1 /* If-conversion support.
2 Copyright (C) 2000-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
30 #include "hard-reg-set.h"
34 #include "insn-config.h"
38 #include "dominance.h"
42 #include "cfgcleanup.h"
43 #include "basic-block.h"
45 #include "statistics.h"
58 #include "insn-codes.h"
60 #include "diagnostic-core.h"
64 #include "tree-pass.h"
67 #include "shrink-wrap.h"
80 #ifndef MAX_CONDITIONAL_EXECUTE
81 #define MAX_CONDITIONAL_EXECUTE \
82 (BRANCH_COST (optimize_function_for_speed_p (cfun), false) \
86 #ifndef HAVE_cbranchcc4
87 #define HAVE_cbranchcc4 0
90 #define IFCVT_MULTIPLE_DUMPS 1
92 #define NULL_BLOCK ((basic_block) NULL)
94 /* True if after combine pass. */
95 static bool ifcvt_after_combine;
97 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
98 static int num_possible_if_blocks;
100 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
102 static int num_updated_if_blocks;
104 /* # of changes made. */
105 static int num_true_changes;
107 /* Whether conditional execution changes were made. */
108 static int cond_exec_changed_p;
110 /* Forward references. */
111 static int count_bb_insns (const_basic_block);
112 static bool cheap_bb_rtx_cost_p (const_basic_block, int, int);
113 static rtx_insn *first_active_insn (basic_block);
114 static rtx_insn *last_active_insn (basic_block, int);
115 static rtx_insn *find_active_insn_before (basic_block, rtx_insn *);
116 static rtx_insn *find_active_insn_after (basic_block, rtx_insn *);
117 static basic_block block_fallthru (basic_block);
118 static int cond_exec_process_insns (ce_if_block *, rtx_insn *, rtx, rtx, int,
120 static rtx cond_exec_get_condition (rtx_insn *);
121 static rtx noce_get_condition (rtx_insn *, rtx_insn **, bool);
122 static int noce_operand_ok (const_rtx);
123 static void merge_if_block (ce_if_block *);
124 static int find_cond_trap (basic_block, edge, edge);
125 static basic_block find_if_header (basic_block, int);
126 static int block_jumps_and_fallthru_p (basic_block, basic_block);
127 static int noce_find_if_block (basic_block, edge, edge, int);
128 static int cond_exec_find_if_block (ce_if_block *);
129 static int find_if_case_1 (basic_block, edge, edge);
130 static int find_if_case_2 (basic_block, edge, edge);
131 static int dead_or_predicable (basic_block, basic_block, basic_block,
133 static void noce_emit_move_insn (rtx, rtx);
134 static rtx_insn *block_has_only_trap (basic_block);
136 /* Count the number of non-jump active insns in BB. */
139 count_bb_insns (const_basic_block bb)
142 rtx_insn *insn = BB_HEAD (bb);
146 if (active_insn_p (insn) && !JUMP_P (insn))
149 if (insn == BB_END (bb))
151 insn = NEXT_INSN (insn);
157 /* Determine whether the total insn_rtx_cost on non-jump insns in
158 basic block BB is less than MAX_COST. This function returns
159 false if the cost of any instruction could not be estimated.
161 The cost of the non-jump insns in BB is scaled by REG_BR_PROB_BASE
162 as those insns are being speculated. MAX_COST is scaled with SCALE
163 plus a small fudge factor. */
166 cheap_bb_rtx_cost_p (const_basic_block bb, int scale, int max_cost)
169 rtx_insn *insn = BB_HEAD (bb);
170 bool speed = optimize_bb_for_speed_p (bb);
172 /* Set scale to REG_BR_PROB_BASE to void the identical scaling
173 applied to insn_rtx_cost when optimizing for size. Only do
174 this after combine because if-conversion might interfere with
175 passes before combine.
177 Use optimize_function_for_speed_p instead of the pre-defined
178 variable speed to make sure it is set to same value for all
179 basic blocks in one if-conversion transformation. */
180 if (!optimize_function_for_speed_p (cfun) && ifcvt_after_combine)
181 scale = REG_BR_PROB_BASE;
182 /* Our branch probability/scaling factors are just estimates and don't
183 account for cases where we can get speculation for free and other
184 secondary benefits. So we fudge the scale factor to make speculating
185 appear a little more profitable when optimizing for performance. */
187 scale += REG_BR_PROB_BASE / 8;
194 if (NONJUMP_INSN_P (insn))
196 int cost = insn_rtx_cost (PATTERN (insn), speed) * REG_BR_PROB_BASE;
200 /* If this instruction is the load or set of a "stack" register,
201 such as a floating point register on x87, then the cost of
202 speculatively executing this insn may need to include
203 the additional cost of popping its result off of the
204 register stack. Unfortunately, correctly recognizing and
205 accounting for this additional overhead is tricky, so for
206 now we simply prohibit such speculative execution. */
209 rtx set = single_set (insn);
210 if (set && STACK_REG_P (SET_DEST (set)))
216 if (count >= max_cost)
219 else if (CALL_P (insn))
222 if (insn == BB_END (bb))
224 insn = NEXT_INSN (insn);
230 /* Return the first non-jump active insn in the basic block. */
233 first_active_insn (basic_block bb)
235 rtx_insn *insn = BB_HEAD (bb);
239 if (insn == BB_END (bb))
241 insn = NEXT_INSN (insn);
244 while (NOTE_P (insn) || DEBUG_INSN_P (insn))
246 if (insn == BB_END (bb))
248 insn = NEXT_INSN (insn);
257 /* Return the last non-jump active (non-jump) insn in the basic block. */
260 last_active_insn (basic_block bb, int skip_use_p)
262 rtx_insn *insn = BB_END (bb);
263 rtx_insn *head = BB_HEAD (bb);
267 || DEBUG_INSN_P (insn)
269 && NONJUMP_INSN_P (insn)
270 && GET_CODE (PATTERN (insn)) == USE))
274 insn = PREV_INSN (insn);
283 /* Return the active insn before INSN inside basic block CURR_BB. */
286 find_active_insn_before (basic_block curr_bb, rtx_insn *insn)
288 if (!insn || insn == BB_HEAD (curr_bb))
291 while ((insn = PREV_INSN (insn)) != NULL_RTX)
293 if (NONJUMP_INSN_P (insn) || JUMP_P (insn) || CALL_P (insn))
296 /* No other active insn all the way to the start of the basic block. */
297 if (insn == BB_HEAD (curr_bb))
304 /* Return the active insn after INSN inside basic block CURR_BB. */
307 find_active_insn_after (basic_block curr_bb, rtx_insn *insn)
309 if (!insn || insn == BB_END (curr_bb))
312 while ((insn = NEXT_INSN (insn)) != NULL_RTX)
314 if (NONJUMP_INSN_P (insn) || JUMP_P (insn) || CALL_P (insn))
317 /* No other active insn all the way to the end of the basic block. */
318 if (insn == BB_END (curr_bb))
325 /* Return the basic block reached by falling though the basic block BB. */
328 block_fallthru (basic_block bb)
330 edge e = find_fallthru_edge (bb->succs);
332 return (e) ? e->dest : NULL_BLOCK;
335 /* Return true if RTXs A and B can be safely interchanged. */
338 rtx_interchangeable_p (const_rtx a, const_rtx b)
340 if (!rtx_equal_p (a, b))
343 if (GET_CODE (a) != MEM)
346 /* A dead type-unsafe memory reference is legal, but a live type-unsafe memory
347 reference is not. Interchanging a dead type-unsafe memory reference with
348 a live type-safe one creates a live type-unsafe memory reference, in other
349 words, it makes the program illegal.
350 We check here conservatively whether the two memory references have equal
351 memory attributes. */
353 return mem_attrs_eq_p (get_mem_attrs (a), get_mem_attrs (b));
357 /* Go through a bunch of insns, converting them to conditional
358 execution format if possible. Return TRUE if all of the non-note
359 insns were processed. */
362 cond_exec_process_insns (ce_if_block *ce_info ATTRIBUTE_UNUSED,
363 /* if block information */rtx_insn *start,
364 /* first insn to look at */rtx end,
365 /* last insn to look at */rtx test,
366 /* conditional execution test */int prob_val,
367 /* probability of branch taken. */int mod_ok)
369 int must_be_last = FALSE;
377 for (insn = start; ; insn = NEXT_INSN (insn))
379 /* dwarf2out can't cope with conditional prologues. */
380 if (NOTE_P (insn) && NOTE_KIND (insn) == NOTE_INSN_PROLOGUE_END)
383 if (NOTE_P (insn) || DEBUG_INSN_P (insn))
386 gcc_assert (NONJUMP_INSN_P (insn) || CALL_P (insn));
388 /* dwarf2out can't cope with conditional unwind info. */
389 if (RTX_FRAME_RELATED_P (insn))
392 /* Remove USE insns that get in the way. */
393 if (reload_completed && GET_CODE (PATTERN (insn)) == USE)
395 /* ??? Ug. Actually unlinking the thing is problematic,
396 given what we'd have to coordinate with our callers. */
397 SET_INSN_DELETED (insn);
401 /* Last insn wasn't last? */
405 if (modified_in_p (test, insn))
412 /* Now build the conditional form of the instruction. */
413 pattern = PATTERN (insn);
414 xtest = copy_rtx (test);
416 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
418 if (GET_CODE (pattern) == COND_EXEC)
420 if (GET_MODE (xtest) != GET_MODE (COND_EXEC_TEST (pattern)))
423 xtest = gen_rtx_AND (GET_MODE (xtest), xtest,
424 COND_EXEC_TEST (pattern));
425 pattern = COND_EXEC_CODE (pattern);
428 pattern = gen_rtx_COND_EXEC (VOIDmode, xtest, pattern);
430 /* If the machine needs to modify the insn being conditionally executed,
431 say for example to force a constant integer operand into a temp
432 register, do so here. */
433 #ifdef IFCVT_MODIFY_INSN
434 IFCVT_MODIFY_INSN (ce_info, pattern, insn);
439 validate_change (insn, &PATTERN (insn), pattern, 1);
441 if (CALL_P (insn) && prob_val >= 0)
442 validate_change (insn, ®_NOTES (insn),
443 gen_rtx_INT_LIST ((machine_mode) REG_BR_PROB,
444 prob_val, REG_NOTES (insn)), 1);
454 /* Return the condition for a jump. Do not do any special processing. */
457 cond_exec_get_condition (rtx_insn *jump)
461 if (any_condjump_p (jump))
462 test_if = SET_SRC (pc_set (jump));
465 cond = XEXP (test_if, 0);
467 /* If this branches to JUMP_LABEL when the condition is false,
468 reverse the condition. */
469 if (GET_CODE (XEXP (test_if, 2)) == LABEL_REF
470 && LABEL_REF_LABEL (XEXP (test_if, 2)) == JUMP_LABEL (jump))
472 enum rtx_code rev = reversed_comparison_code (cond, jump);
476 cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
483 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
484 to conditional execution. Return TRUE if we were successful at
485 converting the block. */
488 cond_exec_process_if_block (ce_if_block * ce_info,
489 /* if block information */int do_multiple_p)
491 basic_block test_bb = ce_info->test_bb; /* last test block */
492 basic_block then_bb = ce_info->then_bb; /* THEN */
493 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
494 rtx test_expr; /* expression in IF_THEN_ELSE that is tested */
495 rtx_insn *then_start; /* first insn in THEN block */
496 rtx_insn *then_end; /* last insn + 1 in THEN block */
497 rtx_insn *else_start = NULL; /* first insn in ELSE block or NULL */
498 rtx_insn *else_end = NULL; /* last insn + 1 in ELSE block */
499 int max; /* max # of insns to convert. */
500 int then_mod_ok; /* whether conditional mods are ok in THEN */
501 rtx true_expr; /* test for else block insns */
502 rtx false_expr; /* test for then block insns */
503 int true_prob_val; /* probability of else block */
504 int false_prob_val; /* probability of then block */
505 rtx_insn *then_last_head = NULL; /* Last match at the head of THEN */
506 rtx_insn *else_last_head = NULL; /* Last match at the head of ELSE */
507 rtx_insn *then_first_tail = NULL; /* First match at the tail of THEN */
508 rtx_insn *else_first_tail = NULL; /* First match at the tail of ELSE */
509 int then_n_insns, else_n_insns, n_insns;
510 enum rtx_code false_code;
513 /* If test is comprised of && or || elements, and we've failed at handling
514 all of them together, just use the last test if it is the special case of
515 && elements without an ELSE block. */
516 if (!do_multiple_p && ce_info->num_multiple_test_blocks)
518 if (else_bb || ! ce_info->and_and_p)
521 ce_info->test_bb = test_bb = ce_info->last_test_bb;
522 ce_info->num_multiple_test_blocks = 0;
523 ce_info->num_and_and_blocks = 0;
524 ce_info->num_or_or_blocks = 0;
527 /* Find the conditional jump to the ELSE or JOIN part, and isolate
529 test_expr = cond_exec_get_condition (BB_END (test_bb));
533 /* If the conditional jump is more than just a conditional jump,
534 then we can not do conditional execution conversion on this block. */
535 if (! onlyjump_p (BB_END (test_bb)))
538 /* Collect the bounds of where we're to search, skipping any labels, jumps
539 and notes at the beginning and end of the block. Then count the total
540 number of insns and see if it is small enough to convert. */
541 then_start = first_active_insn (then_bb);
542 then_end = last_active_insn (then_bb, TRUE);
543 then_n_insns = ce_info->num_then_insns = count_bb_insns (then_bb);
544 n_insns = then_n_insns;
545 max = MAX_CONDITIONAL_EXECUTE;
552 else_start = first_active_insn (else_bb);
553 else_end = last_active_insn (else_bb, TRUE);
554 else_n_insns = ce_info->num_else_insns = count_bb_insns (else_bb);
555 n_insns += else_n_insns;
557 /* Look for matching sequences at the head and tail of the two blocks,
558 and limit the range of insns to be converted if possible. */
559 n_matching = flow_find_cross_jump (then_bb, else_bb,
560 &then_first_tail, &else_first_tail,
562 if (then_first_tail == BB_HEAD (then_bb))
563 then_start = then_end = NULL;
564 if (else_first_tail == BB_HEAD (else_bb))
565 else_start = else_end = NULL;
570 then_end = find_active_insn_before (then_bb, then_first_tail);
572 else_end = find_active_insn_before (else_bb, else_first_tail);
573 n_insns -= 2 * n_matching;
578 && then_n_insns > n_matching
579 && else_n_insns > n_matching)
581 int longest_match = MIN (then_n_insns - n_matching,
582 else_n_insns - n_matching);
584 = flow_find_head_matching_sequence (then_bb, else_bb,
593 /* We won't pass the insns in the head sequence to
594 cond_exec_process_insns, so we need to test them here
595 to make sure that they don't clobber the condition. */
596 for (insn = BB_HEAD (then_bb);
597 insn != NEXT_INSN (then_last_head);
598 insn = NEXT_INSN (insn))
599 if (!LABEL_P (insn) && !NOTE_P (insn)
600 && !DEBUG_INSN_P (insn)
601 && modified_in_p (test_expr, insn))
605 if (then_last_head == then_end)
606 then_start = then_end = NULL;
607 if (else_last_head == else_end)
608 else_start = else_end = NULL;
613 then_start = find_active_insn_after (then_bb, then_last_head);
615 else_start = find_active_insn_after (else_bb, else_last_head);
616 n_insns -= 2 * n_matching;
624 /* Map test_expr/test_jump into the appropriate MD tests to use on
625 the conditionally executed code. */
627 true_expr = test_expr;
629 false_code = reversed_comparison_code (true_expr, BB_END (test_bb));
630 if (false_code != UNKNOWN)
631 false_expr = gen_rtx_fmt_ee (false_code, GET_MODE (true_expr),
632 XEXP (true_expr, 0), XEXP (true_expr, 1));
634 false_expr = NULL_RTX;
636 #ifdef IFCVT_MODIFY_TESTS
637 /* If the machine description needs to modify the tests, such as setting a
638 conditional execution register from a comparison, it can do so here. */
639 IFCVT_MODIFY_TESTS (ce_info, true_expr, false_expr);
641 /* See if the conversion failed. */
642 if (!true_expr || !false_expr)
646 note = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX);
649 true_prob_val = XINT (note, 0);
650 false_prob_val = REG_BR_PROB_BASE - true_prob_val;
658 /* If we have && or || tests, do them here. These tests are in the adjacent
659 blocks after the first block containing the test. */
660 if (ce_info->num_multiple_test_blocks > 0)
662 basic_block bb = test_bb;
663 basic_block last_test_bb = ce_info->last_test_bb;
670 rtx_insn *start, *end;
672 enum rtx_code f_code;
674 bb = block_fallthru (bb);
675 start = first_active_insn (bb);
676 end = last_active_insn (bb, TRUE);
678 && ! cond_exec_process_insns (ce_info, start, end, false_expr,
679 false_prob_val, FALSE))
682 /* If the conditional jump is more than just a conditional jump, then
683 we can not do conditional execution conversion on this block. */
684 if (! onlyjump_p (BB_END (bb)))
687 /* Find the conditional jump and isolate the test. */
688 t = cond_exec_get_condition (BB_END (bb));
692 f_code = reversed_comparison_code (t, BB_END (bb));
693 if (f_code == UNKNOWN)
696 f = gen_rtx_fmt_ee (f_code, GET_MODE (t), XEXP (t, 0), XEXP (t, 1));
697 if (ce_info->and_and_p)
699 t = gen_rtx_AND (GET_MODE (t), true_expr, t);
700 f = gen_rtx_IOR (GET_MODE (t), false_expr, f);
704 t = gen_rtx_IOR (GET_MODE (t), true_expr, t);
705 f = gen_rtx_AND (GET_MODE (t), false_expr, f);
708 /* If the machine description needs to modify the tests, such as
709 setting a conditional execution register from a comparison, it can
711 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
712 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info, bb, t, f);
714 /* See if the conversion failed. */
722 while (bb != last_test_bb);
725 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
726 on then THEN block. */
727 then_mod_ok = (else_bb == NULL_BLOCK);
729 /* Go through the THEN and ELSE blocks converting the insns if possible
730 to conditional execution. */
734 || ! cond_exec_process_insns (ce_info, then_start, then_end,
735 false_expr, false_prob_val,
739 if (else_bb && else_end
740 && ! cond_exec_process_insns (ce_info, else_start, else_end,
741 true_expr, true_prob_val, TRUE))
744 /* If we cannot apply the changes, fail. Do not go through the normal fail
745 processing, since apply_change_group will call cancel_changes. */
746 if (! apply_change_group ())
748 #ifdef IFCVT_MODIFY_CANCEL
749 /* Cancel any machine dependent changes. */
750 IFCVT_MODIFY_CANCEL (ce_info);
755 #ifdef IFCVT_MODIFY_FINAL
756 /* Do any machine dependent final modifications. */
757 IFCVT_MODIFY_FINAL (ce_info);
760 /* Conversion succeeded. */
762 fprintf (dump_file, "%d insn%s converted to conditional execution.\n",
763 n_insns, (n_insns == 1) ? " was" : "s were");
765 /* Merge the blocks! If we had matching sequences, make sure to delete one
766 copy at the appropriate location first: delete the copy in the THEN branch
767 for a tail sequence so that the remaining one is executed last for both
768 branches, and delete the copy in the ELSE branch for a head sequence so
769 that the remaining one is executed first for both branches. */
772 rtx_insn *from = then_first_tail;
774 from = find_active_insn_after (then_bb, from);
775 delete_insn_chain (from, BB_END (then_bb), false);
778 delete_insn_chain (first_active_insn (else_bb), else_last_head, false);
780 merge_if_block (ce_info);
781 cond_exec_changed_p = TRUE;
785 #ifdef IFCVT_MODIFY_CANCEL
786 /* Cancel any machine dependent changes. */
787 IFCVT_MODIFY_CANCEL (ce_info);
794 /* Used by noce_process_if_block to communicate with its subroutines.
