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
))
866 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
868 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
871 tmp
= emit_insn (tmp
);
873 if (recog_memoized (tmp
) >= 0)
879 if_info
->cond_earliest
= if_info
->jump
;
887 /* Don't even try if the comparison operands or the mode of X are weird. */
888 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
891 return emit_store_flag (x
, code
, XEXP (cond
, 0),
892 XEXP (cond
, 1), VOIDmode
,
893 (code
== LTU
|| code
== LEU
894 || code
== GEU
|| code
== GTU
), normalize
);
897 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
898 X is the destination/target and Y is the value to copy. */
901 noce_emit_move_insn (rtx x
, rtx y
)
903 enum machine_mode outmode
;
907 if (GET_CODE (x
) != STRICT_LOW_PART
)
909 rtx seq
, insn
, target
;
913 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
914 otherwise construct a suitable SET pattern ourselves. */
915 insn
= (OBJECT_P (y
) || CONSTANT_P (y
) || GET_CODE (y
) == SUBREG
)
916 ? emit_move_insn (x
, y
)
917 : emit_insn (gen_rtx_SET (VOIDmode
, x
, y
));
921 if (recog_memoized (insn
) <= 0)
923 if (GET_CODE (x
) == ZERO_EXTRACT
)
925 rtx op
= XEXP (x
, 0);
926 unsigned HOST_WIDE_INT size
= INTVAL (XEXP (x
, 1));
927 unsigned HOST_WIDE_INT start
= INTVAL (XEXP (x
, 2));
929 /* store_bit_field expects START to be relative to
930 BYTES_BIG_ENDIAN and adjusts this value for machines with
931 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
932 invoke store_bit_field again it is necessary to have the START
933 value from the first call. */
934 if (BITS_BIG_ENDIAN
!= BYTES_BIG_ENDIAN
)
937 start
= BITS_PER_UNIT
- start
- size
;
940 gcc_assert (REG_P (op
));
941 start
= BITS_PER_WORD
- start
- size
;
945 gcc_assert (start
< (MEM_P (op
) ? BITS_PER_UNIT
: BITS_PER_WORD
));
946 store_bit_field (op
, size
, start
, 0, 0, GET_MODE (x
), y
);
950 switch (GET_RTX_CLASS (GET_CODE (y
)))
953 ot
= code_to_optab (GET_CODE (y
));
957 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
958 if (target
!= NULL_RTX
)
961 emit_move_insn (x
, target
);
970 ot
= code_to_optab (GET_CODE (y
));
974 target
= expand_binop (GET_MODE (y
), ot
,
975 XEXP (y
, 0), XEXP (y
, 1),
977 if (target
!= NULL_RTX
)
980 emit_move_insn (x
, target
);
997 inner
= XEXP (outer
, 0);
998 outmode
= GET_MODE (outer
);
999 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
1000 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
,
1004 /* Return sequence of instructions generated by if conversion. This
1005 function calls end_sequence() to end the current stream, ensures
1006 that are instructions are unshared, recognizable non-jump insns.
1007 On failure, this function returns a NULL_RTX. */
1010 end_ifcvt_sequence (struct noce_if_info
*if_info
)
1013 rtx_insn
*seq
= get_insns ();
1015 set_used_flags (if_info
->x
);
1016 set_used_flags (if_info
->cond
);
1017 set_used_flags (if_info
->a
);
1018 set_used_flags (if_info
->b
);
1019 unshare_all_rtl_in_chain (seq
);
1022 /* Make sure that all of the instructions emitted are recognizable,
1023 and that we haven't introduced a new jump instruction.
1024 As an exercise for the reader, build a general mechanism that
1025 allows proper placement of required clobbers. */
1026 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
1028 || recog_memoized (insn
) == -1)
1034 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
1035 "if (a == b) x = a; else x = b" into "x = b". */
1038 noce_try_move (struct noce_if_info
*if_info
)
1040 rtx cond
= if_info
->cond
;
1041 enum rtx_code code
= GET_CODE (cond
);
1045 if (code
!= NE
&& code
!= EQ
)
1048 /* This optimization isn't valid if either A or B could be a NaN
1049 or a signed zero. */
1050 if (HONOR_NANS (GET_MODE (if_info
->x
))
1051 || HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
1054 /* Check whether the operands of the comparison are A and in
1056 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
1057 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
1058 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
1059 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
1061 if (!rtx_interchangeable_p (if_info
->a
, if_info
->b
))
1064 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
1066 /* Avoid generating the move if the source is the destination. */
1067 if (! rtx_equal_p (if_info
->x
, y
))
1070 noce_emit_move_insn (if_info
->x
, y
);
1071 seq
= end_ifcvt_sequence (if_info
);
1075 emit_insn_before_setloc (seq
, if_info
->jump
,
1076 INSN_LOCATION (if_info
->insn_a
));
1083 /* Convert "if (test) x = 1; else x = 0".
