1277675Sngie/* Perform instruction reorganizations for delay slot filling. 2277675Sngie Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 3277675Sngie 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. 4277675Sngie Contributed by Richard Kenner (kenner@vlsi1.ultra.nyu.edu). 5 Hacked by Michael Tiemann (tiemann@cygnus.com). 6 7This file is part of GCC. 8 9GCC is free software; you can redistribute it and/or modify it under 10the terms of the GNU General Public License as published by the Free 11Software Foundation; either version 2, or (at your option) any later 12version. 13 14GCC is distributed in the hope that it will be useful, but WITHOUT ANY 15WARRANTY; without even the implied warranty of MERCHANTABILITY or 16FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 17for more details. 18 19You should have received a copy of the GNU General Public License 20along with GCC; see the file COPYING. If not, write to the Free 21Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 2202110-1301, USA. */ 23 24/* Instruction reorganization pass. 25 26 This pass runs after register allocation and final jump 27 optimization. It should be the last pass to run before peephole. 28 It serves primarily to fill delay slots of insns, typically branch 29 and call insns. Other insns typically involve more complicated 30 interactions of data dependencies and resource constraints, and 31 are better handled by scheduling before register allocation (by the 32 function `schedule_insns'). 33 34 The Branch Penalty is the number of extra cycles that are needed to 35 execute a branch insn. On an ideal machine, branches take a single 36 cycle, and the Branch Penalty is 0. Several RISC machines approach 37 branch delays differently: 38 39 The MIPS has a single branch delay slot. Most insns 40 (except other branches) can be used to fill this slot. When the 41 slot is filled, two insns execute in two cycles, reducing the 42 branch penalty to zero. 43 44 The SPARC always has a branch delay slot, but its effects can be 45 annulled when the branch is not taken. This means that failing to 46 find other sources of insns, we can hoist an insn from the branch 47 target that would only be safe to execute knowing that the branch 48 is taken. 49 50 The HP-PA always has a branch delay slot. For unconditional branches 51 its effects can be annulled when the branch is taken. The effects 52 of the delay slot in a conditional branch can be nullified for forward 53 taken branches, or for untaken backward branches. This means 54 we can hoist insns from the fall-through path for forward branches or 55 steal insns from the target of backward branches. 56 57 The TMS320C3x and C4x have three branch delay slots. When the three 58 slots are filled, the branch penalty is zero. Most insns can fill the 59 delay slots except jump insns. 60 61 Three techniques for filling delay slots have been implemented so far: 62 63 (1) `fill_simple_delay_slots' is the simplest, most efficient way 64 to fill delay slots. This pass first looks for insns which come 65 from before the branch and which are safe to execute after the 66 branch. Then it searches after the insn requiring delay slots or, 67 in the case of a branch, for insns that are after the point at 68 which the branch merges into the fallthrough code, if such a point 69 exists. When such insns are found, the branch penalty decreases 70 and no code expansion takes place. 71 72 (2) `fill_eager_delay_slots' is more complicated: it is used for 73 scheduling conditional jumps, or for scheduling jumps which cannot 74 be filled using (1). A machine need not have annulled jumps to use 75 this strategy, but it helps (by keeping more options open). 76 `fill_eager_delay_slots' tries to guess the direction the branch 77 will go; if it guesses right 100% of the time, it can reduce the 78 branch penalty as much as `fill_simple_delay_slots' does. If it 79 guesses wrong 100% of the time, it might as well schedule nops. When 80 `fill_eager_delay_slots' takes insns from the fall-through path of 81 the jump, usually there is no code expansion; when it takes insns 82 from the branch target, there is code expansion if it is not the 83 only way to reach that target. 84 85 (3) `relax_delay_slots' uses a set of rules to simplify code that 86 has been reorganized by (1) and (2). It finds cases where 87 conditional test can be eliminated, jumps can be threaded, extra 88 insns can be eliminated, etc. It is the job of (1) and (2) to do a 89 good job of scheduling locally; `relax_delay_slots' takes care of 90 making the various individual schedules work well together. It is 91 especially tuned to handle the control flow interactions of branch 92 insns. It does nothing for insns with delay slots that do not 93 branch. 94 95 On machines that use CC0, we are very conservative. We will not make 96 a copy of an insn involving CC0 since we want to maintain a 1-1 97 correspondence between the insn that sets and uses CC0. The insns are 98 allowed to be separated by placing an insn that sets CC0 (but not an insn 99 that uses CC0; we could do this, but it doesn't seem worthwhile) in a 100 delay slot. In that case, we point each insn at the other with REG_CC_USER 101 and REG_CC_SETTER notes. Note that these restrictions affect very few 102 machines because most RISC machines with delay slots will not use CC0 103 (the RT is the only known exception at this point). 104 105 Not yet implemented: 106 107 The Acorn Risc Machine can conditionally execute most insns, so 108 it is profitable to move single insns into a position to execute 109 based on the condition code of the previous insn. 110 111 The HP-PA can conditionally nullify insns, providing a similar 112 effect to the ARM, differing mostly in which insn is "in charge". */ 113 114#include "config.h" 115#include "system.h" 116#include "coretypes.h" 117#include "tm.h" 118#include "toplev.h" 119#include "rtl.h" 120#include "tm_p.h" 121#include "expr.h" 122#include "function.h" 123#include "insn-config.h" 124#include "conditions.h" 125#include "hard-reg-set.h" 126#include "basic-block.h" 127#include "regs.h" 128#include "recog.h" 129#include "flags.h" 130#include "output.h" 131#include "obstack.h" 132#include "insn-attr.h" 133#include "resource.h" 134#include "except.h" 135#include "params.h" 136#include "timevar.h" 137#include "target.h" 138#include "tree-pass.h" 139 140#ifdef DELAY_SLOTS 141 142#ifndef ANNUL_IFTRUE_SLOTS 143#define eligible_for_annul_true(INSN, SLOTS, TRIAL, FLAGS) 0 144#endif 145#ifndef ANNUL_IFFALSE_SLOTS 146#define eligible_for_annul_false(INSN, SLOTS, TRIAL, FLAGS) 0 147#endif 148 149/* Insns which have delay slots that have not yet been filled. */ 150 151static struct obstack unfilled_slots_obstack; 152static rtx *unfilled_firstobj; 153 154/* Define macros to refer to the first and last slot containing unfilled 155 insns. These are used because the list may move and its address 156 should be recomputed at each use. */ 157 158#define unfilled_slots_base \ 159 ((rtx *) obstack_base (&unfilled_slots_obstack)) 160 161#define unfilled_slots_next \ 162 ((rtx *) obstack_next_free (&unfilled_slots_obstack)) 163 164/* Points to the label before the end of the function. */ 165static rtx end_of_function_label; 166 167/* Mapping between INSN_UID's and position in the code since INSN_UID's do 168 not always monotonically increase. */ 169static int *uid_to_ruid; 170 171/* Highest valid index in `uid_to_ruid'. */ 172static int max_uid; 173 174static int stop_search_p (rtx, int); 175static int resource_conflicts_p (struct resources *, struct resources *); 176static int insn_references_resource_p (rtx, struct resources *, int); 177static int insn_sets_resource_p (rtx, struct resources *, int); 178static rtx find_end_label (void); 179static rtx emit_delay_sequence (rtx, rtx, int); 180static rtx add_to_delay_list (rtx, rtx); 181static rtx delete_from_delay_slot (rtx); 182static void delete_scheduled_jump (rtx); 183static void note_delay_statistics (int, int); 184#if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS) 185static rtx optimize_skip (rtx); 186#endif 187static int get_jump_flags (rtx, rtx); 188static int rare_destination (rtx); 189static int mostly_true_jump (rtx, rtx); 190static rtx get_branch_condition (rtx, rtx); 191static int condition_dominates_p (rtx, rtx); 192static int redirect_with_delay_slots_safe_p (rtx, rtx, rtx); 193static int redirect_with_delay_list_safe_p (rtx, rtx, rtx); 194static int check_annul_list_true_false (int, rtx); 195static rtx steal_delay_list_from_target (rtx, rtx, rtx, rtx, 196 struct resources *, 197 struct resources *, 198 struct resources *, 199 int, int *, int *, rtx *); 200static rtx steal_delay_list_from_fallthrough (rtx, rtx, rtx, rtx, 201 struct resources *, 202 struct resources *, 203 struct resources *, 204 int, int *, int *); 205static void try_merge_delay_insns (rtx, rtx); 206static rtx redundant_insn (rtx, rtx, rtx); 207static int own_thread_p (rtx, rtx, int); 208static void update_block (rtx, rtx); 209static int reorg_redirect_jump (rtx, rtx); 210static void update_reg_dead_notes (rtx, rtx); 211static void fix_reg_dead_note (rtx, rtx); 212static void update_reg_unused_notes (rtx, rtx); 213static void fill_simple_delay_slots (int); 214static rtx fill_slots_from_thread (rtx, rtx, rtx, rtx, int, int, int, int, 215 int *, rtx); 216static void fill_eager_delay_slots (void); 217static void relax_delay_slots (rtx); 218#ifdef HAVE_return 219static void make_return_insns (rtx); 220#endif 221 222/* Return TRUE if this insn should stop the search for insn to fill delay 223 slots. LABELS_P indicates that labels should terminate the search. 224 In all cases, jumps terminate the search. */ 225 226static int 227stop_search_p (rtx insn, int labels_p) 228{ 229 if (insn == 0) 230 return 1; 231 232 /* If the insn can throw an exception that is caught within the function, 233 it may effectively perform a jump from the viewpoint of the function. 234 Therefore act like for a jump. */ 235 if (can_throw_internal (insn)) 236 return 1; 237 238 switch (GET_CODE (insn)) 239 { 240 case NOTE: 241 case CALL_INSN: 242 return 0; 243 244 case CODE_LABEL: 245 return labels_p; 246 247 case JUMP_INSN: 248 case BARRIER: 249 return 1; 250 251 case INSN: 252 /* OK unless it contains a delay slot or is an `asm' insn of some type. 253 We don't know anything about these. */ 254 return (GET_CODE (PATTERN (insn)) == SEQUENCE 255 || GET_CODE (PATTERN (insn)) == ASM_INPUT 256 || asm_noperands (PATTERN (insn)) >= 0); 257 258 default: 259 gcc_unreachable (); 260 } 261} 262 263/* Return TRUE if any resources are marked in both RES1 and RES2 or if either 264 resource set contains a volatile memory reference. Otherwise, return FALSE. */ 265 266static int 267resource_conflicts_p (struct resources *res1, struct resources *res2) 268{ 269 if ((res1->cc && res2->cc) || (res1->memory && res2->memory) 270 || (res1->unch_memory && res2->unch_memory) 271 || res1->volatil || res2->volatil) 272 return 1; 273 274#ifdef HARD_REG_SET 275 return (res1->regs & res2->regs) != HARD_CONST (0); 276#else 277 { 278 int i; 279 280 for (i = 0; i < HARD_REG_SET_LONGS; i++) 281 if ((res1->regs[i] & res2->regs[i]) != 0) 282 return 1; 283 return 0; 284 } 285#endif 286} 287 288/* Return TRUE if any resource marked in RES, a `struct resources', is 289 referenced by INSN. If INCLUDE_DELAYED_EFFECTS is set, return if the called 290 routine is using those resources. 291 292 We compute this by computing all the resources referenced by INSN and 293 seeing if this conflicts with RES. It might be faster to directly check 294 ourselves, and this is the way it used to work, but it means duplicating 295 a large block of complex code. */ 296 297static int 298insn_references_resource_p (rtx insn, struct resources *res, 299 int include_delayed_effects) 300{ 301 struct resources insn_res; 302 303 CLEAR_RESOURCE (&insn_res); 304 mark_referenced_resources (insn, &insn_res, include_delayed_effects); 305 return resource_conflicts_p (&insn_res, res); 306} 307 308/* Return TRUE if INSN modifies resources that are marked in RES. 309 INCLUDE_DELAYED_EFFECTS is set if the actions of that routine should be 310 included. CC0 is only modified if it is explicitly set; see comments 311 in front of mark_set_resources for details. */ 312 313static int 314insn_sets_resource_p (rtx insn, struct resources *res, 315 int include_delayed_effects) 316{ 317 struct resources insn_sets; 318 319 CLEAR_RESOURCE (&insn_sets); 320 mark_set_resources (insn, &insn_sets, 0, include_delayed_effects); 321 return resource_conflicts_p (&insn_sets, res); 322} 323 324/* Find a label at the end of the function or before a RETURN. If there 325 is none, try to make one. If that fails, returns 0. 326 327 The property of such a label is that it is placed just before the 328 epilogue or a bare RETURN insn, so that another bare RETURN can be 329 turned into a jump to the label unconditionally. In particular, the 330 label cannot be placed before a RETURN insn with a filled delay slot. 331 332 ??? There may be a problem with the current implementation. Suppose 333 we start with a bare RETURN insn and call find_end_label. It may set 334 end_of_function_label just before the RETURN. Suppose the machinery 335 is able to fill the delay slot of the RETURN insn afterwards. Then 336 end_of_function_label is no longer valid according to the property 337 described above and find_end_label will still return it unmodified. 338 Note that this is probably mitigated by the following observation: 339 once end_of_function_label is made, it is very likely the target of 340 a jump, so filling the delay slot of the RETURN will be much more 341 difficult. */ 342 343static rtx 344find_end_label (void) 345{ 346 rtx insn; 347 348 /* If we found one previously, return it. */ 349 if (end_of_function_label) 350 return end_of_function_label; 351 352 /* Otherwise, see if there is a label at the end of the function. If there 353 is, it must be that RETURN insns aren't needed, so that is our return 354 label and we don't have to do anything else. */ 355 356 insn = get_last_insn (); 357 while (NOTE_P (insn) 358 || (NONJUMP_INSN_P (insn) 359 && (GET_CODE (PATTERN (insn)) == USE 360 || GET_CODE (PATTERN (insn)) == CLOBBER))) 361 insn = PREV_INSN (insn); 362 363 /* When a target threads its epilogue we might already have a 364 suitable return insn. If so put a label before it for the 365 end_of_function_label. */ 366 if (BARRIER_P (insn) 367 && JUMP_P (PREV_INSN (insn)) 368 && GET_CODE (PATTERN (PREV_INSN (insn))) == RETURN) 369 { 370 rtx temp = PREV_INSN (PREV_INSN (insn)); 371 end_of_function_label = gen_label_rtx (); 372 LABEL_NUSES (end_of_function_label) = 0; 373 374 /* Put the label before an USE insns that may precede the RETURN insn. */ 375 while (GET_CODE (temp) == USE) 376 temp = PREV_INSN (temp); 377 378 emit_label_after (end_of_function_label, temp); 379 } 380 381 else if (LABEL_P (insn)) 382 end_of_function_label = insn; 383 else 384 { 385 end_of_function_label = gen_label_rtx (); 386 LABEL_NUSES (end_of_function_label) = 0; 387 /* If the basic block reorder pass moves the return insn to 388 some other place try to locate it again and put our 389 end_of_function_label there. */ 390 while (insn && ! (JUMP_P (insn) 391 && (GET_CODE (PATTERN (insn)) == RETURN))) 392 insn = PREV_INSN (insn); 393 if (insn) 394 { 395 insn = PREV_INSN (insn); 396 397 /* Put the label before an USE insns that may proceed the 398 RETURN insn. */ 399 while (GET_CODE (insn) == USE) 400 insn = PREV_INSN (insn); 401 402 emit_label_after (end_of_function_label, insn); 403 } 404 else 405 { 406#ifdef HAVE_epilogue 407 if (HAVE_epilogue 408#ifdef HAVE_return 409 && ! HAVE_return 410#endif 411 ) 412 { 413 /* The RETURN insn has its delay slot filled so we cannot 414 emit the label just before it. Since we already have 415 an epilogue and cannot emit a new RETURN, we cannot 416 emit the label at all. */ 417 end_of_function_label = NULL_RTX; 418 return end_of_function_label; 419 } 420#endif /* HAVE_epilogue */ 421 422 /* Otherwise, make a new label and emit a RETURN and BARRIER, 423 if needed. */ 424 emit_label (end_of_function_label); 425#ifdef HAVE_return 426 /* We don't bother trying to create a return insn if the 427 epilogue has filled delay-slots; we would have to try and 428 move the delay-slot fillers to the delay-slots for the new 429 return insn or in front of the new return insn. */ 430 if (current_function_epilogue_delay_list == NULL 431 && HAVE_return) 432 { 433 /* The return we make may have delay slots too. */ 434 rtx insn = gen_return (); 435 insn = emit_jump_insn (insn); 436 emit_barrier (); 437 if (num_delay_slots (insn) > 0) 438 obstack_ptr_grow (&unfilled_slots_obstack, insn); 439 } 440#endif 441 } 442 } 443 444 /* Show one additional use for this label so it won't go away until 445 we are done. */ 446 ++LABEL_NUSES (end_of_function_label); 447 448 return end_of_function_label; 449} 450 451/* Put INSN and LIST together in a SEQUENCE rtx of LENGTH, and replace 452 the pattern of INSN with the SEQUENCE. 