Daily bump.
[official-gcc.git] / gcc / sched-ebb.c
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1 /* Instruction scheduling pass.
2 Copyright (C) 1992-2015 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com) Enhanced by,
4 and currently maintained by, Jim Wilson (wilson@cygnus.com)
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 #include "config.h"
23 #include "system.h"
24 #include "coretypes.h"
25 #include "tm.h"
26 #include "diagnostic-core.h"
27 #include "rtl.h"
28 #include "tm_p.h"
29 #include "hard-reg-set.h"
30 #include "regs.h"
31 #include "hashtab.h"
32 #include "hash-set.h"
33 #include "vec.h"
34 #include "machmode.h"
35 #include "input.h"
36 #include "function.h"
37 #include "profile.h"
38 #include "flags.h"
39 #include "insn-config.h"
40 #include "insn-attr.h"
41 #include "except.h"
42 #include "recog.h"
43 #include "params.h"
44 #include "dominance.h"
45 #include "cfg.h"
46 #include "cfgrtl.h"
47 #include "cfgbuild.h"
48 #include "predict.h"
49 #include "basic-block.h"
50 #include "sched-int.h"
51 #include "target.h"
54 #ifdef INSN_SCHEDULING
56 /* The number of insns to be scheduled in total. */
57 static int rgn_n_insns;
59 /* The number of insns scheduled so far. */
60 static int sched_rgn_n_insns;
62 /* Set of blocks, that already have their dependencies calculated. */
63 static bitmap_head dont_calc_deps;
65 /* Last basic block in current ebb. */
66 static basic_block last_bb;
68 /* Implementations of the sched_info functions for region scheduling. */
69 static void init_ready_list (void);
70 static void begin_schedule_ready (rtx_insn *);
71 static int schedule_more_p (void);
72 static const char *ebb_print_insn (const rtx_insn *, int);
73 static int rank (rtx_insn *, rtx_insn *);
74 static int ebb_contributes_to_priority (rtx_insn *, rtx_insn *);
75 static basic_block earliest_block_with_similiar_load (basic_block, rtx);
76 static void add_deps_for_risky_insns (rtx_insn *, rtx_insn *);
77 static void debug_ebb_dependencies (rtx_insn *, rtx_insn *);
79 static void ebb_add_remove_insn (rtx_insn *, int);
80 static void ebb_add_block (basic_block, basic_block);
81 static basic_block advance_target_bb (basic_block, rtx_insn *);
82 static void ebb_fix_recovery_cfg (int, int, int);
84 /* Allocate memory and store the state of the frontend. Return the allocated
85 memory. */
86 static void *
87 save_ebb_state (void)
89 int *p = XNEW (int);
90 *p = sched_rgn_n_insns;
91 return p;
94 /* Restore the state of the frontend from P_, then free it. */
95 static void
96 restore_ebb_state (void *p_)
98 int *p = (int *)p_;
99 sched_rgn_n_insns = *p;
100 free (p_);
103 /* Return nonzero if there are more insns that should be scheduled. */
105 static int
106 schedule_more_p (void)
108 return sched_rgn_n_insns < rgn_n_insns;
111 /* Print dependency information about ebb between HEAD and TAIL. */
112 static void
113 debug_ebb_dependencies (rtx_insn *head, rtx_insn *tail)
115 fprintf (sched_dump,
116 ";; --------------- forward dependences: ------------ \n");
118 fprintf (sched_dump, "\n;; --- EBB Dependences --- from bb%d to bb%d \n",
119 BLOCK_NUM (head), BLOCK_NUM (tail));
121 debug_dependencies (head, tail);
124 /* Add all insns that are initially ready to the ready list READY. Called
125 once before scheduling a set of insns. */
127 static void
128 init_ready_list (void)
130 int n = 0;
131 rtx_insn *prev_head = current_sched_info->prev_head;
132 rtx_insn *next_tail = current_sched_info->next_tail;
133 rtx_insn *insn;
135 sched_rgn_n_insns = 0;
137 /* Print debugging information. */
138 if (sched_verbose >= 5)
139 debug_ebb_dependencies (NEXT_INSN (prev_head), PREV_INSN (next_tail));
141 /* Initialize ready list with all 'ready' insns in target block.
