1 /* Loop unrolling and peeling.
2 Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 2, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
23 #include "coretypes.h"
26 #include "hard-reg-set.h"
28 #include "basic-block.h"
30 #include "cfglayout.h"
37 /* This pass performs loop unrolling and peeling. We only perform these
38 optimizations on innermost loops (with single exception) because
39 the impact on performance is greatest here, and we want to avoid
40 unnecessary code size growth. The gain is caused by greater sequentiality
41 of code, better code to optimize for further passes and in some cases
42 by fewer testings of exit conditions. The main problem is code growth,
43 that impacts performance negatively due to effect of caches.
47 -- complete peeling of once-rolling loops; this is the above mentioned
48 exception, as this causes loop to be cancelled completely and
49 does not cause code growth
50 -- complete peeling of loops that roll (small) constant times.
51 -- simple peeling of first iterations of loops that do not roll much
52 (according to profile feedback)
53 -- unrolling of loops that roll constant times; this is almost always
54 win, as we get rid of exit condition tests.
55 -- unrolling of loops that roll number of times that we can compute
56 in runtime; we also get rid of exit condition tests here, but there
57 is the extra expense for calculating the number of iterations
58 -- simple unrolling of remaining loops; this is performed only if we
59 are asked to, as the gain is questionable in this case and often
60 it may even slow down the code
61 For more detailed descriptions of each of those, see comments at
62 appropriate function below.
64 There is a lot of parameters (defined and described in params.def) that
65 control how much we unroll/peel.
67 ??? A great problem is that we don't have a good way how to determine
68 how many times we should unroll the loop; the experiments I have made
69 showed that this choice may affect performance in order of several %.
72 /* Information about induction variables to split. */
76 rtx insn; /* The insn in that the induction variable occurs. */
77 rtx base_var; /* The variable on that the values in the further
78 iterations are based. */
79 rtx step; /* Step of the induction variable. */
81 unsigned loc[3]; /* Location where the definition of the induction
82 variable occurs in the insn. For example if
83 N_LOC is 2, the expression is located at
84 XEXP (XEXP (single_set, loc[0]), loc[1]). */
87 /* Information about accumulators to expand. */
91 rtx insn; /* The insn in that the variable expansion occurs. */
92 rtx reg; /* The accumulator which is expanded. */
93 VEC(rtx,heap) *var_expansions; /* The copies of the accumulator which is expanded. */
94 enum rtx_code op; /* The type of the accumulation - addition, subtraction
96 int expansion_count; /* Count the number of expansions generated so far. */
97 int reuse_expansion; /* The expansion we intend to reuse to expand
98 the accumulator. If REUSE_EXPANSION is 0 reuse
99 the original accumulator. Else use
100 var_expansions[REUSE_EXPANSION - 1]. */
103 /* Information about optimization applied in
104 the unrolled loop. */
108 htab_t insns_to_split; /* A hashtable of insns to split. */
109 htab_t insns_with_var_to_expand; /* A hashtable of insns with accumulators
111 unsigned first_new_block; /* The first basic block that was
113 basic_block loop_exit; /* The loop exit basic block. */
114 basic_block loop_preheader; /* The loop preheader basic block. */
117 static void decide_unrolling_and_peeling (struct loops *, int);
118 static void peel_loops_completely (struct loops *, int);
119 static void decide_peel_simple (struct loop *, int);
120 static void decide_peel_once_rolling (struct loop *, int);
121 static void decide_peel_completely (struct loop *, int);
122 static void decide_unroll_stupid (struct loop *, int);
123 static void decide_unroll_constant_iterations (struct loop *, int);
124 static void decide_unroll_runtime_iterations (struct loop *, int);
125 static void peel_loop_simple (struct loops *, struct loop *);
126 static void peel_loop_completely (struct loops *, struct loop *);
127 static void unroll_loop_stupid (struct loops *, struct loop *);
128 static void unroll_loop_constant_iterations (struct loops *, struct loop *);
129 static void unroll_loop_runtime_iterations (struct loops *, struct loop *);
130 static struct opt_info *analyze_insns_in_loop (struct loop *);
131 static void opt_info_start_duplication (struct opt_info *);
132 static void apply_opt_in_copies (struct opt_info *, unsigned, bool, bool);
133 static void free_opt_info (struct opt_info *);
134 static struct var_to_expand *analyze_insn_to_expand_var (struct loop*, rtx);
135 static bool referenced_in_one_insn_in_loop_p (struct loop *, rtx);
136 static struct iv_to_split *analyze_iv_to_split_insn (rtx);
137 static void expand_var_during_unrolling (struct var_to_expand *, rtx);
138 static int insert_var_expansion_initialization (void **, void *);
139 static int combine_var_copies_in_loop_exit (void **, void *);
140 static int release_var_copies (void **, void *);
141 static rtx get_expansion (struct var_to_expand *);
143 /* Unroll and/or peel (depending on FLAGS) LOOPS. */
145 unroll_and_peel_loops (struct loops *loops, int flags)
147 struct loop *loop, *next;
150 /* First perform complete loop peeling (it is almost surely a win,
151 and affects parameters for further decision a lot). */
152 peel_loops_completely (loops, flags);
154 /* Now decide rest of unrolling and peeling. */
155 decide_unrolling_and_peeling (loops, flags);
157 loop = loops->tree_root;
161 /* Scan the loops, inner ones first. */
162 while (loop != loops->tree_root)
174 /* And perform the appropriate transformations. */
175 switch (loop->lpt_decision.decision)
177 case LPT_PEEL_COMPLETELY:
180 case LPT_PEEL_SIMPLE:
181 peel_loop_simple (loops, loop);
183 case LPT_UNROLL_CONSTANT:
184 unroll_loop_constant_iterations (loops, loop);
186 case LPT_UNROLL_RUNTIME:
187 unroll_loop_runtime_iterations (loops, loop);
189 case LPT_UNROLL_STUPID:
190 unroll_loop_stupid (loops, loop);
200 #ifdef ENABLE_CHECKING
201 verify_dominators (CDI_DOMINATORS);
202 verify_loop_structure (loops);
211 /* Check whether exit of the LOOP is at the end of loop body. */