453 454 Chain the insns so that NEXT_INSN of each insn in the sequence points to 455 the next and NEXT_INSN of the last insn in the sequence points to 456 the first insn after the sequence. Similarly for PREV_INSN. This makes 457 it easier to scan all insns. 458 459 Returns the SEQUENCE that replaces INSN. */ 460 461static rtx 462emit_delay_sequence (rtx insn, rtx list, int length) 463{ 464 int i = 1; 465 rtx li; 466 int had_barrier = 0; 467 468 /* Allocate the rtvec to hold the insns and the SEQUENCE. */ 469 rtvec seqv = rtvec_alloc (length + 1); 470 rtx seq = gen_rtx_SEQUENCE (VOIDmode, seqv); 471 rtx seq_insn = make_insn_raw (seq); 472 rtx first = get_insns (); 473 rtx last = get_last_insn (); 474 475 /* Make a copy of the insn having delay slots. */ 476 rtx delay_insn = copy_rtx (insn); 477 478 /* If INSN is followed by a BARRIER, delete the BARRIER since it will only 479 confuse further processing. Update LAST in case it was the last insn. 480 We will put the BARRIER back in later. */ 481 if (NEXT_INSN (insn) && BARRIER_P (NEXT_INSN (insn))) 482 { 483 delete_related_insns (NEXT_INSN (insn)); 484 last = get_last_insn (); 485 had_barrier = 1; 486 } 487 488 /* Splice our SEQUENCE into the insn stream where INSN used to be. */ 489 NEXT_INSN (seq_insn) = NEXT_INSN (insn); 490 PREV_INSN (seq_insn) = PREV_INSN (insn); 491 492 if (insn != last) 493 PREV_INSN (NEXT_INSN (seq_insn)) = seq_insn; 494 495 if (insn != first) 496 NEXT_INSN (PREV_INSN (seq_insn)) = seq_insn; 497 498 /* Note the calls to set_new_first_and_last_insn must occur after 499 SEQ_INSN has been completely spliced into the insn stream. 500 501 Otherwise CUR_INSN_UID will get set to an incorrect value because 502 set_new_first_and_last_insn will not find SEQ_INSN in the chain. */ 503 if (insn == last) 504 set_new_first_and_last_insn (first, seq_insn); 505 506 if (insn == first) 507 set_new_first_and_last_insn (seq_insn, last); 508 509 /* Build our SEQUENCE and rebuild the insn chain. */ 510 XVECEXP (seq, 0, 0) = delay_insn; 511 INSN_DELETED_P (delay_insn) = 0; 512 PREV_INSN (delay_insn) = PREV_INSN (seq_insn); 513 514 for (li = list; li; li = XEXP (li, 1), i++) 515 { 516 rtx tem = XEXP (li, 0); 517 rtx note, next; 518 519 /* Show that this copy of the insn isn't deleted. */ 520 INSN_DELETED_P (tem) = 0; 521 522 XVECEXP (seq, 0, i) = tem; 523 PREV_INSN (tem) = XVECEXP (seq, 0, i - 1); 524 NEXT_INSN (XVECEXP (seq, 0, i - 1)) = tem; 525 526 /* SPARC assembler, for instance, emit warning when debug info is output 527 into the delay slot. */ 528 if (INSN_LOCATOR (tem) && !INSN_LOCATOR (seq_insn)) 529 INSN_LOCATOR (seq_insn) = INSN_LOCATOR (tem); 530 INSN_LOCATOR (tem) = 0; 531 532 for (note = REG_NOTES (tem); note; note = next) 533 { 534 next = XEXP (note, 1); 535 switch (REG_NOTE_KIND (note)) 536 { 537 case REG_DEAD: 538 /* Remove any REG_DEAD notes because we can't rely on them now 539 that the insn has been moved. */ 540 remove_note (tem, note); 541 break; 542 543 case REG_LABEL: 544 /* Keep the label reference count up to date. */ 545 if (LABEL_P (XEXP (note, 0))) 546 LABEL_NUSES (XEXP (note, 0)) ++; 547 break; 548 549 default: 550 break; 551 } 552 } 553 } 554 555 NEXT_INSN (XVECEXP (seq, 0, length)) = NEXT_INSN (seq_insn); 556 557 /* If the previous insn is a SEQUENCE, update the NEXT_INSN pointer on the 558 last insn in that SEQUENCE to point to us. Similarly for the first 559 insn in the following insn if it is a SEQUENCE. */ 560 561 if (PREV_INSN (seq_insn) && NONJUMP_INSN_P (PREV_INSN (seq_insn)) 562 && GET_CODE (PATTERN (PREV_INSN (seq_insn))) == SEQUENCE) 563 NEXT_INSN (XVECEXP (PATTERN (PREV_INSN (seq_insn)), 0, 564 XVECLEN (PATTERN (PREV_INSN (seq_insn)), 0) - 1)) 565 = seq_insn; 566 567 if (NEXT_INSN (seq_insn) && NONJUMP_INSN_P (NEXT_INSN (seq_insn)) 568 && GET_CODE (PATTERN (NEXT_INSN (seq_insn))) == SEQUENCE) 569 PREV_INSN (XVECEXP (PATTERN (NEXT_INSN (seq_insn)), 0, 0)) = seq_insn; 570 571 /* If there used to be a BARRIER, put it back. */ 572 if (had_barrier) 573 emit_barrier_after (seq_insn); 574 575 gcc_assert (i == length + 1); 576 577 return seq_insn; 578} 579 580/* Add INSN to DELAY_LIST and return the head of the new list. The list must 581 be in the order in which the insns are to be executed. */ 582 583static rtx 584add_to_delay_list (rtx insn, rtx delay_list) 585{ 586 /* If we have an empty list, just make a new list element. If 587 INSN has its block number recorded, clear it since we may 588 be moving the insn to a new block. */ 589 590 if (delay_list == 0) 591 { 592 clear_hashed_info_for_insn (insn); 593 return gen_rtx_INSN_LIST (VOIDmode, insn, NULL_RTX); 594 } 595 596 /* Otherwise this must be an INSN_LIST. Add INSN to the end of the 597 list. */ 598 XEXP (delay_list, 1) = add_to_delay_list (insn, XEXP (delay_list, 1)); 599 600 return delay_list; 601} 602 603/* Delete INSN from the delay slot of the insn that it is in, which may 604 produce an insn with no delay slots. Return the new insn. */ 605 606static rtx 607delete_from_delay_slot (rtx insn) 608{ 609 rtx trial, seq_insn, seq, prev; 610 rtx delay_list = 0; 611 int i; 612 int had_barrier = 0; 613 614 /* We first must find the insn containing the SEQUENCE with INSN in its 615 delay slot. Do this by finding an insn, TRIAL, where 616 PREV_INSN (NEXT_INSN (TRIAL)) != TRIAL. */ 617 618 for (trial = insn; 619 PREV_INSN (NEXT_INSN (trial)) == trial; 620 trial = NEXT_INSN (trial)) 621 ; 622 623 seq_insn = PREV_INSN (NEXT_INSN (trial)); 624 seq = PATTERN (seq_insn); 625 626 if (NEXT_INSN (seq_insn) && BARRIER_P (NEXT_INSN (seq_insn))) 627 had_barrier = 1; 628 629 /* Create a delay list consisting of all the insns other than the one 630 we are deleting (unless we were the only one). */ 631 if (XVECLEN (seq, 0) > 2) 632 for (i = 1; i < XVECLEN (seq, 0); i++) 633 if (XVECEXP (seq, 0, i) != insn) 634 delay_list = add_to_delay_list (XVECEXP (seq, 0, i), delay_list); 635 636 /* Delete the old SEQUENCE, re-emit the insn that used to have the delay 637 list, and rebuild the delay list if non-empty. */ 638 prev = PREV_INSN (seq_insn); 639 trial = XVECEXP (seq, 0, 0); 640 delete_related_insns (seq_insn); 641 add_insn_after (trial, prev); 642 643 /* If there was a barrier after the old SEQUENCE, remit it. */ 644 if (had_barrier) 645 emit_barrier_after (trial); 646 647 /* If there are any delay insns, remit them. Otherwise clear the 648 annul flag. */ 649 if (delay_list) 650 trial = emit_delay_sequence (trial, delay_list, XVECLEN (seq, 0) - 2); 651 else if (INSN_P (trial)) 652 INSN_ANNULLED_BRANCH_P (trial) = 0; 653 654 INSN_FROM_TARGET_P (insn) = 0; 655 656 /* Show we need to fill this insn again. */ 657 obstack_ptr_grow (&unfilled_slots_obstack, trial); 658 659 return trial; 660} 661 662/* Delete INSN, a JUMP_INSN. If it is a conditional jump, we must track down 663 the insn that sets CC0 for it and delete it too. */ 664 665static void 666delete_scheduled_jump (rtx insn) 667{ 668 /* Delete the insn that sets cc0 for us. On machines without cc0, we could 669 delete the insn that sets the condition code, but it is hard to find it. 670 Since this case is rare anyway, don't bother trying; there would likely 671 be other insns that became dead anyway, which we wouldn't know to 672 delete. */ 673 674#ifdef HAVE_cc0 675 if (reg_mentioned_p (cc0_rtx, insn)) 676 { 677 rtx note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX); 678 679 /* If a reg-note was found, it points to an insn to set CC0. This 680 insn is in the delay list of some other insn. So delete it from 681 the delay list it was in. */ 682 if (note) 683 { 684 if (! FIND_REG_INC_NOTE (XEXP (note, 0), NULL_RTX) 685 && sets_cc0_p (PATTERN (XEXP (note, 0))) == 1) 686 delete_from_delay_slot (XEXP (note, 0)); 687 } 688 else 689 { 690 /* The insn setting CC0 is our previous insn, but it may be in 691 a delay slot. It will be the last insn in the delay slot, if 692 it is. */ 693 rtx trial = previous_insn (insn); 694 if (NOTE_P (trial)) 695 trial = prev_nonnote_insn (trial); 696 if (sets_cc0_p (PATTERN (trial)) != 1 697 || FIND_REG_INC_NOTE (trial, NULL_RTX)) 698 return; 699 if (PREV_INSN (NEXT_INSN (trial)) == trial) 700 delete_related_insns (trial); 701 else 702 delete_from_delay_slot (trial); 703 } 704 } 705#endif 706 707 delete_related_insns (insn); 708} 709 710/* Counters for delay-slot filling. */ 711 712#define NUM_REORG_FUNCTIONS 2 713#define MAX_DELAY_HISTOGRAM 3 714#define MAX_REORG_PASSES 2 715 716static int num_insns_needing_delays[NUM_REORG_FUNCTIONS][MAX_REORG_PASSES]; 717 718static int num_filled_delays[NUM_REORG_FUNCTIONS][MAX_DELAY_HISTOGRAM+1][MAX_REORG_PASSES]; 719 720static int reorg_pass_number; 721 722static void 723note_delay_statistics (int slots_filled, int index) 724{ 725 num_insns_needing_delays[index][reorg_pass_number]++; 726 if (slots_filled > MAX_DELAY_HISTOGRAM) 727 slots_filled = MAX_DELAY_HISTOGRAM; 728 num_filled_delays[index][slots_filled][reorg_pass_number]++; 729} 730 731#if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS) 732 733/* Optimize the following cases: 734 735 1. When a conditional branch skips over only one instruction, 736 use an annulling branch and put that insn in the delay slot. 737 Use either a branch that annuls when the condition if true or 738 invert the test with a branch that annuls when the condition is 739 false. This saves insns, since otherwise we must copy an insn 740 from the L1 target. 741 742 (orig) (skip) (otherwise) 743 Bcc.n L1 Bcc',a L1 Bcc,a L1' 744 insn insn insn2 745 L1: L1: L1: 746 insn2 insn2 insn2 747 insn3 insn3 L1': 748 insn3 749 750 2. When a conditional branch skips over only one instruction, 751 and after that, it unconditionally branches somewhere else, 752 perform the similar optimization. This saves executing the 753 second branch in the case where the inverted condition is true. 754 755 Bcc.n L1 Bcc',a L2 756 insn insn 757 L1: L1: 758 Bra L2 Bra L2 759 760 INSN is a JUMP_INSN. 761 762 This should be expanded to skip over N insns, where N is the number 763 of delay slots required. */ 764 765static rtx 766optimize_skip (rtx insn) 767{ 768 rtx trial = next_nonnote_insn (insn); 769 rtx next_trial = next_active_insn (trial); 770 rtx delay_list = 0; 771 int flags; 772 773 flags = get_jump_flags (insn, JUMP_LABEL (insn)); 774 775 if (trial == 0 776 || !NONJUMP_INSN_P (trial) 777 || GET_CODE (PATTERN (trial)) == SEQUENCE 778 || recog_memoized (trial) < 0 779 || (! eligible_for_annul_false (insn, 0, trial, flags) 780 && ! eligible_for_annul_true (insn, 0, trial, flags)) 781 || can_throw_internal (trial)) 782 return 0; 783 784 /* There are two cases where we are just executing one insn (we assume 785 here that a branch requires only one insn; this should be generalized 786 at some point): Where the branch goes around a single insn or where 787 we have one insn followed by a branch to the same label we branch to. 788 In both of these cases, inverting the jump and annulling the delay 789 slot give the same effect in fewer insns. */ 790 if ((next_trial == next_active_insn (JUMP_LABEL (insn)) 791 && ! (next_trial == 0 && current_function_epilogue_delay_list != 0)) 792 || (next_trial != 0 793 && JUMP_P (next_trial) 794 && JUMP_LABEL (insn) == JUMP_LABEL (next_trial) 795 && (simplejump_p (next_trial) 796 || GET_CODE (PATTERN (next_trial)) == RETURN))) 797 { 798 if (eligible_for_annul_false (insn, 0, trial, flags)) 799 { 800 if (invert_jump (insn, JUMP_LABEL (insn), 1)) 801 INSN_FROM_TARGET_P (trial) = 1; 802 else if (! eligible_for_annul_true (insn, 0, trial, flags)) 803 return 0; 804 } 805 806 delay_list = add_to_delay_list (trial, NULL_RTX); 807 next_trial = next_active_insn (trial); 808 update_block (trial, trial); 809 delete_related_insns (trial); 810 811 /* Also, if we are targeting an unconditional 812 branch, thread our jump to the target of that branch. Don't 813 change this into a RETURN here, because it may not accept what 814 we have in the delay slot. We'll fix this up later. */ 815 if (next_trial && JUMP_P (next_trial) 816 && (simplejump_p (next_trial) 817 || GET_CODE (PATTERN (next_trial)) == RETURN)) 818 { 819 rtx target_label = JUMP_LABEL (next_trial); 820 if (target_label == 0) 821 target_label = find_end_label (); 822 823 if (target_label) 824 { 825 /* Recompute the flags based on TARGET_LABEL since threading 826 the jump to TARGET_LABEL may change the direction of the 827 jump (which may change the circumstances in which the 828 delay slot is nullified). */ 829 flags = get_jump_flags (insn, target_label); 830 if (eligible_for_annul_true (insn, 0, trial, flags)) 831 reorg_redirect_jump (insn, target_label); 832 } 833 } 834 835 INSN_ANNULLED_BRANCH_P (insn) = 1; 836 } 837 838 return delay_list; 839} 840#endif 841 842/* Encode and return branch direction and prediction information for 843 INSN assuming it will jump to LABEL. 844 845 Non conditional branches return no direction information and 846 are predicted as very likely taken. */ 847 848static int 849get_jump_flags (rtx insn, rtx label) 850{ 851 int flags; 852 853 /* get_jump_flags can be passed any insn with delay slots, these may 854 be INSNs, CALL_INSNs, or JUMP_INSNs. Only JUMP_INSNs have branch 855 direction information, and only if they are conditional jumps. 856 857 If LABEL is zero, then there is no way to determine the branch 858 direction. */ 859 if (JUMP_P (insn) 860 && (condjump_p (insn) || condjump_in_parallel_p (insn)) 861 && INSN_UID (insn) <= max_uid 862 && label != 0 863 && INSN_UID (label) <= max_uid) 864 flags 865 = (uid_to_ruid[INSN_UID (label)] > uid_to_ruid[INSN_UID (insn)]) 866 ? ATTR_FLAG_forward : ATTR_FLAG_backward; 867 /* No valid direction information. */ 868 else 869 flags = 0; 870 871 /* If insn is a conditional branch call mostly_true_jump to get 872 determine the branch prediction. 873 874 Non conditional branches are predicted as very likely taken. */ 875 if (JUMP_P (insn) 876 && (condjump_p (insn) || condjump_in_parallel_p (insn))) 877 { 878 int prediction; 879 880 prediction = mostly_true_jump (insn, get_branch_condition (insn, label)); 881 switch (prediction) 882 { 883 case 2: 884 flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely); 885 break; 886 case 1: 887 flags |= ATTR_FLAG_likely; 888 break; 889 case 0: 890 flags |= ATTR_FLAG_unlikely; 891 break; 892 case -1: 893 flags |= (ATTR_FLAG_very_unlikely | ATTR_FLAG_unlikely); 894 break; 895 896 default: 897 gcc_unreachable (); 898 } 899 } 900 else 901 flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely); 902 903 return flags; 904} 905 906/* Return 1 if INSN is a destination that will be branched to rarely (the 907 return point of a function); return 2 if DEST will be branched to very 908 rarely (a call to a function that doesn't return). Otherwise, 909 return 0. */ 910 911static int 912rare_destination (rtx insn) 913{ 914 int jump_count = 0; 915 rtx next; 916 917 for (; insn; insn = next) 918 { 919 if (NONJUMP_INSN_P (insn) && GET_CODE (PATTERN (insn)) == SEQUENCE) 920 insn = XVECEXP (PATTERN (insn), 0, 0); 921 922 next = NEXT_INSN (insn); 923 924 switch (GET_CODE (insn)) 925 { 926 case CODE_LABEL: 927 return 0; 928 case BARRIER: 929 /* A BARRIER can either be after a JUMP_INSN or a CALL_INSN. We 930 don't scan past JUMP_INSNs, so any barrier we find here must 931 have been after a CALL_INSN and hence mean the call doesn't 932 return. */ 933 return 2; 934 case JUMP_INSN: 935 if (GET_CODE (PATTERN (insn)) == RETURN) 936 return 1; 937 else if (simplejump_p (insn) 938 && jump_count++ < 10) 939 next = JUMP_LABEL (insn); 940 else 941 return 0; 942 943 default: 944 break; 945 } 946 } 947 948 /* If we got here it means we hit the end of the function. So this 949 is an unlikely destination. */ 950 951 return 1; 952} 953 954/* Return truth value of the statement that this branch 955 is mostly taken. If we think that the branch is extremely likely 956 to be taken, we return 2. If the branch is slightly more likely to be 957 taken, return 1. If the branch is slightly less likely to be taken, 958 return 0 and if the branch is highly unlikely to be taken, return -1. 