1 /* If-conversion support.
2 Copyright (C) 2000-2014 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"
29 #include "insn-config.h"
32 #include "hard-reg-set.h"
33 #include "basic-block.h"
37 #include "diagnostic-core.h"
41 #include "tree-pass.h"
44 #include "pointer-set.h"
47 #ifndef HAVE_conditional_move
48 #define HAVE_conditional_move 0
60 #ifndef MAX_CONDITIONAL_EXECUTE
61 #define MAX_CONDITIONAL_EXECUTE \
62 (BRANCH_COST (optimize_function_for_speed_p (cfun), false) \
66 #define IFCVT_MULTIPLE_DUMPS 1
68 #define NULL_BLOCK ((basic_block) NULL)
70 /* True if after combine pass. */
71 static bool ifcvt_after_combine
;
73 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
74 static int num_possible_if_blocks
;
76 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
78 static int num_updated_if_blocks
;
80 /* # of changes made. */
81 static int num_true_changes
;
83 /* Whether conditional execution changes were made. */
84 static int cond_exec_changed_p
;
86 /* Forward references. */
87 static int count_bb_insns (const_basic_block
);
88 static bool cheap_bb_rtx_cost_p (const_basic_block
, int, int);
89 static rtx
first_active_insn (basic_block
);
90 static rtx
last_active_insn (basic_block
, int);
91 static rtx
find_active_insn_before (basic_block
, rtx
);
92 static rtx
find_active_insn_after (basic_block
, rtx
);
93 static basic_block
block_fallthru (basic_block
);
94 static int cond_exec_process_insns (ce_if_block
*, rtx
, rtx
, rtx
, int, int);
95 static rtx
cond_exec_get_condition (rtx
);
96 static rtx
noce_get_condition (rtx
, rtx
*, bool);
97 static int noce_operand_ok (const_rtx
);
98 static void merge_if_block (ce_if_block
*);
99 static int find_cond_trap (basic_block
, edge
, edge
);
100 static basic_block
find_if_header (basic_block
, int);
101 static int block_jumps_and_fallthru_p (basic_block
, basic_block
);
102 static int noce_find_if_block (basic_block
, edge
, edge
, int);
103 static int cond_exec_find_if_block (ce_if_block
*);
104 static int find_if_case_1 (basic_block
, edge
, edge
);
105 static int find_if_case_2 (basic_block
, edge
, edge
);
106 static int dead_or_predicable (basic_block
, basic_block
, basic_block
,
108 static void noce_emit_move_insn (rtx
, rtx
);
109 static rtx
block_has_only_trap (basic_block
);
111 /* Count the number of non-jump active insns in BB. */
114 count_bb_insns (const_basic_block bb
)
117 rtx insn
= BB_HEAD (bb
);
121 if (active_insn_p (insn
) && !JUMP_P (insn
))
124 if (insn
== BB_END (bb
))
126 insn
= NEXT_INSN (insn
);
132 /* Determine whether the total insn_rtx_cost on non-jump insns in
133 basic block BB is less than MAX_COST. This function returns
134 false if the cost of any instruction could not be estimated.
136 The cost of the non-jump insns in BB is scaled by REG_BR_PROB_BASE
137 as those insns are being speculated. MAX_COST is scaled with SCALE
138 plus a small fudge factor. */
141 cheap_bb_rtx_cost_p (const_basic_block bb
, int scale
, int max_cost
)
144 rtx insn
= BB_HEAD (bb
);
145 bool speed
= optimize_bb_for_speed_p (bb
);
147 /* Set scale to REG_BR_PROB_BASE to void the identical scaling
148 applied to insn_rtx_cost when optimizing for size. Only do
149 this after combine because if-conversion might interfere with
150 passes before combine.
152 Use optimize_function_for_speed_p instead of the pre-defined
153 variable speed to make sure it is set to same value for all
154 basic blocks in one if-conversion transformation. */
155 if (!optimize_function_for_speed_p (cfun
) && ifcvt_after_combine
)
156 scale
= REG_BR_PROB_BASE
;
157 /* Our branch probability/scaling factors are just estimates and don't
158 account for cases where we can get speculation for free and other
159 secondary benefits. So we fudge the scale factor to make speculating
160 appear a little more profitable when optimizing for performance. */
162 scale
+= REG_BR_PROB_BASE
/ 8;
169 if (NONJUMP_INSN_P (insn
))
171 int cost
= insn_rtx_cost (PATTERN (insn
), speed
) * REG_BR_PROB_BASE
;
175 /* If this instruction is the load or set of a "stack" register,
176 such as a floating point register on x87, then the cost of
177 speculatively executing this insn may need to include
178 the additional cost of popping its result off of the
179 register stack. Unfortunately, correctly recognizing and
180 accounting for this additional overhead is tricky, so for
181 now we simply prohibit such speculative execution. */
184 rtx set
= single_set (insn
);
185 if (set
&& STACK_REG_P (SET_DEST (set
)))
191 if (count
>= max_cost
)
194 else if (CALL_P (insn
))
197 if (insn
== BB_END (bb
))
199 insn
= NEXT_INSN (insn
);
205 /* Return the first non-jump active insn in the basic block. */
208 first_active_insn (basic_block bb
)
210 rtx insn
= BB_HEAD (bb
);
214 if (insn
== BB_END (bb
))
216 insn
= NEXT_INSN (insn
);
219 while (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
221 if (insn
== BB_END (bb
))
223 insn
= NEXT_INSN (insn
);
232 /* Return the last non-jump active (non-jump) insn in the basic block. */
235 last_active_insn (basic_block bb
, int skip_use_p
)
237 rtx insn
= BB_END (bb
);
238 rtx head
= BB_HEAD (bb
);
242 || DEBUG_INSN_P (insn
)
244 && NONJUMP_INSN_P (insn
)
245 && GET_CODE (PATTERN (insn
)) == USE
))
249 insn
= PREV_INSN (insn
);
258 /* Return the active insn before INSN inside basic block CURR_BB. */
261 find_active_insn_before (basic_block curr_bb
, rtx insn
)
263 if (!insn
|| insn
== BB_HEAD (curr_bb
))
266 while ((insn
= PREV_INSN (insn
)) != NULL_RTX
)
268 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
271 /* No other active insn all the way to the start of the basic block. */
272 if (insn
== BB_HEAD (curr_bb
))
279 /* Return the active insn after INSN inside basic block CURR_BB. */
282 find_active_insn_after (basic_block curr_bb
, rtx insn
)
284 if (!insn
|| insn
== BB_END (curr_bb
))
287 while ((insn
= NEXT_INSN (insn
)) != NULL_RTX
)
289 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
292 /* No other active insn all the way to the end of the basic block. */
293 if (insn
== BB_END (curr_bb
))
300 /* Return the basic block reached by falling though the basic block BB. */
303 block_fallthru (basic_block bb
)
305 edge e
= find_fallthru_edge (bb
->succs
);
307 return (e
) ? e
->dest
: NULL_BLOCK
;
310 /* Go through a bunch of insns, converting them to conditional
311 execution format if possible. Return TRUE if all of the non-note
312 insns were processed. */
315 cond_exec_process_insns (ce_if_block
*ce_info ATTRIBUTE_UNUSED
,
316 /* if block information */rtx start
,
317 /* first insn to look at */rtx end
,
318 /* last insn to look at */rtx test
,
319 /* conditional execution test */int prob_val
,
320 /* probability of branch taken. */int mod_ok
)
322 int must_be_last
= FALSE
;
330 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
332 /* dwarf2out can't cope with conditional prologues. */
333 if (NOTE_P (insn
) && NOTE_KIND (insn
) == NOTE_INSN_PROLOGUE_END
)
336 if (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
339 gcc_assert (NONJUMP_INSN_P (insn
) || CALL_P (insn
));
341 /* dwarf2out can't cope with conditional unwind info. */
342 if (RTX_FRAME_RELATED_P (insn
))
345 /* Remove USE insns that get in the way. */
346 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
348 /* ??? Ug. Actually unlinking the thing is problematic,
349 given what we'd have to coordinate with our callers. */
350 SET_INSN_DELETED (insn
);
354 /* Last insn wasn't last? */
358 if (modified_in_p (test
, insn
))
365 /* Now build the conditional form of the instruction. */
366 pattern
= PATTERN (insn
);
367 xtest
= copy_rtx (test
);
369 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
371 if (GET_CODE (pattern
) == COND_EXEC
)
373 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
376 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
377 COND_EXEC_TEST (pattern
));
378 pattern
= COND_EXEC_CODE (pattern
);
381 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
383 /* If the machine needs to modify the insn being conditionally executed,
384 say for example to force a constant integer operand into a temp
385 register, do so here. */
386 #ifdef IFCVT_MODIFY_INSN
387 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
392 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
394 if (CALL_P (insn
) && prob_val
>= 0)
395 validate_change (insn
, ®_NOTES (insn
),
396 gen_rtx_INT_LIST ((enum machine_mode
) REG_BR_PROB
,
397 prob_val
, REG_NOTES (insn
)), 1);
407 /* Return the condition for a jump. Do not do any special processing. */
410 cond_exec_get_condition (rtx jump
)
414 if (any_condjump_p (jump
))
415 test_if
= SET_SRC (pc_set (jump
));
418 cond
= XEXP (test_if
, 0);
420 /* If this branches to JUMP_LABEL when the condition is false,
421 reverse the condition. */
422 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
423 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
425 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
429 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
436 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
437 to conditional execution. Return TRUE if we were successful at
438 converting the block. */
441 cond_exec_process_if_block (ce_if_block
* ce_info
,
442 /* if block information */int do_multiple_p
)
444 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
445 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
446 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
447 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
448 rtx then_start
; /* first insn in THEN block */
449 rtx then_end
; /* last insn + 1 in THEN block */
450 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
451 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
452 int max
; /* max # of insns to convert. */
453 int then_mod_ok
; /* whether conditional mods are ok in THEN */
454 rtx true_expr
; /* test for else block insns */
455 rtx false_expr
; /* test for then block insns */
456 int true_prob_val
; /* probability of else block */
457 int false_prob_val
; /* probability of then block */
458 rtx then_last_head
= NULL_RTX
; /* Last match at the head of THEN */
459 rtx else_last_head
= NULL_RTX
; /* Last match at the head of ELSE */
460 rtx then_first_tail
= NULL_RTX
; /* First match at the tail of THEN */
461 rtx else_first_tail
= NULL_RTX
; /* First match at the tail of ELSE */
462 int then_n_insns
, else_n_insns
, n_insns
;
463 enum rtx_code false_code
;
466 /* If test is comprised of && or || elements, and we've failed at handling
467 all of them together, just use the last test if it is the special case of
468 && elements without an ELSE block. */
469 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
471 if (else_bb
|| ! ce_info
->and_and_p
)
474 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
475 ce_info
->num_multiple_test_blocks
= 0;
476 ce_info
->num_and_and_blocks
= 0;
477 ce_info
->num_or_or_blocks
= 0;
480 /* Find the conditional jump to the ELSE or JOIN part, and isolate
482 test_expr
= cond_exec_get_condition (BB_END (test_bb
));
486 /* If the conditional jump is more than just a conditional jump,
487 then we can not do conditional execution conversion on this block. */
488 if (! onlyjump_p (BB_END (test_bb
)))
491 /* Collect the bounds of where we're to search, skipping any labels, jumps
492 and notes at the beginning and end of the block. Then count the total
493 number of insns and see if it is small enough to convert. */
494 then_start
= first_active_insn (then_bb
);
495 then_end
= last_active_insn (then_bb
, TRUE
);
496 then_n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
497 n_insns
= then_n_insns
;
498 max
= MAX_CONDITIONAL_EXECUTE
;
505 else_start
= first_active_insn (else_bb
);
506 else_end
= last_active_insn (else_bb
, TRUE
);
507 else_n_insns
= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
508 n_insns
+= else_n_insns
;
510 /* Look for matching sequences at the head and tail of the two blocks,
511 and limit the range of insns to be converted if possible. */
512 n_matching
= flow_find_cross_jump (then_bb
, else_bb
,
513 &then_first_tail
, &else_first_tail
,
515 if (then_first_tail
== BB_HEAD (then_bb
))
516 then_start
= then_end
= NULL_RTX
;
517 if (else_first_tail
== BB_HEAD (else_bb
))
518 else_start
= else_end
= NULL_RTX
;
523 then_end
= find_active_insn_before (then_bb
, then_first_tail
);
525 else_end
= find_active_insn_before (else_bb
, else_first_tail
);
526 n_insns
-= 2 * n_matching
;
531 && then_n_insns
> n_matching
532 && else_n_insns
> n_matching
)
534 int longest_match
= MIN (then_n_insns
- n_matching
,
535 else_n_insns
- n_matching
);
537 = flow_find_head_matching_sequence (then_bb
, else_bb
,
546 /* We won't pass the insns in the head sequence to
547 cond_exec_process_insns, so we need to test them here
548 to make sure that they don't clobber the condition. */
549 for (insn
= BB_HEAD (then_bb
);
550 insn
!= NEXT_INSN (then_last_head
);
551 insn
= NEXT_INSN (insn
))
552 if (!LABEL_P (insn
) && !NOTE_P (insn
)
553 && !DEBUG_INSN_P (insn
)
554 && modified_in_p (test_expr
, insn
))
558 if (then_last_head
== then_end
)
559 then_start
= then_end
= NULL_RTX
;
560 if (else_last_head
== else_end
)
561 else_start
= else_end
= NULL_RTX
;
566 then_start
= find_active_insn_after (then_bb
, then_last_head
);
568 else_start
= find_active_insn_after (else_bb
, else_last_head
);
569 n_insns
-= 2 * n_matching
;
577 /* Map test_expr/test_jump into the appropriate MD tests to use on
578 the conditionally executed code. */
580 true_expr
= test_expr
;
582 false_code
= reversed_comparison_code (true_expr
, BB_END (test_bb
));
583 if (false_code
!= UNKNOWN
)
584 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
585 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
587 false_expr
= NULL_RTX
;
589 #ifdef IFCVT_MODIFY_TESTS
590 /* If the machine description needs to modify the tests, such as setting a
591 conditional execution register from a comparison, it can do so here. */
592 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
594 /* See if the conversion failed. */
595 if (!true_expr
|| !false_expr
)
599 note
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
602 true_prob_val
= XINT (note
, 0);
603 false_prob_val
= REG_BR_PROB_BASE
- true_prob_val
;
611 /* If we have && or || tests, do them here. These tests are in the adjacent
612 blocks after the first block containing the test. */
613 if (ce_info
->num_multiple_test_blocks
> 0)
615 basic_block bb
= test_bb
;
616 basic_block last_test_bb
= ce_info
->last_test_bb
;
625 enum rtx_code f_code
;
627 bb
= block_fallthru (bb
);
628 start
= first_active_insn (bb
);
629 end
= last_active_insn (bb
, TRUE
);
631 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
632 false_prob_val
, FALSE
))
635 /* If the conditional jump is more than just a conditional jump, then
636 we can not do conditional execution conversion on this block. */
637 if (! onlyjump_p (BB_END (bb
)))
640 /* Find the conditional jump and isolate the test. */
641 t
= cond_exec_get_condition (BB_END (bb
));
645 f_code
= reversed_comparison_code (t
, BB_END (bb
));
646 if (f_code
== UNKNOWN
)
649 f
= gen_rtx_fmt_ee (f_code
, GET_MODE (t
), XEXP (t
, 0), XEXP (t
, 1));
650 if (ce_info
->and_and_p
)
652 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
653 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
657 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
658 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
661 /* If the machine description needs to modify the tests, such as
662 setting a conditional execution register from a comparison, it can
664 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
665 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
667 /* See if the conversion failed. */
675 while (bb
!= last_test_bb
);
678 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
679 on then THEN block. */
680 then_mod_ok
= (else_bb
== NULL_BLOCK
);
682 /* Go through the THEN and ELSE blocks converting the insns if possible
683 to conditional execution. */
687 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
688 false_expr
, false_prob_val
,
692 if (else_bb
&& else_end
693 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
694 true_expr
, true_prob_val
, TRUE
))
697 /* If we cannot apply the changes, fail. Do not go through the normal fail
698 processing, since apply_change_group will call cancel_changes. */
699 if (! apply_change_group ())
701 #ifdef IFCVT_MODIFY_CANCEL
702 /* Cancel any machine dependent changes. */
703 IFCVT_MODIFY_CANCEL (ce_info
);
708 #ifdef IFCVT_MODIFY_FINAL
709 /* Do any machine dependent final modifications. */
710 IFCVT_MODIFY_FINAL (ce_info
);
713 /* Conversion succeeded. */
715 fprintf (dump_file
, "%d insn%s converted to conditional execution.\n",
716 n_insns
, (n_insns
== 1) ? " was" : "s were");
718 /* Merge the blocks! If we had matching sequences, make sure to delete one
719 copy at the appropriate location first: delete the copy in the THEN branch
720 for a tail sequence so that the remaining one is executed last for both
721 branches, and delete the copy in the ELSE branch for a head sequence so
722 that the remaining one is executed first for both branches. */
725 rtx from
= then_first_tail
;
727 from
= find_active_insn_after (then_bb
, from
);
728 delete_insn_chain (from
, BB_END (then_bb
), false);
731 delete_insn_chain (first_active_insn (else_bb
), else_last_head
, false);
733 merge_if_block (ce_info
);
734 cond_exec_changed_p
= TRUE
;
738 #ifdef IFCVT_MODIFY_CANCEL
739 /* Cancel any machine dependent changes. */
740 IFCVT_MODIFY_CANCEL (ce_info
);
747 /* Used by noce_process_if_block to communicate with its subroutines.
