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"
38 /* This pass performs loop unrolling and peeling. We only perform these
39 optimizations on innermost loops (with single exception) because
40 the impact on performance is greatest here, and we want to avoid
41 unnecessary code size growth. The gain is caused by greater sequentiality
42 of code, better code to optimize for further passes and in some cases
43 by fewer testings of exit conditions. The main problem is code growth,
44 that impacts performance negatively due to effect of caches.
48 -- complete peeling of once-rolling loops; this is the above mentioned
49 exception, as this causes loop to be cancelled completely and
50 does not cause code growth
51 -- complete peeling of loops that roll (small) constant times.
52 -- simple peeling of first iterations of loops that do not roll much
53 (according to profile feedback)
54 -- unrolling of loops that roll constant times; this is almost always
55 win, as we get rid of exit condition tests.
56 -- unrolling of loops that roll number of times that we can compute
57 in runtime; we also get rid of exit condition tests here, but there
58 is the extra expense for calculating the number of iterations
59 -- simple unrolling of remaining loops; this is performed only if we
60 are asked to, as the gain is questionable in this case and often
61 it may even slow down the code
62 For more detailed descriptions of each of those, see comments at
63 appropriate function below.
65 There is a lot of parameters (defined and described in params.def) that
66 control how much we unroll/peel.
68 ??? A great problem is that we don't have a good way how to determine
69 how many times we should unroll the loop; the experiments I have made
70 showed that this choice may affect performance in order of several %.
73 /* Information about induction variables to split. */
77 rtx insn; /* The insn in that the induction variable occurs. */
78 rtx base_var; /* The variable on that the values in the further
79 iterations are based. */
80 rtx step; /* Step of the induction variable. */
82 unsigned loc[3]; /* Location where the definition of the induction
83 variable occurs in the insn. For example if
84 N_LOC is 2, the expression is located at
85 XEXP (XEXP (single_set, loc[0]), loc[1]). */
89 DEF_VEC_ALLOC_P(rtx,heap);
91 /* Information about accumulators to expand. */
95 rtx insn; /* The insn in that the variable expansion occurs. */
96 rtx reg; /* The accumulator which is expanded. */
97 VEC(rtx,heap) *var_expansions; /* The copies of the accumulator which is expanded. */
98 enum rtx_code op; /* The type of the accumulation - addition, subtraction
100 int expansion_count; /* Count the number of expansions generated so far. */
101 int reuse_expansion; /* The expansion we intend to reuse to expand
102 the accumulator. If REUSE_EXPANSION is 0 reuse
103 the original accumulator. Else use
104 var_expansions[REUSE_EXPANSION - 1]. */
107 /* Information about optimization applied in
108 the unrolled loop. */
112 htab_t insns_to_split; /* A hashtable of insns to split. */
113 htab_t insns_with_var_to_expand; /* A hashtable of insns with accumulators
115 unsigned first_new_block; /* The first basic block that was
117 basic_block loop_exit; /* The loop exit basic block. */
118 basic_block loop_preheader; /* The loop preheader basic block. */
121 static void decide_unrolling_and_peeling (struct loops *, int);
122 static void peel_loops_completely (struct loops *, int);
123 static void decide_peel_simple (struct loop *, int);
124 static void decide_peel_once_rolling (struct loop *, int);
125 static void decide_peel_completely (struct loop *, int);
126 static void decide_unroll_stupid (struct loop *, int);
127 static void decide_unroll_constant_iterations (struct loop *, int);
128 static void decide_unroll_runtime_iterations (struct loop *, int);
129 static void peel_loop_simple (struct loops *, struct loop *);
130 static void peel_loop_completely (struct loops *, struct loop *);
131 static void unroll_loop_stupid (struct loops *, struct loop *);
132 static void unroll_loop_constant_iterations (struct loops *, struct loop *);
133 static void unroll_loop_runtime_iterations (struct loops *, struct loop *);
134 static struct opt_info *analyze_insns_in_loop (struct loop *);
135 static void opt_info_start_duplication (struct opt_info *);
136 static void apply_opt_in_copies (struct opt_info *, unsigned, bool, bool);
137 static void free_opt_info (struct opt_info *);
138 static struct var_to_expand *analyze_insn_to_expand_var (struct loop*, rtx);
139 static bool referenced_in_one_insn_in_loop_p (struct loop *, rtx);
140 static struct iv_to_split *analyze_iv_to_split_insn (rtx);
141 static void expand_var_during_unrolling (struct var_to_expand *, rtx);
142 static int insert_var_expansion_initialization (void **, void *);
143 static int combine_var_copies_in_loop_exit (void **, void *);
144 static int release_var_copies (void **, void *);
145 static rtx get_expansion (struct var_to_expand *);
147 /* Unroll and/or peel (depending on FLAGS) LOOPS. */
149 unroll_and_peel_loops (struct loops *loops, int flags)
151 struct loop *loop, *next;
154 /* First perform complete loop peeling (it is almost surely a win,
155 and affects parameters for further decision a lot). */
156 peel_loops_completely (loops, flags);
158 /* Now decide rest of unrolling and peeling. */
159 decide_unrolling_and_peeling (loops, flags);
161 loop = loops->tree_root;
165 /* Scan the loops, inner ones first. */
166 while (loop != loops->tree_root)
178 /* And perform the appropriate transformations. */