796 The subroutines know that A and B may be evaluated freely. They
797 know that X is a register. They should insert new instructions
798 before cond_earliest. */
802 /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block. */
803 basic_block test_bb, then_bb, else_bb, join_bb;
805 /* The jump that ends TEST_BB. */
808 /* The jump condition. */
811 /* New insns should be inserted before this one. */
812 rtx_insn *cond_earliest;
814 /* Insns in the THEN and ELSE block. There is always just this
815 one insns in those blocks. The insns are single_set insns.
816 If there was no ELSE block, INSN_B is the last insn before
817 COND_EARLIEST, or NULL_RTX. In the former case, the insn
818 operands are still valid, as if INSN_B was moved down below
820 rtx_insn *insn_a, *insn_b;
822 /* The SET_SRC of INSN_A and INSN_B. */
825 /* The SET_DEST of INSN_A. */
828 /* True if this if block is not canonical. In the canonical form of
829 if blocks, the THEN_BB is the block reached via the fallthru edge
830 from TEST_BB. For the noce transformations, we allow the symmetric
832 bool then_else_reversed;
834 /* Estimated cost of the particular branch instruction. */
838 static rtx noce_emit_store_flag (struct noce_if_info *, rtx, int, int);
839 static int noce_try_move (struct noce_if_info *);
840 static int noce_try_store_flag (struct noce_if_info *);
841 static int noce_try_addcc (struct noce_if_info *);
842 static int noce_try_store_flag_constants (struct noce_if_info *);
843 static int noce_try_store_flag_mask (struct noce_if_info *);
844 static rtx noce_emit_cmove (struct noce_if_info *, rtx, enum rtx_code, rtx,
846 static int noce_try_cmove (struct noce_if_info *);
847 static int noce_try_cmove_arith (struct noce_if_info *);
848 static rtx noce_get_alt_condition (struct noce_if_info *, rtx, rtx_insn **);
849 static int noce_try_minmax (struct noce_if_info *);
850 static int noce_try_abs (struct noce_if_info *);
851 static int noce_try_sign_mask (struct noce_if_info *);
853 /* Helper function for noce_try_store_flag*. */
856 noce_emit_store_flag (struct noce_if_info *if_info, rtx x, int reversep,
859 rtx cond = if_info->cond;
863 cond_complex = (! general_operand (XEXP (cond, 0), VOIDmode)
864 || ! general_operand (XEXP (cond, 1), VOIDmode));
866 /* If earliest == jump, or when the condition is complex, try to
867 build the store_flag insn directly. */
871 rtx set = pc_set (if_info->jump);
872 cond = XEXP (SET_SRC (set), 0);
873 if (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
874 && LABEL_REF_LABEL (XEXP (SET_SRC (set), 2)) == JUMP_LABEL (if_info->jump))
875 reversep = !reversep;
876 if (if_info->then_else_reversed)
877 reversep = !reversep;
881 code = reversed_comparison_code (cond, if_info->jump);
883 code = GET_CODE (cond);
885 if ((if_info->cond_earliest == if_info->jump || cond_complex)
886 && (normalize == 0 || STORE_FLAG_VALUE == normalize))
888 rtx src = gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (cond, 0),
890 rtx set = gen_rtx_SET (x, src);
893 rtx_insn *insn = emit_insn (set);
895 if (recog_memoized (insn) >= 0)
897 rtx_insn *seq = get_insns ();
901 if_info->cond_earliest = if_info->jump;
909 /* Don't even try if the comparison operands or the mode of X are weird. */
910 if (cond_complex || !SCALAR_INT_MODE_P (GET_MODE (x)))
913 return emit_store_flag (x, code, XEXP (cond, 0),
914 XEXP (cond, 1), VOIDmode,
915 (code == LTU || code == LEU
916 || code == GEU || code == GTU), normalize);
919 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
920 X is the destination/target and Y is the value to copy. */
923 noce_emit_move_insn (rtx x, rtx y)
925 machine_mode outmode;
929 if (GET_CODE (x) != STRICT_LOW_PART)
931 rtx_insn *seq, *insn;
936 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
937 otherwise construct a suitable SET pattern ourselves. */
938 insn = (OBJECT_P (y) || CONSTANT_P (y) || GET_CODE (y) == SUBREG)
939 ? emit_move_insn (x, y)
940 : emit_insn (gen_rtx_SET (x, y));
944 if (recog_memoized (insn) <= 0)
946 if (GET_CODE (x) == ZERO_EXTRACT)
948 rtx op = XEXP (x, 0);
949 unsigned HOST_WIDE_INT size = INTVAL (XEXP (x, 1));
950 unsigned HOST_WIDE_INT start = INTVAL (XEXP (x, 2));
952 /* store_bit_field expects START to be relative to
953 BYTES_BIG_ENDIAN and adjusts this value for machines with
954 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
955 invoke store_bit_field again it is necessary to have the START
956 value from the first call. */
957 if (BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN)
960 start = BITS_PER_UNIT - start - size;
963 gcc_assert (REG_P (op));
964 start = BITS_PER_WORD - start - size;
968 gcc_assert (start < (MEM_P (op) ? BITS_PER_UNIT : BITS_PER_WORD));
969 store_bit_field (op, size, start, 0, 0, GET_MODE (x), y);
973 switch (GET_RTX_CLASS (GET_CODE (y)))
976 ot = code_to_optab (GET_CODE (y));
980 target = expand_unop (GET_MODE (y), ot, XEXP (y, 0), x, 0);
981 if (target != NULL_RTX)
984 emit_move_insn (x, target);
993 ot = code_to_optab (GET_CODE (y));
997 target = expand_binop (GET_MODE (y), ot,
998 XEXP (y, 0), XEXP (y, 1),
1000 if (target != NULL_RTX)
1003 emit_move_insn (x, target);
1019 outer = XEXP (x, 0);
1020 inner = XEXP (outer, 0);
1021 outmode = GET_MODE (outer);
1022 bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT;
1023 store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos,
1027 /* Return the CC reg if it is used in COND. */
1030 cc_in_cond (rtx cond)
1032 if (HAVE_cbranchcc4 && cond
1033 && GET_MODE_CLASS (GET_MODE (XEXP (cond, 0))) == MODE_CC)
1034 return XEXP (cond, 0);
1039 /* Return sequence of instructions generated by if conversion. This
1040 function calls end_sequence() to end the current stream, ensures
1041 that the instructions are unshared, recognizable non-jump insns.
1042 On failure, this function returns a NULL_RTX. */
1045 end_ifcvt_sequence (struct noce_if_info *if_info)
1048 rtx_insn *seq = get_insns ();
1049 rtx cc = cc_in_cond (if_info->cond);
1051 set_used_flags (if_info->x);
1052 set_used_flags (if_info->cond);
1053 set_used_flags (if_info->a);
1054 set_used_flags (if_info->b);
1055 unshare_all_rtl_in_chain (seq);
1058 /* Make sure that all of the instructions emitted are recognizable,
1059 and that we haven't introduced a new jump instruction.
1060 As an exercise for the reader, build a general mechanism that
1061 allows proper placement of required clobbers. */
1062 for (insn = seq; insn; insn = NEXT_INSN (insn))
1064 || recog_memoized (insn) == -1
1065 /* Make sure new generated code does not clobber CC. */
1066 || (cc && set_of (cc, insn)))
1072 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
1073 "if (a == b) x = a; else x = b" into "x = b". */
1076 noce_try_move (struct noce_if_info *if_info)
1078 rtx cond = if_info->cond;
1079 enum rtx_code code = GET_CODE (cond);
1083 if (code != NE && code != EQ)
1086 /* This optimization isn't valid if either A or B could be a NaN
1087 or a signed zero. */
1088 if (HONOR_NANS (if_info->x)
1089 || HONOR_SIGNED_ZEROS (if_info->x))
1092 /* Check whether the operands of the comparison are A and in
1094 if ((rtx_equal_p (if_info->a, XEXP (cond, 0))
1095 && rtx_equal_p (if_info->b, XEXP (cond, 1)))
1096 || (rtx_equal_p (if_info->a, XEXP (cond, 1))
1097 && rtx_equal_p (if_info->b, XEXP (cond, 0))))
1099 if (!rtx_interchangeable_p (if_info->a, if_info->b))
1102 y = (code == EQ) ? if_info->a : if_info->b;
1104 /* Avoid generating the move if the source is the destination. */
1105 if (! rtx_equal_p (if_info->x, y))
1108 noce_emit_move_insn (if_info->x, y);
1109 seq = end_ifcvt_sequence (if_info);
1113 emit_insn_before_setloc (seq, if_info->jump,
1114 INSN_LOCATION (if_info->insn_a));
1121 /* Convert "if (test) x = 1; else x = 0".