749 The subroutines know that A and B may be evaluated freely. They
750 know that X is a register. They should insert new instructions
751 before cond_earliest. */
755 /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block. */
756 basic_block test_bb
, then_bb
, else_bb
, join_bb
;
758 /* The jump that ends TEST_BB. */
761 /* The jump condition. */
764 /* New insns should be inserted before this one. */
767 /* Insns in the THEN and ELSE block. There is always just this
768 one insns in those blocks. The insns are single_set insns.
769 If there was no ELSE block, INSN_B is the last insn before
770 COND_EARLIEST, or NULL_RTX. In the former case, the insn
771 operands are still valid, as if INSN_B was moved down below
775 /* The SET_SRC of INSN_A and INSN_B. */
778 /* The SET_DEST of INSN_A. */
781 /* True if this if block is not canonical. In the canonical form of
782 if blocks, the THEN_BB is the block reached via the fallthru edge
783 from TEST_BB. For the noce transformations, we allow the symmetric
785 bool then_else_reversed
;
787 /* Estimated cost of the particular branch instruction. */
791 static rtx
noce_emit_store_flag (struct noce_if_info
*, rtx
, int, int);
792 static int noce_try_move (struct noce_if_info
*);
793 static int noce_try_store_flag (struct noce_if_info
*);
794 static int noce_try_addcc (struct noce_if_info
*);
795 static int noce_try_store_flag_constants (struct noce_if_info
*);
796 static int noce_try_store_flag_mask (struct noce_if_info
*);
797 static rtx
noce_emit_cmove (struct noce_if_info
*, rtx
, enum rtx_code
, rtx
,
799 static int noce_try_cmove (struct noce_if_info
*);
800 static int noce_try_cmove_arith (struct noce_if_info
*);
801 static rtx
noce_get_alt_condition (struct noce_if_info
*, rtx
, rtx
*);
802 static int noce_try_minmax (struct noce_if_info
*);
803 static int noce_try_abs (struct noce_if_info
*);
804 static int noce_try_sign_mask (struct noce_if_info
*);
806 /* Helper function for noce_try_store_flag*. */
809 noce_emit_store_flag (struct noce_if_info
*if_info
, rtx x
, int reversep
,
812 rtx cond
= if_info
->cond
;
816 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
817 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
819 /* If earliest == jump, or when the condition is complex, try to
820 build the store_flag insn directly. */
824 rtx set
= pc_set (if_info
->jump
);
825 cond
= XEXP (SET_SRC (set
), 0);
826 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
827 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
))
828 reversep
= !reversep
;
829 if (if_info
->then_else_reversed
)
830 reversep
= !reversep
;
834 code
= reversed_comparison_code (cond
, if_info
->jump
);
836 code
= GET_CODE (cond
);
838 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
839 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
843 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
845 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
848 tmp
= emit_insn (tmp
);
850 if (recog_memoized (tmp
) >= 0)
856 if_info
->cond_earliest
= if_info
->jump
;
864 /* Don't even try if the comparison operands or the mode of X are weird. */
865 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
868 return emit_store_flag (x
, code
, XEXP (cond
, 0),
869 XEXP (cond
, 1), VOIDmode
,
870 (code
== LTU
|| code
== LEU
871 || code
== GEU
|| code
== GTU
), normalize
);
874 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
875 X is the destination/target and Y is the value to copy. */
878 noce_emit_move_insn (rtx x
, rtx y
)
880 enum machine_mode outmode
;
884 if (GET_CODE (x
) != STRICT_LOW_PART
)
886 rtx seq
, insn
, target
;
890 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
891 otherwise construct a suitable SET pattern ourselves. */
892 insn
= (OBJECT_P (y
) || CONSTANT_P (y
) || GET_CODE (y
) == SUBREG
)
893 ? emit_move_insn (x
, y
)
894 : emit_insn (gen_rtx_SET (VOIDmode
, x
, y
));
898 if (recog_memoized (insn
) <= 0)
900 if (GET_CODE (x
) == ZERO_EXTRACT
)
902 rtx op
= XEXP (x
, 0);
903 unsigned HOST_WIDE_INT size
= INTVAL (XEXP (x
, 1));
904 unsigned HOST_WIDE_INT start
= INTVAL (XEXP (x
, 2));
906 /* store_bit_field expects START to be relative to
907 BYTES_BIG_ENDIAN and adjusts this value for machines with
908 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
909 invoke store_bit_field again it is necessary to have the START
910 value from the first call. */
911 if (BITS_BIG_ENDIAN
!= BYTES_BIG_ENDIAN
)
914 start
= BITS_PER_UNIT
- start
- size
;
917 gcc_assert (REG_P (op
));
918 start
= BITS_PER_WORD
- start
- size
;
922 gcc_assert (start
< (MEM_P (op
) ? BITS_PER_UNIT
: BITS_PER_WORD
));
923 store_bit_field (op
, size
, start
, 0, 0, GET_MODE (x
), y
);
927 switch (GET_RTX_CLASS (GET_CODE (y
)))
930 ot
= code_to_optab (GET_CODE (y
));
934 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
935 if (target
!= NULL_RTX
)
938 emit_move_insn (x
, target
);
947 ot
= code_to_optab (GET_CODE (y
));
951 target
= expand_binop (GET_MODE (y
), ot
,
952 XEXP (y
, 0), XEXP (y
, 1),
954 if (target
!= NULL_RTX
)
957 emit_move_insn (x
, target
);
974 inner
= XEXP (outer
, 0);
975 outmode
= GET_MODE (outer
);
976 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
977 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
,
981 /* Return sequence of instructions generated by if conversion. This
982 function calls end_sequence() to end the current stream, ensures
983 that are instructions are unshared, recognizable non-jump insns.
984 On failure, this function returns a NULL_RTX. */
987 end_ifcvt_sequence (struct noce_if_info
*if_info
)
990 rtx seq
= get_insns ();
992 set_used_flags (if_info
->x
);
993 set_used_flags (if_info
->cond
);
994 set_used_flags (if_info
->a
);
995 set_used_flags (if_info
->b
);
996 unshare_all_rtl_in_chain (seq
);
999 /* Make sure that all of the instructions emitted are recognizable,
1000 and that we haven't introduced a new jump instruction.
1001 As an exercise for the reader, build a general mechanism that
1002 allows proper placement of required clobbers. */
1003 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
1005 || recog_memoized (insn
) == -1)
1011 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
1012 "if (a == b) x = a; else x = b" into "x = b". */
1015 noce_try_move (struct noce_if_info
*if_info
)
1017 rtx cond
= if_info
->cond
;
1018 enum rtx_code code
= GET_CODE (cond
);
1021 if (code
!= NE
&& code
!= EQ
)
1024 /* This optimization isn't valid if either A or B could be a NaN
1025 or a signed zero. */
1026 if (HONOR_NANS (GET_MODE (if_info
->x
))
1027 || HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
1030 /* Check whether the operands of the comparison are A and in
1032 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
1033 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
1034 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
1035 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
1037 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
1039 /* Avoid generating the move if the source is the destination. */
1040 if (! rtx_equal_p (if_info
->x
, y
))
1043 noce_emit_move_insn (if_info
->x
, y
);
1044 seq
= end_ifcvt_sequence (if_info
);
1048 emit_insn_before_setloc (seq
, if_info
->jump
,
1049 INSN_LOCATION (if_info
->insn_a
));
1056 /* Convert "if (test) x = 1; else x = 0".
1058 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
1059 tried in noce_try_store_flag_constants after noce_try_cmove has had
1060 a go at the conversion. */
1063 noce_try_store_flag (struct noce_if_info
*if_info
)
1068 if (CONST_INT_P (if_info
->b
)
1069 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
1070 && if_info
->a
== const0_rtx
)
1072 else if (if_info
->b
== const0_rtx
1073 && CONST_INT_P (if_info
->a
)
1074 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
1075 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1083 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
1086 if (target
!= if_info
->x
)
1087 noce_emit_move_insn (if_info
->x
, target
);
1089 seq
= end_ifcvt_sequence (if_info
);
1093 emit_insn_before_setloc (seq
, if_info
->jump
,
1094 INSN_LOCATION (if_info
->insn_a
));
1104 /* Convert "if (test) x = a; else x = b", for A and B constant. */
1107 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
1111 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
1112 int normalize
, can_reverse
;
1113 enum machine_mode mode
;
1115 if (CONST_INT_P (if_info
->a
)
1116 && CONST_INT_P (if_info
->b
))
1118 mode
= GET_MODE (if_info
->x
);
1119 ifalse
= INTVAL (if_info
->a
);
1120 itrue
= INTVAL (if_info
->b
);
1122 diff
= (unsigned HOST_WIDE_INT
) itrue
- ifalse
;
1123 /* Make sure we can represent the difference between the two values. */
1125 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
1128 diff
= trunc_int_for_mode (diff
, mode
);
1130 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1134 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1136 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
1137 && (STORE_FLAG_VALUE
== 1
1138 || if_info
->branch_cost
>= 2))
1140 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
1141 && (STORE_FLAG_VALUE
== 1 || if_info
->branch_cost
>= 2))
1142 normalize
= 1, reversep
= 1;
1143 else if (itrue
== -1
1144 && (STORE_FLAG_VALUE
== -1
1145 || if_info
->branch_cost
>= 2))
1147 else if (ifalse
== -1 && can_reverse
1148 && (STORE_FLAG_VALUE
== -1 || if_info
->branch_cost
>= 2))
1149 normalize
= -1, reversep
= 1;
1150 else if ((if_info
->branch_cost
>= 2 && STORE_FLAG_VALUE
== -1)
1151 || if_info
->branch_cost
>= 3)
1158 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
1159 diff
= trunc_int_for_mode (-(unsigned HOST_WIDE_INT
) diff
, mode
);
1163 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
1170 /* if (test) x = 3; else x = 4;
1171 => x = 3 + (test == 0); */
1172 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1174 target
= expand_simple_binop (mode
,
1175 (diff
== STORE_FLAG_VALUE
1177 gen_int_mode (ifalse
, mode
), target
,
1178 if_info
->x
, 0, OPTAB_WIDEN
);
1181 /* if (test) x = 8; else x = 0;
1182 => x = (test != 0) << 3; */
1183 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
1185 target
= expand_simple_binop (mode
, ASHIFT
,
1186 target
, GEN_INT (tmp
), if_info
->x
, 0,
1190 /* if (test) x = -1; else x = b;
1191 => x = -(test != 0) | b; */
1192 else if (itrue
== -1)
1194 target
= expand_simple_binop (mode
, IOR
,
1195 target
, gen_int_mode (ifalse
, mode
),
1196 if_info
->x
, 0, OPTAB_WIDEN
);
1199 /* if (test) x = a; else x = b;
1200 => x = (-(test != 0) & (b - a)) + a; */
1203 target
= expand_simple_binop (mode
, AND
,
1204 target
, gen_int_mode (diff
, mode
),
1205 if_info
->x
, 0, OPTAB_WIDEN
);
1207 target
= expand_simple_binop (mode
, PLUS
,
1208 target
, gen_int_mode (ifalse
, mode
),
1209 if_info
->x
, 0, OPTAB_WIDEN
);
1218 if (target
!= if_info
->x
)
1219 noce_emit_move_insn (if_info
->x
, target
);
1221 seq
= end_ifcvt_sequence (if_info
);
1225 emit_insn_before_setloc (seq
, if_info
->jump
,
1226 INSN_LOCATION (if_info
->insn_a
));
1233 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1234 similarly for "foo--". */
1237 noce_try_addcc (struct noce_if_info
*if_info
)
1240 int subtract
, normalize
;
1242 if (GET_CODE (if_info
->a
) == PLUS
1243 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1244 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1247 rtx cond
= if_info
->cond
;
1248 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1250 /* First try to use addcc pattern. */
1251 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1252 && general_operand (XEXP (cond
, 1), VOIDmode
))
1255 target
= emit_conditional_add (if_info
->x
, code
,
1260 XEXP (if_info
->a
, 1),
1261 GET_MODE (if_info
->x
),
1262 (code
== LTU
|| code
== GEU
1263 || code
== LEU
|| code
== GTU
));
1266 if (target
!= if_info
->x
)
1267 noce_emit_move_insn (if_info
->x
, target
);
1269 seq
= end_ifcvt_sequence (if_info
);
1273 emit_insn_before_setloc (seq
, if_info
->jump
,
1274 INSN_LOCATION (if_info
->insn_a
));
1280 /* If that fails, construct conditional increment or decrement using
1282 if (if_info
->branch_cost
>= 2
1283 && (XEXP (if_info
->a
, 1) == const1_rtx
1284 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1287 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1288 subtract
= 0, normalize
= 0;
1289 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1290 subtract
= 1, normalize
= 0;
1292 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1295 target
= noce_emit_store_flag (if_info
,
1296 gen_reg_rtx (GET_MODE (if_info
->x
)),
1300 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1301 subtract
? MINUS
: PLUS
,
1302 if_info
->b
, target
, if_info
->x
,
1306 if (target
!= if_info
->x
)
1307 noce_emit_move_insn (if_info
->x
, target
);
1309 seq
= end_ifcvt_sequence (if_info
);
1313 emit_insn_before_setloc (seq
, if_info
->jump
,
1314 INSN_LOCATION (if_info
->insn_a
));
1324 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1327 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1333 if ((if_info
->branch_cost
>= 2
1334 || STORE_FLAG_VALUE
== -1)
1335 && ((if_info
->a
== const0_rtx
1336 && rtx_equal_p (if_info
->b
, if_info
->x
))
1337 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1340 && if_info
->b
== const0_rtx
1341 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1344 target
= noce_emit_store_flag (if_info
,
1345 gen_reg_rtx (GET_MODE (if_info
->x
)),
1348 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1350 target
, if_info
->x
, 0,
1355 if (target
!= if_info
->x
)
1356 noce_emit_move_insn (if_info
->x
, target
);
1358 seq
= end_ifcvt_sequence (if_info
);
1362 emit_insn_before_setloc (seq
, if_info
->jump
,
1363 INSN_LOCATION (if_info
->insn_a
));
1373 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1376 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1377 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1379 rtx target ATTRIBUTE_UNUSED
;
1380 int unsignedp ATTRIBUTE_UNUSED
;
1382 /* If earliest == jump, try to build the cmove insn directly.
