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"
45 #include "shrink-wrap.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_insn
*first_active_insn (basic_block
);
90 static rtx_insn
*last_active_insn (basic_block
, int);
91 static rtx_insn
*find_active_insn_before (basic_block
, rtx_insn
*);
92 static rtx_insn
*find_active_insn_after (basic_block
, rtx_insn
*);
93 static basic_block
block_fallthru (basic_block
);
94 static int cond_exec_process_insns (ce_if_block
*, rtx_insn
*, rtx
, rtx
, int,
96 static rtx
cond_exec_get_condition (rtx_insn
*);
97 static rtx
noce_get_condition (rtx_insn
*, rtx_insn
**, bool);
98 static int noce_operand_ok (const_rtx
);
99 static void merge_if_block (ce_if_block
*);
100 static int find_cond_trap (basic_block
, edge
, edge
);
101 static basic_block
find_if_header (basic_block
, int);
102 static int block_jumps_and_fallthru_p (basic_block
, basic_block
);
103 static int noce_find_if_block (basic_block
, edge
, edge
, int);
104 static int cond_exec_find_if_block (ce_if_block
*);
105 static int find_if_case_1 (basic_block
, edge
, edge
);
106 static int find_if_case_2 (basic_block
, edge
, edge
);
107 static int dead_or_predicable (basic_block
, basic_block
, basic_block
,
109 static void noce_emit_move_insn (rtx
, rtx
);
110 static rtx_insn
*block_has_only_trap (basic_block
);
112 /* Count the number of non-jump active insns in BB. */
115 count_bb_insns (const_basic_block bb
)
118 rtx_insn
*insn
= BB_HEAD (bb
);
122 if (active_insn_p (insn
) && !JUMP_P (insn
))
125 if (insn
== BB_END (bb
))
127 insn
= NEXT_INSN (insn
);
133 /* Determine whether the total insn_rtx_cost on non-jump insns in
134 basic block BB is less than MAX_COST. This function returns
135 false if the cost of any instruction could not be estimated.
137 The cost of the non-jump insns in BB is scaled by REG_BR_PROB_BASE
138 as those insns are being speculated. MAX_COST is scaled with SCALE
139 plus a small fudge factor. */
142 cheap_bb_rtx_cost_p (const_basic_block bb
, int scale
, int max_cost
)
145 rtx_insn
*insn
= BB_HEAD (bb
);
146 bool speed
= optimize_bb_for_speed_p (bb
);
148 /* Set scale to REG_BR_PROB_BASE to void the identical scaling
149 applied to insn_rtx_cost when optimizing for size. Only do
150 this after combine because if-conversion might interfere with
151 passes before combine.
153 Use optimize_function_for_speed_p instead of the pre-defined
154 variable speed to make sure it is set to same value for all
155 basic blocks in one if-conversion transformation. */
156 if (!optimize_function_for_speed_p (cfun
) && ifcvt_after_combine
)
157 scale
= REG_BR_PROB_BASE
;
158 /* Our branch probability/scaling factors are just estimates and don't
159 account for cases where we can get speculation for free and other
160 secondary benefits. So we fudge the scale factor to make speculating
161 appear a little more profitable when optimizing for performance. */
163 scale
+= REG_BR_PROB_BASE
/ 8;
170 if (NONJUMP_INSN_P (insn
))
172 int cost
= insn_rtx_cost (PATTERN (insn
), speed
) * REG_BR_PROB_BASE
;
176 /* If this instruction is the load or set of a "stack" register,
177 such as a floating point register on x87, then the cost of
178 speculatively executing this insn may need to include
179 the additional cost of popping its result off of the
180 register stack. Unfortunately, correctly recognizing and
181 accounting for this additional overhead is tricky, so for
182 now we simply prohibit such speculative execution. */
185 rtx set
= single_set (insn
);
186 if (set
&& STACK_REG_P (SET_DEST (set
)))
192 if (count
>= max_cost
)
195 else if (CALL_P (insn
))
198 if (insn
== BB_END (bb
))
200 insn
= NEXT_INSN (insn
);
206 /* Return the first non-jump active insn in the basic block. */
209 first_active_insn (basic_block bb
)
211 rtx_insn
*insn
= BB_HEAD (bb
);
215 if (insn
== BB_END (bb
))
217 insn
= NEXT_INSN (insn
);
220 while (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
222 if (insn
== BB_END (bb
))
224 insn
= NEXT_INSN (insn
);
233 /* Return the last non-jump active (non-jump) insn in the basic block. */
236 last_active_insn (basic_block bb
, int skip_use_p
)
238 rtx_insn
*insn
= BB_END (bb
);
239 rtx_insn
*head
= BB_HEAD (bb
);
243 || DEBUG_INSN_P (insn
)
245 && NONJUMP_INSN_P (insn
)
246 && GET_CODE (PATTERN (insn
)) == USE
))
250 insn
= PREV_INSN (insn
);
259 /* Return the active insn before INSN inside basic block CURR_BB. */
262 find_active_insn_before (basic_block curr_bb
, rtx_insn
*insn
)
264 if (!insn
|| insn
== BB_HEAD (curr_bb
))
267 while ((insn
= PREV_INSN (insn
)) != NULL_RTX
)
269 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
272 /* No other active insn all the way to the start of the basic block. */
273 if (insn
== BB_HEAD (curr_bb
))
280 /* Return the active insn after INSN inside basic block CURR_BB. */
283 find_active_insn_after (basic_block curr_bb
, rtx_insn
*insn
)
285 if (!insn
|| insn
== BB_END (curr_bb
))
288 while ((insn
= NEXT_INSN (insn
)) != NULL_RTX
)
290 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
293 /* No other active insn all the way to the end of the basic block. */
294 if (insn
== BB_END (curr_bb
))
301 /* Return the basic block reached by falling though the basic block BB. */
304 block_fallthru (basic_block bb
)
306 edge e
= find_fallthru_edge (bb
->succs
);
308 return (e
) ? e
->dest
: NULL_BLOCK
;
311 /* Return true if RTXs A and B can be safely interchanged. */
314 rtx_interchangeable_p (const_rtx a
, const_rtx b
)
316 if (!rtx_equal_p (a
, b
))
319 if (GET_CODE (a
) != MEM
)
322 /* A dead type-unsafe memory reference is legal, but a live type-unsafe memory
323 reference is not. Interchanging a dead type-unsafe memory reference with
324 a live type-safe one creates a live type-unsafe memory reference, in other
325 words, it makes the program illegal.
326 We check here conservatively whether the two memory references have equal
327 memory attributes. */
329 return mem_attrs_eq_p (get_mem_attrs (a
), get_mem_attrs (b
));
333 /* Go through a bunch of insns, converting them to conditional
334 execution format if possible. Return TRUE if all of the non-note
335 insns were processed. */
338 cond_exec_process_insns (ce_if_block
*ce_info ATTRIBUTE_UNUSED
,
339 /* if block information */rtx_insn
*start
,
340 /* first insn to look at */rtx end
,
341 /* last insn to look at */rtx test
,
342 /* conditional execution test */int prob_val
,
343 /* probability of branch taken. */int mod_ok
)
345 int must_be_last
= FALSE
;
353 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
355 /* dwarf2out can't cope with conditional prologues. */
356 if (NOTE_P (insn
) && NOTE_KIND (insn
) == NOTE_INSN_PROLOGUE_END
)
359 if (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
362 gcc_assert (NONJUMP_INSN_P (insn
) || CALL_P (insn
));
364 /* dwarf2out can't cope with conditional unwind info. */
365 if (RTX_FRAME_RELATED_P (insn
))
368 /* Remove USE insns that get in the way. */
369 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
371 /* ??? Ug. Actually unlinking the thing is problematic,
372 given what we'd have to coordinate with our callers. */
373 SET_INSN_DELETED (insn
);
377 /* Last insn wasn't last? */
381 if (modified_in_p (test
, insn
))
388 /* Now build the conditional form of the instruction. */
389 pattern
= PATTERN (insn
);
390 xtest
= copy_rtx (test
);
392 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
394 if (GET_CODE (pattern
) == COND_EXEC
)
396 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
399 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
400 COND_EXEC_TEST (pattern
));
401 pattern
= COND_EXEC_CODE (pattern
);
404 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
406 /* If the machine needs to modify the insn being conditionally executed,
407 say for example to force a constant integer operand into a temp
408 register, do so here. */
409 #ifdef IFCVT_MODIFY_INSN
410 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
415 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
417 if (CALL_P (insn
) && prob_val
>= 0)
418 validate_change (insn
, ®_NOTES (insn
),
419 gen_rtx_INT_LIST ((enum machine_mode
) REG_BR_PROB
,
420 prob_val
, REG_NOTES (insn
)), 1);
430 /* Return the condition for a jump. Do not do any special processing. */
433 cond_exec_get_condition (rtx_insn
*jump
)
437 if (any_condjump_p (jump
))
438 test_if
= SET_SRC (pc_set (jump
));
441 cond
= XEXP (test_if
, 0);
443 /* If this branches to JUMP_LABEL when the condition is false,
444 reverse the condition. */
445 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
446 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
448 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
452 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
459 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
460 to conditional execution. Return TRUE if we were successful at
461 converting the block. */
464 cond_exec_process_if_block (ce_if_block
* ce_info
,
465 /* if block information */int do_multiple_p
)
467 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
468 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
469 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
470 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
471 rtx_insn
*then_start
; /* first insn in THEN block */
472 rtx_insn
*then_end
; /* last insn + 1 in THEN block */
473 rtx_insn
*else_start
= NULL
; /* first insn in ELSE block or NULL */
474 rtx_insn
*else_end
= NULL
; /* last insn + 1 in ELSE block */
475 int max
; /* max # of insns to convert. */
476 int then_mod_ok
; /* whether conditional mods are ok in THEN */
477 rtx true_expr
; /* test for else block insns */
478 rtx false_expr
; /* test for then block insns */
479 int true_prob_val
; /* probability of else block */
480 int false_prob_val
; /* probability of then block */
481 rtx_insn
*then_last_head
= NULL
; /* Last match at the head of THEN */
482 rtx_insn
*else_last_head
= NULL
; /* Last match at the head of ELSE */
483 rtx_insn
*then_first_tail
= NULL
; /* First match at the tail of THEN */
484 rtx_insn
*else_first_tail
= NULL
; /* First match at the tail of ELSE */
485 int then_n_insns
, else_n_insns
, n_insns
;
486 enum rtx_code false_code
;
489 /* If test is comprised of && or || elements, and we've failed at handling
490 all of them together, just use the last test if it is the special case of
491 && elements without an ELSE block. */
492 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
494 if (else_bb
|| ! ce_info
->and_and_p
)
497 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
498 ce_info
->num_multiple_test_blocks
= 0;
499 ce_info
->num_and_and_blocks
= 0;
500 ce_info
->num_or_or_blocks
= 0;
503 /* Find the conditional jump to the ELSE or JOIN part, and isolate
505 test_expr
= cond_exec_get_condition (BB_END (test_bb
));
509 /* If the conditional jump is more than just a conditional jump,
510 then we can not do conditional execution conversion on this block. */
511 if (! onlyjump_p (BB_END (test_bb
)))
514 /* Collect the bounds of where we're to search, skipping any labels, jumps
515 and notes at the beginning and end of the block. Then count the total
516 number of insns and see if it is small enough to convert. */
517 then_start
= first_active_insn (then_bb
);
518 then_end
= last_active_insn (then_bb
, TRUE
);
519 then_n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
520 n_insns
= then_n_insns
;
521 max
= MAX_CONDITIONAL_EXECUTE
;
528 else_start
= first_active_insn (else_bb
);
529 else_end
= last_active_insn (else_bb
, TRUE
);
530 else_n_insns
= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
531 n_insns
+= else_n_insns
;
533 /* Look for matching sequences at the head and tail of the two blocks,
534 and limit the range of insns to be converted if possible. */
535 n_matching
= flow_find_cross_jump (then_bb
, else_bb
,
536 &then_first_tail
, &else_first_tail
,
538 if (then_first_tail
== BB_HEAD (then_bb
))
539 then_start
= then_end
= NULL
;
540 if (else_first_tail
== BB_HEAD (else_bb
))
541 else_start
= else_end
= NULL
;
546 then_end
= find_active_insn_before (then_bb
, then_first_tail
);
548 else_end
= find_active_insn_before (else_bb
, else_first_tail
);
549 n_insns
-= 2 * n_matching
;
554 && then_n_insns
> n_matching
555 && else_n_insns
> n_matching
)
557 int longest_match
= MIN (then_n_insns
- n_matching
,
558 else_n_insns
- n_matching
);
560 = flow_find_head_matching_sequence (then_bb
, else_bb
,
569 /* We won't pass the insns in the head sequence to
570 cond_exec_process_insns, so we need to test them here
571 to make sure that they don't clobber the condition. */
572 for (insn
= BB_HEAD (then_bb
);
573 insn
!= NEXT_INSN (then_last_head
);
574 insn
= NEXT_INSN (insn
))
575 if (!LABEL_P (insn
) && !NOTE_P (insn
)
576 && !DEBUG_INSN_P (insn
)
577 && modified_in_p (test_expr
, insn
))
581 if (then_last_head
== then_end
)
582 then_start
= then_end
= NULL
;
583 if (else_last_head
== else_end
)
584 else_start
= else_end
= NULL
;
589 then_start
= find_active_insn_after (then_bb
, then_last_head
);
591 else_start
= find_active_insn_after (else_bb
, else_last_head
);
592 n_insns
-= 2 * n_matching
;
600 /* Map test_expr/test_jump into the appropriate MD tests to use on
601 the conditionally executed code. */
603 true_expr
= test_expr
;
605 false_code
= reversed_comparison_code (true_expr
, BB_END (test_bb
));
606 if (false_code
!= UNKNOWN
)
607 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
608 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
610 false_expr
= NULL_RTX
;
612 #ifdef IFCVT_MODIFY_TESTS
613 /* If the machine description needs to modify the tests, such as setting a
614 conditional execution register from a comparison, it can do so here. */
615 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
617 /* See if the conversion failed. */
618 if (!true_expr
|| !false_expr
)
622 note
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
625 true_prob_val
= XINT (note
, 0);
626 false_prob_val
= REG_BR_PROB_BASE
- true_prob_val
;
634 /* If we have && or || tests, do them here. These tests are in the adjacent
635 blocks after the first block containing the test. */
636 if (ce_info
->num_multiple_test_blocks
> 0)
638 basic_block bb
= test_bb
;
639 basic_block last_test_bb
= ce_info
->last_test_bb
;
646 rtx_insn
*start
, *end
;
648 enum rtx_code f_code
;
650 bb
= block_fallthru (bb
);
651 start
= first_active_insn (bb
);
652 end
= last_active_insn (bb
, TRUE
);
654 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
655 false_prob_val
, FALSE
))
658 /* If the conditional jump is more than just a conditional jump, then
659 we can not do conditional execution conversion on this block. */
660 if (! onlyjump_p (BB_END (bb
)))
663 /* Find the conditional jump and isolate the test. */
664 t
= cond_exec_get_condition (BB_END (bb
));
668 f_code
= reversed_comparison_code (t
, BB_END (bb
));
669 if (f_code
== UNKNOWN
)
672 f
= gen_rtx_fmt_ee (f_code
, GET_MODE (t
), XEXP (t
, 0), XEXP (t
, 1));
673 if (ce_info
->and_and_p
)
675 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
676 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
680 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
681 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
684 /* If the machine description needs to modify the tests, such as
685 setting a conditional execution register from a comparison, it can
687 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
688 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
690 /* See if the conversion failed. */
698 while (bb
!= last_test_bb
);
701 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
702 on then THEN block. */
703 then_mod_ok
= (else_bb
== NULL_BLOCK
);
705 /* Go through the THEN and ELSE blocks converting the insns if possible
706 to conditional execution. */
710 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
711 false_expr
, false_prob_val
,
715 if (else_bb
&& else_end
716 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
717 true_expr
, true_prob_val
, TRUE
))
720 /* If we cannot apply the changes, fail. Do not go through the normal fail
721 processing, since apply_change_group will call cancel_changes. */
722 if (! apply_change_group ())
724 #ifdef IFCVT_MODIFY_CANCEL
725 /* Cancel any machine dependent changes. */
726 IFCVT_MODIFY_CANCEL (ce_info
);
731 #ifdef IFCVT_MODIFY_FINAL
732 /* Do any machine dependent final modifications. */
733 IFCVT_MODIFY_FINAL (ce_info
);
736 /* Conversion succeeded. */
738 fprintf (dump_file
, "%d insn%s converted to conditional execution.\n",
739 n_insns
, (n_insns
== 1) ? " was" : "s were");
741 /* Merge the blocks! If we had matching sequences, make sure to delete one
742 copy at the appropriate location first: delete the copy in the THEN branch
743 for a tail sequence so that the remaining one is executed last for both
744 branches, and delete the copy in the ELSE branch for a head sequence so
745 that the remaining one is executed first for both branches. */
748 rtx_insn
*from
= then_first_tail
;
750 from
= find_active_insn_after (then_bb
, from
);
751 delete_insn_chain (from
, BB_END (then_bb
), false);
754 delete_insn_chain (first_active_insn (else_bb
), else_last_head
, false);
756 merge_if_block (ce_info
);
757 cond_exec_changed_p
= TRUE
;
761 #ifdef IFCVT_MODIFY_CANCEL
762 /* Cancel any machine dependent changes. */
763 IFCVT_MODIFY_CANCEL (ce_info
);
770 /* Used by noce_process_if_block to communicate with its subroutines.