179 switch (loop->lpt_decision.decision)
181 case LPT_PEEL_COMPLETELY:
184 case LPT_PEEL_SIMPLE:
185 peel_loop_simple (loops, loop);
187 case LPT_UNROLL_CONSTANT:
188 unroll_loop_constant_iterations (loops, loop);
190 case LPT_UNROLL_RUNTIME:
191 unroll_loop_runtime_iterations (loops, loop);
193 case LPT_UNROLL_STUPID:
194 unroll_loop_stupid (loops, loop);
204 #ifdef ENABLE_CHECKING
205 verify_dominators (CDI_DOMINATORS);
206 verify_loop_structure (loops);
215 /* Check whether exit of the LOOP is at the end of loop body. */
218 loop_exit_at_end_p (struct loop *loop)
220 struct niter_desc *desc = get_simple_loop_desc (loop);
223 if (desc->in_edge->dest != loop->latch)
226 /* Check that the latch is empty. */
227 FOR_BB_INSNS (loop->latch, insn)
236 /* Check whether to peel LOOPS (depending on FLAGS) completely and do so. */
238 peel_loops_completely (struct loops *loops, int flags)
240 struct loop *loop, *next;
242 loop = loops->tree_root;
246 while (loop != loops->tree_root)
257 loop->lpt_decision.decision = LPT_NONE;
261 "\n;; *** Considering loop %d for complete peeling ***\n",
264 loop->ninsns = num_loop_insns (loop);
266 decide_peel_once_rolling (loop, flags);
267 if (loop->lpt_decision.decision == LPT_NONE)
268 decide_peel_completely (loop, flags);
270 if (loop->lpt_decision.decision == LPT_PEEL_COMPLETELY)
272 peel_loop_completely (loops, loop);
273 #ifdef ENABLE_CHECKING
274 verify_dominators (CDI_DOMINATORS);
275 verify_loop_structure (loops);
282 /* Decide whether unroll or peel LOOPS (depending on FLAGS) and how much. */
284 decide_unrolling_and_peeling (struct loops *loops, int flags)
286 struct loop *loop = loops->tree_root, *next;
291 /* Scan the loops, inner ones first. */
292 while (loop != loops->tree_root)
303 loop->lpt_decision.decision = LPT_NONE;
306 fprintf (dump_file, "\n;; *** Considering loop %d ***\n", loop->num);
308 /* Do not peel cold areas. */
309 if (!maybe_hot_bb_p (loop->header))
312 fprintf (dump_file, ";; Not considering loop, cold area\n");
317 /* Can the loop be manipulated? */
318 if (!can_duplicate_loop_p (loop))
322 ";; Not considering loop, cannot duplicate\n");
327 /* Skip non-innermost loops. */
331 fprintf (dump_file, ";; Not considering loop, is not innermost\n");
336 loop->ninsns = num_loop_insns (loop);
337 loop->av_ninsns = average_num_loop_insns (loop);
339 /* Try transformations one by one in decreasing order of
342 decide_unroll_constant_iterations (loop, flags);
343 if (loop->lpt_decision.decision == LPT_NONE)
344 decide_unroll_runtime_iterations (loop, flags);
345 if (loop->lpt_decision.decision == LPT_NONE)
346 decide_unroll_stupid (loop, flags);
347 if (loop->lpt_decision.decision == LPT_NONE)
348 decide_peel_simple (loop, flags);
354 /* Decide whether the LOOP is once rolling and suitable for complete
357 decide_peel_once_rolling (struct loop *loop, int flags ATTRIBUTE_UNUSED)
359 struct niter_desc *desc;
362 fprintf (dump_file, "\n;; Considering peeling once rolling loop\n");
364 /* Is the loop small enough? */
365 if ((unsigned) PARAM_VALUE (PARAM_MAX_ONCE_PEELED_INSNS) < loop->ninsns)
368 fprintf (dump_file, ";; Not considering loop, is too big\n");
372 /* Check for simple loops. */
373 desc = get_simple_loop_desc (loop);
375 /* Check number of iterations. */
384 ";; Unable to prove that the loop rolls exactly once\n");
390 fprintf (dump_file, ";; Decided to peel exactly once rolling loop\n");
391 loop->lpt_decision.decision = LPT_PEEL_COMPLETELY;
394 /* Decide whether the LOOP is suitable for complete peeling. */
396 decide_peel_completely (struct loop *loop, int flags ATTRIBUTE_UNUSED)
399 struct niter_desc *desc;
402 fprintf (dump_file, "\n;; Considering peeling completely\n");
404 /* Skip non-innermost loops. */
408 fprintf (dump_file, ";; Not considering loop, is not innermost\n");
412 /* Do not peel cold areas. */
413 if (!maybe_hot_bb_p (loop->header))
416 fprintf (dump_file, ";; Not considering loop, cold area\n");
420 /* Can the loop be manipulated? */
421 if (!can_duplicate_loop_p (loop))
425 ";; Not considering loop, cannot duplicate\n");
429 /* npeel = number of iterations to peel. */
430 npeel = PARAM_VALUE (PARAM_MAX_COMPLETELY_PEELED_INSNS) / loop->ninsns;
431 if (npeel > (unsigned) PARAM_VALUE (PARAM_MAX_COMPLETELY_PEEL_TIMES))
432 npeel = PARAM_VALUE (PARAM_MAX_COMPLETELY_PEEL_TIMES);
434 /* Is the loop small enough? */
438 fprintf (dump_file, ";; Not considering loop, is too big\n");
442 /* Check for simple loops. */
443 desc = get_simple_loop_desc (loop);
445 /* Check number of iterations. */
453 ";; Unable to prove that the loop iterates constant times\n");
457 if (desc->niter > npeel - 1)
462 ";; Not peeling loop completely, rolls too much (");
463 fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC, desc->niter);
464 fprintf (dump_file, " iterations > %d [maximum peelings])\n", npeel);
471 fprintf (dump_file, ";; Decided to peel loop completely\n");
472 loop->lpt_decision.decision = LPT_PEEL_COMPLETELY;
475 /* Peel all iterations of LOOP, remove exit edges and cancel the loop
476 completely. The transformation done:
478 for (i = 0; i < 4; i++)
490 peel_loop_completely (struct loops *loops, struct loop *loop)
493 unsigned HOST_WIDE_INT npeel;
494 unsigned n_remove_edges, i;
495 edge *remove_edges, ein;
496 struct niter_desc *desc = get_simple_loop_desc (loop);
497 struct opt_info *opt_info = NULL;
505 wont_exit = sbitmap_alloc (npeel + 1);
506 sbitmap_ones (wont_exit);
507 RESET_BIT (wont_exit, 0);
508 if (desc->noloop_assumptions)
509 RESET_BIT (wont_exit, 1);
511 remove_edges = xcalloc (npeel, sizeof (edge));