1383 This is helpful when combine has created some complex condition
1384 (like for alpha's cmovlbs) that we can't hope to regenerate
1385 through the normal interface. */
1387 if (if_info
->cond_earliest
== if_info
->jump
)
1391 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1392 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
1393 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
1396 tmp
= emit_insn (tmp
);
1398 if (recog_memoized (tmp
) >= 0)
1410 /* Don't even try if the comparison operands are weird. */
1411 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1412 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1415 #if HAVE_conditional_move
1416 unsignedp
= (code
== LTU
|| code
== GEU
1417 || code
== LEU
|| code
== GTU
);
1419 target
= emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1420 vtrue
, vfalse
, GET_MODE (x
),
1425 /* We might be faced with a situation like:
1428 vtrue = (subreg:M (reg:N VTRUE) BYTE)
1429 vfalse = (subreg:M (reg:N VFALSE) BYTE)
1431 We can't do a conditional move in mode M, but it's possible that we
1432 could do a conditional move in mode N instead and take a subreg of
1435 If we can't create new pseudos, though, don't bother. */
1436 if (reload_completed
)
1439 if (GET_CODE (vtrue
) == SUBREG
&& GET_CODE (vfalse
) == SUBREG
)
1441 rtx reg_vtrue
= SUBREG_REG (vtrue
);
1442 rtx reg_vfalse
= SUBREG_REG (vfalse
);
1443 unsigned int byte_vtrue
= SUBREG_BYTE (vtrue
);
1444 unsigned int byte_vfalse
= SUBREG_BYTE (vfalse
);
1445 rtx promoted_target
;
1447 if (GET_MODE (reg_vtrue
) != GET_MODE (reg_vfalse
)
1448 || byte_vtrue
!= byte_vfalse
1449 || (SUBREG_PROMOTED_VAR_P (vtrue
)
1450 != SUBREG_PROMOTED_VAR_P (vfalse
))
1451 || (SUBREG_PROMOTED_UNSIGNED_P (vtrue
)
1452 != SUBREG_PROMOTED_UNSIGNED_P (vfalse
)))
1455 promoted_target
= gen_reg_rtx (GET_MODE (reg_vtrue
));
1457 target
= emit_conditional_move (promoted_target
, code
, cmp_a
, cmp_b
,
1458 VOIDmode
, reg_vtrue
, reg_vfalse
,
1459 GET_MODE (reg_vtrue
), unsignedp
);
1460 /* Nope, couldn't do it in that mode either. */
1464 target
= gen_rtx_SUBREG (GET_MODE (vtrue
), promoted_target
, byte_vtrue
);
1465 SUBREG_PROMOTED_VAR_P (target
) = SUBREG_PROMOTED_VAR_P (vtrue
);
1466 SUBREG_PROMOTED_UNSIGNED_SET (target
, SUBREG_PROMOTED_UNSIGNED_P (vtrue
));
1467 emit_move_insn (x
, target
);
1473 /* We'll never get here, as noce_process_if_block doesn't call the
1474 functions involved. Ifdef code, however, should be discouraged
1475 because it leads to typos in the code not selected. However,
1476 emit_conditional_move won't exist either. */
1481 /* Try only simple constants and registers here. More complex cases
1482 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1483 has had a go at it. */
1486 noce_try_cmove (struct noce_if_info
*if_info
)
1491 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1492 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1496 code
= GET_CODE (if_info
->cond
);
1497 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1498 XEXP (if_info
->cond
, 0),
1499 XEXP (if_info
->cond
, 1),
1500 if_info
->a
, if_info
->b
);
1504 if (target
!= if_info
->x
)
1505 noce_emit_move_insn (if_info
->x
, target
);
1507 seq
= end_ifcvt_sequence (if_info
);
1511 emit_insn_before_setloc (seq
, if_info
->jump
,
1512 INSN_LOCATION (if_info
->insn_a
));
1525 /* Try more complex cases involving conditional_move. */
1528 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1540 /* A conditional move from two memory sources is equivalent to a
1541 conditional on their addresses followed by a load. Don't do this
1542 early because it'll screw alias analysis. Note that we've
1543 already checked for no side effects. */
1544 /* ??? FIXME: Magic number 5. */
1545 if (cse_not_expected
1546 && MEM_P (a
) && MEM_P (b
)
1547 && MEM_ADDR_SPACE (a
) == MEM_ADDR_SPACE (b
)
1548 && if_info
->branch_cost
>= 5)
1550 enum machine_mode address_mode
= get_address_mode (a
);
1554 x
= gen_reg_rtx (address_mode
);
1558 /* ??? We could handle this if we knew that a load from A or B could
1559 not trap or fault. This is also true if we've already loaded
1560 from the address along the path from ENTRY. */
1561 else if (may_trap_or_fault_p (a
) || may_trap_or_fault_p (b
))
1564 /* if (test) x = a + b; else x = c - d;
1571 code
= GET_CODE (if_info
->cond
);
1572 insn_a
= if_info
->insn_a
;
1573 insn_b
= if_info
->insn_b
;
1575 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1576 if insn_rtx_cost can't be estimated. */
1580 = insn_rtx_cost (PATTERN (insn_a
),
1581 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a
)));
1582 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1591 += insn_rtx_cost (PATTERN (insn_b
),
1592 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b
)));
1593 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1597 /* Possibly rearrange operands to make things come out more natural. */
1598 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1601 if (rtx_equal_p (b
, x
))
1603 else if (general_operand (b
, GET_MODE (b
)))
1608 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1609 tmp
= a
, a
= b
, b
= tmp
;
1610 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1619 /* If either operand is complex, load it into a register first.
1620 The best way to do this is to copy the original insn. In this
1621 way we preserve any clobbers etc that the insn may have had.
1622 This is of course not possible in the IS_MEM case. */
1623 if (! general_operand (a
, GET_MODE (a
)))
1629 tmp
= gen_reg_rtx (GET_MODE (a
));
1630 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1633 goto end_seq_and_fail
;
1636 a
= gen_reg_rtx (GET_MODE (a
));
1637 tmp
= copy_rtx (insn_a
);
1638 set
= single_set (tmp
);
1640 tmp
= emit_insn (PATTERN (tmp
));
1642 if (recog_memoized (tmp
) < 0)
1643 goto end_seq_and_fail
;
1645 if (! general_operand (b
, GET_MODE (b
)))
1651 tmp
= gen_reg_rtx (GET_MODE (b
));
1652 tmp
= gen_rtx_SET (VOIDmode
, tmp
, b
);
1655 goto end_seq_and_fail
;
1658 b
= gen_reg_rtx (GET_MODE (b
));
1659 tmp
= copy_rtx (insn_b
);
1660 set
= single_set (tmp
);
1662 tmp
= PATTERN (tmp
);
1665 /* If insn to set up A clobbers any registers B depends on, try to
1666 swap insn that sets up A with the one that sets up B. If even
1667 that doesn't help, punt. */
1668 last
= get_last_insn ();
1669 if (last
&& modified_in_p (orig_b
, last
))
1671 tmp
= emit_insn_before (tmp
, get_insns ());
1672 if (modified_in_p (orig_a
, tmp
))
1673 goto end_seq_and_fail
;
1676 tmp
= emit_insn (tmp
);
1678 if (recog_memoized (tmp
) < 0)
1679 goto end_seq_and_fail
;
1682 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1683 XEXP (if_info
->cond
, 1), a
, b
);
1686 goto end_seq_and_fail
;
1688 /* If we're handling a memory for above, emit the load now. */
1691 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1693 /* Copy over flags as appropriate. */
1694 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1695 MEM_VOLATILE_P (tmp
) = 1;
1696 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1697 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1699 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1701 gcc_assert (MEM_ADDR_SPACE (if_info
->a
) == MEM_ADDR_SPACE (if_info
->b
));
1702 set_mem_addr_space (tmp
, MEM_ADDR_SPACE (if_info
->a
));
1704 noce_emit_move_insn (if_info
->x
, tmp
);
1706 else if (target
!= x
)
1707 noce_emit_move_insn (x
, target
);
1709 tmp
= end_ifcvt_sequence (if_info
);
1713 emit_insn_before_setloc (tmp
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
1721 /* For most cases, the simplified condition we found is the best
1722 choice, but this is not the case for the min/max/abs transforms.
1723 For these we wish to know that it is A or B in the condition. */
1726 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1729 rtx cond
, set
, insn
;
1732 /* If target is already mentioned in the known condition, return it. */
1733 if (reg_mentioned_p (target
, if_info
->cond
))
1735 *earliest
= if_info
->cond_earliest
;
1736 return if_info
->cond
;
1739 set
= pc_set (if_info
->jump
);
1740 cond
= XEXP (SET_SRC (set
), 0);
1742 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1743 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1744 if (if_info
->then_else_reversed
)
1747 /* If we're looking for a constant, try to make the conditional
1748 have that constant in it. There are two reasons why it may
1749 not have the constant we want:
1751 1. GCC may have needed to put the constant in a register, because
1752 the target can't compare directly against that constant. For
1753 this case, we look for a SET immediately before the comparison
1754 that puts a constant in that register.
1756 2. GCC may have canonicalized the conditional, for example
1757 replacing "if x < 4" with "if x <= 3". We can undo that (or
1758 make equivalent types of changes) to get the constants we need
1759 if they're off by one in the right direction. */
1761 if (CONST_INT_P (target
))
1763 enum rtx_code code
= GET_CODE (if_info
->cond
);
1764 rtx op_a
= XEXP (if_info
->cond
, 0);
1765 rtx op_b
= XEXP (if_info
->cond
, 1);
1768 /* First, look to see if we put a constant in a register. */
1769 prev_insn
= prev_nonnote_insn (if_info
->cond_earliest
);
1771 && BLOCK_FOR_INSN (prev_insn
)
1772 == BLOCK_FOR_INSN (if_info
->cond_earliest
)
1773 && INSN_P (prev_insn
)
1774 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1776 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1778 src
= SET_SRC (PATTERN (prev_insn
));
1779 if (CONST_INT_P (src
))
1781 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1783 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1786 if (CONST_INT_P (op_a
))
1791 code
= swap_condition (code
);
1796 /* Now, look to see if we can get the right constant by
1797 adjusting the conditional. */
1798 if (CONST_INT_P (op_b
))
1800 HOST_WIDE_INT desired_val
= INTVAL (target
);
1801 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1806 if (actual_val
== desired_val
+ 1)
1809 op_b
= GEN_INT (desired_val
);
1813 if (actual_val
== desired_val
- 1)
1816 op_b
= GEN_INT (desired_val
);
1820 if (actual_val
== desired_val
- 1)
1823 op_b
= GEN_INT (desired_val
);
1827 if (actual_val
== desired_val
+ 1)
1830 op_b
= GEN_INT (desired_val
);
1838 /* If we made any changes, generate a new conditional that is
1839 equivalent to what we started with, but has the right
1841 if (code
!= GET_CODE (if_info
->cond
)
1842 || op_a
!= XEXP (if_info
->cond
, 0)
1843 || op_b
!= XEXP (if_info
->cond
, 1))
1845 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1846 *earliest
= if_info
->cond_earliest
;
1851 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1852 earliest
, target
, false, true);
1853 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1856 /* We almost certainly searched back to a different place.