772 The subroutines know that A and B may be evaluated freely. They
773 know that X is a register. They should insert new instructions
774 before cond_earliest. */
778 /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block. */
779 basic_block test_bb
, then_bb
, else_bb
, join_bb
;
781 /* The jump that ends TEST_BB. */
784 /* The jump condition. */
787 /* New insns should be inserted before this one. */
788 rtx_insn
*cond_earliest
;
790 /* Insns in the THEN and ELSE block. There is always just this
791 one insns in those blocks. The insns are single_set insns.
792 If there was no ELSE block, INSN_B is the last insn before
793 COND_EARLIEST, or NULL_RTX. In the former case, the insn
794 operands are still valid, as if INSN_B was moved down below
796 rtx_insn
*insn_a
, *insn_b
;
798 /* The SET_SRC of INSN_A and INSN_B. */
801 /* The SET_DEST of INSN_A. */
804 /* True if this if block is not canonical. In the canonical form of
805 if blocks, the THEN_BB is the block reached via the fallthru edge
806 from TEST_BB. For the noce transformations, we allow the symmetric
808 bool then_else_reversed
;
810 /* Estimated cost of the particular branch instruction. */
814 static rtx
noce_emit_store_flag (struct noce_if_info
*, rtx
, int, int);
815 static int noce_try_move (struct noce_if_info
*);
816 static int noce_try_store_flag (struct noce_if_info
*);
817 static int noce_try_addcc (struct noce_if_info
*);
818 static int noce_try_store_flag_constants (struct noce_if_info
*);
819 static int noce_try_store_flag_mask (struct noce_if_info
*);
820 static rtx
noce_emit_cmove (struct noce_if_info
*, rtx
, enum rtx_code
, rtx
,
822 static int noce_try_cmove (struct noce_if_info
*);
823 static int noce_try_cmove_arith (struct noce_if_info
*);
824 static rtx
noce_get_alt_condition (struct noce_if_info
*, rtx
, rtx_insn
**);
825 static int noce_try_minmax (struct noce_if_info
*);
826 static int noce_try_abs (struct noce_if_info
*);
827 static int noce_try_sign_mask (struct noce_if_info
*);
829 /* Helper function for noce_try_store_flag*. */
832 noce_emit_store_flag (struct noce_if_info
*if_info
, rtx x
, int reversep
,
835 rtx cond
= if_info
->cond
;
839 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
840 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
842 /* If earliest == jump, or when the condition is complex, try to
843 build the store_flag insn directly. */
847 rtx set
= pc_set (if_info
->jump
);
848 cond
= XEXP (SET_SRC (set
), 0);
849 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
850 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
))
851 reversep
= !reversep
;
852 if (if_info
->then_else_reversed
)
853 reversep
= !reversep
;
857 code
= reversed_comparison_code (cond
, if_info
->jump
);
859 code
= GET_CODE (cond
);
861 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
862 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
864 rtx src
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
866 rtx set
= gen_rtx_SET (VOIDmode
, x
, src
);
869 rtx_insn
*insn
= emit_insn (set
);
871 if (recog_memoized (insn
) >= 0)
873 rtx_insn
*seq
= get_insns ();
877 if_info
->cond_earliest
= if_info
->jump
;
885 /* Don't even try if the comparison operands or the mode of X are weird. */
886 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
889 return emit_store_flag (x
, code
, XEXP (cond
, 0),
890 XEXP (cond
, 1), VOIDmode
,
891 (code
== LTU
|| code
== LEU
892 || code
== GEU
|| code
== GTU
), normalize
);
895 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
896 X is the destination/target and Y is the value to copy. */
899 noce_emit_move_insn (rtx x
, rtx y
)
901 enum machine_mode outmode
;
905 if (GET_CODE (x
) != STRICT_LOW_PART
)
907 rtx_insn
*seq
, *insn
;
912 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
913 otherwise construct a suitable SET pattern ourselves. */
914 insn
= (OBJECT_P (y
) || CONSTANT_P (y
) || GET_CODE (y
) == SUBREG
)
915 ? emit_move_insn (x
, y
)
916 : emit_insn (gen_rtx_SET (VOIDmode
, x
, y
));
920 if (recog_memoized (insn
) <= 0)
922 if (GET_CODE (x
) == ZERO_EXTRACT
)
924 rtx op
= XEXP (x
, 0);
925 unsigned HOST_WIDE_INT size
= INTVAL (XEXP (x
, 1));
926 unsigned HOST_WIDE_INT start
= INTVAL (XEXP (x
, 2));
928 /* store_bit_field expects START to be relative to
929 BYTES_BIG_ENDIAN and adjusts this value for machines with
930 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
931 invoke store_bit_field again it is necessary to have the START
932 value from the first call. */
933 if (BITS_BIG_ENDIAN
!= BYTES_BIG_ENDIAN
)
936 start
= BITS_PER_UNIT
- start
- size
;
939 gcc_assert (REG_P (op
));
940 start
= BITS_PER_WORD
- start
- size
;
944 gcc_assert (start
< (MEM_P (op
) ? BITS_PER_UNIT
: BITS_PER_WORD
));
945 store_bit_field (op
, size
, start
, 0, 0, GET_MODE (x
), y
);
949 switch (GET_RTX_CLASS (GET_CODE (y
)))
952 ot
= code_to_optab (GET_CODE (y
));
956 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
957 if (target
!= NULL_RTX
)
960 emit_move_insn (x
, target
);
969 ot
= code_to_optab (GET_CODE (y
));
973 target
= expand_binop (GET_MODE (y
), ot
,
974 XEXP (y
, 0), XEXP (y
, 1),
976 if (target
!= NULL_RTX
)
979 emit_move_insn (x
, target
);
996 inner
= XEXP (outer
, 0);
997 outmode
= GET_MODE (outer
);
998 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
999 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
,
1003 /* Return sequence of instructions generated by if conversion. This
1004 function calls end_sequence() to end the current stream, ensures
1005 that are instructions are unshared, recognizable non-jump insns.
1006 On failure, this function returns a NULL_RTX. */
1009 end_ifcvt_sequence (struct noce_if_info
*if_info
)
1012 rtx_insn
*seq
= get_insns ();
1014 set_used_flags (if_info
->x
);
1015 set_used_flags (if_info
->cond
);
1016 set_used_flags (if_info
->a
);
1017 set_used_flags (if_info
->b
);
1018 unshare_all_rtl_in_chain (seq
);
1021 /* Make sure that all of the instructions emitted are recognizable,
1022 and that we haven't introduced a new jump instruction.
1023 As an exercise for the reader, build a general mechanism that
1024 allows proper placement of required clobbers. */
1025 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
1027 || recog_memoized (insn
) == -1)
1033 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
1034 "if (a == b) x = a; else x = b" into "x = b". */
1037 noce_try_move (struct noce_if_info
*if_info
)
1039 rtx cond
= if_info
->cond
;
1040 enum rtx_code code
= GET_CODE (cond
);
1044 if (code
!= NE
&& code
!= EQ
)
1047 /* This optimization isn't valid if either A or B could be a NaN
1048 or a signed zero. */
1049 if (HONOR_NANS (GET_MODE (if_info
->x
))
1050 || HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
1053 /* Check whether the operands of the comparison are A and in
1055 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
1056 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
1057 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
1058 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
1060 if (!rtx_interchangeable_p (if_info
->a
, if_info
->b
))
1063 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
1065 /* Avoid generating the move if the source is the destination. */
1066 if (! rtx_equal_p (if_info
->x
, y
))
1069 noce_emit_move_insn (if_info
->x
, y
);
1070 seq
= end_ifcvt_sequence (if_info
);
1074 emit_insn_before_setloc (seq
, if_info
->jump
,
1075 INSN_LOCATION (if_info
->insn_a
));
1082 /* Convert "if (test) x = 1; else x = 0".
1084 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
1085 tried in noce_try_store_flag_constants after noce_try_cmove has had
1086 a go at the conversion. */
1089 noce_try_store_flag (struct noce_if_info
*if_info
)
1095 if (CONST_INT_P (if_info
->b
)
1096 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
1097 && if_info
->a
== const0_rtx
)
1099 else if (if_info
->b
== const0_rtx
1100 && CONST_INT_P (if_info
->a
)
1101 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
1102 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1110 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
1113 if (target
!= if_info
->x
)
1114 noce_emit_move_insn (if_info
->x
, target
);
1116 seq
= end_ifcvt_sequence (if_info
);
1120 emit_insn_before_setloc (seq
, if_info
->jump
,
1121 INSN_LOCATION (if_info
->insn_a
));
1131 /* Convert "if (test) x = a; else x = b", for A and B constant. */
1134 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
1139 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
1140 int normalize
, can_reverse
;
1141 enum machine_mode mode
;
1143 if (CONST_INT_P (if_info
->a
)
1144 && CONST_INT_P (if_info
->b
))
1146 mode
= GET_MODE (if_info
->x
);
1147 ifalse
= INTVAL (if_info
->a
);
1148 itrue
= INTVAL (if_info
->b
);
1150 diff
= (unsigned HOST_WIDE_INT
) itrue
- ifalse
;
1151 /* Make sure we can represent the difference between the two values. */
1153 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
1156 diff
= trunc_int_for_mode (diff
, mode
);
1158 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1162 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1164 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
1165 && (STORE_FLAG_VALUE
== 1
1166 || if_info
->branch_cost
>= 2))
1168 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
1169 && (STORE_FLAG_VALUE
== 1 || if_info
->branch_cost
>= 2))
1170 normalize
= 1, reversep
= 1;
1171 else if (itrue
== -1
1172 && (STORE_FLAG_VALUE
== -1
1173 || if_info
->branch_cost
>= 2))
1175 else if (ifalse
== -1 && can_reverse
1176 && (STORE_FLAG_VALUE
== -1 || if_info
->branch_cost
>= 2))
1177 normalize
= -1, reversep
= 1;
1178 else if ((if_info
->branch_cost
>= 2 && STORE_FLAG_VALUE
== -1)
1179 || if_info
->branch_cost
>= 3)
1186 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
1187 diff
= trunc_int_for_mode (-(unsigned HOST_WIDE_INT
) diff
, mode
);
1191 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
1198 /* if (test) x = 3; else x = 4;
1199 => x = 3 + (test == 0); */
1200 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1202 target
= expand_simple_binop (mode
,
1203 (diff
== STORE_FLAG_VALUE
1205 gen_int_mode (ifalse
, mode
), target
,
1206 if_info
->x
, 0, OPTAB_WIDEN
);
1209 /* if (test) x = 8; else x = 0;
1210 => x = (test != 0) << 3; */
1211 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
1213 target
= expand_simple_binop (mode
, ASHIFT
,
1214 target
, GEN_INT (tmp
), if_info
->x
, 0,
1218 /* if (test) x = -1; else x = b;
1219 => x = -(test != 0) | b; */
1220 else if (itrue
== -1)
1222 target
= expand_simple_binop (mode
, IOR
,
1223 target
, gen_int_mode (ifalse
, mode
),
1224 if_info
->x
, 0, OPTAB_WIDEN
);
1227 /* if (test) x = a; else x = b;
1228 => x = (-(test != 0) & (b - a)) + a; */
1231 target
= expand_simple_binop (mode
, AND
,
1232 target
, gen_int_mode (diff
, mode
),
1233 if_info
->x
, 0, OPTAB_WIDEN
);
1235 target
= expand_simple_binop (mode
, PLUS
,
1236 target
, gen_int_mode (ifalse
, mode
),
1237 if_info
->x
, 0, OPTAB_WIDEN
);
1246 if (target
!= if_info
->x
)
1247 noce_emit_move_insn (if_info
->x
, target
);
1249 seq
= end_ifcvt_sequence (if_info
);
1253 emit_insn_before_setloc (seq
, if_info
->jump
,
1254 INSN_LOCATION (if_info
->insn_a
));
1261 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1262 similarly for "foo--". */
1265 noce_try_addcc (struct noce_if_info
*if_info
)
1269 int subtract
, normalize
;
1271 if (GET_CODE (if_info
->a
) == PLUS
1272 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1273 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1276 rtx cond
= if_info
->cond
;
1277 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1279 /* First try to use addcc pattern. */
1280 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1281 && general_operand (XEXP (cond
, 1), VOIDmode
))
1284 target
= emit_conditional_add (if_info
->x
, code
,
1289 XEXP (if_info
->a
, 1),
1290 GET_MODE (if_info
->x
),
1291 (code
== LTU
|| code
== GEU
1292 || code
== LEU
|| code
== GTU
));
1295 if (target
!= if_info
->x
)
1296 noce_emit_move_insn (if_info
->x
, target
);
1298 seq
= end_ifcvt_sequence (if_info
);
1302 emit_insn_before_setloc (seq
, if_info
->jump
,
1303 INSN_LOCATION (if_info
->insn_a
));
1309 /* If that fails, construct conditional increment or decrement using
1311 if (if_info
->branch_cost
>= 2
1312 && (XEXP (if_info
->a
, 1) == const1_rtx
1313 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1316 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1317 subtract
= 0, normalize
= 0;
1318 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1319 subtract
= 1, normalize
= 0;
1321 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1324 target
= noce_emit_store_flag (if_info
,
1325 gen_reg_rtx (GET_MODE (if_info
->x
)),
1329 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1330 subtract
? MINUS
: PLUS
,
1331 if_info
->b
, target
, if_info
->x
,
1335 if (target
!= if_info
->x
)
1336 noce_emit_move_insn (if_info
->x
, target
);
1338 seq
= end_ifcvt_sequence (if_info
);
1342 emit_insn_before_setloc (seq
, if_info
->jump
,
1343 INSN_LOCATION (if_info
->insn_a
));
1353 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1356 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1363 if ((if_info
->branch_cost
>= 2
1364 || STORE_FLAG_VALUE
== -1)
1365 && ((if_info
->a
== const0_rtx
1366 && rtx_equal_p (if_info
->b
, if_info
->x
))
1367 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1370 && if_info
->b
== const0_rtx
1371 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1374 target
= noce_emit_store_flag (if_info
,
1375 gen_reg_rtx (GET_MODE (if_info
->x
)),
1378 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1380 target
, if_info
->x
, 0,
1385 if (target
!= if_info
->x
)
1386 noce_emit_move_insn (if_info
->x
, target
);
1388 seq
= end_ifcvt_sequence (if_info
);
1392 emit_insn_before_setloc (seq
, if_info
->jump
,
1393 INSN_LOCATION (if_info
->insn_a
));
1403 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1406 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1407 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1409 rtx target ATTRIBUTE_UNUSED
;
1410 int unsignedp ATTRIBUTE_UNUSED
;
1412 /* If earliest == jump, try to build the cmove insn directly.