1123 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
1124 tried in noce_try_store_flag_constants after noce_try_cmove has had
1125 a go at the conversion. */
1128 noce_try_store_flag (struct noce_if_info *if_info)
1134 if (CONST_INT_P (if_info->b)
1135 && INTVAL (if_info->b) == STORE_FLAG_VALUE
1136 && if_info->a == const0_rtx)
1138 else if (if_info->b == const0_rtx
1139 && CONST_INT_P (if_info->a)
1140 && INTVAL (if_info->a) == STORE_FLAG_VALUE
1141 && (reversed_comparison_code (if_info->cond, if_info->jump)
1149 target = noce_emit_store_flag (if_info, if_info->x, reversep, 0);
1152 if (target != if_info->x)
1153 noce_emit_move_insn (if_info->x, target);
1155 seq = end_ifcvt_sequence (if_info);
1159 emit_insn_before_setloc (seq, if_info->jump,
1160 INSN_LOCATION (if_info->insn_a));
1170 /* Convert "if (test) x = a; else x = b", for A and B constant. */
1173 noce_try_store_flag_constants (struct noce_if_info *if_info)
1178 HOST_WIDE_INT itrue, ifalse, diff, tmp;
1179 int normalize, can_reverse;
1182 if (CONST_INT_P (if_info->a)
1183 && CONST_INT_P (if_info->b))
1185 mode = GET_MODE (if_info->x);
1186 ifalse = INTVAL (if_info->a);
1187 itrue = INTVAL (if_info->b);
1189 diff = (unsigned HOST_WIDE_INT) itrue - ifalse;
1190 /* Make sure we can represent the difference between the two values. */
1192 != ((ifalse < 0) != (itrue < 0) ? ifalse < 0 : ifalse < itrue))
1195 diff = trunc_int_for_mode (diff, mode);
1197 can_reverse = (reversed_comparison_code (if_info->cond, if_info->jump)
1201 if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
1203 else if (ifalse == 0 && exact_log2 (itrue) >= 0
1204 && (STORE_FLAG_VALUE == 1
1205 || if_info->branch_cost >= 2))
1207 else if (itrue == 0 && exact_log2 (ifalse) >= 0 && can_reverse
1208 && (STORE_FLAG_VALUE == 1 || if_info->branch_cost >= 2))
1209 normalize = 1, reversep = 1;
1210 else if (itrue == -1
1211 && (STORE_FLAG_VALUE == -1
1212 || if_info->branch_cost >= 2))
1214 else if (ifalse == -1 && can_reverse
1215 && (STORE_FLAG_VALUE == -1 || if_info->branch_cost >= 2))
1216 normalize = -1, reversep = 1;
1217 else if ((if_info->branch_cost >= 2 && STORE_FLAG_VALUE == -1)
1218 || if_info->branch_cost >= 3)
1225 tmp = itrue; itrue = ifalse; ifalse = tmp;
1226 diff = trunc_int_for_mode (-(unsigned HOST_WIDE_INT) diff, mode);
1230 target = noce_emit_store_flag (if_info, if_info->x, reversep, normalize);
1237 /* if (test) x = 3; else x = 4;
1238 => x = 3 + (test == 0); */
1239 if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
1241 target = expand_simple_binop (mode,
1242 (diff == STORE_FLAG_VALUE
1244 gen_int_mode (ifalse, mode), target,
1245 if_info->x, 0, OPTAB_WIDEN);
1248 /* if (test) x = 8; else x = 0;
1249 => x = (test != 0) << 3; */
1250 else if (ifalse == 0 && (tmp = exact_log2 (itrue)) >= 0)
1252 target = expand_simple_binop (mode, ASHIFT,
1253 target, GEN_INT (tmp), if_info->x, 0,
1257 /* if (test) x = -1; else x = b;
1258 => x = -(test != 0) | b; */
1259 else if (itrue == -1)
1261 target = expand_simple_binop (mode, IOR,
1262 target, gen_int_mode (ifalse, mode),
1263 if_info->x, 0, OPTAB_WIDEN);
1266 /* if (test) x = a; else x = b;
1267 => x = (-(test != 0) & (b - a)) + a; */
1270 target = expand_simple_binop (mode, AND,
1271 target, gen_int_mode (diff, mode),
1272 if_info->x, 0, OPTAB_WIDEN);
1274 target = expand_simple_binop (mode, PLUS,
1275 target, gen_int_mode (ifalse, mode),
1276 if_info->x, 0, OPTAB_WIDEN);
1285 if (target != if_info->x)
1286 noce_emit_move_insn (if_info->x, target);
1288 seq = end_ifcvt_sequence (if_info);
1292 emit_insn_before_setloc (seq, if_info->jump,
1293 INSN_LOCATION (if_info->insn_a));
1300 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1301 similarly for "foo--". */
1304 noce_try_addcc (struct noce_if_info *if_info)
1308 int subtract, normalize;
1310 if (GET_CODE (if_info->a) == PLUS
1311 && rtx_equal_p (XEXP (if_info->a, 0), if_info->b)
1312 && (reversed_comparison_code (if_info->cond, if_info->jump)
1315 rtx cond = if_info->cond;
1316 enum rtx_code code = reversed_comparison_code (cond, if_info->jump);
1318 /* First try to use addcc pattern. */
1319 if (general_operand (XEXP (cond, 0), VOIDmode)
1320 && general_operand (XEXP (cond, 1), VOIDmode))
1323 target = emit_conditional_add (if_info->x, code,
1328 XEXP (if_info->a, 1),
1329 GET_MODE (if_info->x),
1330 (code == LTU || code == GEU
1331 || code == LEU || code == GTU));
1334 if (target != if_info->x)
1335 noce_emit_move_insn (if_info->x, target);
1337 seq = end_ifcvt_sequence (if_info);
1341 emit_insn_before_setloc (seq, if_info->jump,
1342 INSN_LOCATION (if_info->insn_a));
1348 /* If that fails, construct conditional increment or decrement using
1350 if (if_info->branch_cost >= 2
1351 && (XEXP (if_info->a, 1) == const1_rtx
1352 || XEXP (if_info->a, 1) == constm1_rtx))
1355 if (STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
1356 subtract = 0, normalize = 0;
1357 else if (-STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
1358 subtract = 1, normalize = 0;
1360 subtract = 0, normalize = INTVAL (XEXP (if_info->a, 1));
1363 target = noce_emit_store_flag (if_info,
1364 gen_reg_rtx (GET_MODE (if_info->x)),
1368 target = expand_simple_binop (GET_MODE (if_info->x),
1369 subtract ? MINUS : PLUS,
1370 if_info->b, target, if_info->x,
1374 if (target != if_info->x)
1375 noce_emit_move_insn (if_info->x, target);
1377 seq = end_ifcvt_sequence (if_info);
1381 emit_insn_before_setloc (seq, if_info->jump,
1382 INSN_LOCATION (if_info->insn_a));
1392 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1395 noce_try_store_flag_mask (struct noce_if_info *if_info)
1402 if ((if_info->branch_cost >= 2
1403 || STORE_FLAG_VALUE == -1)
1404 && ((if_info->a == const0_rtx
1405 && rtx_equal_p (if_info->b, if_info->x))
1406 || ((reversep = (reversed_comparison_code (if_info->cond,
1409 && if_info->b == const0_rtx
1410 && rtx_equal_p (if_info->a, if_info->x))))
1413 target = noce_emit_store_flag (if_info,
1414 gen_reg_rtx (GET_MODE (if_info->x)),
1417 target = expand_simple_binop (GET_MODE (if_info->x), AND,
1419 target, if_info->x, 0,
1424 int old_cost, new_cost, insn_cost;
1427 if (target != if_info->x)
1428 noce_emit_move_insn (if_info->x, target);
1430 seq = end_ifcvt_sequence (if_info);
1434 speed_p = optimize_bb_for_speed_p (BLOCK_FOR_INSN (if_info->insn_a));
1435 insn_cost = insn_rtx_cost (PATTERN (if_info->insn_a), speed_p);
1436 old_cost = COSTS_N_INSNS (if_info->branch_cost) + insn_cost;
1437 new_cost = seq_cost (seq, speed_p);
1439 if (new_cost > old_cost)
1442 emit_insn_before_setloc (seq, if_info->jump,
1443 INSN_LOCATION (if_info->insn_a));
1453 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1456 noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code,
1457 rtx cmp_a, rtx cmp_b, rtx vfalse, rtx vtrue)
1459 rtx target ATTRIBUTE_UNUSED;
1460 int unsignedp ATTRIBUTE_UNUSED;
1462 /* If earliest == jump, try to build the cmove insn directly.
1463 This is helpful when combine has created some complex condition
1464 (like for alpha's cmovlbs) that we can't hope to regenerate
1465 through the normal interface. */
1467 if (if_info->cond_earliest == if_info->jump)
1469 rtx cond = gen_rtx_fmt_ee (code, GET_MODE (if_info->cond), cmp_a, cmp_b);
1470 rtx if_then_else = gen_rtx_IF_THEN_ELSE (GET_MODE (x),
1471 cond, vtrue, vfalse);
1472 rtx set = gen_rtx_SET (x, if_then_else);
1475 rtx_insn *insn = emit_insn (set);
1477 if (recog_memoized (insn) >= 0)
1479 rtx_insn *seq = get_insns ();
1489 /* Don't even try if the comparison operands are weird
1490 except that the target supports cbranchcc4. */
1491 if (! general_operand (cmp_a, GET_MODE (cmp_a))
1492 || ! general_operand (cmp_b, GET_MODE (cmp_b)))
1494 if (!(HAVE_cbranchcc4)
1495 || GET_MODE_CLASS (GET_MODE (cmp_a)) != MODE_CC
1496 || cmp_b != const0_rtx)
1500 unsignedp = (code == LTU || code == GEU
1501 || code == LEU || code == GTU);
1503 target = emit_conditional_move (x, code, cmp_a, cmp_b, VOIDmode,
1504 vtrue, vfalse, GET_MODE (x),
1509 /* We might be faced with a situation like:
1512 vtrue = (subreg:M (reg:N VTRUE) BYTE)
1513 vfalse = (subreg:M (reg:N VFALSE) BYTE)
1515 We can't do a conditional move in mode M, but it's possible that we
1516 could do a conditional move in mode N instead and take a subreg of
1519 If we can't create new pseudos, though, don't bother. */
1520 if (reload_completed)
1523 if (GET_CODE (vtrue) == SUBREG && GET_CODE (vfalse) == SUBREG)
1525 rtx reg_vtrue = SUBREG_REG (vtrue);
1526 rtx reg_vfalse = SUBREG_REG (vfalse);
1527 unsigned int byte_vtrue = SUBREG_BYTE (vtrue);
1528 unsigned int byte_vfalse = SUBREG_BYTE (vfalse);
1529 rtx promoted_target;
1531 if (GET_MODE (reg_vtrue) != GET_MODE (reg_vfalse)
1532 || byte_vtrue != byte_vfalse
1533 || (SUBREG_PROMOTED_VAR_P (vtrue)
1534 != SUBREG_PROMOTED_VAR_P (vfalse))
1535 || (SUBREG_PROMOTED_GET (vtrue)
1536 != SUBREG_PROMOTED_GET (vfalse)))
1539 promoted_target = gen_reg_rtx (GET_MODE (reg_vtrue));
1541 target = emit_conditional_move (promoted_target, code, cmp_a, cmp_b,
1542 VOIDmode, reg_vtrue, reg_vfalse,
1543 GET_MODE (reg_vtrue), unsignedp);
1544 /* Nope, couldn't do it in that mode either. */
1548 target = gen_rtx_SUBREG (GET_MODE (vtrue), promoted_target, byte_vtrue);
1549 SUBREG_PROMOTED_VAR_P (target) = SUBREG_PROMOTED_VAR_P (vtrue);
1550 SUBREG_PROMOTED_SET (target, SUBREG_PROMOTED_GET (vtrue));
1551 emit_move_insn (x, target);
1558 /* Try only simple constants and registers here. More complex cases
1559 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1560 has had a go at it. */
1563 noce_try_cmove (struct noce_if_info *if_info)
1569 if ((CONSTANT_P (if_info->a) || register_operand (if_info->a, VOIDmode))
1570 && (CONSTANT_P (if_info->b) || register_operand (if_info->b, VOIDmode)))
1574 code = GET_CODE (if_info->cond);
1575 target = noce_emit_cmove (if_info, if_info->x, code,
1576 XEXP (if_info->cond, 0),
1577 XEXP (if_info->cond, 1),
1578 if_info->a, if_info->b);
1582 if (target != if_info->x)
1583 noce_emit_move_insn (if_info->x, target);
1585 seq = end_ifcvt_sequence (if_info);
1589 emit_insn_before_setloc (seq, if_info->jump,
1590 INSN_LOCATION (if_info->insn_a));
1603 /* Try more complex cases involving conditional_move. */
1606 noce_try_cmove_arith (struct noce_if_info *if_info)
1612 rtx_insn *insn_a, *insn_b;
1617 rtx_insn *ifcvt_seq;
1619 /* A conditional move from two memory sources is equivalent to a
1620 conditional on their addresses followed by a load. Don't do this
1621 early because it'll screw alias analysis. Note that we've
1622 already checked for no side effects. */
1623 /* ??? FIXME: Magic number 5. */
1624 if (cse_not_expected
1625 && MEM_P (a) && MEM_P (b)
1626 && MEM_ADDR_SPACE (a) == MEM_ADDR_SPACE (b)
1627 && if_info->branch_cost >= 5)
1629 machine_mode address_mode = get_address_mode (a);
1633 x = gen_reg_rtx (address_mode);
1637 /* ??? We could handle this if we knew that a load from A or B could
1638 not trap or fault. This is also true if we've already loaded
1639 from the address along the path from ENTRY. */
1640 else if (may_trap_or_fault_p (a) || may_trap_or_fault_p (b))
1643 /* if (test) x = a + b; else x = c - d;
1650 code = GET_CODE (if_info->cond);
1651 insn_a = if_info->insn_a;
1652 insn_b = if_info->insn_b;
1654 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1655 if insn_rtx_cost can't be estimated. */
1659 = insn_rtx_cost (PATTERN (insn_a),
1660 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a)));
1661 if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (if_info->branch_cost))
1670 += insn_rtx_cost (PATTERN (insn_b),
1671 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b)));
1672 if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (if_info->branch_cost))
1676 /* Possibly rearrange operands to make things come out more natural. */
1677 if (reversed_comparison_code (if_info->cond, if_info->jump) != UNKNOWN)
1680 if (rtx_equal_p (b, x))
1682 else if (general_operand (b, GET_MODE (b)))
1689 code = reversed_comparison_code (if_info->cond, if_info->jump);
1690 tmp = a, a = b, b = tmp;
1691 tmp_insn = insn_a, insn_a = insn_b, insn_b = tmp_insn;
1700 /* If either operand is complex, load it into a register first.
1701 The best way to do this is to copy the original insn. In this
1702 way we preserve any clobbers etc that the insn may have had.
1703 This is of course not possible in the IS_MEM case. */
1704 if (! general_operand (a, GET_MODE (a)))
1710 rtx reg = gen_reg_rtx (GET_MODE (a));
1711 insn = emit_insn (gen_rtx_SET (reg, a));
1714 goto end_seq_and_fail;
1717 a = gen_reg_rtx (GET_MODE (a));
1718 rtx_insn *copy_of_a = as_a <rtx_insn *> (copy_rtx (insn_a));
1719 rtx set = single_set (copy_of_a);
1721 insn = emit_insn (PATTERN (copy_of_a));
1723 if (recog_memoized (insn) < 0)
1724 goto end_seq_and_fail;
1726 if (! general_operand (b, GET_MODE (b)))
1734 rtx reg = gen_reg_rtx (GET_MODE (b));
1735 pat = gen_rtx_SET (reg, b);
1738 goto end_seq_and_fail;
1741 b = gen_reg_rtx (GET_MODE (b));
1742 rtx_insn *copy_of_insn_b = as_a <rtx_insn *> (copy_rtx (insn_b));
1743 rtx set = single_set (copy_of_insn_b);
1745 pat = PATTERN (copy_of_insn_b);
1748 /* If insn to set up A clobbers any registers B depends on, try to
1749 swap insn that sets up A with the one that sets up B. If even
1750 that doesn't help, punt. */
1751 last = get_last_insn ();
1752 if (last && modified_in_p (orig_b, last))
1754 new_insn = emit_insn_before (pat, get_insns ());
1755 if (modified_in_p (orig_a, new_insn))
1756 goto end_seq_and_fail;
1759 new_insn = emit_insn (pat);
1761 if (recog_memoized (new_insn) < 0)
1762 goto end_seq_and_fail;
1765 target = noce_emit_cmove (if_info, x, code, XEXP (if_info->cond, 0),
1766 XEXP (if_info->cond, 1), a, b);
1769 goto end_seq_and_fail;
1771 /* If we're handling a memory for above, emit the load now. */
1774 rtx mem = gen_rtx_MEM (GET_MODE (if_info->x), target);
1776 /* Copy over flags as appropriate. */
1777 if (MEM_VOLATILE_P (if_info->a) || MEM_VOLATILE_P (if_info->b))
1778 MEM_VOLATILE_P (mem) = 1;
1779 if (MEM_ALIAS_SET (if_info->a) == MEM_ALIAS_SET (if_info->b))
1780 set_mem_alias_set (mem, MEM_ALIAS_SET (if_info->a));
1782 MIN (MEM_ALIGN (if_info->a), MEM_ALIGN (if_info->b)));
1784 gcc_assert (MEM_ADDR_SPACE (if_info->a) == MEM_ADDR_SPACE (if_info->b));
1785 set_mem_addr_space (mem, MEM_ADDR_SPACE (if_info->a));
1787 noce_emit_move_insn (if_info->x, mem);
1789 else if (target != x)
1790 noce_emit_move_insn (x, target);
1792 ifcvt_seq = end_ifcvt_sequence (if_info);
1796 emit_insn_before_setloc (ifcvt_seq, if_info->jump,
1797 INSN_LOCATION (if_info->insn_a));
1805 /* For most cases, the simplified condition we found is the best
1806 choice, but this is not the case for the min/max/abs transforms.