1857 Need to re-verify correct lifetimes. */
1859 /* X may not be mentioned in the range (cond_earliest, jump]. */
1860 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1861 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1864 /* A and B may not be modified in the range [cond_earliest, jump). */
1865 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1867 && (modified_in_p (if_info
->a
, insn
)
1868 || modified_in_p (if_info
->b
, insn
)))
1874 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1877 noce_try_minmax (struct noce_if_info
*if_info
)
1879 rtx cond
, earliest
, target
, seq
;
1880 enum rtx_code code
, op
;
1883 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1884 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1885 to get the target to tell us... */
1886 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1887 || HONOR_NANS (GET_MODE (if_info
->x
)))
1890 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1894 /* Verify the condition is of the form we expect, and canonicalize
1895 the comparison code. */
1896 code
= GET_CODE (cond
);
1897 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1899 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1902 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1904 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1906 code
= swap_condition (code
);
1911 /* Determine what sort of operation this is. Note that the code is for
1912 a taken branch, so the code->operation mapping appears backwards. */
1945 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1946 if_info
->a
, if_info
->b
,
1947 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1953 if (target
!= if_info
->x
)
1954 noce_emit_move_insn (if_info
->x
, target
);
1956 seq
= end_ifcvt_sequence (if_info
);
1960 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
1961 if_info
->cond
= cond
;
1962 if_info
->cond_earliest
= earliest
;
1967 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
1968 "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
1972 noce_try_abs (struct noce_if_info
*if_info
)
1974 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1976 bool one_cmpl
= false;
1978 /* Reject modes with signed zeros. */
1979 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
1982 /* Recognize A and B as constituting an ABS or NABS. The canonical
1983 form is a branch around the negation, taken when the object is the
1984 first operand of a comparison against 0 that evaluates to true. */
1987 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1989 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1991 c
= a
; a
= b
; b
= c
;
1994 else if (GET_CODE (a
) == NOT
&& rtx_equal_p (XEXP (a
, 0), b
))
1999 else if (GET_CODE (b
) == NOT
&& rtx_equal_p (XEXP (b
, 0), a
))
2001 c
= a
; a
= b
; b
= c
;
2008 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
2012 /* Verify the condition is of the form we expect. */
2013 if (rtx_equal_p (XEXP (cond
, 0), b
))
2015 else if (rtx_equal_p (XEXP (cond
, 1), b
))
2023 /* Verify that C is zero. Search one step backward for a
2024 REG_EQUAL note or a simple source if necessary. */
2027 rtx set
, insn
= prev_nonnote_insn (earliest
);
2029 && BLOCK_FOR_INSN (insn
) == BLOCK_FOR_INSN (earliest
)
2030 && (set
= single_set (insn
))
2031 && rtx_equal_p (SET_DEST (set
), c
))
2033 rtx note
= find_reg_equal_equiv_note (insn
);
2043 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
2044 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
2045 c
= get_pool_constant (XEXP (c
, 0));
2047 /* Work around funny ideas get_condition has wrt canonicalization.
2048 Note that these rtx constants are known to be CONST_INT, and
2049 therefore imply integer comparisons. */
2050 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
2052 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
2054 else if (c
!= CONST0_RTX (GET_MODE (b
)))
2057 /* Determine what sort of operation this is. */
2058 switch (GET_CODE (cond
))
2077 target
= expand_one_cmpl_abs_nojump (GET_MODE (if_info
->x
), b
,
2080 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
2082 /* ??? It's a quandary whether cmove would be better here, especially
2083 for integers. Perhaps combine will clean things up. */
2084 if (target
&& negate
)
2087 target
= expand_simple_unop (GET_MODE (target
), NOT
, target
,
2090 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
,
2100 if (target
!= if_info
->x
)
2101 noce_emit_move_insn (if_info
->x
, target
);
2103 seq
= end_ifcvt_sequence (if_info
);
2107 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2108 if_info
->cond
= cond
;
2109 if_info
->cond_earliest
= earliest
;
2114 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
2117 noce_try_sign_mask (struct noce_if_info
*if_info
)
2119 rtx cond
, t
, m
, c
, seq
;
2120 enum machine_mode mode
;
2122 bool t_unconditional
;
2124 cond
= if_info
->cond
;
2125 code
= GET_CODE (cond
);
2130 if (if_info
->a
== const0_rtx
)
2132 if ((code
== LT
&& c
== const0_rtx
)
2133 || (code
== LE
&& c
== constm1_rtx
))
2136 else if (if_info
->b
== const0_rtx
)
2138 if ((code
== GE
&& c
== const0_rtx
)
2139 || (code
== GT
&& c
== constm1_rtx
))
2143 if (! t
|| side_effects_p (t
))
2146 /* We currently don't handle different modes. */
2147 mode
= GET_MODE (t
);
2148 if (GET_MODE (m
) != mode
)
2151 /* This is only profitable if T is unconditionally executed/evaluated in the
2152 original insn sequence or T is cheap. The former happens if B is the
2153 non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
2154 INSN_B which can happen for e.g. conditional stores to memory. For the
2155 cost computation use the block TEST_BB where the evaluation will end up
2156 after the transformation. */
2159 && (if_info
->insn_b
== NULL_RTX
2160 || BLOCK_FOR_INSN (if_info
->insn_b
) == if_info
->test_bb
));
2161 if (!(t_unconditional
2162 || (set_src_cost (t
, optimize_bb_for_speed_p (if_info
->test_bb
))
2163 < COSTS_N_INSNS (2))))
2167 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
2168 "(signed) m >> 31" directly. This benefits targets with specialized
2169 insns to obtain the signmask, but still uses ashr_optab otherwise. */
2170 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
2171 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
2180 noce_emit_move_insn (if_info
->x
, t
);
2182 seq
= end_ifcvt_sequence (if_info
);
2186 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2191 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
2195 noce_try_bitop (struct noce_if_info
*if_info
)
2197 rtx cond
, x
, a
, result
, seq
;
2198 enum machine_mode mode
;
2203 cond
= if_info
->cond
;
2204 code
= GET_CODE (cond
);
2206 /* Check for no else condition. */
2207 if (! rtx_equal_p (x
, if_info
->b
))
2210 /* Check for a suitable condition. */
2211 if (code
!= NE
&& code
!= EQ
)
2213 if (XEXP (cond
, 1) != const0_rtx
)
2215 cond
= XEXP (cond
, 0);
2217 /* ??? We could also handle AND here. */
2218 if (GET_CODE (cond
) == ZERO_EXTRACT
)
2220 if (XEXP (cond
, 1) != const1_rtx
2221 || !CONST_INT_P (XEXP (cond
, 2))
2222 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
2224 bitnum
= INTVAL (XEXP (cond
, 2));
2225 mode
= GET_MODE (x
);
2226 if (BITS_BIG_ENDIAN
)
2227 bitnum
= GET_MODE_BITSIZE (mode
) - 1 - bitnum
;
2228 if (bitnum
< 0 || bitnum
>= HOST_BITS_PER_WIDE_INT
)
2235 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
2237 /* Check for "if (X & C) x = x op C". */
2238 if (! rtx_equal_p (x
, XEXP (a
, 0))
2239 || !CONST_INT_P (XEXP (a
, 1))
2240 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2241 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
2244 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
2245 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
2246 if (GET_CODE (a
) == IOR
)
2247 result
= (code
== NE
) ? a
: NULL_RTX
;
2248 else if (code
== NE
)
2250 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
2251 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
2252 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
2256 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2257 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
2258 result
= simplify_gen_binary (AND
, mode
, x
, result
);
2261 else if (GET_CODE (a
) == AND
)
2263 /* Check for "if (X & C) x &= ~C". */
2264 if (! rtx_equal_p (x
, XEXP (a
, 0))
2265 || !CONST_INT_P (XEXP (a
, 1))
2266 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2267 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
2270 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2271 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2272 result
= (code
== EQ
) ? a
: NULL_RTX
;
2280 noce_emit_move_insn (x
, result
);
2281 seq
= end_ifcvt_sequence (if_info
);
2285 emit_insn_before_setloc (seq
, if_info
->jump
,
2286 INSN_LOCATION (if_info
->insn_a
));
2292 /* Similar to get_condition, only the resulting condition must be
2293 valid at JUMP, instead of at EARLIEST.
2295 If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
2296 THEN block of the caller, and we have to reverse the condition. */
2299 noce_get_condition (rtx jump
, rtx
*earliest
, bool then_else_reversed
)
2304 if (! any_condjump_p (jump
))
2307 set
= pc_set (jump
);
2309 /* If this branches to JUMP_LABEL when the condition is false,
2310 reverse the condition. */
2311 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
2312 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
2314 /* We may have to reverse because the caller's if block is not canonical,
2315 i.e. the THEN block isn't the fallthrough block for the TEST block
2316 (see find_if_header). */
2317 if (then_else_reversed
)
2320 /* If the condition variable is a register and is MODE_INT, accept it. */
2322 cond
= XEXP (SET_SRC (set
), 0);
2323 tmp
= XEXP (cond
, 0);
2324 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
2325 && (GET_MODE (tmp
) != BImode
2326 || !targetm
.small_register_classes_for_mode_p (BImode
)))
2331 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
2332 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2336 /* Otherwise, fall back on canonicalize_condition to do the dirty
2337 work of manipulating MODE_CC values and COMPARE rtx codes. */
2338 tmp
= canonicalize_condition (jump
, cond
, reverse
, earliest
,
2339 NULL_RTX
, false, true);
2341 /* We don't handle side-effects in the condition, like handling
2342 REG_INC notes and making sure no duplicate conditions are emitted. */
2343 if (tmp
!= NULL_RTX
&& side_effects_p (tmp
))
2349 /* Return true if OP is ok for if-then-else processing. */
2352 noce_operand_ok (const_rtx op
)
2354 if (side_effects_p (op
))
2357 /* We special-case memories, so handle any of them with
2358 no address side effects. */
2360 return ! side_effects_p (XEXP (op
, 0));
2362 return ! may_trap_p (op
);
2365 /* Return true if a write into MEM may trap or fault. */
2368 noce_mem_write_may_trap_or_fault_p (const_rtx mem
)
2372 if (MEM_READONLY_P (mem
))
2375 if (may_trap_or_fault_p (mem
))
2378 addr
= XEXP (mem
, 0);
2380 /* Call target hook to avoid the effects of -fpic etc.... */
2381 addr
= targetm
.delegitimize_address (addr
);
2384 switch (GET_CODE (addr
))
2392 addr
= XEXP (addr
, 0);
2396 addr
= XEXP (addr
, 1);
2399 if (CONST_INT_P (XEXP (addr
, 1)))
2400 addr
= XEXP (addr
, 0);
2407 if (SYMBOL_REF_DECL (addr
)
2408 && decl_readonly_section (SYMBOL_REF_DECL (addr
), 0))
2418 /* Return whether we can use store speculation for MEM. TOP_BB is the
2419 basic block above the conditional block where we are considering
2420 doing the speculative store. We look for whether MEM is set
2421 unconditionally later in the function. */
2424 noce_can_store_speculate_p (basic_block top_bb
, const_rtx mem
)
2426 basic_block dominator
;
2428 for (dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, top_bb
);
2430 dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, dominator
))
2434 FOR_BB_INSNS (dominator
, insn
)
2436 /* If we see something that might be a memory barrier, we
2437 have to stop looking. Even if the MEM is set later in
2438 the function, we still don't want to set it
2439 unconditionally before the barrier. */
2441 && (volatile_insn_p (PATTERN (insn
))
2442 || (CALL_P (insn
) && (!RTL_CONST_CALL_P (insn
)))))
2445 if (memory_must_be_modified_in_insn_p (mem
, insn
))
2447 if (modified_in_p (XEXP (mem
, 0), insn
))
2456 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2457 it without using conditional execution. Return TRUE if we were successful
2458 at converting the block. */
2461 noce_process_if_block (struct noce_if_info
*if_info
)
2463 basic_block test_bb
= if_info
->test_bb
; /* test block */
2464 basic_block then_bb
= if_info
->then_bb
; /* THEN */
2465 basic_block else_bb
= if_info
->else_bb
; /* ELSE or NULL */
2466 basic_block join_bb
= if_info
->join_bb
; /* JOIN */
2467 rtx jump
= if_info
->jump
;
2468 rtx cond
= if_info
->cond
;
2471 rtx orig_x
, x
, a
, b
;
2473 /* We're looking for patterns of the form
2475 (1) if (...) x = a; else x = b;
2476 (2) x = b; if (...) x = a;
2477 (3) if (...) x = a; // as if with an initial x = x.