214 loop_exit_at_end_p (struct loop *loop)
216 struct niter_desc *desc = get_simple_loop_desc (loop);
219 if (desc->in_edge->dest != loop->latch)
222 /* Check that the latch is empty. */
223 FOR_BB_INSNS (loop->latch, insn)
232 /* Check whether to peel LOOPS (depending on FLAGS) completely and do so. */
234 peel_loops_completely (struct loops *loops, int flags)
239 /* Scan the loops, the inner ones first. */
240 for (i = loops->num - 1; i > 0; i--)
242 loop = loops->parray[i];
246 loop->lpt_decision.decision = LPT_NONE;
250 "\n;; *** Considering loop %d for complete peeling ***\n",
253 loop->ninsns = num_loop_insns (loop);
255 decide_peel_once_rolling (loop, flags);
256 if (loop->lpt_decision.decision == LPT_NONE)
257 decide_peel_completely (loop, flags);
259 if (loop->lpt_decision.decision == LPT_PEEL_COMPLETELY)
261 peel_loop_completely (loops, loop);
262 #ifdef ENABLE_CHECKING
263 verify_dominators (CDI_DOMINATORS);
264 verify_loop_structure (loops);
270 /* Decide whether unroll or peel LOOPS (depending on FLAGS) and how much. */
272 decide_unrolling_and_peeling (struct loops *loops, int flags)
274 struct loop *loop = loops->tree_root, *next;
279 /* Scan the loops, inner ones first. */
280 while (loop != loops->tree_root)
291 loop->lpt_decision.decision = LPT_NONE;
294 fprintf (dump_file, "\n;; *** Considering loop %d ***\n", loop->num);
296 /* Do not peel cold areas. */
297 if (!maybe_hot_bb_p (loop->header))
300 fprintf (dump_file, ";; Not considering loop, cold area\n");
305 /* Can the loop be manipulated? */
306 if (!can_duplicate_loop_p (loop))
310 ";; Not considering loop, cannot duplicate\n");
315 /* Skip non-innermost loops. */
319 fprintf (dump_file, ";; Not considering loop, is not innermost\n");
324 loop->ninsns = num_loop_insns (loop);
325 loop->av_ninsns = average_num_loop_insns (loop);
327 /* Try transformations one by one in decreasing order of
330 decide_unroll_constant_iterations (loop, flags);
331 if (loop->lpt_decision.decision == LPT_NONE)
332 decide_unroll_runtime_iterations (loop, flags);
333 if (loop->lpt_decision.decision == LPT_NONE)
334 decide_unroll_stupid (loop, flags);
335 if (loop->lpt_decision.decision == LPT_NONE)
336 decide_peel_simple (loop, flags);
342 /* Decide whether the LOOP is once rolling and suitable for complete
345 decide_peel_once_rolling (struct loop *loop, int flags ATTRIBUTE_UNUSED)
347 struct niter_desc *desc;
350 fprintf (dump_file, "\n;; Considering peeling once rolling loop\n");
352 /* Is the loop small enough? */
353 if ((unsigned) PARAM_VALUE (PARAM_MAX_ONCE_PEELED_INSNS) < loop->ninsns)
356 fprintf (dump_file, ";; Not considering loop, is too big\n");
360 /* Check for simple loops. */
361 desc = get_simple_loop_desc (loop);
363 /* Check number of iterations. */
372 ";; Unable to prove that the loop rolls exactly once\n");
378 fprintf (dump_file, ";; Decided to peel exactly once rolling loop\n");
379 loop->lpt_decision.decision = LPT_PEEL_COMPLETELY;
382 /* Decide whether the LOOP is suitable for complete peeling. */
384 decide_peel_completely (struct loop *loop, int flags ATTRIBUTE_UNUSED)
387 struct niter_desc *desc;
390 fprintf (dump_file, "\n;; Considering peeling completely\n");
392 /* Skip non-innermost loops. */
396 fprintf (dump_file, ";; Not considering loop, is not innermost\n");
400 /* Do not peel cold areas. */
401 if (!maybe_hot_bb_p (loop->header))
404 fprintf (dump_file, ";; Not considering loop, cold area\n");
408 /* Can the loop be manipulated? */
409 if (!can_duplicate_loop_p (loop))
413 ";; Not considering loop, cannot duplicate\n");
417 /* npeel = number of iterations to peel. */
418 npeel = PARAM_VALUE (PARAM_MAX_COMPLETELY_PEELED_INSNS) / loop->ninsns;
419 if (npeel > (unsigned) PARAM_VALUE (PARAM_MAX_COMPLETELY_PEEL_TIMES))
420 npeel = PARAM_VALUE (PARAM_MAX_COMPLETELY_PEEL_TIMES);
422 /* Is the loop small enough? */
426 fprintf (dump_file, ";; Not considering loop, is too big\n");
430 /* Check for simple loops. */
431 desc = get_simple_loop_desc (loop);
433 /* Check number of iterations. */
441 ";; Unable to prove that the loop iterates constant times\n");
445 if (desc->niter > npeel - 1)
450 ";; Not peeling loop completely, rolls too much (");
451 fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC, desc->niter);
452 fprintf (dump_file, " iterations > %d [maximum peelings])\n", npeel);
459 fprintf (dump_file, ";; Decided to peel loop completely\n");
460 loop->lpt_decision.decision = LPT_PEEL_COMPLETELY;
463 /* Peel all iterations of LOOP, remove exit edges and cancel the loop
464 completely. The transformation done:
466 for (i = 0; i < 4; i++)
478 peel_loop_completely (struct loops *loops, struct loop *loop)
481 unsigned HOST_WIDE_INT npeel;
482 unsigned n_remove_edges, i;
483 edge *remove_edges, ein;
484 struct niter_desc *desc = get_simple_loop_desc (loop);
485 struct opt_info *opt_info = NULL;
493 wont_exit = sbitmap_alloc (npeel + 1);
494 sbitmap_ones (wont_exit);
495 RESET_BIT (wont_exit, 0);
496 if (desc->noloop_assumptions)
497 RESET_BIT (wont_exit, 1);
499 remove_edges = XCNEWVEC (edge, npeel);
502 if (flag_split_ivs_in_unroller)
503 opt_info = analyze_insns_in_loop (loop);
505 opt_info_start_duplication (opt_info);
506 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
508 wont_exit, desc->out_edge,
509 remove_edges, &n_remove_edges,
510 DLTHE_FLAG_UPDATE_FREQ
511 | DLTHE_FLAG_COMPLETTE_PEEL
513 ? DLTHE_RECORD_COPY_NUMBER : 0));
520 apply_opt_in_copies (opt_info, npeel, false, true);
521 free_opt_info (opt_info);
524 /* Remove the exit edges. */
525 for (i = 0; i < n_remove_edges; i++)
526 remove_path (loops, remove_edges[i]);
531 free_simple_loop_desc (loop);
533 /* Now remove the unreachable part of the last iteration and cancel
535 remove_path (loops, ein);
538 fprintf (dump_file, ";; Peeled loop completely, %d times\n", (int) npeel);
541 /* Decide whether to unroll LOOP iterating constant number of times
545 decide_unroll_constant_iterations (struct loop *loop, int flags)
547 unsigned nunroll, nunroll_by_av, best_copies, best_unroll = 0, n_copies, i;
548 struct niter_desc *desc;
550 if (!(flags & UAP_UNROLL))
552 /* We were not asked to, just return back silently. */
558 "\n;; Considering unrolling loop with constant "
559 "number of iterations\n");
561 /* nunroll = total number of copies of the original loop body in
