx_AND (mode, and_reg, NULL); 152 shift_test = gen_rtx_AND (mode, gen_rtx_ASHIFTRT (mode, and_reg, NULL), 153 const1_rtx); 154 } 155 else 156 { 157 /* Change the mode of the previously-created rtxes. */ 158 PUT_MODE (and_reg, mode); 159 PUT_MODE (and_test, mode); 160 PUT_MODE (shift_test, mode); 161 PUT_MODE (XEXP (shift_test, 0), mode); 162 } 163 164 /* Fill in the integers. */ 165 XEXP (and_test, 1) 166 = immed_double_const ((unsigned HOST_WIDE_INT) 1 << bitnum, 0, mode); 167 XEXP (XEXP (shift_test, 0), 1) = GEN_INT (bitnum); 168 169 return (rtx_cost (and_test, IF_THEN_ELSE, optimize_insn_for_speed_p ()) 170 <= rtx_cost (shift_test, IF_THEN_ELSE, optimize_insn_for_speed_p ())); 171} 172 173/* Subroutine of do_jump, dealing with exploded comparisons of the type 174 OP0 CODE OP1 . IF_FALSE_LABEL and IF_TRUE_LABEL like in do_jump. 175 PROB is probability of jump to if_true_label, or -1 if unknown. */ 176 177void 178do_jump_1 (enum tree_code code, tree op0, tree op1, 179 rtx if_false_label, rtx if_true_label, int prob) 180{ 181 enum machine_mode mode; 182 rtx drop_through_label = 0; 183 184 switch (code) 185 { 186 case EQ_EXPR: 187 { 188 tree inner_type = TREE_TYPE (op0); 189 190 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type)) 191 != MODE_COMPLEX_FLOAT); 192 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type)) 193 != MODE_COMPLEX_INT); 194 195 if (integer_zerop (op1)) 196 do_jump (op0, if_true_label, if_false_label, inv (prob)); 197 else if (GET_MODE_CLASS (TYPE_MODE (inner_type)) == MODE_INT 198 && !can_compare_p (EQ, TYPE_MODE (inner_type), ccp_jump)) 199 do_jump_by_parts_equality (op0, op1, if_false_label, if_true_label, 200 prob); 201 else 202 do_compare_and_jump (op0, op1, EQ, EQ, if_false_label, if_true_label, 203 prob); 204 break; 205 } 206 207 case NE_EXPR: 208 { 209 tree inner_type = TREE_TYPE (op0); 210 211 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type)) 212 != MODE_COMPLEX_FLOAT); 213 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type)) 214 != MODE_COMPLEX_INT); 215 216 if (integer_zerop (op1)) 217 do_jump (op0, if_false_label, if_true_label, prob); 218 else if (GET_MODE_CLASS (TYPE_MODE (inner_type)) == MODE_INT 219 && !can_compare_p (NE, TYPE_MODE (inner_type), ccp_jump)) 220 do_jump_by_parts_equality (op0, op1, if_true_label, if_false_label, 221 inv (prob)); 222 else 223 do_compare_and_jump (op0, op1, NE, NE, if_false_label, if_true_label, 224 prob); 225 break; 226 } 227 228 case LT_EXPR: 229 mode = TYPE_MODE (TREE_TYPE (op0)); 230 if (GET_MODE_CLASS (mode) == MODE_INT 231 && ! can_compare_p (LT, mode, ccp_jump)) 232 do_jump_by_parts_greater (op0, op1, 1, if_false_label, if_true_label, 233 prob); 234 else 235 do_compare_and_jump (op0, op1, LT, LTU, if_false_label, if_true_label, 236 prob); 237 break; 238 239 case LE_EXPR: 240 mode = TYPE_MODE (TREE_TYPE (op0)); 241 if (GET_MODE_CLASS (mode) == MODE_INT 242 && ! can_compare_p (LE, mode, ccp_jump)) 243 do_jump_by_parts_greater (op0, op1, 0, if_true_label, if_false_label, 244 inv (prob)); 245 else 246 do_compare_and_jump (op0, op1, LE, LEU, if_false_label, if_true_label, 247 prob); 248 break; 249 250 case GT_EXPR: 251 mode = TYPE_MODE (TREE_TYPE (op0)); 252 if (GET_MODE_CLASS (mode) == MODE_INT 253 && ! can_compare_p (GT, mode, ccp_jump)) 254 do_jump_by_parts_greater (op0, op1, 0, if_false_label, if_true_label, 255 prob); 256 else 257 do_compare_and_jump (op0, op1, GT, GTU, if_false_label, if_true_label, 258 prob); 259 break; 260 261 case GE_EXPR: 262 mode = TYPE_MODE (TREE_TYPE (op0)); 263 if (GET_MODE_CLASS (mode) == MODE_INT 264 && ! can_compare_p (GE, mode, ccp_jump)) 265 do_jump_by_parts_greater (op0, op1, 1, if_true_label, if_false_label, 266 inv (prob)); 267 else 268 do_compare_and_jump (op0, op1, GE, GEU, if_false_label, if_true_label, 269 prob); 270 break; 271 272 case