1807 For these we wish to know that it is A or B in the condition. */
1810 noce_get_alt_condition (struct noce_if_info *if_info, rtx target,
1811 rtx_insn **earliest)
1817 /* If target is already mentioned in the known condition, return it. */
1818 if (reg_mentioned_p (target, if_info->cond))
1820 *earliest = if_info->cond_earliest;
1821 return if_info->cond;
1824 set = pc_set (if_info->jump);
1825 cond = XEXP (SET_SRC (set), 0);
1827 = GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
1828 && LABEL_REF_LABEL (XEXP (SET_SRC (set), 2)) == JUMP_LABEL (if_info->jump);
1829 if (if_info->then_else_reversed)
1832 /* If we're looking for a constant, try to make the conditional
1833 have that constant in it. There are two reasons why it may
1834 not have the constant we want:
1836 1. GCC may have needed to put the constant in a register, because
1837 the target can't compare directly against that constant. For
1838 this case, we look for a SET immediately before the comparison
1839 that puts a constant in that register.
1841 2. GCC may have canonicalized the conditional, for example
1842 replacing "if x < 4" with "if x <= 3". We can undo that (or
1843 make equivalent types of changes) to get the constants we need
1844 if they're off by one in the right direction. */
1846 if (CONST_INT_P (target))
1848 enum rtx_code code = GET_CODE (if_info->cond);
1849 rtx op_a = XEXP (if_info->cond, 0);
1850 rtx op_b = XEXP (if_info->cond, 1);
1851 rtx_insn *prev_insn;
1853 /* First, look to see if we put a constant in a register. */
1854 prev_insn = prev_nonnote_insn (if_info->cond_earliest);
1856 && BLOCK_FOR_INSN (prev_insn)
1857 == BLOCK_FOR_INSN (if_info->cond_earliest)
1858 && INSN_P (prev_insn)
1859 && GET_CODE (PATTERN (prev_insn)) == SET)
1861 rtx src = find_reg_equal_equiv_note (prev_insn);
1863 src = SET_SRC (PATTERN (prev_insn));
1864 if (CONST_INT_P (src))
1866 if (rtx_equal_p (op_a, SET_DEST (PATTERN (prev_insn))))
1868 else if (rtx_equal_p (op_b, SET_DEST (PATTERN (prev_insn))))
1871 if (CONST_INT_P (op_a))
1876 code = swap_condition (code);
1881 /* Now, look to see if we can get the right constant by
1882 adjusting the conditional. */
1883 if (CONST_INT_P (op_b))
1885 HOST_WIDE_INT desired_val = INTVAL (target);
1886 HOST_WIDE_INT actual_val = INTVAL (op_b);
1891 if (actual_val == desired_val + 1)
1894 op_b = GEN_INT (desired_val);
1898 if (actual_val == desired_val - 1)
1901 op_b = GEN_INT (desired_val);
1905 if (actual_val == desired_val - 1)
1908 op_b = GEN_INT (desired_val);
1912 if (actual_val == desired_val + 1)
1915 op_b = GEN_INT (desired_val);
1923 /* If we made any changes, generate a new conditional that is
1924 equivalent to what we started with, but has the right
1926 if (code != GET_CODE (if_info->cond)
1927 || op_a != XEXP (if_info->cond, 0)
1928 || op_b != XEXP (if_info->cond, 1))
1930 cond = gen_rtx_fmt_ee (code, GET_MODE (cond), op_a, op_b);
1931 *earliest = if_info->cond_earliest;
1936 cond = canonicalize_condition (if_info->jump, cond, reverse,
1937 earliest, target, HAVE_cbranchcc4, true);
1938 if (! cond || ! reg_mentioned_p (target, cond))
1941 /* We almost certainly searched back to a different place.
1942 Need to re-verify correct lifetimes. */
1944 /* X may not be mentioned in the range (cond_earliest, jump]. */
1945 for (insn = if_info->jump; insn != *earliest; insn = PREV_INSN (insn))
1946 if (INSN_P (insn) && reg_overlap_mentioned_p (if_info->x, PATTERN (insn)))
1949 /* A and B may not be modified in the range [cond_earliest, jump). */
1950 for (insn = *earliest; insn != if_info->jump; insn = NEXT_INSN (insn))
1952 && (modified_in_p (if_info->a, insn)
1953 || modified_in_p (if_info->b, insn)))
1959 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1962 noce_try_minmax (struct noce_if_info *if_info)
1965 rtx_insn *earliest, *seq;
1966 enum rtx_code code, op;
1969 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1970 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1971 to get the target to tell us... */
1972 if (HONOR_SIGNED_ZEROS (if_info->x)
1973 || HONOR_NANS (if_info->x))
1976 cond = noce_get_alt_condition (if_info, if_info->a, &earliest);
1980 /* Verify the condition is of the form we expect, and canonicalize
1981 the comparison code. */
1982 code = GET_CODE (cond);
1983 if (rtx_equal_p (XEXP (cond, 0), if_info->a))
1985 if (! rtx_equal_p (XEXP (cond, 1), if_info->b))
1988 else if (rtx_equal_p (XEXP (cond, 1), if_info->a))
1990 if (! rtx_equal_p (XEXP (cond, 0), if_info->b))
1992 code = swap_condition (code);
1997 /* Determine what sort of operation this is. Note that the code is for
1998 a taken branch, so the code->operation mapping appears backwards. */
2031 target = expand_simple_binop (GET_MODE (if_info->x), op,
2032 if_info->a, if_info->b,
2033 if_info->x, unsignedp, OPTAB_WIDEN);
2039 if (target != if_info->x)
2040 noce_emit_move_insn (if_info->x, target);
2042 seq = end_ifcvt_sequence (if_info);
2046 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATION (if_info->insn_a));
2047 if_info->cond = cond;
2048 if_info->cond_earliest = earliest;
2053 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
2054 "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
2058 noce_try_abs (struct noce_if_info *if_info)
2060 rtx cond, target, a, b, c;
2061 rtx_insn *earliest, *seq;
2063 bool one_cmpl = false;
2065 /* Reject modes with signed zeros. */
2066 if (HONOR_SIGNED_ZEROS (if_info->x))
2069 /* Recognize A and B as constituting an ABS or NABS. The canonical
2070 form is a branch around the negation, taken when the object is the
2071 first operand of a comparison against 0 that evaluates to true. */
2074 if (GET_CODE (a) == NEG && rtx_equal_p (XEXP (a, 0), b))
2076 else if (GET_CODE (b) == NEG && rtx_equal_p (XEXP (b, 0), a))
2078 c = a; a = b; b = c;
2081 else if (GET_CODE (a) == NOT && rtx_equal_p (XEXP (a, 0), b))
2086 else if (GET_CODE (b) == NOT && rtx_equal_p (XEXP (b, 0), a))
2088 c = a; a = b; b = c;
2095 cond = noce_get_alt_condition (if_info, b, &earliest);
2099 /* Verify the condition is of the form we expect. */
2100 if (rtx_equal_p (XEXP (cond, 0), b))
2102 else if (rtx_equal_p (XEXP (cond, 1), b))
2110 /* Verify that C is zero. Search one step backward for a
2111 REG_EQUAL note or a simple source if necessary. */
2115 rtx_insn *insn = prev_nonnote_insn (earliest);
2117 && BLOCK_FOR_INSN (insn) == BLOCK_FOR_INSN (earliest)
2118 && (set = single_set (insn))
2119 && rtx_equal_p (SET_DEST (set), c))
2121 rtx note = find_reg_equal_equiv_note (insn);
2131 && GET_CODE (XEXP (c, 0)) == SYMBOL_REF
2132 && CONSTANT_POOL_ADDRESS_P (XEXP (c, 0)))
2133 c = get_pool_constant (XEXP (c, 0));
2135 /* Work around funny ideas get_condition has wrt canonicalization.
2136 Note that these rtx constants are known to be CONST_INT, and
2137 therefore imply integer comparisons. */
2138 if (c == constm1_rtx && GET_CODE (cond) == GT)
2140 else if (c == const1_rtx && GET_CODE (cond) == LT)
2142 else if (c != CONST0_RTX (GET_MODE (b)))
2145 /* Determine what sort of operation this is. */
2146 switch (GET_CODE (cond))
2165 target = expand_one_cmpl_abs_nojump (GET_MODE (if_info->x), b,
2168 target = expand_abs_nojump (GET_MODE (if_info->x), b, if_info->x, 1);
2170 /* ??? It's a quandary whether cmove would be better here, especially
2171 for integers. Perhaps combine will clean things up. */
2172 if (target && negate)
2175 target = expand_simple_unop (GET_MODE (target), NOT, target,
2178 target = expand_simple_unop (GET_MODE (target), NEG, target,
2188 if (target != if_info->x)
2189 noce_emit_move_insn (if_info->x, target);
2191 seq = end_ifcvt_sequence (if_info);
2195 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATION (if_info->insn_a));
2196 if_info->cond = cond;
2197 if_info->cond_earliest = earliest;
2202 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
2205 noce_try_sign_mask (struct noce_if_info *if_info)
2211 bool t_unconditional;
2213 cond = if_info->cond;
2214 code = GET_CODE (cond);
2219 if (if_info->a == const0_rtx)
2221 if ((code == LT && c == const0_rtx)
2222 || (code == LE && c == constm1_rtx))
2225 else if (if_info->b == const0_rtx)
2227 if ((code == GE && c == const0_rtx)
2228 || (code == GT && c == constm1_rtx))
2232 if (! t || side_effects_p (t))
2235 /* We currently don't handle different modes. */
2236 mode = GET_MODE (t);
2237 if (GET_MODE (m) != mode)
2240 /* This is only profitable if T is unconditionally executed/evaluated in the
2241 original insn sequence or T is cheap. The former happens if B is the
2242 non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
2243 INSN_B which can happen for e.g. conditional stores to memory. For the
2244 cost computation use the block TEST_BB where the evaluation will end up
2245 after the transformation. */
2248 && (if_info->insn_b == NULL_RTX
2249 || BLOCK_FOR_INSN (if_info->insn_b) == if_info->test_bb));
2250 if (!(t_unconditional
2251 || (set_src_cost (t, optimize_bb_for_speed_p (if_info->test_bb))
2252 < COSTS_N_INSNS (2))))
2256 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
2257 "(signed) m >> 31" directly. This benefits targets with specialized
2258 insns to obtain the signmask, but still uses ashr_optab otherwise. */
2259 m = emit_store_flag (gen_reg_rtx (mode), LT, m, const0_rtx, mode, 0, -1);
2260 t = m ? expand_binop (mode, and_optab, m, t, NULL_RTX, 0, OPTAB_DIRECT)
2269 noce_emit_move_insn (if_info->x, t);
2271 seq = end_ifcvt_sequence (if_info);
2275 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATION (if_info->insn_a));
2280 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
2284 noce_try_bitop (struct noce_if_info *if_info)
2286 rtx cond, x, a, result;
2293 cond = if_info->cond;
2294 code = GET_CODE (cond);
2296 /* Check for no else condition. */
2297 if (! rtx_equal_p (x, if_info->b))
2300 /* Check for a suitable condition. */
2301 if (code != NE && code != EQ)
2303 if (XEXP (cond, 1) != const0_rtx)
2305 cond = XEXP (cond, 0);
2307 /* ??? We could also handle AND here. */
2308 if (GET_CODE (cond) == ZERO_EXTRACT)
2310 if (XEXP (cond, 1) != const1_rtx
2311 || !CONST_INT_P (XEXP (cond, 2))
2312 || ! rtx_equal_p (x, XEXP (cond, 0)))
2314 bitnum = INTVAL (XEXP (cond, 2));
2315 mode = GET_MODE (x);
2316 if (BITS_BIG_ENDIAN)
2317 bitnum = GET_MODE_BITSIZE (mode) - 1 - bitnum;
2318 if (bitnum < 0 || bitnum >= HOST_BITS_PER_WIDE_INT)
2325 if (GET_CODE (a) == IOR || GET_CODE (a) == XOR)
2327 /* Check for "if (X & C) x = x op C". */
2328 if (! rtx_equal_p (x, XEXP (a, 0))
2329 || !CONST_INT_P (XEXP (a, 1))
2330 || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
2331 != (unsigned HOST_WIDE_INT) 1 << bitnum)
2334 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
2335 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
2336 if (GET_CODE (a) == IOR)
2337 result = (code == NE) ? a : NULL_RTX;
2338 else if (code == NE)
2340 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
2341 result = gen_int_mode ((HOST_WIDE_INT) 1 << bitnum, mode);
2342 result = simplify_gen_binary (IOR, mode, x, result);
2346 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2347 result = gen_int_mode (~((HOST_WIDE_INT) 1 << bitnum), mode);
2348 result = simplify_gen_binary (AND, mode, x, result);
2351 else if (GET_CODE (a) == AND)
2353 /* Check for "if (X & C) x &= ~C". */
2354 if (! rtx_equal_p (x, XEXP (a, 0))
2355 || !CONST_INT_P (XEXP (a, 1))
2356 || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
2357 != (~((HOST_WIDE_INT) 1 << bitnum) & GET_MODE_MASK (mode)))
2360 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2361 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2362 result = (code == EQ) ? a : NULL_RTX;
2370 noce_emit_move_insn (x, result);
2371 seq = end_ifcvt_sequence (if_info);
2375 emit_insn_before_setloc (seq, if_info->jump,
2376 INSN_LOCATION (if_info->insn_a));
2382 /* Similar to get_condition, only the resulting condition must be
2383 valid at JUMP, instead of at EARLIEST.
2385 If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
2386 THEN block of the caller, and we have to reverse the condition. */
2389 noce_get_condition (rtx_insn *jump, rtx_insn **earliest, bool then_else_reversed)
2394 if (! any_condjump_p (jump))
2397 set = pc_set (jump);
2399 /* If this branches to JUMP_LABEL when the condition is false,
2400 reverse the condition. */
2401 reverse = (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
2402 && LABEL_REF_LABEL (XEXP (SET_SRC (set), 2)) == JUMP_LABEL (jump));
2404 /* We may have to reverse because the caller's if block is not canonical,
2405 i.e. the THEN block isn't the fallthrough block for the TEST block
2406 (see find_if_header). */
2407 if (then_else_reversed)
2410 /* If the condition variable is a register and is MODE_INT, accept it. */
2412 cond = XEXP (SET_SRC (set), 0);
2413 tmp = XEXP (cond, 0);
2414 if (REG_P (tmp) && GET_MODE_CLASS (GET_MODE (tmp)) == MODE_INT
2415 && (GET_MODE (tmp) != BImode
2416 || !targetm.small_register_classes_for_mode_p (BImode)))
2421 cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
2422 GET_MODE (cond), tmp, XEXP (cond, 1));
2426 /* Otherwise, fall back on canonicalize_condition to do the dirty
2427 work of manipulating MODE_CC values and COMPARE rtx codes. */
2428 tmp = canonicalize_condition (jump, cond, reverse, earliest,
2429 NULL_RTX, HAVE_cbranchcc4, true);
2431 /* We don't handle side-effects in the condition, like handling
2432 REG_INC notes and making sure no duplicate conditions are emitted. */
2433 if (tmp != NULL_RTX && side_effects_p (tmp))
2439 /* Return true if OP is ok for if-then-else processing. */
2442 noce_operand_ok (const_rtx op)
2444 if (side_effects_p (op))
2447 /* We special-case memories, so handle any of them with
2448 no address side effects. */
2450 return ! side_effects_p (XEXP (op, 0));
2452 return ! may_trap_p (op);
2455 /* Return true if a write into MEM may trap or fault. */
2458 noce_mem_write_may_trap_or_fault_p (const_rtx mem)
2462 if (MEM_READONLY_P (mem))
2465 if (may_trap_or_fault_p (mem))
2468 addr = XEXP (mem, 0);
2470 /* Call target hook to avoid the effects of -fpic etc.... */
2471 addr = targetm.delegitimize_address (addr);
2474 switch (GET_CODE (addr))
2482 addr = XEXP (addr, 0);
2486 addr = XEXP (addr, 1);
2489 if (CONST_INT_P (XEXP (addr, 1)))
2490 addr = XEXP (addr, 0);
2497 if (SYMBOL_REF_DECL (addr)
2498 && decl_readonly_section (SYMBOL_REF_DECL (addr), 0))
2508 /* Return whether we can use store speculation for MEM. TOP_BB is the
2509 basic block above the conditional block where we are considering
2510 doing the speculative store. We look for whether MEM is set
2511 unconditionally later in the function. */
2514 noce_can_store_speculate_p (basic_block top_bb, const_rtx mem)
2516 basic_block dominator;
2518 for (dominator = get_immediate_dominator (CDI_POST_DOMINATORS, top_bb);
2520 dominator = get_immediate_dominator (CDI_POST_DOMINATORS, dominator))
2524 FOR_BB_INSNS (dominator, insn)
2526 /* If we see something that might be a memory barrier, we
2527 have to stop looking. Even if the MEM is set later in
2528 the function, we still don't want to set it
2529 unconditionally before the barrier. */
2531 && (volatile_insn_p (PATTERN (insn))
2532 || (CALL_P (insn) && (!RTL_CONST_CALL_P (insn)))))
2535 if (memory_must_be_modified_in_insn_p (mem, insn))
2537 if (modified_in_p (XEXP (mem, 0), insn))
2546 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2547 it without using conditional execution. Return TRUE if we were successful
2548 at converting the block. */
2551 noce_process_if_block (struct noce_if_info *if_info)
2553 basic_block test_bb = if_info->test_bb; /* test block */
2554 basic_block then_bb = if_info->then_bb; /* THEN */
2555 basic_block else_bb = if_info->else_bb; /* ELSE or NULL */
2556 basic_block join_bb = if_info->join_bb; /* JOIN */
2557 rtx_insn *jump = if_info->jump;
2558 rtx cond = if_info->cond;
2559 rtx_insn *insn_a, *insn_b;
2561 rtx orig_x, x, a, b;
2564 /* We're looking for patterns of the form
2566 (1) if (...) x = a; else x = b;
2567 (2) x = b; if (...) x = a;
2568 (3) if (...) x = a; // as if with an initial x = x.