2479 The later patterns require jumps to be more expensive.
2481 ??? For future expansion, look for multiple X in such patterns. */
2483 /* Look for one of the potential sets. */
2484 insn_a
= first_active_insn (then_bb
);
2486 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2487 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2490 x
= SET_DEST (set_a
);
2491 a
= SET_SRC (set_a
);
2493 /* Look for the other potential set. Make sure we've got equivalent
2495 /* ??? This is overconservative. Storing to two different mems is
2496 as easy as conditionally computing the address. Storing to a
2497 single mem merely requires a scratch memory to use as one of the
2498 destination addresses; often the memory immediately below the
2499 stack pointer is available for this. */
2503 insn_b
= first_active_insn (else_bb
);
2505 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2506 || (set_b
= single_set (insn_b
)) == NULL_RTX
2507 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
2512 insn_b
= prev_nonnote_nondebug_insn (if_info
->cond_earliest
);
2513 /* We're going to be moving the evaluation of B down from above
2514 COND_EARLIEST to JUMP. Make sure the relevant data is still
2517 || BLOCK_FOR_INSN (insn_b
) != BLOCK_FOR_INSN (if_info
->cond_earliest
)
2518 || !NONJUMP_INSN_P (insn_b
)
2519 || (set_b
= single_set (insn_b
)) == NULL_RTX
2520 || ! rtx_equal_p (x
, SET_DEST (set_b
))
2521 || ! noce_operand_ok (SET_SRC (set_b
))
2522 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2523 || modified_between_p (SET_SRC (set_b
), insn_b
, jump
)
2524 /* Avoid extending the lifetime of hard registers on small
2525 register class machines. */
2526 || (REG_P (SET_SRC (set_b
))
2527 && HARD_REGISTER_P (SET_SRC (set_b
))
2528 && targetm
.small_register_classes_for_mode_p
2529 (GET_MODE (SET_SRC (set_b
))))
2530 /* Likewise with X. In particular this can happen when
2531 noce_get_condition looks farther back in the instruction
2532 stream than one might expect. */
2533 || reg_overlap_mentioned_p (x
, cond
)
2534 || reg_overlap_mentioned_p (x
, a
)
2535 || modified_between_p (x
, insn_b
, jump
))
2536 insn_b
= set_b
= NULL_RTX
;
2539 /* If x has side effects then only the if-then-else form is safe to
2540 convert. But even in that case we would need to restore any notes
2541 (such as REG_INC) at then end. That can be tricky if
2542 noce_emit_move_insn expands to more than one insn, so disable the
2543 optimization entirely for now if there are side effects. */
2544 if (side_effects_p (x
))
2547 b
= (set_b
? SET_SRC (set_b
) : x
);
2549 /* Only operate on register destinations, and even then avoid extending
2550 the lifetime of hard registers on small register class machines. */
2553 || (HARD_REGISTER_P (x
)
2554 && targetm
.small_register_classes_for_mode_p (GET_MODE (x
))))
2556 if (GET_MODE (x
) == BLKmode
)
2559 if (GET_CODE (x
) == ZERO_EXTRACT
2560 && (!CONST_INT_P (XEXP (x
, 1))
2561 || !CONST_INT_P (XEXP (x
, 2))))
2564 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2565 ? XEXP (x
, 0) : x
));
2568 /* Don't operate on sources that may trap or are volatile. */
2569 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2573 /* Set up the info block for our subroutines. */
2574 if_info
->insn_a
= insn_a
;
2575 if_info
->insn_b
= insn_b
;
2580 /* Try optimizations in some approximation of a useful order. */
2581 /* ??? Should first look to see if X is live incoming at all. If it
2582 isn't, we don't need anything but an unconditional set. */
2584 /* Look and see if A and B are really the same. Avoid creating silly
2585 cmove constructs that no one will fix up later. */
2586 if (rtx_equal_p (a
, b
))
2588 /* If we have an INSN_B, we don't have to create any new rtl. Just
2589 move the instruction that we already have. If we don't have an
2590 INSN_B, that means that A == X, and we've got a noop move. In
2591 that case don't do anything and let the code below delete INSN_A. */
2592 if (insn_b
&& else_bb
)
2596 if (else_bb
&& insn_b
== BB_END (else_bb
))
2597 BB_END (else_bb
) = PREV_INSN (insn_b
);
2598 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2600 /* If there was a REG_EQUAL note, delete it since it may have been
2601 true due to this insn being after a jump. */
2602 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2603 remove_note (insn_b
, note
);
2607 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2608 x must be executed twice. */
2609 else if (insn_b
&& side_effects_p (orig_x
))
2616 if (!set_b
&& MEM_P (orig_x
))
2618 /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
2619 for optimizations if writing to x may trap or fault,
2620 i.e. it's a memory other than a static var or a stack slot,
2621 is misaligned on strict aligned machines or is read-only. If
2622 x is a read-only memory, then the program is valid only if we
2623 avoid the store into it. If there are stores on both the
2624 THEN and ELSE arms, then we can go ahead with the conversion;
2625 either the program is broken, or the condition is always
2626 false such that the other memory is selected. */
2627 if (noce_mem_write_may_trap_or_fault_p (orig_x
))
2630 /* Avoid store speculation: given "if (...) x = a" where x is a
2631 MEM, we only want to do the store if x is always set
2632 somewhere in the function. This avoids cases like
2633 if (pthread_mutex_trylock(mutex))
2635 where we only want global_variable to be changed if the mutex
2636 is held. FIXME: This should ideally be expressed directly in
2638 if (!noce_can_store_speculate_p (test_bb
, orig_x
))
2642 if (noce_try_move (if_info
))
2644 if (noce_try_store_flag (if_info
))
2646 if (noce_try_bitop (if_info
))
2648 if (noce_try_minmax (if_info
))
2650 if (noce_try_abs (if_info
))
2652 if (HAVE_conditional_move
2653 && noce_try_cmove (if_info
))
2655 if (! targetm
.have_conditional_execution ())
2657 if (noce_try_store_flag_constants (if_info
))
2659 if (noce_try_addcc (if_info
))
2661 if (noce_try_store_flag_mask (if_info
))
2663 if (HAVE_conditional_move
2664 && noce_try_cmove_arith (if_info
))
2666 if (noce_try_sign_mask (if_info
))
2670 if (!else_bb
&& set_b
)
2672 insn_b
= set_b
= NULL_RTX
;
2681 /* If we used a temporary, fix it up now. */
2687 noce_emit_move_insn (orig_x
, x
);
2689 set_used_flags (orig_x
);
2690 unshare_all_rtl_in_chain (seq
);
2693 emit_insn_before_setloc (seq
, BB_END (test_bb
), INSN_LOCATION (insn_a
));
2696 /* The original THEN and ELSE blocks may now be removed. The test block
2697 must now jump to the join block. If the test block and the join block
2698 can be merged, do so. */
2701 delete_basic_block (else_bb
);
2705 remove_edge (find_edge (test_bb
, join_bb
));
2707 remove_edge (find_edge (then_bb
, join_bb
));
2708 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2709 delete_basic_block (then_bb
);
2712 if (can_merge_blocks_p (test_bb
, join_bb
))
2714 merge_blocks (test_bb
, join_bb
);
2718 num_updated_if_blocks
++;
2722 /* Check whether a block is suitable for conditional move conversion.
2723 Every insn must be a simple set of a register to a constant or a
2724 register. For each assignment, store the value in the pointer map
2725 VALS, keyed indexed by register pointer, then store the register
2726 pointer in REGS. COND is the condition we will test. */
2729 check_cond_move_block (basic_block bb
,
2730 struct pointer_map_t
*vals
,
2736 /* We can only handle simple jumps at the end of the basic block.
2737 It is almost impossible to update the CFG otherwise. */
2739 if (JUMP_P (insn
) && !onlyjump_p (insn
))
2742 FOR_BB_INSNS (bb
, insn
)
2747 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2749 set
= single_set (insn
);
2753 dest
= SET_DEST (set
);
2754 src
= SET_SRC (set
);
2756 || (HARD_REGISTER_P (dest
)
2757 && targetm
.small_register_classes_for_mode_p (GET_MODE (dest
))))
2760 if (!CONSTANT_P (src
) && !register_operand (src
, VOIDmode
))
2763 if (side_effects_p (src
) || side_effects_p (dest
))
2766 if (may_trap_p (src
) || may_trap_p (dest
))
2769 /* Don't try to handle this if the source register was
2770 modified earlier in the block. */
2772 && pointer_map_contains (vals
, src
))
2773 || (GET_CODE (src
) == SUBREG
&& REG_P (SUBREG_REG (src
))
2774 && pointer_map_contains (vals
, SUBREG_REG (src
))))
2777 /* Don't try to handle this if the destination register was
2778 modified earlier in the block. */
2779 if (pointer_map_contains (vals
, dest
))
2782 /* Don't try to handle this if the condition uses the
2783 destination register. */
2784 if (reg_overlap_mentioned_p (dest
, cond
))
2787 /* Don't try to handle this if the source register is modified
2788 later in the block. */
2789 if (!CONSTANT_P (src
)
2790 && modified_between_p (src
, insn
, NEXT_INSN (BB_END (bb
))))
2793 slot
= pointer_map_insert (vals
, (void *) dest
);
2794 *slot
= (void *) src
;
2796 regs
->safe_push (dest
);
2802 /* Given a basic block BB suitable for conditional move conversion,
2803 a condition COND, and pointer maps THEN_VALS and ELSE_VALS containing
2804 the register values depending on COND, emit the insns in the block as
2805 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2806 processed. The caller has started a sequence for the conversion.
2807 Return true if successful, false if something goes wrong. */
2810 cond_move_convert_if_block (struct noce_if_info
*if_infop
,
2811 basic_block bb
, rtx cond
,
2812 struct pointer_map_t
*then_vals
,
2813 struct pointer_map_t
*else_vals
,
2817 rtx insn
, cond_arg0
, cond_arg1
;
2819 code
= GET_CODE (cond
);
2820 cond_arg0
= XEXP (cond
, 0);
2821 cond_arg1
= XEXP (cond
, 1);
2823 FOR_BB_INSNS (bb
, insn
)
2825 rtx set
, target
, dest
, t
, e
;
2826 void **then_slot
, **else_slot
;
2828 /* ??? Maybe emit conditional debug insn? */
2829 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2831 set
= single_set (insn
);
2832 gcc_assert (set
&& REG_P (SET_DEST (set
)));
2834 dest
= SET_DEST (set
);
2836 then_slot
= pointer_map_contains (then_vals
, dest
);
2837 else_slot
= pointer_map_contains (else_vals
, dest
);
2838 t
= then_slot
? (rtx
) *then_slot
: NULL_RTX
;
2839 e
= else_slot
? (rtx
) *else_slot
: NULL_RTX
;
2843 /* If this register was set in the then block, we already
2844 handled this case there. */
2857 target
= noce_emit_cmove (if_infop
, dest
, code
, cond_arg0
, cond_arg1
,
2863 noce_emit_move_insn (dest
, target
);
2869 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2870 it using only conditional moves. Return TRUE if we were successful at
2871 converting the block. */
2874 cond_move_process_if_block (struct noce_if_info
*if_info
)
2876 basic_block test_bb
= if_info
->test_bb
;
2877 basic_block then_bb
= if_info
->then_bb
;
2878 basic_block else_bb
= if_info
->else_bb
;
2879 basic_block join_bb
= if_info
->join_bb
;
2880 rtx jump
= if_info
->jump
;
2881 rtx cond
= if_info
->cond
;
2885 struct pointer_map_t
*then_vals
;
2886 struct pointer_map_t
*else_vals
;
2887 vec
<rtx
> then_regs
= vNULL
;
2888 vec
<rtx
> else_regs
= vNULL
;
2890 int success_p
= FALSE
;
2892 /* Build a mapping for each block to the value used for each
2894 then_vals
= pointer_map_create ();
2895 else_vals
= pointer_map_create ();
2897 /* Make sure the blocks are suitable. */
2898 if (!check_cond_move_block (then_bb
, then_vals
, &then_regs
, cond
)
2900 && !check_cond_move_block (else_bb
, else_vals
, &else_regs
, cond
)))
2903 /* Make sure the blocks can be used together. If the same register
2904 is set in both blocks, and is not set to a constant in both
2905 cases, then both blocks must set it to the same register. We
2906 have already verified that if it is set to a register, that the
2907 source register does not change after the assignment. Also count
2908 the number of registers set in only one of the blocks. */
2910 FOR_EACH_VEC_ELT (then_regs
, i
, reg
)
2912 void **then_slot
= pointer_map_contains (then_vals
, reg
);
2913 void **else_slot
= pointer_map_contains (else_vals
, reg
);
2915 gcc_checking_assert (then_slot
);
2920 rtx then_val
= (rtx
) *then_slot
;
2921 rtx else_val
= (rtx
) *else_slot
;
2922 if (!CONSTANT_P (then_val
) && !CONSTANT_P (else_val
)
2923 && !rtx_equal_p (then_val
, else_val
))
2928 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
2929 FOR_EACH_VEC_ELT (else_regs
, i
, reg
)
2931 gcc_checking_assert (pointer_map_contains (else_vals
, reg
));
2932 if (!pointer_map_contains (then_vals
, reg
))
2936 /* Make sure it is reasonable to convert this block. What matters
2937 is the number of assignments currently made in only one of the
2938 branches, since if we convert we are going to always execute
2940 if (c
> MAX_CONDITIONAL_EXECUTE
)
2943 /* Try to emit the conditional moves. First do the then block,
2944 then do anything left in the else blocks. */
2946 if (!cond_move_convert_if_block (if_info
, then_bb
, cond
,
2947 then_vals
, else_vals
, false)
2949 && !cond_move_convert_if_block (if_info
, else_bb
, cond
,
2950 then_vals
, else_vals
, true)))
2955 seq
= end_ifcvt_sequence (if_info
);
2959 loc_insn
= first_active_insn (then_bb
);
2962 loc_insn
= first_active_insn (else_bb
);
2963 gcc_assert (loc_insn
);
2965 emit_insn_before_setloc (seq
, jump
, INSN_LOCATION (loc_insn
));
2969 delete_basic_block (else_bb
);
2973 remove_edge (find_edge (test_bb
, join_bb
));
2975 remove_edge (find_edge (then_bb
, join_bb
));
2976 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2977 delete_basic_block (then_bb
);
2980 if (can_merge_blocks_p (test_bb
, join_bb
))
2982 merge_blocks (test_bb
, join_bb
);
2986 num_updated_if_blocks
++;
2991 pointer_map_destroy (then_vals
);
2992 pointer_map_destroy (else_vals
);
2993 then_regs
.release ();
2994 else_regs
.release ();
2999 /* Determine if a given basic block heads a simple IF-THEN-JOIN or an
3000 IF-THEN-ELSE-JOIN block.
3002 If so, we'll try to convert the insns to not require the branch,
3003 using only transformations that do not require conditional execution.