514 if (flag_split_ivs_in_unroller)
515 opt_info = analyze_insns_in_loop (loop);
517 opt_info_start_duplication (opt_info);
518 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
520 wont_exit, desc->out_edge,
521 remove_edges, &n_remove_edges,
522 DLTHE_FLAG_UPDATE_FREQ
524 ? DLTHE_RECORD_COPY_NUMBER : 0));
531 apply_opt_in_copies (opt_info, npeel, false, true);
532 free_opt_info (opt_info);
535 /* Remove the exit edges. */
536 for (i = 0; i < n_remove_edges; i++)
537 remove_path (loops, remove_edges[i]);
542 free_simple_loop_desc (loop);
544 /* Now remove the unreachable part of the last iteration and cancel
546 remove_path (loops, ein);
549 fprintf (dump_file, ";; Peeled loop completely, %d times\n", (int) npeel);
552 /* Decide whether to unroll LOOP iterating constant number of times
556 decide_unroll_constant_iterations (struct loop *loop, int flags)
558 unsigned nunroll, nunroll_by_av, best_copies, best_unroll = 0, n_copies, i;
559 struct niter_desc *desc;
561 if (!(flags & UAP_UNROLL))
563 /* We were not asked to, just return back silently. */
569 "\n;; Considering unrolling loop with constant "
570 "number of iterations\n");
572 /* nunroll = total number of copies of the original loop body in
573 unrolled loop (i.e. if it is 2, we have to duplicate loop body once. */
574 nunroll = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / loop->ninsns;
576 = PARAM_VALUE (PARAM_MAX_AVERAGE_UNROLLED_INSNS) / loop->av_ninsns;
577 if (nunroll > nunroll_by_av)
578 nunroll = nunroll_by_av;
579 if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES))
580 nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES);
582 /* Skip big loops. */
586 fprintf (dump_file, ";; Not considering loop, is too big\n");
590 /* Check for simple loops. */
591 desc = get_simple_loop_desc (loop);
593 /* Check number of iterations. */
594 if (!desc->simple_p || !desc->const_iter || desc->assumptions)
598 ";; Unable to prove that the loop iterates constant times\n");
602 /* Check whether the loop rolls enough to consider. */
603 if (desc->niter < 2 * nunroll)
606 fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n");
610 /* Success; now compute number of iterations to unroll. We alter
611 nunroll so that as few as possible copies of loop body are
612 necessary, while still not decreasing the number of unrollings
613 too much (at most by 1). */
614 best_copies = 2 * nunroll + 10;
617 if (i - 1 >= desc->niter)
620 for (; i >= nunroll - 1; i--)
622 unsigned exit_mod = desc->niter % (i + 1);
624 if (!loop_exit_at_end_p (loop))
625 n_copies = exit_mod + i + 1;
626 else if (exit_mod != (unsigned) i
627 || desc->noloop_assumptions != NULL_RTX)
628 n_copies = exit_mod + i + 2;
632 if (n_copies < best_copies)
634 best_copies = n_copies;
640 fprintf (dump_file, ";; max_unroll %d (%d copies, initial %d).\n",
641 best_unroll + 1, best_copies, nunroll);
643 loop->lpt_decision.decision = LPT_UNROLL_CONSTANT;
644 loop->lpt_decision.times = best_unroll;
648 ";; Decided to unroll the constant times rolling loop, %d times.\n",
649 loop->lpt_decision.times);
652 /* Unroll LOOP with constant number of iterations LOOP->LPT_DECISION.TIMES + 1
653 times. The transformation does this:
655 for (i = 0; i < 102; i++)
672 unroll_loop_constant_iterations (struct loops *loops, struct loop *loop)
674 unsigned HOST_WIDE_INT niter;
677 unsigned n_remove_edges, i;
679 unsigned max_unroll = loop->lpt_decision.times;
680 struct niter_desc *desc = get_simple_loop_desc (loop);
681 bool exit_at_end = loop_exit_at_end_p (loop);
682 struct opt_info *opt_info = NULL;
687 /* Should not get here (such loop should be peeled instead). */
688 gcc_assert (niter > max_unroll + 1);
690 exit_mod = niter % (max_unroll + 1);
692 wont_exit = sbitmap_alloc (max_unroll + 1);
693 sbitmap_ones (wont_exit);
695 remove_edges = xcalloc (max_unroll + exit_mod + 1, sizeof (edge));
697 if (flag_split_ivs_in_unroller
698 || flag_variable_expansion_in_unroller)
699 opt_info = analyze_insns_in_loop (loop);
703 /* The exit is not at the end of the loop; leave exit test
704 in the first copy, so that the loops that start with test
705 of exit condition have continuous body after unrolling. */
708 fprintf (dump_file, ";; Condition on beginning of loop.\n");
710 /* Peel exit_mod iterations. */
711 RESET_BIT (wont_exit, 0);
712 if (desc->noloop_assumptions)
713 RESET_BIT (wont_exit, 1);
717 opt_info_start_duplication (opt_info);
718 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
720 wont_exit, desc->out_edge,
721 remove_edges, &n_remove_edges,
722 DLTHE_FLAG_UPDATE_FREQ
723 | (opt_info && exit_mod > 1
724 ? DLTHE_RECORD_COPY_NUMBER
728 if (opt_info && exit_mod > 1)
729 apply_opt_in_copies (opt_info, exit_mod, false, false);
731 desc->noloop_assumptions = NULL_RTX;
732 desc->niter -= exit_mod;
733 desc->niter_max -= exit_mod;
736 SET_BIT (wont_exit, 1);
740 /* Leave exit test in last copy, for the same reason as above if
741 the loop tests the condition at the end of loop body. */
744 fprintf (dump_file, ";; Condition on end of loop.\n");
746 /* We know that niter >= max_unroll + 2; so we do not need to care of
747 case when we would exit before reaching the loop. So just peel
748 exit_mod + 1 iterations. */
749 if (exit_mod != max_unroll
750 || desc->noloop_assumptions)
752 RESET_BIT (wont_exit, 0);
753 if (desc->noloop_assumptions)
754 RESET_BIT (wont_exit, 1);
756 opt_info_start_duplication (opt_info);
757 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
759 wont_exit, desc->out_edge,
760 remove_edges, &n_remove_edges,
761 DLTHE_FLAG_UPDATE_FREQ
762 | (opt_info && exit_mod > 0