959 960 CONDITION, if nonzero, is the condition that JUMP_INSN is testing. */ 961 962static int 963mostly_true_jump (rtx jump_insn, rtx condition) 964{ 965 rtx target_label = JUMP_LABEL (jump_insn); 966 rtx note; 967 int rare_dest, rare_fallthrough; 968 969 /* If branch probabilities are available, then use that number since it 970 always gives a correct answer. */ 971 note = find_reg_note (jump_insn, REG_BR_PROB, 0); 972 if (note) 973 { 974 int prob = INTVAL (XEXP (note, 0)); 975 976 if (prob >= REG_BR_PROB_BASE * 9 / 10) 977 return 2; 978 else if (prob >= REG_BR_PROB_BASE / 2) 979 return 1; 980 else if (prob >= REG_BR_PROB_BASE / 10) 981 return 0; 982 else 983 return -1; 984 } 985 986 /* Look at the relative rarities of the fallthrough and destination. If 987 they differ, we can predict the branch that way. */ 988 rare_dest = rare_destination (target_label); 989 rare_fallthrough = rare_destination (NEXT_INSN (jump_insn)); 990 991 switch (rare_fallthrough - rare_dest) 992 { 993 case -2: 994 return -1; 995 case -1: 996 return 0; 997 case 0: 998 break; 999 case 1: 1000 return 1; 1001 case 2: 1002 return 2; 1003 } 1004 1005 /* If we couldn't figure out what this jump was, assume it won't be 1006 taken. This should be rare. */ 1007 if (condition == 0) 1008 return 0; 1009 1010 /* Predict backward branches usually take, forward branches usually not. If 1011 we don't know whether this is forward or backward, assume the branch 1012 will be taken, since most are. */ 1013 return (target_label == 0 || INSN_UID (jump_insn) > max_uid 1014 || INSN_UID (target_label) > max_uid 1015 || (uid_to_ruid[INSN_UID (jump_insn)] 1016 > uid_to_ruid[INSN_UID (target_label)])); 1017} 1018 1019/* Return the condition under which INSN will branch to TARGET. If TARGET 1020 is zero, return the condition under which INSN will return. If INSN is 1021 an unconditional branch, return const_true_rtx. If INSN isn't a simple 1022 type of jump, or it doesn't go to TARGET, return 0. */ 1023 1024static rtx 1025get_branch_condition (rtx insn, rtx target) 1026{ 1027 rtx pat = PATTERN (insn); 1028 rtx src; 1029 1030 if (condjump_in_parallel_p (insn)) 1031 pat = XVECEXP (pat, 0, 0); 1032 1033 if (GET_CODE (pat) == RETURN) 1034 return target == 0 ? const_true_rtx : 0; 1035 1036 else if (GET_CODE (pat) != SET || SET_DEST (pat) != pc_rtx) 1037 return 0; 1038 1039 src = SET_SRC (pat); 1040 if (GET_CODE (src) == LABEL_REF && XEXP (src, 0) == target) 1041 return const_true_rtx; 1042 1043 else if (GET_CODE (src) == IF_THEN_ELSE 1044 && ((target == 0 && GET_CODE (XEXP (src, 1)) == RETURN) 1045 || (GET_CODE (XEXP (src, 1)) == LABEL_REF 1046 && XEXP (XEXP (src, 1), 0) == target)) 1047 && XEXP (src, 2) == pc_rtx) 1048 return XEXP (src, 0); 1049 1050 else if (GET_CODE (src) == IF_THEN_ELSE 1051 && ((target == 0 && GET_CODE (XEXP (src, 2)) == RETURN) 1052 || (GET_CODE (XEXP (src, 2)) == LABEL_REF 1053 && XEXP (XEXP (src, 2), 0) == target)) 1054 && XEXP (src, 1) == pc_rtx) 1055 { 1056 enum rtx_code rev; 1057 rev = reversed_comparison_code (XEXP (src, 0), insn); 1058 if (rev != UNKNOWN) 1059 return gen_rtx_fmt_ee (rev, GET_MODE (XEXP (src, 0)), 1060 XEXP (XEXP (src, 0), 0), 1061 XEXP (XEXP (src, 0), 1)); 1062 } 1063 1064 return 0; 1065} 1066 1067/* Return nonzero if CONDITION is more strict than the condition of 1068 INSN, i.e., if INSN will always branch if CONDITION is true. */ 1069 1070static int 1071condition_dominates_p (rtx condition, rtx insn) 1072{ 1073 rtx other_condition = get_branch_condition (insn, JUMP_LABEL (insn)); 1074 enum rtx_code code = GET_CODE (condition); 1075 enum rtx_code other_code; 1076 1077 if (rtx_equal_p (condition, other_condition) 1078 || other_condition == const_true_rtx) 1079 return 1; 1080 1081 else if (condition == const_true_rtx || other_condition == 0) 1082 return 0; 1083 1084 other_code = GET_CODE (other_condition); 1085 if (GET_RTX_LENGTH (code) != 2 || GET_RTX_LENGTH (other_code) != 2 1086 || ! rtx_equal_p (XEXP (condition, 0), XEXP (other_condition, 0)) 1087 || ! rtx_equal_p (XEXP (condition, 1), XEXP (other_condition, 1))) 1088 return 0; 1089 1090 return comparison_dominates_p (code, other_code); 1091} 1092 1093/* Return nonzero if redirecting JUMP to NEWLABEL does not invalidate 1094 any insns already in the delay slot of JUMP. */ 1095 1096static int 1097redirect_with_delay_slots_safe_p (rtx jump, rtx newlabel, rtx seq) 1098{ 1099 int flags, i; 1100 rtx pat = PATTERN (seq); 1101 1102 /* Make sure all the delay slots of this jump would still 1103 be valid after threading the jump. If they are still 1104 valid, then return nonzero. */ 1105 1106 flags = get_jump_flags (jump, newlabel); 1107 for (i = 1; i < XVECLEN (pat, 0); i++) 1108 if (! ( 1109#ifdef ANNUL_IFFALSE_SLOTS 1110 (INSN_ANNULLED_BRANCH_P (jump) 1111 && INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) 1112 ? eligible_for_annul_false (jump, i - 1, 1113 XVECEXP (pat, 0, i), flags) : 1114#endif 1115#ifdef ANNUL_IFTRUE_SLOTS 1116 (INSN_ANNULLED_BRANCH_P (jump) 1117 && ! INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) 1118 ? eligible_for_annul_true (jump, i - 1, 1119 XVECEXP (pat, 0, i), flags) : 1120#endif 1121 eligible_for_delay (jump, i - 1, XVECEXP (pat, 0, i), flags))) 1122 break; 1123 1124 return (i == XVECLEN (pat, 0)); 1125} 1126 1127/* Return nonzero if redirecting JUMP to NEWLABEL does not invalidate 1128 any insns we wish to place in the delay slot of JUMP. */ 1129 1130static int 1131redirect_with_delay_list_safe_p (rtx jump, rtx newlabel, rtx delay_list) 1132{ 1133 int flags, i; 1134 rtx li; 1135 1136 /* Make sure all the insns in DELAY_LIST would still be 1137 valid after threading the jump. If they are still 1138 valid, then return nonzero. */ 1139 1140 flags = get_jump_flags (jump, newlabel); 1141 for (li = delay_list, i = 0; li; li = XEXP (li, 1), i++) 1142 if (! ( 1143#ifdef ANNUL_IFFALSE_SLOTS 1144 (INSN_ANNULLED_BRANCH_P (jump) 1145 && INSN_FROM_TARGET_P (XEXP (li, 0))) 1146 ? eligible_for_annul_false (jump, i, XEXP (li, 0), flags) : 1147#endif 1148#ifdef ANNUL_IFTRUE_SLOTS 1149 (INSN_ANNULLED_BRANCH_P (jump) 1150 && ! INSN_FROM_TARGET_P (XEXP (li, 0))) 1151 ? eligible_for_annul_true (jump, i, XEXP (li, 0), flags) : 1152#endif 1153 eligible_for_delay (jump, i, XEXP (li, 0), flags))) 1154 break; 1155 1156 return (li == NULL); 1157} 1158 1159/* DELAY_LIST is a list of insns that have already been placed into delay 1160 slots. See if all of them have the same annulling status as ANNUL_TRUE_P. 1161 If not, return 0; otherwise return 1. */ 1162 1163static int 1164check_annul_list_true_false (int annul_true_p, rtx delay_list) 1165{ 1166 rtx temp; 1167 1168 if (delay_list) 1169 { 1170 for (temp = delay_list; temp; temp = XEXP (temp, 1)) 1171 { 1172 rtx trial = XEXP (temp, 0); 1173 1174 if ((annul_true_p && INSN_FROM_TARGET_P (trial)) 1175 || (!annul_true_p && !INSN_FROM_TARGET_P (trial))) 1176 return 0; 1177 } 1178 } 1179 1180 return 1; 1181} 1182 1183/* INSN branches to an insn whose pattern SEQ is a SEQUENCE. Given that 1184 the condition tested by INSN is CONDITION and the resources shown in 1185 OTHER_NEEDED are needed after INSN, see whether INSN can take all the insns 1186 from SEQ's delay list, in addition to whatever insns it may execute 1187 (in DELAY_LIST). SETS and NEEDED are denote resources already set and 1188 needed while searching for delay slot insns. Return the concatenated 1189 delay list if possible, otherwise, return 0. 1190 1191 SLOTS_TO_FILL is the total number of slots required by INSN, and 1192 PSLOTS_FILLED points to the number filled so far (also the number of 1193 insns in DELAY_LIST). It is updated with the number that have been 1194 filled from the SEQUENCE, if any. 1195 1196 PANNUL_P points to a nonzero value if we already know that we need 1197 to annul INSN. If this routine determines that annulling is needed, 1198 it may set that value nonzero. 1199 1200 PNEW_THREAD points to a location that is to receive the place at which 1201 execution should continue. */ 1202 1203static rtx 1204steal_delay_list_from_target (rtx insn, rtx condition, rtx seq, 1205 rtx delay_list, struct resources *sets, 1206 struct resources *needed, 1207 struct resources *other_needed, 1208 int slots_to_fill, int *pslots_filled, 1209 int *pannul_p, rtx *pnew_thread) 1210{ 1211 rtx temp; 1212 int slots_remaining = slots_to_fill - *pslots_filled; 1213 int total_slots_filled = *pslots_filled; 1214 rtx new_delay_list = 0; 1215 int must_annul = *pannul_p; 1216 int used_annul = 0; 1217 int i; 1218 struct resources cc_set; 1219 1220 /* We can't do anything if there are more delay slots in SEQ than we 1221 can handle, or if we don't know that it will be a taken branch. 1222 We know that it will be a taken branch if it is either an unconditional 1223 branch or a conditional branch with a stricter branch condition. 1224 1225 Also, exit if the branch has more than one set, since then it is computing 1226 other results that can't be ignored, e.g. the HPPA mov&branch instruction. 1227 ??? It may be possible to move other sets into INSN in addition to 1228 moving the instructions in the delay slots. 1229 1230 We can not steal the delay list if one of the instructions in the 1231 current delay_list modifies the condition codes and the jump in the 1232 sequence is a conditional jump. We can not do this because we can 1233 not change the direction of the jump because the condition codes 1234 will effect the direction of the jump in the sequence. */ 1235 1236 CLEAR_RESOURCE (&cc_set); 1237 for (temp = delay_list; temp; temp = XEXP (temp, 1)) 1238 { 1239 rtx trial = XEXP (temp, 0); 1240 1241 mark_set_resources (trial, &cc_set, 0, MARK_SRC_DEST_CALL); 1242 if (insn_references_resource_p (XVECEXP (seq , 0, 0), &cc_set, 0)) 1243 return delay_list; 1244 } 1245 1246 if (XVECLEN (seq, 0) - 1 > slots_remaining 1247 || ! condition_dominates_p (condition, XVECEXP (seq, 0, 0)) 1248 || ! single_set (XVECEXP (seq, 0, 0))) 1249 return delay_list; 1250 1251#ifdef MD_CAN_REDIRECT_BRANCH 1252 /* On some targets, branches with delay slots can have a limited 1253 displacement. Give the back end a chance to tell us we can't do 1254 this. */ 1255 if (! MD_CAN_REDIRECT_BRANCH (insn, XVECEXP (seq, 0, 0))) 1256 return delay_list; 1257#endif 1258 1259 for (i = 1; i < XVECLEN (seq, 0); i++) 1260 { 1261 rtx trial = XVECEXP (seq, 0, i); 1262 int flags; 1263 1264 if (insn_references_resource_p (trial, sets, 0) 1265 || insn_sets_resource_p (trial, needed, 0) 1266 || insn_sets_resource_p (trial, sets, 0) 1267#ifdef HAVE_cc0 1268 /* If TRIAL sets CC0, we can't copy it, so we can't steal this 1269 delay list. */ 1270 || find_reg_note (trial, REG_CC_USER, NULL_RTX) 1271#endif 1272 /* If TRIAL is from the fallthrough code of an annulled branch insn 1273 in SEQ, we cannot use it. */ 1274 || (INSN_ANNULLED_BRANCH_P (XVECEXP (seq, 0, 0)) 1275 && ! INSN_FROM_TARGET_P (trial))) 1276 return delay_list; 1277 1278 /* If this insn was already done (usually in a previous delay slot), 1279 pretend we put it in our delay slot. */ 1280 if (redundant_insn (trial, insn, new_delay_list)) 1281 continue; 1282 1283 /* We will end up re-vectoring this branch, so compute flags 1284 based on jumping to the new label. */ 1285 flags = get_jump_flags (insn, JUMP_LABEL (XVECEXP (seq, 0, 0))); 1286 1287 if (! must_annul 1288 && ((condition == const_true_rtx 1289 || (! insn_sets_resource_p (trial, other_needed, 0) 1290 && ! may_trap_or_fault_p (PATTERN (trial))))) 1291 ? eligible_for_delay (insn, total_slots_filled, trial, flags) 1292 : (must_annul || (delay_list == NULL && new_delay_list == NULL)) 1293 && (must_annul = 1, 1294 check_annul_list_true_false (0, delay_list) 1295 && check_annul_list_true_false (0, new_delay_list) 1296 && eligible_for_annul_false (insn, total_slots_filled, 1297 trial, flags))) 1298 { 1299 if (must_annul) 1300 used_annul = 1; 1301 temp = copy_rtx (trial); 1302 INSN_FROM_TARGET_P (temp) = 1; 1303 new_delay_list = add_to_delay_list (temp, new_delay_list); 1304 total_slots_filled++; 1305 1306 if (--slots_remaining == 0) 1307 break; 1308 } 1309 else 1310 return delay_list; 1311 } 1312 1313 /* Show the place to which we will be branching. */ 1314 *pnew_thread = next_active_insn (JUMP_LABEL (XVECEXP (seq, 0, 0))); 1315 1316 /* Add any new insns to the delay list and update the count of the 1317 number of slots filled. */ 1318 *pslots_filled = total_slots_filled; 1319 if (used_annul) 1320 *pannul_p = 1; 1321 1322 if (delay_list == 0) 1323 return new_delay_list; 1324 1325 for (temp = new_delay_list; temp; temp = XEXP (temp, 1)) 1326 delay_list = add_to_delay_list (XEXP (temp, 0), delay_list); 1327 1328 return delay_list; 1329} 1330 1331/* Similar to steal_delay_list_from_target except that SEQ is on the 1332 fallthrough path of INSN. Here we only do something if the delay insn 1333 of SEQ is an unconditional branch. In that case we steal its delay slot 1334 for INSN since unconditional branches are much easier to fill. */ 1335 1336static rtx 1337steal_delay_list_from_fallthrough (rtx insn, rtx condition, rtx seq, 1338 rtx delay_list, struct resources *sets, 1339 struct resources *needed, 1340 struct resources *other_needed, 1341 int slots_to_fill, int *pslots_filled, 1342 int *pannul_p) 1343{ 1344 int i; 1345 int flags; 1346 int must_annul = *pannul_p; 1347 int used_annul = 0; 1348 1349 flags = get_jump_flags (insn, JUMP_LABEL (insn)); 1350 1351 /* We can't do anything if SEQ's delay insn isn't an 1352 unconditional branch. */ 1353 1354 if (! simplejump_p (XVECEXP (seq, 0, 0)) 1355 && GET_CODE (PATTERN (XVECEXP (seq, 0, 0))) != RETURN) 1356 return delay_list; 1357 1358 for (i = 1; i < XVECLEN (seq, 0); i++) 1359 { 1360 rtx trial = XVECEXP (seq, 0, i); 1361 1362 /* If TRIAL sets CC0, stealing it will move it too far from the use 1363 of CC0. */ 1364 if (insn_references_resource_p (trial, sets, 0) 1365 || insn_sets_resource_p (trial, needed, 0) 1366 || insn_sets_resource_p (trial, sets, 0) 1367#ifdef HAVE_cc0 1368 || sets_cc0_p (PATTERN (trial)) 1369#endif 1370 ) 1371 1372 break; 1373 1374 /* If this insn was already done, we don't need it. */ 1375 if (redundant_insn (trial, insn, delay_list)) 1376 { 1377 delete_from_delay_slot (trial); 1378 continue; 1379 } 1380 1381 if (! must_annul 1382 && ((condition == const_true_rtx 1383 || (! insn_sets_resource_p (trial, other_needed, 0) 1384 && ! may_trap_or_fault_p (PATTERN (trial))))) 1385 ? eligible_for_delay (insn, *pslots_filled, trial, flags) 1386 : (must_annul || delay_list == NULL) && (must_annul = 1, 1387 check_annul_list_true_false (1, delay_list) 1388 && eligible_for_annul_true (insn, *pslots_filled, trial, flags))) 1389 { 1390 if (must_annul) 1391 used_annul = 1; 1392 delete_from_delay_slot (trial); 1393 delay_list = add_to_delay_list (trial, delay_list); 1394 1395 if (++(*pslots_filled) == slots_to_fill) 1396 break; 1397 } 1398 else 1399 break; 1400 } 1401 1402 if (used_annul) 1403 *pannul_p = 1; 1404 return delay_list; 1405} 1406 1407/* Try merging insns starting at THREAD which match exactly the insns in 1408 INSN's delay list. 1409 1410 If all insns were matched and the insn was previously annulling, the 1411 annul bit will be cleared. 