2570 The later patterns require jumps to be more expensive.
2572 ??? For future expansion, look for multiple X in such patterns. */
2574 /* Look for one of the potential sets. */
2575 insn_a = first_active_insn (then_bb);
2577 || insn_a != last_active_insn (then_bb, FALSE)
2578 || (set_a = single_set (insn_a)) == NULL_RTX)
2581 x = SET_DEST (set_a);
2582 a = SET_SRC (set_a);
2584 /* Look for the other potential set. Make sure we've got equivalent
2586 /* ??? This is overconservative. Storing to two different mems is
2587 as easy as conditionally computing the address. Storing to a
2588 single mem merely requires a scratch memory to use as one of the
2589 destination addresses; often the memory immediately below the
2590 stack pointer is available for this. */
2594 insn_b = first_active_insn (else_bb);
2596 || insn_b != last_active_insn (else_bb, FALSE)
2597 || (set_b = single_set (insn_b)) == NULL_RTX
2598 || ! rtx_interchangeable_p (x, SET_DEST (set_b)))
2603 insn_b = prev_nonnote_nondebug_insn (if_info->cond_earliest);
2604 /* We're going to be moving the evaluation of B down from above
2605 COND_EARLIEST to JUMP. Make sure the relevant data is still
2608 || BLOCK_FOR_INSN (insn_b) != BLOCK_FOR_INSN (if_info->cond_earliest)
2609 || !NONJUMP_INSN_P (insn_b)
2610 || (set_b = single_set (insn_b)) == NULL_RTX
2611 || ! rtx_interchangeable_p (x, SET_DEST (set_b))
2612 || ! noce_operand_ok (SET_SRC (set_b))
2613 || reg_overlap_mentioned_p (x, SET_SRC (set_b))
2614 || modified_between_p (SET_SRC (set_b), insn_b, jump)
2615 /* Avoid extending the lifetime of hard registers on small
2616 register class machines. */
2617 || (REG_P (SET_SRC (set_b))
2618 && HARD_REGISTER_P (SET_SRC (set_b))
2619 && targetm.small_register_classes_for_mode_p
2620 (GET_MODE (SET_SRC (set_b))))
2621 /* Likewise with X. In particular this can happen when
2622 noce_get_condition looks farther back in the instruction
2623 stream than one might expect. */
2624 || reg_overlap_mentioned_p (x, cond)
2625 || reg_overlap_mentioned_p (x, a)
2626 || modified_between_p (x, insn_b, jump))
2633 /* If x has side effects then only the if-then-else form is safe to
2634 convert. But even in that case we would need to restore any notes
2635 (such as REG_INC) at then end. That can be tricky if
2636 noce_emit_move_insn expands to more than one insn, so disable the
2637 optimization entirely for now if there are side effects. */
2638 if (side_effects_p (x))
2641 b = (set_b ? SET_SRC (set_b) : x);
2643 /* Only operate on register destinations, and even then avoid extending
2644 the lifetime of hard registers on small register class machines. */
2647 || (HARD_REGISTER_P (x)
2648 && targetm.small_register_classes_for_mode_p (GET_MODE (x))))
2650 if (GET_MODE (x) == BLKmode)
2653 if (GET_CODE (x) == ZERO_EXTRACT
2654 && (!CONST_INT_P (XEXP (x, 1))
2655 || !CONST_INT_P (XEXP (x, 2))))
2658 x = gen_reg_rtx (GET_MODE (GET_CODE (x) == STRICT_LOW_PART
2659 ? XEXP (x, 0) : x));
2662 /* Don't operate on sources that may trap or are volatile. */
2663 if (! noce_operand_ok (a) || ! noce_operand_ok (b))
2667 /* Set up the info block for our subroutines. */
2668 if_info->insn_a = insn_a;
2669 if_info->insn_b = insn_b;
2674 /* Skip it if the instruction to be moved might clobber CC. */
2675 cc = cc_in_cond (cond);
2677 && (set_of (cc, insn_a)
2678 || (insn_b && set_of (cc, insn_b))))
2681 /* Try optimizations in some approximation of a useful order. */
2682 /* ??? Should first look to see if X is live incoming at all. If it
2683 isn't, we don't need anything but an unconditional set. */
2685 /* Look and see if A and B are really the same. Avoid creating silly
2686 cmove constructs that no one will fix up later. */
2687 if (rtx_interchangeable_p (a, b))
2689 /* If we have an INSN_B, we don't have to create any new rtl. Just
2690 move the instruction that we already have. If we don't have an
2691 INSN_B, that means that A == X, and we've got a noop move. In
2692 that case don't do anything and let the code below delete INSN_A. */
2693 if (insn_b && else_bb)
2697 if (else_bb && insn_b == BB_END (else_bb))
2698 BB_END (else_bb) = PREV_INSN (insn_b);
2699 reorder_insns (insn_b, insn_b, PREV_INSN (jump));
2701 /* If there was a REG_EQUAL note, delete it since it may have been
2702 true due to this insn being after a jump. */
2703 if ((note = find_reg_note (insn_b, REG_EQUAL, NULL_RTX)) != 0)
2704 remove_note (insn_b, note);
2708 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2709 x must be executed twice. */
2710 else if (insn_b && side_effects_p (orig_x))
2717 if (!set_b && MEM_P (orig_x))
2719 /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
2720 for optimizations if writing to x may trap or fault,
2721 i.e. it's a memory other than a static var or a stack slot,
2722 is misaligned on strict aligned machines or is read-only. If
2723 x is a read-only memory, then the program is valid only if we
2724 avoid the store into it. If there are stores on both the
2725 THEN and ELSE arms, then we can go ahead with the conversion;
2726 either the program is broken, or the condition is always
2727 false such that the other memory is selected. */
2728 if (noce_mem_write_may_trap_or_fault_p (orig_x))
2731 /* Avoid store speculation: given "if (...) x = a" where x is a
2732 MEM, we only want to do the store if x is always set
2733 somewhere in the function. This avoids cases like
2734 if (pthread_mutex_trylock(mutex))
2736 where we only want global_variable to be changed if the mutex
2737 is held. FIXME: This should ideally be expressed directly in
2739 if (!noce_can_store_speculate_p (test_bb, orig_x))
2743 if (noce_try_move (if_info))
2745 if (noce_try_store_flag (if_info))
2747 if (noce_try_bitop (if_info))
2749 if (noce_try_minmax (if_info))
2751 if (noce_try_abs (if_info))
2753 if (HAVE_conditional_move
2754 && noce_try_cmove (if_info))
2756 if (! targetm.have_conditional_execution ())
2758 if (noce_try_store_flag_constants (if_info))
2760 if (noce_try_addcc (if_info))
2762 if (noce_try_store_flag_mask (if_info))
2764 if (HAVE_conditional_move
2765 && noce_try_cmove_arith (if_info))
2767 if (noce_try_sign_mask (if_info))
2771 if (!else_bb && set_b)
2783 /* If we used a temporary, fix it up now. */
2789 noce_emit_move_insn (orig_x, x);
2791 set_used_flags (orig_x);
2792 unshare_all_rtl_in_chain (seq);
2795 emit_insn_before_setloc (seq, BB_END (test_bb), INSN_LOCATION (insn_a));
2798 /* The original THEN and ELSE blocks may now be removed. The test block
2799 must now jump to the join block. If the test block and the join block
2800 can be merged, do so. */
2803 delete_basic_block (else_bb);
2807 remove_edge (find_edge (test_bb, join_bb));
2809 remove_edge (find_edge (then_bb, join_bb));
2810 redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb);
2811 delete_basic_block (then_bb);
2814 if (can_merge_blocks_p (test_bb, join_bb))
2816 merge_blocks (test_bb, join_bb);
2820 num_updated_if_blocks++;
2824 /* Check whether a block is suitable for conditional move conversion.
2825 Every insn must be a simple set of a register to a constant or a
2826 register. For each assignment, store the value in the pointer map
2827 VALS, keyed indexed by register pointer, then store the register
2828 pointer in REGS. COND is the condition we will test. */
2831 check_cond_move_block (basic_block bb,
2832 hash_map<rtx, rtx> *vals,
2837 rtx cc = cc_in_cond (cond);
2839 /* We can only handle simple jumps at the end of the basic block.
2840 It is almost impossible to update the CFG otherwise. */
2842 if (JUMP_P (insn) && !onlyjump_p (insn))
2845 FOR_BB_INSNS (bb, insn)
2849 if (!NONDEBUG_INSN_P (insn) || JUMP_P (insn))
2851 set = single_set (insn);
2855 dest = SET_DEST (set);
2856 src = SET_SRC (set);
2858 || (HARD_REGISTER_P (dest)
2859 && targetm.small_register_classes_for_mode_p (GET_MODE (dest))))
2862 if (!CONSTANT_P (src) && !register_operand (src, VOIDmode))
2865 if (side_effects_p (src) || side_effects_p (dest))
2868 if (may_trap_p (src) || may_trap_p (dest))
2871 /* Don't try to handle this if the source register was
2872 modified earlier in the block. */
2875 || (GET_CODE (src) == SUBREG && REG_P (SUBREG_REG (src))
2876 && vals->get (SUBREG_REG (src))))
2879 /* Don't try to handle this if the destination register was
2880 modified earlier in the block. */
2881 if (vals->get (dest))
2884 /* Don't try to handle this if the condition uses the
2885 destination register. */
2886 if (reg_overlap_mentioned_p (dest, cond))
2889 /* Don't try to handle this if the source register is modified
2890 later in the block. */
2891 if (!CONSTANT_P (src)
2892 && modified_between_p (src, insn, NEXT_INSN (BB_END (bb))))
2895 /* Skip it if the instruction to be moved might clobber CC. */
2896 if (cc && set_of (cc, insn))
2899 vals->put (dest, src);
2901 regs->safe_push (dest);
2907 /* Given a basic block BB suitable for conditional move conversion,
2908 a condition COND, and pointer maps THEN_VALS and ELSE_VALS containing
2909 the register values depending on COND, emit the insns in the block as
2910 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2911 processed. The caller has started a sequence for the conversion.
2912 Return true if successful, false if something goes wrong. */
2915 cond_move_convert_if_block (struct noce_if_info *if_infop,
2916 basic_block bb, rtx cond,
2917 hash_map<rtx, rtx> *then_vals,
2918 hash_map<rtx, rtx> *else_vals,
2923 rtx cond_arg0, cond_arg1;
2925 code = GET_CODE (cond);
2926 cond_arg0 = XEXP (cond, 0);
2927 cond_arg1 = XEXP (cond, 1);
2929 FOR_BB_INSNS (bb, insn)
2931 rtx set, target, dest, t, e;
2933 /* ??? Maybe emit conditional debug insn? */
2934 if (!NONDEBUG_INSN_P (insn) || JUMP_P (insn))
2936 set = single_set (insn);
2937 gcc_assert (set && REG_P (SET_DEST (set)));
2939 dest = SET_DEST (set);
2941 rtx *then_slot = then_vals->get (dest);
2942 rtx *else_slot = else_vals->get (dest);
2943 t = then_slot ? *then_slot : NULL_RTX;
2944 e = else_slot ? *else_slot : NULL_RTX;
2948 /* If this register was set in the then block, we already
2949 handled this case there. */
2962 target = noce_emit_cmove (if_infop, dest, code, cond_arg0, cond_arg1,
2968 noce_emit_move_insn (dest, target);
2974 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2975 it using only conditional moves. Return TRUE if we were successful at
2976 converting the block. */
2979 cond_move_process_if_block (struct noce_if_info *if_info)
2981 basic_block test_bb = if_info->test_bb;
2982 basic_block then_bb = if_info->then_bb;
2983 basic_block else_bb = if_info->else_bb;
2984 basic_block join_bb = if_info->join_bb;
2985 rtx_insn *jump = if_info->jump;
2986 rtx cond = if_info->cond;
2987 rtx_insn *seq, *loc_insn;
2990 vec<rtx> then_regs = vNULL;
2991 vec<rtx> else_regs = vNULL;
2993 int success_p = FALSE;
2995 /* Build a mapping for each block to the value used for each
2997 hash_map<rtx, rtx> then_vals;
2998 hash_map<rtx, rtx> else_vals;
3000 /* Make sure the blocks are suitable. */
3001 if (!check_cond_move_block (then_bb, &then_vals, &then_regs, cond)
3003 && !check_cond_move_block (else_bb, &else_vals, &else_regs, cond)))
3006 /* Make sure the blocks can be used together. If the same register
3007 is set in both blocks, and is not set to a constant in both
3008 cases, then both blocks must set it to the same register. We
3009 have already verified that if it is set to a register, that the
3010 source register does not change after the assignment. Also count
3011 the number of registers set in only one of the blocks. */
3013 FOR_EACH_VEC_ELT (then_regs, i, reg)
3015 rtx *then_slot = then_vals.get (reg);
3016 rtx *else_slot = else_vals.get (reg);
3018 gcc_checking_assert (then_slot);
3023 rtx then_val = *then_slot;
3024 rtx else_val = *else_slot;
3025 if (!CONSTANT_P (then_val) && !CONSTANT_P (else_val)
3026 && !rtx_equal_p (then_val, else_val))
3031 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
3032 FOR_EACH_VEC_ELT (else_regs, i, reg)
3034 gcc_checking_assert (else_vals.get (reg));
3035 if (!then_vals.get (reg))
3039 /* Make sure it is reasonable to convert this block. What matters
3040 is the number of assignments currently made in only one of the
3041 branches, since if we convert we are going to always execute
3043 if (c > MAX_CONDITIONAL_EXECUTE)
3046 /* Try to emit the conditional moves. First do the then block,
3047 then do anything left in the else blocks. */
3049 if (!cond_move_convert_if_block (if_info, then_bb, cond,
3050 &then_vals, &else_vals, false)
3052 && !cond_move_convert_if_block (if_info, else_bb, cond,
3053 &then_vals, &else_vals, true)))
3058 seq = end_ifcvt_sequence (if_info);
3062 loc_insn = first_active_insn (then_bb);
3065 loc_insn = first_active_insn (else_bb);
3066 gcc_assert (loc_insn);
3068 emit_insn_before_setloc (seq, jump, INSN_LOCATION (loc_insn));
3072 delete_basic_block (else_bb);
3076 remove_edge (find_edge (test_bb, join_bb));
3078 remove_edge (find_edge (then_bb, join_bb));
3079 redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb);
3080 delete_basic_block (then_bb);
3083 if (can_merge_blocks_p (test_bb, join_bb))
3085 merge_blocks (test_bb, join_bb);
3089 num_updated_if_blocks++;
3094 then_regs.release ();
3095 else_regs.release ();
3100 /* Determine if a given basic block heads a simple IF-THEN-JOIN or an
3101 IF-THEN-ELSE-JOIN block.
3103 If so, we'll try to convert the insns to not require the branch,
3104 using only transformations that do not require conditional execution.