ORDERED_EXPR: 273 do_compare_and_jump (op0, op1, ORDERED, ORDERED, 274 if_false_label, if_true_label, prob); 275 break; 276 277 case UNORDERED_EXPR: 278 do_compare_and_jump (op0, op1, UNORDERED, UNORDERED, 279 if_false_label, if_true_label, prob); 280 break; 281 282 case UNLT_EXPR: 283 do_compare_and_jump (op0, op1, UNLT, UNLT, if_false_label, if_true_label, 284 prob); 285 break; 286 287 case UNLE_EXPR: 288 do_compare_and_jump (op0, op1, UNLE, UNLE, if_false_label, if_true_label, 289 prob); 290 break; 291 292 case UNGT_EXPR: 293 do_compare_and_jump (op0, op1, UNGT, UNGT, if_false_label, if_true_label, 294 prob); 295 break; 296 297 case UNGE_EXPR: 298 do_compare_and_jump (op0, op1, UNGE, UNGE, if_false_label, if_true_label, 299 prob); 300 break; 301 302 case UNEQ_EXPR: 303 do_compare_and_jump (op0, op1, UNEQ, UNEQ, if_false_label, if_true_label, 304 prob); 305 break; 306 307 case LTGT_EXPR: 308 do_compare_and_jump (op0, op1, LTGT, LTGT, if_false_label, if_true_label, 309 prob); 310 break; 311 312 case TRUTH_ANDIF_EXPR: 313 if (if_false_label == NULL_RTX) 314 { 315 drop_through_label = gen_label_rtx (); 316 do_jump (op0, drop_through_label, NULL_RTX, prob); 317 do_jump (op1, NULL_RTX, if_true_label, prob); 318 } 319 else 320 { 321 do_jump (op0, if_false_label, NULL_RTX, prob); 322 do_jump (op1, if_false_label, if_true_label, prob); 323 } 324 break; 325 326 case TRUTH_ORIF_EXPR: 327 if (if_true_label == NULL_RTX) 328 { 329 drop_through_label = gen_label_rtx (); 330 do_jump (op0, NULL_RTX, drop_through_label, prob); 331 do_jump (op1, if_false_label, NULL_RTX, prob); 332 } 333 else 334 { 335 do_jump (op0, NULL_RTX, if_true_label, prob); 336 do_jump (op1, if_false_label, if_true_label, prob); 337 } 338 break; 339 340 default: 341 gcc_unreachable (); 342 } 343 344 if (drop_through_label) 345 { 346 do_pending_stack_adjust (); 347 emit_label (drop_through_label); 348 } 349} 350 351/* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if 352 the result is zero, or IF_TRUE_LABEL if the result is one. 353 Either of IF_FALSE_LABEL and IF_TRUE_LABEL may be zero, 354 meaning fall through in that case. 355 356 do_jump always does any pending stack adjust except when it does not 357 actually perform a jump. An example where there is no jump 358 is when EXP is `(foo (), 0)' and IF_FALSE_LABEL is null. 359 360 PROB is probability of jump to if_true_label, or -1 if unknown. */ 361 362void 363do_jump (tree exp, rtx if_false_label, rtx if_true_label, int prob) 364{ 365 enum tree_code code = TREE_CODE (exp); 366 rtx temp; 367 int i; 368 tree type; 369 enum machine_mode mode; 370 rtx drop_through_label = 0; 371 372 switch (code) 373 { 374 case ERROR_MARK: 375 break; 376 377 case INTEGER_CST: 378 temp = integer_zerop (exp) ? if_false_label : if_true_label; 379 if (temp) 380 emit_jump (temp); 381 break; 382 383#if 0 384 /* This is not true with #pragma weak */ 385 case ADDR_EXPR: 386 /* The address of something can never be zero. */ 387 if (if_true_label) 388 emit_jump (if_true_label); 389 break; 390#endif 391 392 case NOP_EXPR: 393 if (TREE_CODE (TREE_OPERAND (exp, 0)) == COMPONENT_REF 394 || TREE_CODE (TREE_OPERAND (exp, 0)) == BIT_FIELD_REF 395 || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_REF 396 || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_RANGE_REF) 397 goto normal; 398 case CONVERT_EXPR: 399 /* If we are narrowing the operand, we have to do the compare in the 400 narrower mode. */ 401 if ((TYPE_PRECISION (TREE_TYPE (exp)) 402 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp, 0))))) 403 goto normal; 404 case NON_LVALUE_EXPR: 405 case ABS_EXPR: 406 case NEGATE_EXPR: 407 case LROTATE_EXPR: 408 case RROTATE_EXPR: 409 /* These cannot change zero->nonzero or vice versa. */ 410 do_jump (TREE_OPERAND (exp, 0), if_false_label, if_true_label, prob); 411 break; 412 413 case