1085 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
1086 tried in noce_try_store_flag_constants after noce_try_cmove has had
1087 a go at the conversion. */
1090 noce_try_store_flag (struct noce_if_info
*if_info
)
1096 if (CONST_INT_P (if_info
->b
)
1097 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
1098 && if_info
->a
== const0_rtx
)
1100 else if (if_info
->b
== const0_rtx
1101 && CONST_INT_P (if_info
->a
)
1102 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
1103 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1111 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
1114 if (target
!= if_info
->x
)
1115 noce_emit_move_insn (if_info
->x
, target
);
1117 seq
= end_ifcvt_sequence (if_info
);
1121 emit_insn_before_setloc (seq
, if_info
->jump
,
1122 INSN_LOCATION (if_info
->insn_a
));
1132 /* Convert "if (test) x = a; else x = b", for A and B constant. */
1135 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
1140 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
1141 int normalize
, can_reverse
;
1142 enum machine_mode mode
;
1144 if (CONST_INT_P (if_info
->a
)
1145 && CONST_INT_P (if_info
->b
))
1147 mode
= GET_MODE (if_info
->x
);
1148 ifalse
= INTVAL (if_info
->a
);
1149 itrue
= INTVAL (if_info
->b
);
1151 diff
= (unsigned HOST_WIDE_INT
) itrue
- ifalse
;
1152 /* Make sure we can represent the difference between the two values. */
1154 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
1157 diff
= trunc_int_for_mode (diff
, mode
);
1159 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1163 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1165 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
1166 && (STORE_FLAG_VALUE
== 1
1167 || if_info
->branch_cost
>= 2))
1169 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
1170 && (STORE_FLAG_VALUE
== 1 || if_info
->branch_cost
>= 2))
1171 normalize
= 1, reversep
= 1;
1172 else if (itrue
== -1
1173 && (STORE_FLAG_VALUE
== -1
1174 || if_info
->branch_cost
>= 2))
1176 else if (ifalse
== -1 && can_reverse
1177 && (STORE_FLAG_VALUE
== -1 || if_info
->branch_cost
>= 2))
1178 normalize
= -1, reversep
= 1;
1179 else if ((if_info
->branch_cost
>= 2 && STORE_FLAG_VALUE
== -1)
1180 || if_info
->branch_cost
>= 3)
1187 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
1188 diff
= trunc_int_for_mode (-(unsigned HOST_WIDE_INT
) diff
, mode
);
1192 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
1199 /* if (test) x = 3; else x = 4;
1200 => x = 3 + (test == 0); */
1201 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1203 target
= expand_simple_binop (mode
,
1204 (diff
== STORE_FLAG_VALUE
1206 gen_int_mode (ifalse
, mode
), target
,
1207 if_info
->x
, 0, OPTAB_WIDEN
);
1210 /* if (test) x = 8; else x = 0;
1211 => x = (test != 0) << 3; */
1212 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
1214 target
= expand_simple_binop (mode
, ASHIFT
,
1215 target
, GEN_INT (tmp
), if_info
->x
, 0,
1219 /* if (test) x = -1; else x = b;
1220 => x = -(test != 0) | b; */
1221 else if (itrue
== -1)
1223 target
= expand_simple_binop (mode
, IOR
,
1224 target
, gen_int_mode (ifalse
, mode
),
1225 if_info
->x
, 0, OPTAB_WIDEN
);
1228 /* if (test) x = a; else x = b;
1229 => x = (-(test != 0) & (b - a)) + a; */
1232 target
= expand_simple_binop (mode
, AND
,
1233 target
, gen_int_mode (diff
, mode
),
1234 if_info
->x
, 0, OPTAB_WIDEN
);
1236 target
= expand_simple_binop (mode
, PLUS
,
1237 target
, gen_int_mode (ifalse
, mode
),
1238 if_info
->x
, 0, OPTAB_WIDEN
);
1247 if (target
!= if_info
->x
)
1248 noce_emit_move_insn (if_info
->x
, target
);
1250 seq
= end_ifcvt_sequence (if_info
);
1254 emit_insn_before_setloc (seq
, if_info
->jump
,
1255 INSN_LOCATION (if_info
->insn_a
));
1262 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1263 similarly for "foo--". */
1266 noce_try_addcc (struct noce_if_info
*if_info
)
1270 int subtract
, normalize
;
1272 if (GET_CODE (if_info
->a
) == PLUS
1273 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1274 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1277 rtx cond
= if_info
->cond
;
1278 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1280 /* First try to use addcc pattern. */
1281 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1282 && general_operand (XEXP (cond
, 1), VOIDmode
))
1285 target
= emit_conditional_add (if_info
->x
, code
,
1290 XEXP (if_info
->a
, 1),
1291 GET_MODE (if_info
->x
),
1292 (code
== LTU
|| code
== GEU
1293 || code
== LEU
|| code
== GTU
));
1296 if (target
!= if_info
->x
)
1297 noce_emit_move_insn (if_info
->x
, target
);
1299 seq
= end_ifcvt_sequence (if_info
);
1303 emit_insn_before_setloc (seq
, if_info
->jump
,
1304 INSN_LOCATION (if_info
->insn_a
));
1310 /* If that fails, construct conditional increment or decrement using
1312 if (if_info
->branch_cost
>= 2
1313 && (XEXP (if_info
->a
, 1) == const1_rtx
1314 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1317 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1318 subtract
= 0, normalize
= 0;
1319 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1320 subtract
= 1, normalize
= 0;
1322 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1325 target
= noce_emit_store_flag (if_info
,
1326 gen_reg_rtx (GET_MODE (if_info
->x
)),
1330 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1331 subtract
? MINUS
: PLUS
,
1332 if_info
->b
, target
, if_info
->x
,
1336 if (target
!= if_info
->x
)
1337 noce_emit_move_insn (if_info
->x
, target
);
1339 seq
= end_ifcvt_sequence (if_info
);
1343 emit_insn_before_setloc (seq
, if_info
->jump
,
1344 INSN_LOCATION (if_info
->insn_a
));
1354 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1357 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1364 if ((if_info
->branch_cost
>= 2
1365 || STORE_FLAG_VALUE
== -1)
1366 && ((if_info
->a
== const0_rtx
1367 && rtx_equal_p (if_info
->b
, if_info
->x
))
1368 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1371 && if_info
->b
== const0_rtx
1372 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1375 target
= noce_emit_store_flag (if_info
,
1376 gen_reg_rtx (GET_MODE (if_info
->x
)),
1379 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1381 target
, if_info
->x
, 0,
1386 if (target
!= if_info
->x
)
1387 noce_emit_move_insn (if_info
->x
, target
);
1389 seq
= end_ifcvt_sequence (if_info
);
1393 emit_insn_before_setloc (seq
, if_info
->jump
,
1394 INSN_LOCATION (if_info
->insn_a
));
1404 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1407 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1408 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1410 rtx target ATTRIBUTE_UNUSED
;
1411 int unsignedp ATTRIBUTE_UNUSED
;
1413 /* If earliest == jump, try to build the cmove insn directly.