142 Count number of insns in the target block being scheduled. */
143 for (insn = NEXT_INSN (prev_head); insn != next_tail; insn = NEXT_INSN (insn))
145 try_ready (insn);
146 n++;
149 gcc_assert (n == rgn_n_insns);
152 /* INSN is being scheduled after LAST. Update counters. */
153 static void
154 begin_schedule_ready (rtx_insn *insn ATTRIBUTE_UNUSED)
156 sched_rgn_n_insns++;
159 /* INSN is being moved to its place in the schedule, after LAST. */
160 static void
161 begin_move_insn (rtx_insn *insn, rtx_insn *last)
163 if (BLOCK_FOR_INSN (insn) == last_bb
164 /* INSN is a jump in the last block, ... */
165 && control_flow_insn_p (insn)
166 /* that is going to be moved over some instructions. */
167 && last != PREV_INSN (insn))
169 edge e;
170 basic_block bb;
172 /* An obscure special case, where we do have partially dead
173 instruction scheduled after last control flow instruction.
174 In this case we can create new basic block. It is
175 always exactly one basic block last in the sequence. */
177 e = find_fallthru_edge (last_bb->succs);
179 gcc_checking_assert (!e || !(e->flags & EDGE_COMPLEX));
181 gcc_checking_assert (BLOCK_FOR_INSN (insn) == last_bb
182 && !IS_SPECULATION_CHECK_P (insn)
183 && BB_HEAD (last_bb) != insn
184 && BB_END (last_bb) == insn);
187 rtx x;
189 x = NEXT_INSN (insn);
190 if (e)
191 gcc_checking_assert (NOTE_P (x) || LABEL_P (x));
192 else
193 gcc_checking_assert (BARRIER_P (x));
196 if (e)
198 bb = split_edge (e);
199 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (BB_END (bb)));
201 else
203 /* Create an empty unreachable block after the INSN. */
204 rtx_insn *next = NEXT_INSN (insn);
205 if (next && BARRIER_P (next))
206 next = NEXT_INSN (next);
207 bb = create_basic_block (next, NULL_RTX, last_bb);
210 /* split_edge () creates BB before E->DEST. Keep in mind, that
211 this operation extends scheduling region till the end of BB.
212 Hence, we need to shift NEXT_TAIL, so haifa-sched.c won't go out
213 of the scheduling region. */
214 current_sched_info->next_tail = NEXT_INSN (BB_END (bb));
215 gcc_assert (current_sched_info->next_tail);
217 /* Append new basic block to the end of the ebb. */
218 sched_init_only_bb (bb, last_bb);
219 gcc_assert (last_bb == bb);
223 /* Return a string that contains the insn uid and optionally anything else
224 necessary to identify this insn in an output. It's valid to use a
225 static buffer for this. The ALIGNED parameter should cause the string
226 to be formatted so that multiple output lines will line up nicely. */
228 static const char *
229 ebb_print_insn (const rtx_insn *insn, int aligned ATTRIBUTE_UNUSED)
231 static char tmp[80];
233 /* '+' before insn means it is a new cycle start. */
234 if (GET_MODE (insn) == TImode)
235 sprintf (tmp, "+ %4d", INSN_UID (insn));
236 else
237 sprintf (tmp, " %4d", INSN_UID (insn));
239 return tmp;
242 /* Compare priority of two insns. Return a positive number if the second