562 unrolled loop (i.e. if it is 2, we have to duplicate loop body once. */
563 nunroll = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / loop->ninsns;
565 = PARAM_VALUE (PARAM_MAX_AVERAGE_UNROLLED_INSNS) / loop->av_ninsns;
566 if (nunroll > nunroll_by_av)
567 nunroll = nunroll_by_av;
568 if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES))
569 nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES);
571 /* Skip big loops. */
575 fprintf (dump_file, ";; Not considering loop, is too big\n");
579 /* Check for simple loops. */
580 desc = get_simple_loop_desc (loop);
582 /* Check number of iterations. */
583 if (!desc->simple_p || !desc->const_iter || desc->assumptions)
587 ";; Unable to prove that the loop iterates constant times\n");
591 /* Check whether the loop rolls enough to consider. */
592 if (desc->niter < 2 * nunroll)
595 fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n");
599 /* Success; now compute number of iterations to unroll. We alter
600 nunroll so that as few as possible copies of loop body are
601 necessary, while still not decreasing the number of unrollings
602 too much (at most by 1). */
603 best_copies = 2 * nunroll + 10;
606 if (i - 1 >= desc->niter)
609 for (; i >= nunroll - 1; i--)
611 unsigned exit_mod = desc->niter % (i + 1);
613 if (!loop_exit_at_end_p (loop))
614 n_copies = exit_mod + i + 1;
615 else if (exit_mod != (unsigned) i
616 || desc->noloop_assumptions != NULL_RTX)
617 n_copies = exit_mod + i + 2;
621 if (n_copies < best_copies)
623 best_copies = n_copies;
629 fprintf (dump_file, ";; max_unroll %d (%d copies, initial %d).\n",
630 best_unroll + 1, best_copies, nunroll);
632 loop->lpt_decision.decision = LPT_UNROLL_CONSTANT;
633 loop->lpt_decision.times = best_unroll;
637 ";; Decided to unroll the constant times rolling loop, %d times.\n",
638 loop->lpt_decision.times);
641 /* Unroll LOOP with constant number of iterations LOOP->LPT_DECISION.TIMES + 1
642 times. The transformation does this:
644 for (i = 0; i < 102; i++)
661 unroll_loop_constant_iterations (struct loops *loops, struct loop *loop)
663 unsigned HOST_WIDE_INT niter;
666 unsigned n_remove_edges, i;
668 unsigned max_unroll = loop->lpt_decision.times;
669 struct niter_desc *desc = get_simple_loop_desc (loop);
670 bool exit_at_end = loop_exit_at_end_p (loop);
671 struct opt_info *opt_info = NULL;
676 /* Should not get here (such loop should be peeled instead). */
677 gcc_assert (niter > max_unroll + 1);
679 exit_mod = niter % (max_unroll + 1);
681 wont_exit = sbitmap_alloc (max_unroll + 1);
682 sbitmap_ones (wont_exit);
684 remove_edges = XCNEWVEC (edge, max_unroll + exit_mod + 1);
686 if (flag_split_ivs_in_unroller
687 || flag_variable_expansion_in_unroller)
688 opt_info = analyze_insns_in_loop (loop);
692 /* The exit is not at the end of the loop; leave exit test
693 in the first copy, so that the loops that start with test
694 of exit condition have continuous body after unrolling. */
697 fprintf (dump_file, ";; Condition on beginning of loop.\n");
699 /* Peel exit_mod iterations. */
700 RESET_BIT (wont_exit, 0);
701 if (desc->noloop_assumptions)
702 RESET_BIT (wont_exit, 1);
706 opt_info_start_duplication (opt_info);
707 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
709 wont_exit, desc->out_edge,
710 remove_edges, &n_remove_edges,
711 DLTHE_FLAG_UPDATE_FREQ
712 | (opt_info && exit_mod > 1
713 ? DLTHE_RECORD_COPY_NUMBER
717 if (opt_info && exit_mod > 1)
718 apply_opt_in_copies (opt_info, exit_mod, false, false);
720 desc->noloop_assumptions = NULL_RTX;
721 desc->niter -= exit_mod;
722 desc->niter_max -= exit_mod;
725 SET_BIT (wont_exit, 1);
729 /* Leave exit test in last copy, for the same reason as above if
730 the loop tests the condition at the end of loop body. */
733 fprintf (dump_file, ";; Condition on end of loop.\n");
735 /* We know that niter >= max_unroll + 2; so we do not need to care of
736 case when we would exit before reaching the loop. So just peel
737 exit_mod + 1 iterations. */
738 if (exit_mod != max_unroll
739 || desc->noloop_assumptions)
741 RESET_BIT (wont_exit, 0);
742 if (desc->noloop_assumptions)
743 RESET_BIT (wont_exit, 1);
745 opt_info_start_duplication (opt_info);
746 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
748 wont_exit, desc->out_edge,
749 remove_edges, &n_remove_edges,
750 DLTHE_FLAG_UPDATE_FREQ
751 | (opt_info && exit_mod > 0
752 ? DLTHE_RECORD_COPY_NUMBER
756 if (opt_info && exit_mod > 0)
757 apply_opt_in_copies (opt_info, exit_mod + 1, false, false);
759 desc->niter -= exit_mod + 1;
760 desc->niter_max -= exit_mod + 1;
761 desc->noloop_assumptions = NULL_RTX;
763 SET_BIT (wont_exit, 0);
764 SET_BIT (wont_exit, 1);
767 RESET_BIT (wont_exit, max_unroll);
770 /* Now unroll the loop. */
772 opt_info_start_duplication (opt_info);
773 ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop),
775 wont_exit, desc->out_edge,
776 remove_edges, &n_remove_edges,
777 DLTHE_FLAG_UPDATE_FREQ
779 ? DLTHE_RECORD_COPY_NUMBER
785 apply_opt_in_copies (opt_info, max_unroll, true, true);
786 free_opt_info (opt_info);
793 basic_block exit_block = get_bb_copy (desc->in_edge->src);
794 /* Find a new in and out edge; they are in the last copy we have made. */
796 if (EDGE_SUCC (exit_block, 0)->dest == desc->out_edge->dest)
798 desc->out_edge = EDGE_SUCC (exit_block, 0);
799 desc->in_edge = EDGE_SUCC (exit_block, 1);
803 desc->out_edge = EDGE_SUCC (exit_block, 1);
804 desc->in_edge = EDGE_SUCC (exit_block, 0);
808 desc->niter /= max_unroll + 1;
809 desc->niter_max /= max_unroll + 1;
810 desc->niter_expr = GEN_INT (desc->niter);
812 /* Remove the edges. */
813 for (i = 0; i < n_remove_edges; i++)
814 remove_path (loops, remove_edges[i]);
819 ";; Unrolled loop %d times, constant # of iterations %i insns\n",
820 max_unroll, num_loop_insns (loop));
823 /* Decide whether to unroll LOOP iterating runtime computable number of times
826 decide_unroll_runtime_iterations (struct loop *loop, int flags)
828 unsigned nunroll, nunroll_by_av, i;
829 struct niter_desc *desc;
831 if (!(flags & UAP_UNROLL))
833 /* We were not asked to, just return back silently. */
839 "\n;; Considering unrolling loop with runtime "
840 "computable number of iterations\n");
842 /* nunroll = total number of copies of the original loop body in