3106 Return TRUE if we were successful at converting the block. */
3109 noce_find_if_block (basic_block test_bb, edge then_edge, edge else_edge,
3112 basic_block then_bb, else_bb, join_bb;
3113 bool then_else_reversed = false;
3116 rtx_insn *cond_earliest;
3117 struct noce_if_info if_info;
3119 /* We only ever should get here before reload. */
3120 gcc_assert (!reload_completed);
3122 /* Recognize an IF-THEN-ELSE-JOIN block. */
3123 if (single_pred_p (then_edge->dest)
3124 && single_succ_p (then_edge->dest)
3125 && single_pred_p (else_edge->dest)
3126 && single_succ_p (else_edge->dest)
3127 && single_succ (then_edge->dest) == single_succ (else_edge->dest))
3129 then_bb = then_edge->dest;
3130 else_bb = else_edge->dest;
3131 join_bb = single_succ (then_bb);
3133 /* Recognize an IF-THEN-JOIN block. */
3134 else if (single_pred_p (then_edge->dest)
3135 && single_succ_p (then_edge->dest)
3136 && single_succ (then_edge->dest) == else_edge->dest)
3138 then_bb = then_edge->dest;
3139 else_bb = NULL_BLOCK;
3140 join_bb = else_edge->dest;
3142 /* Recognize an IF-ELSE-JOIN block. We can have those because the order
3143 of basic blocks in cfglayout mode does not matter, so the fallthrough
3144 edge can go to any basic block (and not just to bb->next_bb, like in
3146 else if (single_pred_p (else_edge->dest)
3147 && single_succ_p (else_edge->dest)
3148 && single_succ (else_edge->dest) == then_edge->dest)
3150 /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
3151 To make this work, we have to invert the THEN and ELSE blocks
3152 and reverse the jump condition. */
3153 then_bb = else_edge->dest;
3154 else_bb = NULL_BLOCK;
3155 join_bb = single_succ (then_bb);
3156 then_else_reversed = true;
3159 /* Not a form we can handle. */
3162 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3163 if (single_succ_edge (then_bb)->flags & EDGE_COMPLEX)
3166 && single_succ_edge (else_bb)->flags & EDGE_COMPLEX)
3169 num_possible_if_blocks++;
3174 "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
3175 (else_bb) ? "-ELSE" : "",
3176 pass, test_bb->index, then_bb->index);
3179 fprintf (dump_file, ", else %d", else_bb->index);
3181 fprintf (dump_file, ", join %d\n", join_bb->index);
3184 /* If the conditional jump is more than just a conditional
3185 jump, then we can not do if-conversion on this block. */
3186 jump = BB_END (test_bb);
3187 if (! onlyjump_p (jump))
3190 /* If this is not a standard conditional jump, we can't parse it. */
3191 cond = noce_get_condition (jump, &cond_earliest, then_else_reversed);
3195 /* We must be comparing objects whose modes imply the size. */
3196 if (GET_MODE (XEXP (cond, 0)) == BLKmode)
3199 /* Initialize an IF_INFO struct to pass around. */
3200 memset (&if_info, 0, sizeof if_info);
3201 if_info.test_bb = test_bb;
3202 if_info.then_bb = then_bb;
3203 if_info.else_bb = else_bb;
3204 if_info.join_bb = join_bb;
3205 if_info.cond = cond;
3206 if_info.cond_earliest = cond_earliest;
3207 if_info.jump = jump;
3208 if_info.then_else_reversed = then_else_reversed;
3209 if_info.branch_cost = BRANCH_COST (optimize_bb_for_speed_p (test_bb),
3210 predictable_edge_p (then_edge));
3212 /* Do the real work. */
3214 if (noce_process_if_block (&if_info))
3217 if (HAVE_conditional_move
3218 && cond_move_process_if_block (&if_info))
3225 /* Merge the blocks and mark for local life update. */
3228 merge_if_block (struct ce_if_block * ce_info)
3230 basic_block test_bb = ce_info->test_bb; /* last test block */
3231 basic_block then_bb = ce_info->then_bb; /* THEN */
3232 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
3233 basic_block join_bb = ce_info->join_bb; /* join block */
3234 basic_block combo_bb;
3236 /* All block merging is done into the lower block numbers. */
3239 df_set_bb_dirty (test_bb);
3241 /* Merge any basic blocks to handle && and || subtests. Each of
3242 the blocks are on the fallthru path from the predecessor block. */
3243 if (ce_info->num_multiple_test_blocks > 0)
3245 basic_block bb = test_bb;
3246 basic_block last_test_bb = ce_info->last_test_bb;
3247 basic_block fallthru = block_fallthru (bb);
3252 fallthru = block_fallthru (bb);
3253 merge_blocks (combo_bb, bb);
3256 while (bb != last_test_bb);
3259 /* Merge TEST block into THEN block. Normally the THEN block won't have a
3260 label, but it might if there were || tests. That label's count should be
3261 zero, and it normally should be removed. */
3265 /* If THEN_BB has no successors, then there's a BARRIER after it.
3266 If COMBO_BB has more than one successor (THEN_BB), then that BARRIER
3267 is no longer needed, and in fact it is incorrect to leave it in
3269 if (EDGE_COUNT (then_bb->succs) == 0
3270 && EDGE_COUNT (combo_bb->succs) > 1)
3272 rtx_insn *end = NEXT_INSN (BB_END (then_bb));
3273 while (end && NOTE_P (end) && !NOTE_INSN_BASIC_BLOCK_P (end))
3274 end = NEXT_INSN (end);
3276 if (end && BARRIER_P (end))
3279 merge_blocks (combo_bb, then_bb);
3283 /* The ELSE block, if it existed, had a label. That label count
3284 will almost always be zero, but odd things can happen when labels
3285 get their addresses taken. */
3288 /* If ELSE_BB has no successors, then there's a BARRIER after it.
3289 If COMBO_BB has more than one successor (ELSE_BB), then that BARRIER
3290 is no longer needed, and in fact it is incorrect to leave it in
3292 if (EDGE_COUNT (else_bb->succs) == 0
3293 && EDGE_COUNT (combo_bb->succs) > 1)
3295 rtx_insn *end = NEXT_INSN (BB_END (else_bb));
3296 while (end && NOTE_P (end) && !NOTE_INSN_BASIC_BLOCK_P (end))
3297 end = NEXT_INSN (end);
3299 if (end && BARRIER_P (end))
3302 merge_blocks (combo_bb, else_bb);
3306 /* If there was no join block reported, that means it was not adjacent
3307 to the others, and so we cannot merge them. */
3311 rtx_insn *last = BB_END (combo_bb);
3313 /* The outgoing edge for the current COMBO block should already
3314 be correct. Verify this. */
3315 if (EDGE_COUNT (combo_bb->succs) == 0)
3316 gcc_assert (find_reg_note (last, REG_NORETURN, NULL)
3317 || (NONJUMP_INSN_P (last)
3318 && GET_CODE (PATTERN (last)) == TRAP_IF
3319 && (TRAP_CONDITION (PATTERN (last))
3320 == const_true_rtx)));
3323 /* There should still be something at the end of the THEN or ELSE
3324 blocks taking us to our final destination. */
3325 gcc_assert (JUMP_P (last)
3326 || (EDGE_SUCC (combo_bb, 0)->dest
3327 == EXIT_BLOCK_PTR_FOR_FN (cfun)
3329 && SIBLING_CALL_P (last))
3330 || ((EDGE_SUCC (combo_bb, 0)->flags & EDGE_EH)
3331 && can_throw_internal (last)));
3334 /* The JOIN block may have had quite a number of other predecessors too.
3335 Since we've already merged the TEST, THEN and ELSE blocks, we should
3336 have only one remaining edge from our if-then-else diamond. If there
3337 is more than one remaining edge, it must come from elsewhere. There
3338 may be zero incoming edges if the THEN block didn't actually join
3339 back up (as with a call to a non-return function). */
3340 else if (EDGE_COUNT (join_bb->preds) < 2
3341 && join_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
3343 /* We can merge the JOIN cleanly and update the dataflow try
3344 again on this pass.*/
3345 merge_blocks (combo_bb, join_bb);
3350 /* We cannot merge the JOIN. */
3352 /* The outgoing edge for the current COMBO block should already
3353 be correct. Verify this. */
3354 gcc_assert (single_succ_p (combo_bb)
3355 && single_succ (combo_bb) == join_bb);
3357 /* Remove the jump and cruft from the end of the COMBO block. */
3358 if (join_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
3359 tidy_fallthru_edge (single_succ_edge (combo_bb));
3362 num_updated_if_blocks++;
3365 /* Find a block ending in a simple IF condition and try to transform it
3366 in some way. When converting a multi-block condition, put the new code
3367 in the first such block and delete the rest. Return a pointer to this
3368 first block if some transformation was done. Return NULL otherwise. */
3371 find_if_header (basic_block test_bb, int pass)
3373 ce_if_block ce_info;
3377 /* The kind of block we're looking for has exactly two successors. */
3378 if (EDGE_COUNT (test_bb->succs) != 2)
3381 then_edge = EDGE_SUCC (test_bb, 0);
3382 else_edge = EDGE_SUCC (test_bb, 1);
3384 if (df_get_bb_dirty (then_edge->dest))
3386 if (df_get_bb_dirty (else_edge->dest))
3389 /* Neither edge should be abnormal. */
3390 if ((then_edge->flags & EDGE_COMPLEX)
3391 || (else_edge->flags & EDGE_COMPLEX))
3394 /* Nor exit the loop. */
3395 if ((then_edge->flags & EDGE_LOOP_EXIT)
3396 || (else_edge->flags & EDGE_LOOP_EXIT))
3399 /* The THEN edge is canonically the one that falls through. */
3400 if (then_edge->flags & EDGE_FALLTHRU)
3402 else if (else_edge->flags & EDGE_FALLTHRU)
3405 else_edge = then_edge;
3409 /* Otherwise this must be a multiway branch of some sort. */
3412 memset (&ce_info, 0, sizeof (ce_info));
3413 ce_info.test_bb = test_bb;
3414 ce_info.then_bb = then_edge->dest;
3415 ce_info.else_bb = else_edge->dest;
3416 ce_info.pass = pass;
3418 #ifdef IFCVT_MACHDEP_INIT
3419 IFCVT_MACHDEP_INIT (&ce_info);
3422 if (!reload_completed
3423 && noce_find_if_block (test_bb, then_edge, else_edge, pass))
3426 if (reload_completed
3427 && targetm.have_conditional_execution ()
3428 && cond_exec_find_if_block (&ce_info))
3432 && optab_handler (ctrap_optab, word_mode) != CODE_FOR_nothing
3433 && find_cond_trap (test_bb, then_edge, else_edge))
3436 if (dom_info_state (CDI_POST_DOMINATORS) >= DOM_NO_FAST_QUERY
3437 && (reload_completed || !targetm.have_conditional_execution ()))
3439 if (find_if_case_1 (test_bb, then_edge, else_edge))
3441 if (find_if_case_2 (test_bb, then_edge, else_edge))
3449 fprintf (dump_file, "Conversion succeeded on pass %d.\n", pass);
3450 /* Set this so we continue looking. */
3451 cond_exec_changed_p = TRUE;
3452 return ce_info.test_bb;
3455 /* Return true if a block has two edges, one of which falls through to the next
3456 block, and the other jumps to a specific block, so that we can tell if the
3457 block is part of an && test or an || test. Returns either -1 or the number
3458 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
3461 block_jumps_and_fallthru_p (basic_block cur_bb, basic_block target_bb)
3464 int fallthru_p = FALSE;
3471 if (!cur_bb || !target_bb)
3474 /* If no edges, obviously it doesn't jump or fallthru. */
3475 if (EDGE_COUNT (cur_bb->succs) == 0)
3478 FOR_EACH_EDGE (cur_edge, ei, cur_bb->succs)
3480 if (cur_edge->flags & EDGE_COMPLEX)
3481 /* Anything complex isn't what we want. */
3484 else if (cur_edge->flags & EDGE_FALLTHRU)
3487 else if (cur_edge->dest == target_bb)
3494 if ((jump_p & fallthru_p) == 0)
3497 /* Don't allow calls in the block, since this is used to group && and ||
3498 together for conditional execution support. ??? we should support
3499 conditional execution support across calls for IA-64 some day, but
3500 for now it makes the code simpler. */
3501 end = BB_END (cur_bb);
3502 insn = BB_HEAD (cur_bb);
3504 while (insn != NULL_RTX)
3511 && !DEBUG_INSN_P (insn)
3512 && GET_CODE (PATTERN (insn)) != USE
3513 && GET_CODE (PATTERN (insn)) != CLOBBER)
3519 insn = NEXT_INSN (insn);
3525 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3526 block. If so, we'll try to convert the insns to not require the branch.