3005 Return TRUE if we were successful at converting the block. */
3008 noce_find_if_block (basic_block test_bb
, edge then_edge
, edge else_edge
,
3011 basic_block then_bb
, else_bb
, join_bb
;
3012 bool then_else_reversed
= false;
3015 struct noce_if_info if_info
;
3017 /* We only ever should get here before reload. */
3018 gcc_assert (!reload_completed
);
3020 /* Recognize an IF-THEN-ELSE-JOIN block. */
3021 if (single_pred_p (then_edge
->dest
)
3022 && single_succ_p (then_edge
->dest
)
3023 && single_pred_p (else_edge
->dest
)
3024 && single_succ_p (else_edge
->dest
)
3025 && single_succ (then_edge
->dest
) == single_succ (else_edge
->dest
))
3027 then_bb
= then_edge
->dest
;
3028 else_bb
= else_edge
->dest
;
3029 join_bb
= single_succ (then_bb
);
3031 /* Recognize an IF-THEN-JOIN block. */
3032 else if (single_pred_p (then_edge
->dest
)
3033 && single_succ_p (then_edge
->dest
)
3034 && single_succ (then_edge
->dest
) == else_edge
->dest
)
3036 then_bb
= then_edge
->dest
;
3037 else_bb
= NULL_BLOCK
;
3038 join_bb
= else_edge
->dest
;
3040 /* Recognize an IF-ELSE-JOIN block. We can have those because the order
3041 of basic blocks in cfglayout mode does not matter, so the fallthrough
3042 edge can go to any basic block (and not just to bb->next_bb, like in
3044 else if (single_pred_p (else_edge
->dest
)
3045 && single_succ_p (else_edge
->dest
)
3046 && single_succ (else_edge
->dest
) == then_edge
->dest
)
3048 /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
3049 To make this work, we have to invert the THEN and ELSE blocks
3050 and reverse the jump condition. */
3051 then_bb
= else_edge
->dest
;
3052 else_bb
= NULL_BLOCK
;
3053 join_bb
= single_succ (then_bb
);
3054 then_else_reversed
= true;
3057 /* Not a form we can handle. */
3060 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3061 if (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3064 && single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3067 num_possible_if_blocks
++;
3072 "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
3073 (else_bb
) ? "-ELSE" : "",
3074 pass
, test_bb
->index
, then_bb
->index
);
3077 fprintf (dump_file
, ", else %d", else_bb
->index
);
3079 fprintf (dump_file
, ", join %d\n", join_bb
->index
);
3082 /* If the conditional jump is more than just a conditional
3083 jump, then we can not do if-conversion on this block. */
3084 jump
= BB_END (test_bb
);
3085 if (! onlyjump_p (jump
))
3088 /* If this is not a standard conditional jump, we can't parse it. */
3089 cond
= noce_get_condition (jump
, &cond_earliest
, then_else_reversed
);
3093 /* We must be comparing objects whose modes imply the size. */
3094 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3097 /* Initialize an IF_INFO struct to pass around. */
3098 memset (&if_info
, 0, sizeof if_info
);
3099 if_info
.test_bb
= test_bb
;
3100 if_info
.then_bb
= then_bb
;
3101 if_info
.else_bb
= else_bb
;
3102 if_info
.join_bb
= join_bb
;
3103 if_info
.cond
= cond
;
3104 if_info
.cond_earliest
= cond_earliest
;
3105 if_info
.jump
= jump
;
3106 if_info
.then_else_reversed
= then_else_reversed
;
3107 if_info
.branch_cost
= BRANCH_COST (optimize_bb_for_speed_p (test_bb
),
3108 predictable_edge_p (then_edge
));
3110 /* Do the real work. */
3112 if (noce_process_if_block (&if_info
))
3115 if (HAVE_conditional_move
3116 && cond_move_process_if_block (&if_info
))
3123 /* Merge the blocks and mark for local life update. */
3126 merge_if_block (struct ce_if_block
* ce_info
)
3128 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
3129 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
3130 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
3131 basic_block join_bb
= ce_info
->join_bb
; /* join block */
3132 basic_block combo_bb
;
3134 /* All block merging is done into the lower block numbers. */
3137 df_set_bb_dirty (test_bb
);
3139 /* Merge any basic blocks to handle && and || subtests. Each of
3140 the blocks are on the fallthru path from the predecessor block. */
3141 if (ce_info
->num_multiple_test_blocks
> 0)
3143 basic_block bb
= test_bb
;
3144 basic_block last_test_bb
= ce_info
->last_test_bb
;
3145 basic_block fallthru
= block_fallthru (bb
);
3150 fallthru
= block_fallthru (bb
);
3151 merge_blocks (combo_bb
, bb
);
3154 while (bb
!= last_test_bb
);
3157 /* Merge TEST block into THEN block. Normally the THEN block won't have a
3158 label, but it might if there were || tests. That label's count should be
3159 zero, and it normally should be removed. */
3163 /* If THEN_BB has no successors, then there's a BARRIER after it.
3164 If COMBO_BB has more than one successor (THEN_BB), then that BARRIER
3165 is no longer needed, and in fact it is incorrect to leave it in
3167 if (EDGE_COUNT (then_bb
->succs
) == 0
3168 && EDGE_COUNT (combo_bb
->succs
) > 1)
3170 rtx end
= NEXT_INSN (BB_END (then_bb
));
3171 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3172 end
= NEXT_INSN (end
);
3174 if (end
&& BARRIER_P (end
))
3177 merge_blocks (combo_bb
, then_bb
);
3181 /* The ELSE block, if it existed, had a label. That label count
3182 will almost always be zero, but odd things can happen when labels
3183 get their addresses taken. */
3186 /* If ELSE_BB has no successors, then there's a BARRIER after it.
3187 If COMBO_BB has more than one successor (ELSE_BB), then that BARRIER
3188 is no longer needed, and in fact it is incorrect to leave it in
3190 if (EDGE_COUNT (else_bb
->succs
) == 0
3191 && EDGE_COUNT (combo_bb
->succs
) > 1)
3193 rtx end
= NEXT_INSN (BB_END (else_bb
));
3194 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3195 end
= NEXT_INSN (end
);
3197 if (end
&& BARRIER_P (end
))
3200 merge_blocks (combo_bb
, else_bb
);
3204 /* If there was no join block reported, that means it was not adjacent
3205 to the others, and so we cannot merge them. */
3209 rtx last
= BB_END (combo_bb
);
3211 /* The outgoing edge for the current COMBO block should already
3212 be correct. Verify this. */
3213 if (EDGE_COUNT (combo_bb
->succs
) == 0)
3214 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
3215 || (NONJUMP_INSN_P (last
)
3216 && GET_CODE (PATTERN (last
)) == TRAP_IF
3217 && (TRAP_CONDITION (PATTERN (last
))
3218 == const_true_rtx
)));
3221 /* There should still be something at the end of the THEN or ELSE
3222 blocks taking us to our final destination. */
3223 gcc_assert (JUMP_P (last
)
3224 || (EDGE_SUCC (combo_bb
, 0)->dest
3225 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3227 && SIBLING_CALL_P (last
))
3228 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
3229 && can_throw_internal (last
)));
3232 /* The JOIN block may have had quite a number of other predecessors too.
3233 Since we've already merged the TEST, THEN and ELSE blocks, we should
3234 have only one remaining edge from our if-then-else diamond. If there
3235 is more than one remaining edge, it must come from elsewhere. There
3236 may be zero incoming edges if the THEN block didn't actually join
3237 back up (as with a call to a non-return function). */
3238 else if (EDGE_COUNT (join_bb
->preds
) < 2
3239 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3241 /* We can merge the JOIN cleanly and update the dataflow try
3242 again on this pass.*/
3243 merge_blocks (combo_bb
, join_bb
);
3248 /* We cannot merge the JOIN. */
3250 /* The outgoing edge for the current COMBO block should already
3251 be correct. Verify this. */
3252 gcc_assert (single_succ_p (combo_bb
)
3253 && single_succ (combo_bb
) == join_bb
);
3255 /* Remove the jump and cruft from the end of the COMBO block. */
3256 if (join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3257 tidy_fallthru_edge (single_succ_edge (combo_bb
));
3260 num_updated_if_blocks
++;
3263 /* Find a block ending in a simple IF condition and try to transform it
3264 in some way. When converting a multi-block condition, put the new code
3265 in the first such block and delete the rest. Return a pointer to this
3266 first block if some transformation was done. Return NULL otherwise. */
3269 find_if_header (basic_block test_bb
, int pass
)
3271 ce_if_block ce_info
;
3275 /* The kind of block we're looking for has exactly two successors. */
3276 if (EDGE_COUNT (test_bb
->succs
) != 2)
3279 then_edge
= EDGE_SUCC (test_bb
, 0);
3280 else_edge
= EDGE_SUCC (test_bb
, 1);
3282 if (df_get_bb_dirty (then_edge
->dest
))
3284 if (df_get_bb_dirty (else_edge
->dest
))
3287 /* Neither edge should be abnormal. */
3288 if ((then_edge
->flags
& EDGE_COMPLEX
)
3289 || (else_edge
->flags
& EDGE_COMPLEX
))
3292 /* Nor exit the loop. */
3293 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
3294 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
3297 /* The THEN edge is canonically the one that falls through. */
3298 if (then_edge
->flags
& EDGE_FALLTHRU
)
3300 else if (else_edge
->flags
& EDGE_FALLTHRU
)
3303 else_edge
= then_edge
;
3307 /* Otherwise this must be a multiway branch of some sort. */
3310 memset (&ce_info
, 0, sizeof (ce_info
));
3311 ce_info
.test_bb
= test_bb
;
3312 ce_info
.then_bb
= then_edge
->dest
;
3313 ce_info
.else_bb
= else_edge
->dest
;
3314 ce_info
.pass
= pass
;
3316 #ifdef IFCVT_MACHDEP_INIT
3317 IFCVT_MACHDEP_INIT (&ce_info
);
3320 if (!reload_completed
3321 && noce_find_if_block (test_bb
, then_edge
, else_edge
, pass
))
3324 if (reload_completed
3325 && targetm
.have_conditional_execution ()
3326 && cond_exec_find_if_block (&ce_info
))
3330 && optab_handler (ctrap_optab
, word_mode
) != CODE_FOR_nothing
3331 && find_cond_trap (test_bb
, then_edge
, else_edge
))
3334 if (dom_info_state (CDI_POST_DOMINATORS
) >= DOM_NO_FAST_QUERY
3335 && (reload_completed
|| !targetm
.have_conditional_execution ()))
3337 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
3339 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
3347 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
3348 /* Set this so we continue looking. */
3349 cond_exec_changed_p
= TRUE
;
3350 return ce_info
.test_bb
;
3353 /* Return true if a block has two edges, one of which falls through to the next
3354 block, and the other jumps to a specific block, so that we can tell if the
3355 block is part of an && test or an || test. Returns either -1 or the number
3356 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
3359 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
3362 int fallthru_p
= FALSE
;
3369 if (!cur_bb
|| !target_bb
)
3372 /* If no edges, obviously it doesn't jump or fallthru. */
3373 if (EDGE_COUNT (cur_bb
->succs
) == 0)
3376 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
3378 if (cur_edge
->flags
& EDGE_COMPLEX
)
3379 /* Anything complex isn't what we want. */
3382 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
3385 else if (cur_edge
->dest
== target_bb
)
3392 if ((jump_p
& fallthru_p
) == 0)
3395 /* Don't allow calls in the block, since this is used to group && and ||
3396 together for conditional execution support. ??? we should support
3397 conditional execution support across calls for IA-64 some day, but
3398 for now it makes the code simpler. */
3399 end
= BB_END (cur_bb
);
3400 insn
= BB_HEAD (cur_bb
);
3402 while (insn
!= NULL_RTX
)
3409 && !DEBUG_INSN_P (insn
)
3410 && GET_CODE (PATTERN (insn
)) != USE
3411 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
3417 insn
= NEXT_INSN (insn
);
3423 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3424 block. If so, we'll try to convert the insns to not require the branch.