763 ? DLTHE_RECORD_COPY_NUMBER
767 if (opt_info && exit_mod > 0)
768 apply_opt_in_copies (opt_info, exit_mod + 1, false, false);
770 desc->niter -= exit_mod + 1;
771 desc->niter_max -= exit_mod + 1;
772 desc->noloop_assumptions = NULL_RTX;
774 SET_BIT (wont_exit, 0);
775 SET_BIT (wont_exit, 1);
778 RESET_BIT (wont_exit, max_unroll);
781 /* Now unroll the loop. */
783 opt_info_start_duplication (opt_info);
784 ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop),
786 wont_exit, desc->out_edge,
787 remove_edges, &n_remove_edges,
788 DLTHE_FLAG_UPDATE_FREQ
790 ? DLTHE_RECORD_COPY_NUMBER
796 apply_opt_in_copies (opt_info, max_unroll, true, true);
797 free_opt_info (opt_info);
804 basic_block exit_block = get_bb_copy (desc->in_edge->src);
805 /* Find a new in and out edge; they are in the last copy we have made. */
807 if (EDGE_SUCC (exit_block, 0)->dest == desc->out_edge->dest)
809 desc->out_edge = EDGE_SUCC (exit_block, 0);
810 desc->in_edge = EDGE_SUCC (exit_block, 1);
814 desc->out_edge = EDGE_SUCC (exit_block, 1);
815 desc->in_edge = EDGE_SUCC (exit_block, 0);
819 desc->niter /= max_unroll + 1;
820 desc->niter_max /= max_unroll + 1;
821 desc->niter_expr = GEN_INT (desc->niter);
823 /* Remove the edges. */
824 for (i = 0; i < n_remove_edges; i++)
825 remove_path (loops, remove_edges[i]);
830 ";; Unrolled loop %d times, constant # of iterations %i insns\n",
831 max_unroll, num_loop_insns (loop));
834 /* Decide whether to unroll LOOP iterating runtime computable number of times
837 decide_unroll_runtime_iterations (struct loop *loop, int flags)
839 unsigned nunroll, nunroll_by_av, i;
840 struct niter_desc *desc;
842 if (!(flags & UAP_UNROLL))
844 /* We were not asked to, just return back silently. */
850 "\n;; Considering unrolling loop with runtime "
851 "computable number of iterations\n");
853 /* nunroll = total number of copies of the original loop body in
854 unrolled loop (i.e. if it is 2, we have to duplicate loop body once. */
855 nunroll = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / loop->ninsns;
856 nunroll_by_av = PARAM_VALUE (PARAM_MAX_AVERAGE_UNROLLED_INSNS) / loop->av_ninsns;
857 if (nunroll > nunroll_by_av)
858 nunroll = nunroll_by_av;
859 if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES))
860 nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES);
862 /* Skip big loops. */
866 fprintf (dump_file, ";; Not considering loop, is too big\n");
870 /* Check for simple loops. */
871 desc = get_simple_loop_desc (loop);
873 /* Check simpleness. */
874 if (!desc->simple_p || desc->assumptions)
878 ";; Unable to prove that the number of iterations "
879 "can be counted in runtime\n");
883 if (desc->const_iter)
886 fprintf (dump_file, ";; Loop iterates constant times\n");
890 /* If we have profile feedback, check whether the loop rolls. */
891 if (loop->header->count && expected_loop_iterations (loop) < 2 * nunroll)
894 fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n");
898 /* Success; now force nunroll to be power of 2, as we are unable to
899 cope with overflows in computation of number of iterations. */
900 for (i = 1; 2 * i <= nunroll; i *= 2)
903 loop->lpt_decision.decision = LPT_UNROLL_RUNTIME;
904 loop->lpt_decision.times = i - 1;
908 ";; Decided to unroll the runtime computable "
909 "times rolling loop, %d times.\n",
910 loop->lpt_decision.times);
913 /* Unroll LOOP for that we are able to count number of iterations in runtime
914 LOOP->LPT_DECISION.TIMES + 1 times. The transformation does this (with some
915 extra care for case n < 0):
917 for (i = 0; i < n; i++)
945 unroll_loop_runtime_iterations (struct loops *loops, struct loop *loop)
947 rtx old_niter, niter, init_code, branch_code, tmp;
949 basic_block preheader, *body, *dom_bbs, swtch, ezc_swtch;
953 unsigned n_peel, n_remove_edges;
954 edge *remove_edges, e;
955 bool extra_zero_check, last_may_exit;
956 unsigned max_unroll = loop->lpt_decision.times;
957 struct niter_desc *desc = get_simple_loop_desc (loop);
958 bool exit_at_end = loop_exit_at_end_p (loop);
959 struct opt_info *opt_info = NULL;
962 if (flag_split_ivs_in_unroller
963 || flag_variable_expansion_in_unroller)
964 opt_info = analyze_insns_in_loop (loop);
966 /* Remember blocks whose dominators will have to be updated. */
967 dom_bbs = xcalloc (n_basic_blocks, sizeof (basic_block));
970 body = get_loop_body (loop);
971 for (i = 0; i < loop->num_nodes; i++)
976 nldom = get_dominated_by (CDI_DOMINATORS, body[i], &ldom);
977 for (j = 0; j < nldom; j++)
978 if (!flow_bb_inside_loop_p (loop, ldom[j]))
979 dom_bbs[n_dom_bbs++] = ldom[j];
987 /* Leave exit in first copy (for explanation why see comment in
988 unroll_loop_constant_iterations). */
990 n_peel = max_unroll - 1;
991 extra_zero_check = true;
992 last_may_exit = false;
996 /* Leave exit in last copy (for explanation why see comment in
997 unroll_loop_constant_iterations). */
998 may_exit_copy = max_unroll;
1000 extra_zero_check = false;
1001 last_may_exit = true;
1004 /* Get expression for number of iterations. */
1006 old_niter = niter = gen_reg_rtx (desc->mode);
1007 tmp = force_operand (copy_rtx (desc->niter_expr), niter);
1009 emit_move_insn (niter, tmp);
1011 /* Count modulo by ANDing it with max_unroll; we use the fact that
1012 the number of unrollings is a power of two, and thus this is correct
1013 even if there is overflow in the computation. */
1014 niter = expand_simple_binop (desc->mode, AND,
1016 GEN_INT (max_unroll),
1017 NULL_RTX, 0, OPTAB_LIB_WIDEN);
1019 init_code = get_insns ();
1022 /* Precondition the loop. */
1023 loop_split_edge_with (loop_preheader_edge (loop), init_code);