843 unrolled loop (i.e. if it is 2, we have to duplicate loop body once. */
844 nunroll = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / loop->ninsns;
845 nunroll_by_av = PARAM_VALUE (PARAM_MAX_AVERAGE_UNROLLED_INSNS) / loop->av_ninsns;
846 if (nunroll > nunroll_by_av)
847 nunroll = nunroll_by_av;
848 if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES))
849 nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES);
851 /* Skip big loops. */
855 fprintf (dump_file, ";; Not considering loop, is too big\n");
859 /* Check for simple loops. */
860 desc = get_simple_loop_desc (loop);
862 /* Check simpleness. */
863 if (!desc->simple_p || desc->assumptions)
867 ";; Unable to prove that the number of iterations "
868 "can be counted in runtime\n");
872 if (desc->const_iter)
875 fprintf (dump_file, ";; Loop iterates constant times\n");
879 /* If we have profile feedback, check whether the loop rolls. */
880 if (loop->header->count && expected_loop_iterations (loop) < 2 * nunroll)
883 fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n");
887 /* Success; now force nunroll to be power of 2, as we are unable to
888 cope with overflows in computation of number of iterations. */
889 for (i = 1; 2 * i <= nunroll; i *= 2)
892 loop->lpt_decision.decision = LPT_UNROLL_RUNTIME;
893 loop->lpt_decision.times = i - 1;
897 ";; Decided to unroll the runtime computable "
898 "times rolling loop, %d times.\n",
899 loop->lpt_decision.times);
902 /* Splits edge E and inserts INSNS on it. */
905 split_edge_and_insert (edge e, rtx insns)
907 basic_block bb = split_edge (e);
908 gcc_assert (insns != NULL_RTX);
909 emit_insn_after (insns, BB_END (bb));
910 bb->flags |= BB_SUPERBLOCK;
914 /* Unroll LOOP for that we are able to count number of iterations in runtime
915 LOOP->LPT_DECISION.TIMES + 1 times. The transformation does this (with some
916 extra care for case n < 0):
918 for (i = 0; i < n; i++)
946 unroll_loop_runtime_iterations (struct loops *loops, struct loop *loop)
948 rtx old_niter, niter, init_code, branch_code, tmp;
950 basic_block preheader, *body, *dom_bbs, swtch, ezc_swtch;
954 unsigned n_peel, n_remove_edges;
955 edge *remove_edges, e;
956 bool extra_zero_check, last_may_exit;
957 unsigned max_unroll = loop->lpt_decision.times;
958 struct niter_desc *desc = get_simple_loop_desc (loop);
959 bool exit_at_end = loop_exit_at_end_p (loop);
960 struct opt_info *opt_info = NULL;
963 if (flag_split_ivs_in_unroller
964 || flag_variable_expansion_in_unroller)
965 opt_info = analyze_insns_in_loop (loop);
967 /* Remember blocks whose dominators will have to be updated. */
968 dom_bbs = XCNEWVEC (basic_block, n_basic_blocks);
971 body = get_loop_body (loop);
972 for (i = 0; i < loop->num_nodes; i++)
977 nldom = get_dominated_by (CDI_DOMINATORS, body[i], &ldom);
978 for (j = 0; j < nldom; j++)
979 if (!flow_bb_inside_loop_p (loop, ldom[j]))
980 dom_bbs[n_dom_bbs++] = ldom[j];
988 /* Leave exit in first copy (for explanation why see comment in
989 unroll_loop_constant_iterations). */
991 n_peel = max_unroll - 1;
992 extra_zero_check = true;
993 last_may_exit = false;
997 /* Leave exit in last copy (for explanation why see comment in
998 unroll_loop_constant_iterations). */
999 may_exit_copy = max_unroll;
1000 n_peel = max_unroll;
1001 extra_zero_check = false;
1002 last_may_exit = true;
1005 /* Get expression for number of iterations. */
1007 old_niter = niter = gen_reg_rtx (desc->mode);
1008 tmp = force_operand (copy_rtx (desc->niter_expr), niter);
1010 emit_move_insn (niter, tmp);
1012 /* Count modulo by ANDing it with max_unroll; we use the fact that
1013 the number of unrollings is a power of two, and thus this is correct
1014 even if there is overflow in the computation. */
1015 niter = expand_simple_binop (desc->mode, AND,
1017 GEN_INT (max_unroll),
1018 NULL_RTX, 0, OPTAB_LIB_WIDEN);
1020 init_code = get_insns ();
1023 /* Precondition the loop. */
1024 split_edge_and_insert (loop_preheader_edge (loop), init_code);
1026 remove_edges = XCNEWVEC (edge, max_unroll + n_peel + 1);
1029 wont_exit = sbitmap_alloc (max_unroll + 2);
1031 /* Peel the first copy of loop body (almost always we must leave exit test
1032 here; the only exception is when we have extra zero check and the number
1033 of iterations is reliable. Also record the place of (possible) extra
1035 sbitmap_zero (wont_exit);
1036 if (extra_zero_check
1037 && !desc->noloop_assumptions)
1038 SET_BIT (wont_exit, 1);
1039 ezc_swtch = loop_preheader_edge (loop)->src;
1040 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
1042 wont_exit, desc->out_edge,
1043 remove_edges, &n_remove_edges,
1044 DLTHE_FLAG_UPDATE_FREQ);
1047 /* Record the place where switch will be built for preconditioning. */
1048 swtch = split_edge (loop_preheader_edge (loop));
1050 for (i = 0; i < n_peel; i++)
1052 /* Peel the copy. */
1053 sbitmap_zero (wont_exit);
1054 if (i != n_peel - 1 || !last_may_exit)
1055 SET_BIT (wont_exit, 1);
1056 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
1058 wont_exit, desc->out_edge,
1059 remove_edges, &n_remove_edges,
1060 DLTHE_FLAG_UPDATE_FREQ);
1063 /* Create item for switch. */
1064 j = n_peel - i - (extra_zero_check ? 0 : 1);
1065 p = REG_BR_PROB_BASE / (i + 2);
1067 preheader = split_edge (loop_preheader_edge (loop));
1068 branch_code = compare_and_jump_seq (copy_rtx (niter), GEN_INT (j), EQ,
1069 block_label (preheader), p,
1072 swtch = split_edge_and_insert (single_pred_edge (swtch), branch_code);
1073 set_immediate_dominator (CDI_DOMINATORS, preheader, swtch);
1074 single_pred_edge (swtch)->probability = REG_BR_PROB_BASE - p;
1075 e = make_edge (swtch, preheader,
1076 single_succ_edge (swtch)->flags & EDGE_IRREDUCIBLE_LOOP);
1080 if (extra_zero_check)
1082 /* Add branch for zero iterations. */
1083 p = REG_BR_PROB_BASE / (max_unroll + 1);
1085 preheader = split_edge (loop_preheader_edge (loop));
1086 branch_code = compare_and_jump_seq (copy_rtx (niter), const0_rtx, EQ,
1087 block_label (preheader), p,
1090 swtch = split_edge_and_insert (single_succ_edge (swtch), branch_code);
1091 set_immediate_dominator (CDI_DOMINATORS, preheader, swtch);
1092 single_succ_edge (swtch)->probability = REG_BR_PROB_BASE - p;
1093 e = make_edge (swtch, preheader,
1094 single_succ_edge (swtch)->flags & EDGE_IRREDUCIBLE_LOOP);
1098 /* Recount dominators for outer blocks. */