243 insn is to be preferred for scheduling, and a negative one if the first
244 is to be preferred. Zero if they are equally good. */
246 static int
247 rank (rtx_insn *insn1, rtx_insn *insn2)
249 basic_block bb1 = BLOCK_FOR_INSN (insn1);
250 basic_block bb2 = BLOCK_FOR_INSN (insn2);
252 if (bb1->count > bb2->count
253 || bb1->frequency > bb2->frequency)
254 return -1;
255 if (bb1->count < bb2->count
256 || bb1->frequency < bb2->frequency)
257 return 1;
258 return 0;
261 /* NEXT is an instruction that depends on INSN (a backward dependence);
262 return nonzero if we should include this dependence in priority
263 calculations. */
265 static int
266 ebb_contributes_to_priority (rtx_insn *next ATTRIBUTE_UNUSED,
267 rtx_insn *insn ATTRIBUTE_UNUSED)
269 return 1;
272 /* INSN is a JUMP_INSN. Store the set of registers that
273 must be considered as used by this jump in USED. */
275 void
276 ebb_compute_jump_reg_dependencies (rtx insn, regset used)
278 basic_block b = BLOCK_FOR_INSN (insn);
279 edge e;
280 edge_iterator ei;
282 FOR_EACH_EDGE (e, ei, b->succs)
283 if ((e->flags & EDGE_FALLTHRU) == 0)
284 bitmap_ior_into (used, df_get_live_in (e->dest));
287 /* Used in schedule_insns to initialize current_sched_info for scheduling
288 regions (or single basic blocks). */
290 static struct common_sched_info_def ebb_common_sched_info;
292 static struct sched_deps_info_def ebb_sched_deps_info =
294 ebb_compute_jump_reg_dependencies,
295 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
296 NULL,
297 1, 0, 0
300 static struct haifa_sched_info ebb_sched_info =
302 init_ready_list,
303 NULL,
304 schedule_more_p,
305 NULL,
306 rank,
307 ebb_print_insn,
308 ebb_contributes_to_priority,
309 NULL, /* insn_finishes_block_p */
311 NULL, NULL,
312 NULL, NULL,
313 1, 0,
315 ebb_add_remove_insn,
316 begin_schedule_ready,
317 begin_move_insn,
318 advance_target_bb,
320 save_ebb_state,
321 restore_ebb_state,
323 SCHED_EBB
324 /* We can create new blocks in begin_schedule_ready (). */
325 | NEW_BBS
328 /* Returns the earliest block in EBB currently being processed where a
329 "similar load" 'insn2' is found, and hence LOAD_INSN can move
330 speculatively into the found block. All the following must hold:
332 (1) both loads have 1 base register (PFREE_CANDIDATEs).
333 (2) load_insn and load2 have a def-use dependence upon
334 the same insn 'insn1'.
336 From all these we can conclude that the two loads access memory
337 addresses that differ at most by a constant, and hence if moving
338 load_insn would cause an exception, it would have been caused by
339 load2 anyhow.
341 The function uses list (given by LAST_BLOCK) of already processed
342 blocks in EBB. The list is formed in `add_deps_for_risky_insns'. */
344 static basic_block
345 earliest_block_with_similiar_load (basic_block last_block, rtx load_insn)
347 sd_iterator_def back_sd_it;
348 dep_t back_dep;
349 basic_block bb, earliest_block = NULL;
351 FOR_EACH_DEP (load_insn, SD_LIST_BACK, back_sd_it, back_dep)