1412 1413 For each insn that is merged, if the branch is or will be non-annulling, 1414 we delete the merged insn. */ 1415 1416static void 1417try_merge_delay_insns (rtx insn, rtx thread) 1418{ 1419 rtx trial, next_trial; 1420 rtx delay_insn = XVECEXP (PATTERN (insn), 0, 0); 1421 int annul_p = INSN_ANNULLED_BRANCH_P (delay_insn); 1422 int slot_number = 1; 1423 int num_slots = XVECLEN (PATTERN (insn), 0); 1424 rtx next_to_match = XVECEXP (PATTERN (insn), 0, slot_number); 1425 struct resources set, needed; 1426 rtx merged_insns = 0; 1427 int i; 1428 int flags; 1429 1430 flags = get_jump_flags (delay_insn, JUMP_LABEL (delay_insn)); 1431 1432 CLEAR_RESOURCE (&needed); 1433 CLEAR_RESOURCE (&set); 1434 1435 /* If this is not an annulling branch, take into account anything needed in 1436 INSN's delay slot. This prevents two increments from being incorrectly 1437 folded into one. If we are annulling, this would be the correct 1438 thing to do. (The alternative, looking at things set in NEXT_TO_MATCH 1439 will essentially disable this optimization. This method is somewhat of 1440 a kludge, but I don't see a better way.) */ 1441 if (! annul_p) 1442 for (i = 1 ; i < num_slots; i++) 1443 if (XVECEXP (PATTERN (insn), 0, i)) 1444 mark_referenced_resources (XVECEXP (PATTERN (insn), 0, i), &needed, 1); 1445 1446 for (trial = thread; !stop_search_p (trial, 1); trial = next_trial) 1447 { 1448 rtx pat = PATTERN (trial); 1449 rtx oldtrial = trial; 1450 1451 next_trial = next_nonnote_insn (trial); 1452 1453 /* TRIAL must be a CALL_INSN or INSN. Skip USE and CLOBBER. */ 1454 if (NONJUMP_INSN_P (trial) 1455 && (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)) 1456 continue; 1457 1458 if (GET_CODE (next_to_match) == GET_CODE (trial) 1459#ifdef HAVE_cc0 1460 /* We can't share an insn that sets cc0. */ 1461 && ! sets_cc0_p (pat) 1462#endif 1463 && ! insn_references_resource_p (trial, &set, 1) 1464 && ! insn_sets_resource_p (trial, &set, 1) 1465 && ! insn_sets_resource_p (trial, &needed, 1) 1466 && (trial = try_split (pat, trial, 0)) != 0 1467 /* Update next_trial, in case try_split succeeded. */ 1468 && (next_trial = next_nonnote_insn (trial)) 1469 /* Likewise THREAD. */ 1470 && (thread = oldtrial == thread ? trial : thread) 1471 && rtx_equal_p (PATTERN (next_to_match), PATTERN (trial)) 1472 /* Have to test this condition if annul condition is different 1473 from (and less restrictive than) non-annulling one. */ 1474 && eligible_for_delay (delay_insn, slot_number - 1, trial, flags)) 1475 { 1476 1477 if (! annul_p) 1478 { 1479 update_block (trial, thread); 1480 if (trial == thread) 1481 thread = next_active_insn (thread); 1482 1483 delete_related_insns (trial); 1484 INSN_FROM_TARGET_P (next_to_match) = 0; 1485 } 1486 else 1487 merged_insns = gen_rtx_INSN_LIST (VOIDmode, trial, merged_insns); 1488 1489 if (++slot_number == num_slots) 1490 break; 1491 1492 next_to_match = XVECEXP (PATTERN (insn), 0, slot_number); 1493 } 1494 1495 mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL); 1496 mark_referenced_resources (trial, &needed, 1); 1497 } 1498 1499 /* See if we stopped on a filled insn. If we did, try to see if its 1500 delay slots match. */ 1501 if (slot_number != num_slots 1502 && trial && NONJUMP_INSN_P (trial) 1503 && GET_CODE (PATTERN (trial)) == SEQUENCE 1504 && ! INSN_ANNULLED_BRANCH_P (XVECEXP (PATTERN (trial), 0, 0))) 1505 { 1506 rtx pat = PATTERN (trial); 1507 rtx filled_insn = XVECEXP (pat, 0, 0); 1508 1509 /* Account for resources set/needed by the filled insn. */ 1510 mark_set_resources (filled_insn, &set, 0, MARK_SRC_DEST_CALL); 1511 mark_referenced_resources (filled_insn, &needed, 1); 1512 1513 for (i = 1; i < XVECLEN (pat, 0); i++) 1514 { 1515 rtx dtrial = XVECEXP (pat, 0, i); 1516 1517 if (! insn_references_resource_p (dtrial, &set, 1) 1518 && ! insn_sets_resource_p (dtrial, &set, 1) 1519 && ! insn_sets_resource_p (dtrial, &needed, 1) 1520#ifdef HAVE_cc0 1521 && ! sets_cc0_p (PATTERN (dtrial)) 1522#endif 1523 && rtx_equal_p (PATTERN (next_to_match), PATTERN (dtrial)) 1524 && eligible_for_delay (delay_insn, slot_number - 1, dtrial, flags)) 1525 { 1526 if (! annul_p) 1527 { 1528 rtx new; 1529 1530 update_block (dtrial, thread); 1531 new = delete_from_delay_slot (dtrial); 1532 if (INSN_DELETED_P (thread)) 1533 thread = new; 1534 INSN_FROM_TARGET_P (next_to_match) = 0; 1535 } 1536 else 1537 merged_insns = gen_rtx_INSN_LIST (SImode, dtrial, 1538 merged_insns); 1539 1540 if (++slot_number == num_slots) 1541 break; 1542 1543 next_to_match = XVECEXP (PATTERN (insn), 0, slot_number); 1544 } 1545 else 1546 { 1547 /* Keep track of the set/referenced resources for the delay 1548 slots of any trial insns we encounter. */ 1549 mark_set_resources (dtrial, &set, 0, MARK_SRC_DEST_CALL); 1550 mark_referenced_resources (dtrial, &needed, 1); 1551 } 1552 } 1553 } 1554 1555 /* If all insns in the delay slot have been matched and we were previously 1556 annulling the branch, we need not any more. In that case delete all the 1557 merged insns. Also clear the INSN_FROM_TARGET_P bit of each insn in 1558 the delay list so that we know that it isn't only being used at the 1559 target. */ 1560 if (slot_number == num_slots && annul_p) 1561 { 1562 for (; merged_insns; merged_insns = XEXP (merged_insns, 1)) 1563 { 1564 if (GET_MODE (merged_insns) == SImode) 1565 { 1566 rtx new; 1567 1568 update_block (XEXP (merged_insns, 0), thread); 1569 new = delete_from_delay_slot (XEXP (merged_insns, 0)); 1570 if (INSN_DELETED_P (thread)) 1571 thread = new; 1572 } 1573 else 1574 { 1575 update_block (XEXP (merged_insns, 0), thread); 1576 delete_related_insns (XEXP (merged_insns, 0)); 1577 } 1578 } 1579 1580 INSN_ANNULLED_BRANCH_P (delay_insn) = 0; 1581 1582 for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++) 1583 INSN_FROM_TARGET_P (XVECEXP (PATTERN (insn), 0, i)) = 0; 1584 } 1585} 1586 1587/* See if INSN is redundant with an insn in front of TARGET. Often this 1588 is called when INSN is a candidate for a delay slot of TARGET. 1589 DELAY_LIST are insns that will be placed in delay slots of TARGET in front 1590 of INSN. Often INSN will be redundant with an insn in a delay slot of 1591 some previous insn. This happens when we have a series of branches to the 1592 same label; in that case the first insn at the target might want to go 1593 into each of the delay slots. 1594 1595 If we are not careful, this routine can take up a significant fraction 1596 of the total compilation time (4%), but only wins rarely. Hence we 1597 speed this routine up by making two passes. The first pass goes back 1598 until it hits a label and sees if it finds an insn with an identical 1599 pattern. Only in this (relatively rare) event does it check for 1600 data conflicts. 1601 1602 We do not split insns we encounter. This could cause us not to find a 1603 redundant insn, but the cost of splitting seems greater than the possible 1604 gain in rare cases. */ 1605 1606static rtx 1607redundant_insn (rtx insn, rtx target, rtx delay_list) 1608{ 1609 rtx target_main = target; 1610 rtx ipat = PATTERN (insn); 1611 rtx trial, pat; 1612 struct resources needed, set; 1613 int i; 1614 unsigned insns_to_search; 1615 1616 /* If INSN has any REG_UNUSED notes, it can't match anything since we 1617 are allowed to not actually assign to such a register. */ 1618 if (find_reg_note (insn, REG_UNUSED, NULL_RTX) != 0) 1619 return 0; 1620 1621 /* Scan backwards looking for a match. */ 1622 for (trial = PREV_INSN (target), 1623 insns_to_search = MAX_DELAY_SLOT_INSN_SEARCH; 1624 trial && insns_to_search > 0; 1625 trial = PREV_INSN (trial), --insns_to_search) 1626 { 1627 if (LABEL_P (trial)) 1628 return 0; 1629 1630 if (! INSN_P (trial)) 1631 continue; 1632 1633 pat = PATTERN (trial); 1634 if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) 1635 continue; 1636 1637 if (GET_CODE (pat) == SEQUENCE) 1638 { 1639 /* Stop for a CALL and its delay slots because it is difficult to 1640 track its resource needs correctly. */ 1641 if (CALL_P (XVECEXP (pat, 0, 0))) 1642 return 0; 1643 1644 /* Stop for an INSN or JUMP_INSN with delayed effects and its delay 1645 slots because it is difficult to track its resource needs 1646 correctly. */ 1647 1648#ifdef INSN_SETS_ARE_DELAYED 1649 if (INSN_SETS_ARE_DELAYED (XVECEXP (pat, 0, 0))) 1650 return 0; 1651#endif 1652 1653#ifdef INSN_REFERENCES_ARE_DELAYED 1654 if (INSN_REFERENCES_ARE_DELAYED (XVECEXP (pat, 0, 0))) 1655 return 0; 1656#endif 1657 1658 /* See if any of the insns in the delay slot match, updating 1659 resource requirements as we go. */ 1660 for (i = XVECLEN (pat, 0) - 1; i > 0; i--) 1661 if (GET_CODE (XVECEXP (pat, 0, i)) == GET_CODE (insn) 1662 && rtx_equal_p (PATTERN (XVECEXP (pat, 0, i)), ipat) 1663 && ! find_reg_note (XVECEXP (pat, 0, i), REG_UNUSED, NULL_RTX)) 1664 break; 1665 1666 /* If found a match, exit this loop early. */ 1667 if (i > 0) 1668 break; 1669 } 1670 1671 else if (GET_CODE (trial) == GET_CODE (insn) && rtx_equal_p (pat, ipat) 1672 && ! find_reg_note (trial, REG_UNUSED, NULL_RTX)) 1673 break; 1674 } 1675 1676 /* If we didn't find an insn that matches, return 0. */ 1677 if (trial == 0) 1678 return 0; 1679 1680 /* See what resources this insn sets and needs. If they overlap, or 1681 if this insn references CC0, it can't be redundant. */ 1682 1683 CLEAR_RESOURCE (&needed); 1684 CLEAR_RESOURCE (&set); 1685 mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL); 1686 mark_referenced_resources (insn, &needed, 1); 1687 1688 /* If TARGET is a SEQUENCE, get the main insn. */ 1689 if (NONJUMP_INSN_P (target) && GET_CODE (PATTERN (target)) == SEQUENCE) 1690 target_main = XVECEXP (PATTERN (target), 0, 0); 1691 1692 if (resource_conflicts_p (&needed, &set) 1693#ifdef HAVE_cc0 1694 || reg_mentioned_p (cc0_rtx, ipat) 1695#endif 1696 /* The insn requiring the delay may not set anything needed or set by 1697 INSN. */ 1698 || insn_sets_resource_p (target_main, &needed, 1) 1699 || insn_sets_resource_p (target_main, &set, 1)) 1700 return 0; 1701 1702 /* Insns we pass may not set either NEEDED or SET, so merge them for 1703 simpler tests. */ 1704 needed.memory |= set.memory; 1705 needed.unch_memory |= set.unch_memory; 1706 IOR_HARD_REG_SET (needed.regs, set.regs); 1707 1708 /* This insn isn't redundant if it conflicts with an insn that either is 1709 or will be in a delay slot of TARGET. */ 1710 1711 while (delay_list) 1712 { 1713 if (insn_sets_resource_p (XEXP (delay_list, 0), &needed, 1)) 1714 return 0; 1715 delay_list = XEXP (delay_list, 1); 1716 } 1717 1718 if (NONJUMP_INSN_P (target) && GET_CODE (PATTERN (target)) == SEQUENCE) 1719 for (i = 1; i < XVECLEN (PATTERN (target), 0); i++) 1720 if (insn_sets_resource_p (XVECEXP (PATTERN (target), 0, i), &needed, 1)) 1721 return 0; 1722 1723 /* Scan backwards until we reach a label or an insn that uses something 1724 INSN sets or sets something insn uses or sets. */ 1725 1726 for (trial = PREV_INSN (target), 1727 insns_to_search = MAX_DELAY_SLOT_INSN_SEARCH; 1728 trial && !LABEL_P (trial) && insns_to_search > 0; 1729 trial = PREV_INSN (trial), --insns_to_search) 1730 { 1731 if (!INSN_P (trial)) 1732 continue; 1733 1734 pat = PATTERN (trial); 1735 if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) 1736 continue; 1737 1738 if (GET_CODE (pat) == SEQUENCE) 1739 { 1740 /* If this is a CALL_INSN and its delay slots, it is hard to track 1741 the resource needs properly, so give up. */ 1742 if (CALL_P (XVECEXP (pat, 0, 0))) 1743 return 0; 1744 1745 /* If this is an INSN or JUMP_INSN with delayed effects, it 1746 is hard to track the resource needs properly, so give up. */ 1747 1748#ifdef INSN_SETS_ARE_DELAYED 1749 if (INSN_SETS_ARE_DELAYED (XVECEXP (pat, 0, 0))) 1750 return 0; 1751#endif 1752 1753#ifdef INSN_REFERENCES_ARE_DELAYED 1754 if (INSN_REFERENCES_ARE_DELAYED (XVECEXP (pat, 0, 0))) 1755 return 0; 1756#endif 1757 1758 /* See if any of the insns in the delay slot match, updating 1759 resource requirements as we go. */ 1760 for (i = XVECLEN (pat, 0) - 1; i > 0; i--) 1761 { 1762 rtx candidate = XVECEXP (pat, 0, i); 1763 1764 /* If an insn will be annulled if the branch is false, it isn't 1765 considered as a possible duplicate insn. */ 1766 if (rtx_equal_p (PATTERN (candidate), ipat) 1767 && ! (INSN_ANNULLED_BRANCH_P (XVECEXP (pat, 0, 0)) 1768 && INSN_FROM_TARGET_P (candidate))) 1769 { 1770 /* Show that this insn will be used in the sequel. */ 1771 INSN_FROM_TARGET_P (candidate) = 0; 1772 return candidate; 1773 } 1774 1775 /* Unless this is an annulled insn from the target of a branch, 1776 we must stop if it sets anything needed or set by INSN. */ 1777 if ((! INSN_ANNULLED_BRANCH_P (XVECEXP (pat, 0, 0)) 1778 || ! INSN_FROM_TARGET_P (candidate)) 1779 && insn_sets_resource_p (candidate, &needed, 1)) 1780 return 0; 1781 } 1782 1783 /* If the insn requiring the delay slot conflicts with INSN, we 1784 must stop. */ 1785 if (insn_sets_resource_p (XVECEXP (pat, 0, 0), &needed, 1)) 1786 return 0; 1787 } 1788 else 1789 { 1790 /* See if TRIAL is the same as INSN. */ 1791 pat = PATTERN (trial); 1792 if (rtx_equal_p (pat, ipat)) 1793 return trial; 1794 1795 /* Can't go any further if TRIAL conflicts with INSN. */ 1796 if (insn_sets_resource_p (trial, &needed, 1)) 1797 return 0; 1798 } 1799 } 1800 1801 return 0; 1802} 1803 1804/* Return 1 if THREAD can only be executed in one way. If LABEL is nonzero, 1805 it is the target of the branch insn being scanned. If ALLOW_FALLTHROUGH 1806 is nonzero, we are allowed to fall into this thread; otherwise, we are 1807 not. 1808 1809 If LABEL is used more than one or we pass a label other than LABEL before 1810 finding an active insn, we do not own this thread. */ 1811 1812static int 1813own_thread_p (rtx thread, rtx label, int allow_fallthrough) 1814{ 1815 rtx active_insn; 1816 rtx insn; 1817 1818 /* We don't own the function end. */ 1819 if (thread == 0) 1820 return 0; 1821 1822 /* Get the first active insn, or THREAD, if it is an active insn. */ 1823 active_insn = next_active_insn (PREV_INSN (thread)); 1824 1825 for (insn = thread; insn != active_insn; insn = NEXT_INSN (insn)) 1826 if (LABEL_P (insn) 1827 && (insn != label || LABEL_NUSES (insn) != 1)) 1828 return 0; 1829 1830 if (allow_fallthrough) 1831 return 1; 1832 1833 /* Ensure that we reach a BARRIER before any insn or label. */ 1834 for (insn = prev_nonnote_insn (thread); 1835 insn == 0 || !BARRIER_P (insn); 1836 insn = prev_nonnote_insn (insn)) 1837 if (insn == 0 1838 || LABEL_P (insn) 1839 || (NONJUMP_INSN_P (insn) 1840 && GET_CODE (PATTERN (insn)) != USE 1841 && GET_CODE (PATTERN (insn)) != CLOBBER)) 1842 return 0; 1843 1844 return 1; 1845} 1846 1847/* Called when INSN is being moved from a location near the target of a jump. 1848 We leave a marker of the form (use (INSN)) immediately in front 1849 of WHERE for mark_target_live_regs. These markers will be deleted when 1850 reorg finishes. 