1414 This is helpful when combine has created some complex condition
1415 (like for alpha's cmovlbs) that we can't hope to regenerate
1416 through the normal interface. */
1418 if (if_info
->cond_earliest
== if_info
->jump
)
1422 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1423 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
1424 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
1427 tmp
= emit_insn (tmp
);
1429 if (recog_memoized (tmp
) >= 0)
1441 /* Don't even try if the comparison operands are weird. */
1442 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1443 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1446 #if HAVE_conditional_move
1447 unsignedp
= (code
== LTU
|| code
== GEU
1448 || code
== LEU
|| code
== GTU
);
1450 target
= emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1451 vtrue
, vfalse
, GET_MODE (x
),
1456 /* We might be faced with a situation like:
1459 vtrue = (subreg:M (reg:N VTRUE) BYTE)
1460 vfalse = (subreg:M (reg:N VFALSE) BYTE)
1462 We can't do a conditional move in mode M, but it's possible that we
1463 could do a conditional move in mode N instead and take a subreg of
1466 If we can't create new pseudos, though, don't bother. */
1467 if (reload_completed
)
1470 if (GET_CODE (vtrue
) == SUBREG
&& GET_CODE (vfalse
) == SUBREG
)
1472 rtx reg_vtrue
= SUBREG_REG (vtrue
);
1473 rtx reg_vfalse
= SUBREG_REG (vfalse
);
1474 unsigned int byte_vtrue
= SUBREG_BYTE (vtrue
);
1475 unsigned int byte_vfalse
= SUBREG_BYTE (vfalse
);
1476 rtx promoted_target
;
1478 if (GET_MODE (reg_vtrue
) != GET_MODE (reg_vfalse
)
1479 || byte_vtrue
!= byte_vfalse
1480 || (SUBREG_PROMOTED_VAR_P (vtrue
)
1481 != SUBREG_PROMOTED_VAR_P (vfalse
))
1482 || (SUBREG_PROMOTED_GET (vtrue
)
1483 != SUBREG_PROMOTED_GET (vfalse
)))
1486 promoted_target
= gen_reg_rtx (GET_MODE (reg_vtrue
));
1488 target
= emit_conditional_move (promoted_target
, code
, cmp_a
, cmp_b
,
1489 VOIDmode
, reg_vtrue
, reg_vfalse
,
1490 GET_MODE (reg_vtrue
), unsignedp
);
1491 /* Nope, couldn't do it in that mode either. */
1495 target
= gen_rtx_SUBREG (GET_MODE (vtrue
), promoted_target
, byte_vtrue
);
1496 SUBREG_PROMOTED_VAR_P (target
) = SUBREG_PROMOTED_VAR_P (vtrue
);
1497 SUBREG_PROMOTED_SET (target
, SUBREG_PROMOTED_GET (vtrue
));
1498 emit_move_insn (x
, target
);
1504 /* We'll never get here, as noce_process_if_block doesn't call the
1505 functions involved. Ifdef code, however, should be discouraged
1506 because it leads to typos in the code not selected. However,
1507 emit_conditional_move won't exist either. */
1512 /* Try only simple constants and registers here. More complex cases
1513 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1514 has had a go at it. */
1517 noce_try_cmove (struct noce_if_info
*if_info
)
1523 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1524 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1528 code
= GET_CODE (if_info
->cond
);
1529 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1530 XEXP (if_info
->cond
, 0),
1531 XEXP (if_info
->cond
, 1),
1532 if_info
->a
, if_info
->b
);
1536 if (target
!= if_info
->x
)
1537 noce_emit_move_insn (if_info
->x
, target
);
1539 seq
= end_ifcvt_sequence (if_info
);
1543 emit_insn_before_setloc (seq
, if_info
->jump
,
1544 INSN_LOCATION (if_info
->insn_a
));
1557 /* Try more complex cases involving conditional_move. */
1560 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1572 /* A conditional move from two memory sources is equivalent to a
1573 conditional on their addresses followed by a load. Don't do this
1574 early because it'll screw alias analysis. Note that we've
1575 already checked for no side effects. */
1576 /* ??? FIXME: Magic number 5. */
1577 if (cse_not_expected
1578 && MEM_P (a
) && MEM_P (b
)
1579 && MEM_ADDR_SPACE (a
) == MEM_ADDR_SPACE (b
)
1580 && if_info
->branch_cost
>= 5)
1582 enum machine_mode address_mode
= get_address_mode (a
);
1586 x
= gen_reg_rtx (address_mode
);
1590 /* ??? We could handle this if we knew that a load from A or B could
1591 not trap or fault. This is also true if we've already loaded
1592 from the address along the path from ENTRY. */
1593 else if (may_trap_or_fault_p (a
) || may_trap_or_fault_p (b
))
1596 /* if (test) x = a + b; else x = c - d;
1603 code
= GET_CODE (if_info
->cond
);
1604 insn_a
= if_info