1025 remove_edges = xcalloc (max_unroll + n_peel + 1, sizeof (edge));
1028 wont_exit = sbitmap_alloc (max_unroll + 2);
1030 /* Peel the first copy of loop body (almost always we must leave exit test
1031 here; the only exception is when we have extra zero check and the number
1032 of iterations is reliable. Also record the place of (possible) extra
1034 sbitmap_zero (wont_exit);
1035 if (extra_zero_check
1036 && !desc->noloop_assumptions)
1037 SET_BIT (wont_exit, 1);
1038 ezc_swtch = loop_preheader_edge (loop)->src;
1039 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
1041 wont_exit, desc->out_edge,
1042 remove_edges, &n_remove_edges,
1043 DLTHE_FLAG_UPDATE_FREQ);
1046 /* Record the place where switch will be built for preconditioning. */
1047 swtch = loop_split_edge_with (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 = loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX);
1068 branch_code = compare_and_jump_seq (copy_rtx (niter), GEN_INT (j), EQ,
1069 block_label (preheader), p,
1072 swtch = loop_split_edge_with (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 = loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX);
1086 branch_code = compare_and_jump_seq (copy_rtx (niter), const0_rtx, EQ,
1087 block_label (preheader), p,
1090 swtch = loop_split_edge_with (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));
1172 /* Decide whether to simply peel LOOP and how much. */
1174 decide_peel_simple (struct loop *loop, int flags)
1177 struct niter_desc *desc;
1179 if (!(flags & UAP_PEEL))
1181 /* We were not asked to, just return back silently. */
1186 fprintf (dump_file, "\n;; Considering simply peeling loop\n");
1188 /* npeel = number of iterations to peel. */
1189 npeel = PARAM_VALUE (PARAM_MAX_PEELED_INSNS) / loop->ninsns;
1190 if (npeel > (unsigned) PARAM_VALUE (PARAM_MAX_PEEL_TIMES))
1191 npeel = PARAM_VALUE (PARAM_MAX_PEEL_TIMES);
1193 /* Skip big loops. */
1197 fprintf (dump_file, ";; Not considering loop, is too big\n");
1201 /* Check for simple loops. */
1202 desc = get_simple_loop_desc (loop);
1204 /* Check number of iterations. */
1205 if (desc->simple_p && !desc->assumptions && desc->const_iter)
1208 fprintf (dump_file, ";; Loop iterates constant times\n");
1212 /* Do not simply peel loops with branches inside -- it increases number
1214 if (num_loop_branches (loop) > 1)
1217 fprintf (dump_file, ";; Not peeling, contains branches\n");
1221 if (loop->header->count)
1223 unsigned niter = expected_loop_iterations (loop);
1224 if (niter + 1 > npeel)
1228 fprintf (dump_file, ";; Not peeling loop, rolls too much (");
1229 fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC,
1230 (HOST_WIDEST_INT) (niter + 1));
1231 fprintf (dump_file, " iterations > %d [maximum peelings])\n",
1240 /* For now we have no good heuristics to decide whether loop peeling
1241 will be effective, so disable it. */
1244 ";; Not peeling loop, no evidence it will be profitable\n");
1249 loop->lpt_decision.decision = LPT_PEEL_SIMPLE;
1250 loop->lpt_decision.times = npeel;
1253 fprintf (dump_file, ";; Decided to simply peel the loop, %d times.\n",
1254 loop->lpt_decision.times);
1257 /* Peel a LOOP LOOP->LPT_DECISION.TIMES times. The transformation:
1263 if (!cond) goto end;
1265 if (!cond) goto end;
1272 peel_loop_simple (struct loops *loops, struct loop *loop)
1275 unsigned npeel = loop->lpt_decision.times;
1276 struct niter_desc *desc = get_simple_loop_desc (loop);
1277 struct opt_info *opt_info = NULL;
1280 if (flag_split_ivs_in_unroller && npeel > 1)
1281 opt_info = analyze_insns_in_loop (loop);
1283 wont_exit = sbitmap_alloc (npeel + 1);
1284 sbitmap_zero (wont_exit);
1286 opt_info_start_duplication (opt_info);
1288 ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
1289 loops, npeel, wont_exit,
1291 NULL, DLTHE_FLAG_UPDATE_FREQ
1293 ? DLTHE_RECORD_COPY_NUMBER
1301 apply_opt_in_copies (opt_info, npeel, false, false);
1302 free_opt_info (opt_info);
1307 if (desc->const_iter)
1309 desc->niter -= npeel;
1310 desc->niter_expr = GEN_INT (desc->niter);
1311 desc->noloop_assumptions = NULL_RTX;
1315 /* We cannot just update niter_expr, as its value might be clobbered
1316 inside loop. We could handle this by counting the number into
1317 temporary just like we do in runtime unrolling, but it does not
1319 free_simple_loop_desc (loop);
1323 fprintf (dump_file, ";; Peeling loop %d times\n", npeel);
1326 /* Decide whether to unroll LOOP stupidly and how much. */
1328 decide_unroll_stupid (struct loop *loop, int flags)
1330 unsigned nunroll, nunroll_by_av, i;
1331 struct niter_desc *desc;
1333 if (!(flags & UAP_UNROLL_ALL))
1335 /* We were not asked to, just return back silently. */
1340 fprintf (dump_file, "\n;; Considering unrolling loop stupidly\n");
1342 /* nunroll = total number of copies of the original loop body in
1343 unrolled loop (i.e. if it is 2, we have to duplicate loop body once. */
1344 nunroll = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / loop->ninsns;
1346 = PARAM_VALUE (PARAM_MAX_AVERAGE_UNROLLED_INSNS) / loop->av_ninsns;
1347 if (nunroll > nunroll_by_av)
1348 nunroll = nunroll_by_av;
1349 if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES))
1350 nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES);
1352 /* Skip big loops. */
1356 fprintf (dump_file, ";; Not considering loop, is too big\n");
1360 /* Check for simple loops. */
1361 desc = get_simple_loop_desc (loop);
1363 /* Check simpleness. */
1364 if (desc->simple_p && !desc->assumptions)
1367 fprintf (dump_file, ";; The loop is simple\n");
1371 /* Do not unroll loops with branches inside -- it increases number