1851 1852 We used to try to update the live status of registers if WHERE is at 1853 the start of a basic block, but that can't work since we may remove a 1854 BARRIER in relax_delay_slots. */ 1855 1856static void 1857update_block (rtx insn, rtx where) 1858{ 1859 /* Ignore if this was in a delay slot and it came from the target of 1860 a branch. */ 1861 if (INSN_FROM_TARGET_P (insn)) 1862 return; 1863 1864 emit_insn_before (gen_rtx_USE (VOIDmode, insn), where); 1865 1866 /* INSN might be making a value live in a block where it didn't use to 1867 be. So recompute liveness information for this block. */ 1868 1869 incr_ticks_for_insn (insn); 1870} 1871 1872/* Similar to REDIRECT_JUMP except that we update the BB_TICKS entry for 1873 the basic block containing the jump. */ 1874 1875static int 1876reorg_redirect_jump (rtx jump, rtx nlabel) 1877{ 1878 incr_ticks_for_insn (jump); 1879 return redirect_jump (jump, nlabel, 1); 1880} 1881 1882/* Called when INSN is being moved forward into a delay slot of DELAYED_INSN. 1883 We check every instruction between INSN and DELAYED_INSN for REG_DEAD notes 1884 that reference values used in INSN. If we find one, then we move the 1885 REG_DEAD note to INSN. 1886 1887 This is needed to handle the case where a later insn (after INSN) has a 1888 REG_DEAD note for a register used by INSN, and this later insn subsequently 1889 gets moved before a CODE_LABEL because it is a redundant insn. In this 1890 case, mark_target_live_regs may be confused into thinking the register 1891 is dead because it sees a REG_DEAD note immediately before a CODE_LABEL. */ 1892 1893static void 1894update_reg_dead_notes (rtx insn, rtx delayed_insn) 1895{ 1896 rtx p, link, next; 1897 1898 for (p = next_nonnote_insn (insn); p != delayed_insn; 1899 p = next_nonnote_insn (p)) 1900 for (link = REG_NOTES (p); link; link = next) 1901 { 1902 next = XEXP (link, 1); 1903 1904 if (REG_NOTE_KIND (link) != REG_DEAD 1905 || !REG_P (XEXP (link, 0))) 1906 continue; 1907 1908 if (reg_referenced_p (XEXP (link, 0), PATTERN (insn))) 1909 { 1910 /* Move the REG_DEAD note from P to INSN. */ 1911 remove_note (p, link); 1912 XEXP (link, 1) = REG_NOTES (insn); 1913 REG_NOTES (insn) = link; 1914 } 1915 } 1916} 1917 1918/* Called when an insn redundant with start_insn is deleted. If there 1919 is a REG_DEAD note for the target of start_insn between start_insn 1920 and stop_insn, then the REG_DEAD note needs to be deleted since the 1921 value no longer dies there. 1922 1923 If the REG_DEAD note isn't deleted, then mark_target_live_regs may be 1924 confused into thinking the register is dead. */ 1925 1926static void 1927fix_reg_dead_note (rtx start_insn, rtx stop_insn) 1928{ 1929 rtx p, link, next; 1930 1931 for (p = next_nonnote_insn (start_insn); p != stop_insn; 1932 p = next_nonnote_insn (p)) 1933 for (link = REG_NOTES (p); link; link = next) 1934 { 1935 next = XEXP (link, 1); 1936 1937 if (REG_NOTE_KIND (link) != REG_DEAD 1938 || !REG_P (XEXP (link, 0))) 1939 continue; 1940 1941 if (reg_set_p (XEXP (link, 0), PATTERN (start_insn))) 1942 { 1943 remove_note (p, link); 1944 return; 1945 } 1946 } 1947} 1948 1949/* Delete any REG_UNUSED notes that exist on INSN but not on REDUNDANT_INSN. 1950 1951 This handles the case of udivmodXi4 instructions which optimize their 1952 output depending on whether any REG_UNUSED notes are present. 1953 we must make sure that INSN calculates as many results as REDUNDANT_INSN 1954 does. */ 1955 1956static void 1957update_reg_unused_notes (rtx insn, rtx redundant_insn) 1958{ 1959 rtx link, next; 1960 1961 for (link = REG_NOTES (insn); link; link = next) 1962 { 1963 next = XEXP (link, 1); 1964 1965 if (REG_NOTE_KIND (link) != REG_UNUSED 1966 || !REG_P (XEXP (link, 0))) 1967 continue; 1968 1969 if (! find_regno_note (redundant_insn, REG_UNUSED, 1970 REGNO (XEXP (link, 0)))) 1971 remove_note (insn, link); 1972 } 1973} 1974 1975/* Scan a function looking for insns that need a delay slot and find insns to 1976 put into the delay slot. 1977 1978 NON_JUMPS_P is nonzero if we are to only try to fill non-jump insns (such 1979 as calls). We do these first since we don't want jump insns (that are 1980 easier to fill) to get the only insns that could be used for non-jump insns. 1981 When it is zero, only try to fill JUMP_INSNs. 1982 1983 When slots are filled in this manner, the insns (including the 1984 delay_insn) are put together in a SEQUENCE rtx. In this fashion, 1985 it is possible to tell whether a delay slot has really been filled 1986 or not. `final' knows how to deal with this, by communicating 1987 through FINAL_SEQUENCE. */ 1988 1989static void 1990fill_simple_delay_slots (int non_jumps_p) 1991{ 1992 rtx insn, pat, trial, next_trial; 1993 int i; 1994 int num_unfilled_slots = unfilled_slots_next - unfilled_slots_base; 1995 struct resources needed, set; 1996 int slots_to_fill, slots_filled; 1997 rtx delay_list; 1998 1999 for (i = 0; i < num_unfilled_slots; i++) 2000 { 2001 int flags; 2002 /* Get the next insn to fill. If it has already had any slots assigned, 2003 we can't do anything with it. Maybe we'll improve this later. */ 2004 2005 insn = unfilled_slots_base[i]; 2006 if (insn == 0 2007 || INSN_DELETED_P (insn) 2008 || (NONJUMP_INSN_P (insn) 2009 && GET_CODE (PATTERN (insn)) == SEQUENCE) 2010 || (JUMP_P (insn) && non_jumps_p) 2011 || (!JUMP_P (insn) && ! non_jumps_p)) 2012 continue; 2013 2014 /* It may have been that this insn used to need delay slots, but 2015 now doesn't; ignore in that case. This can happen, for example, 2016 on the HP PA RISC, where the number of delay slots depends on 2017 what insns are nearby. */ 2018 slots_to_fill = num_delay_slots (insn); 2019 2020 /* Some machine description have defined instructions to have 2021 delay slots only in certain circumstances which may depend on 2022 nearby insns (which change due to reorg's actions). 2023 2024 For example, the PA port normally has delay slots for unconditional 2025 jumps. 2026 2027 However, the PA port claims such jumps do not have a delay slot 2028 if they are immediate successors of certain CALL_INSNs. This 2029 allows the port to favor filling the delay slot of the call with 2030 the unconditional jump. */ 2031 if (slots_to_fill == 0) 2032 continue; 2033 2034 /* This insn needs, or can use, some delay slots. SLOTS_TO_FILL 2035 says how many. After initialization, first try optimizing 2036 2037 call _foo call _foo 2038 nop add %o7,.-L1,%o7 2039 b,a L1 2040 nop 2041 2042 If this case applies, the delay slot of the call is filled with 2043 the unconditional jump. This is done first to avoid having the 2044 delay slot of the call filled in the backward scan. Also, since 2045 the unconditional jump is likely to also have a delay slot, that 2046 insn must exist when it is subsequently scanned. 2047 2048 This is tried on each insn with delay slots as some machines 2049 have insns which perform calls, but are not represented as 2050 CALL_INSNs. */ 2051 2052 slots_filled = 0; 2053 delay_list = 0; 2054 2055 if (JUMP_P (insn)) 2056 flags = get_jump_flags (insn, JUMP_LABEL (insn)); 2057 else 2058 flags = get_jump_flags (insn, NULL_RTX); 2059 2060 if ((trial = next_active_insn (insn)) 2061 && JUMP_P (trial) 2062 && simplejump_p (trial) 2063 && eligible_for_delay (insn, slots_filled, trial, flags) 2064 && no_labels_between_p (insn, trial) 2065 && ! can_throw_internal (trial)) 2066 { 2067 rtx *tmp; 2068 slots_filled++; 2069 delay_list = add_to_delay_list (trial, delay_list); 2070 2071 /* TRIAL may have had its delay slot filled, then unfilled. When 2072 the delay slot is unfilled, TRIAL is placed back on the unfilled 2073 slots obstack. Unfortunately, it is placed on the end of the 2074 obstack, not in its original location. Therefore, we must search 2075 from entry i + 1 to the end of the unfilled slots obstack to 2076 try and find TRIAL. */ 2077 tmp = &unfilled_slots_base[i + 1]; 2078 while (*tmp != trial && tmp != unfilled_slots_next) 2079 tmp++; 2080 2081 /* Remove the unconditional jump from consideration for delay slot 2082 filling and unthread it. */ 2083 if (*tmp == trial) 2084 *tmp = 0; 2085 { 2086 rtx next = NEXT_INSN (trial); 2087 rtx prev = PREV_INSN (trial); 2088 if (prev) 2089 NEXT_INSN (prev) = next; 2090 if (next) 2091 PREV_INSN (next) = prev; 2092 } 2093 } 2094 2095 /* Now, scan backwards from the insn to search for a potential 2096 delay-slot candidate. Stop searching when a label or jump is hit. 2097 2098 For each candidate, if it is to go into the delay slot (moved 2099 forward in execution sequence), it must not need or set any resources 2100 that were set by later insns and must not set any resources that 2101 are needed for those insns. 2102 2103 The delay slot insn itself sets resources unless it is a call 2104 (in which case the called routine, not the insn itself, is doing 2105 the setting). */ 2106 2107 if (slots_filled < slots_to_fill) 2108 { 2109 CLEAR_RESOURCE (&needed); 2110 CLEAR_RESOURCE (&set); 2111 mark_set_resources (insn, &set, 0, MARK_SRC_DEST); 2112 mark_referenced_resources (insn, &needed, 0); 2113 2114 for (trial = prev_nonnote_insn (insn); ! stop_search_p (trial, 1); 2115 trial = next_trial) 2116 { 2117 next_trial = prev_nonnote_insn (trial); 2118 2119 /* This must be an INSN or CALL_INSN. */ 2120 pat = PATTERN (trial); 2121 2122 /* USE and CLOBBER at this level was just for flow; ignore it. */ 2123 if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) 2124 continue; 2125 2126 /* Check for resource conflict first, to avoid unnecessary 2127 splitting. */ 2128 if (! insn_references_resource_p (trial, &set, 1) 2129 && ! insn_sets_resource_p (trial, &set, 1) 2130 && ! insn_sets_resource_p (trial, &needed, 1) 2131#ifdef HAVE_cc0 2132 /* Can't separate set of cc0 from its use. */ 2133 && ! (reg_mentioned_p (cc0_rtx, pat) && ! sets_cc0_p (pat)) 2134#endif 2135 && ! can_throw_internal (trial)) 2136 { 2137 trial = try_split (pat, trial, 1); 2138 next_trial = prev_nonnote_insn (trial); 2139 if (eligible_for_delay (insn, slots_filled, trial, flags)) 2140 { 2141 /* In this case, we are searching backward, so if we 2142 find insns to put on the delay list, we want 2143 to put them at the head, rather than the 2144 tail, of the list. */ 2145 2146 update_reg_dead_notes (trial, insn); 2147 delay_list = gen_rtx_INSN_LIST (VOIDmode, 2148 trial, delay_list); 2149 update_block (trial, trial); 2150 delete_related_insns (trial); 2151 if (slots_to_fill == ++slots_filled) 2152 break; 2153 continue; 2154 } 2155 } 2156 2157 mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL); 2158 mark_referenced_resources (trial, &needed, 1); 2159 } 2160 } 2161 2162 /* If all needed slots haven't been filled, we come here. */ 2163 2164 /* Try to optimize case of jumping around a single insn. */ 2165#if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS) 2166 if (slots_filled != slots_to_fill 2167 && delay_list == 0 2168 && JUMP_P (insn) 2169 && (condjump_p (insn) || condjump_in_parallel_p (insn))) 2170 { 2171 delay_list = optimize_skip (insn); 2172 if (delay_list) 2173 slots_filled += 1; 2174 } 2175#endif 2176 2177 /* Try to get insns from beyond the insn needing the delay slot. 2178 These insns can neither set or reference resources set in insns being 2179 skipped, cannot set resources in the insn being skipped, and, if this 2180 is a CALL_INSN (or a CALL_INSN is passed), cannot trap (because the 2181 call might not return). 2182 2183 There used to be code which continued past the target label if 2184 we saw all uses of the target label. This code did not work, 2185 because it failed to account for some instructions which were 2186 both annulled and marked as from the target. This can happen as a 2187 result of optimize_skip. Since this code was redundant with 2188 fill_eager_delay_slots anyways, it was just deleted. */ 2189 2190 if (slots_filled != slots_to_fill 2191 /* If this instruction could throw an exception which is 2192 caught in the same function, then it's not safe to fill 2193 the delay slot with an instruction from beyond this 2194 point. For example, consider: 2195 2196 int i = 2; 2197 2198 try { 2199 f(); 2200 i = 3; 2201 } catch (...) {} 2202 2203 return i; 2204 2205 Even though `i' is a local variable, we must be sure not 2206 to put `i = 3' in the delay slot if `f' might throw an 2207 exception. 2208 2209 Presumably, we should also check to see if we could get 2210 back to this function via `setjmp'. */ 2211 && ! can_throw_internal (insn) 2212 && (!JUMP_P (insn) 2213 || ((condjump_p (insn) || condjump_in_parallel_p (insn)) 2214 && ! simplejump_p (insn) 2215 && JUMP_LABEL (insn) != 0))) 2216 { 2217 /* Invariant: If insn is a JUMP_INSN, the insn's jump 2218 label. Otherwise, zero. */ 2219 rtx target = 0; 2220 int maybe_never = 0; 2221 rtx pat, trial_delay; 2222 2223 CLEAR_RESOURCE (&needed); 2224 CLEAR_RESOURCE (&set); 2225 2226 if (CALL_P (insn)) 2227 { 2228 mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL); 2229 mark_referenced_resources (insn, &needed, 1); 2230 maybe_never = 1; 2231 } 2232 else 2233 { 2234 mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL); 2235 mark_referenced_resources (insn, &needed, 1); 2236 if (JUMP_P (insn)) 2237 target = JUMP_LABEL (insn); 2238 } 2239 2240 if (target == 0) 2241 for (trial = next_nonnote_insn (insn); trial; trial = next_trial) 2242 { 2243 next_trial = next_nonnote_insn (trial); 2244 2245 if (LABEL_P (trial) 2246 || BARRIER_P (trial)) 2247 break; 2248 2249 /* We must have an INSN, JUMP_INSN, or CALL_INSN. */ 2250 pat = PATTERN (trial); 2251 2252 /* Stand-alone USE and CLOBBER are just for flow. */ 2253 if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) 2254 continue; 2255 2256 /* If this already has filled delay slots, get the insn needing 2257 the delay slots. */ 2258 if (GET_CODE (pat) == SEQUENCE) 2259 trial_delay = XVECEXP (pat, 0, 0); 2260 else 2261 trial_delay = trial; 2262 2263 /* Stop our search when seeing an unconditional jump. */ 2264 if (JUMP_P (trial_delay)) 2265 break; 2266 2267 /* See if we have a resource problem before we try to 2268 split. */ 2269 if (GET_CODE (pat) != SEQUENCE 2270 && ! insn_references_resource_p (trial, &set, 1) 2271 && ! insn_sets_resource_p (trial, &set, 1) 2272 && ! insn_sets_resource_p (trial, &needed, 1) 2273#ifdef HAVE_cc0 2274 && ! (reg_mentioned_p (cc0_rtx, pat) && ! sets_cc0_p (pat)) 2275#endif 2276 && ! (maybe_never && may_trap_or_fault_p (pat)) 2277 && (trial = try_split (pat, trial, 0)) 2278 && eligible_for_delay (insn, slots_filled, trial, flags) 2279 && ! can_throw_internal(trial)) 2280 { 2281 next_trial = next_nonnote_insn (trial); 2282 delay_list = add_to_delay_list (trial, delay_list); 2283 2284#ifdef HAVE_cc0 2285 if (reg_mentioned_p (cc0_rtx, pat)) 2286 link_cc0_insns (trial); 2287#endif 2288 2289 delete_related_insns (trial); 2290 if (slots_to_fill == ++slots_filled) 2291 break; 2292 continue; 2293 } 2294 2295 mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL); 2296 mark_referenced_resources (trial, &needed, 1); 2297 2298 /* Ensure we don't put insns between the setting of cc and the 2299 comparison by moving a setting of cc into an earlier delay 2300 slot since these insns could clobber the condition code. */ 2301 set.cc = 1; 2302 2303 /* If this is a call or jump, we might not get here. */ 2304 if (CALL_P (trial_delay) 2305 || JUMP_P (trial_delay)) 2306 maybe_never = 1; 2307 } 2308 2309 /* If there are slots left to fill and our search was stopped by an 2310 unconditional branch, try the insn at the branch target. We can 2311 redirect the branch if it works. 