1413 This is helpful when combine has created some complex condition
1414 (like for alpha's cmovlbs) that we can't hope to regenerate
1415 through the normal interface. */
1417 if (if_info
->cond_earliest
== if_info
->jump
)
1419 rtx cond
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1420 rtx if_then_else
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
),
1421 cond
, vtrue
, vfalse
);
1422 rtx set
= gen_rtx_SET (VOIDmode
, x
, if_then_else
);
1425 rtx_insn
*insn
= emit_insn (set
);
1427 if (recog_memoized (insn
) >= 0)
1429 rtx_insn
*seq
= get_insns ();
1439 /* Don't even try if the comparison operands are weird. */
1440 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1441 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1444 #if HAVE_conditional_move
1445 unsignedp
= (code
== LTU
|| code
== GEU
1446 || code
== LEU
|| code
== GTU
);
1448 target
= emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1449 vtrue
, vfalse
, GET_MODE (x
),
1454 /* We might be faced with a situation like:
1457 vtrue = (subreg:M (reg:N VTRUE) BYTE)
1458 vfalse = (subreg:M (reg:N VFALSE) BYTE)
1460 We can't do a conditional move in mode M, but it's possible that we
1461 could do a conditional move in mode N instead and take a subreg of
1464 If we can't create new pseudos, though, don't bother. */
1465 if (reload_completed
)
1468 if (GET_CODE (vtrue
) == SUBREG
&& GET_CODE (vfalse
) == SUBREG
)
1470 rtx reg_vtrue
= SUBREG_REG (vtrue
);
1471 rtx reg_vfalse
= SUBREG_REG (vfalse
);
1472 unsigned int byte_vtrue
= SUBREG_BYTE (vtrue
);
1473 unsigned int byte_vfalse
= SUBREG_BYTE (vfalse
);
1474 rtx promoted_target
;
1476 if (GET_MODE (reg_vtrue
) != GET_MODE (reg_vfalse
)
1477 || byte_vtrue
!= byte_vfalse
1478 || (SUBREG_PROMOTED_VAR_P (vtrue
)
1479 != SUBREG_PROMOTED_VAR_P (vfalse
))
1480 || (SUBREG_PROMOTED_GET (vtrue
)
1481 != SUBREG_PROMOTED_GET (vfalse
)))
1484 promoted_target
= gen_reg_rtx (GET_MODE (reg_vtrue
));
1486 target
= emit_conditional_move (promoted_target
, code
, cmp_a
, cmp_b
,
1487 VOIDmode
, reg_vtrue
, reg_vfalse
,
1488 GET_MODE (reg_vtrue
), unsignedp
);
1489 /* Nope, couldn't do it in that mode either. */
1493 target
= gen_rtx_SUBREG (GET_MODE (vtrue
), promoted_target
, byte_vtrue
);
1494 SUBREG_PROMOTED_VAR_P (target
) = SUBREG_PROMOTED_VAR_P (vtrue
);
1495 SUBREG_PROMOTED_SET (target
, SUBREG_PROMOTED_GET (vtrue
));
1496 emit_move_insn (x
, target
);
1502 /* We'll never get here, as noce_process_if_block doesn't call the
1503 functions involved. Ifdef code, however, should be discouraged
1504 because it leads to typos in the code not selected. However,
1505 emit_conditional_move won't exist either. */
1510 /* Try only simple constants and registers here. More complex cases
1511 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1512 has had a go at it. */
1515 noce_try_cmove (struct noce_if_info
*if_info
)
1521 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1522 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1526 code
= GET_CODE (if_info
->cond
);
1527 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1528 XEXP (if_info
->cond
, 0),
1529 XEXP (if_info
->cond
, 1),
1530 if_info
->a
, if_info
->b
);
1534 if (target
!= if_info
->x
)
1535 noce_emit_move_insn (if_info
->x
, target
);
1537 seq
= end_ifcvt_sequence (if_info
);
1541 emit_insn_before_setloc (seq
, if_info
->jump
,
1542 INSN_LOCATION (if_info
->insn_a
));
1555 /* Try more complex cases involving conditional_move. */
1558 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1564 rtx_insn
*insn_a
, *insn_b
;
1569 rtx_insn
*ifcvt_seq
;
1571 /* A conditional move from two memory sources is equivalent to a
1572 conditional on their addresses followed by a load. Don't do this
1573 early because it'll screw alias analysis. Note that we've
1574 already checked for no side effects. */
1575 /* ??? FIXME: Magic number 5. */
1576 if (cse_not_expected
1577 && MEM_P (a
) && MEM_P (b
)
1578 && MEM_ADDR_SPACE (a
) == MEM_ADDR_SPACE (b
)
1579 && if_info
->branch_cost
>= 5)
1581 enum machine_mode address_mode
= get_address_mode (a
);
1585 x
= gen_reg_rtx (address_mode
);
1589 /* ??? We could handle this if we knew that a load from A or B could
1590 not trap or fault. This is also true if we've already loaded
1591 from the address along the path from ENTRY. */
1592 else if (may_trap_or_fault_p (a
) || may_trap_or_fault_p (b
))
1595 /* if (test) x = a + b; else x = c - d;
1602 code
= GET_CODE (if_info
->cond
);
1603 insn_a
= if_info
->insn_a
;
1604 insn_b
= if_info
->insn_b
;
1606 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1607 if insn_rtx_cost can't be estimated. */
1611 = insn_rtx_cost (PATTERN (insn_a
),
1612 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a
)));
1613 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1622 += insn_rtx_cost (PATTERN (insn_b
),
1623 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b
)));
1624 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1628 /* Possibly rearrange operands to make things come out more natural. */
1629 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1632 if (rtx_equal_p (b
, x
))
1634 else if (general_operand (b
, GET_MODE (b
)))
1641 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1642 tmp
= a
, a
= b
, b
= tmp
;
1643 tmp_insn
= insn_a
, insn_a
= insn_b
, insn_b
= tmp_insn
;
1652 /* If either operand is complex, load it into a register first.
1653 The best way to do this is to copy the original insn. In this
1654 way we preserve any clobbers etc that the insn may have had.
1655 This is of course not possible in the IS_MEM case. */
1656 if (! general_operand (a
, GET_MODE (a
)))
1662 rtx reg
= gen_reg_rtx (GET_MODE (a
));
1663 insn
= emit_insn (gen_rtx_SET (VOIDmode
, reg
, a
));
1666 goto end_seq_and_fail
;
1669 a
= gen_reg_rtx (GET_MODE (a
));
1670 rtx_insn
*copy_of_a
= as_a
<rtx_insn
*> (copy_rtx (insn_a
));
1671 rtx set
= single_set (copy_of_a
);
1673 insn
= emit_insn (PATTERN (copy_of_a
));
1675 if (recog_memoized (insn
) < 0)
1676 goto end_seq_and_fail
;
1678 if (! general_operand (b
, GET_MODE (b
)))
1686 rtx reg
= gen_reg_rtx (GET_MODE (b
));
1687 pat
= gen_rtx_SET (VOIDmode
, reg
, b
);
1690 goto end_seq_and_fail
;
1693 b
= gen_reg_rtx (GET_MODE (b
));
1694 rtx_insn
*copy_of_insn_b
= as_a
<rtx_insn
*> (copy_rtx (insn_b
));
1695 rtx set
= single_set (copy_of_insn_b
);
1697 pat
= PATTERN (copy_of_insn_b
);
1700 /* If insn to set up A clobbers any registers B depends on, try to
1701 swap insn that sets up A with the one that sets up B. If even
1702 that doesn't help, punt. */
1703 last
= get_last_insn ();
1704 if (last
&& modified_in_p (orig_b
, last
))
1706 new_insn
= emit_insn_before (pat
, get_insns ());
1707 if (modified_in_p (orig_a
, new_insn
))
1708 goto end_seq_and_fail
;
1711 new_insn
= emit_insn (pat
);
1713 if (recog_memoized (new_insn
) < 0)
1714 goto end_seq_and_fail
;
1717 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1718 XEXP (if_info
->cond
, 1), a
, b
);
1721 goto end_seq_and_fail
;
1723 /* If we're handling a memory for above, emit the load now. */
1726 rtx mem
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1728 /* Copy over flags as appropriate. */
1729 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1730 MEM_VOLATILE_P (mem
) = 1;
1731 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1732 set_mem_alias_set (mem
, MEM_ALIAS_SET (if_info
->a
));
1734 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1736 gcc_assert (MEM_ADDR_SPACE (if_info
->a
) == MEM_ADDR_SPACE (if_info
->b
));
1737 set_mem_addr_space (mem
, MEM_ADDR_SPACE (if_info
->a
));
1739 noce_emit_move_insn (if_info
->x
, mem
);
1741 else if (target
!= x
)
1742 noce_emit_move_insn (x
, target
);
1744 ifcvt_seq
= end_ifcvt_sequence (if_info
);
1748 emit_insn_before_setloc (ifcvt_seq
, if_info
->jump
,
1749 INSN_LOCATION (if_info
->insn_a
));
1757 /* For most cases, the simplified condition we found is the best
1758 choice, but this is not the case for the min/max/abs transforms.
1759 For these we wish to know that it is A or B in the condition. */
1762 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1763 rtx_insn
**earliest
)
1769 /* If target is already mentioned in the known condition, return it. */
1770 if (reg_mentioned_p (target
, if_info
->cond
))
1772 *earliest
= if_info
->cond_earliest
;
1773 return if_info
->cond
;
1776 set
= pc_set (if_info
->jump
);
1777 cond
= XEXP (SET_SRC (set
), 0);
1779 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1780 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1781 if (if_info
->then_else_reversed
)
1784 /* If we're looking for a constant, try to make the conditional
1785 have that constant in it. There are two reasons why it may
1786 not have the constant we want:
1788 1. GCC may have needed to put the constant in a register, because
1789 the target can't compare directly against that constant. For
1790 this case, we look for a SET immediately before the comparison
1791 that puts a constant in that register.
1793 2. GCC may have canonicalized the conditional, for example
1794 replacing "if x < 4" with "if x <= 3". We can undo that (or
1795 make equivalent types of changes) to get the constants we need
1796 if they're off by one in the right direction. */
1798 if (CONST_INT_P (target
))
1800 enum rtx_code code
= GET_CODE (if_info
->cond
);
1801 rtx op_a
= XEXP (if_info
->cond
, 0);
1802 rtx op_b
= XEXP (if_info
->cond
, 1);
1805 /* First, look to see if we put a constant in a register. */
1806 prev_insn
= prev_nonnote_insn (if_info
->cond_earliest
);
1808 && BLOCK_FOR_INSN (prev_insn
)
1809 == BLOCK_FOR_INSN (if_info
->cond_earliest
)
1810 && INSN_P (prev_insn
)
1811 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1813 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1815 src
= SET_SRC (PATTERN (prev_insn
));
1816 if (CONST_INT_P (src
))
1818 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1820 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1823 if (CONST_INT_P (op_a
))
1828 code
= swap_condition (code
);
1833 /* Now, look to see if we can get the right constant by
1834 adjusting the conditional. */
1835 if (CONST_INT_P (op_b
))
1837 HOST_WIDE_INT desired_val
= INTVAL (target
);
1838 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1843 if (actual_val
== desired_val
+ 1)
1846 op_b
= GEN_INT (desired_val
);
1850 if (actual_val
== desired_val
- 1)
1853 op_b
= GEN_INT (desired_val
);
1857 if (actual_val
== desired_val
- 1)
1860 op_b
= GEN_INT (desired_val
);
1864 if (actual_val
== desired_val
+ 1)
1867 op_b
= GEN_INT (desired_val
);
1875 /* If we made any changes, generate a new conditional that is
1876 equivalent to what we started with, but has the right
1878 if (code
!= GET_CODE (if_info
->cond
)
1879 || op_a
!= XEXP (if_info
->cond
, 0)
1880 || op_b
!= XEXP (if_info
->cond
, 1))
1882 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1883 *earliest
= if_info
->cond_earliest
;
1888 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1889 earliest
, target
, false, true);
1890 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1893 /* We almost certainly searched back to a different place.