->insn_a
;
1605 insn_b
= if_info
->insn_b
;
1607 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1608 if insn_rtx_cost can't be estimated. */
1612 = insn_rtx_cost (PATTERN (insn_a
),
1613 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a
)));
1614 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1623 += insn_rtx_cost (PATTERN (insn_b
),
1624 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b
)));
1625 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1629 /* Possibly rearrange operands to make things come out more natural. */
1630 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1633 if (rtx_equal_p (b
, x
))
1635 else if (general_operand (b
, GET_MODE (b
)))
1640 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1641 tmp
= a
, a
= b
, b
= tmp
;
1642 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1651 /* If either operand is complex, load it into a register first.
1652 The best way to do this is to copy the original insn. In this
1653 way we preserve any clobbers etc that the insn may have had.
1654 This is of course not possible in the IS_MEM case. */
1655 if (! general_operand (a
, GET_MODE (a
)))
1661 tmp
= gen_reg_rtx (GET_MODE (a
));
1662 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1665 goto end_seq_and_fail
;
1668 a
= gen_reg_rtx (GET_MODE (a
));
1669 tmp
= copy_rtx (insn_a
);
1670 set
= single_set (tmp
);
1672 tmp
= emit_insn (PATTERN (tmp
));
1674 if (recog_memoized (tmp
) < 0)
1675 goto end_seq_and_fail
;
1677 if (! general_operand (b
, GET_MODE (b
)))
1683 tmp
= gen_reg_rtx (GET_MODE (b
));
1684 tmp
= gen_rtx_SET (VOIDmode
, tmp
, b
);
1687 goto end_seq_and_fail
;
1690 b
= gen_reg_rtx (GET_MODE (b
));
1691 tmp
= copy_rtx (insn_b
);
1692 set
= single_set (tmp
);
1694 tmp
= PATTERN (tmp
);
1697 /* If insn to set up A clobbers any registers B depends on, try to
1698 swap insn that sets up A with the one that sets up B. If even
1699 that doesn't help, punt. */
1700 last
= get_last_insn ();
1701 if (last
&& modified_in_p (orig_b
, last
))
1703 tmp
= emit_insn_before (tmp
, get_insns ());
1704 if (modified_in_p (orig_a
, tmp
))
1705 goto end_seq_and_fail
;
1708 tmp
= emit_insn (tmp
);
1710 if (recog_memoized (tmp
) < 0)
1711 goto end_seq_and_fail
;
1714 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1715 XEXP (if_info
->cond
, 1), a
, b
);
1718 goto end_seq_and_fail
;
1720 /* If we're handling a memory for above, emit the load now. */
1723 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1725 /* Copy over flags as appropriate. */
1726 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1727 MEM_VOLATILE_P (tmp
) = 1;
1728 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1729 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1731 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1733 gcc_assert (MEM_ADDR_SPACE (if_info
->a
) == MEM_ADDR_SPACE (if_info
->b
));
1734 set_mem_addr_space (tmp
, MEM_ADDR_SPACE (if_info
->a
));
1736 noce_emit_move_insn (if_info
->x
, tmp
);
1738 else if (target
!= x
)
1739 noce_emit_move_insn (x
, target
);
1741 tmp
= end_ifcvt_sequence (if_info
);
1745 emit_insn_before_setloc (tmp
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
1753 /* For most cases, the simplified condition we found is the best
1754 choice, but this is not the case for the min/max/abs transforms.
1755 For these we wish to know that it is A or B in the condition. */
1758 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1759 rtx_insn
**earliest
)
1765 /* If target is already mentioned in the known condition, return it. */
1766 if (reg_mentioned_p (target
, if_info
->cond
))
1768 *earliest
= if_info
->cond_earliest
;
1769 return if_info
->cond
;
1772 set
= pc_set (if_info
->jump
);
1773 cond
= XEXP (SET_SRC (set
), 0);
1775 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1776 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1777 if (if_info
->then_else_reversed
)
1780 /* If we're looking for a constant, try to make the conditional
1781 have that constant in it. There are two reasons why it may
1782 not have the constant we want:
1784 1. GCC may have needed to put the constant in a register, because
1785 the target can't compare directly against that constant. For
1786 this case, we look for a SET immediately before the comparison
1787 that puts a constant in that register.