2312 2313 Don't do this if the insn at the branch target is a branch. */ 2314 if (slots_to_fill != slots_filled 2315 && trial 2316 && JUMP_P (trial) 2317 && simplejump_p (trial) 2318 && (target == 0 || JUMP_LABEL (trial) == target) 2319 && (next_trial = next_active_insn (JUMP_LABEL (trial))) != 0 2320 && ! (NONJUMP_INSN_P (next_trial) 2321 && GET_CODE (PATTERN (next_trial)) == SEQUENCE) 2322 && !JUMP_P (next_trial) 2323 && ! insn_references_resource_p (next_trial, &set, 1) 2324 && ! insn_sets_resource_p (next_trial, &set, 1) 2325 && ! insn_sets_resource_p (next_trial, &needed, 1) 2326#ifdef HAVE_cc0 2327 && ! reg_mentioned_p (cc0_rtx, PATTERN (next_trial)) 2328#endif 2329 && ! (maybe_never && may_trap_or_fault_p (PATTERN (next_trial))) 2330 && (next_trial = try_split (PATTERN (next_trial), next_trial, 0)) 2331 && eligible_for_delay (insn, slots_filled, next_trial, flags) 2332 && ! can_throw_internal (trial)) 2333 { 2334 /* See comment in relax_delay_slots about necessity of using 2335 next_real_insn here. */ 2336 rtx new_label = next_real_insn (next_trial); 2337 2338 if (new_label != 0) 2339 new_label = get_label_before (new_label); 2340 else 2341 new_label = find_end_label (); 2342 2343 if (new_label) 2344 { 2345 delay_list 2346 = add_to_delay_list (copy_rtx (next_trial), delay_list); 2347 slots_filled++; 2348 reorg_redirect_jump (trial, new_label); 2349 2350 /* If we merged because we both jumped to the same place, 2351 redirect the original insn also. */ 2352 if (target) 2353 reorg_redirect_jump (insn, new_label); 2354 } 2355 } 2356 } 2357 2358 /* If this is an unconditional jump, then try to get insns from the 2359 target of the jump. */ 2360 if (JUMP_P (insn) 2361 && simplejump_p (insn) 2362 && slots_filled != slots_to_fill) 2363 delay_list 2364 = fill_slots_from_thread (insn, const_true_rtx, 2365 next_active_insn (JUMP_LABEL (insn)), 2366 NULL, 1, 1, 2367 own_thread_p (JUMP_LABEL (insn), 2368 JUMP_LABEL (insn), 0), 2369 slots_to_fill, &slots_filled, 2370 delay_list); 2371 2372 if (delay_list) 2373 unfilled_slots_base[i] 2374 = emit_delay_sequence (insn, delay_list, slots_filled); 2375 2376 if (slots_to_fill == slots_filled) 2377 unfilled_slots_base[i] = 0; 2378 2379 note_delay_statistics (slots_filled, 0); 2380 } 2381 2382#ifdef DELAY_SLOTS_FOR_EPILOGUE 2383 /* See if the epilogue needs any delay slots. Try to fill them if so. 2384 The only thing we can do is scan backwards from the end of the 2385 function. If we did this in a previous pass, it is incorrect to do it 2386 again. */ 2387 if (current_function_epilogue_delay_list) 2388 return; 2389 2390 slots_to_fill = DELAY_SLOTS_FOR_EPILOGUE; 2391 if (slots_to_fill == 0) 2392 return; 2393 2394 slots_filled = 0; 2395 CLEAR_RESOURCE (&set); 2396 2397 /* The frame pointer and stack pointer are needed at the beginning of 2398 the epilogue, so instructions setting them can not be put in the 2399 epilogue delay slot. However, everything else needed at function 2400 end is safe, so we don't want to use end_of_function_needs here. */ 2401 CLEAR_RESOURCE (&needed); 2402 if (frame_pointer_needed) 2403 { 2404 SET_HARD_REG_BIT (needed.regs, FRAME_POINTER_REGNUM); 2405#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM 2406 SET_HARD_REG_BIT (needed.regs, HARD_FRAME_POINTER_REGNUM); 2407#endif 2408 if (! EXIT_IGNORE_STACK 2409 || current_function_sp_is_unchanging) 2410 SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM); 2411 } 2412 else 2413 SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM); 2414 2415#ifdef EPILOGUE_USES 2416 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) 2417 { 2418 if (EPILOGUE_USES (i)) 2419 SET_HARD_REG_BIT (needed.regs, i); 2420 } 2421#endif 2422 2423 for (trial = get_last_insn (); ! stop_search_p (trial, 1); 2424 trial = PREV_INSN (trial)) 2425 { 2426 if (NOTE_P (trial)) 2427 continue; 2428 pat = PATTERN (trial); 2429 if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) 2430 continue; 2431 2432 if (! insn_references_resource_p (trial, &set, 1) 2433 && ! insn_sets_resource_p (trial, &needed, 1) 2434 && ! insn_sets_resource_p (trial, &set, 1) 2435#ifdef HAVE_cc0 2436 /* Don't want to mess with cc0 here. */ 2437 && ! reg_mentioned_p (cc0_rtx, pat) 2438#endif 2439 && ! can_throw_internal (trial)) 2440 { 2441 trial = try_split (pat, trial, 1); 2442 if (ELIGIBLE_FOR_EPILOGUE_DELAY (trial, slots_filled)) 2443 { 2444 /* Here as well we are searching backward, so put the 2445 insns we find on the head of the list. */ 2446 2447 current_function_epilogue_delay_list 2448 = gen_rtx_INSN_LIST (VOIDmode, trial, 2449 current_function_epilogue_delay_list); 2450 mark_end_of_function_resources (trial, 1); 2451 update_block (trial, trial); 2452 delete_related_insns (trial); 2453 2454 /* Clear deleted bit so final.c will output the insn. */ 2455 INSN_DELETED_P (trial) = 0; 2456 2457 if (slots_to_fill == ++slots_filled) 2458 break; 2459 continue; 2460 } 2461 } 2462 2463 mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL); 2464 mark_referenced_resources (trial, &needed, 1); 2465 } 2466 2467 note_delay_statistics (slots_filled, 0); 2468#endif 2469} 2470 2471/* Try to find insns to place in delay slots. 2472 2473 INSN is the jump needing SLOTS_TO_FILL delay slots. It tests CONDITION 2474 or is an unconditional branch if CONDITION is const_true_rtx. 2475 *PSLOTS_FILLED is updated with the number of slots that we have filled. 2476 2477 THREAD is a flow-of-control, either the insns to be executed if the 2478 branch is true or if the branch is false, THREAD_IF_TRUE says which. 2479 2480 OPPOSITE_THREAD is the thread in the opposite direction. It is used 2481 to see if any potential delay slot insns set things needed there. 2482 2483 LIKELY is nonzero if it is extremely likely that the branch will be 2484 taken and THREAD_IF_TRUE is set. This is used for the branch at the 2485 end of a loop back up to the top. 2486 2487 OWN_THREAD and OWN_OPPOSITE_THREAD are true if we are the only user of the 2488 thread. I.e., it is the fallthrough code of our jump or the target of the 2489 jump when we are the only jump going there. 2490 2491 If OWN_THREAD is false, it must be the "true" thread of a jump. In that 2492 case, we can only take insns from the head of the thread for our delay 2493 slot. We then adjust the jump to point after the insns we have taken. */ 2494 2495static rtx 2496fill_slots_from_thread (rtx insn, rtx condition, rtx thread, 2497 rtx opposite_thread, int likely, int thread_if_true, 2498 int own_thread, int slots_to_fill, 2499 int *pslots_filled, rtx delay_list) 2500{ 2501 rtx new_thread; 2502 struct resources opposite_needed, set, needed; 2503 rtx trial; 2504 int lose = 0; 2505 int must_annul = 0; 2506 int flags; 2507 2508 /* Validate our arguments. */ 2509 gcc_assert(condition != const_true_rtx || thread_if_true); 2510 gcc_assert(own_thread || thread_if_true); 2511 2512 flags = get_jump_flags (insn, JUMP_LABEL (insn)); 2513 2514 /* If our thread is the end of subroutine, we can't get any delay 2515 insns from that. */ 2516 if (thread == 0) 2517 return delay_list; 2518 2519 /* If this is an unconditional branch, nothing is needed at the 2520 opposite thread. Otherwise, compute what is needed there. */ 2521 if (condition == const_true_rtx) 2522 CLEAR_RESOURCE (&opposite_needed); 2523 else 2524 mark_target_live_regs (get_insns (), opposite_thread, &opposite_needed); 2525 2526 /* If the insn at THREAD can be split, do it here to avoid having to 2527 update THREAD and NEW_THREAD if it is done in the loop below. Also 2528 initialize NEW_THREAD. */ 2529 2530 new_thread = thread = try_split (PATTERN (thread), thread, 0); 2531 2532 /* Scan insns at THREAD. We are looking for an insn that can be removed 2533 from THREAD (it neither sets nor references resources that were set 2534 ahead of it and it doesn't set anything needs by the insns ahead of 2535 it) and that either can be placed in an annulling insn or aren't 2536 needed at OPPOSITE_THREAD. */ 2537 2538 CLEAR_RESOURCE (&needed); 2539 CLEAR_RESOURCE (&set); 2540 2541 /* If we do not own this thread, we must stop as soon as we find 2542 something that we can't put in a delay slot, since all we can do 2543 is branch into THREAD at a later point. Therefore, labels stop 2544 the search if this is not the `true' thread. */ 2545 2546 for (trial = thread; 2547 ! stop_search_p (trial, ! thread_if_true) && (! lose || own_thread); 2548 trial = next_nonnote_insn (trial)) 2549 { 2550 rtx pat, old_trial; 2551 2552 /* If we have passed a label, we no longer own this thread. */ 2553 if (LABEL_P (trial)) 2554 { 2555 own_thread = 0; 2556 continue; 2557 } 2558 2559 pat = PATTERN (trial); 2560 if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) 2561 continue; 2562 2563 /* If TRIAL conflicts with the insns ahead of it, we lose. Also, 2564 don't separate or copy insns that set and use CC0. */ 2565 if (! insn_references_resource_p (trial, &set, 1) 2566 && ! insn_sets_resource_p (trial, &set, 1) 2567 && ! insn_sets_resource_p (trial, &needed, 1) 2568#ifdef HAVE_cc0 2569 && ! (reg_mentioned_p (cc0_rtx, pat) 2570 && (! own_thread || ! sets_cc0_p (pat))) 2571#endif 2572 && ! can_throw_internal (trial)) 2573 { 2574 rtx prior_insn; 2575 2576 /* If TRIAL is redundant with some insn before INSN, we don't 2577 actually need to add it to the delay list; we can merely pretend 2578 we did. */ 2579 if ((prior_insn = redundant_insn (trial, insn, delay_list))) 2580 { 2581 fix_reg_dead_note (prior_insn, insn); 2582 if (own_thread) 2583 { 2584 update_block (trial, thread); 2585 if (trial == thread) 2586 { 2587 thread = next_active_insn (thread); 2588 if (new_thread == trial) 2589 new_thread = thread; 2590 } 2591 2592 delete_related_insns (trial); 2593 } 2594 else 2595 { 2596 update_reg_unused_notes (prior_insn, trial); 2597 new_thread = next_active_insn (trial); 2598 } 2599 2600 continue; 2601 } 2602 2603 /* There are two ways we can win: If TRIAL doesn't set anything 2604 needed at the opposite thread and can't trap, or if it can 2605 go into an annulled delay slot. */ 2606 if (!must_annul 2607 && (condition == const_true_rtx 2608 || (! insn_sets_resource_p (trial, &opposite_needed, 1) 2609 && ! may_trap_or_fault_p (pat)))) 2610 { 2611 old_trial = trial; 2612 trial = try_split (pat, trial, 0); 2613 if (new_thread == old_trial) 2614 new_thread = trial; 2615 if (thread == old_trial) 2616 thread = trial; 2617 pat = PATTERN (trial); 2618 if (eligible_for_delay (insn, *pslots_filled, trial, flags)) 2619 goto winner; 2620 } 2621 else if (0 2622#ifdef ANNUL_IFTRUE_SLOTS 2623 || ! thread_if_true 2624#endif 2625#ifdef ANNUL_IFFALSE_SLOTS 2626 || thread_if_true 2627#endif 2628 ) 2629 { 2630 old_trial = trial; 2631 trial = try_split (pat, trial, 0); 2632 if (new_thread == old_trial) 2633 new_thread = trial; 2634 if (thread == old_trial) 2635 thread = trial; 2636 pat = PATTERN (trial); 2637 if ((must_annul || delay_list == NULL) && (thread_if_true 2638 ? check_annul_list_true_false (0, delay_list) 2639 && eligible_for_annul_false (insn, *pslots_filled, trial, flags) 2640 : check_annul_list_true_false (1, delay_list) 2641 && eligible_for_annul_true (insn, *pslots_filled, trial, flags))) 2642 { 2643 rtx temp; 2644 2645 must_annul = 1; 2646 winner: 2647 2648#ifdef HAVE_cc0 2649 if (reg_mentioned_p (cc0_rtx, pat)) 2650 link_cc0_insns (trial); 2651#endif 2652 2653 /* If we own this thread, delete the insn. If this is the 2654 destination of a branch, show that a basic block status 2655 may have been updated. In any case, mark the new 2656 starting point of this thread. */ 2657 if (own_thread) 2658 { 2659 rtx note; 2660 2661 update_block (trial, thread); 2662 if (trial == thread) 2663 { 2664 thread = next_active_insn (thread); 2665 if (new_thread == trial) 2666 new_thread = thread; 2667 } 2668 2669 /* We are moving this insn, not deleting it. We must 2670 temporarily increment the use count on any referenced 2671 label lest it be deleted by delete_related_insns. */ 2672 note = find_reg_note (trial, REG_LABEL, 0); 2673 /* REG_LABEL could be NOTE_INSN_DELETED_LABEL too. */ 2674 if (note && LABEL_P (XEXP (note, 0))) 2675 LABEL_NUSES (XEXP (note, 0))++; 2676 2677 delete_related_insns (trial); 2678 2679 if (note && LABEL_P (XEXP (note, 0))) 2680 LABEL_NUSES (XEXP (note, 0))--; 2681 } 2682 else 2683 new_thread = next_active_insn (trial); 2684 2685 temp = own_thread ? trial : copy_rtx (trial); 2686 if (thread_if_true) 2687 INSN_FROM_TARGET_P (temp) = 1; 2688 2689 delay_list = add_to_delay_list (temp, delay_list); 2690 2691 if (slots_to_fill == ++(*pslots_filled)) 2692 { 2693 /* Even though we have filled all the slots, we 2694 may be branching to a location that has a 2695 redundant insn. Skip any if so. */ 2696 while (new_thread && ! own_thread 2697 && ! insn_sets_resource_p (new_thread, &set, 1) 2698 && ! insn_sets_resource_p (new_thread, &needed, 1) 2699 && ! insn_references_resource_p (new_thread, 2700 &set, 1) 2701 && (prior_insn 2702 = redundant_insn (new_thread, insn, 2703 delay_list))) 2704 { 2705 /* We know we do not own the thread, so no need 2706 to call update_block and delete_insn. */ 2707 fix_reg_dead_note (prior_insn, insn); 2708 update_reg_unused_notes (prior_insn, new_thread); 2709 new_thread = next_active_insn (new_thread); 2710 } 2711 break; 2712 } 2713 2714 continue; 2715 } 2716 } 2717 } 2718 2719 /* This insn can't go into a delay slot. */ 2720 lose = 1; 2721 mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL); 2722 mark_referenced_resources (trial, &needed, 1); 2723 2724 /* Ensure we don't put insns between the setting of cc and the comparison 2725 by moving a setting of cc into an earlier delay slot since these insns 2726 could clobber the condition code. */ 2727 set.cc = 1; 2728 2729 /* If this insn is a register-register copy and the next insn has 2730 a use of our destination, change it to use our source. That way, 2731 it will become a candidate for our delay slot the next time 2732 through this loop. This case occurs commonly in loops that 2733 scan a list. 2734 2735 We could check for more complex cases than those tested below, 2736 but it doesn't seem worth it. It might also be a good idea to try 2737 to swap the two insns. That might do better. 2738 2739 We can't do this if the next insn modifies our destination, because 2740 that would make the replacement into the insn invalid. We also can't 2741 do this if it modifies our source, because it might be an earlyclobber 2742 operand. This latter test also prevents updating the contents of 2743 a PRE_INC. We also can't do this if there's overlap of source and 2744 destination. Overlap may happen for larger-than-register-size modes. */ 2745 2746 if (NONJUMP_INSN_P (trial) && GET_CODE (pat) == SET 2747 && REG_P (SET_SRC (pat)) 2748 && REG_P (SET_DEST (pat)) 2749 && !reg_overlap_mentioned_p (SET_DEST (pat), SET_SRC (pat))) 2750 { 2751 rtx next = next_nonnote_insn (trial); 2752 2753 if (next && NONJUMP_INSN_P (next) 2754 && GET_CODE (PATTERN (next)) != USE 2755 && ! reg_set_p (SET_DEST (pat), next) 2756 && ! reg_set_p (SET_SRC (pat), next) 2757 && reg_referenced_p (SET_DEST (pat), PATTERN (next)) 2758 && ! modified_in_p (SET_DEST (pat), next)) 2759 validate_replace_rtx (SET_DEST (pat), SET_SRC (pat), next); 2760 } 2761 } 2762 2763 /* If we stopped on a branch insn that has delay slots, see if we can 2764 steal some of the insns in those slots. */ 2765 if (trial && NONJUMP_INSN_P (trial) 2766 && GET_CODE (PATTERN (trial)) == SEQUENCE 2767 && JUMP_P (XVECEXP (PATTERN (trial), 0, 0))) 2768 { 2769 /* If this is the `true' thread, we will want to follow the jump, 2770 so we can only do this if we have taken everything up to here. */ 2771 if (thread_if_true && trial == new_thread) 2772 { 2773 delay_list 2774 = steal_delay_list_from_target (insn, condition, PATTERN (trial), 2775 delay_list, &set, &needed, 2776 &opposite_needed, slots_to_fill, 2777 pslots_filled, &must_annul, 2778 &new_thread); 2779 /* If we owned the thread and are told that it branched 2780 elsewhere, make sure we own the thread at the new location. */ 2781 if (own_thread && trial != new_thread) 2782 own_thread = own_thread_p (new_thread, new_thread, 0); 2783 } 2784 else if (! thread_if_true) 2785 delay_list 2786 = steal_delay_list_from_fallthrough (insn, condition, 2787 PATTERN (trial), 2788 delay_list, &set, &needed, 2789 &opposite_needed, slots_to_fill, 2790 pslots_filled, &must_annul); 2791 } 2792 2793 /* If we haven't found anything for this delay slot and it is very 2794 likely that the branch will be taken, see if the insn at our target 2795 increments or decrements a register with an increment that does not 2796 depend on the destination register. If so, try to place the opposite 2797 arithmetic insn after the jump insn and put the arithmetic insn in the 2798 delay slot. If we can't do this, return. */ 2799 if (delay_list == 0 && likely && new_thread 2800 && NONJUMP_INSN_P (new_thread) 2801 && GET_CODE (PATTERN (new_thread)) != ASM_INPUT 2802 && asm_noperands (PATTERN (new_thread)) < 0) 2803 { 2804 rtx pat = PATTERN (new_thread); 2805 rtx dest; 2806 rtx src; 2807 2808 trial = new_thread; 2809 pat = PATTERN (trial); 2810 2811 if (!NONJUMP_INSN_P (trial) 2812 || GET_CODE (pat) != SET 2813 || ! eligible_for_delay (insn, 0, trial, flags) 2814 || can_throw_internal (trial)) 2815 return 0; 2816 2817 dest = SET_DEST (pat), src = SET_SRC (pat); 2818 if ((GET_CODE (src) == PLUS || GET_CODE (src) == MINUS) 2819 && rtx_equal_p (XEXP (src, 0), dest) 2820 && (!FLOAT_MODE_P (GET_MODE (src)) 2821 || flag_unsafe_math_optimizations) 2822 && ! reg_overlap_mentioned_p (dest, XEXP (src, 1)) 2823 && ! side_effects_p (pat)) 2824 { 2825 rtx other = XEXP (src, 1); 2826 rtx new_arith; 2827 rtx ninsn; 2828 2829 /* If this is a constant adjustment, use the same code with 2830 the negated constant. Otherwise, reverse the sense of the 2831 arithmetic. */ 2832 if (GET_CODE (other) == CONST_INT) 2833 new_arith = gen_rtx_fmt_ee (GET_CODE (src), GET_MODE (src), dest, 2834 negate_rtx (GET_MODE (src), other)); 2835 else 2836 new_arith = gen_rtx_fmt_ee (GET_CODE (src) == PLUS ? MINUS : PLUS, 2837 GET_MODE (src), dest, other); 2838 2839 ninsn = emit_insn_after (gen_rtx_SET (VOIDmode, dest, new_arith), 2840 insn); 2841 2842 if (recog_memoized (ninsn) < 0 2843 || (extract_insn (ninsn), ! constrain_operands (1))) 2844 { 2845 delete_related_insns (ninsn); 2846 return 0; 2847 } 2848 2849 if (own_thread) 2850 { 2851 update_block (trial, thread); 2852 if (trial == thread) 2853 { 2854 thread = next_active_insn (thread); 2855 if (new_thread == trial) 2856 new_thread = thread; 2857 } 2858 delete_related_insns (trial); 2859 } 2860 else 2861 new_thread = next_active_insn (trial); 2862 2863 ninsn = own_thread ? trial : copy_rtx (trial); 2864 if (thread_if_true) 2865 INSN_FROM_TARGET_P (ninsn) = 1; 2866 2867 delay_list = add_to_delay_list (ninsn, NULL_RTX); 2868 (*pslots_filled)++; 2869 } 2870 } 2871 2872 if (delay_list && must_annul) 2873 INSN_ANNULLED_BRANCH_P (insn) = 1; 2874 2875 /* If we are to branch into the middle of this thread, find an appropriate 2876 label or make a new one if none, and redirect INSN to it. If we hit the 2877 end of the function, use the end-of-function label. */ 2878 if (new_thread != thread) 2879 { 2880 rtx label; 2881 2882 gcc_assert (thread_if_true); 2883 2884 if (new_thread && JUMP_P (new_thread) 2885 && (simplejump_p (new_thread) 2886 || GET_CODE (PATTERN (new_thread)) == RETURN) 2887 && redirect_with_delay_list_safe_p (insn, 2888 JUMP_LABEL (new_thread), 2889 delay_list)) 2890 new_thread = follow_jumps (JUMP_LABEL (new_thread)); 2891 2892 if (new_thread == 0) 2893 label = find_end_label (); 2894 else if (LABEL_P (new_thread)) 2895 label = new_thread; 2896 else 2897 label = get_label_before (new_thread); 2898 2899 if (label) 2900 reorg_redirect_jump (insn, label); 2901 } 2902 2903 return delay_list; 2904} 2905 2906/* Make another attempt to find insns to place in delay slots. 