3425 Return TRUE if we were successful at converting the block. */
3428 cond_exec_find_if_block (struct ce_if_block
* ce_info
)
3430 basic_block test_bb
= ce_info
->test_bb
;
3431 basic_block then_bb
= ce_info
->then_bb
;
3432 basic_block else_bb
= ce_info
->else_bb
;
3433 basic_block join_bb
= NULL_BLOCK
;
3438 ce_info
->last_test_bb
= test_bb
;
3440 /* We only ever should get here after reload,
3441 and if we have conditional execution. */
3442 gcc_assert (reload_completed
&& targetm
.have_conditional_execution ());
3444 /* Discover if any fall through predecessors of the current test basic block
3445 were && tests (which jump to the else block) or || tests (which jump to
3447 if (single_pred_p (test_bb
)
3448 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
3450 basic_block bb
= single_pred (test_bb
);
3451 basic_block target_bb
;
3452 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
3455 /* Determine if the preceding block is an && or || block. */
3456 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
3458 ce_info
->and_and_p
= TRUE
;
3459 target_bb
= else_bb
;
3461 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
3463 ce_info
->and_and_p
= FALSE
;
3464 target_bb
= then_bb
;
3467 target_bb
= NULL_BLOCK
;
3469 if (target_bb
&& n_insns
<= max_insns
)
3471 int total_insns
= 0;
3474 ce_info
->last_test_bb
= test_bb
;
3476 /* Found at least one && or || block, look for more. */
3479 ce_info
->test_bb
= test_bb
= bb
;
3480 total_insns
+= n_insns
;
3483 if (!single_pred_p (bb
))
3486 bb
= single_pred (bb
);
3487 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
3489 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
3491 ce_info
->num_multiple_test_blocks
= blocks
;
3492 ce_info
->num_multiple_test_insns
= total_insns
;
3494 if (ce_info
->and_and_p
)
3495 ce_info
->num_and_and_blocks
= blocks
;
3497 ce_info
->num_or_or_blocks
= blocks
;
3501 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3502 other than any || blocks which jump to the THEN block. */
3503 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
3506 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3507 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
3509 if (cur_edge
->flags
& EDGE_COMPLEX
)
3513 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
3515 if (cur_edge
->flags
& EDGE_COMPLEX
)
3519 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3520 if (EDGE_COUNT (then_bb
->succs
) > 0
3521 && (!single_succ_p (then_bb
)
3522 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3523 || (epilogue_completed
3524 && tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
3527 /* If the THEN block has no successors, conditional execution can still
3528 make a conditional call. Don't do this unless the ELSE block has
3529 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3530 Check for the last insn of the THEN block being an indirect jump, which
3531 is listed as not having any successors, but confuses the rest of the CE
3532 code processing. ??? we should fix this in the future. */
3533 if (EDGE_COUNT (then_bb
->succs
) == 0)
3535 if (single_pred_p (else_bb
) && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3537 rtx last_insn
= BB_END (then_bb
);
3540 && NOTE_P (last_insn
)
3541 && last_insn
!= BB_HEAD (then_bb
))
3542 last_insn
= PREV_INSN (last_insn
);
3545 && JUMP_P (last_insn
)
3546 && ! simplejump_p (last_insn
))
3550 else_bb
= NULL_BLOCK
;
3556 /* If the THEN block's successor is the other edge out of the TEST block,
3557 then we have an IF-THEN combo without an ELSE. */
3558 else if (single_succ (then_bb
) == else_bb
)
3561 else_bb
= NULL_BLOCK
;
3564 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3565 has exactly one predecessor and one successor, and the outgoing edge
3566 is not complex, then we have an IF-THEN-ELSE combo. */
3567 else if (single_succ_p (else_bb
)
3568 && single_succ (then_bb
) == single_succ (else_bb
)
3569 && single_pred_p (else_bb
)
3570 && !(single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3571 && !(epilogue_completed
3572 && tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
3573 join_bb
= single_succ (else_bb
);
3575 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3579 num_possible_if_blocks
++;
3584 "\nIF-THEN%s block found, pass %d, start block %d "
3585 "[insn %d], then %d [%d]",
3586 (else_bb
) ? "-ELSE" : "",
3589 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
3591 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
3594 fprintf (dump_file
, ", else %d [%d]",
3596 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
3598 fprintf (dump_file
, ", join %d [%d]",
3600 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
3602 if (ce_info
->num_multiple_test_blocks
> 0)
3603 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
3604 ce_info
->num_multiple_test_blocks
,
3605 (ce_info
->and_and_p
) ? "&&" : "||",
3606 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
3607 ce_info
->last_test_bb
->index
,
3608 ((BB_HEAD (ce_info
->last_test_bb
))
3609 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
3612 fputc ('\n', dump_file
);
3615 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3616 first condition for free, since we've already asserted that there's a
3617 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3618 we checked the FALLTHRU flag, those are already adjacent to the last IF
3620 /* ??? As an enhancement, move the ELSE block. Have to deal with
3621 BLOCK notes, if by no other means than backing out the merge if they
3622 exist. Sticky enough I don't want to think about it now. */
3624 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
3626 if ((next
= next
->next_bb
) != join_bb
3627 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3635 /* Do the real work. */
3637 ce_info
->else_bb
= else_bb
;
3638 ce_info
->join_bb
= join_bb
;
3640 /* If we have && and || tests, try to first handle combining the && and ||
3641 tests into the conditional code, and if that fails, go back and handle
3642 it without the && and ||, which at present handles the && case if there
3643 was no ELSE block. */
3644 if (cond_exec_process_if_block (ce_info
, TRUE
))
3647 if (ce_info
->num_multiple_test_blocks
)
3651 if (cond_exec_process_if_block (ce_info
, FALSE
))
3658 /* Convert a branch over a trap, or a branch
3659 to a trap, into a conditional trap. */
3662 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
3664 basic_block then_bb
= then_edge
->dest
;
3665 basic_block else_bb
= else_edge
->dest
;
3666 basic_block other_bb
, trap_bb
;
3667 rtx trap
, jump
, cond
, cond_earliest
, seq
;
3670 /* Locate the block with the trap instruction. */
3671 /* ??? While we look for no successors, we really ought to allow
3672 EH successors. Need to fix merge_if_block for that to work. */
3673 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
3674 trap_bb
= then_bb
, other_bb
= else_bb
;
3675 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
3676 trap_bb
= else_bb
, other_bb
= then_bb
;
3682 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
3683 test_bb
->index
, trap_bb
->index
);
3686 /* If this is not a standard conditional jump, we can't parse it. */
3687 jump
= BB_END (test_bb
);
3688 cond
= noce_get_condition (jump
, &cond_earliest
, false);
3692 /* If the conditional jump is more than just a conditional jump, then
3693 we can not do if-conversion on this block. */
3694 if (! onlyjump_p (jump
))
3697 /* We must be comparing objects whose modes imply the size. */
3698 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3701 /* Reverse the comparison code, if necessary. */
3702 code
= GET_CODE (cond
);
3703 if (then_bb
== trap_bb
)
3705 code
= reversed_comparison_code (cond
, jump
);
3706 if (code
== UNKNOWN
)
3710 /* Attempt to generate the conditional trap. */
3711 seq
= gen_cond_trap (code
, copy_rtx (XEXP (cond
, 0)),
3712 copy_rtx (XEXP (cond
, 1)),
3713 TRAP_CODE (PATTERN (trap
)));
3717 /* Emit the new insns before cond_earliest. */
3718 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATION (trap
));
3720 /* Delete the trap block if possible. */
3721 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
3722 df_set_bb_dirty (test_bb
);
3723 df_set_bb_dirty (then_bb
);
3724 df_set_bb_dirty (else_bb
);
3726 if (EDGE_COUNT (trap_bb
->preds
) == 0)
3728 delete_basic_block (trap_bb
);
3732 /* Wire together the blocks again. */
3733 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
3734 single_succ_edge (test_bb
)->flags
|= EDGE_FALLTHRU
;
3735 else if (trap_bb
== then_bb
)
3739 lab
= JUMP_LABEL (jump
);
3740 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
3741 LABEL_NUSES (lab
) += 1;
3742 JUMP_LABEL (newjump
) = lab
;
3743 emit_barrier_after (newjump
);
3747 if (can_merge_blocks_p (test_bb
, other_bb
))
3749 merge_blocks (test_bb
, other_bb
);
3753 num_updated_if_blocks
++;
3757 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3761 block_has_only_trap (basic_block bb
)
3765 /* We're not the exit block. */
3766 if (bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3769 /* The block must have no successors. */
3770 if (EDGE_COUNT (bb
->succs
) > 0)
3773 /* The only instruction in the THEN block must be the trap. */
3774 trap
= first_active_insn (bb
);
3775 if (! (trap
== BB_END (bb
)
3776 && GET_CODE (PATTERN (trap
)) == TRAP_IF
3777 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
3783 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3784 transformable, but not necessarily the other. There need be no
3787 Return TRUE if we were successful at converting the block.
3789 Cases we'd like to look at:
3792 if (test) goto over; // x not live
3800 if (! test) goto label;
3803 if (test) goto E; // x not live
3817 (3) // This one's really only interesting for targets that can do
3818 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3819 // it results in multiple branches on a cache line, which often
3820 // does not sit well with predictors.
3822 if (test1) goto E; // predicted not taken
3838 (A) Don't do (2) if the branch is predicted against the block we're
3839 eliminating. Do it anyway if we can eliminate a branch; this requires
3840 that the sole successor of the eliminated block postdominate the other
3843 (B) With CE, on (3) we can steal from both sides of the if, creating
3852 Again, this is most useful if J postdominates.
3854 (C) CE substitutes for helpful life information.
3856 (D) These heuristics need a lot of work. */
3858 /* Tests for case 1 above. */
3861 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3863 basic_block then_bb
= then_edge
->dest
;
3864 basic_block else_bb
= else_edge
->dest
;
3866 int then_bb_index
, then_prob
;
3867 rtx else_target
= NULL_RTX
;
3869 /* If we are partitioning hot/cold basic blocks, we don't want to
3870 mess up unconditional or indirect jumps that cross between hot
3873 Basic block partitioning may result in some jumps that appear to
3874 be optimizable (or blocks that appear to be mergeable), but which really
3875 must be left untouched (they are required to make it safely across
3876 partition boundaries). See the comments at the top of
3877 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3879 if ((BB_END (then_bb
)
3880 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3881 || (BB_END (test_bb
)
3882 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3883 || (BB_END (else_bb
)
3884 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3888 /* THEN has one successor. */
3889 if (!single_succ_p (then_bb
))
3892 /* THEN does not fall through, but is not strange either. */
3893 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
3896 /* THEN has one predecessor. */
3897 if (!single_pred_p (then_bb
))
3900 /* THEN must do something. */
3901 if (forwarder_block_p (then_bb
))
3904 num_possible_if_blocks
++;
3907 "\nIF-CASE-1 found, start %d, then %d\n",
3908 test_bb
->index
, then_bb
->index
);
3910 if (then_edge
->probability
)
3911 then_prob
= REG_BR_PROB_BASE
- then_edge
->probability
;
3913 then_prob
= REG_BR_PROB_BASE
/ 2;
3915 /* We're speculating from the THEN path, we want to make sure the cost
3916 of speculation is within reason. */
3917 if (! cheap_bb_rtx_cost_p (then_bb
, then_prob
,
3918 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge
->src
),
3919 predictable_edge_p (then_edge
)))))
3922 if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3924 rtx jump
= BB_END (else_edge
->src
);
3925 gcc_assert (JUMP_P (jump
));
3926 else_target
= JUMP_LABEL (jump
);
3929 /* Registers set are dead, or are predicable. */
3930 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
3931 single_succ_edge (then_bb
), 1))
3934 /* Conversion went ok, including moving the insns and fixing up the
3935 jump. Adjust the CFG to match. */
3937 /* We can avoid creating a new basic block if then_bb is immediately
3938 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3939 through to else_bb. */
3941 if (then_bb
->next_bb
== else_bb
3942 && then_bb
->prev_bb
== test_bb
3943 && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3945 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
3948 else if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3949 new_bb
= force_nonfallthru_and_redirect (FALLTHRU_EDGE (test_bb
),
3950 else_bb
, else_target
);
3952 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
3955 df_set_bb_dirty (test_bb
);
3956 df_set_bb_dirty (else_bb
);
3958 then_bb_index
= then_bb
->index
;
3959 delete_basic_block (then_bb
);
3961 /* Make rest of code believe that the newly created block is the THEN_BB
3962 block we removed. */
3965 df_bb_replace (then_bb_index
, new_bb
);
3966 /* This should have been done above via force_nonfallthru_and_redirect
3967 (possibly called from redirect_edge_and_branch_force). */
3968 gcc_checking_assert (BB_PARTITION (new_bb
) == BB_PARTITION (test_bb
));
3972 num_updated_if_blocks
++;
3977 /* Test for case 2 above. */
3980 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3982 basic_block then_bb
= then_edge
->dest
;
3983 basic_block else_bb
= else_edge
->dest
;
3985 int then_prob
, else_prob
;
3987 /* We do not want to speculate (empty) loop latches. */
3989 && else_bb
->loop_father
->latch
== else_bb
)
3992 /* If we are partitioning hot/cold basic blocks, we don't want to
3993 mess up unconditional or indirect jumps that cross between hot
3996 Basic block partitioning may result in some jumps that appear to
3997 be optimizable (or blocks that appear to be mergeable), but which really
3998 must be left untouched (they are required to make it safely across
3999 partition boundaries). See the comments at the top of
4000 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4002 if ((BB_END (then_bb
)
4003 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
4004 || (BB_END (test_bb
)
4005 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
4006 || (BB_END (else_bb
)
4007 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
4011 /* ELSE has one successor. */
4012 if (!single_succ_p (else_bb
))
4015 else_succ
= single_succ_edge (else_bb
);
4017 /* ELSE outgoing edge is not complex. */
4018 if (else_succ
->flags
& EDGE_COMPLEX
)
4021 /* ELSE has one predecessor. */
4022 if (!single_pred_p (else_bb
))
4025 /* THEN is not EXIT. */
4026 if (then_bb
->index
< NUM_FIXED_BLOCKS
)
4029 if (else_edge
->probability
)
4031 else_prob
= else_edge
->probability
;
4032 then_prob
= REG_BR_PROB_BASE
- else_prob
;
4036 else_prob
= REG_BR_PROB_BASE
/ 2;
4037 then_prob
= REG_BR_PROB_BASE
/ 2;
4040 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
4041 if (else_prob
> then_prob
)
4043 else if (else_succ
->dest
->index
< NUM_FIXED_BLOCKS
4044 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
4050 num_possible_if_blocks
++;
4053 "\nIF-CASE-2 found, start %d, else %d\n",
4054 test_bb
->index
, else_bb
->index
);
4056 /* We're speculating from the ELSE path, we want to make sure the cost
4057 of speculation is within reason. */
4058 if (! cheap_bb_rtx_cost_p (else_bb
, else_prob
,
4059 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge
->src
),
4060 predictable_edge_p (else_edge
)))))
4063 /* Registers set are dead, or are predicable. */
4064 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
, 0))
4067 /* Conversion went ok, including moving the insns and fixing up the
4068 jump. Adjust the CFG to match. */
4070 df_set_bb_dirty (test_bb
);
4071 df_set_bb_dirty (then_bb
);
4072 delete_basic_block (else_bb
);
4075 num_updated_if_blocks
++;
4077 /* ??? We may now fallthru from one of THEN's successors into a join
4078 block. Rerun cleanup_cfg? Examine things manually? Wait? */
4083 /* Used by the code above to perform the actual rtl transformations.
4084 Return TRUE if successful.
4086 TEST_BB is the block containing the conditional branch. MERGE_BB
4087 is the block containing the code to manipulate. DEST_EDGE is an
4088 edge representing a jump to the join block; after the conversion,
4089 TEST_BB should be branching to its destination.
4090 REVERSEP is true if the sense of the branch should be reversed. */
4093 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
4094 basic_block other_bb
, edge dest_edge
, int reversep
)
4096 basic_block new_dest
= dest_edge
->dest
;
4097 rtx head
, end
, jump
, earliest
= NULL_RTX
, old_dest
;
4098 bitmap merge_set
= NULL
;
4099 /* Number of pending changes. */
4100 int n_validated_changes
= 0;
4101 rtx new_dest_label
= NULL_RTX
;
4103 jump
= BB_END (test_bb
);
4105 /* Find the extent of the real code in the merge block. */
4106 head
= BB_HEAD (merge_bb
);
4107 end
= BB_END (merge_bb
);
4109 while (DEBUG_INSN_P (end
) && end
!= head
)
4110 end
= PREV_INSN (end
);
4112 /* If merge_bb ends with a tablejump, predicating/moving insn's
4113 into test_bb and then deleting merge_bb will result in the jumptable
4114 that follows merge_bb being removed along with merge_bb and then we
4115 get an unresolved reference to the jumptable. */
4116 if (tablejump_p (end
, NULL
, NULL
))
4120 head
= NEXT_INSN (head
);
4121 while (DEBUG_INSN_P (head
) && head
!= end
)
4122 head
= NEXT_INSN (head
);
4127 head
= end
= NULL_RTX
;
4130 head
= NEXT_INSN (head
);
4131 while (DEBUG_INSN_P (head
) && head
!= end
)
4132 head
= NEXT_INSN (head
);
4139 head
= end
= NULL_RTX
;
4142 end
= PREV_INSN (end
);
4143 while (DEBUG_INSN_P (end
) && end
!= head
)
4144 end
= PREV_INSN (end
);
4147 /* Don't move frame-related insn across the conditional branch. This
4148 can lead to one of the paths of the branch having wrong unwind info. */
4149 if (epilogue_completed
)
4154 if (INSN_P (insn
) && RTX_FRAME_RELATED_P (insn
))
4158 insn
= NEXT_INSN (insn
);
4162 /* Disable handling dead code by conditional execution if the machine needs
4163 to do anything funny with the tests, etc. */
4164 #ifndef IFCVT_MODIFY_TESTS
4165 if (targetm
.have_conditional_execution ())
4167 /* In the conditional execution case, we have things easy. We know
4168 the condition is reversible. We don't have to check life info
4169 because we're going to conditionally execute the code anyway.