353 rtx_insn *insn1 = DEP_PRO (back_dep);
355 if (DEP_TYPE (back_dep) == REG_DEP_TRUE)
356 /* Found a DEF-USE dependence (insn1, load_insn). */
358 sd_iterator_def fore_sd_it;
359 dep_t fore_dep;
361 FOR_EACH_DEP (insn1, SD_LIST_FORW, fore_sd_it, fore_dep)
363 rtx_insn *insn2 = DEP_CON (fore_dep);
364 basic_block insn2_block = BLOCK_FOR_INSN (insn2);
366 if (DEP_TYPE (fore_dep) == REG_DEP_TRUE)
368 if (earliest_block != NULL
369 && earliest_block->index < insn2_block->index)
370 continue;
372 /* Found a DEF-USE dependence (insn1, insn2). */
373 if (haifa_classify_insn (insn2) != PFREE_CANDIDATE)
374 /* insn2 not guaranteed to be a 1 base reg load. */
375 continue;
377 for (bb = last_block; bb; bb = (basic_block) bb->aux)
378 if (insn2_block == bb)
379 break;
381 if (!bb)
382 /* insn2 is the similar load. */
383 earliest_block = insn2_block;
389 return earliest_block;
392 /* The following function adds dependencies between jumps and risky
393 insns in given ebb. */
395 static void
396 add_deps_for_risky_insns (rtx_insn *head, rtx_insn *tail)
398 rtx_insn *insn, *prev;
399 int classification;
400 rtx_insn *last_jump = NULL;
401 rtx_insn *next_tail = NEXT_INSN (tail);
402 basic_block last_block = NULL, bb;
404 for (insn = head; insn != next_tail; insn = NEXT_INSN (insn))
406 add_delay_dependencies (insn);
407 if (control_flow_insn_p (insn))
409 bb = BLOCK_FOR_INSN (insn);
410 bb->aux = last_block;
411 last_block = bb;
412 /* Ensure blocks stay in the same order. */
413 if (last_jump)
414 add_dependence (insn, last_jump, REG_DEP_ANTI);
415 last_jump = insn;
417 else if (INSN_P (insn) && last_jump != NULL_RTX)
419 classification = haifa_classify_insn (insn);
420 prev = last_jump;
422 switch (classification)
424 case PFREE_CANDIDATE:
425 if (flag_schedule_speculative_load)
427 bb = earliest_block_with_similiar_load (last_block, insn);
428 if (bb)
430 bb = (basic_block) bb->aux;
431 if (!bb)
432 break;
433 prev = BB_END (bb);
436 /* Fall through. */
437 case TRAP_RISKY:
438 case IRISKY:
439 case PRISKY_CANDIDATE:
440 /* ??? We could implement better checking PRISKY_CANDIDATEs
441 analogous to sched-rgn.c. */
442 /* We can not change the mode of the backward
443 dependency because REG_DEP_ANTI has the lowest
444 rank. */
445 if (! sched_insns_conditions_mutex_p (insn, prev))
447 if ((current_sched_info->flags & DO_SPECULATION)
448 && (spec_info->mask & BEGIN_CONTROL))
450 dep_def _dep, *dep = &_dep;
452 init_dep (dep, prev, insn, REG_DEP_ANTI);
454 if (current_sched_info->flags & USE_DEPS_LIST)
456 DEP_STATUS (dep) = set_dep_weak (DEP_ANTI, BEGIN_CONTROL,
457 MAX_DEP_WEAK);
460 sd_add_or_update_dep (dep, false);
462 else
463 add_dependence (insn, prev, REG_DEP_CONTROL);
466 break;
468 default:
469 break;
473 /* Maintain the invariant that bb->aux is clear after use. */
474 while (last_block)
476 bb = (basic_block) last_block->aux;
477 last_block->aux = NULL;
478 last_block = bb;