TRUTH_NOT_EXPR: 414 do_jump (TREE_OPERAND (exp, 0), if_true_label, if_false_label, 415 inv (prob)); 416 break; 417 418 case COND_EXPR: 419 { 420 rtx label1 = gen_label_rtx (); 421 if (!if_true_label || !if_false_label) 422 { 423 drop_through_label = gen_label_rtx (); 424 if (!if_true_label) 425 if_true_label = drop_through_label; 426 if (!if_false_label) 427 if_false_label = drop_through_label; 428 } 429 430 do_pending_stack_adjust (); 431 do_jump (TREE_OPERAND (exp, 0), label1, NULL_RTX, -1); 432 do_jump (TREE_OPERAND (exp, 1), if_false_label, if_true_label, prob); 433 emit_label (label1); 434 do_jump (TREE_OPERAND (exp, 2), if_false_label, if_true_label, prob); 435 break; 436 } 437 438 case COMPOUND_EXPR: 439 /* Lowered by gimplify.c. */ 440 gcc_unreachable (); 441 442 case COMPONENT_REF: 443 case BIT_FIELD_REF: 444 case ARRAY_REF: 445 case ARRAY_RANGE_REF: 446 { 447 HOST_WIDE_INT bitsize, bitpos; 448 int unsignedp; 449 enum machine_mode mode; 450 tree type; 451 tree offset; 452 int volatilep = 0; 453 454 /* Get description of this reference. We don't actually care 455 about the underlying object here. */ 456 get_inner_reference (exp, &bitsize, &bitpos, &offset, &mode, 457 &unsignedp, &volatilep, false); 458 459 type = lang_hooks.types.type_for_size (bitsize, unsignedp); 460 if (! SLOW_BYTE_ACCESS 461 && type != 0 && bitsize >= 0 462 && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (exp)) 463 && have_insn_for (COMPARE, TYPE_MODE (type))) 464 { 465 do_jump (fold_convert (type, exp), if_false_label, if_true_label, 466 prob); 467 break; 468 } 469 goto normal; 470 } 471 472 case MINUS_EXPR: 473 /* Nonzero iff operands of minus differ. */ 474 code = NE_EXPR; 475 476 /* FALLTHRU */ 477 case EQ_EXPR: 478 case NE_EXPR: 479 case LT_EXPR: 480 case LE_EXPR: 481 case GT_EXPR: 482 case GE_EXPR: 483 case ORDERED_EXPR: 484 case UNORDERED_EXPR: 485 case UNLT_EXPR: 486 case UNLE_EXPR: 487 case UNGT_EXPR: 488 case UNGE_EXPR: 489 case UNEQ_EXPR: 490 case LTGT_EXPR: 491 case TRUTH_ANDIF_EXPR: 492 case TRUTH_ORIF_EXPR: 493 other_code: 494 do_jump_1 (code, TREE_OPERAND (exp, 0), TREE_OPERAND (exp, 1), 495 if_false_label, if_true_label, prob); 496 break; 497 498 case BIT_AND_EXPR: 499 /* fold_single_bit_test() converts (X & (1 << C)) into (X >> C) & 1. 500 See if the former is preferred for jump tests and restore it 501 if so. */ 502 if (integer_onep (TREE_OPERAND (exp, 1))) 503 { 504 tree exp0 = TREE_OPERAND (exp, 0); 505 rtx set_label, clr_label; 506 int setclr_prob = prob; 507 508 /* Strip narrowing integral type conversions. */ 509 while (CONVERT_EXPR_P (exp0) 510 && TREE_OPERAND (exp0, 0) != error_mark_node 511 && TYPE_PRECISION (TREE_TYPE (exp0)) 512 <= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp0, 0)))) 513 exp0 = TREE_OPERAND (exp0, 0); 514 515 /* "exp0 ^ 1" inverts the sense of the single bit test. */ 516 if (TREE_CODE (exp0) == BIT_XOR_EXPR 517 && integer_onep (TREE_OPERAND (exp0, 1))) 518 { 519 exp0 = TREE_OPERAND (exp0, 0); 520 clr_label = if_true_label; 521 set_label = if_false_label; 522 setclr_prob = inv (prob); 523 } 524 else 525 { 526 clr_label = if_false_label; 527 set_label = if_true_label; 528 } 529 530 if (TREE_CODE (exp0) == RSHIFT_EXPR) 531 { 532 tree arg = TREE_OPERAND (exp0, 0); 533 tree shift = TREE_OPERAND (exp0, 1); 534 tree argtype = TREE_TYPE (arg); 535 if (TREE_CODE (shift) == INTEGER_CST 536 && compare_tree_int (shift, 0) >= 0 537 && compare_tree_int (shift, HOST_BITS_PER_WIDE_INT) < 0 538 && prefer_and_bit_test (TYPE_MODE (argtype), 539 TREE_INT_CST_LOW (shift))) 540 { 541 unsigned HOST_WIDE_INT mask 542 = (unsigned HOST_WIDE_INT) 1 << TREE_INT_CST_LOW (shift); 543 do_jump (build2 (BIT_AND_EXPR, argtype, arg, 544 build_int_cst_wide_type (argtype, mask, 0)), 545 clr_label, set_label, setclr_prob); 546 break; 547 } 548 } 549 } 550 551 /* If we are AND'ing with a small constant, do this comparison in the 552 smallest type that fits. If the machine doesn't have comparisons 553 that small, it will be converted back to the wider comparison. 