1099 iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, n_dom_bbs);
1101 /* And unroll loop. */
1103 sbitmap_ones (wont_exit);
1104 RESET_BIT (wont_exit, may_exit_copy);
1105 opt_info_start_duplication (opt_info);
1107 ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop),
1109 wont_exit, desc->out_edge,
1110 remove_edges, &n_remove_edges,
1111 DLTHE_FLAG_UPDATE_FREQ
1113 ? DLTHE_RECORD_COPY_NUMBER
1119 apply_opt_in_copies (opt_info, max_unroll, true, true);
1120 free_opt_info (opt_info);
1127 basic_block exit_block = get_bb_copy (desc->in_edge->src);
1128 /* Find a new in and out edge; they are in the last copy we have
1131 if (EDGE_SUCC (exit_block, 0)->dest == desc->out_edge->dest)
1133 desc->out_edge = EDGE_SUCC (exit_block, 0);
1134 desc->in_edge = EDGE_SUCC (exit_block, 1);
1138 desc->out_edge = EDGE_SUCC (exit_block, 1);
1139 desc->in_edge = EDGE_SUCC (exit_block, 0);
1143 /* Remove the edges. */
1144 for (i = 0; i < n_remove_edges; i++)
1145 remove_path (loops, remove_edges[i]);
1146 free (remove_edges);
1148 /* We must be careful when updating the number of iterations due to
1149 preconditioning and the fact that the value must be valid at entry
1150 of the loop. After passing through the above code, we see that
1151 the correct new number of iterations is this: */
1152 gcc_assert (!desc->const_iter);
1154 simplify_gen_binary (UDIV, desc->mode, old_niter,
1155 GEN_INT (max_unroll + 1));
1156 desc->niter_max /= max_unroll + 1;
1160 simplify_gen_binary (MINUS, desc->mode, desc->niter_expr, const1_rtx);
1161 desc->noloop_assumptions = NULL_RTX;
1167 ";; Unrolled loop %d times, counting # of iterations "
1168 "in runtime, %i insns\n",
1169 max_unroll, num_loop_insns (loop));
1175 /* Decide whether to simply peel LOOP and how much. */
1177 decide_peel_simple (struct loop *loop, int flags)
1180 struct niter_desc *desc;
1182 if (!(flags & UAP_PEEL))
1184 /* We were not asked to, just return back silently. */
1189 fprintf (dump_file, "\n;; Considering simply peeling loop\n");
1191 /* npeel = number of iterations to peel. */
1192 npeel = PARAM_VALUE (PARAM_MAX_PEELED_INSNS) / loop->ninsns;
1193 if (npeel > (unsigned) PARAM_VALUE (PARAM_MAX_PEEL_TIMES))
1194 npeel = PARAM_VALUE (PARAM_MAX_PEEL_TIMES);
1196 /* Skip big loops. */
1200 fprintf (dump_file, ";; Not considering loop, is too big\n");
1204 /* Check for simple loops. */
1205 desc = get_simple_loop_desc (loop);
1207 /* Check number of iterations. */
1208 if (desc->simple_p && !desc->assumptions && desc->const_iter)
1211 fprintf (dump_file, ";; Loop iterates constant times\n");
1215 /* Do not simply peel loops with branches inside -- it increases number
1217 if (num_loop_branches (loop) > 1)
1220 fprintf (dump_file, ";; Not peeling, contains branches\n");
1224 if (loop->header->count)
1226 unsigned niter = expected_loop_iterations (loop);
1227 if (niter + 1 > npeel)
1231 fprintf (dump_file, ";; Not peeling loop, rolls too much (");
1232 fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC,
1233 (HOST_WIDEST_INT) (niter + 1));
1234 fprintf (dump_file, " iterations > %d [maximum peelings])\n",
1243 /* For now we have no good heuristics to decide whether loop peeling
1244 will be effective, so disable it. */
1247 ";; Not peeling loop, no evidence it will be profitable\n");
1252 loop->lpt_decision.decision = LPT_PEEL_SIMPLE;
1253 loop->lpt_decision.times = npeel;
1256 fprintf (dump_file, ";; Decided to simply peel the loop, %d times.\n",
1257 loop->lpt_decision.times);
1260 /* Peel a LOOP LOOP->LPT_DECISION.TIMES times. The transformation:
1266 if (!cond) goto end;
1268 if (!cond) goto end;
1275 peel_loop_simple (struct loops *loops, struct loop *loop)
1278 unsigned npeel = loop->lpt_decision.times;
1279 struct niter_desc *desc = get_simple_loop_desc (loop);
1280 struct opt_info *opt_info = NULL;
1283 if (flag_split_ivs_in_unroller && npeel > 1)
1284 opt_info = analyze_insns_in_loop (loop);
1286 wont_exit = sbitmap_alloc (npeel + 1);
1287 sbitmap_zero (wont_exit);
1289 opt_info_start_duplication (opt_info);
1291 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
1292 loops, npeel, wont_exit,
1294 NULL, DLTHE_FLAG_UPDATE_FREQ
1296 ? DLTHE_RECORD_COPY_NUMBER
1304 apply_opt_in_copies (opt_info, npeel, false, false);
1305 free_opt_info (opt_info);
1310 if (desc->const_iter)
1312 desc->niter -= npeel;
1313 desc->niter_expr = GEN_INT (desc->niter);
1314 desc->noloop_assumptions = NULL_RTX;
1318 /* We cannot just update niter_expr, as its value might be clobbered
1319 inside loop. We could handle this by counting the number into
1320 temporary just like we do in runtime unrolling, but it does not
1322 free_simple_loop_desc (loop);
1326 fprintf (dump_file, ";; Peeling loop %d times\n", npeel);
1329 /* Decide whether to unroll LOOP stupidly and how much. */
1331 decide_unroll_stupid (struct loop *loop, int flags)
1333 unsigned nunroll, nunroll_by_av, i;
1334 struct niter_desc *desc;
1336 if (!(flags & UAP_UNROLL_ALL))
1338 /* We were not asked to, just return back silently. */
1343 fprintf (dump_file, "\n;; Considering unrolling loop stupidly\n");
1345 /* nunroll = total number of copies of the original loop body in
1346 unrolled loop (i.e. if it is 2, we have to duplicate loop body once. */
1347 nunroll = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / loop->ninsns;
1349 = PARAM_VALUE (PARAM_MAX_AVERAGE_UNROLLED_INSNS) / loop->av_ninsns;
1350 if (nunroll > nunroll_by_av)
1351 nunroll = nunroll_by_av;
1352 if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES))
1353 nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES);
1355 /* Skip big loops. */
1359 fprintf (dump_file, ";; Not considering loop, is too big\n");
1363 /* Check for simple loops. */
1364 desc = get_simple_loop_desc (loop);
1366 /* Check simpleness. */
1367 if (desc->simple_p && !desc->assumptions)
1370 fprintf (dump_file, ";; The loop is simple\n");
1374 /* Do not unroll loops with branches inside -- it increases number
1376 if (num_loop_branches (loop) > 1)
1379 fprintf (dump_file, ";; Not unrolling, contains branches\n");
1383 /* If we have profile feedback, check whether the loop rolls. */
1384 if (loop->header->count
1385 && expected_loop_iterations (loop) < 2 * nunroll)
1388 fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n");