1894 Need to re-verify correct lifetimes. */
1896 /* X may not be mentioned in the range (cond_earliest, jump]. */
1897 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1898 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1901 /* A and B may not be modified in the range [cond_earliest, jump). */
1902 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1904 && (modified_in_p (if_info
->a
, insn
)
1905 || modified_in_p (if_info
->b
, insn
)))
1911 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1914 noce_try_minmax (struct noce_if_info
*if_info
)
1917 rtx_insn
*earliest
, *seq
;
1918 enum rtx_code code
, op
;
1921 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1922 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1923 to get the target to tell us... */
1924 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1925 || HONOR_NANS (GET_MODE (if_info
->x
)))
1928 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1932 /* Verify the condition is of the form we expect, and canonicalize
1933 the comparison code. */
1934 code
= GET_CODE (cond
);
1935 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1937 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1940 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1942 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1944 code
= swap_condition (code
);
1949 /* Determine what sort of operation this is. Note that the code is for
1950 a taken branch, so the code->operation mapping appears backwards. */
1983 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1984 if_info
->a
, if_info
->b
,
1985 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1991 if (target
!= if_info
->x
)
1992 noce_emit_move_insn (if_info
->x
, target
);
1994 seq
= end_ifcvt_sequence (if_info
);
1998 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
1999 if_info
->cond
= cond
;
2000 if_info
->cond_earliest
= earliest
;
2005 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
2006 "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
2010 noce_try_abs (struct noce_if_info
*if_info
)
2012 rtx cond
, target
, a
, b
, c
;
2013 rtx_insn
*earliest
, *seq
;
2015 bool one_cmpl
= false;
2017 /* Reject modes with signed zeros. */
2018 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
2021 /* Recognize A and B as constituting an ABS or NABS. The canonical
2022 form is a branch around the negation, taken when the object is the
2023 first operand of a comparison against 0 that evaluates to true. */
2026 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
2028 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
2030 c
= a
; a
= b
; b
= c
;
2033 else if (GET_CODE (a
) == NOT
&& rtx_equal_p (XEXP (a
, 0), b
))
2038 else if (GET_CODE (b
) == NOT
&& rtx_equal_p (XEXP (b
, 0), a
))
2040 c
= a
; a
= b
; b
= c
;
2047 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
2051 /* Verify the condition is of the form we expect. */
2052 if (rtx_equal_p (XEXP (cond
, 0), b
))
2054 else if (rtx_equal_p (XEXP (cond
, 1), b
))
2062 /* Verify that C is zero. Search one step backward for a
2063 REG_EQUAL note or a simple source if necessary. */
2066 rtx set
, insn
= prev_nonnote_insn (earliest
);
2068 && BLOCK_FOR_INSN (insn
) == BLOCK_FOR_INSN (earliest
)
2069 && (set
= single_set (insn
))
2070 && rtx_equal_p (SET_DEST (set
), c
))
2072 rtx note
= find_reg_equal_equiv_note (insn
);
2082 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
2083 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
2084 c
= get_pool_constant (XEXP (c
, 0));
2086 /* Work around funny ideas get_condition has wrt canonicalization.
2087 Note that these rtx constants are known to be CONST_INT, and
2088 therefore imply integer comparisons. */
2089 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
2091 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
2093 else if (c
!= CONST0_RTX (GET_MODE (b
)))
2096 /* Determine what sort of operation this is. */
2097 switch (GET_CODE (cond
))
2116 target
= expand_one_cmpl_abs_nojump (GET_MODE (if_info
->x
), b
,
2119 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
2121 /* ??? It's a quandary whether cmove would be better here, especially
2122 for integers. Perhaps combine will clean things up. */
2123 if (target
&& negate
)
2126 target
= expand_simple_unop (GET_MODE (target
), NOT
, target
,
2129 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
,
2139 if (target
!= if_info
->x
)
2140 noce_emit_move_insn (if_info
->x
, target
);
2142 seq
= end_ifcvt_sequence (if_info
);
2146 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2147 if_info
->cond
= cond
;
2148 if_info
->cond_earliest
= earliest
;
2153 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
2156 noce_try_sign_mask (struct noce_if_info
*if_info
)
2160 enum machine_mode mode
;
2162 bool t_unconditional
;
2164 cond
= if_info
->cond
;
2165 code
= GET_CODE (cond
);
2170 if (if_info
->a
== const0_rtx
)
2172 if ((code
== LT
&& c
== const0_rtx
)
2173 || (code
== LE
&& c
== constm1_rtx
))
2176 else if (if_info
->b
== const0_rtx
)
2178 if ((code
== GE
&& c
== const0_rtx
)
2179 || (code
== GT
&& c
== constm1_rtx
))
2183 if (! t
|| side_effects_p (t
))
2186 /* We currently don't handle different modes. */
2187 mode
= GET_MODE (t
);
2188 if (GET_MODE (m
) != mode
)
2191 /* This is only profitable if T is unconditionally executed/evaluated in the
2192 original insn sequence or T is cheap. The former happens if B is the
2193 non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
2194 INSN_B which can happen for e.g. conditional stores to memory. For the
2195 cost computation use the block TEST_BB where the evaluation will end up
2196 after the transformation. */
2199 && (if_info
->insn_b
== NULL_RTX
2200 || BLOCK_FOR_INSN (if_info
->insn_b
) == if_info
->test_bb
));
2201 if (!(t_unconditional
2202 || (set_src_cost (t
, optimize_bb_for_speed_p (if_info
->test_bb
))
2203 < COSTS_N_INSNS (2))))
2207 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
2208 "(signed) m >> 31" directly. This benefits targets with specialized
2209 insns to obtain the signmask, but still uses ashr_optab otherwise. */
2210 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
2211 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
2220 noce_emit_move_insn (if_info
->x
, t
);
2222 seq
= end_ifcvt_sequence (if_info
);
2226 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2231 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
2235 noce_try_bitop (struct noce_if_info
*if_info
)
2237 rtx cond
, x
, a
, result
;
2239 enum machine_mode mode
;
2244 cond
= if_info
->cond
;
2245 code
= GET_CODE (cond
);
2247 /* Check for no else condition. */
2248 if (! rtx_equal_p (x
, if_info
->b
))
2251 /* Check for a suitable condition. */
2252 if (code
!= NE
&& code
!= EQ
)
2254 if (XEXP (cond
, 1) != const0_rtx
)
2256 cond
= XEXP (cond
, 0);
2258 /* ??? We could also handle AND here. */
2259 if (GET_CODE (cond
) == ZERO_EXTRACT
)
2261 if (XEXP (cond
, 1) != const1_rtx
2262 || !CONST_INT_P (XEXP (cond
, 2))
2263 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
2265 bitnum
= INTVAL (XEXP (cond
, 2));
2266 mode
= GET_MODE (x
);
2267 if (BITS_BIG_ENDIAN
)
2268 bitnum
= GET_MODE_BITSIZE (mode
) - 1 - bitnum
;
2269 if (bitnum
< 0 || bitnum
>= HOST_BITS_PER_WIDE_INT
)
2276 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
2278 /* Check for "if (X & C) x = x op C". */
2279 if (! rtx_equal_p (x
, XEXP (a
, 0))
2280 || !CONST_INT_P (XEXP (a
, 1))
2281 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2282 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
2285 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
2286 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
2287 if (GET_CODE (a
) == IOR
)
2288 result
= (code
== NE
) ? a
: NULL_RTX
;
2289 else if (code
== NE
)
2291 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
2292 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
2293 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
2297 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2298 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
2299 result
= simplify_gen_binary (AND
, mode
, x
, result
);
2302 else if (GET_CODE (a
) == AND
)
2304 /* Check for "if (X & C) x &= ~C". */
2305 if (! rtx_equal_p (x
, XEXP (a
, 0))
2306 || !CONST_INT_P (XEXP (a
, 1))
2307 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2308 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
2311 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2312 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2313 result
= (code
== EQ
) ? a
: NULL_RTX
;
2321 noce_emit_move_insn (x
, result
);
2322 seq
= end_ifcvt_sequence (if_info
);
2326 emit_insn_before_setloc (seq
, if_info
->jump
,
2327 INSN_LOCATION (if_info
->insn_a
));
2333 /* Similar to get_condition, only the resulting condition must be
2334 valid at JUMP, instead of at EARLIEST.
2336 If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
2337 THEN block of the caller, and we have to reverse the condition. */
2340 noce_get_condition (rtx_insn
*jump
, rtx_insn
**earliest
, bool then_else_reversed
)
2345 if (! any_condjump_p (jump
))
2348 set
= pc_set (jump
);
2350 /* If this branches to JUMP_LABEL when the condition is false,
2351 reverse the condition. */
2352 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
2353 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
2355 /* We may have to reverse because the caller's if block is not canonical,
2356 i.e. the THEN block isn't the fallthrough block for the TEST block
2357 (see find_if_header). */
2358 if (then_else_reversed
)
2361 /* If the condition variable is a register and is MODE_INT, accept it. */
2363 cond
= XEXP (SET_SRC (set
), 0);
2364 tmp
= XEXP (cond
, 0);
2365 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
2366 && (GET_MODE (tmp
) != BImode
2367 || !targetm
.small_register_classes_for_mode_p (BImode
)))
2372 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
2373 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2377 /* Otherwise, fall back on canonicalize_condition to do the dirty
2378 work of manipulating MODE_CC values and COMPARE rtx codes. */
2379 tmp
= canonicalize_condition (jump
, cond
, reverse
, earliest
,
2380 NULL_RTX
, false, true);
2382 /* We don't handle side-effects in the condition, like handling
2383 REG_INC notes and making sure no duplicate conditions are emitted. */
2384 if (tmp
!= NULL_RTX
&& side_effects_p (tmp
))
2390 /* Return true if OP is ok for if-then-else processing. */
2393 noce_operand_ok (const_rtx op
)
2395 if (side_effects_p (op
))
2398 /* We special-case memories, so handle any of them with
2399 no address side effects. */
2401 return ! side_effects_p (XEXP (op
, 0));
2403 return ! may_trap_p (op
);
2406 /* Return true if a write into MEM may trap or fault. */
2409 noce_mem_write_may_trap_or_fault_p (const_rtx mem
)
2413 if (MEM_READONLY_P (mem
))
2416 if (may_trap_or_fault_p (mem
))
2419 addr
= XEXP (mem
, 0);
2421 /* Call target hook to avoid the effects of -fpic etc.... */
2422 addr
= targetm
.delegitimize_address (addr
);
2425 switch (GET_CODE (addr
))
2433 addr
= XEXP (addr
, 0);
2437 addr
= XEXP (addr
, 1);
2440 if (CONST_INT_P (XEXP (addr
, 1)))
2441 addr
= XEXP (addr
, 0);
2448 if (SYMBOL_REF_DECL (addr
)
2449 && decl_readonly_section (SYMBOL_REF_DECL (addr
), 0))
2459 /* Return whether we can use store speculation for MEM. TOP_BB is the
2460 basic block above the conditional block where we are considering
2461 doing the speculative store. We look for whether MEM is set
2462 unconditionally later in the function. */
2465 noce_can_store_speculate_p (basic_block top_bb
, const_rtx mem
)
2467 basic_block dominator
;
2469 for (dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, top_bb
);
2471 dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, dominator
))
2475 FOR_BB_INSNS (dominator
, insn
)
2477 /* If we see something that might be a memory barrier, we
2478 have to stop looking. Even if the MEM is set later in
2479 the function, we still don't want to set it
2480 unconditionally before the barrier. */
2482 && (volatile_insn_p (PATTERN (insn
))
2483 || (CALL_P (insn
) && (!RTL_CONST_CALL_P (insn
)))))
2486 if (memory_must_be_modified_in_insn_p (mem
, insn
))
2488 if (modified_in_p (XEXP (mem
, 0), insn
))
2497 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2498 it without using conditional execution. Return TRUE if we were successful
2499 at converting the block. */
2502 noce_process_if_block (struct noce_if_info
*if_info
)
2504 basic_block test_bb
= if_info
->test_bb
; /* test block */
2505 basic_block then_bb
= if_info
->then_bb
; /* THEN */
2506 basic_block else_bb
= if_info
->else_bb
; /* ELSE or NULL */
2507 basic_block join_bb
= if_info
->join_bb
; /* JOIN */
2508 rtx_insn
*jump
= if_info
->jump
;
2509 rtx cond
= if_info
->cond
;
2510 rtx_insn
*insn_a
, *insn_b
;
2512 rtx orig_x
, x
, a
, b
;
2514 /* We're looking for patterns of the form
2516 (1) if (...) x = a; else x = b;
2517 (2) x = b; if (...) x = a;
2518 (3) if (...) x = a; // as if with an initial x = x.