1789 2. GCC may have canonicalized the conditional, for example
1790 replacing "if x < 4" with "if x <= 3". We can undo that (or
1791 make equivalent types of changes) to get the constants we need
1792 if they're off by one in the right direction. */
1794 if (CONST_INT_P (target
))
1796 enum rtx_code code
= GET_CODE (if_info
->cond
);
1797 rtx op_a
= XEXP (if_info
->cond
, 0);
1798 rtx op_b
= XEXP (if_info
->cond
, 1);
1801 /* First, look to see if we put a constant in a register. */
1802 prev_insn
= prev_nonnote_insn (if_info
->cond_earliest
);
1804 && BLOCK_FOR_INSN (prev_insn
)
1805 == BLOCK_FOR_INSN (if_info
->cond_earliest
)
1806 && INSN_P (prev_insn
)
1807 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1809 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1811 src
= SET_SRC (PATTERN (prev_insn
));
1812 if (CONST_INT_P (src
))
1814 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1816 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1819 if (CONST_INT_P (op_a
))
1824 code
= swap_condition (code
);
1829 /* Now, look to see if we can get the right constant by
1830 adjusting the conditional. */
1831 if (CONST_INT_P (op_b
))
1833 HOST_WIDE_INT desired_val
= INTVAL (target
);
1834 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1839 if (actual_val
== desired_val
+ 1)
1842 op_b
= GEN_INT (desired_val
);
1846 if (actual_val
== desired_val
- 1)
1849 op_b
= GEN_INT (desired_val
);
1853 if (actual_val
== desired_val
- 1)
1856 op_b
= GEN_INT (desired_val
);
1860 if (actual_val
== desired_val
+ 1)
1863 op_b
= GEN_INT (desired_val
);
1871 /* If we made any changes, generate a new conditional that is
1872 equivalent to what we started with, but has the right
1874 if (code
!= GET_CODE (if_info
->cond
)
1875 || op_a
!= XEXP (if_info
->cond
, 0)
1876 || op_b
!= XEXP (if_info
->cond
, 1))
1878 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1879 *earliest
= if_info
->cond_earliest
;
1884 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1885 earliest
, target
, false, true);
1886 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1889 /* We almost certainly searched back to a different place.
1890 Need to re-verify correct lifetimes. */
1892 /* X may not be mentioned in the range (cond_earliest, jump]. */
1893 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1894 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1897 /* A and B may not be modified in the range [cond_earliest, jump). */
1898 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1900 && (modified_in_p (if_info
->a
, insn
)
1901 || modified_in_p (if_info
->b
, insn
)))
1907 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1910 noce_try_minmax (struct noce_if_info
*if_info
)
1913 rtx_insn
*earliest
, *seq
;
1914 enum rtx_code code
, op
;
1917 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1918 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1919 to get the target to tell us... */
1920 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1921 || HONOR_NANS (GET_MODE (if_info
->x
)))
1924 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1928 /* Verify the condition is of the form we expect, and canonicalize
1929 the comparison code. */
1930 code
= GET_CODE (cond
);
1931 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1933 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1936 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1938 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1940 code
= swap_condition (code
);
1945 /* Determine what sort of operation this is. Note that the code is for
1946 a taken branch, so the code->operation mapping appears backwards. */
1979 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1980 if_info
->a
, if_info
->b
,
1981 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1987 if (target
!= if_info
->x
)
1988 noce_emit_move_insn (if_info
->x
, target
);
1990 seq
= end_ifcvt_sequence (if_info
);
1994 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
1995 if_info
->cond
= cond
;
1996 if_info
->cond_earliest
= earliest
;
2001 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
2002 "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
2006 noce_try_abs (struct noce_if_info
*if_info
)
2008 rtx cond
, target
, a
, b
, c
;
2009 rtx_insn
*earliest
, *seq
;
2011 bool one_cmpl
= false;
2013 /* Reject modes with signed zeros. */
2014 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
2017 /* Recognize A and B as constituting an ABS or NABS. The canonical
2018 form is a branch around the negation, taken when the object is the
2019 first operand of a comparison against 0 that evaluates to true. */
2022 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
2024 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
2026 c
= a
; a
= b
; b
= c
;
2029 else if (GET_CODE (a
) == NOT
&& rtx_equal_p (XEXP (a
, 0), b
))
2034 else if (GET_CODE (b
) == NOT
&& rtx_equal_p (XEXP (b
, 0), a
))
2036 c
= a
; a
= b
; b
= c
;
2043 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
2047 /* Verify the condition is of the form we expect. */
2048 if (rtx_equal_p (XEXP (cond
, 0), b
))
2050 else if (rtx_equal_p (XEXP (cond
, 1), b
))
2058 /* Verify that C is zero. Search one step backward for a
2059 REG_EQUAL note or a simple source if necessary. */
2062 rtx set
, insn
= prev_nonnote_insn (earliest
);
2064 && BLOCK_FOR_INSN (insn
) == BLOCK_FOR_INSN (earliest
)
2065 && (set
= single_set (insn
))
2066 && rtx_equal_p (SET_DEST (set
), c
))
2068 rtx note
= find_reg_equal_equiv_note (insn
);
2078 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
2079 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
2080 c
= get_pool_constant (XEXP (c
, 0));
2082 /* Work around funny ideas get_condition has wrt canonicalization.