3527 Return TRUE if we were successful at converting the block. */
3530 cond_exec_find_if_block (struct ce_if_block * ce_info)
3532 basic_block test_bb = ce_info->test_bb;
3533 basic_block then_bb = ce_info->then_bb;
3534 basic_block else_bb = ce_info->else_bb;
3535 basic_block join_bb = NULL_BLOCK;
3540 ce_info->last_test_bb = test_bb;
3542 /* We only ever should get here after reload,
3543 and if we have conditional execution. */
3544 gcc_assert (reload_completed && targetm.have_conditional_execution ());
3546 /* Discover if any fall through predecessors of the current test basic block
3547 were && tests (which jump to the else block) or || tests (which jump to
3549 if (single_pred_p (test_bb)
3550 && single_pred_edge (test_bb)->flags == EDGE_FALLTHRU)
3552 basic_block bb = single_pred (test_bb);
3553 basic_block target_bb;
3554 int max_insns = MAX_CONDITIONAL_EXECUTE;
3557 /* Determine if the preceding block is an && or || block. */
3558 if ((n_insns = block_jumps_and_fallthru_p (bb, else_bb)) >= 0)
3560 ce_info->and_and_p = TRUE;
3561 target_bb = else_bb;
3563 else if ((n_insns = block_jumps_and_fallthru_p (bb, then_bb)) >= 0)
3565 ce_info->and_and_p = FALSE;
3566 target_bb = then_bb;
3569 target_bb = NULL_BLOCK;
3571 if (target_bb && n_insns <= max_insns)
3573 int total_insns = 0;
3576 ce_info->last_test_bb = test_bb;
3578 /* Found at least one && or || block, look for more. */
3581 ce_info->test_bb = test_bb = bb;
3582 total_insns += n_insns;
3585 if (!single_pred_p (bb))
3588 bb = single_pred (bb);
3589 n_insns = block_jumps_and_fallthru_p (bb, target_bb);
3591 while (n_insns >= 0 && (total_insns + n_insns) <= max_insns);
3593 ce_info->num_multiple_test_blocks = blocks;
3594 ce_info->num_multiple_test_insns = total_insns;
3596 if (ce_info->and_and_p)
3597 ce_info->num_and_and_blocks = blocks;
3599 ce_info->num_or_or_blocks = blocks;
3603 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3604 other than any || blocks which jump to the THEN block. */
3605 if ((EDGE_COUNT (then_bb->preds) - ce_info->num_or_or_blocks) != 1)
3608 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3609 FOR_EACH_EDGE (cur_edge, ei, then_bb->preds)
3611 if (cur_edge->flags & EDGE_COMPLEX)
3615 FOR_EACH_EDGE (cur_edge, ei, else_bb->preds)
3617 if (cur_edge->flags & EDGE_COMPLEX)
3621 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3622 if (EDGE_COUNT (then_bb->succs) > 0
3623 && (!single_succ_p (then_bb)
3624 || (single_succ_edge (then_bb)->flags & EDGE_COMPLEX)
3625 || (epilogue_completed
3626 && tablejump_p (BB_END (then_bb), NULL, NULL))))
3629 /* If the THEN block has no successors, conditional execution can still
3630 make a conditional call. Don't do this unless the ELSE block has
3631 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3632 Check for the last insn of the THEN block being an indirect jump, which
3633 is listed as not having any successors, but confuses the rest of the CE
3634 code processing. ??? we should fix this in the future. */
3635 if (EDGE_COUNT (then_bb->succs) == 0)
3637 if (single_pred_p (else_bb) && else_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
3639 rtx_insn *last_insn = BB_END (then_bb);
3642 && NOTE_P (last_insn)
3643 && last_insn != BB_HEAD (then_bb))
3644 last_insn = PREV_INSN (last_insn);
3647 && JUMP_P (last_insn)
3648 && ! simplejump_p (last_insn))
3652 else_bb = NULL_BLOCK;
3658 /* If the THEN block's successor is the other edge out of the TEST block,
3659 then we have an IF-THEN combo without an ELSE. */
3660 else if (single_succ (then_bb) == else_bb)
3663 else_bb = NULL_BLOCK;
3666 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3667 has exactly one predecessor and one successor, and the outgoing edge
3668 is not complex, then we have an IF-THEN-ELSE combo. */
3669 else if (single_succ_p (else_bb)
3670 && single_succ (then_bb) == single_succ (else_bb)
3671 && single_pred_p (else_bb)
3672 && !(single_succ_edge (else_bb)->flags & EDGE_COMPLEX)
3673 && !(epilogue_completed
3674 && tablejump_p (BB_END (else_bb), NULL, NULL)))
3675 join_bb = single_succ (else_bb);
3677 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3681 num_possible_if_blocks++;
3686 "\nIF-THEN%s block found, pass %d, start block %d "
3687 "[insn %d], then %d [%d]",
3688 (else_bb) ? "-ELSE" : "",
3691 BB_HEAD (test_bb) ? (int)INSN_UID (BB_HEAD (test_bb)) : -1,
3693 BB_HEAD (then_bb) ? (int)INSN_UID (BB_HEAD (then_bb)) : -1);
3696 fprintf (dump_file, ", else %d [%d]",
3698 BB_HEAD (else_bb) ? (int)INSN_UID (BB_HEAD (else_bb)) : -1);
3700 fprintf (dump_file, ", join %d [%d]",
3702 BB_HEAD (join_bb) ? (int)INSN_UID (BB_HEAD (join_bb)) : -1);
3704 if (ce_info->num_multiple_test_blocks > 0)
3705 fprintf (dump_file, ", %d %s block%s last test %d [%d]",
3706 ce_info->num_multiple_test_blocks,
3707 (ce_info->and_and_p) ? "&&" : "||",
3708 (ce_info->num_multiple_test_blocks == 1) ? "" : "s",
3709 ce_info->last_test_bb->index,
3710 ((BB_HEAD (ce_info->last_test_bb))
3711 ? (int)INSN_UID (BB_HEAD (ce_info->last_test_bb))
3714 fputc ('\n', dump_file);
3717 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3718 first condition for free, since we've already asserted that there's a
3719 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3720 we checked the FALLTHRU flag, those are already adjacent to the last IF
3722 /* ??? As an enhancement, move the ELSE block. Have to deal with
3723 BLOCK notes, if by no other means than backing out the merge if they
3724 exist. Sticky enough I don't want to think about it now. */
3726 if (else_bb && (next = next->next_bb) != else_bb)
3728 if ((next = next->next_bb) != join_bb
3729 && join_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
3737 /* Do the real work. */
3739 ce_info->else_bb = else_bb;
3740 ce_info->join_bb = join_bb;
3742 /* If we have && and || tests, try to first handle combining the && and ||
3743 tests into the conditional code, and if that fails, go back and handle
3744 it without the && and ||, which at present handles the && case if there
3745 was no ELSE block. */
3746 if (cond_exec_process_if_block (ce_info, TRUE))
3749 if (ce_info->num_multiple_test_blocks)
3753 if (cond_exec_process_if_block (ce_info, FALSE))
3760 /* Convert a branch over a trap, or a branch
3761 to a trap, into a conditional trap. */
3764 find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge)
3766 basic_block then_bb = then_edge->dest;
3767 basic_block else_bb = else_edge->dest;
3768 basic_block other_bb, trap_bb;
3769 rtx_insn *trap, *jump;
3771 rtx_insn *cond_earliest;
3774 /* Locate the block with the trap instruction. */
3775 /* ??? While we look for no successors, we really ought to allow
3776 EH successors. Need to fix merge_if_block for that to work. */
3777 if ((trap = block_has_only_trap (then_bb)) != NULL)
3778 trap_bb = then_bb, other_bb = else_bb;
3779 else if ((trap = block_has_only_trap (else_bb)) != NULL)
3780 trap_bb = else_bb, other_bb = then_bb;
3786 fprintf (dump_file, "\nTRAP-IF block found, start %d, trap %d\n",
3787 test_bb->index, trap_bb->index);
3790 /* If this is not a standard conditional jump, we can't parse it. */
3791 jump = BB_END (test_bb);
3792 cond = noce_get_condition (jump, &cond_earliest, false);
3796 /* If the conditional jump is more than just a conditional jump, then
3797 we can not do if-conversion on this block. */
3798 if (! onlyjump_p (jump))
3801 /* We must be comparing objects whose modes imply the size. */
3802 if (GET_MODE (XEXP (cond, 0)) == BLKmode)
3805 /* Reverse the comparison code, if necessary. */
3806 code = GET_CODE (cond);
3807 if (then_bb == trap_bb)
3809 code = reversed_comparison_code (cond, jump);
3810 if (code == UNKNOWN)
3814 /* Attempt to generate the conditional trap. */
3815 seq = gen_cond_trap (code, copy_rtx (XEXP (cond, 0)),
3816 copy_rtx (XEXP (cond, 1)),
3817 TRAP_CODE (PATTERN (trap)));
3821 /* Emit the new insns before cond_earliest. */
3822 emit_insn_before_setloc (seq, cond_earliest, INSN_LOCATION (trap));
3824 /* Delete the trap block if possible. */
3825 remove_edge (trap_bb == then_bb ? then_edge : else_edge);
3826 df_set_bb_dirty (test_bb);
3827 df_set_bb_dirty (then_bb);
3828 df_set_bb_dirty (else_bb);
3830 if (EDGE_COUNT (trap_bb->preds) == 0)
3832 delete_basic_block (trap_bb);
3836 /* Wire together the blocks again. */
3837 if (current_ir_type () == IR_RTL_CFGLAYOUT)
3838 single_succ_edge (test_bb)->flags |= EDGE_FALLTHRU;
3839 else if (trap_bb == then_bb)
3844 lab = JUMP_LABEL (jump);
3845 newjump = emit_jump_insn_after (gen_jump (lab), jump);
3846 LABEL_NUSES (lab) += 1;
3847 JUMP_LABEL (newjump) = lab;
3848 emit_barrier_after (newjump);
3852 if (can_merge_blocks_p (test_bb, other_bb))
3854 merge_blocks (test_bb, other_bb);
3858 num_updated_if_blocks++;
3862 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3866 block_has_only_trap (basic_block bb)
3870 /* We're not the exit block. */
3871 if (bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
3874 /* The block must have no successors. */
3875 if (EDGE_COUNT (bb->succs) > 0)
3878 /* The only instruction in the THEN block must be the trap. */
3879 trap = first_active_insn (bb);
3880 if (! (trap == BB_END (bb)
3881 && GET_CODE (PATTERN (trap)) == TRAP_IF
3882 && TRAP_CONDITION (PATTERN (trap)) == const_true_rtx))
3888 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3889 transformable, but not necessarily the other. There need be no
3892 Return TRUE if we were successful at converting the block.
3894 Cases we'd like to look at:
3897 if (test) goto over; // x not live
3905 if (! test) goto label;
3908 if (test) goto E; // x not live
3922 (3) // This one's really only interesting for targets that can do
3923 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3924 // it results in multiple branches on a cache line, which often
3925 // does not sit well with predictors.
3927 if (test1) goto E; // predicted not taken
3943 (A) Don't do (2) if the branch is predicted against the block we're
3944 eliminating. Do it anyway if we can eliminate a branch; this requires
3945 that the sole successor of the eliminated block postdominate the other
3948 (B) With CE, on (3) we can steal from both sides of the if, creating
3957 Again, this is most useful if J postdominates.
3959 (C) CE substitutes for helpful life information.
3961 (D) These heuristics need a lot of work. */
3963 /* Tests for case 1 above. */
3966 find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
3968 basic_block then_bb = then_edge->dest;
3969 basic_block else_bb = else_edge->dest;
3971 int then_bb_index, then_prob;
3972 rtx else_target = NULL_RTX;
3974 /* If we are partitioning hot/cold basic blocks, we don't want to
3975 mess up unconditional or indirect jumps that cross between hot
3978 Basic block partitioning may result in some jumps that appear to
3979 be optimizable (or blocks that appear to be mergeable), but which really
3980 must be left untouched (they are required to make it safely across
3981 partition boundaries). See the comments at the top of
3982 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3984 if ((BB_END (then_bb)
3985 && JUMP_P (BB_END (then_bb))
3986 && CROSSING_JUMP_P (BB_END (then_bb)))
3987 || (BB_END (test_bb)
3988 && JUMP_P (BB_END (test_bb))
3989 && CROSSING_JUMP_P (BB_END (test_bb)))
3990 || (BB_END (else_bb)
3991 && JUMP_P (BB_END (else_bb))
3992 && CROSSING_JUMP_P (BB_END (else_bb))))
3995 /* THEN has one successor. */
3996 if (!single_succ_p (then_bb))
3999 /* THEN does not fall through, but is not strange either. */
4000 if (single_succ_edge (then_bb)->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))
4003 /* THEN has one predecessor. */
4004 if (!single_pred_p (then_bb))
4007 /* THEN must do something. */
4008 if (forwarder_block_p (then_bb))
4011 num_possible_if_blocks++;
4014 "\nIF-CASE-1 found, start %d, then %d\n",
4015 test_bb->index, then_bb->index);
4017 if (then_edge->probability)
4018 then_prob = REG_BR_PROB_BASE - then_edge->probability;
4020 then_prob = REG_BR_PROB_BASE / 2;
4022 /* We're speculating from the THEN path, we want to make sure the cost
4023 of speculation is within reason. */
4024 if (! cheap_bb_rtx_cost_p (then_bb, then_prob,
4025 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge->src),
4026 predictable_edge_p (then_edge)))))
4029 if (else_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
4031 rtx_insn *jump = BB_END (else_edge->src);
4032 gcc_assert (JUMP_P (jump));
4033 else_target = JUMP_LABEL (jump);
4036 /* Registers set are dead, or are predicable. */
4037 if (! dead_or_predicable (test_bb, then_bb, else_bb,
4038 single_succ_edge (then_bb), 1))
4041 /* Conversion went ok, including moving the insns and fixing up the
4042 jump. Adjust the CFG to match. */
4044 /* We can avoid creating a new basic block if then_bb is immediately
4045 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
4046 through to else_bb. */
4048 if (then_bb->next_bb == else_bb
4049 && then_bb->prev_bb == test_bb
4050 && else_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
4052 redirect_edge_succ (FALLTHRU_EDGE (test_bb), else_bb);
4055 else if (else_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
4056 new_bb = force_nonfallthru_and_redirect (FALLTHRU_EDGE (test_bb),
4057 else_bb, else_target);
4059 new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb),
4062 df_set_bb_dirty (test_bb);
4063 df_set_bb_dirty (else_bb);
4065 then_bb_index = then_bb->index;
4066 delete_basic_block (then_bb);
4068 /* Make rest of code believe that the newly created block is the THEN_BB
4069 block we removed. */
4072 df_bb_replace (then_bb_index, new_bb);
4073 /* This should have been done above via force_nonfallthru_and_redirect
4074 (possibly called from redirect_edge_and_branch_force). */
4075 gcc_checking_assert (BB_PARTITION (new_bb) == BB_PARTITION (test_bb));
4079 num_updated_if_blocks++;
4084 /* Test for case 2 above. */
4087 find_if_case_2 (basic_block test_bb, edge then_edge, edge else_edge)
4089 basic_block then_bb = then_edge->dest;
4090 basic_block else_bb = else_edge->dest;
4092 int then_prob, else_prob;
4094 /* We do not want to speculate (empty) loop latches. */
4096 && else_bb->loop_father->latch == else_bb)
4099 /* If we are partitioning hot/cold basic blocks, we don't want to
4100 mess up unconditional or indirect jumps that cross between hot
4103 Basic block partitioning may result in some jumps that appear to
4104 be optimizable (or blocks that appear to be mergeable), but which really
4105 must be left untouched (they are required to make it safely across
4106 partition boundaries). See the comments at the top of
4107 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4109 if ((BB_END (then_bb)
4110 && JUMP_P (BB_END (then_bb))
4111 && CROSSING_JUMP_P (BB_END (then_bb)))
4112 || (BB_END (test_bb)
4113 && JUMP_P (BB_END (test_bb))
4114 && CROSSING_JUMP_P (BB_END (test_bb)))
4115 || (BB_END (else_bb)
4116 && JUMP_P (BB_END (else_bb))
4117 && CROSSING_JUMP_P (BB_END (else_bb))))
4120 /* ELSE has one successor. */
4121 if (!single_succ_p (else_bb))
4124 else_succ = single_succ_edge (else_bb);
4126 /* ELSE outgoing edge is not complex. */
4127 if (else_succ->flags & EDGE_COMPLEX)
4130 /* ELSE has one predecessor. */
4131 if (!single_pred_p (else_bb))
4134 /* THEN is not EXIT. */
4135 if (then_bb->index < NUM_FIXED_BLOCKS)
4138 if (else_edge->probability)
4140 else_prob = else_edge->probability;
4141 then_prob = REG_BR_PROB_BASE - else_prob;
4145 else_prob = REG_BR_PROB_BASE / 2;
4146 then_prob = REG_BR_PROB_BASE / 2;
4149 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
4150 if (else_prob > then_prob)
4152 else if (else_succ->dest->index < NUM_FIXED_BLOCKS
4153 || dominated_by_p (CDI_POST_DOMINATORS, then_bb,
4159 num_possible_if_blocks++;
4162 "\nIF-CASE-2 found, start %d, else %d\n",
4163 test_bb->index, else_bb->index);
4165 /* We're speculating from the ELSE path, we want to make sure the cost
4166 of speculation is within reason. */
4167 if (! cheap_bb_rtx_cost_p (else_bb, else_prob,
4168 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge->src),
4169 predictable_edge_p (else_edge)))))
4172 /* Registers set are dead, or are predicable. */
4173 if (! dead_or_predicable (test_bb, else_bb, then_bb, else_succ, 0))
4176 /* Conversion went ok, including moving the insns and fixing up the
4177 jump. Adjust the CFG to match. */
4179 df_set_bb_dirty (test_bb);
4180 df_set_bb_dirty (then_bb);
4181 delete_basic_block (else_bb);
4184 num_updated_if_blocks++;
4186 /* ??? We may now fallthru from one of THEN's successors into a join
4187 block. Rerun cleanup_cfg? Examine things manually? Wait? */
4192 /* Used by the code above to perform the actual rtl transformations.