2520 The later patterns require jumps to be more expensive.
2522 ??? For future expansion, look for multiple X in such patterns. */
2524 /* Look for one of the potential sets. */
2525 insn_a
= first_active_insn (then_bb
);
2527 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2528 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2531 x
= SET_DEST (set_a
);
2532 a
= SET_SRC (set_a
);
2534 /* Look for the other potential set. Make sure we've got equivalent
2536 /* ??? This is overconservative. Storing to two different mems is
2537 as easy as conditionally computing the address. Storing to a
2538 single mem merely requires a scratch memory to use as one of the
2539 destination addresses; often the memory immediately below the
2540 stack pointer is available for this. */
2544 insn_b
= first_active_insn (else_bb
);
2546 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2547 || (set_b
= single_set (insn_b
)) == NULL_RTX
2548 || ! rtx_interchangeable_p (x
, SET_DEST (set_b
)))
2553 insn_b
= prev_nonnote_nondebug_insn (if_info
->cond_earliest
);
2554 /* We're going to be moving the evaluation of B down from above
2555 COND_EARLIEST to JUMP. Make sure the relevant data is still
2558 || BLOCK_FOR_INSN (insn_b
) != BLOCK_FOR_INSN (if_info
->cond_earliest
)
2559 || !NONJUMP_INSN_P (insn_b
)
2560 || (set_b
= single_set (insn_b
)) == NULL_RTX
2561 || ! rtx_interchangeable_p (x
, SET_DEST (set_b
))
2562 || ! noce_operand_ok (SET_SRC (set_b
))
2563 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2564 || modified_between_p (SET_SRC (set_b
), insn_b
, jump
)
2565 /* Avoid extending the lifetime of hard registers on small
2566 register class machines. */
2567 || (REG_P (SET_SRC (set_b
))
2568 && HARD_REGISTER_P (SET_SRC (set_b
))
2569 && targetm
.small_register_classes_for_mode_p
2570 (GET_MODE (SET_SRC (set_b
))))
2571 /* Likewise with X. In particular this can happen when
2572 noce_get_condition looks farther back in the instruction
2573 stream than one might expect. */
2574 || reg_overlap_mentioned_p (x
, cond
)
2575 || reg_overlap_mentioned_p (x
, a
)
2576 || modified_between_p (x
, insn_b
, jump
))
2583 /* If x has side effects then only the if-then-else form is safe to
2584 convert. But even in that case we would need to restore any notes
2585 (such as REG_INC) at then end. That can be tricky if
2586 noce_emit_move_insn expands to more than one insn, so disable the
2587 optimization entirely for now if there are side effects. */
2588 if (side_effects_p (x
))
2591 b
= (set_b
? SET_SRC (set_b
) : x
);
2593 /* Only operate on register destinations, and even then avoid extending
2594 the lifetime of hard registers on small register class machines. */
2597 || (HARD_REGISTER_P (x
)
2598 && targetm
.small_register_classes_for_mode_p (GET_MODE (x
))))
2600 if (GET_MODE (x
) == BLKmode
)
2603 if (GET_CODE (x
) == ZERO_EXTRACT
2604 && (!CONST_INT_P (XEXP (x
, 1))
2605 || !CONST_INT_P (XEXP (x
, 2))))
2608 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2609 ? XEXP (x
, 0) : x
));
2612 /* Don't operate on sources that may trap or are volatile. */
2613 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2617 /* Set up the info block for our subroutines. */
2618 if_info
->insn_a
= insn_a
;
2619 if_info
->insn_b
= insn_b
;
2624 /* Try optimizations in some approximation of a useful order. */
2625 /* ??? Should first look to see if X is live incoming at all. If it
2626 isn't, we don't need anything but an unconditional set. */
2628 /* Look and see if A and B are really the same. Avoid creating silly
2629 cmove constructs that no one will fix up later. */
2630 if (rtx_interchangeable_p (a
, b
))
2632 /* If we have an INSN_B, we don't have to create any new rtl. Just
2633 move the instruction that we already have. If we don't have an
2634 INSN_B, that means that A == X, and we've got a noop move. In
2635 that case don't do anything and let the code below delete INSN_A. */
2636 if (insn_b
&& else_bb
)
2640 if (else_bb
&& insn_b
== BB_END (else_bb
))
2641 BB_END (else_bb
) = PREV_INSN (insn_b
);
2642 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2644 /* If there was a REG_EQUAL note, delete it since it may have been
2645 true due to this insn being after a jump. */
2646 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2647 remove_note (insn_b
, note
);
2651 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2652 x must be executed twice. */
2653 else if (insn_b
&& side_effects_p (orig_x
))
2660 if (!set_b
&& MEM_P (orig_x
))
2662 /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
2663 for optimizations if writing to x may trap or fault,
2664 i.e. it's a memory other than a static var or a stack slot,
2665 is misaligned on strict aligned machines or is read-only. If
2666 x is a read-only memory, then the program is valid only if we
2667 avoid the store into it. If there are stores on both the
2668 THEN and ELSE arms, then we can go ahead with the conversion;
2669 either the program is broken, or the condition is always
2670 false such that the other memory is selected. */
2671 if (noce_mem_write_may_trap_or_fault_p (orig_x
))
2674 /* Avoid store speculation: given "if (...) x = a" where x is a
2675 MEM, we only want to do the store if x is always set
2676 somewhere in the function. This avoids cases like
2677 if (pthread_mutex_trylock(mutex))
2679 where we only want global_variable to be changed if the mutex
2680 is held. FIXME: This should ideally be expressed directly in
2682 if (!noce_can_store_speculate_p (test_bb
, orig_x
))
2686 if (noce_try_move (if_info
))
2688 if (noce_try_store_flag (if_info
))
2690 if (noce_try_bitop (if_info
))
2692 if (noce_try_minmax (if_info
))
2694 if (noce_try_abs (if_info
))
2696 if (HAVE_conditional_move
2697 && noce_try_cmove (if_info
))
2699 if (! targetm
.have_conditional_execution ())
2701 if (noce_try_store_flag_constants (if_info
))
2703 if (noce_try_addcc (if_info
))
2705 if (noce_try_store_flag_mask (if_info
))
2707 if (HAVE_conditional_move
2708 && noce_try_cmove_arith (if_info
))
2710 if (noce_try_sign_mask (if_info
))
2714 if (!else_bb
&& set_b
)
2726 /* If we used a temporary, fix it up now. */
2732 noce_emit_move_insn (orig_x
, x
);
2734 set_used_flags (orig_x
);
2735 unshare_all_rtl_in_chain (seq
);
2738 emit_insn_before_setloc (seq
, BB_END (test_bb
), INSN_LOCATION (insn_a
));
2741 /* The original THEN and ELSE blocks may now be removed. The test block
2742 must now jump to the join block. If the test block and the join block
2743 can be merged, do so. */
2746 delete_basic_block (else_bb
);
2750 remove_edge (find_edge (test_bb
, join_bb
));
2752 remove_edge (find_edge (then_bb
, join_bb
));
2753 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2754 delete_basic_block (then_bb
);
2757 if (can_merge_blocks_p (test_bb
, join_bb
))
2759 merge_blocks (test_bb
, join_bb
);
2763 num_updated_if_blocks
++;
2767 /* Check whether a block is suitable for conditional move conversion.
2768 Every insn must be a simple set of a register to a constant or a
2769 register. For each assignment, store the value in the pointer map
2770 VALS, keyed indexed by register pointer, then store the register
2771 pointer in REGS. COND is the condition we will test. */
2774 check_cond_move_block (basic_block bb
,
2775 hash_map
<rtx
, rtx
> *vals
,
2781 /* We can only handle simple jumps at the end of the basic block.
2782 It is almost impossible to update the CFG otherwise. */
2784 if (JUMP_P (insn
) && !onlyjump_p (insn
))
2787 FOR_BB_INSNS (bb
, insn
)
2791 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2793 set
= single_set (insn
);
2797 dest
= SET_DEST (set
);
2798 src
= SET_SRC (set
);
2800 || (HARD_REGISTER_P (dest
)
2801 && targetm
.small_register_classes_for_mode_p (GET_MODE (dest
))))
2804 if (!CONSTANT_P (src
) && !register_operand (src
, VOIDmode
))
2807 if (side_effects_p (src
) || side_effects_p (dest
))
2810 if (may_trap_p (src
) || may_trap_p (dest
))
2813 /* Don't try to handle this if the source register was
2814 modified earlier in the block. */
2817 || (GET_CODE (src
) == SUBREG
&& REG_P (SUBREG_REG (src
))
2818 && vals
->get (SUBREG_REG (src
))))
2821 /* Don't try to handle this if the destination register was
2822 modified earlier in the block. */
2823 if (vals
->get (dest
))
2826 /* Don't try to handle this if the condition uses the
2827 destination register. */
2828 if (reg_overlap_mentioned_p (dest
, cond
))
2831 /* Don't try to handle this if the source register is modified
2832 later in the block. */
2833 if (!CONSTANT_P (src
)
2834 && modified_between_p (src
, insn
, NEXT_INSN (BB_END (bb
))))
2837 vals
->put (dest
, src
);
2839 regs
->safe_push (dest
);
2845 /* Given a basic block BB suitable for conditional move conversion,
2846 a condition COND, and pointer maps THEN_VALS and ELSE_VALS containing
2847 the register values depending on COND, emit the insns in the block as
2848 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2849 processed. The caller has started a sequence for the conversion.
2850 Return true if successful, false if something goes wrong. */
2853 cond_move_convert_if_block (struct noce_if_info
*if_infop
,
2854 basic_block bb
, rtx cond
,
2855 hash_map
<rtx
, rtx
> *then_vals
,
2856 hash_map
<rtx
, rtx
> *else_vals
,
2861 rtx cond_arg0
, cond_arg1
;
2863 code
= GET_CODE (cond
);
2864 cond_arg0
= XEXP (cond
, 0);
2865 cond_arg1
= XEXP (cond
, 1);
2867 FOR_BB_INSNS (bb
, insn
)
2869 rtx set
, target
, dest
, t
, e
;
2871 /* ??? Maybe emit conditional debug insn? */
2872 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2874 set
= single_set (insn
);
2875 gcc_assert (set
&& REG_P (SET_DEST (set
)));
2877 dest
= SET_DEST (set
);
2879 rtx
*then_slot
= then_vals
->get (dest
);
2880 rtx
*else_slot
= else_vals
->get (dest
);
2881 t
= then_slot
? *then_slot
: NULL_RTX
;
2882 e
= else_slot
? *else_slot
: NULL_RTX
;
2886 /* If this register was set in the then block, we already
2887 handled this case there. */
2900 target
= noce_emit_cmove (if_infop
, dest
, code
, cond_arg0
, cond_arg1
,
2906 noce_emit_move_insn (dest
, target
);
2912 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2913 it using only conditional moves. Return TRUE if we were successful at
2914 converting the block. */
2917 cond_move_process_if_block (struct noce_if_info
*if_info
)
2919 basic_block test_bb
= if_info
->test_bb
;
2920 basic_block then_bb
= if_info
->then_bb
;
2921 basic_block else_bb
= if_info
->else_bb
;
2922 basic_block join_bb
= if_info
->join_bb
;
2923 rtx_insn
*jump
= if_info
->jump
;
2924 rtx cond
= if_info
->cond
;
2925 rtx_insn
*seq
, *loc_insn
;
2928 vec
<rtx
> then_regs
= vNULL
;
2929 vec
<rtx
> else_regs
= vNULL
;
2931 int success_p
= FALSE
;
2933 /* Build a mapping for each block to the value used for each
2935 hash_map
<rtx
, rtx
> then_vals
;
2936 hash_map
<rtx
, rtx
> else_vals
;
2938 /* Make sure the blocks are suitable. */
2939 if (!check_cond_move_block (then_bb
, &then_vals
, &then_regs
, cond
)
2941 && !check_cond_move_block (else_bb
, &else_vals
, &else_regs
, cond
)))
2944 /* Make sure the blocks can be used together. If the same register
2945 is set in both blocks, and is not set to a constant in both
2946 cases, then both blocks must set it to the same register. We
2947 have already verified that if it is set to a register, that the
2948 source register does not change after the assignment. Also count
2949 the number of registers set in only one of the blocks. */
2951 FOR_EACH_VEC_ELT (then_regs
, i
, reg
)
2953 rtx
*then_slot
= then_vals
.get (reg
);
2954 rtx
*else_slot
= else_vals
.get (reg
);
2956 gcc_checking_assert (then_slot
);
2961 rtx then_val
= *then_slot
;
2962 rtx else_val
= *else_slot
;
2963 if (!CONSTANT_P (then_val
) && !CONSTANT_P (else_val
)
2964 && !rtx_equal_p (then_val
, else_val
))
2969 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
2970 FOR_EACH_VEC_ELT (else_regs
, i
, reg
)
2972 gcc_checking_assert (else_vals
.get (reg
));
2973 if (!then_vals
.get (reg
))
2977 /* Make sure it is reasonable to convert this block. What matters
2978 is the number of assignments currently made in only one of the
2979 branches, since if we convert we are going to always execute
2981 if (c
> MAX_CONDITIONAL_EXECUTE
)
2984 /* Try to emit the conditional moves. First do the then block,
2985 then do anything left in the else blocks. */
2987 if (!cond_move_convert_if_block (if_info
, then_bb
, cond
,
2988 &then_vals
, &else_vals
, false)
2990 && !cond_move_convert_if_block (if_info
, else_bb
, cond
,
2991 &then_vals
, &else_vals
, true)))
2996 seq
= end_ifcvt_sequence (if_info
);
3000 loc_insn
= first_active_insn (then_bb
);
3003 loc_insn
= first_active_insn (else_bb
);
3004 gcc_assert (loc_insn
);
3006 emit_insn_before_setloc (seq
, jump
, INSN_LOCATION (loc_insn
));
3010 delete_basic_block (else_bb
);
3014 remove_edge (find_edge (test_bb
, join_bb
));
3016 remove_edge (find_edge (then_bb
, join_bb
));
3017 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
3018 delete_basic_block (then_bb
);
3021 if (can_merge_blocks_p (test_bb
, join_bb
))
3023 merge_blocks (test_bb
, join_bb
);
3027 num_updated_if_blocks
++;
3032 then_regs
.release ();
3033 else_regs
.release ();
3038 /* Determine if a given basic block heads a simple IF-THEN-JOIN or an
3039 IF-THEN-ELSE-JOIN block.
3041 If so, we'll try to convert the insns to not require the branch,
3042 using only transformations that do not require conditional execution.