482 /* Schedule a single extended basic block, defined by the boundaries
483 HEAD and TAIL.
485 We change our expectations about scheduler behaviour depending on
486 whether MODULO_SCHEDULING is true. If it is, we expect that the
487 caller has already called set_modulo_params and created delay pairs
488 as appropriate. If the modulo schedule failed, we return
489 NULL_RTX. */
491 basic_block
492 schedule_ebb (rtx_insn *head, rtx_insn *tail, bool modulo_scheduling)
494 basic_block first_bb, target_bb;
495 struct deps_desc tmp_deps;
496 bool success;
498 /* Blah. We should fix the rest of the code not to get confused by
499 a note or two. */
500 while (head != tail)
502 if (NOTE_P (head) || DEBUG_INSN_P (head))
503 head = NEXT_INSN (head);
504 else if (NOTE_P (tail) || DEBUG_INSN_P (tail))
505 tail = PREV_INSN (tail);
506 else if (LABEL_P (head))
507 head = NEXT_INSN (head);
508 else
509 break;
512 first_bb = BLOCK_FOR_INSN (head);
513 last_bb = BLOCK_FOR_INSN (tail);
515 if (no_real_insns_p (head, tail))
516 return BLOCK_FOR_INSN (tail);
518 gcc_assert (INSN_P (head) && INSN_P (tail));
520 if (!bitmap_bit_p (&dont_calc_deps, first_bb->index))
522 init_deps_global ();
524 /* Compute dependencies. */
525 init_deps (&tmp_deps, false);
526 sched_analyze (&tmp_deps, head, tail);
527 free_deps (&tmp_deps);
529 add_deps_for_risky_insns (head, tail);
531 if (targetm.sched.dependencies_evaluation_hook)
532 targetm.sched.dependencies_evaluation_hook (head, tail);
534 finish_deps_global ();
536 else
537 /* Only recovery blocks can have their dependencies already calculated,
538 and they always are single block ebbs. */
539 gcc_assert (first_bb == last_bb);
541 /* Set priorities. */
542 current_sched_info->sched_max_insns_priority = 0;
543 rgn_n_insns = set_priorities (head, tail);
544 current_sched_info->sched_max_insns_priority++;
546 current_sched_info->prev_head = PREV_INSN (head);
547 current_sched_info->next_tail = NEXT_INSN (tail);
549 remove_notes (head, tail);
551 unlink_bb_notes (first_bb, last_bb);
553 target_bb = first_bb;
555 /* Make ready list big enough to hold all the instructions from the ebb. */
556 sched_extend_ready_list (rgn_n_insns);
557 success = schedule_block (&target_bb, NULL);
558 gcc_assert (success || modulo_scheduling);
560 /* Free ready list. */
561 sched_finish_ready_list ();
563 /* We might pack all instructions into fewer blocks,
564 so we may made some of them empty. Can't assert (b == last_bb). */
566 /* Sanity check: verify that all region insns were scheduled. */
567 gcc_assert (modulo_scheduling || sched_rgn_n_insns == rgn_n_insns);
569 /* Free dependencies. */
570 sched_free_deps (current_sched_info->head, current_sched_info->tail, true);
572 gcc_assert (haifa_recovery_bb_ever_added_p
573 || deps_pools_are_empty_p ());
575 if (EDGE_COUNT (last_bb->preds) == 0)
576 /* LAST_BB is unreachable. */
578 gcc_assert (first_bb != last_bb
579 && EDGE_COUNT (last_bb->succs) == 0);
580 last_bb = last_bb->prev_bb;
581 delete_basic_block (last_bb->next_bb);
584 return success ? last_bb : NULL;
587 /* Perform initializations before running schedule_ebbs or a single
588 schedule_ebb. */
589 void
590 schedule_ebbs_init (void)
592 /* Setup infos. */
594 memcpy (&ebb_common_sched_info, &haifa_common_sched_info,
595 sizeof (ebb_common_sched_info));
597 ebb_common_sched_info.fix_recovery_cfg = ebb_fix_recovery_cfg;
598 ebb_common_sched_info.add_block = ebb_add_block;
599 ebb_common_sched_info.sched_pass_id = SCHED_EBB_PASS;
601 common_sched_info = &ebb_common_sched_info;
602 sched_deps_info = &ebb_sched_deps_info;
603 current_sched_info = &ebb_sched_info;
606 haifa_sched_init ();
608 compute_bb_for_insn ();