2907 2908 We previously looked for insns located in front of the delay insn 2909 and, for non-jump delay insns, located behind the delay insn. 2910 2911 Here only try to schedule jump insns and try to move insns from either 2912 the target or the following insns into the delay slot. If annulling is 2913 supported, we will be likely to do this. Otherwise, we can do this only 2914 if safe. */ 2915 2916static void 2917fill_eager_delay_slots (void) 2918{ 2919 rtx insn; 2920 int i; 2921 int num_unfilled_slots = unfilled_slots_next - unfilled_slots_base; 2922 2923 for (i = 0; i < num_unfilled_slots; i++) 2924 { 2925 rtx condition; 2926 rtx target_label, insn_at_target, fallthrough_insn; 2927 rtx delay_list = 0; 2928 int own_target; 2929 int own_fallthrough; 2930 int prediction, slots_to_fill, slots_filled; 2931 2932 insn = unfilled_slots_base[i]; 2933 if (insn == 0 2934 || INSN_DELETED_P (insn) 2935 || !JUMP_P (insn) 2936 || ! (condjump_p (insn) || condjump_in_parallel_p (insn))) 2937 continue; 2938 2939 slots_to_fill = num_delay_slots (insn); 2940 /* Some machine description have defined instructions to have 2941 delay slots only in certain circumstances which may depend on 2942 nearby insns (which change due to reorg's actions). 2943 2944 For example, the PA port normally has delay slots for unconditional 2945 jumps. 2946 2947 However, the PA port claims such jumps do not have a delay slot 2948 if they are immediate successors of certain CALL_INSNs. This 2949 allows the port to favor filling the delay slot of the call with 2950 the unconditional jump. */ 2951 if (slots_to_fill == 0) 2952 continue; 2953 2954 slots_filled = 0; 2955 target_label = JUMP_LABEL (insn); 2956 condition = get_branch_condition (insn, target_label); 2957 2958 if (condition == 0) 2959 continue; 2960 2961 /* Get the next active fallthrough and target insns and see if we own 2962 them. Then see whether the branch is likely true. We don't need 2963 to do a lot of this for unconditional branches. */ 2964 2965 insn_at_target = next_active_insn (target_label); 2966 own_target = own_thread_p (target_label, target_label, 0); 2967 2968 if (condition == const_true_rtx) 2969 { 2970 own_fallthrough = 0; 2971 fallthrough_insn = 0; 2972 prediction = 2; 2973 } 2974 else 2975 { 2976 fallthrough_insn = next_active_insn (insn); 2977 own_fallthrough = own_thread_p (NEXT_INSN (insn), NULL_RTX, 1); 2978 prediction = mostly_true_jump (insn, condition); 2979 } 2980 2981 /* If this insn is expected to branch, first try to get insns from our 2982 target, then our fallthrough insns. If it is not expected to branch, 2983 try the other order. */ 2984 2985 if (prediction > 0) 2986 { 2987 delay_list 2988 = fill_slots_from_thread (insn, condition, insn_at_target, 2989 fallthrough_insn, prediction == 2, 1, 2990 own_target, 2991 slots_to_fill, &slots_filled, delay_list); 2992 2993 if (delay_list == 0 && own_fallthrough) 2994 { 2995 /* Even though we didn't find anything for delay slots, 2996 we might have found a redundant insn which we deleted 2997 from the thread that was filled. So we have to recompute 2998 the next insn at the target. */ 2999 target_label = JUMP_LABEL (insn); 3000 insn_at_target = next_active_insn (target_label); 3001 3002 delay_list 3003 = fill_slots_from_thread (insn, condition, fallthrough_insn, 3004 insn_at_target, 0, 0, 3005 own_fallthrough, 3006 slots_to_fill, &slots_filled, 3007 delay_list); 3008 } 3009 } 3010 else 3011 { 3012 if (own_fallthrough) 3013 delay_list 3014 = fill_slots_from_thread (insn, condition, fallthrough_insn, 3015 insn_at_target, 0, 0, 3016 own_fallthrough, 3017 slots_to_fill, &slots_filled, 3018 delay_list); 3019 3020 if (delay_list == 0) 3021 delay_list 3022 = fill_slots_from_thread (insn, condition, insn_at_target, 3023 next_active_insn (insn), 0, 1, 3024 own_target, 3025 slots_to_fill, &slots_filled, 3026 delay_list); 3027 } 3028 3029 if (delay_list) 3030 unfilled_slots_base[i] 3031 = emit_delay_sequence (insn, delay_list, slots_filled); 3032 3033 if (slots_to_fill == slots_filled) 3034 unfilled_slots_base[i] = 0; 3035 3036 note_delay_statistics (slots_filled, 1); 3037 } 3038} 3039 3040/* Once we have tried two ways to fill a delay slot, make a pass over the 3041 code to try to improve the results and to do such things as more jump 3042 threading. */ 3043 3044static void 3045relax_delay_slots (rtx first) 3046{ 3047 rtx insn, next, pat; 3048 rtx trial, delay_insn, target_label; 3049 3050 /* Look at every JUMP_INSN and see if we can improve it. */ 3051 for (insn = first; insn; insn = next) 3052 { 3053 rtx other; 3054 3055 next = next_active_insn (insn); 3056 3057 /* If this is a jump insn, see if it now jumps to a jump, jumps to 3058 the next insn, or jumps to a label that is not the last of a 3059 group of consecutive labels. */ 3060 if (JUMP_P (insn) 3061 && (condjump_p (insn) || condjump_in_parallel_p (insn)) 3062 && (target_label = JUMP_LABEL (insn)) != 0) 3063 { 3064 target_label = skip_consecutive_labels (follow_jumps (target_label)); 3065 if (target_label == 0) 3066 target_label = find_end_label (); 3067 3068 if (target_label && next_active_insn (target_label) == next 3069 && ! condjump_in_parallel_p (insn)) 3070 { 3071 delete_jump (insn); 3072 continue; 3073 } 3074 3075 if (target_label && target_label != JUMP_LABEL (insn)) 3076 reorg_redirect_jump (insn, target_label); 3077 3078 /* See if this jump conditionally branches around an unconditional 3079 jump. If so, invert this jump and point it to the target of the 3080 second jump. */ 3081 if (next && JUMP_P (next) 3082 && any_condjump_p (insn) 3083 && (simplejump_p (next) || GET_CODE (PATTERN (next)) == RETURN) 3084 && target_label 3085 && next_active_insn (target_label) == next_active_insn (next) 3086 && no_labels_between_p (insn, next)) 3087 { 3088 rtx label = JUMP_LABEL (next); 3089 3090 /* Be careful how we do this to avoid deleting code or 3091 labels that are momentarily dead. See similar optimization 3092 in jump.c. 3093 3094 We also need to ensure we properly handle the case when 3095 invert_jump fails. */ 3096 3097 ++LABEL_NUSES (target_label); 3098 if (label) 3099 ++LABEL_NUSES (label); 3100 3101 if (invert_jump (insn, label, 1)) 3102 { 3103 delete_related_insns (next); 3104 next = insn; 3105 } 3106 3107 if (label) 3108 --LABEL_NUSES (label); 3109 3110 if (--LABEL_NUSES (target_label) == 0) 3111 delete_related_insns (target_label); 3112 3113 continue; 3114 } 3115 } 3116 3117 /* If this is an unconditional jump and the previous insn is a 3118 conditional jump, try reversing the condition of the previous 3119 insn and swapping our targets. The next pass might be able to 3120 fill the slots. 3121 3122 Don't do this if we expect the conditional branch to be true, because 3123 we would then be making the more common case longer. */ 3124 3125 if (JUMP_P (insn) 3126 && (simplejump_p (insn) || GET_CODE (PATTERN (insn)) == RETURN) 3127 && (other = prev_active_insn (insn)) != 0 3128 && any_condjump_p (other) 3129 && no_labels_between_p (other, insn) 3130 && 0 > mostly_true_jump (other, 3131 get_branch_condition (other, 3132 JUMP_LABEL (other)))) 3133 { 3134 rtx other_target = JUMP_LABEL (other); 3135 target_label = JUMP_LABEL (insn); 3136 3137 if (invert_jump (other, target_label, 0)) 3138 reorg_redirect_jump (insn, other_target); 3139 } 3140 3141 /* Now look only at cases where we have filled a delay slot. */ 3142 if (!NONJUMP_INSN_P (insn) 3143 || GET_CODE (PATTERN (insn)) != SEQUENCE) 3144 continue; 3145 3146 pat = PATTERN (insn); 3147 delay_insn = XVECEXP (pat, 0, 0); 3148 3149 /* See if the first insn in the delay slot is redundant with some 3150 previous insn. Remove it from the delay slot if so; then set up 3151 to reprocess this insn. */ 3152 if (redundant_insn (XVECEXP (pat, 0, 1), delay_insn, 0)) 3153 { 3154 delete_from_delay_slot (XVECEXP (pat, 0, 1)); 3155 next = prev_active_insn (next); 3156 continue; 3157 } 3158 3159 /* See if we have a RETURN insn with a filled delay slot followed 3160 by a RETURN insn with an unfilled a delay slot. If so, we can delete 3161 the first RETURN (but not its delay insn). This gives the same 3162 effect in fewer instructions. 3163 3164 Only do so if optimizing for size since this results in slower, but 3165 smaller code. */ 3166 if (optimize_size 3167 && GET_CODE (PATTERN (delay_insn)) == RETURN 3168 && next 3169 && JUMP_P (next) 3170 && GET_CODE (PATTERN (next)) == RETURN) 3171 { 3172 rtx after; 3173 int i; 3174 3175 /* Delete the RETURN and just execute the delay list insns. 3176 3177 We do this by deleting the INSN containing the SEQUENCE, then 3178 re-emitting the insns separately, and then deleting the RETURN. 3179 This allows the count of the jump target to be properly 3180 decremented. */ 3181 3182 /* Clear the from target bit, since these insns are no longer 3183 in delay slots. */ 3184 for (i = 0; i < XVECLEN (pat, 0); i++) 3185 INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)) = 0; 3186 3187 trial = PREV_INSN (insn); 3188 delete_related_insns (insn); 3189 gcc_assert (GET_CODE (pat) == SEQUENCE); 3190 after = trial; 3191 for (i = 0; i < XVECLEN (pat, 0); i++) 3192 { 3193 rtx this_insn = XVECEXP (pat, 0, i); 3194 add_insn_after (this_insn, after); 3195 after = this_insn; 3196 } 3197 delete_scheduled_jump (delay_insn); 3198 continue; 3199 } 3200 3201 /* Now look only at the cases where we have a filled JUMP_INSN. */ 3202 if (!JUMP_P (XVECEXP (PATTERN (insn), 0, 0)) 3203 || ! (condjump_p (XVECEXP (PATTERN (insn), 0, 0)) 3204 || condjump_in_parallel_p (XVECEXP (PATTERN (insn), 0, 0)))) 3205 continue; 3206 3207 target_label = JUMP_LABEL (delay_insn); 3208 3209 if (target_label) 3210 { 3211 /* If this jump goes to another unconditional jump, thread it, but 3212 don't convert a jump into a RETURN here. */ 3213 trial = skip_consecutive_labels (follow_jumps (target_label)); 3214 if (trial == 0) 3215 trial = find_end_label (); 3216 3217 if (trial && trial != target_label 3218 && redirect_with_delay_slots_safe_p (delay_insn, trial, insn)) 3219 { 3220 reorg_redirect_jump (delay_insn, trial); 3221 target_label = trial; 3222 } 3223 3224 /* If the first insn at TARGET_LABEL is redundant with a previous 3225 insn, redirect the jump to the following insn process again. */ 3226 trial = next_active_insn (target_label); 3227 if (trial && GET_CODE (PATTERN (trial)) != SEQUENCE 3228 && redundant_insn (trial, insn, 0) 3229 && ! can_throw_internal (trial)) 3230 { 3231 /* Figure out where to emit the special USE insn so we don't 3232 later incorrectly compute register live/death info. */ 3233 rtx tmp = next_active_insn (trial); 3234 if (tmp == 0) 3235 tmp = find_end_label (); 3236 3237 if (tmp) 3238 { 3239 /* Insert the special USE insn and update dataflow info. */ 3240 update_block (trial, tmp); 3241 3242 /* Now emit a label before the special USE insn, and 3243 redirect our jump to the new label. */ 3244 target_label = get_label_before (PREV_INSN (tmp)); 3245 reorg_redirect_jump (delay_insn, target_label); 3246 next = insn; 3247 continue; 3248 } 3249 } 3250 3251 /* Similarly, if it is an unconditional jump with one insn in its 3252 delay list and that insn is redundant, thread the jump. */ 3253 if (trial && GET_CODE (PATTERN (trial)) == SEQUENCE 3254 && XVECLEN (PATTERN (trial), 0) == 2 3255 && JUMP_P (XVECEXP (PATTERN (trial), 0, 0)) 3256 && (simplejump_p (XVECEXP (PATTERN (trial), 0, 0)) 3257 || GET_CODE (PATTERN (XVECEXP (PATTERN (trial), 0, 0))) == RETURN) 3258 && redundant_insn (XVECEXP (PATTERN (trial), 0, 1), insn, 0)) 3259 { 3260 target_label = JUMP_LABEL (XVECEXP (PATTERN (trial), 0, 0)); 3261 if (target_label == 0) 3262 target_label = find_end_label (); 3263 3264 if (target_label 3265 && redirect_with_delay_slots_safe_p (delay_insn, target_label, 3266 insn)) 3267 { 3268 reorg_redirect_jump (delay_insn, target_label); 3269 next = insn; 3270 continue; 3271 } 3272 } 3273 } 3274 3275 if (! INSN_ANNULLED_BRANCH_P (delay_insn) 3276 && prev_active_insn (target_label) == insn 3277 && ! condjump_in_parallel_p (delay_insn) 3278#ifdef HAVE_cc0 3279 /* If the last insn in the delay slot sets CC0 for some insn, 3280 various code assumes that it is in a delay slot. We could 3281 put it back where it belonged and delete the register notes, 3282 but it doesn't seem worthwhile in this uncommon case. */ 3283 && ! find_reg_note (XVECEXP (pat, 0, XVECLEN (pat, 0) - 1), 3284 REG_CC_USER, NULL_RTX) 3285#endif 3286 ) 3287 { 3288 rtx after; 3289 int i; 3290 3291 /* All this insn does is execute its delay list and jump to the 3292 following insn. So delete the jump and just execute the delay 3293 list insns. 