2083 Note that these rtx constants are known to be CONST_INT, and
2084 therefore imply integer comparisons. */
2085 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
2087 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
2089 else if (c
!= CONST0_RTX (GET_MODE (b
)))
2092 /* Determine what sort of operation this is. */
2093 switch (GET_CODE (cond
))
2112 target
= expand_one_cmpl_abs_nojump (GET_MODE (if_info
->x
), b
,
2115 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
2117 /* ??? It's a quandary whether cmove would be better here, especially
2118 for integers. Perhaps combine will clean things up. */
2119 if (target
&& negate
)
2122 target
= expand_simple_unop (GET_MODE (target
), NOT
, target
,
2125 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
,
2135 if (target
!= if_info
->x
)
2136 noce_emit_move_insn (if_info
->x
, target
);
2138 seq
= end_ifcvt_sequence (if_info
);
2142 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2143 if_info
->cond
= cond
;
2144 if_info
->cond_earliest
= earliest
;
2149 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
2152 noce_try_sign_mask (struct noce_if_info
*if_info
)
2156 enum machine_mode mode
;
2158 bool t_unconditional
;
2160 cond
= if_info
->cond
;
2161 code
= GET_CODE (cond
);
2166 if (if_info
->a
== const0_rtx
)
2168 if ((code
== LT
&& c
== const0_rtx
)
2169 || (code
== LE
&& c
== constm1_rtx
))
2172 else if (if_info
->b
== const0_rtx
)
2174 if ((code
== GE
&& c
== const0_rtx
)
2175 || (code
== GT
&& c
== constm1_rtx
))
2179 if (! t
|| side_effects_p (t
))
2182 /* We currently don't handle different modes. */
2183 mode
= GET_MODE (t
);
2184 if (GET_MODE (m
) != mode
)
2187 /* This is only profitable if T is unconditionally executed/evaluated in the
2188 original insn sequence or T is cheap. The former happens if B is the
2189 non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
2190 INSN_B which can happen for e.g. conditional stores to memory. For the
2191 cost computation use the block TEST_BB where the evaluation will end up
2192 after the transformation. */
2195 && (if_info
->insn_b
== NULL_RTX
2196 || BLOCK_FOR_INSN (if_info
->insn_b
) == if_info
->test_bb
));
2197 if (!(t_unconditional
2198 || (set_src_cost (t
, optimize_bb_for_speed_p (if_info
->test_bb
))
2199 < COSTS_N_INSNS (2))))
2203 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
2204 "(signed) m >> 31" directly. This benefits targets with specialized
2205 insns to obtain the signmask, but still uses ashr_optab otherwise. */
2206 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
2207 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
2216 noce_emit_move_insn (if_info
->x
, t
);
2218 seq
= end_ifcvt_sequence (if_info
);
2222 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2227 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
2231 noce_try_bitop (struct noce_if_info
*if_info
)
2233 rtx cond
, x
, a
, result
;
2235 enum machine_mode mode
;
2240 cond
= if_info
->cond
;
2241 code
= GET_CODE (cond
);
2243 /* Check for no else condition. */
2244 if (! rtx_equal_p (x
, if_info
->b
))
2247 /* Check for a suitable condition. */
2248 if (code
!= NE
&& code
!= EQ
)
2250 if (XEXP (cond
, 1) != const0_rtx
)
2252 cond
= XEXP (cond
, 0);
2254 /* ??? We could also handle AND here. */
2255 if (GET_CODE (cond
) == ZERO_EXTRACT
)
2257 if (XEXP (cond
, 1) != const1_rtx
2258 || !CONST_INT_P (XEXP (cond
, 2))
2259 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
2261 bitnum
= INTVAL (XEXP (cond
, 2));
2262 mode
= GET_MODE (x
);
2263 if (BITS_BIG_ENDIAN
)
2264 bitnum
= GET_MODE_BITSIZE (mode
) - 1 - bitnum
;
2265 if (bitnum
< 0 || bitnum
>= HOST_BITS_PER_WIDE_INT
)
2272 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
2274 /* Check for "if (X & C) x = x op C". */
2275 if (! rtx_equal_p (x
, XEXP (a
, 0))
2276 || !CONST_INT_P (XEXP (a
, 1))
2277 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2278 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
2281 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
2282 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
2283 if (GET_CODE (a
) == IOR
)
2284 result
= (code
== NE
) ? a
: NULL_RTX
;
2285 else if (code
== NE
)
2287 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
2288 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
2289 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
2293 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2294 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
2295 result
= simplify_gen_binary (AND
, mode
, x
, result
);
2298 else if (GET_CODE (a
) == AND
)
2300 /* Check for "if (X & C) x &= ~C". */
2301 if (! rtx_equal_p (x
, XEXP (a
, 0))
2302 || !CONST_INT_P (XEXP (a
, 1))
2303 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2304 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
2307 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2308 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2309 result
= (code
== EQ
) ? a
: NULL_RTX
;
2317 noce_emit_move_insn (x
, result
);
2318 seq
= end_ifcvt_sequence (if_info
);
2322 emit_insn_before_setloc (seq
, if_info
->jump
,
2323 INSN_LOCATION (if_info
->insn_a
));
2329 /* Similar to get_condition, only the resulting condition must be
2330 valid at JUMP, instead of at EARLIEST.