1373 if (num_loop_branches (loop) > 1)
1376 fprintf (dump_file, ";; Not unrolling, contains branches\n");
1380 /* If we have profile feedback, check whether the loop rolls. */
1381 if (loop->header->count
1382 && expected_loop_iterations (loop) < 2 * nunroll)
1385 fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n");
1389 /* Success. Now force nunroll to be power of 2, as it seems that this
1390 improves results (partially because of better alignments, partially
1391 because of some dark magic). */
1392 for (i = 1; 2 * i <= nunroll; i *= 2)
1395 loop->lpt_decision.decision = LPT_UNROLL_STUPID;
1396 loop->lpt_decision.times = i - 1;
1400 ";; Decided to unroll the loop stupidly, %d times.\n",
1401 loop->lpt_decision.times);
1404 /* Unroll a LOOP LOOP->LPT_DECISION.TIMES times. The transformation:
1422 unroll_loop_stupid (struct loops *loops, struct loop *loop)
1425 unsigned nunroll = loop->lpt_decision.times;
1426 struct niter_desc *desc = get_simple_loop_desc (loop);
1427 struct opt_info *opt_info = NULL;
1430 if (flag_split_ivs_in_unroller
1431 || flag_variable_expansion_in_unroller)
1432 opt_info = analyze_insns_in_loop (loop);
1435 wont_exit = sbitmap_alloc (nunroll + 1);
1436 sbitmap_zero (wont_exit);
1437 opt_info_start_duplication (opt_info);
1439 ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop),
1440 loops, nunroll, wont_exit,
1442 DLTHE_FLAG_UPDATE_FREQ
1444 ? DLTHE_RECORD_COPY_NUMBER
1450 apply_opt_in_copies (opt_info, nunroll, true, true);
1451 free_opt_info (opt_info);
1458 /* We indeed may get here provided that there are nontrivial assumptions
1459 for a loop to be really simple. We could update the counts, but the
1460 problem is that we are unable to decide which exit will be taken
1461 (not really true in case the number of iterations is constant,
1462 but noone will do anything with this information, so we do not
1464 desc->simple_p = false;
1468 fprintf (dump_file, ";; Unrolled loop %d times, %i insns\n",
1469 nunroll, num_loop_insns (loop));
1472 /* A hash function for information about insns to split. */
1475 si_info_hash (const void *ivts)
1477 return htab_hash_pointer (((struct iv_to_split *) ivts)->insn);
1480 /* An equality functions for information about insns to split. */
1483 si_info_eq (const void *ivts1, const void *ivts2)
1485 const struct iv_to_split *i1 = ivts1;
1486 const struct iv_to_split *i2 = ivts2;
1488 return i1->insn == i2->insn;
1491 /* Return a hash for VES, which is really a "var_to_expand *". */
1494 ve_info_hash (const void *ves)
1496 return htab_hash_pointer (((struct var_to_expand *) ves)->insn);
1499 /* Return true if IVTS1 and IVTS2 (which are really both of type
1500 "var_to_expand *") refer to the same instruction. */
1503 ve_info_eq (const void *ivts1, const void *ivts2)
1505 const struct var_to_expand *i1 = ivts1;
1506 const struct var_to_expand *i2 = ivts2;
1508 return i1->insn == i2->insn;
1511 /* Returns true if REG is referenced in one insn in LOOP. */
1514 referenced_in_one_insn_in_loop_p (struct loop *loop, rtx reg)
1516 basic_block *body, bb;
1521 body = get_loop_body (loop);
1522 for (i = 0; i < loop->num_nodes; i++)
1526 FOR_BB_INSNS (bb, insn)
1528 if (rtx_referenced_p (reg, insn))
1532 return (count_ref == 1);
1535 /* Determine whether INSN contains an accumulator
1536 which can be expanded into separate copies,
1537 one for each copy of the LOOP body.
1539 for (i = 0 ; i < n; i++)
1553 Return NULL if INSN contains no opportunity for expansion of accumulator.
1554 Otherwise, allocate a VAR_TO_EXPAND structure, fill it with the relevant
1555 information and return a pointer to it.
1558 static struct var_to_expand *
1559 analyze_insn_to_expand_var (struct loop *loop, rtx insn)
1561 rtx set, dest, src, op1;
1562 struct var_to_expand *ves;
1563 enum machine_mode mode1, mode2;
1565 set = single_set (insn);
1569 dest = SET_DEST (set);
1570 src = SET_SRC (set);
1572 if (GET_CODE (src) != PLUS
1573 && GET_CODE (src) != MINUS
1574 && GET_CODE (src) != MULT)
1580 op1 = XEXP (src, 0);
1583 && !(GET_CODE (dest) == SUBREG
1584 && REG_P (SUBREG_REG (dest))))
1587 if (!rtx_equal_p (dest, op1))
1590 if (!referenced_in_one_insn_in_loop_p (loop, dest))
1593 if (rtx_referenced_p (dest, XEXP (src, 1)))
1596 mode1 = GET_MODE (dest);
1597 mode2 = GET_MODE (XEXP (src, 1));
1598 if ((FLOAT_MODE_P (mode1)
1599 || FLOAT_MODE_P (mode2))
1600 && !flag_unsafe_math_optimizations)
1603 /* Record the accumulator to expand. */
1604 ves = xmalloc (sizeof (struct var_to_expand));
1606 ves->var_expansions = VEC_alloc (rtx, heap, 1);
1607 ves->reg = copy_rtx (dest);
1608 ves->op = GET_CODE (src);
1609 ves->expansion_count = 0;
1610 ves->reuse_expansion = 0;
1614 /* Determine whether there is an induction variable in INSN that
1615 we would like to split during unrolling.
1635 Return NULL if INSN contains no interesting IVs. Otherwise, allocate
1636 an IV_TO_SPLIT structure, fill it with the relevant information and return a
1639 static struct iv_to_split *
1640 analyze_iv_to_split_insn (rtx insn)
1644 struct iv_to_split *ivts;
1647 /* For now we just split the basic induction variables. Later this may be
1648 extended for example by selecting also addresses of memory references. */
1649 set = single_set (insn);
1653 dest = SET_DEST (set);
1657 if (!biv_p (insn, dest))
1660 ok = iv_analyze (insn, dest, &iv);
1663 if (iv.step == const0_rtx
1664 || iv.mode != iv.extend_mode)
1667 /* Record the insn to split. */
1668 ivts = xmalloc (sizeof (struct iv_to_split));
1670 ivts->base_var = NULL_RTX;
1671 ivts->step = iv.step;
1678 /* Determines which of insns in LOOP can be optimized.