610 /* Initialize DONT_CALC_DEPS and ebb-{start, end} markers. */
611 bitmap_initialize (&dont_calc_deps, 0);
612 bitmap_clear (&dont_calc_deps);
615 /* Perform cleanups after scheduling using schedules_ebbs or schedule_ebb. */
616 void
617 schedule_ebbs_finish (void)
619 bitmap_clear (&dont_calc_deps);
621 /* Reposition the prologue and epilogue notes in case we moved the
622 prologue/epilogue insns. */
623 if (reload_completed)
624 reposition_prologue_and_epilogue_notes ();
626 haifa_sched_finish ();
629 /* The main entry point in this file. */
631 void
632 schedule_ebbs (void)
634 basic_block bb;
635 int probability_cutoff;
636 rtx_insn *tail;
638 /* Taking care of this degenerate case makes the rest of
639 this code simpler. */
640 if (n_basic_blocks_for_fn (cfun) == NUM_FIXED_BLOCKS)
641 return;
643 if (profile_info && flag_branch_probabilities)
644 probability_cutoff = PARAM_VALUE (TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK);
645 else
646 probability_cutoff = PARAM_VALUE (TRACER_MIN_BRANCH_PROBABILITY);
647 probability_cutoff = REG_BR_PROB_BASE / 100 * probability_cutoff;
649 schedule_ebbs_init ();
651 /* Schedule every region in the subroutine. */
652 FOR_EACH_BB_FN (bb, cfun)
654 rtx_insn *head = BB_HEAD (bb);
656 if (bb->flags & BB_DISABLE_SCHEDULE)
657 continue;
659 for (;;)
661 edge e;
662 tail = BB_END (bb);
663 if (bb->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)
664 || LABEL_P (BB_HEAD (bb->next_bb)))
665 break;
666 e = find_fallthru_edge (bb->succs);
667 if (! e)
668 break;
669 if (e->probability <= probability_cutoff)
670 break;
671 if (e->dest->flags & BB_DISABLE_SCHEDULE)
672 break;
673 bb = bb->next_bb;
676 bb = schedule_ebb (head, tail, false);
678 schedule_ebbs_finish ();
681 /* INSN has been added to/removed from current ebb. */
682 static void
683 ebb_add_remove_insn (rtx_insn *insn ATTRIBUTE_UNUSED, int remove_p)
685 if (!remove_p)
686 rgn_n_insns++;
687 else
688 rgn_n_insns--;
691 /* BB was added to ebb after AFTER. */
692 static void
693 ebb_add_block (basic_block bb, basic_block after)
695 /* Recovery blocks are always bounded by BARRIERS,
696 therefore, they always form single block EBB,
697 therefore, we can use rec->index to identify such EBBs. */
698 if (after == EXIT_BLOCK_PTR_FOR_FN (cfun))
699 bitmap_set_bit (&dont_calc_deps, bb->index);
700 else if (after == last_bb)
701 last_bb = bb;
704 /* Return next block in ebb chain. For parameter meaning please refer to
705 sched-int.h: struct sched_info: advance_target_bb. */
706 static basic_block
707 advance_target_bb (basic_block bb, rtx_insn *insn)
709 if (insn)
711 if (BLOCK_FOR_INSN (insn) != bb
712 && control_flow_insn_p (insn)
713 /* We handle interblock movement of the speculation check
714 or over a speculation check in
715 haifa-sched.c: move_block_after_check (). */
716 && !IS_SPECULATION_BRANCHY_CHECK_P (insn)
717 && !IS_SPECULATION_BRANCHY_CHECK_P (BB_END (bb)))
719 /* Assert that we don't move jumps across blocks. */
720 gcc_assert (!control_flow_insn_p (BB_END (bb))
721 && NOTE_INSN_BASIC_BLOCK_P (BB_HEAD (bb->next_bb)));
722 return bb;
724 else
725 return 0;
727 else
728 /* Return next non empty block. */
732 gcc_assert (bb != last_bb);
734 bb = bb->next_bb;
736 while (bb_note (bb) == BB_END (bb));
738 return bb;
742 /* Fix internal data after interblock movement of jump instruction.
743 For parameter meaning please refer to
744 sched-int.h: struct sched_info: fix_recovery_cfg. */
745 static void
746 ebb_fix_recovery_cfg (int bbi ATTRIBUTE_UNUSED, int jump_bbi,
747 int jump_bb_nexti)
749 gcc_assert (last_bb->index != bbi);
751 if (jump_bb_nexti == last_bb->index)
752 last_bb = BASIC_BLOCK_FOR_FN (cfun, jump_bbi);
755 #endif /* INSN_SCHEDULING */