2332 If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
2333 THEN block of the caller, and we have to reverse the condition. */
2336 noce_get_condition (rtx_insn
*jump
, rtx_insn
**earliest
, bool then_else_reversed
)
2341 if (! any_condjump_p (jump
))
2344 set
= pc_set (jump
);
2346 /* If this branches to JUMP_LABEL when the condition is false,
2347 reverse the condition. */
2348 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
2349 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
2351 /* We may have to reverse because the caller's if block is not canonical,
2352 i.e. the THEN block isn't the fallthrough block for the TEST block
2353 (see find_if_header). */
2354 if (then_else_reversed
)
2357 /* If the condition variable is a register and is MODE_INT, accept it. */
2359 cond
= XEXP (SET_SRC (set
), 0);
2360 tmp
= XEXP (cond
, 0);
2361 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
2362 && (GET_MODE (tmp
) != BImode
2363 || !targetm
.small_register_classes_for_mode_p (BImode
)))
2368 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
2369 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2373 /* Otherwise, fall back on canonicalize_condition to do the dirty
2374 work of manipulating MODE_CC values and COMPARE rtx codes. */
2375 tmp
= canonicalize_condition (jump
, cond
, reverse
, earliest
,
2376 NULL_RTX
, false, true);
2378 /* We don't handle side-effects in the condition, like handling
2379 REG_INC notes and making sure no duplicate conditions are emitted. */
2380 if (tmp
!= NULL_RTX
&& side_effects_p (tmp
))
2386 /* Return true if OP is ok for if-then-else processing. */
2389 noce_operand_ok (const_rtx op
)
2391 if (side_effects_p (op
))
2394 /* We special-case memories, so handle any of them with
2395 no address side effects. */
2397 return ! side_effects_p (XEXP (op
, 0));
2399 return ! may_trap_p (op
);
2402 /* Return true if a write into MEM may trap or fault. */
2405 noce_mem_write_may_trap_or_fault_p (const_rtx mem
)
2409 if (MEM_READONLY_P (mem
))
2412 if (may_trap_or_fault_p (mem
))
2415 addr
= XEXP (mem
, 0);
2417 /* Call target hook to avoid the effects of -fpic etc.... */
2418 addr
= targetm
.delegitimize_address (addr
);
2421 switch (GET_CODE (addr
))
2429 addr
= XEXP (addr
, 0);
2433 addr
= XEXP (addr
, 1);
2436 if (CONST_INT_P (XEXP (addr
, 1)))
2437 addr
= XEXP (addr
, 0);
2444 if (SYMBOL_REF_DECL (addr
)
2445 && decl_readonly_section (SYMBOL_REF_DECL (addr
), 0))
2455 /* Return whether we can use store speculation for MEM. TOP_BB is the
2456 basic block above the conditional block where we are considering
2457 doing the speculative store. We look for whether MEM is set
2458 unconditionally later in the function. */
2461 noce_can_store_speculate_p (basic_block top_bb
, const_rtx mem
)
2463 basic_block dominator
;
2465 for (dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, top_bb
);
2467 dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, dominator
))
2471 FOR_BB_INSNS (dominator
, insn
)
2473 /* If we see something that might be a memory barrier, we
2474 have to stop looking. Even if the MEM is set later in
2475 the function, we still don't want to set it
2476 unconditionally before the barrier. */
2478 && (volatile_insn_p (PATTERN (insn
))
2479 || (CALL_P (insn
) && (!RTL_CONST_CALL_P (insn
)))))
2482 if (memory_must_be_modified_in_insn_p (mem
, insn
))
2484 if (modified_in_p (XEXP (mem
, 0), insn
))
2493 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2494 it without using conditional execution. Return TRUE if we were successful
2495 at converting the block. */
2498 noce_process_if_block (struct noce_if_info
*if_info
)
2500 basic_block test_bb
= if_info
->test_bb
; /* test block */
2501 basic_block then_bb
= if_info
->then_bb
; /* THEN */
2502 basic_block else_bb
= if_info
->else_bb
; /* ELSE or NULL */
2503 basic_block join_bb
= if_info
->join_bb
; /* JOIN */
2504 rtx_insn
*jump
= if_info
->jump
;
2505 rtx cond
= if_info
->cond
;
2506 rtx_insn
*insn_a
, *insn_b
;
2508 rtx orig_x
, x
, a
, b
;
2510 /* We're looking for patterns of the form
2512 (1) if (...) x = a; else x = b;
2513 (2) x = b; if (...) x = a;
2514 (3) if (...) x = a; // as if with an initial x = x.