554 This helps if we are testing the sign bit of a narrower object. 555 combine can't do this for us because it can't know whether a 556 ZERO_EXTRACT or a compare in a smaller mode exists, but we do. */ 557 558 if (! SLOW_BYTE_ACCESS 559 && TREE_CODE (TREE_OPERAND (exp, 1)) == INTEGER_CST 560 && TYPE_PRECISION (TREE_TYPE (exp)) <= HOST_BITS_PER_WIDE_INT 561 && (i = tree_floor_log2 (TREE_OPERAND (exp, 1))) >= 0 562 && (mode = mode_for_size (i + 1, MODE_INT, 0)) != BLKmode 563 && (type = lang_hooks.types.type_for_mode (mode, 1)) != 0 564 && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (exp)) 565 && have_insn_for (COMPARE, TYPE_MODE (type))) 566 { 567 do_jump (fold_convert (type, exp), if_false_label, if_true_label, 568 prob); 569 break; 570 } 571 572 if (TYPE_PRECISION (TREE_TYPE (exp)) > 1 573 || TREE_CODE (TREE_OPERAND (exp, 1)) == INTEGER_CST) 574 goto normal; 575 576 /* Boolean comparisons can be compiled as TRUTH_AND_EXPR. */ 577 578 case TRUTH_AND_EXPR: 579 /* High branch cost, expand as the bitwise AND of the conditions. 580 Do the same if the RHS has side effects, because we're effectively 581 turning a TRUTH_AND_EXPR into a TRUTH_ANDIF_EXPR. */ 582 if (BRANCH_COST (optimize_insn_for_speed_p (), 583 false) >= 4 584 || TREE_SIDE_EFFECTS (TREE_OPERAND (exp, 1))) 585 goto normal; 586 code = TRUTH_ANDIF_EXPR; 587 goto other_code; 588 589 case BIT_IOR_EXPR: 590 case TRUTH_OR_EXPR: 591 /* High branch cost, expand as the bitwise OR of the conditions. 592 Do the same if the RHS has side effects, because we're effectively 593 turning a TRUTH_OR_EXPR into a TRUTH_ORIF_EXPR. */ 594 if (BRANCH_COST (optimize_insn_for_speed_p (), false) >= 4 595 || TREE_SIDE_EFFECTS (TREE_OPERAND (exp, 1))) 596 goto normal; 597 code = TRUTH_ORIF_EXPR; 598 goto other_code; 599 600 /* Fall through and generate the normal code. */ 601 default: 602 normal: 603 temp = expand_normal (exp); 604 do_pending_stack_adjust (); 605 /* The RTL optimizers prefer comparisons against pseudos. */ 606 if (GET_CODE (temp) == SUBREG) 607 { 608 /* Compare promoted variables in their promoted mode. */ 609 if (SUBREG_PROMOTED_VAR_P (temp) 610 && REG_P (XEXP (temp, 0))) 611 temp = XEXP (temp, 0); 612 else 613 temp = copy_to_reg (temp); 614 } 615 do_compare_rtx_and_jump (temp, CONST0_RTX (GET_MODE (temp)), 616 NE, TYPE_UNSIGNED (TREE_TYPE (exp)), 617 GET_MODE (temp), NULL_RTX, 618 if_false_label, if_true_label, prob); 619 } 620 621 if (drop_through_label) 622 { 623 do_pending_stack_adjust (); 624 emit_label (drop_through_label); 625 } 626} 627 628/* Compare OP0 with OP1, word at a time, in mode MODE. 629 UNSIGNEDP says to do unsigned comparison. 630 Jump to IF_TRUE_LABEL if OP0 is greater, IF_FALSE_LABEL otherwise. */ 631 632static void 633do_jump_by_parts_greater_rtx (enum machine_mode mode, int unsignedp, rtx op0, 634 rtx op1, rtx if_false_label, rtx if_true_label, 635 int prob) 636{ 637 int nwords = (GET_MODE_SIZE (mode) / UNITS_PER_WORD); 638 rtx drop_through_label = 0; 639 int i; 640 641 if (! if_true_label || ! if_false_label) 642 drop_through_label = gen_label_rtx (); 643 if (! if_true_label) 644 if_true_label = drop_through_label; 645 if (! if_false_label) 646 if_false_label = drop_through_label; 647 648 /* Compare a word at a time, high order first. */ 649 for (i = 0; i < nwords; i++) 650 { 651 rtx op0_word, op1_word; 652 653 if (WORDS_BIG_ENDIAN) 654 { 655 op0_word = operand_subword_force (op0, i, mode); 656 op1_word = operand_subword_force (op1, i, mode); 657 } 658 else 659 { 660 op0_word = operand_subword_force (op0, nwords - 1 - i, mode); 661 op1_word = operand_subword_force (op1, nwords - 1 - i, mode); 662 } 663 