4170 All that's left is making sure the insns involved can actually
4175 cond
= cond_exec_get_condition (jump
);
4179 rtx note
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
4180 int prob_val
= (note
? XINT (note
, 0) : -1);
4184 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
4187 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
4190 prob_val
= REG_BR_PROB_BASE
- prob_val
;
4193 if (cond_exec_process_insns (NULL
, head
, end
, cond
, prob_val
, 0)
4194 && verify_changes (0))
4195 n_validated_changes
= num_validated_changes ();
4203 /* If we allocated new pseudos (e.g. in the conditional move
4204 expander called from noce_emit_cmove), we must resize the
4206 if (max_regno
< max_reg_num ())
4207 max_regno
= max_reg_num ();
4209 /* Try the NCE path if the CE path did not result in any changes. */
4210 if (n_validated_changes
== 0)
4216 /* In the non-conditional execution case, we have to verify that there
4217 are no trapping operations, no calls, no references to memory, and
4218 that any registers modified are dead at the branch site. */
4220 if (!any_condjump_p (jump
))
4223 /* Find the extent of the conditional. */
4224 cond
= noce_get_condition (jump
, &earliest
, false);
4228 live
= BITMAP_ALLOC (®_obstack
);
4229 simulate_backwards_to_point (merge_bb
, live
, end
);
4230 success
= can_move_insns_across (head
, end
, earliest
, jump
,
4232 df_get_live_in (other_bb
), NULL
);
4237 /* Collect the set of registers set in MERGE_BB. */
4238 merge_set
= BITMAP_ALLOC (®_obstack
);
4240 FOR_BB_INSNS (merge_bb
, insn
)
4241 if (NONDEBUG_INSN_P (insn
))
4242 df_simulate_find_defs (insn
, merge_set
);
4244 #ifdef HAVE_simple_return
4245 /* If shrink-wrapping, disable this optimization when test_bb is
4246 the first basic block and merge_bb exits. The idea is to not
4247 move code setting up a return register as that may clobber a
4248 register used to pass function parameters, which then must be
4249 saved in caller-saved regs. A caller-saved reg requires the
4250 prologue, killing a shrink-wrap opportunity. */
4251 if ((flag_shrink_wrap
&& HAVE_simple_return
&& !epilogue_completed
)
4252 && ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
== test_bb
4253 && single_succ_p (new_dest
)
4254 && single_succ (new_dest
) == EXIT_BLOCK_PTR_FOR_FN (cfun
)
4255 && bitmap_intersect_p (df_get_live_in (new_dest
), merge_set
))
4260 return_regs
= BITMAP_ALLOC (®_obstack
);
4262 /* Start off with the intersection of regs used to pass
4263 params and regs used to return values. */
4264 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
4265 if (FUNCTION_ARG_REGNO_P (i
)
4266 && targetm
.calls
.function_value_regno_p (i
))
4267 bitmap_set_bit (return_regs
, INCOMING_REGNO (i
));
4269 bitmap_and_into (return_regs
,
4270 df_get_live_out (ENTRY_BLOCK_PTR_FOR_FN (cfun
)));
4271 bitmap_and_into (return_regs
,
4272 df_get_live_in (EXIT_BLOCK_PTR_FOR_FN (cfun
)));
4273 if (!bitmap_empty_p (return_regs
))
4275 FOR_BB_INSNS_REVERSE (new_dest
, insn
)
4276 if (NONDEBUG_INSN_P (insn
))
4279 unsigned int uid
= INSN_UID (insn
);
4281 /* If this insn sets any reg in return_regs.. */
4282 for (def_rec
= DF_INSN_UID_DEFS (uid
); *def_rec
; def_rec
++)
4284 df_ref def
= *def_rec
;
4285 unsigned r
= DF_REF_REGNO (def
);
4287 if (bitmap_bit_p (return_regs
, r
))
4290 /* ..then add all reg uses to the set of regs
4291 we're interested in. */
4293 df_simulate_uses (insn
, return_regs
);
4295 if (bitmap_intersect_p (merge_set
, return_regs
))
4297 BITMAP_FREE (return_regs
);
4298 BITMAP_FREE (merge_set
);
4302 BITMAP_FREE (return_regs
);
4308 /* We don't want to use normal invert_jump or redirect_jump because
4309 we don't want to delete_insn called. Also, we want to do our own
4310 change group management. */
4312 old_dest
= JUMP_LABEL (jump
);
4313 if (other_bb
!= new_dest
)
4315 if (JUMP_P (BB_END (dest_edge
->src
)))
4316 new_dest_label
= JUMP_LABEL (BB_END (dest_edge
->src
));
4317 else if (new_dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4318 new_dest_label
= ret_rtx
;
4320 new_dest_label
= block_label (new_dest
);
4323 ? ! invert_jump_1 (jump
, new_dest_label
)
4324 : ! redirect_jump_1 (jump
, new_dest_label
))
4328 if (verify_changes (n_validated_changes
))
4329 confirm_change_group ();
4333 if (other_bb
!= new_dest
)
4335 redirect_jump_2 (jump
, old_dest
, new_dest_label
, 0, reversep
);
4337 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
4340 gcov_type count
, probability
;
4341 count
= BRANCH_EDGE (test_bb
)->count
;
4342 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
4343 FALLTHRU_EDGE (test_bb
)->count
= count
;
4344 probability
= BRANCH_EDGE (test_bb
)->probability
;
4345 BRANCH_EDGE (test_bb
)->probability
4346 = FALLTHRU_EDGE (test_bb
)->probability
;
4347 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
4348 update_br_prob_note (test_bb
);
4352 /* Move the insns out of MERGE_BB to before the branch. */
4357 if (end
== BB_END (merge_bb
))
4358 BB_END (merge_bb
) = PREV_INSN (head
);
4360 /* PR 21767: when moving insns above a conditional branch, the REG_EQUAL
4361 notes being moved might become invalid. */
4367 if (! INSN_P (insn
))
4369 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
4372 set
= single_set (insn
);
4373 if (!set
|| !function_invariant_p (SET_SRC (set
))
4374 || !function_invariant_p (XEXP (note
, 0)))
4375 remove_note (insn
, note
);
4376 } while (insn
!= end
&& (insn
= NEXT_INSN (insn
)));
4378 /* PR46315: when moving insns above a conditional branch, the REG_EQUAL
4379 notes referring to the registers being set might become invalid. */
4385 EXECUTE_IF_SET_IN_BITMAP (merge_set
, 0, i
, bi
)
4386 remove_reg_equal_equiv_notes_for_regno (i
);
4388 BITMAP_FREE (merge_set
);
4391 reorder_insns (head
, end
, PREV_INSN (earliest
));
4394 /* Remove the jump and edge if we can. */
4395 if (other_bb
== new_dest
)
4398 remove_edge (BRANCH_EDGE (test_bb
));
4399 /* ??? Can't merge blocks here, as then_bb is still in use.
4400 At minimum, the merge will get done just before bb-reorder. */
4409 BITMAP_FREE (merge_set
);
4414 /* Main entry point for all if-conversion. AFTER_COMBINE is true if
4415 we are after combine pass. */
4418 if_convert (bool after_combine
)
4425 df_live_add_problem ();
4426 df_live_set_all_dirty ();
4429 /* Record whether we are after combine pass. */
4430 ifcvt_after_combine
= after_combine
;
4431 num_possible_if_blocks
= 0;
4432 num_updated_if_blocks
= 0;
4433 num_true_changes
= 0;
4435 loop_optimizer_init (AVOID_CFG_MODIFICATIONS
);
4436 mark_loop_exit_edges ();
4437 loop_optimizer_finalize ();
4438 free_dominance_info (CDI_DOMINATORS
);
4440 /* Compute postdominators. */
4441 calculate_dominance_info (CDI_POST_DOMINATORS
);
4443 df_set_flags (DF_LR_RUN_DCE
);
4445 /* Go through each of the basic blocks looking for things to convert. If we
4446 have conditional execution, we make multiple passes to allow us to handle
4447 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
4452 /* Only need to do dce on the first pass. */
4453 df_clear_flags (DF_LR_RUN_DCE
);
4454 cond_exec_changed_p
= FALSE
;
4457 #ifdef IFCVT_MULTIPLE_DUMPS
4458 if (dump_file
&& pass
> 1)
4459 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
4462 FOR_EACH_BB_FN (bb
, cfun
)
4465 while (!df_get_bb_dirty (bb
)
4466 && (new_bb
= find_if_header (bb
, pass
)) != NULL
)
4470 #ifdef IFCVT_MULTIPLE_DUMPS
4471 if (dump_file
&& cond_exec_changed_p
)
4472 print_rtl_with_bb (dump_file
, get_insns (), dump_flags
);
4475 while (cond_exec_changed_p
);
4477 #ifdef IFCVT_MULTIPLE_DUMPS
4479 fprintf (dump_file
, "\n\n========== no more changes\n");
4482 free_dominance_info (CDI_POST_DOMINATORS
);
4487 clear_aux_for_blocks ();
4489 /* If we allocated new pseudos, we must resize the array for sched1. */
4490 if (max_regno
< max_reg_num ())
4491 max_regno
= max_reg_num ();
4493 /* Write the final stats. */
4494 if (dump_file
&& num_possible_if_blocks
> 0)
4497 "\n%d possible IF blocks searched.\n",
4498 num_possible_if_blocks
);
4500 "%d IF blocks converted.\n",
4501 num_updated_if_blocks
);
4503 "%d true changes made.\n\n\n",
4508 df_remove_problem (df_live
);
4510 #ifdef ENABLE_CHECKING
4511 verify_flow_info ();
4515 /* If-conversion and CFG cleanup. */
4517 rest_of_handle_if_conversion (void)
4519 if (flag_if_conversion
)
4523 dump_reg_info (dump_file
);
4524 dump_flow_info (dump_file
, dump_flags
);
4526 cleanup_cfg (CLEANUP_EXPENSIVE
);
4536 const pass_data pass_data_rtl_ifcvt
=
4538 RTL_PASS
, /* type */
4540 OPTGROUP_NONE
, /* optinfo_flags */
4541 true, /* has_execute */
4542 TV_IFCVT
, /* tv_id */
4543 0, /* properties_required */
4544 0, /* properties_provided */
4545 0, /* properties_destroyed */
4546 0, /* todo_flags_start */
4547 TODO_df_finish
, /* todo_flags_finish */
4550 class pass_rtl_ifcvt
: public rtl_opt_pass
4553 pass_rtl_ifcvt (gcc::context
*ctxt
)
4554 : rtl_opt_pass (pass_data_rtl_ifcvt
, ctxt
)
4557 /* opt_pass methods: */
4558 virtual bool gate (function
*)
4560 return (optimize
> 0) && dbg_cnt (if_conversion
);
4563 virtual unsigned int execute (function
*)
4565 return rest_of_handle_if_conversion ();
4568 }; // class pass_rtl_ifcvt
4573 make_pass_rtl_ifcvt (gcc::context
*ctxt
)
4575 return new pass_rtl_ifcvt (ctxt
);
4579 /* Rerun if-conversion, as combine may have simplified things enough
4580 to now meet sequence length restrictions. */
4584 const pass_data pass_data_if_after_combine
=
4586 RTL_PASS
, /* type */
4588 OPTGROUP_NONE
, /* optinfo_flags */
4589 true, /* has_execute */
4590 TV_IFCVT
, /* tv_id */
4591 0, /* properties_required */
4592 0, /* properties_provided */
4593 0, /* properties_destroyed */
4594 0, /* todo_flags_start */
4595 TODO_df_finish
, /* todo_flags_finish */
4598 class pass_if_after_combine
: public rtl_opt_pass
4601 pass_if_after_combine (gcc::context
*ctxt
)
4602 : rtl_opt_pass (pass_data_if_after_combine
, ctxt
)
4605 /* opt_pass methods: */
4606 virtual bool gate (function
*)
4608 return optimize
> 0 && flag_if_conversion
4609 && dbg_cnt (if_after_combine
);
4612 virtual unsigned int execute (function
*)
4618 }; // class pass_if_after_combine
4623 make_pass_if_after_combine (gcc::context
*ctxt
)
4625 return new pass_if_after_combine (ctxt
);
4631 const pass_data pass_data_if_after_reload
=
4633 RTL_PASS
, /* type */
4635 OPTGROUP_NONE
, /* optinfo_flags */
4636 true, /* has_execute */
4637 TV_IFCVT2
, /* tv_id */
4638 0, /* properties_required */
4639 0, /* properties_provided */
4640 0, /* properties_destroyed */
4641 0, /* todo_flags_start */
4642 TODO_df_finish
, /* todo_flags_finish */
4645 class pass_if_after_reload
: public rtl_opt_pass
4648 pass_if_after_reload (gcc::context
*ctxt
)
4649 : rtl_opt_pass (pass_data_if_after_reload
, ctxt
)
4652 /* opt_pass methods: */
4653 virtual bool gate (function
*)
4655 return optimize
> 0 && flag_if_conversion2
4656 && dbg_cnt (if_after_reload
);
4659 virtual unsigned int execute (function
*)
4665 }; // class pass_if_after_reload
4670 make_pass_if_after_reload (gcc::context
*ctxt
)
4672 return new pass_if_after_reload (ctxt
);