3044 Return TRUE if we were successful at converting the block. */
3047 noce_find_if_block (basic_block test_bb
, edge then_edge
, edge else_edge
,
3050 basic_block then_bb
, else_bb
, join_bb
;
3051 bool then_else_reversed
= false;
3054 rtx_insn
*cond_earliest
;
3055 struct noce_if_info if_info
;
3057 /* We only ever should get here before reload. */
3058 gcc_assert (!reload_completed
);
3060 /* Recognize an IF-THEN-ELSE-JOIN block. */
3061 if (single_pred_p (then_edge
->dest
)
3062 && single_succ_p (then_edge
->dest
)
3063 && single_pred_p (else_edge
->dest
)
3064 && single_succ_p (else_edge
->dest
)
3065 && single_succ (then_edge
->dest
) == single_succ (else_edge
->dest
))
3067 then_bb
= then_edge
->dest
;
3068 else_bb
= else_edge
->dest
;
3069 join_bb
= single_succ (then_bb
);
3071 /* Recognize an IF-THEN-JOIN block. */
3072 else if (single_pred_p (then_edge
->dest
)
3073 && single_succ_p (then_edge
->dest
)
3074 && single_succ (then_edge
->dest
) == else_edge
->dest
)
3076 then_bb
= then_edge
->dest
;
3077 else_bb
= NULL_BLOCK
;
3078 join_bb
= else_edge
->dest
;
3080 /* Recognize an IF-ELSE-JOIN block. We can have those because the order
3081 of basic blocks in cfglayout mode does not matter, so the fallthrough
3082 edge can go to any basic block (and not just to bb->next_bb, like in
3084 else if (single_pred_p (else_edge
->dest
)
3085 && single_succ_p (else_edge
->dest
)
3086 && single_succ (else_edge
->dest
) == then_edge
->dest
)
3088 /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
3089 To make this work, we have to invert the THEN and ELSE blocks
3090 and reverse the jump condition. */
3091 then_bb
= else_edge
->dest
;
3092 else_bb
= NULL_BLOCK
;
3093 join_bb
= single_succ (then_bb
);
3094 then_else_reversed
= true;
3097 /* Not a form we can handle. */
3100 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3101 if (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3104 && single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3107 num_possible_if_blocks
++;
3112 "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
3113 (else_bb
) ? "-ELSE" : "",
3114 pass
, test_bb
->index
, then_bb
->index
);
3117 fprintf (dump_file
, ", else %d", else_bb
->index
);
3119 fprintf (dump_file
, ", join %d\n", join_bb
->index
);
3122 /* If the conditional jump is more than just a conditional
3123 jump, then we can not do if-conversion on this block. */
3124 jump
= BB_END (test_bb
);
3125 if (! onlyjump_p (jump
))
3128 /* If this is not a standard conditional jump, we can't parse it. */
3129 cond
= noce_get_condition (jump
, &cond_earliest
, then_else_reversed
);
3133 /* We must be comparing objects whose modes imply the size. */
3134 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3137 /* Initialize an IF_INFO struct to pass around. */
3138 memset (&if_info
, 0, sizeof if_info
);
3139 if_info
.test_bb
= test_bb
;
3140 if_info
.then_bb
= then_bb
;
3141 if_info
.else_bb
= else_bb
;
3142 if_info
.join_bb
= join_bb
;
3143 if_info
.cond
= cond
;
3144 if_info
.cond_earliest
= cond_earliest
;
3145 if_info
.jump
= jump
;
3146 if_info
.then_else_reversed
= then_else_reversed
;
3147 if_info
.branch_cost
= BRANCH_COST (optimize_bb_for_speed_p (test_bb
),
3148 predictable_edge_p (then_edge
));
3150 /* Do the real work. */
3152 if (noce_process_if_block (&if_info
))
3155 if (HAVE_conditional_move
3156 && cond_move_process_if_block (&if_info
))
3163 /* Merge the blocks and mark for local life update. */
3166 merge_if_block (struct ce_if_block
* ce_info
)
3168 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
3169 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
3170 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
3171 basic_block join_bb
= ce_info
->join_bb
; /* join block */
3172 basic_block combo_bb
;
3174 /* All block merging is done into the lower block numbers. */
3177 df_set_bb_dirty (test_bb
);
3179 /* Merge any basic blocks to handle && and || subtests. Each of
3180 the blocks are on the fallthru path from the predecessor block. */
3181 if (ce_info
->num_multiple_test_blocks
> 0)
3183 basic_block bb
= test_bb
;
3184 basic_block last_test_bb
= ce_info
->last_test_bb
;
3185 basic_block fallthru
= block_fallthru (bb
);
3190 fallthru
= block_fallthru (bb
);
3191 merge_blocks (combo_bb
, bb
);
3194 while (bb
!= last_test_bb
);
3197 /* Merge TEST block into THEN block. Normally the THEN block won't have a
3198 label, but it might if there were || tests. That label's count should be
3199 zero, and it normally should be removed. */
3203 /* If THEN_BB has no successors, then there's a BARRIER after it.
3204 If COMBO_BB has more than one successor (THEN_BB), then that BARRIER
3205 is no longer needed, and in fact it is incorrect to leave it in
3207 if (EDGE_COUNT (then_bb
->succs
) == 0
3208 && EDGE_COUNT (combo_bb
->succs
) > 1)
3210 rtx_insn
*end
= NEXT_INSN (BB_END (then_bb
));
3211 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3212 end
= NEXT_INSN (end
);
3214 if (end
&& BARRIER_P (end
))
3217 merge_blocks (combo_bb
, then_bb
);
3221 /* The ELSE block, if it existed, had a label. That label count
3222 will almost always be zero, but odd things can happen when labels
3223 get their addresses taken. */
3226 /* If ELSE_BB has no successors, then there's a BARRIER after it.
3227 If COMBO_BB has more than one successor (ELSE_BB), then that BARRIER
3228 is no longer needed, and in fact it is incorrect to leave it in
3230 if (EDGE_COUNT (else_bb
->succs
) == 0
3231 && EDGE_COUNT (combo_bb
->succs
) > 1)
3233 rtx_insn
*end
= NEXT_INSN (BB_END (else_bb
));
3234 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3235 end
= NEXT_INSN (end
);
3237 if (end
&& BARRIER_P (end
))
3240 merge_blocks (combo_bb
, else_bb
);
3244 /* If there was no join block reported, that means it was not adjacent
3245 to the others, and so we cannot merge them. */
3249 rtx_insn
*last
= BB_END (combo_bb
);
3251 /* The outgoing edge for the current COMBO block should already
3252 be correct. Verify this. */
3253 if (EDGE_COUNT (combo_bb
->succs
) == 0)
3254 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
3255 || (NONJUMP_INSN_P (last
)
3256 && GET_CODE (PATTERN (last
)) == TRAP_IF
3257 && (TRAP_CONDITION (PATTERN (last
))
3258 == const_true_rtx
)));
3261 /* There should still be something at the end of the THEN or ELSE
3262 blocks taking us to our final destination. */
3263 gcc_assert (JUMP_P (last
)
3264 || (EDGE_SUCC (combo_bb
, 0)->dest
3265 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3267 && SIBLING_CALL_P (last
))
3268 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
3269 && can_throw_internal (last
)));
3272 /* The JOIN block may have had quite a number of other predecessors too.
3273 Since we've already merged the TEST, THEN and ELSE blocks, we should
3274 have only one remaining edge from our if-then-else diamond. If there
3275 is more than one remaining edge, it must come from elsewhere. There
3276 may be zero incoming edges if the THEN block didn't actually join
3277 back up (as with a call to a non-return function). */
3278 else if (EDGE_COUNT (join_bb
->preds
) < 2
3279 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3281 /* We can merge the JOIN cleanly and update the dataflow try
3282 again on this pass.*/
3283 merge_blocks (combo_bb
, join_bb
);
3288 /* We cannot merge the JOIN. */
3290 /* The outgoing edge for the current COMBO block should already
3291 be correct. Verify this. */
3292 gcc_assert (single_succ_p (combo_bb
)
3293 && single_succ (combo_bb
) == join_bb
);
3295 /* Remove the jump and cruft from the end of the COMBO block. */
3296 if (join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3297 tidy_fallthru_edge (single_succ_edge (combo_bb
));
3300 num_updated_if_blocks
++;
3303 /* Find a block ending in a simple IF condition and try to transform it
3304 in some way. When converting a multi-block condition, put the new code
3305 in the first such block and delete the rest. Return a pointer to this
3306 first block if some transformation was done. Return NULL otherwise. */
3309 find_if_header (basic_block test_bb
, int pass
)
3311 ce_if_block ce_info
;
3315 /* The kind of block we're looking for has exactly two successors. */
3316 if (EDGE_COUNT (test_bb
->succs
) != 2)
3319 then_edge
= EDGE_SUCC (test_bb
, 0);
3320 else_edge
= EDGE_SUCC (test_bb
, 1);
3322 if (df_get_bb_dirty (then_edge
->dest
))
3324 if (df_get_bb_dirty (else_edge
->dest
))
3327 /* Neither edge should be abnormal. */
3328 if ((then_edge
->flags
& EDGE_COMPLEX
)
3329 || (else_edge
->flags
& EDGE_COMPLEX
))
3332 /* Nor exit the loop. */
3333 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
3334 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
3337 /* The THEN edge is canonically the one that falls through. */
3338 if (then_edge
->flags
& EDGE_FALLTHRU
)
3340 else if (else_edge
->flags
& EDGE_FALLTHRU
)
3343 else_edge
= then_edge
;
3347 /* Otherwise this must be a multiway branch of some sort. */
3350 memset (&ce_info
, 0, sizeof (ce_info
));
3351 ce_info
.test_bb
= test_bb
;
3352 ce_info
.then_bb
= then_edge
->dest
;
3353 ce_info
.else_bb
= else_edge
->dest
;
3354 ce_info
.pass
= pass
;
3356 #ifdef IFCVT_MACHDEP_INIT
3357 IFCVT_MACHDEP_INIT (&ce_info
);
3360 if (!reload_completed
3361 && noce_find_if_block (test_bb
, then_edge
, else_edge
, pass
))
3364 if (reload_completed
3365 && targetm
.have_conditional_execution ()
3366 && cond_exec_find_if_block (&ce_info
))
3370 && optab_handler (ctrap_optab
, word_mode
) != CODE_FOR_nothing
3371 && find_cond_trap (test_bb
, then_edge
, else_edge
))
3374 if (dom_info_state (CDI_POST_DOMINATORS
) >= DOM_NO_FAST_QUERY
3375 && (reload_completed
|| !targetm
.have_conditional_execution ()))
3377 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
3379 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
3387 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
3388 /* Set this so we continue looking. */
3389 cond_exec_changed_p
= TRUE
;
3390 return ce_info
.test_bb
;
3393 /* Return true if a block has two edges, one of which falls through to the next
3394 block, and the other jumps to a specific block, so that we can tell if the
3395 block is part of an && test or an || test. Returns either -1 or the number
3396 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
3399 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
3402 int fallthru_p
= FALSE
;
3409 if (!cur_bb
|| !target_bb
)
3412 /* If no edges, obviously it doesn't jump or fallthru. */
3413 if (EDGE_COUNT (cur_bb
->succs
) == 0)
3416 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
3418 if (cur_edge
->flags
& EDGE_COMPLEX
)
3419 /* Anything complex isn't what we want. */
3422 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
3425 else if (cur_edge
->dest
== target_bb
)
3432 if ((jump_p
& fallthru_p
) == 0)
3435 /* Don't allow calls in the block, since this is used to group && and ||
3436 together for conditional execution support. ??? we should support
3437 conditional execution support across calls for IA-64 some day, but
3438 for now it makes the code simpler. */
3439 end
= BB_END (cur_bb
);
3440 insn
= BB_HEAD (cur_bb
);
3442 while (insn
!= NULL_RTX
)
3449 && !DEBUG_INSN_P (insn
)
3450 && GET_CODE (PATTERN (insn
)) != USE
3451 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
3457 insn
= NEXT_INSN (insn
);
3463 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3464 block. If so, we'll try to convert the insns to not require the branch.