664 /* All but high-order word must be compared as unsigned. */ 665 do_compare_rtx_and_jump (op0_word, op1_word, GT, 666 (unsignedp || i > 0), word_mode, NULL_RTX, 667 NULL_RTX, if_true_label, prob); 668 669 /* Consider lower words only if these are equal. */ 670 do_compare_rtx_and_jump (op0_word, op1_word, NE, unsignedp, word_mode, 671 NULL_RTX, NULL_RTX, if_false_label, 672 inv (prob)); 673 } 674 675 if (if_false_label) 676 emit_jump (if_false_label); 677 if (drop_through_label) 678 emit_label (drop_through_label); 679} 680 681/* Given a comparison expression EXP for values too wide to be compared 682 with one insn, test the comparison and jump to the appropriate label. 683 The code of EXP is ignored; we always test GT if SWAP is 0, 684 and LT if SWAP is 1. */ 685 686static void 687do_jump_by_parts_greater (tree treeop0, tree treeop1, int swap, 688 rtx if_false_label, rtx if_true_label, int prob) 689{ 690 rtx op0 = expand_normal (swap ? treeop1 : treeop0); 691 rtx op1 = expand_normal (swap ? treeop0 : treeop1); 692 enum machine_mode mode = TYPE_MODE (TREE_TYPE (treeop0)); 693 int unsignedp = TYPE_UNSIGNED (TREE_TYPE (treeop0)); 694 695 do_jump_by_parts_greater_rtx (mode, unsignedp, op0, op1, if_false_label, 696 if_true_label, prob); 697} 698 699/* Jump according to whether OP0 is 0. We assume that OP0 has an integer 700 mode, MODE, that is too wide for the available compare insns. Either 701 Either (but not both) of IF_TRUE_LABEL and IF_FALSE_LABEL may be NULL_RTX 702 to indicate drop through. */ 703 704static void 705do_jump_by_parts_zero_rtx (enum machine_mode mode, rtx op0, 706 rtx if_false_label, rtx if_true_label, int prob) 707{ 708 int nwords = GET_MODE_SIZE (mode) / UNITS_PER_WORD; 709 rtx part; 710 int i; 711 rtx drop_through_label = 0; 712 713 /* The fastest way of doing this comparison on almost any machine is to 714 "or" all the words and compare the result. If all have to be loaded 715 from memory and this is a very wide item, it's possible this may 716 be slower, but that's highly unlikely. */ 717 718 part = gen_reg_rtx (word_mode); 719 emit_move_insn (part, operand_subword_force (op0, 0, mode)); 720 for (i = 1; i < nwords && part != 0; i++) 721 part = expand_binop (word_mode, ior_optab, part, 722 operand_subword_force (op0, i, mode), 723 part, 1, OPTAB_WIDEN); 724 725 if (part != 0) 726 { 727 do_compare_rtx_and_jump (part, const0_rtx, EQ, 1, word_mode, 728 NULL_RTX, if_false_label, if_true_label, prob); 729 return; 730 } 731 732 /* If we couldn't do the "or" simply, do this with a series of compares. */ 733 if (! if_false_label) 734 drop_through_label = if_false_label = gen_label_rtx (); 735 736 for (i = 0; i < nwords; i++) 737 do_compare_rtx_and_jump (operand_subword_force (op0, i, mode), 738 const0_rtx, EQ, 1, word_mode, NULL_RTX, 739 if_false_label, NULL_RTX, prob); 740 741 if (if_true_label) 742 emit_jump (if_true_label); 743 744 if (drop_through_label) 745 emit_label (drop_through_label); 746} 747 748/* Test for the equality of two RTX expressions OP0 and OP1 in mode MODE, 749 where MODE is an integer mode too wide to be compared with one insn. 750 Either (but not both) of IF_TRUE_LABEL and IF_FALSE_LABEL may be NULL_RTX 751 to indicate drop through. */ 752 753static void 754do_jump_by_parts_equality_rtx (enum machine_mode mode, rtx op0, rtx op1, 755 rtx if_false_label, rtx if_true_label, int prob) 756{ 757 int nwords = (GET_MODE_SIZE (mode) / UNITS_PER_WORD); 758 rtx drop_through_label = 0; 759 int i; 760 761 if (op1 == const0_rtx) 762 { 763 do_jump_by_parts_zero_rtx (mode, op0, if_false_label, if_true_label, 764 prob); 765 return; 766 } 767 else if (op0 == const0_rtx) 768 { 769 do_jump_by_parts_zero_rtx (mode, op1, if_false_label, if_true_label, 770 prob); 771 return; 772 } 773 774 if (! if_false_label) 775 drop_through_label = if_false_label = gen_label_rtx (); 776 777 for (i = 0; i < nwords; i++) 778 do_compare_rtx_and_jump (operand_subword_force (op0, i, mode), 779 operand_subword_force (op1, i, mode), 780 EQ, 0, word_mode, NULL_RTX, 781 if_false_label, NULL_RTX, prob); 782 783 if (if_true_label) 784 emit_jump (if_true_label); 785 if (drop_through_label) 786 emit_label (drop_through_label); 787} 788 789/* Given an EQ_EXPR expression EXP for values too wide to be compared 790 with one insn, test the comparison and jump to the appropriate label. */ 791 792static void 793do_jump_by_parts_equality (tree treeop0, tree treeop1, rtx if_false_label, 794 rtx if_true_label, int prob) 795{ 796 rtx op0 = expand_normal (treeop0); 797 rtx op1 = expand_normal (treeop1); 798 enum machine_mode mode = TYPE_MODE (TREE_TYPE (treeop0)); 799 do_jump_by_parts_equality_rtx (mode, op0, op1, if_false_label, 800 if_true_label, prob); 801} 802 803/* Split a comparison into two others, the second of which has the other 804 "orderedness". The first is always ORDERED or UNORDERED if MODE 805 does not honor NaNs (which means that it can be skipped in that case; 806 see do_compare_rtx_and_jump). 807 808 The two conditions are written in *CODE1 and *CODE2. Return true if 809 the conditions must be ANDed, false if they must be ORed. */ 810 811bool 812split_comparison (enum rtx_code code, enum machine_mode mode, 813 enum rtx_code *code1, enum rtx_code *code2) 814{ 815 switch (code) 816 { 817 case LT: 818 *code1 = ORDERED; 819 *code2 = UNLT; 820 return true; 821 case LE: 822 *code1 = ORDERED; 823 *code2 = UNLE; 824 return true; 825 case GT: 826 *code1 = ORDERED; 827 *code2 = UNGT; 828 return true; 829 case GE: 830 *code1 = ORDERED; 831 *code2 = UNGE; 832 return true; 833 case EQ: 834 *code1 = ORDERED; 835 *code2 = UNEQ; 836 return true; 837 case NE: 838 *code1 = UNORDERED; 839 *code2 = LTGT; 840 return false; 841 case UNLT: 842 *code1 = UNORDERED; 843 *code2 = LT; 844 return false; 845 case UNLE: 846 *code1 = UNORDERED; 847 *code2 = LE; 848 return false; 849 case UNGT: 850 *code1 = UNORDERED; 851 *code2 = GT; 852 return false; 853 case UNGE: 854 *code1 = UNORDERED; 855 *code2 = GE; 856 return false; 857 case UNEQ: 858 *code1 = UNORDERED; 859 *code2 = EQ; 860 return false; 861 case LTGT: 862 /* Do not turn a trapping comparison into a non-trapping one. */ 863 if (HONOR_SNANS (mode)) 864 { 865 *code1 = LT; 866 *code2 = GT; 867 return false; 868 } 869 else 870 { 871 *code1 = ORDERED; 872 *code2 = NE; 873 return true; 874 } 875 default: 876 gcc_unreachable (); 877 } 878} 879 880 881/* Like do_compare_and_jump but expects the values to compare as two rtx's. 882 The decision as to signed or unsigned comparison must be made by the caller. 883 884 If MODE is BLKmode, SIZE is an RTX giving the size of the objects being 885 compared. */ 886 887void 888do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp, 889 enum machine_mode mode, rtx size, rtx if_false_label, 890 rtx if_true_label, int prob) 891{ 892 rtx tem; 893 rtx dummy_label = NULL_RTX; 894 rtx last; 895 896 /* Reverse the comparison if that is safe and we want to jump if it is 897 false. Also convert to the reverse comparison if the target can 898 implement it. */ 899 if ((! if_true_label 900 || ! can_compare_p (code, mode, ccp_jump)) 901 && (! FLOAT_MODE_P (mode) 902 || code == ORDERED || code == UNORDERED 903 || (! HONOR_NANS (mode) && (code == LTGT || code == UNEQ)) 904 || (! HONOR_SNANS (mode) && (code == EQ || code == NE)))) 905 { 906 enum rtx_code rcode; 907 if (FLOAT_MODE_P (mode)) 908 rcode = reverse_condition_maybe_unordered (code); 909 else 910 rcode = reverse_condition (code); 911 912 /* Canonicalize to UNORDERED for the libcall. */ 913 if (can_compare_p (rcode, mode, ccp_jump) 914 || (code == ORDERED && ! can_compare_p (ORDERED, mode, ccp_jump))) 915 { 916 tem = if_true_label; 917 if_true_label = if_false_label; 918 if_false_label = tem; 919 code = rcode; 920 prob = inv (prob); 921 } 922 } 923 924 /* If one operand is constant, make it the second one. Only do this 925 if the other operand is not constant as well. */ 926 927 if (swap_commutative_operands_p (op0, op1)) 928 { 929 tem = op0; 930 op0 = op1; 931 op1 = tem; 932 code = swap_condition (code); 933 } 934 935 do_pending_stack_adjust (); 936 937 code = unsignedp ? unsigned_condition (code) : code; 938 if (0 != (tem = simplify_relational_operation (code, mode, VOIDmode, 939 op0, op1))) 940 { 941 if (CONSTANT_P (tem)) 942 { 943 rtx label = (tem == const0_rtx || tem == CONST0_RTX (mode)) 944 ? if_false_label : if_true_label; 945 if (label) 946 emit_jump (label); 947 return; 948 } 949 950 code = GET_CODE (tem); 951 mode = GET_MODE (tem); 952 op0 = XEXP (tem, 0); 953 op1 = XEXP (tem, 1); 954 unsignedp = (code == GTU || code == LTU || code == GEU || code == LEU); 955 } 956 957 if (! if_true_label) 958 dummy_label = if_true_label = gen_label_rtx (); 959 960 if (GET_MODE_CLASS (mode) == MODE_INT 961 && ! can_compare_p (code, mode, ccp_jump)) 962 { 963 switch (code) 964 { 965 case LTU: 966 do_jump_by_parts_greater_rtx (mode, 1, op1, op0, 967 if_false_label, if_true_label, prob); 968 break; 969 970 case LEU: 971 do_jump_by_parts_greater_rtx (mode, 1, op0, op1, 972 if_true_label, if_false_label, 973 inv (prob)); 974 break; 975 976 case GTU: 977 do_jump_by_parts_greater_rtx (mode, 1, op0, op1, 978 if_false_label, if_true_label, prob); 979 break; 980 981 case GEU: 982 do_jump_by_parts_greater_rtx (mode, 1, op1, op0, 983 if_true_label, if_false_label, 984 inv (prob)); 985 break; 986 987 case LT: 988 do_jump_by_parts_greater_rtx (mode, 0, op1, op0, 989 if_false_label, if_true_label, prob); 990 break; 991 992 case LE: 993 do_jump_by_parts_greater_rtx (mode, 0, op0, op1, 994 if_true_label, if_false_label, 995 inv (prob)); 996 break; 997 998 case GT: 999 do_jump_by_parts_greater_rtx (mode, 0, op0, op1, 1000 if_false_label, if_true_label, prob); 1001 break; 1002 1003 case GE: 1004 do_jump_by_parts_greater_rtx (mode, 0, op1, op0, 1005 if_true_label, if_false_label, 1006 inv (prob)); 1007 break; 1008 1009 case EQ: 1010 do_jump_by_parts_equality_rtx (mode, op0, op1, if_false_label, 1011 if_true_label, prob); 1012 break; 1013 1014 case NE: 1015 do_jump_by_parts_equality_rtx (mode, op0, op1, if_true_label, 1016 if_false_label, inv (prob)); 1017 break; 1018 1019 default: 1020 gcc_unreachable (); 1021 } 1022 } 1023 else 1024 { 1025 if (GET_MODE_CLASS (mode) == MODE_FLOAT 1026 && ! can_compare_p (code, mode, ccp_jump) 1027 && can_compare_p (swap_condition (code), mode, ccp_jump)) 1028 { 1029 rtx tmp; 1030 code = swap_condition (code); 1031 tmp = op0; 1032 op0 = op1; 1033 op1 = tmp; 1034 } 1035 1036 else if (GET_MODE_CLASS (mode) == MODE_FLOAT 1037 && ! can_compare_p (code, mode, ccp_jump) 1038 1039 /* Never split ORDERED and UNORDERED. These must be implemented. */ 1040 && (code != ORDERED && code != UNORDERED) 1041 1042 /* Split a floating-point comparison if we can jump on other 1043 conditions... */ 1044 && (have_insn_for (COMPARE, mode) 1045 1046 /* ... or if there is no libcall for it. */ 1047 || code_to_optab[code] == NULL)) 1048 { 1049 enum rtx_code first_code; 1050 bool and_them = split_comparison (code, mode, &first_code, &code); 1051 1052 /* If there are no NaNs, the first comparison should always fall 1053 through. */ 1054 if (!HONOR_NANS (mode)) 1055 gcc_assert (first_code == (and_them ? ORDERED : UNORDERED)); 1056 1057 else 1058 { 1059 if (and_them) 1060 { 1061 rtx dest_label; 1062 /* If we only jump if true, just bypass the second jump. */ 1063 if (! if_false_label) 1064 { 1065 if (! dummy_label) 1066 dummy_label = gen_label_rtx (); 1067 dest_label = dummy_label; 1068 } 1069 else 1070 dest_label = if_false_label; 1071 