1679 Return a OPT_INFO struct with the relevant hash tables filled
1680 with all insns to be optimized. The FIRST_NEW_BLOCK field
1681 is undefined for the return value. */
1683 static struct opt_info *
1684 analyze_insns_in_loop (struct loop *loop)
1686 basic_block *body, bb;
1687 unsigned i, num_edges = 0;
1688 struct opt_info *opt_info = xcalloc (1, sizeof (struct opt_info));
1690 struct iv_to_split *ivts = NULL;
1691 struct var_to_expand *ves = NULL;
1694 edge *edges = get_loop_exit_edges (loop, &num_edges);
1695 bool can_apply = false;
1697 iv_analysis_loop_init (loop);
1699 body = get_loop_body (loop);
1701 if (flag_split_ivs_in_unroller)
1702 opt_info->insns_to_split = htab_create (5 * loop->num_nodes,
1703 si_info_hash, si_info_eq, free);
1705 /* Record the loop exit bb and loop preheader before the unrolling. */
1706 if (!loop_preheader_edge (loop)->src)
1708 loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX);
1709 opt_info->loop_preheader = loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX);
1712 opt_info->loop_preheader = loop_preheader_edge (loop)->src;
1715 && !(edges[0]->flags & EDGE_COMPLEX))
1717 opt_info->loop_exit = loop_split_edge_with (edges[0], NULL_RTX);
1721 if (flag_variable_expansion_in_unroller
1723 opt_info->insns_with_var_to_expand = htab_create (5 * loop->num_nodes,
1724 ve_info_hash, ve_info_eq, free);
1726 for (i = 0; i < loop->num_nodes; i++)
1729 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
1732 FOR_BB_INSNS (bb, insn)
1737 if (opt_info->insns_to_split)
1738 ivts = analyze_iv_to_split_insn (insn);
1742 slot1 = htab_find_slot (opt_info->insns_to_split, ivts, INSERT);
1747 if (opt_info->insns_with_var_to_expand)
1748 ves = analyze_insn_to_expand_var (loop, insn);
1752 slot2 = htab_find_slot (opt_info->insns_with_var_to_expand, ves, INSERT);
1763 /* Called just before loop duplication. Records start of duplicated area
1767 opt_info_start_duplication (struct opt_info *opt_info)
1770 opt_info->first_new_block = last_basic_block;
1773 /* Determine the number of iterations between initialization of the base
1774 variable and the current copy (N_COPY). N_COPIES is the total number
1775 of newly created copies. UNROLLING is true if we are unrolling
1776 (not peeling) the loop. */
1779 determine_split_iv_delta (unsigned n_copy, unsigned n_copies, bool unrolling)
1783 /* If we are unrolling, initialization is done in the original loop
1789 /* If we are peeling, the copy in that the initialization occurs has
1790 number 1. The original loop (number 0) is the last. */
1798 /* Locate in EXPR the expression corresponding to the location recorded
1799 in IVTS, and return a pointer to the RTX for this location. */
1802 get_ivts_expr (rtx expr, struct iv_to_split *ivts)
1807 for (i = 0; i < ivts->n_loc; i++)
1808 ret = &XEXP (*ret, ivts->loc[i]);
1813 /* Allocate basic variable for the induction variable chain. Callback for
1817 allocate_basic_variable (void **slot, void *data ATTRIBUTE_UNUSED)
1819 struct iv_to_split *ivts = *slot;
1820 rtx expr = *get_ivts_expr (single_set (ivts->insn), ivts);
1822 ivts->base_var = gen_reg_rtx (GET_MODE (expr));
1827 /* Insert initialization of basic variable of IVTS before INSN, taking
1828 the initial value from INSN. */
1831 insert_base_initialization (struct iv_to_split *ivts, rtx insn)
1833 rtx expr = copy_rtx (*get_ivts_expr (single_set (insn), ivts));
1837 expr = force_operand (expr, ivts->base_var);
1838 if (expr != ivts->base_var)
1839 emit_move_insn (ivts->base_var, expr);
1843 emit_insn_before (seq, insn);
1846 /* Replace the use of induction variable described in IVTS in INSN
1847 by base variable + DELTA * step. */
1850 split_iv (struct iv_to_split *ivts, rtx insn, unsigned delta)
1852 rtx expr, *loc, seq, incr, var;
1853 enum machine_mode mode = GET_MODE (ivts->base_var);
1856 /* Construct base + DELTA * step. */
1858 expr = ivts->base_var;
1861 incr = simplify_gen_binary (MULT, mode,
1862 ivts->step, gen_int_mode (delta, mode));
1863 expr = simplify_gen_binary (PLUS, GET_MODE (ivts->base_var),
1864 ivts->base_var, incr);
1867 /* Figure out where to do the replacement. */
1868 loc = get_ivts_expr (single_set (insn), ivts);
1870 /* If we can make the replacement right away, we're done. */
1871 if (validate_change (insn, loc, expr, 0))
1874 /* Otherwise, force EXPR into a register and try again. */
1876 var = gen_reg_rtx (mode);
1877 expr = force_operand (expr, var);
1879 emit_move_insn (var, expr);
1882 emit_insn_before (seq, insn);
1884 if (validate_change (insn, loc, var, 0))
1887 /* The last chance. Try recreating the assignment in insn
1888 completely from scratch. */
1889 set = single_set (insn);
1894 src = copy_rtx (SET_SRC (set));
1895 dest = copy_rtx (SET_DEST (set));
1896 src = force_operand (src, dest);
1898 emit_move_insn (dest, src);
1902 emit_insn_before (seq, insn);
1907 /* Return one expansion of the accumulator recorded in struct VE. */
1910 get_expansion (struct var_to_expand *ve)
1914 if (ve->reuse_expansion == 0)
1917 reg = VEC_index (rtx, ve->var_expansions, ve->reuse_expansion - 1);
1919 if (VEC_length (rtx, ve->var_expansions) == (unsigned) ve->reuse_expansion)
1920 ve->reuse_expansion = 0;
1922 ve->reuse_expansion++;
1928 /* Given INSN replace the uses of the accumulator recorded in VE
1929 with a new register. */
1932 expand_var_during_unrolling (struct var_to_expand *ve, rtx insn)
1935 bool really_new_expansion = false;
1937 set = single_set (insn);
1940 /* Generate a new register only if the expansion limit has not been
1941 reached. Else reuse an already existing expansion. */
1942 if (PARAM_VALUE (PARAM_MAX_VARIABLE_EXPANSIONS) > ve->expansion_count)
1944 really_new_expansion = true;
1945 new_reg = gen_reg_rtx (GET_MODE (ve->reg));
1948 new_reg = get_expansion (ve);
1950 validate_change (insn, &SET_DEST (set), new_reg, 1);
1951 validate_change (insn, &XEXP (SET_SRC (set), 0), new_reg, 1);
1953 if (apply_change_group ())
1954 if (really_new_expansion)
1956 VEC_safe_push (rtx, heap, ve->var_expansions, new_reg);
1957 ve->expansion_count++;
1961 /* Initialize the variable expansions in loop preheader.
1962 Callbacks for htab_traverse. PLACE_P is the loop-preheader
1963 basic block where the initialization of the expansions
1964 should take place. */
1967 insert_var_expansion_initialization (void **slot, void *place_p)
1969 struct var_to_expand *ve = *slot;
1970 basic_block place = (basic_block)place_p;
1971 rtx seq, var, zero_init, insn;
1974 if (VEC_length (rtx, ve->var_expansions) == 0)
1978 if (ve->op == PLUS || ve->op == MINUS)
1979 for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++)
1981 zero_init = CONST0_RTX (GET_MODE (var));
1982 emit_move_insn (var, zero_init);
1984 else if (ve->op == MULT)
1985 for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++)
1987 zero_init = CONST1_RTX (GET_MODE (var));
1988 emit_move_insn (var, zero_init);
1994 insn = BB_HEAD (place);
1995 while (!NOTE_INSN_BASIC_BLOCK_P (insn))
1996 insn = NEXT_INSN (insn);
1998 emit_insn_after (seq, insn);
1999 /* Continue traversing the hash table. */
2003 /* Combine the variable expansions at the loop exit.