1392 /* Success. Now force nunroll to be power of 2, as it seems that this
1393 improves results (partially because of better alignments, partially
1394 because of some dark magic). */
1395 for (i = 1; 2 * i <= nunroll; i *= 2)
1398 loop->lpt_decision.decision = LPT_UNROLL_STUPID;
1399 loop->lpt_decision.times = i - 1;
1403 ";; Decided to unroll the loop stupidly, %d times.\n",
1404 loop->lpt_decision.times);
1407 /* Unroll a LOOP LOOP->LPT_DECISION.TIMES times. The transformation:
1425 unroll_loop_stupid (struct loops *loops, struct loop *loop)
1428 unsigned nunroll = loop->lpt_decision.times;
1429 struct niter_desc *desc = get_simple_loop_desc (loop);
1430 struct opt_info *opt_info = NULL;
1433 if (flag_split_ivs_in_unroller
1434 || flag_variable_expansion_in_unroller)
1435 opt_info = analyze_insns_in_loop (loop);
1438 wont_exit = sbitmap_alloc (nunroll + 1);
1439 sbitmap_zero (wont_exit);
1440 opt_info_start_duplication (opt_info);
1442 ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop),
1443 loops, nunroll, wont_exit,
1445 DLTHE_FLAG_UPDATE_FREQ
1447 ? DLTHE_RECORD_COPY_NUMBER
1453 apply_opt_in_copies (opt_info, nunroll, true, true);
1454 free_opt_info (opt_info);
1461 /* We indeed may get here provided that there are nontrivial assumptions
1462 for a loop to be really simple. We could update the counts, but the
1463 problem is that we are unable to decide which exit will be taken
1464 (not really true in case the number of iterations is constant,
1465 but noone will do anything with this information, so we do not
1467 desc->simple_p = false;
1471 fprintf (dump_file, ";; Unrolled loop %d times, %i insns\n",
1472 nunroll, num_loop_insns (loop));
1475 /* A hash function for information about insns to split. */
1478 si_info_hash (const void *ivts)
1480 return (hashval_t) INSN_UID (((struct iv_to_split *) ivts)->insn);
1483 /* An equality functions for information about insns to split. */
1486 si_info_eq (const void *ivts1, const void *ivts2)
1488 const struct iv_to_split *i1 = ivts1;
1489 const struct iv_to_split *i2 = ivts2;
1491 return i1->insn == i2->insn;
1494 /* Return a hash for VES, which is really a "var_to_expand *". */
1497 ve_info_hash (const void *ves)
1499 return (hashval_t) INSN_UID (((struct var_to_expand *) ves)->insn);
1502 /* Return true if IVTS1 and IVTS2 (which are really both of type
1503 "var_to_expand *") refer to the same instruction. */
1506 ve_info_eq (const void *ivts1, const void *ivts2)
1508 const struct var_to_expand *i1 = ivts1;
1509 const struct var_to_expand *i2 = ivts2;
1511 return i1->insn == i2->insn;
1514 /* Returns true if REG is referenced in one insn in LOOP. */
1517 referenced_in_one_insn_in_loop_p (struct loop *loop, rtx reg)
1519 basic_block *body, bb;
1524 body = get_loop_body (loop);
1525 for (i = 0; i < loop->num_nodes; i++)
1529 FOR_BB_INSNS (bb, insn)
1531 if (rtx_referenced_p (reg, insn))
1535 return (count_ref == 1);
1538 /* Determine whether INSN contains an accumulator
1539 which can be expanded into separate copies,
1540 one for each copy of the LOOP body.
1542 for (i = 0 ; i < n; i++)
1556 Return NULL if INSN contains no opportunity for expansion of accumulator.
1557 Otherwise, allocate a VAR_TO_EXPAND structure, fill it with the relevant
1558 information and return a pointer to it.
1561 static struct var_to_expand *
1562 analyze_insn_to_expand_var (struct loop *loop, rtx insn)
1564 rtx set, dest, src, op1;
1565 struct var_to_expand *ves;
1566 enum machine_mode mode1, mode2;
1568 set = single_set (insn);
1572 dest = SET_DEST (set);
1573 src = SET_SRC (set);
1575 if (GET_CODE (src) != PLUS
1576 && GET_CODE (src) != MINUS
1577 && GET_CODE (src) != MULT)
1580 /* Hmm, this is a bit paradoxical. We know that INSN is a valid insn
1581 in MD. But if there is no optab to generate the insn, we can not
1582 perform the variable expansion. This can happen if an MD provides
1583 an insn but not a named pattern to generate it, for example to avoid
1584 producing code that needs additional mode switches like for x87/mmx.
1586 So we check have_insn_for which looks for an optab for the operation
1587 in SRC. If it doesn't exist, we can't perform the expansion even
1588 though INSN is valid. */
1589 if (!have_insn_for (GET_CODE (src), GET_MODE (src)))
1595 op1 = XEXP (src, 0);
1598 && !(GET_CODE (dest) == SUBREG
1599 && REG_P (SUBREG_REG (dest))))
1602 if (!rtx_equal_p (dest, op1))
1605 if (!referenced_in_one_insn_in_loop_p (loop, dest))
1608 if (rtx_referenced_p (dest, XEXP (src, 1)))
1611 mode1 = GET_MODE (dest);
1612 mode2 = GET_MODE (XEXP (src, 1));
1613 if ((FLOAT_MODE_P (mode1)
1614 || FLOAT_MODE_P (mode2))
1615 && !flag_unsafe_math_optimizations)
1618 /* Record the accumulator to expand. */
1619 ves = XNEW (struct var_to_expand);
1621 ves->var_expansions = VEC_alloc (rtx, heap, 1);
1622 ves->reg = copy_rtx (dest);
1623 ves->op = GET_CODE (src);
1624 ves->expansion_count = 0;
1625 ves->reuse_expansion = 0;
1629 /* Determine whether there is an induction variable in INSN that
1630 we would like to split during unrolling.
1650 Return NULL if INSN contains no interesting IVs. Otherwise, allocate
1651 an IV_TO_SPLIT structure, fill it with the relevant information and return a
1654 static struct iv_to_split *
1655 analyze_iv_to_split_insn (rtx insn)
1659 struct iv_to_split *ivts;
1662 /* For now we just split the basic induction variables. Later this may be
1663 extended for example by selecting also addresses of memory references. */
1664 set = single_set (insn);
1668 dest = SET_DEST (set);
1672 if (!biv_p (insn, dest))
1675 ok = iv_analyze_result (insn, dest, &iv);
1677 /* This used to be an assert under the assumption that if biv_p returns
1678 true that iv_analyze_result must also return true. However, that
1679 assumption is not strictly correct as evidenced by pr25569.
1681 Returning NULL when iv_analyze_result returns false is safe and
1682 avoids the problems in pr25569 until the iv_analyze_* routines
1683 can be fixed, which is apparently hard and time consuming
1684 according to their author. */
1688 if (iv.step == const0_rtx
1689 || iv.mode != iv.extend_mode)
1692 /* Record the insn to split. */
1693 ivts = XNEW (struct iv_to_split);
1695 ivts->base_var = NULL_RTX;
1696 ivts->step = iv.step;
1703 /* Determines which of insns in LOOP can be optimized.