4193 Return TRUE if successful.
4195 TEST_BB is the block containing the conditional branch. MERGE_BB
4196 is the block containing the code to manipulate. DEST_EDGE is an
4197 edge representing a jump to the join block; after the conversion,
4198 TEST_BB should be branching to its destination.
4199 REVERSEP is true if the sense of the branch should be reversed. */
4202 dead_or_predicable (basic_block test_bb, basic_block merge_bb,
4203 basic_block other_bb, edge dest_edge, int reversep)
4205 basic_block new_dest = dest_edge->dest;
4206 rtx_insn *head, *end, *jump;
4207 rtx_insn *earliest = NULL;
4209 bitmap merge_set = NULL;
4210 /* Number of pending changes. */
4211 int n_validated_changes = 0;
4212 rtx new_dest_label = NULL_RTX;
4214 jump = BB_END (test_bb);
4216 /* Find the extent of the real code in the merge block. */
4217 head = BB_HEAD (merge_bb);
4218 end = BB_END (merge_bb);
4220 while (DEBUG_INSN_P (end) && end != head)
4221 end = PREV_INSN (end);
4223 /* If merge_bb ends with a tablejump, predicating/moving insn's
4224 into test_bb and then deleting merge_bb will result in the jumptable
4225 that follows merge_bb being removed along with merge_bb and then we
4226 get an unresolved reference to the jumptable. */
4227 if (tablejump_p (end, NULL, NULL))
4231 head = NEXT_INSN (head);
4232 while (DEBUG_INSN_P (head) && head != end)
4233 head = NEXT_INSN (head);
4241 head = NEXT_INSN (head);
4242 while (DEBUG_INSN_P (head) && head != end)
4243 head = NEXT_INSN (head);
4248 if (!onlyjump_p (end))
4255 end = PREV_INSN (end);
4256 while (DEBUG_INSN_P (end) && end != head)
4257 end = PREV_INSN (end);
4260 /* Don't move frame-related insn across the conditional branch. This
4261 can lead to one of the paths of the branch having wrong unwind info. */
4262 if (epilogue_completed)
4264 rtx_insn *insn = head;
4267 if (INSN_P (insn) && RTX_FRAME_RELATED_P (insn))
4271 insn = NEXT_INSN (insn);
4275 /* Disable handling dead code by conditional execution if the machine needs
4276 to do anything funny with the tests, etc. */
4277 #ifndef IFCVT_MODIFY_TESTS
4278 if (targetm.have_conditional_execution ())
4280 /* In the conditional execution case, we have things easy. We know
4281 the condition is reversible. We don't have to check life info
4282 because we're going to conditionally execute the code anyway.
4283 All that's left is making sure the insns involved can actually
4288 cond = cond_exec_get_condition (jump);
4292 rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
4293 int prob_val = (note ? XINT (note, 0) : -1);
4297 enum rtx_code rev = reversed_comparison_code (cond, jump);
4300 cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
4303 prob_val = REG_BR_PROB_BASE - prob_val;
4306 if (cond_exec_process_insns (NULL, head, end, cond, prob_val, 0)
4307 && verify_changes (0))
4308 n_validated_changes = num_validated_changes ();
4316 /* If we allocated new pseudos (e.g. in the conditional move
4317 expander called from noce_emit_cmove), we must resize the
4319 if (max_regno < max_reg_num ())
4320 max_regno = max_reg_num ();
4322 /* Try the NCE path if the CE path did not result in any changes. */
4323 if (n_validated_changes == 0)
4330 /* In the non-conditional execution case, we have to verify that there
4331 are no trapping operations, no calls, no references to memory, and
4332 that any registers modified are dead at the branch site. */
4334 if (!any_condjump_p (jump))
4337 /* Find the extent of the conditional. */
4338 cond = noce_get_condition (jump, &earliest, false);
4342 live = BITMAP_ALLOC (®_obstack);
4343 simulate_backwards_to_point (merge_bb, live, end);
4344 success = can_move_insns_across (head, end, earliest, jump,
4346 df_get_live_in (other_bb), NULL);
4351 /* Collect the set of registers set in MERGE_BB. */
4352 merge_set = BITMAP_ALLOC (®_obstack);
4354 FOR_BB_INSNS (merge_bb, insn)
4355 if (NONDEBUG_INSN_P (insn))
4356 df_simulate_find_defs (insn, merge_set);
4358 /* If shrink-wrapping, disable this optimization when test_bb is
4359 the first basic block and merge_bb exits. The idea is to not
4360 move code setting up a return register as that may clobber a
4361 register used to pass function parameters, which then must be
4362 saved in caller-saved regs. A caller-saved reg requires the
4363 prologue, killing a shrink-wrap opportunity. */
4364 if ((SHRINK_WRAPPING_ENABLED && !epilogue_completed)
4365 && ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb == test_bb
4366 && single_succ_p (new_dest)
4367 && single_succ (new_dest) == EXIT_BLOCK_PTR_FOR_FN (cfun)
4368 && bitmap_intersect_p (df_get_live_in (new_dest), merge_set))
4373 return_regs = BITMAP_ALLOC (®_obstack);
4375 /* Start off with the intersection of regs used to pass
4376 params and regs used to return values. */
4377 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4378 if (FUNCTION_ARG_REGNO_P (i)
4379 && targetm.calls.function_value_regno_p (i))
4380 bitmap_set_bit (return_regs, INCOMING_REGNO (i));
4382 bitmap_and_into (return_regs,
4383 df_get_live_out (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
4384 bitmap_and_into (return_regs,
4385 df_get_live_in (EXIT_BLOCK_PTR_FOR_FN (cfun)));
4386 if (!bitmap_empty_p (return_regs))
4388 FOR_BB_INSNS_REVERSE (new_dest, insn)
4389 if (NONDEBUG_INSN_P (insn))
4393 /* If this insn sets any reg in return_regs, add all
4394 reg uses to the set of regs we're interested in. */
4395 FOR_EACH_INSN_DEF (def, insn)
4396 if (bitmap_bit_p (return_regs, DF_REF_REGNO (def)))
4398 df_simulate_uses (insn, return_regs);
4402 if (bitmap_intersect_p (merge_set, return_regs))
4404 BITMAP_FREE (return_regs);
4405 BITMAP_FREE (merge_set);
4409 BITMAP_FREE (return_regs);
4414 /* We don't want to use normal invert_jump or redirect_jump because
4415 we don't want to delete_insn called. Also, we want to do our own
4416 change group management. */
4418 old_dest = JUMP_LABEL (jump);
4419 if (other_bb != new_dest)
4421 if (!any_condjump_p (jump))
4424 if (JUMP_P (BB_END (dest_edge->src)))
4425 new_dest_label = JUMP_LABEL (BB_END (dest_edge->src));
4426 else if (new_dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
4427 new_dest_label = ret_rtx;
4429 new_dest_label = block_label (new_dest);
4431 rtx_jump_insn *jump_insn = as_a <rtx_jump_insn *> (jump);
4433 ? ! invert_jump_1 (jump_insn, new_dest_label)
4434 : ! redirect_jump_1 (jump_insn, new_dest_label))
4438 if (verify_changes (n_validated_changes))
4439 confirm_change_group ();
4443 if (other_bb != new_dest)
4445 redirect_jump_2 (as_a <rtx_jump_insn *> (jump), old_dest, new_dest_label,
4448 redirect_edge_succ (BRANCH_EDGE (test_bb), new_dest);
4451 std::swap (BRANCH_EDGE (test_bb)->count,
4452 FALLTHRU_EDGE (test_bb)->count);
4453 std::swap (BRANCH_EDGE (test_bb)->probability,
4454 FALLTHRU_EDGE (test_bb)->probability);
4455 update_br_prob_note (test_bb);
4459 /* Move the insns out of MERGE_BB to before the branch. */
4464 if (end == BB_END (merge_bb))
4465 BB_END (merge_bb) = PREV_INSN (head);
4467 /* PR 21767: when moving insns above a conditional branch, the REG_EQUAL
4468 notes being moved might become invalid. */
4474 if (! INSN_P (insn))
4476 note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
4479 remove_note (insn, note);
4480 } while (insn != end && (insn = NEXT_INSN (insn)));
4482 /* PR46315: when moving insns above a conditional branch, the REG_EQUAL
4483 notes referring to the registers being set might become invalid. */
4489 EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
4490 remove_reg_equal_equiv_notes_for_regno (i);
4492 BITMAP_FREE (merge_set);
4495 reorder_insns (head, end, PREV_INSN (earliest));
4498 /* Remove the jump and edge if we can. */
4499 if (other_bb == new_dest)
4502 remove_edge (BRANCH_EDGE (test_bb));
4503 /* ??? Can't merge blocks here, as then_bb is still in use.
4504 At minimum, the merge will get done just before bb-reorder. */
4513 BITMAP_FREE (merge_set);
4518 /* Main entry point for all if-conversion. AFTER_COMBINE is true if
4519 we are after combine pass. */
4522 if_convert (bool after_combine)
4529 df_live_add_problem ();
4530 df_live_set_all_dirty ();
4533 /* Record whether we are after combine pass. */
4534 ifcvt_after_combine = after_combine;
4535 num_possible_if_blocks = 0;
4536 num_updated_if_blocks = 0;
4537 num_true_changes = 0;
4539 loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
4540 mark_loop_exit_edges ();
4541 loop_optimizer_finalize ();
4542 free_dominance_info (CDI_DOMINATORS);
4544 /* Compute postdominators. */
4545 calculate_dominance_info (CDI_POST_DOMINATORS);
4547 df_set_flags (DF_LR_RUN_DCE);
4549 /* Go through each of the basic blocks looking for things to convert. If we
4550 have conditional execution, we make multiple passes to allow us to handle
4551 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
4556 /* Only need to do dce on the first pass. */
4557 df_clear_flags (DF_LR_RUN_DCE);
4558 cond_exec_changed_p = FALSE;
4561 #ifdef IFCVT_MULTIPLE_DUMPS
4562 if (dump_file && pass > 1)
4563 fprintf (dump_file, "\n\n========== Pass %d ==========\n", pass);
4566 FOR_EACH_BB_FN (bb, cfun)
4569 while (!df_get_bb_dirty (bb)
4570 && (new_bb = find_if_header (bb, pass)) != NULL)
4574 #ifdef IFCVT_MULTIPLE_DUMPS
4575 if (dump_file && cond_exec_changed_p)
4576 print_rtl_with_bb (dump_file, get_insns (), dump_flags);
4579 while (cond_exec_changed_p);
4581 #ifdef IFCVT_MULTIPLE_DUMPS
4583 fprintf (dump_file, "\n\n========== no more changes\n");
4586 free_dominance_info (CDI_POST_DOMINATORS);
4591 clear_aux_for_blocks ();
4593 /* If we allocated new pseudos, we must resize the array for sched1. */
4594 if (max_regno < max_reg_num ())
4595 max_regno = max_reg_num ();
4597 /* Write the final stats. */
4598 if (dump_file && num_possible_if_blocks > 0)
4601 "\n%d possible IF blocks searched.\n",
4602 num_possible_if_blocks);
4604 "%d IF blocks converted.\n",
4605 num_updated_if_blocks);
4607 "%d true changes made.\n\n\n",
4612 df_remove_problem (df_live);
4614 #ifdef ENABLE_CHECKING
4615 verify_flow_info ();
4619 /* If-conversion and CFG cleanup. */
4621 rest_of_handle_if_conversion (void)
4623 if (flag_if_conversion)
4627 dump_reg_info (dump_file);
4628 dump_flow_info (dump_file, dump_flags);
4630 cleanup_cfg (CLEANUP_EXPENSIVE);
4640 const pass_data pass_data_rtl_ifcvt =
4642 RTL_PASS, /* type */
4644 OPTGROUP_NONE, /* optinfo_flags */
4645 TV_IFCVT, /* tv_id */
4646 0, /* properties_required */
4647 0, /* properties_provided */
4648 0, /* properties_destroyed */
4649 0, /* todo_flags_start */
4650 TODO_df_finish, /* todo_flags_finish */
4653 class pass_rtl_ifcvt : public rtl_opt_pass
4656 pass_rtl_ifcvt (gcc::context *ctxt)
4657 : rtl_opt_pass (pass_data_rtl_ifcvt, ctxt)
4660 /* opt_pass methods: */
4661 virtual bool gate (function *)
4663 return (optimize > 0) && dbg_cnt (if_conversion);
4666 virtual unsigned int execute (function *)
4668 return rest_of_handle_if_conversion ();
4671 }; // class pass_rtl_ifcvt
4676 make_pass_rtl_ifcvt (gcc::context *ctxt)
4678 return new pass_rtl_ifcvt (ctxt);
4682 /* Rerun if-conversion, as combine may have simplified things enough
4683 to now meet sequence length restrictions. */
4687 const pass_data pass_data_if_after_combine =
4689 RTL_PASS, /* type */
4691 OPTGROUP_NONE, /* optinfo_flags */
4692 TV_IFCVT, /* tv_id */
4693 0, /* properties_required */
4694 0, /* properties_provided */
4695 0, /* properties_destroyed */
4696 0, /* todo_flags_start */
4697 TODO_df_finish, /* todo_flags_finish */
4700 class pass_if_after_combine : public rtl_opt_pass
4703 pass_if_after_combine (gcc::context *ctxt)
4704 : rtl_opt_pass (pass_data_if_after_combine, ctxt)
4707 /* opt_pass methods: */
4708 virtual bool gate (function *)
4710 return optimize > 0 && flag_if_conversion
4711 && dbg_cnt (if_after_combine);
4714 virtual unsigned int execute (function *)
4720 }; // class pass_if_after_combine
4725 make_pass_if_after_combine (gcc::context *ctxt)
4727 return new pass_if_after_combine (ctxt);
4733 const pass_data pass_data_if_after_reload =
4735 RTL_PASS, /* type */
4737 OPTGROUP_NONE, /* optinfo_flags */
4738 TV_IFCVT2, /* tv_id */
4739 0, /* properties_required */
4740 0, /* properties_provided */
4741 0, /* properties_destroyed */
4742 0, /* todo_flags_start */
4743 TODO_df_finish, /* todo_flags_finish */
4746 class pass_if_after_reload : public rtl_opt_pass
4749 pass_if_after_reload (gcc::context *ctxt)
4750 : rtl_opt_pass (pass_data_if_after_reload, ctxt)
4753 /* opt_pass methods: */
4754 virtual bool gate (function *)
4756 return optimize > 0 && flag_if_conversion2
4757 && dbg_cnt (if_after_reload);
4760 virtual unsigned int execute (function *)
4766 }; // class pass_if_after_reload
4771 make_pass_if_after_reload (gcc::context *ctxt)
4773 return new pass_if_after_reload (ctxt);