do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode, 1072 size, dest_label, NULL_RTX, prob); 1073 } 1074 else 1075 do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode, 1076 size, NULL_RTX, if_true_label, prob); 1077 } 1078 } 1079 1080 last = get_last_insn (); 1081 emit_cmp_and_jump_insns (op0, op1, code, size, mode, unsignedp, 1082 if_true_label); 1083 if (prob != -1 && profile_status != PROFILE_ABSENT) 1084 { 1085 for (last = NEXT_INSN (last); 1086 last && NEXT_INSN (last); 1087 last = NEXT_INSN (last)) 1088 if (JUMP_P (last)) 1089 break; 1090 if (!last 1091 || !JUMP_P (last) 1092 || NEXT_INSN (last) 1093 || !any_condjump_p (last)) 1094 { 1095 if (dump_file) 1096 fprintf (dump_file, "Failed to add probability note\n"); 1097 } 1098 else 1099 { 1100 gcc_assert (!find_reg_note (last, REG_BR_PROB, 0)); 1101 add_reg_note (last, REG_BR_PROB, GEN_INT (prob)); 1102 } 1103 } 1104 } 1105 1106 if (if_false_label) 1107 emit_jump (if_false_label); 1108 if (dummy_label) 1109 emit_label (dummy_label); 1110} 1111 1112/* Generate code for a comparison expression EXP (including code to compute 1113 the values to be compared) and a conditional jump to IF_FALSE_LABEL and/or 1114 IF_TRUE_LABEL. One of the labels can be NULL_RTX, in which case the 1115 generated code will drop through. 1116 SIGNED_CODE should be the rtx operation for this comparison for 1117 signed data; UNSIGNED_CODE, likewise for use if data is unsigned. 1118 1119 We force a stack adjustment unless there are currently 1120 things pushed on the stack that aren't yet used. */ 1121 1122static void 1123do_compare_and_jump (tree treeop0, tree treeop1, enum rtx_code signed_code, 1124 enum rtx_code unsigned_code, rtx if_false_label, 1125 rtx if_true_label, int prob) 1126{ 1127 rtx op0, op1; 1128 tree type; 1129 enum machine_mode mode; 1130 int unsignedp; 1131 enum rtx_code code; 1132 1133 /* Don't crash if the comparison was erroneous. */ 1134 op0 = expand_normal (treeop0); 1135 if (TREE_CODE (treeop0) == ERROR_MARK) 1136 return; 1137 1138 op1 = expand_normal (treeop1); 1139 if (TREE_CODE (treeop1) == ERROR_MARK) 1140 return; 1141 1142 type = TREE_TYPE (treeop0); 1143 mode = TYPE_MODE (type); 1144 if (TREE_CODE (treeop0) == INTEGER_CST 1145 && (TREE_CODE (treeop1) != INTEGER_CST 1146 || (GET_MODE_BITSIZE (mode) 1147 > GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (treeop1)))))) 1148 { 1149 /* op0 might have been replaced by promoted constant, in which 1150 case the type of second argument should be used. */ 1151 type = TREE_TYPE (treeop1); 1152 mode = TYPE_MODE (type); 1153 } 1154 unsignedp = TYPE_UNSIGNED (type); 1155 code = unsignedp ? unsigned_code : signed_code; 1156 1157#ifdef HAVE_canonicalize_funcptr_for_compare 1158 /* If function pointers need to be "canonicalized" before they can 1159 be reliably compared, then canonicalize them. 1160 Only do this if *both* sides of the comparison are function pointers. 1161 If one side isn't, we want a noncanonicalized comparison. See PR 1162 middle-end/17564. */ 1163 if (HAVE_canonicalize_funcptr_for_compare 1164 && TREE_CODE (TREE_TYPE (treeop0)) == POINTER_TYPE 1165 && TREE_CODE (TREE_TYPE (TREE_TYPE (treeop0))) 1166 == FUNCTION_TYPE 1167 && TREE_CODE (TREE_TYPE (treeop1)) == POINTER_TYPE 1168 && TREE_CODE (TREE_TYPE (TREE_TYPE (treeop1))) 1169 == FUNCTION_TYPE) 1170 { 1171 rtx new_op0 = gen_reg_rtx (mode); 1172 rtx new_op1 = gen_reg_rtx (mode); 1173 1174 emit_insn (gen_canonicalize_funcptr_for_compare (new_op0, op0)); 1175 op0 = new_op0; 1176 1177 emit_insn (gen_canonicalize_funcptr_for_compare (new_op1, op1)); 1178 op1 = new_op1; 1179 } 1180#endif 1181 1182 do_compare_rtx_and_jump (op0, op1, code, unsignedp, mode, 1183 ((mode == BLKmode) 1184 ? expr_size (treeop0) : NULL_RTX), 1185 if_false_label, if_true_label, prob); 1186} 1187 1188#include "gt-dojump.h" 1189