1704 Return a OPT_INFO struct with the relevant hash tables filled
1705 with all insns to be optimized. The FIRST_NEW_BLOCK field
1706 is undefined for the return value. */
1708 static struct opt_info *
1709 analyze_insns_in_loop (struct loop *loop)
1711 basic_block *body, bb;
1713 struct opt_info *opt_info = XCNEW (struct opt_info);
1715 struct iv_to_split *ivts = NULL;
1716 struct var_to_expand *ves = NULL;
1719 VEC (edge, heap) *edges = get_loop_exit_edges (loop);
1721 bool can_apply = false;
1723 iv_analysis_loop_init (loop);
1725 body = get_loop_body (loop);
1727 if (flag_split_ivs_in_unroller)
1728 opt_info->insns_to_split = htab_create (5 * loop->num_nodes,
1729 si_info_hash, si_info_eq, free);
1731 /* Record the loop exit bb and loop preheader before the unrolling. */
1732 opt_info->loop_preheader = loop_preheader_edge (loop)->src;
1734 if (VEC_length (edge, edges) == 1)
1736 exit = VEC_index (edge, edges, 0);
1737 if (!(exit->flags & EDGE_COMPLEX))
1739 opt_info->loop_exit = split_edge (exit);
1744 if (flag_variable_expansion_in_unroller
1746 opt_info->insns_with_var_to_expand = htab_create (5 * loop->num_nodes,
1747 ve_info_hash, ve_info_eq, free);
1749 for (i = 0; i < loop->num_nodes; i++)
1752 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
1755 FOR_BB_INSNS (bb, insn)
1760 if (opt_info->insns_to_split)
1761 ivts = analyze_iv_to_split_insn (insn);
1765 slot1 = htab_find_slot (opt_info->insns_to_split, ivts, INSERT);
1770 if (opt_info->insns_with_var_to_expand)
1771 ves = analyze_insn_to_expand_var (loop, insn);
1775 slot2 = htab_find_slot (opt_info->insns_with_var_to_expand, ves, INSERT);
1781 VEC_free (edge, heap, edges);
1786 /* Called just before loop duplication. Records start of duplicated area
1790 opt_info_start_duplication (struct opt_info *opt_info)
1793 opt_info->first_new_block = last_basic_block;
1796 /* Determine the number of iterations between initialization of the base
1797 variable and the current copy (N_COPY). N_COPIES is the total number
1798 of newly created copies. UNROLLING is true if we are unrolling
1799 (not peeling) the loop. */
1802 determine_split_iv_delta (unsigned n_copy, unsigned n_copies, bool unrolling)
1806 /* If we are unrolling, initialization is done in the original loop
1812 /* If we are peeling, the copy in that the initialization occurs has
1813 number 1. The original loop (number 0) is the last. */
1821 /* Locate in EXPR the expression corresponding to the location recorded
1822 in IVTS, and return a pointer to the RTX for this location. */
1825 get_ivts_expr (rtx expr, struct iv_to_split *ivts)
1830 for (i = 0; i < ivts->n_loc; i++)
1831 ret = &XEXP (*ret, ivts->loc[i]);
1836 /* Allocate basic variable for the induction variable chain. Callback for
1840 allocate_basic_variable (void **slot, void *data ATTRIBUTE_UNUSED)
1842 struct iv_to_split *ivts = *slot;
1843 rtx expr = *get_ivts_expr (single_set (ivts->insn), ivts);
1845 ivts->base_var = gen_reg_rtx (GET_MODE (expr));
1850 /* Insert initialization of basic variable of IVTS before INSN, taking
1851 the initial value from INSN. */
1854 insert_base_initialization (struct iv_to_split *ivts, rtx insn)
1856 rtx expr = copy_rtx (*get_ivts_expr (single_set (insn), ivts));
1860 expr = force_operand (expr, ivts->base_var);
1861 if (expr != ivts->base_var)
1862 emit_move_insn (ivts->base_var, expr);
1866 emit_insn_before (seq, insn);
1869 /* Replace the use of induction variable described in IVTS in INSN
1870 by base variable + DELTA * step. */
1873 split_iv (struct iv_to_split *ivts, rtx insn, unsigned delta)
1875 rtx expr, *loc, seq, incr, var;
1876 enum machine_mode mode = GET_MODE (ivts->base_var);
1879 /* Construct base + DELTA * step. */
1881 expr = ivts->base_var;
1884 incr = simplify_gen_binary (MULT, mode,
1885 ivts->step, gen_int_mode (delta, mode));
1886 expr = simplify_gen_binary (PLUS, GET_MODE (ivts->base_var),
1887 ivts->base_var, incr);
1890 /* Figure out where to do the replacement. */
1891 loc = get_ivts_expr (single_set (insn), ivts);
1893 /* If we can make the replacement right away, we're done. */
1894 if (validate_change (insn, loc, expr, 0))
1897 /* Otherwise, force EXPR into a register and try again. */
1899 var = gen_reg_rtx (mode);
1900 expr = force_operand (expr, var);
1902 emit_move_insn (var, expr);
1905 emit_insn_before (seq, insn);
1907 if (validate_change (insn, loc, var, 0))
1910 /* The last chance. Try recreating the assignment in insn
1911 completely from scratch. */
1912 set = single_set (insn);
1917 src = copy_rtx (SET_SRC (set));
1918 dest = copy_rtx (SET_DEST (set));
1919 src = force_operand (src, dest);
1921 emit_move_insn (dest, src);
1925 emit_insn_before (seq, insn);
1930 /* Return one expansion of the accumulator recorded in struct VE. */
1933 get_expansion (struct var_to_expand *ve)
1937 if (ve->reuse_expansion == 0)
1940 reg = VEC_index (rtx, ve->var_expansions, ve->reuse_expansion - 1);
1942 if (VEC_length (rtx, ve->var_expansions) == (unsigned) ve->reuse_expansion)
1943 ve->reuse_expansion = 0;
1945 ve->reuse_expansion++;
1951 /* Given INSN replace the uses of the accumulator recorded in VE
1952 with a new register. */
1955 expand_var_during_unrolling (struct var_to_expand *ve, rtx insn)
1958 bool really_new_expansion = false;
1960 set = single_set (insn);
1963 /* Generate a new register only if the expansion limit has not been
1964 reached. Else reuse an already existing expansion. */
1965 if (PARAM_VALUE (PARAM_MAX_VARIABLE_EXPANSIONS) > ve->expansion_count)
1967 really_new_expansion = true;
1968 new_reg = gen_reg_rtx (GET_MODE (ve->reg));
1971 new_reg = get_expansion (ve);
1973 validate_change (insn, &SET_DEST (set), new_reg, 1);
1974 validate_change (insn, &XEXP (SET_SRC (set), 0), new_reg, 1);
1976 if (apply_change_group ())
1977 if (really_new_expansion)
1979 VEC_safe_push (rtx, heap, ve->var_expansions, new_reg);
1980 ve->expansion_count++;
1984 /* Initialize the variable expansions in loop preheader.