3465 Return TRUE if we were successful at converting the block. */
3468 cond_exec_find_if_block (struct ce_if_block
* ce_info
)
3470 basic_block test_bb
= ce_info
->test_bb
;
3471 basic_block then_bb
= ce_info
->then_bb
;
3472 basic_block else_bb
= ce_info
->else_bb
;
3473 basic_block join_bb
= NULL_BLOCK
;
3478 ce_info
->last_test_bb
= test_bb
;
3480 /* We only ever should get here after reload,
3481 and if we have conditional execution. */
3482 gcc_assert (reload_completed
&& targetm
.have_conditional_execution ());
3484 /* Discover if any fall through predecessors of the current test basic block
3485 were && tests (which jump to the else block) or || tests (which jump to
3487 if (single_pred_p (test_bb
)
3488 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
3490 basic_block bb
= single_pred (test_bb
);
3491 basic_block target_bb
;
3492 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
3495 /* Determine if the preceding block is an && or || block. */
3496 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
3498 ce_info
->and_and_p
= TRUE
;
3499 target_bb
= else_bb
;
3501 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
3503 ce_info
->and_and_p
= FALSE
;
3504 target_bb
= then_bb
;
3507 target_bb
= NULL_BLOCK
;
3509 if (target_bb
&& n_insns
<= max_insns
)
3511 int total_insns
= 0;
3514 ce_info
->last_test_bb
= test_bb
;
3516 /* Found at least one && or || block, look for more. */
3519 ce_info
->test_bb
= test_bb
= bb
;
3520 total_insns
+= n_insns
;
3523 if (!single_pred_p (bb
))
3526 bb
= single_pred (bb
);
3527 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
3529 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
3531 ce_info
->num_multiple_test_blocks
= blocks
;
3532 ce_info
->num_multiple_test_insns
= total_insns
;
3534 if (ce_info
->and_and_p
)
3535 ce_info
->num_and_and_blocks
= blocks
;
3537 ce_info
->num_or_or_blocks
= blocks
;
3541 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3542 other than any || blocks which jump to the THEN block. */
3543 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
3546 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3547 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
3549 if (cur_edge
->flags
& EDGE_COMPLEX
)
3553 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
3555 if (cur_edge
->flags
& EDGE_COMPLEX
)
3559 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3560 if (EDGE_COUNT (then_bb
->succs
) > 0
3561 && (!single_succ_p (then_bb
)
3562 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3563 || (epilogue_completed
3564 && tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
3567 /* If the THEN block has no successors, conditional execution can still
3568 make a conditional call. Don't do this unless the ELSE block has
3569 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3570 Check for the last insn of the THEN block being an indirect jump, which
3571 is listed as not having any successors, but confuses the rest of the CE
3572 code processing. ??? we should fix this in the future. */
3573 if (EDGE_COUNT (then_bb
->succs
) == 0)
3575 if (single_pred_p (else_bb
) && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3577 rtx_insn
*last_insn
= BB_END (then_bb
);
3580 && NOTE_P (last_insn
)
3581 && last_insn
!= BB_HEAD (then_bb
))
3582 last_insn
= PREV_INSN (last_insn
);
3585 && JUMP_P (last_insn
)
3586 && ! simplejump_p (last_insn
))
3590 else_bb
= NULL_BLOCK
;
3596 /* If the THEN block's successor is the other edge out of the TEST block,
3597 then we have an IF-THEN combo without an ELSE. */
3598 else if (single_succ (then_bb
) == else_bb
)
3601 else_bb
= NULL_BLOCK
;
3604 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3605 has exactly one predecessor and one successor, and the outgoing edge
3606 is not complex, then we have an IF-THEN-ELSE combo. */
3607 else if (single_succ_p (else_bb
)
3608 && single_succ (then_bb
) == single_succ (else_bb
)
3609 && single_pred_p (else_bb
)
3610 && !(single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3611 && !(epilogue_completed
3612 && tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
3613 join_bb
= single_succ (else_bb
);
3615 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3619 num_possible_if_blocks
++;
3624 "\nIF-THEN%s block found, pass %d, start block %d "
3625 "[insn %d], then %d [%d]",
3626 (else_bb
) ? "-ELSE" : "",
3629 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
3631 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
3634 fprintf (dump_file
, ", else %d [%d]",
3636 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
3638 fprintf (dump_file
, ", join %d [%d]",
3640 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
3642 if (ce_info
->num_multiple_test_blocks
> 0)
3643 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
3644 ce_info
->num_multiple_test_blocks
,
3645 (ce_info
->and_and_p
) ? "&&" : "||",
3646 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
3647 ce_info
->last_test_bb
->index
,
3648 ((BB_HEAD (ce_info
->last_test_bb
))
3649 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
3652 fputc ('\n', dump_file
);
3655 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3656 first condition for free, since we've already asserted that there's a
3657 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3658 we checked the FALLTHRU flag, those are already adjacent to the last IF
3660 /* ??? As an enhancement, move the ELSE block. Have to deal with
3661 BLOCK notes, if by no other means than backing out the merge if they
3662 exist. Sticky enough I don't want to think about it now. */
3664 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
3666 if ((next
= next
->next_bb
) != join_bb
3667 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3675 /* Do the real work. */
3677 ce_info
->else_bb
= else_bb
;
3678 ce_info
->join_bb
= join_bb
;
3680 /* If we have && and || tests, try to first handle combining the && and ||
3681 tests into the conditional code, and if that fails, go back and handle
3682 it without the && and ||, which at present handles the && case if there
3683 was no ELSE block. */
3684 if (cond_exec_process_if_block (ce_info
, TRUE
))
3687 if (ce_info
->num_multiple_test_blocks
)
3691 if (cond_exec_process_if_block (ce_info
, FALSE
))
3698 /* Convert a branch over a trap, or a branch
3699 to a trap, into a conditional trap. */
3702 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
3704 basic_block then_bb
= then_edge
->dest
;
3705 basic_block else_bb
= else_edge
->dest
;
3706 basic_block other_bb
, trap_bb
;
3707 rtx_insn
*trap
, *jump
;
3709 rtx_insn
*cond_earliest
;
3712 /* Locate the block with the trap instruction. */
3713 /* ??? While we look for no successors, we really ought to allow
3714 EH successors. Need to fix merge_if_block for that to work. */
3715 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
3716 trap_bb
= then_bb
, other_bb
= else_bb
;
3717 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
3718 trap_bb
= else_bb
, other_bb
= then_bb
;
3724 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
3725 test_bb
->index
, trap_bb
->index
);
3728 /* If this is not a standard conditional jump, we can't parse it. */
3729 jump
= BB_END (test_bb
);
3730 cond
= noce_get_condition (jump
, &cond_earliest
, false);
3734 /* If the conditional jump is more than just a conditional jump, then
3735 we can not do if-conversion on this block. */
3736 if (! onlyjump_p (jump
))
3739 /* We must be comparing objects whose modes imply the size. */
3740 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3743 /* Reverse the comparison code, if necessary. */
3744 code
= GET_CODE (cond
);
3745 if (then_bb
== trap_bb
)
3747 code
= reversed_comparison_code (cond
, jump
);
3748 if (code
== UNKNOWN
)
3752 /* Attempt to generate the conditional trap. */
3753 seq
= gen_cond_trap (code
, copy_rtx (XEXP (cond
, 0)),
3754 copy_rtx (XEXP (cond
, 1)),
3755 TRAP_CODE (PATTERN (trap
)));
3759 /* Emit the new insns before cond_earliest. */
3760 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATION (trap
));
3762 /* Delete the trap block if possible. */
3763 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
3764 df_set_bb_dirty (test_bb
);
3765 df_set_bb_dirty (then_bb
);
3766 df_set_bb_dirty (else_bb
);
3768 if (EDGE_COUNT (trap_bb
->preds
) == 0)
3770 delete_basic_block (trap_bb
);
3774 /* Wire together the blocks again. */
3775 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
3776 single_succ_edge (test_bb
)->flags
|= EDGE_FALLTHRU
;
3777 else if (trap_bb
== then_bb
)
3782 lab
= JUMP_LABEL (jump
);
3783 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
3784 LABEL_NUSES (lab
) += 1;
3785 JUMP_LABEL (newjump
) = lab
;
3786 emit_barrier_after (newjump
);
3790 if (can_merge_blocks_p (test_bb
, other_bb
))
3792 merge_blocks (test_bb
, other_bb
);
3796 num_updated_if_blocks
++;
3800 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3804 block_has_only_trap (basic_block bb
)
3808 /* We're not the exit block. */
3809 if (bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3812 /* The block must have no successors. */
3813 if (EDGE_COUNT (bb
->succs
) > 0)
3816 /* The only instruction in the THEN block must be the trap. */
3817 trap
= first_active_insn (bb
);
3818 if (! (trap
== BB_END (bb
)
3819 && GET_CODE (PATTERN (trap
)) == TRAP_IF
3820 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
3826 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3827 transformable, but not necessarily the other. There need be no
3830 Return TRUE if we were successful at converting the block.
3832 Cases we'd like to look at:
3835 if (test) goto over; // x not live
3843 if (! test) goto label;
3846 if (test) goto E; // x not live
3860 (3) // This one's really only interesting for targets that can do
3861 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3862 // it results in multiple branches on a cache line, which often
3863 // does not sit well with predictors.
3865 if (test1) goto E; // predicted not taken
3881 (A) Don't do (2) if the branch is predicted against the block we're
3882 eliminating. Do it anyway if we can eliminate a branch; this requires
3883 that the sole successor of the eliminated block postdominate the other
3886 (B) With CE, on (3) we can steal from both sides of the if, creating
3895 Again, this is most useful if J postdominates.
3897 (C) CE substitutes for helpful life information.
3899 (D) These heuristics need a lot of work. */
3901 /* Tests for case 1 above. */
3904 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3906 basic_block then_bb
= then_edge
->dest
;
3907 basic_block else_bb
= else_edge
->dest
;
3909 int then_bb_index
, then_prob
;
3910 rtx else_target
= NULL_RTX
;
3912 /* If we are partitioning hot/cold basic blocks, we don't want to
3913 mess up unconditional or indirect jumps that cross between hot
3916 Basic block partitioning may result in some jumps that appear to
3917 be optimizable (or blocks that appear to be mergeable), but which really
3918 must be left untouched (they are required to make it safely across
3919 partition boundaries). See the comments at the top of
3920 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3922 if ((BB_END (then_bb
)
3923 && JUMP_P (BB_END (then_bb
))
3924 && CROSSING_JUMP_P (BB_END (then_bb
)))
3925 || (BB_END (test_bb
)
3926 && JUMP_P (BB_END (test_bb
))
3927 && CROSSING_JUMP_P (BB_END (test_bb
)))
3928 || (BB_END (else_bb
)
3929 && JUMP_P (BB_END (else_bb
))
3930 && CROSSING_JUMP_P (BB_END (else_bb
))))
3933 /* THEN has one successor. */
3934 if (!single_succ_p (then_bb
))
3937 /* THEN does not fall through, but is not strange either. */
3938 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
3941 /* THEN has one predecessor. */
3942 if (!single_pred_p (then_bb
))
3945 /* THEN must do something. */
3946 if (forwarder_block_p (then_bb
))
3949 num_possible_if_blocks
++;
3952 "\nIF-CASE-1 found, start %d, then %d\n",
3953 test_bb
->index
, then_bb
->index
);
3955 if (then_edge
->probability
)
3956 then_prob
= REG_BR_PROB_BASE
- then_edge
->probability
;
3958 then_prob
= REG_BR_PROB_BASE
/ 2;
3960 /* We're speculating from the THEN path, we want to make sure the cost
3961 of speculation is within reason. */
3962 if (! cheap_bb_rtx_cost_p (then_bb
, then_prob
,
3963 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge
->src
),
3964 predictable_edge_p (then_edge
)))))
3967 if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3969 rtx_insn
*jump
= BB_END (else_edge
->src
);
3970 gcc_assert (JUMP_P (jump
));
3971 else_target
= JUMP_LABEL (jump
);
3974 /* Registers set are dead, or are predicable. */
3975 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
3976 single_succ_edge (then_bb
), 1))
3979 /* Conversion went ok, including moving the insns and fixing up the
3980 jump. Adjust the CFG to match. */
3982 /* We can avoid creating a new basic block if then_bb is immediately
3983 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3984 through to else_bb. */
3986 if (then_bb
->next_bb
== else_bb
3987 && then_bb
->prev_bb
== test_bb
3988 && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3990 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
3993 else if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3994 new_bb
= force_nonfallthru_and_redirect (FALLTHRU_EDGE (test_bb
),
3995 else_bb
, else_target
);
3997 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
4000 df_set_bb_dirty (test_bb
);
4001 df_set_bb_dirty (else_bb
);
4003 then_bb_index
= then_bb
->index
;
4004 delete_basic_block (then_bb
);
4006 /* Make rest of code believe that the newly created block is the THEN_BB
4007 block we removed. */
4010 df_bb_replace (then_bb_index
, new_bb
);
4011 /* This should have been done above via force_nonfallthru_and_redirect
4012 (possibly called from redirect_edge_and_branch_force). */
4013 gcc_checking_assert (BB_PARTITION (new_bb
) == BB_PARTITION (test_bb
));
4017 num_updated_if_blocks
++;
4022 /* Test for case 2 above. */
4025 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
4027 basic_block then_bb
= then_edge
->dest
;
4028 basic_block else_bb
= else_edge
->dest
;
4030 int then_prob
, else_prob
;
4032 /* We do not want to speculate (empty) loop latches. */
4034 && else_bb
->loop_father
->latch
== else_bb
)
4037 /* If we are partitioning hot/cold basic blocks, we don't want to
4038 mess up unconditional or indirect jumps that cross between hot
4041 Basic block partitioning may result in some jumps that appear to
4042 be optimizable (or blocks that appear to be mergeable), but which really
4043 must be left untouched (they are required to make it safely across
4044 partition boundaries). See the comments at the top of
4045 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4047 if ((BB_END (then_bb
)
4048 && JUMP_P (BB_END (then_bb
))
4049 && CROSSING_JUMP_P (BB_END (then_bb
)))
4050 || (BB_END (test_bb
)
4051 && JUMP_P (BB_END (test_bb
))
4052 && CROSSING_JUMP_P (BB_END (test_bb
)))
4053 || (BB_END (else_bb
)
4054 && JUMP_P (BB_END (else_bb
))
4055 && CROSSING_JUMP_P (BB_END (else_bb
))))
4058 /* ELSE has one successor. */
4059 if (!single_succ_p (else_bb
))
4062 else_succ
= single_succ_edge (else_bb
);
4064 /* ELSE outgoing edge is not complex. */
4065 if (else_succ
->flags
& EDGE_COMPLEX
)
4068 /* ELSE has one predecessor. */
4069 if (!single_pred_p (else_bb
))
4072 /* THEN is not EXIT. */
4073 if (then_bb
->index
< NUM_FIXED_BLOCKS
)
4076 if (else_edge
->probability
)
4078 else_prob
= else_edge
->probability
;
4079 then_prob
= REG_BR_PROB_BASE
- else_prob
;
4083 else_prob
= REG_BR_PROB_BASE
/ 2;
4084 then_prob
= REG_BR_PROB_BASE
/ 2;
4087 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
4088 if (else_prob
> then_prob
)
4090 else if (else_succ
->dest
->index
< NUM_FIXED_BLOCKS
4091 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
4097 num_possible_if_blocks
++;
4100 "\nIF-CASE-2 found, start %d, else %d\n",
4101 test_bb
->index
, else_bb
->index
);
4103 /* We're speculating from the ELSE path, we want to make sure the cost
4104 of speculation is within reason. */
4105 if (! cheap_bb_rtx_cost_p (else_bb
, else_prob
,
4106 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge
->src
),
4107 predictable_edge_p (else_edge
)))))
4110 /* Registers set are dead, or are predicable. */
4111 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
, 0))
4114 /* Conversion went ok, including moving the insns and fixing up the
4115 jump. Adjust the CFG to match. */
4117 df_set_bb_dirty (test_bb
);
4118 df_set_bb_dirty (then_bb
);
4119 delete_basic_block (else_bb
);
4122 num_updated_if_blocks
++;
4124 /* ??? We may now fallthru from one of THEN's successors into a join
4125 block. Rerun cleanup_cfg? Examine things manually? Wait? */
4130 /* Used by the code above to perform the actual rtl transformations.