3294 3295 We do this by deleting the INSN containing the SEQUENCE, then 3296 re-emitting the insns separately, and then deleting the jump. 3297 This allows the count of the jump target to be properly 3298 decremented. */ 3299 3300 /* Clear the from target bit, since these insns are no longer 3301 in delay slots. */ 3302 for (i = 0; i < XVECLEN (pat, 0); i++) 3303 INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)) = 0; 3304 3305 trial = PREV_INSN (insn); 3306 delete_related_insns (insn); 3307 gcc_assert (GET_CODE (pat) == SEQUENCE); 3308 after = trial; 3309 for (i = 0; i < XVECLEN (pat, 0); i++) 3310 { 3311 rtx this_insn = XVECEXP (pat, 0, i); 3312 add_insn_after (this_insn, after); 3313 after = this_insn; 3314 } 3315 delete_scheduled_jump (delay_insn); 3316 continue; 3317 } 3318 3319 /* See if this is an unconditional jump around a single insn which is 3320 identical to the one in its delay slot. In this case, we can just 3321 delete the branch and the insn in its delay slot. */ 3322 if (next && NONJUMP_INSN_P (next) 3323 && prev_label (next_active_insn (next)) == target_label 3324 && simplejump_p (insn) 3325 && XVECLEN (pat, 0) == 2 3326 && rtx_equal_p (PATTERN (next), PATTERN (XVECEXP (pat, 0, 1)))) 3327 { 3328 delete_related_insns (insn); 3329 continue; 3330 } 3331 3332 /* See if this jump (with its delay slots) conditionally branches 3333 around an unconditional jump (without delay slots). If so, invert 3334 this jump and point it to the target of the second jump. We cannot 3335 do this for annulled jumps, though. Again, don't convert a jump to 3336 a RETURN here. */ 3337 if (! INSN_ANNULLED_BRANCH_P (delay_insn) 3338 && any_condjump_p (delay_insn) 3339 && next && JUMP_P (next) 3340 && (simplejump_p (next) || GET_CODE (PATTERN (next)) == RETURN) 3341 && next_active_insn (target_label) == next_active_insn (next) 3342 && no_labels_between_p (insn, next)) 3343 { 3344 rtx label = JUMP_LABEL (next); 3345 rtx old_label = JUMP_LABEL (delay_insn); 3346 3347 if (label == 0) 3348 label = find_end_label (); 3349 3350 /* find_end_label can generate a new label. Check this first. */ 3351 if (label 3352 && no_labels_between_p (insn, next) 3353 && redirect_with_delay_slots_safe_p (delay_insn, label, insn)) 3354 { 3355 /* Be careful how we do this to avoid deleting code or labels 3356 that are momentarily dead. See similar optimization in 3357 jump.c */ 3358 if (old_label) 3359 ++LABEL_NUSES (old_label); 3360 3361 if (invert_jump (delay_insn, label, 1)) 3362 { 3363 int i; 3364 3365 /* Must update the INSN_FROM_TARGET_P bits now that 3366 the branch is reversed, so that mark_target_live_regs 3367 will handle the delay slot insn correctly. */ 3368 for (i = 1; i < XVECLEN (PATTERN (insn), 0); i++) 3369 { 3370 rtx slot = XVECEXP (PATTERN (insn), 0, i); 3371 INSN_FROM_TARGET_P (slot) = ! INSN_FROM_TARGET_P (slot); 3372 } 3373 3374 delete_related_insns (next); 3375 next = insn; 3376 } 3377 3378 if (old_label && --LABEL_NUSES (old_label) == 0) 3379 delete_related_insns (old_label); 3380 continue; 3381 } 3382 } 3383 3384 /* If we own the thread opposite the way this insn branches, see if we 3385 can merge its delay slots with following insns. */ 3386 if (INSN_FROM_TARGET_P (XVECEXP (pat, 0, 1)) 3387 && own_thread_p (NEXT_INSN (insn), 0, 1)) 3388 try_merge_delay_insns (insn, next); 3389 else if (! INSN_FROM_TARGET_P (XVECEXP (pat, 0, 1)) 3390 && own_thread_p (target_label, target_label, 0)) 3391 try_merge_delay_insns (insn, next_active_insn (target_label)); 3392 3393 /* If we get here, we haven't deleted INSN. But we may have deleted 3394 NEXT, so recompute it. */ 3395 next = next_active_insn (insn); 3396 } 3397} 3398 3399#ifdef HAVE_return 3400 3401/* Look for filled jumps to the end of function label. We can try to convert 3402 them into RETURN insns if the insns in the delay slot are valid for the 3403 RETURN as well. */ 3404 3405static void 3406make_return_insns (rtx first) 3407{ 3408 rtx insn, jump_insn, pat; 3409 rtx real_return_label = end_of_function_label; 3410 int slots, i; 3411 3412#ifdef DELAY_SLOTS_FOR_EPILOGUE 3413 /* If a previous pass filled delay slots in the epilogue, things get a 3414 bit more complicated, as those filler insns would generally (without 3415 data flow analysis) have to be executed after any existing branch 3416 delay slot filler insns. It is also unknown whether such a 3417 transformation would actually be profitable. Note that the existing 3418 code only cares for branches with (some) filled delay slots. */ 3419 if (current_function_epilogue_delay_list != NULL) 3420 return; 3421#endif 3422 3423 /* See if there is a RETURN insn in the function other than the one we 3424 made for END_OF_FUNCTION_LABEL. If so, set up anything we can't change 3425 into a RETURN to jump to it. */ 3426 for (insn = first; insn; insn = NEXT_INSN (insn)) 3427 if (JUMP_P (insn) && GET_CODE (PATTERN (insn)) == RETURN) 3428 { 3429 real_return_label = get_label_before (insn); 3430 break; 3431 } 3432 3433 /* Show an extra usage of REAL_RETURN_LABEL so it won't go away if it 3434 was equal to END_OF_FUNCTION_LABEL. */ 3435 LABEL_NUSES (real_return_label)++; 3436 3437 /* Clear the list of insns to fill so we can use it. */ 3438 obstack_free (&unfilled_slots_obstack, unfilled_firstobj); 3439 3440 for (insn = first; insn; insn = NEXT_INSN (insn)) 3441 { 3442 int flags; 3443 3444 /* Only look at filled JUMP_INSNs that go to the end of function 3445 label. */ 3446 if (!NONJUMP_INSN_P (insn) 3447 || GET_CODE (PATTERN (insn)) != SEQUENCE 3448 || !JUMP_P (XVECEXP (PATTERN (insn), 0, 0)) 3449 || JUMP_LABEL (XVECEXP (PATTERN (insn), 0, 0)) != end_of_function_label) 3450 continue; 3451 3452 pat = PATTERN (insn); 3453 jump_insn = XVECEXP (pat, 0, 0); 3454 3455 /* If we can't make the jump into a RETURN, try to redirect it to the best 3456 RETURN and go on to the next insn. */ 3457 if (! reorg_redirect_jump (jump_insn, NULL_RTX)) 3458 { 3459 /* Make sure redirecting the jump will not invalidate the delay 3460 slot insns. */ 3461 if (redirect_with_delay_slots_safe_p (jump_insn, 3462 real_return_label, 3463 insn)) 3464 reorg_redirect_jump (jump_insn, real_return_label); 3465 continue; 3466 } 3467 3468 /* See if this RETURN can accept the insns current in its delay slot. 3469 It can if it has more or an equal number of slots and the contents 3470 of each is valid. */ 3471 3472 flags = get_jump_flags (jump_insn, JUMP_LABEL (jump_insn)); 3473 slots = num_delay_slots (jump_insn); 3474 if (slots >= XVECLEN (pat, 0) - 1) 3475 { 3476 for (i = 1; i < XVECLEN (pat, 0); i++) 3477 if (! ( 3478#ifdef ANNUL_IFFALSE_SLOTS 3479 (INSN_ANNULLED_BRANCH_P (jump_insn) 3480 && INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) 3481 ? eligible_for_annul_false (jump_insn, i - 1, 3482 XVECEXP (pat, 0, i), flags) : 3483#endif 3484#ifdef ANNUL_IFTRUE_SLOTS 3485 (INSN_ANNULLED_BRANCH_P (jump_insn) 3486 && ! INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) 3487 ? eligible_for_annul_true (jump_insn, i - 1, 3488 XVECEXP (pat, 0, i), flags) : 3489#endif 3490 eligible_for_delay (jump_insn, i - 1, 3491 XVECEXP (pat, 0, i), flags))) 3492 break; 3493 } 3494 else 3495 i = 0; 3496 3497 if (i == XVECLEN (pat, 0)) 3498 continue; 3499 3500 /* We have to do something with this insn. If it is an unconditional 3501 RETURN, delete the SEQUENCE and output the individual insns, 3502 followed by the RETURN. Then set things up so we try to find 3503 insns for its delay slots, if it needs some. */ 3504 if (GET_CODE (PATTERN (jump_insn)) == RETURN) 3505 { 3506 rtx prev = PREV_INSN (insn); 3507 3508 delete_related_insns (insn); 3509 for (i = 1; i < XVECLEN (pat, 0); i++) 3510 prev = emit_insn_after (PATTERN (XVECEXP (pat, 0, i)), prev); 3511 3512 insn = emit_jump_insn_after (PATTERN (jump_insn), prev); 3513 emit_barrier_after (insn); 3514 3515 if (slots) 3516 obstack_ptr_grow (&unfilled_slots_obstack, insn); 3517 } 3518 else 3519 /* It is probably more efficient to keep this with its current 3520 delay slot as a branch to a RETURN. */ 3521 reorg_redirect_jump (jump_insn, real_return_label); 3522 } 3523 3524 /* Now delete REAL_RETURN_LABEL if we never used it. Then try to fill any 3525 new delay slots we have created. */ 3526 if (--LABEL_NUSES (real_return_label) == 0) 3527 delete_related_insns (real_return_label); 3528 3529 fill_simple_delay_slots (1); 3530 fill_simple_delay_slots (0); 3531} 3532#endif 3533 3534/* Try to find insns to place in delay slots. */ 3535 3536void 3537dbr_schedule (rtx first) 3538{ 3539 rtx insn, next, epilogue_insn = 0; 3540 int i; 3541 3542 /* If the current function has no insns other than the prologue and 3543 epilogue, then do not try to fill any delay slots. */ 3544 if (n_basic_blocks == NUM_FIXED_BLOCKS) 3545 return; 3546 3547 /* Find the highest INSN_UID and allocate and initialize our map from 3548 INSN_UID's to position in code. */ 3549 for (max_uid = 0, insn = first; insn; insn = NEXT_INSN (insn)) 3550 { 3551 if (INSN_UID (insn) > max_uid) 3552 max_uid = INSN_UID (insn); 3553 if (NOTE_P (insn) 3554 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EPILOGUE_BEG) 3555 epilogue_insn = insn; 3556 } 3557 3558 uid_to_ruid = xmalloc ((max_uid + 1) * sizeof (int)); 3559 for (i = 0, insn = first; insn; i++, insn = NEXT_INSN (insn)) 3560 uid_to_ruid[INSN_UID (insn)] = i; 3561 3562 /* Initialize the list of insns that need filling. */ 3563 if (unfilled_firstobj == 0) 3564 { 3565 gcc_obstack_init (&unfilled_slots_obstack); 3566 unfilled_firstobj = obstack_alloc (&unfilled_slots_obstack, 0); 3567 } 3568 3569 for (insn = next_active_insn (first); insn; insn = next_active_insn (insn)) 3570 { 3571 rtx target; 3572 3573 INSN_ANNULLED_BRANCH_P (insn) = 0; 3574 INSN_FROM_TARGET_P (insn) = 0; 3575 3576 /* Skip vector tables. We can't get attributes for them. */ 3577 if (JUMP_P (insn) 3578 && (GET_CODE (PATTERN (insn)) == ADDR_VEC 3579 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)) 3580 continue; 3581 3582 if (num_delay_slots (insn) > 0) 3583 obstack_ptr_grow (&unfilled_slots_obstack, insn); 3584 3585 /* Ensure all jumps go to the last of a set of consecutive labels. */ 3586 if (JUMP_P (insn) 3587 && (condjump_p (insn) || condjump_in_parallel_p (insn)) 3588 && JUMP_LABEL (insn) != 0 3589 && ((target = skip_consecutive_labels (JUMP_LABEL (insn))) 3590 != JUMP_LABEL (insn))) 3591 redirect_jump (insn, target, 1); 3592 } 3593 3594 init_resource_info (epilogue_insn); 3595 3596 /* Show we haven't computed an end-of-function label yet. */ 3597 end_of_function_label = 0; 3598 3599 /* Initialize the statistics for this function. */ 3600 memset (num_insns_needing_delays, 0, sizeof num_insns_needing_delays); 3601 memset (num_filled_delays, 0, sizeof num_filled_delays); 3602 3603 /* Now do the delay slot filling. Try everything twice in case earlier 3604 changes make more slots fillable. */ 3605 3606 for (reorg_pass_number = 0; 3607 reorg_pass_number < MAX_REORG_PASSES; 3608 reorg_pass_number++) 3609 { 3610 fill_simple_delay_slots (1); 3611 fill_simple_delay_slots (0); 3612 fill_eager_delay_slots (); 3613 relax_delay_slots (first); 3614 } 3615 3616 /* Delete any USE insns made by update_block; subsequent passes don't need 3617 them or know how to deal with them. */ 3618 for (insn = first; insn; insn = next) 3619 { 3620 next = NEXT_INSN (insn); 3621 3622 if (NONJUMP_INSN_P (insn) && GET_CODE (PATTERN (insn)) == USE 3623 && INSN_P (XEXP (PATTERN (insn), 0))) 3624 next = delete_related_insns (insn); 3625 } 3626 3627 /* If we made an end of function label, indicate that it is now 3628 safe to delete it by undoing our prior adjustment to LABEL_NUSES. 3629 If it is now unused, delete it. */ 3630 if (end_of_function_label && --LABEL_NUSES (end_of_function_label) == 0) 3631 delete_related_insns (end_of_function_label); 3632 3633#ifdef HAVE_return 3634 if (HAVE_return && end_of_function_label != 0) 3635 make_return_insns (first); 3636#endif 3637 3638 obstack_free (&unfilled_slots_obstack, unfilled_firstobj); 3639 3640 /* It is not clear why the line below is needed, but it does seem to be. */ 3641 unfilled_firstobj = obstack_alloc (&unfilled_slots_obstack, 0); 3642 3643 if (dump_file) 3644 { 3645 int i, j, need_comma; 3646 int total_delay_slots[MAX_DELAY_HISTOGRAM + 1]; 3647 int total_annul_slots[MAX_DELAY_HISTOGRAM + 1]; 3648 3649 for (reorg_pass_number = 0; 3650 reorg_pass_number < MAX_REORG_PASSES; 3651 reorg_pass_number++) 3652 { 3653 fprintf (dump_file, ";; Reorg pass #%d:\n", reorg_pass_number + 1); 3654 for (i = 0; i < NUM_REORG_FUNCTIONS; i++) 3655 { 3656 need_comma = 0; 3657 fprintf (dump_file, ";; Reorg function #%d\n", i); 3658 3659 fprintf (dump_file, ";; %d insns needing delay slots\n;; ", 3660 num_insns_needing_delays[i][reorg_pass_number]); 3661 3662 for (j = 0; j < MAX_DELAY_HISTOGRAM + 1; j++) 3663 if (num_filled_delays[i][j][reorg_pass_number]) 3664 { 3665 if (need_comma) 3666 fprintf (dump_file, ", "); 3667 need_comma = 1; 3668 fprintf (dump_file, "%d got %d delays", 3669 num_filled_delays[i][j][reorg_pass_number], j); 3670 } 3671 fprintf (dump_file, "\n"); 3672 } 3673 } 3674 memset (total_delay_slots, 0, sizeof total_delay_slots); 3675 memset (total_annul_slots, 0, sizeof total_annul_slots); 3676 for (insn = first; insn; insn = NEXT_INSN (insn)) 3677 { 3678 if (! INSN_DELETED_P (insn) 3679 && NONJUMP_INSN_P (insn) 3680 && GET_CODE (PATTERN (insn)) != USE 3681 && GET_CODE (PATTERN (insn)) != CLOBBER) 3682 { 3683 if (GET_CODE (PATTERN (insn)) == SEQUENCE) 3684 { 3685 j = XVECLEN (PATTERN (insn), 0) - 1; 3686 if (j > MAX_DELAY_HISTOGRAM) 3687 j = MAX_DELAY_HISTOGRAM; 3688 if (INSN_ANNULLED_BRANCH_P (XVECEXP (PATTERN (insn), 0, 0))) 3689 total_annul_slots[j]++; 3690 else 3691 total_delay_slots[j]++; 3692 } 3693 else if (num_delay_slots (insn) > 0) 3694 total_delay_slots[0]++; 3695 } 3696 } 3697 fprintf (dump_file, ";; Reorg totals: "); 3698 need_comma = 0; 3699 for (j = 0; j < MAX_DELAY_HISTOGRAM + 1; j++) 3700 { 3701 if (total_delay_slots[j]) 3702 { 3703 if (need_comma) 3704 fprintf (dump_file, ", "); 3705 need_comma = 1; 3706 fprintf (dump_file, "%d got %d delays", total_delay_slots[j], j); 3707 } 3708 } 3709 fprintf (dump_file, "\n"); 3710#if defined (ANNUL_IFTRUE_SLOTS) || defined (ANNUL_IFFALSE_SLOTS) 3711 fprintf (dump_file, ";; Reorg annuls: "); 3712 need_comma = 0; 3713 for (j = 0; j < MAX_DELAY_HISTOGRAM + 1; j++) 3714 { 3715 if (total_annul_slots[j]) 3716 { 3717 if (need_comma) 3718 fprintf (dump_file, ", "); 3719 need_comma = 1; 3720 fprintf (dump_file, "%d got %d delays", total_annul_slots[j], j); 3721 } 3722 } 3723 fprintf (dump_file, "\n"); 3724#endif 3725 fprintf (dump_file, "\n"); 3726 } 3727 3728 /* For all JUMP insns, fill in branch prediction notes, so that during 3729 assembler output a target can set branch prediction bits in the code. 3730 We have to do this now, as up until this point the destinations of 3731 JUMPS can be moved around and changed, but past right here that cannot 3732 happen. */ 3733 for (insn = first; insn; insn = NEXT_INSN (insn)) 3734 { 3735 int pred_flags; 3736 3737 if (NONJUMP_INSN_P (insn)) 3738 { 3739 rtx pat = PATTERN (insn); 3740 3741 if (GET_CODE (pat) == SEQUENCE) 3742 insn = XVECEXP (pat, 0, 0); 3743 } 3744 if (!JUMP_P (insn)) 3745 continue; 3746 3747 pred_flags = get_jump_flags (insn, JUMP_LABEL (insn)); 3748 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_BR_PRED, 3749 GEN_INT (pred_flags), 3750 REG_NOTES (insn)); 3751 } 3752 free_resource_info (); 3753 free (uid_to_ruid); 3754#ifdef DELAY_SLOTS_FOR_EPILOGUE 3755 /* SPARC assembler, for instance, emit warning when debug info is output 3756 into the delay slot. */ 3757 { 3758 rtx link; 3759 3760 for (link = current_function_epilogue_delay_list; 3761 link; 3762 link = XEXP (link, 1)) 3763 INSN_LOCATOR (XEXP (link, 0)) = 0; 3764 } 3765#endif 3766} 3767#endif /* DELAY_SLOTS */ 3768 3769static bool 3770gate_handle_delay_slots (void) 3771{ 3772#ifdef DELAY_SLOTS 3773 return flag_delayed_branch; 3774#else 3775 return 0; 3776#endif 3777} 3778 3779/* Run delay slot optimization. */ 3780static unsigned int 3781rest_of_handle_delay_slots (void) 3782{ 3783#ifdef DELAY_SLOTS 3784 dbr_schedule (get_insns ()); 3785#endif 3786 return 0; 3787} 3788 3789struct tree_opt_pass pass_delay_slots = 3790{ 3791 "dbr", /* name */ 3792 gate_handle_delay_slots, /* gate */ 3793 rest_of_handle_delay_slots, /* execute */ 3794 NULL, /* sub */ 3795 NULL, /* next */ 3796 0, /* static_pass_number */ 3797 TV_DBR_SCHED, /* tv_id */ 3798 0, /* properties_required */ 3799 0, /* properties_provided */ 3800 0, /* properties_destroyed */ 3801 0, /* todo_flags_start */ 3802 TODO_dump_func | 3803 TODO_ggc_collect, /* todo_flags_finish */ 3804 'd' /* letter */ 3805}; 3806 3807/* Machine dependent reorg pass. */ 3808static bool 3809gate_handle_machine_reorg (void) 3810{ 3811 return targetm.machine_dependent_reorg != 0; 3812} 3813 3814 3815static unsigned int 3816rest_of_handle_machine_reorg (void) 3817{ 3818 targetm.machine_dependent_reorg (); 3819 return 0; 3820} 3821 3822struct tree_opt_pass pass_machine_reorg = 3823{ 3824 "mach", /* name */ 3825 gate_handle_machine_reorg, /* gate */ 3826 rest_of_handle_machine_reorg, /* execute */ 3827 NULL, /* sub */ 3828 NULL, /* next */ 3829 0, /* static_pass_number */ 3830 TV_MACH_DEP, /* tv_id */ 3831 0, /* properties_required */ 3832 0, /* properties_provided */ 3833 0, /* properties_destroyed */ 3834 0, /* todo_flags_start */ 3835 TODO_dump_func | 3836 TODO_ggc_collect, /* todo_flags_finish */ 3837 'M' /* letter */ 3838}; 3839 3840