1985 Callbacks for htab_traverse. PLACE_P is the loop-preheader
1986 basic block where the initialization of the expansions
1987 should take place. */
1990 insert_var_expansion_initialization (void **slot, void *place_p)
1992 struct var_to_expand *ve = *slot;
1993 basic_block place = (basic_block)place_p;
1994 rtx seq, var, zero_init, insn;
1997 if (VEC_length (rtx, ve->var_expansions) == 0)
2001 if (ve->op == PLUS || ve->op == MINUS)
2002 for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++)
2004 zero_init = CONST0_RTX (GET_MODE (var));
2005 emit_move_insn (var, zero_init);
2007 else if (ve->op == MULT)
2008 for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++)
2010 zero_init = CONST1_RTX (GET_MODE (var));
2011 emit_move_insn (var, zero_init);
2017 insn = BB_HEAD (place);
2018 while (!NOTE_INSN_BASIC_BLOCK_P (insn))
2019 insn = NEXT_INSN (insn);
2021 emit_insn_after (seq, insn);
2022 /* Continue traversing the hash table. */
2026 /* Combine the variable expansions at the loop exit.
2027 Callbacks for htab_traverse. PLACE_P is the loop exit
2028 basic block where the summation of the expansions should
2032 combine_var_copies_in_loop_exit (void **slot, void *place_p)
2034 struct var_to_expand *ve = *slot;
2035 basic_block place = (basic_block)place_p;
2037 rtx expr, seq, var, insn;
2040 if (VEC_length (rtx, ve->var_expansions) == 0)
2044 if (ve->op == PLUS || ve->op == MINUS)
2045 for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++)
2047 sum = simplify_gen_binary (PLUS, GET_MODE (ve->reg),
2050 else if (ve->op == MULT)
2051 for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++)
2053 sum = simplify_gen_binary (MULT, GET_MODE (ve->reg),
2057 expr = force_operand (sum, ve->reg);
2058 if (expr != ve->reg)
2059 emit_move_insn (ve->reg, expr);
2063 insn = BB_HEAD (place);
2064 while (!NOTE_INSN_BASIC_BLOCK_P (insn))
2065 insn = NEXT_INSN (insn);
2067 emit_insn_after (seq, insn);
2069 /* Continue traversing the hash table. */
2073 /* Apply loop optimizations in loop copies using the
2074 data which gathered during the unrolling. Structure
2075 OPT_INFO record that data.
2077 UNROLLING is true if we unrolled (not peeled) the loop.
2078 REWRITE_ORIGINAL_BODY is true if we should also rewrite the original body of
2079 the loop (as it should happen in complete unrolling, but not in ordinary
2080 peeling of the loop). */
2083 apply_opt_in_copies (struct opt_info *opt_info,
2084 unsigned n_copies, bool unrolling,
2085 bool rewrite_original_loop)
2088 basic_block bb, orig_bb;
2089 rtx insn, orig_insn, next;
2090 struct iv_to_split ivts_templ, *ivts;
2091 struct var_to_expand ve_templ, *ves;
2093 /* Sanity check -- we need to put initialization in the original loop
2095 gcc_assert (!unrolling || rewrite_original_loop);
2097 /* Allocate the basic variables (i0). */
2098 if (opt_info->insns_to_split)
2099 htab_traverse (opt_info->insns_to_split, allocate_basic_variable, NULL);
2101 for (i = opt_info->first_new_block; i < (unsigned) last_basic_block; i++)
2103 bb = BASIC_BLOCK (i);
2104 orig_bb = get_bb_original (bb);
2106 /* bb->aux holds position in copy sequence initialized by
2107 duplicate_loop_to_header_edge. */
2108 delta = determine_split_iv_delta ((size_t)bb->aux, n_copies,
2111 orig_insn = BB_HEAD (orig_bb);
2112 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); insn = next)
2114 next = NEXT_INSN (insn);
2118 while (!INSN_P (orig_insn))
2119 orig_insn = NEXT_INSN (orig_insn);
2121 ivts_templ.insn = orig_insn;
2122 ve_templ.insn = orig_insn;
2124 /* Apply splitting iv optimization. */
2125 if (opt_info->insns_to_split)
2127 ivts = htab_find (opt_info->insns_to_split, &ivts_templ);
2131 gcc_assert (GET_CODE (PATTERN (insn))
2132 == GET_CODE (PATTERN (orig_insn)));
2135 insert_base_initialization (ivts, insn);
2136 split_iv (ivts, insn, delta);
2139 /* Apply variable expansion optimization. */
2140 if (unrolling && opt_info->insns_with_var_to_expand)
2142 ves = htab_find (opt_info->insns_with_var_to_expand, &ve_templ);
2145 gcc_assert (GET_CODE (PATTERN (insn))
2146 == GET_CODE (PATTERN (orig_insn)));
2147 expand_var_during_unrolling (ves, insn);
2150 orig_insn = NEXT_INSN (orig_insn);
2154 if (!rewrite_original_loop)
2157 /* Initialize the variable expansions in the loop preheader
2158 and take care of combining them at the loop exit. */
2159 if (opt_info->insns_with_var_to_expand)
2161 htab_traverse (opt_info->insns_with_var_to_expand,
2162 insert_var_expansion_initialization,
2163 opt_info->loop_preheader);
2164 htab_traverse (opt_info->insns_with_var_to_expand,
2165 combine_var_copies_in_loop_exit,
2166 opt_info->loop_exit);
2169 /* Rewrite also the original loop body. Find them as originals of the blocks
2170 in the last copied iteration, i.e. those that have
2171 get_bb_copy (get_bb_original (bb)) == bb. */
2172 for (i = opt_info->first_new_block; i < (unsigned) last_basic_block; i++)
2174 bb = BASIC_BLOCK (i);
2175 orig_bb = get_bb_original (bb);
2176 if (get_bb_copy (orig_bb) != bb)
2179 delta = determine_split_iv_delta (0, n_copies, unrolling);
2180 for (orig_insn = BB_HEAD (orig_bb);
2181 orig_insn != NEXT_INSN (BB_END (bb));
2184 next = NEXT_INSN (orig_insn);
2186 if (!INSN_P (orig_insn))
2189 ivts_templ.insn = orig_insn;
2190 if (opt_info->insns_to_split)
2192 ivts = htab_find (opt_info->insns_to_split, &ivts_templ);
2196 insert_base_initialization (ivts, orig_insn);
2197 split_iv (ivts, orig_insn, delta);
2206 /* Release the data structures used for the variable expansion
2207 optimization. Callbacks for htab_traverse. */
2210 release_var_copies (void **slot, void *data ATTRIBUTE_UNUSED)
2212 struct var_to_expand *ve = *slot;
2214 VEC_free (rtx, heap, ve->var_expansions);
2216 /* Continue traversing the hash table. */
2220 /* Release OPT_INFO. */
2223 free_opt_info (struct opt_info *opt_info)
2225 if (opt_info->insns_to_split)
2226 htab_delete (opt_info->insns_to_split);
2227 if (opt_info->insns_with_var_to_expand)
2229 htab_traverse (opt_info->insns_with_var_to_expand,
2230 release_var_copies, NULL);
2231 htab_delete (opt_info->insns_with_var_to_expand);