4131 Return TRUE if successful.
4133 TEST_BB is the block containing the conditional branch. MERGE_BB
4134 is the block containing the code to manipulate. DEST_EDGE is an
4135 edge representing a jump to the join block; after the conversion,
4136 TEST_BB should be branching to its destination.
4137 REVERSEP is true if the sense of the branch should be reversed. */
4140 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
4141 basic_block other_bb
, edge dest_edge
, int reversep
)
4143 basic_block new_dest
= dest_edge
->dest
;
4144 rtx_insn
*head
, *end
, *jump
;
4145 rtx_insn
*earliest
= NULL
;
4147 bitmap merge_set
= NULL
;
4148 /* Number of pending changes. */
4149 int n_validated_changes
= 0;
4150 rtx new_dest_label
= NULL_RTX
;
4152 jump
= BB_END (test_bb
);
4154 /* Find the extent of the real code in the merge block. */
4155 head
= BB_HEAD (merge_bb
);
4156 end
= BB_END (merge_bb
);
4158 while (DEBUG_INSN_P (end
) && end
!= head
)
4159 end
= PREV_INSN (end
);
4161 /* If merge_bb ends with a tablejump, predicating/moving insn's
4162 into test_bb and then deleting merge_bb will result in the jumptable
4163 that follows merge_bb being removed along with merge_bb and then we
4164 get an unresolved reference to the jumptable. */
4165 if (tablejump_p (end
, NULL
, NULL
))
4169 head
= NEXT_INSN (head
);
4170 while (DEBUG_INSN_P (head
) && head
!= end
)
4171 head
= NEXT_INSN (head
);
4179 head
= NEXT_INSN (head
);
4180 while (DEBUG_INSN_P (head
) && head
!= end
)
4181 head
= NEXT_INSN (head
);
4186 if (!onlyjump_p (end
))
4193 end
= PREV_INSN (end
);
4194 while (DEBUG_INSN_P (end
) && end
!= head
)
4195 end
= PREV_INSN (end
);
4198 /* Don't move frame-related insn across the conditional branch. This
4199 can lead to one of the paths of the branch having wrong unwind info. */
4200 if (epilogue_completed
)
4202 rtx_insn
*insn
= head
;
4205 if (INSN_P (insn
) && RTX_FRAME_RELATED_P (insn
))
4209 insn
= NEXT_INSN (insn
);
4213 /* Disable handling dead code by conditional execution if the machine needs
4214 to do anything funny with the tests, etc. */
4215 #ifndef IFCVT_MODIFY_TESTS
4216 if (targetm
.have_conditional_execution ())
4218 /* In the conditional execution case, we have things easy. We know
4219 the condition is reversible. We don't have to check life info
4220 because we're going to conditionally execute the code anyway.
4221 All that's left is making sure the insns involved can actually
4226 cond
= cond_exec_get_condition (jump
);
4230 rtx note
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
4231 int prob_val
= (note
? XINT (note
, 0) : -1);
4235 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
4238 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
4241 prob_val
= REG_BR_PROB_BASE
- prob_val
;
4244 if (cond_exec_process_insns (NULL
, head
, end
, cond
, prob_val
, 0)
4245 && verify_changes (0))
4246 n_validated_changes
= num_validated_changes ();
4254 /* If we allocated new pseudos (e.g. in the conditional move
4255 expander called from noce_emit_cmove), we must resize the
4257 if (max_regno
< max_reg_num ())
4258 max_regno
= max_reg_num ();
4260 /* Try the NCE path if the CE path did not result in any changes. */
4261 if (n_validated_changes
== 0)
4268 /* In the non-conditional execution case, we have to verify that there
4269 are no trapping operations, no calls, no references to memory, and
4270 that any registers modified are dead at the branch site. */
4272 if (!any_condjump_p (jump
))
4275 /* Find the extent of the conditional. */
4276 cond
= noce_get_condition (jump
, &earliest
, false);
4280 live
= BITMAP_ALLOC (®_obstack
);
4281 simulate_backwards_to_point (merge_bb
, live
, end
);
4282 success
= can_move_insns_across (head
, end
, earliest
, jump
,
4284 df_get_live_in (other_bb
), NULL
);
4289 /* Collect the set of registers set in MERGE_BB. */
4290 merge_set
= BITMAP_ALLOC (®_obstack
);
4292 FOR_BB_INSNS (merge_bb
, insn
)
4293 if (NONDEBUG_INSN_P (insn
))
4294 df_simulate_find_defs (insn
, merge_set
);
4296 /* If shrink-wrapping, disable this optimization when test_bb is
4297 the first basic block and merge_bb exits. The idea is to not
4298 move code setting up a return register as that may clobber a
4299 register used to pass function parameters, which then must be
4300 saved in caller-saved regs. A caller-saved reg requires the
4301 prologue, killing a shrink-wrap opportunity. */
4302 if ((SHRINK_WRAPPING_ENABLED
&& !epilogue_completed
)
4303 && ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
== test_bb
4304 && single_succ_p (new_dest
)
4305 && single_succ (new_dest
) == EXIT_BLOCK_PTR_FOR_FN (cfun
)
4306 && bitmap_intersect_p (df_get_live_in (new_dest
), merge_set
))
4311 return_regs
= BITMAP_ALLOC (®_obstack
);
4313 /* Start off with the intersection of regs used to pass
4314 params and regs used to return values. */
4315 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
4316 if (FUNCTION_ARG_REGNO_P (i
)
4317 && targetm
.calls
.function_value_regno_p (i
))
4318 bitmap_set_bit (return_regs
, INCOMING_REGNO (i
));
4320 bitmap_and_into (return_regs
,
4321 df_get_live_out (ENTRY_BLOCK_PTR_FOR_FN (cfun
)));
4322 bitmap_and_into (return_regs
,
4323 df_get_live_in (EXIT_BLOCK_PTR_FOR_FN (cfun
)));
4324 if (!bitmap_empty_p (return_regs
))
4326 FOR_BB_INSNS_REVERSE (new_dest
, insn
)
4327 if (NONDEBUG_INSN_P (insn
))
4331 /* If this insn sets any reg in return_regs, add all
4332 reg uses to the set of regs we're interested in. */
4333 FOR_EACH_INSN_DEF (def
, insn
)
4334 if (bitmap_bit_p (return_regs
, DF_REF_REGNO (def
)))
4336 df_simulate_uses (insn
, return_regs
);
4340 if (bitmap_intersect_p (merge_set
, return_regs
))
4342 BITMAP_FREE (return_regs
);
4343 BITMAP_FREE (merge_set
);
4347 BITMAP_FREE (return_regs
);
4352 /* We don't want to use normal invert_jump or redirect_jump because
4353 we don't want to delete_insn called. Also, we want to do our own
4354 change group management. */
4356 old_dest
= JUMP_LABEL (jump
);
4357 if (other_bb
!= new_dest
)
4359 if (JUMP_P (BB_END (dest_edge
->src
)))
4360 new_dest_label
= JUMP_LABEL (BB_END (dest_edge
->src
));
4361 else if (new_dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4362 new_dest_label
= ret_rtx
;
4364 new_dest_label
= block_label (new_dest
);
4367 ? ! invert_jump_1 (jump
, new_dest_label
)
4368 : ! redirect_jump_1 (jump
, new_dest_label
))
4372 if (verify_changes (n_validated_changes
))
4373 confirm_change_group ();
4377 if (other_bb
!= new_dest
)
4379 redirect_jump_2 (jump
, old_dest
, new_dest_label
, 0, reversep
);
4381 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
4384 gcov_type count
, probability
;
4385 count
= BRANCH_EDGE (test_bb
)->count
;
4386 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
4387 FALLTHRU_EDGE (test_bb
)->count
= count
;
4388 probability
= BRANCH_EDGE (test_bb
)->probability
;
4389 BRANCH_EDGE (test_bb
)->probability
4390 = FALLTHRU_EDGE (test_bb
)->probability
;
4391 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
4392 update_br_prob_note (test_bb
);
4396 /* Move the insns out of MERGE_BB to before the branch. */
4401 if (end
== BB_END (merge_bb
))
4402 BB_END (merge_bb
) = PREV_INSN (head
);
4404 /* PR 21767: when moving insns above a conditional branch, the REG_EQUAL
4405 notes being moved might become invalid. */
4411 if (! INSN_P (insn
))
4413 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
4416 remove_note (insn
, note
);
4417 } while (insn
!= end
&& (insn
= NEXT_INSN (insn
)));
4419 /* PR46315: when moving insns above a conditional branch, the REG_EQUAL
4420 notes referring to the registers being set might become invalid. */
4426 EXECUTE_IF_SET_IN_BITMAP (merge_set
, 0, i
, bi
)
4427 remove_reg_equal_equiv_notes_for_regno (i
);
4429 BITMAP_FREE (merge_set
);
4432 reorder_insns (head
, end
, PREV_INSN (earliest
));
4435 /* Remove the jump and edge if we can. */
4436 if (other_bb
== new_dest
)
4439 remove_edge (BRANCH_EDGE (test_bb
));
4440 /* ??? Can't merge blocks here, as then_bb is still in use.
4441 At minimum, the merge will get done just before bb-reorder. */
4450 BITMAP_FREE (merge_set
);
4455 /* Main entry point for all if-conversion. AFTER_COMBINE is true if
4456 we are after combine pass. */
4459 if_convert (bool after_combine
)
4466 df_live_add_problem ();
4467 df_live_set_all_dirty ();
4470 /* Record whether we are after combine pass. */
4471 ifcvt_after_combine
= after_combine
;
4472 num_possible_if_blocks
= 0;
4473 num_updated_if_blocks
= 0;
4474 num_true_changes
= 0;
4476 loop_optimizer_init (AVOID_CFG_MODIFICATIONS
);
4477 mark_loop_exit_edges ();
4478 loop_optimizer_finalize ();
4479 free_dominance_info (CDI_DOMINATORS
);
4481 /* Compute postdominators. */
4482 calculate_dominance_info (CDI_POST_DOMINATORS
);
4484 df_set_flags (DF_LR_RUN_DCE
);
4486 /* Go through each of the basic blocks looking for things to convert. If we
4487 have conditional execution, we make multiple passes to allow us to handle
4488 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
4493 /* Only need to do dce on the first pass. */
4494 df_clear_flags (DF_LR_RUN_DCE
);
4495 cond_exec_changed_p
= FALSE
;
4498 #ifdef IFCVT_MULTIPLE_DUMPS
4499 if (dump_file
&& pass
> 1)
4500 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
4503 FOR_EACH_BB_FN (bb
, cfun
)
4506 while (!df_get_bb_dirty (bb
)
4507 && (new_bb
= find_if_header (bb
, pass
)) != NULL
)
4511 #ifdef IFCVT_MULTIPLE_DUMPS
4512 if (dump_file
&& cond_exec_changed_p
)
4513 print_rtl_with_bb (dump_file
, get_insns (), dump_flags
);
4516 while (cond_exec_changed_p
);
4518 #ifdef IFCVT_MULTIPLE_DUMPS
4520 fprintf (dump_file
, "\n\n========== no more changes\n");
4523 free_dominance_info (CDI_POST_DOMINATORS
);
4528 clear_aux_for_blocks ();
4530 /* If we allocated new pseudos, we must resize the array for sched1. */
4531 if (max_regno
< max_reg_num ())
4532 max_regno
= max_reg_num ();
4534 /* Write the final stats. */
4535 if (dump_file
&& num_possible_if_blocks
> 0)
4538 "\n%d possible IF blocks searched.\n",
4539 num_possible_if_blocks
);
4541 "%d IF blocks converted.\n",
4542 num_updated_if_blocks
);
4544 "%d true changes made.\n\n\n",
4549 df_remove_problem (df_live
);
4551 #ifdef ENABLE_CHECKING
4552 verify_flow_info ();
4556 /* If-conversion and CFG cleanup. */
4558 rest_of_handle_if_conversion (void)
4560 if (flag_if_conversion
)
4564 dump_reg_info (dump_file
);
4565 dump_flow_info (dump_file
, dump_flags
);
4567 cleanup_cfg (CLEANUP_EXPENSIVE
);
4577 const pass_data pass_data_rtl_ifcvt
=
4579 RTL_PASS
, /* type */
4581 OPTGROUP_NONE
, /* optinfo_flags */
4582 TV_IFCVT
, /* tv_id */
4583 0, /* properties_required */
4584 0, /* properties_provided */
4585 0, /* properties_destroyed */
4586 0, /* todo_flags_start */
4587 TODO_df_finish
, /* todo_flags_finish */
4590 class pass_rtl_ifcvt
: public rtl_opt_pass
4593 pass_rtl_ifcvt (gcc::context
*ctxt
)
4594 : rtl_opt_pass (pass_data_rtl_ifcvt
, ctxt
)
4597 /* opt_pass methods: */
4598 virtual bool gate (function
*)
4600 return (optimize
> 0) && dbg_cnt (if_conversion
);
4603 virtual unsigned int execute (function
*)
4605 return rest_of_handle_if_conversion ();
4608 }; // class pass_rtl_ifcvt
4613 make_pass_rtl_ifcvt (gcc::context
*ctxt
)
4615 return new pass_rtl_ifcvt (ctxt
);
4619 /* Rerun if-conversion, as combine may have simplified things enough
4620 to now meet sequence length restrictions. */
4624 const pass_data pass_data_if_after_combine
=
4626 RTL_PASS
, /* type */
4628 OPTGROUP_NONE
, /* optinfo_flags */
4629 TV_IFCVT
, /* tv_id */
4630 0, /* properties_required */
4631 0, /* properties_provided */
4632 0, /* properties_destroyed */
4633 0, /* todo_flags_start */
4634 TODO_df_finish
, /* todo_flags_finish */
4637 class pass_if_after_combine
: public rtl_opt_pass
4640 pass_if_after_combine (gcc::context
*ctxt
)
4641 : rtl_opt_pass (pass_data_if_after_combine
, ctxt
)
4644 /* opt_pass methods: */
4645 virtual bool gate (function
*)
4647 return optimize
> 0 && flag_if_conversion
4648 && dbg_cnt (if_after_combine
);
4651 virtual unsigned int execute (function
*)
4657 }; // class pass_if_after_combine
4662 make_pass_if_after_combine (gcc::context
*ctxt
)
4664 return new pass_if_after_combine (ctxt
);
4670 const pass_data pass_data_if_after_reload
=
4672 RTL_PASS
, /* type */
4674 OPTGROUP_NONE
, /* optinfo_flags */
4675 TV_IFCVT2
, /* tv_id */
4676 0, /* properties_required */
4677 0, /* properties_provided */
4678 0, /* properties_destroyed */
4679 0, /* todo_flags_start */
4680 TODO_df_finish
, /* todo_flags_finish */
4683 class pass_if_after_reload
: public rtl_opt_pass
4686 pass_if_after_reload (gcc::context
*ctxt
)
4687 : rtl_opt_pass (pass_data_if_after_reload
, ctxt
)
4690 /* opt_pass methods: */
4691 virtual bool gate (function
*)
4693 return optimize
> 0 && flag_if_conversion2
4694 && dbg_cnt (if_after_reload
);
4697 virtual unsigned int execute (function
*)
4703 }; // class pass_if_after_reload
4708 make_pass_if_after_reload (gcc::context
*ctxt
)
4710 return new pass_if_after_reload (ctxt
);