2004 Callbacks for htab_traverse. PLACE_P is the loop exit
2005 basic block where the summation of the expansions should
2009 combine_var_copies_in_loop_exit (void **slot, void *place_p)
2011 struct var_to_expand *ve = *slot;
2012 basic_block place = (basic_block)place_p;
2014 rtx expr, seq, var, insn;
2017 if (VEC_length (rtx, ve->var_expansions) == 0)
2021 if (ve->op == PLUS || ve->op == MINUS)
2022 for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++)
2024 sum = simplify_gen_binary (PLUS, GET_MODE (ve->reg),
2027 else if (ve->op == MULT)
2028 for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++)
2030 sum = simplify_gen_binary (MULT, GET_MODE (ve->reg),
2034 expr = force_operand (sum, ve->reg);
2035 if (expr != ve->reg)
2036 emit_move_insn (ve->reg, expr);
2040 insn = BB_HEAD (place);
2041 while (!NOTE_INSN_BASIC_BLOCK_P (insn))
2042 insn = NEXT_INSN (insn);
2044 emit_insn_after (seq, insn);
2046 /* Continue traversing the hash table. */
2050 /* Apply loop optimizations in loop copies using the
2051 data which gathered during the unrolling. Structure
2052 OPT_INFO record that data.
2054 UNROLLING is true if we unrolled (not peeled) the loop.
2055 REWRITE_ORIGINAL_BODY is true if we should also rewrite the original body of
2056 the loop (as it should happen in complete unrolling, but not in ordinary
2057 peeling of the loop). */
2060 apply_opt_in_copies (struct opt_info *opt_info,
2061 unsigned n_copies, bool unrolling,
2062 bool rewrite_original_loop)
2065 basic_block bb, orig_bb;
2066 rtx insn, orig_insn, next;
2067 struct iv_to_split ivts_templ, *ivts;
2068 struct var_to_expand ve_templ, *ves;
2070 /* Sanity check -- we need to put initialization in the original loop
2072 gcc_assert (!unrolling || rewrite_original_loop);
2074 /* Allocate the basic variables (i0). */
2075 if (opt_info->insns_to_split)
2076 htab_traverse (opt_info->insns_to_split, allocate_basic_variable, NULL);
2078 for (i = opt_info->first_new_block; i < (unsigned) last_basic_block; i++)
2080 bb = BASIC_BLOCK (i);
2081 orig_bb = get_bb_original (bb);
2083 /* bb->aux holds position in copy sequence initialized by
2084 duplicate_loop_to_header_edge. */
2085 delta = determine_split_iv_delta ((size_t)bb->aux, n_copies,
2088 orig_insn = BB_HEAD (orig_bb);
2089 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); insn = next)
2091 next = NEXT_INSN (insn);
2095 while (!INSN_P (orig_insn))
2096 orig_insn = NEXT_INSN (orig_insn);
2098 ivts_templ.insn = orig_insn;
2099 ve_templ.insn = orig_insn;
2101 /* Apply splitting iv optimization. */
2102 if (opt_info->insns_to_split)
2104 ivts = htab_find (opt_info->insns_to_split, &ivts_templ);
2108 #ifdef ENABLE_CHECKING
2109 gcc_assert (rtx_equal_p (PATTERN (insn), PATTERN (orig_insn)));
2113 insert_base_initialization (ivts, insn);
2114 split_iv (ivts, insn, delta);
2117 /* Apply variable expansion optimization. */
2118 if (unrolling && opt_info->insns_with_var_to_expand)
2120 ves = htab_find (opt_info->insns_with_var_to_expand, &ve_templ);
2123 #ifdef ENABLE_CHECKING
2124 gcc_assert (rtx_equal_p (PATTERN (insn), PATTERN (orig_insn)));
2126 expand_var_during_unrolling (ves, insn);
2129 orig_insn = NEXT_INSN (orig_insn);
2133 if (!rewrite_original_loop)
2136 /* Initialize the variable expansions in the loop preheader
2137 and take care of combining them at the loop exit. */
2138 if (opt_info->insns_with_var_to_expand)
2140 htab_traverse (opt_info->insns_with_var_to_expand,
2141 insert_var_expansion_initialization,
2142 opt_info->loop_preheader);
2143 htab_traverse (opt_info->insns_with_var_to_expand,
2144 combine_var_copies_in_loop_exit,
2145 opt_info->loop_exit);
2148 /* Rewrite also the original loop body. Find them as originals of the blocks
2149 in the last copied iteration, i.e. those that have
2150 get_bb_copy (get_bb_original (bb)) == bb. */
2151 for (i = opt_info->first_new_block; i < (unsigned) last_basic_block; i++)
2153 bb = BASIC_BLOCK (i);
2154 orig_bb = get_bb_original (bb);
2155 if (get_bb_copy (orig_bb) != bb)
2158 delta = determine_split_iv_delta (0, n_copies, unrolling);
2159 for (orig_insn = BB_HEAD (orig_bb);
2160 orig_insn != NEXT_INSN (BB_END (bb));
2163 next = NEXT_INSN (orig_insn);
2165 if (!INSN_P (orig_insn))
2168 ivts_templ.insn = orig_insn;
2169 if (opt_info->insns_to_split)
2171 ivts = htab_find (opt_info->insns_to_split, &ivts_templ);
2175 insert_base_initialization (ivts, orig_insn);
2176 split_iv (ivts, orig_insn, delta);
2185 /* Release the data structures used for the variable expansion
2186 optimization. Callbacks for htab_traverse. */
2189 release_var_copies (void **slot, void *data ATTRIBUTE_UNUSED)
2191 struct var_to_expand *ve = *slot;
2193 VEC_free (rtx, heap, ve->var_expansions);
2195 /* Continue traversing the hash table. */
2199 /* Release OPT_INFO. */
2202 free_opt_info (struct opt_info *opt_info)
2204 if (opt_info->insns_to_split)
2205 htab_delete (opt_info->insns_to_split);
2206 if (opt_info->insns_with_var_to_expand)
2208 htab_traverse (opt_info->insns_with_var_to_expand,
2209 release_var_copies, NULL);
2210 htab_delete (opt_info->insns_with_var_to_expand);