2516 The later patterns require jumps to be more expensive.
2518 ??? For future expansion, look for multiple X in such patterns. */
2520 /* Look for one of the potential sets. */
2521 insn_a
= first_active_insn (then_bb
);
2523 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2524 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2527 x
= SET_DEST (set_a
);
2528 a
= SET_SRC (set_a
);
2530 /* Look for the other potential set. Make sure we've got equivalent
2532 /* ??? This is overconservative. Storing to two different mems is
2533 as easy as conditionally computing the address. Storing to a
2534 single mem merely requires a scratch memory to use as one of the
2535 destination addresses; often the memory immediately below the
2536 stack pointer is available for this. */
2540 insn_b
= first_active_insn (else_bb
);
2542 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2543 || (set_b
= single_set (insn_b
)) == NULL_RTX
2544 || ! rtx_interchangeable_p (x
, SET_DEST (set_b
)))
2549 insn_b
= prev_nonnote_nondebug_insn (if_info
->cond_earliest
);
2550 /* We're going to be moving the evaluation of B down from above
2551 COND_EARLIEST to JUMP. Make sure the relevant data is still
2554 || BLOCK_FOR_INSN (insn_b
) != BLOCK_FOR_INSN (if_info
->cond_earliest
)
2555 || !NONJUMP_INSN_P (insn_b
)
2556 || (set_b
= single_set (insn_b
)) == NULL_RTX
2557 || ! rtx_interchangeable_p (x
, SET_DEST (set_b
))
2558 || ! noce_operand_ok (SET_SRC (set_b
))
2559 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2560 || modified_between_p (SET_SRC (set_b
), insn_b
, jump
)
2561 /* Avoid extending the lifetime of hard registers on small
2562 register class machines. */
2563 || (REG_P (SET_SRC (set_b
))
2564 && HARD_REGISTER_P (SET_SRC (set_b
))
2565 && targetm
.small_register_classes_for_mode_p
2566 (GET_MODE (SET_SRC (set_b
))))
2567 /* Likewise with X. In particular this can happen when
2568 noce_get_condition looks farther back in the instruction
2569 stream than one might expect. */
2570 || reg_overlap_mentioned_p (x
, cond
)
2571 || reg_overlap_mentioned_p (x
, a
)
2572 || modified_between_p (x
, insn_b
, jump
))
2579 /* If x has side effects then only the if-then-else form is safe to
2580 convert. But even in that case we would need to restore any notes
2581 (such as REG_INC) at then end. That can be tricky if
2582 noce_emit_move_insn expands to more than one insn, so disable the
2583 optimization entirely for now if there are side effects. */
2584 if (side_effects_p (x
))
2587 b
= (set_b
? SET_SRC (set_b
) : x
);
2589 /* Only operate on register destinations, and even then avoid extending
2590 the lifetime of hard registers on small register class machines. */
2593 || (HARD_REGISTER_P (x
)
2594 && targetm
.small_register_classes_for_mode_p (GET_MODE (x
))))
2596 if (GET_MODE (x
) == BLKmode
)
2599 if (GET_CODE (x
) == ZERO_EXTRACT
2600 && (!CONST_INT_P (XEXP (x
, 1))
2601 || !CONST_INT_P (XEXP (x
, 2))))
2604 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2605 ? XEXP (x
, 0) : x
));
2608 /* Don't operate on sources that may trap or are volatile. */
2609 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2613 /* Set up the info block for our subroutines. */
2614 if_info
->insn_a
= insn_a
;
2615 if_info
->insn_b
= insn_b
;
2620 /* Try optimizations in some approximation of a useful order. */
2621 /* ??? Should first look to see if X is live incoming at all. If it
2622 isn't, we don't need anything but an unconditional set. */
2624 /* Look and see if A and B are really the same. Avoid creating silly
2625 cmove constructs that no one will fix up later. */
2626 if (rtx_interchangeable_p (a
, b
))
2628 /* If we have an INSN_B, we don't have to create any new rtl. Just
2629 move the instruction that we already have. If we don't have an
2630 INSN_B, that means that A == X, and we've got a noop move. In
2631 that case don't do anything and let the code below delete INSN_A. */
2632 if (insn_b
&& else_bb
)
2636 if (else_bb
&& insn_b
== BB_END (else_bb
))
2637 BB_END (else_bb
) = PREV_INSN (insn_b
);
2638 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2640 /* If there was a REG_EQUAL note, delete it since it may have been
2641 true due to this insn being after a jump. */
2642 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2643 remove_note (insn_b
, note
);
2647 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2648 x must be executed twice. */
2649 else if (insn_b
&& side_effects_p (orig_x
))
2656 if (!set_b
&& MEM_P (orig_x
))
2658 /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
2659 for optimizations if writing to x may trap or fault,
2660 i.e. it's a memory other than a static var or a stack slot,
2661 is misaligned on strict aligned machines or is read-only. If
2662 x is a read-only memory, then the program is valid only if we
2663 avoid the store into it. If there are stores on both the
2664 THEN and ELSE arms, then we can go ahead with the conversion;
2665 either the program is broken, or the condition is always
2666 false such that the other memory is selected. */
2667 if (noce_mem_write_may_trap_or_fault_p (orig_x
))
2670 /* Avoid store speculation: given "if (...) x = a" where x is a
2671 MEM, we only want to do the store if x is always set
2672 somewhere in the function. This avoids cases like
2673 if (pthread_mutex_trylock(mutex))
2675 where we only want global_variable to be changed if the mutex
2676 is held. FIXME: This should ideally be expressed directly in
2678 if (!noce_can_store_speculate_p (test_bb
, orig_x
))
2682 if (noce_try_move (if_info
))
2684 if (noce_try_store_flag (if_info
))
2686 if (noce_try_bitop (if_info
))
2688 if (noce_try_minmax (if_info
))
2690 if (noce_try_abs (if_info
))
2692 if (HAVE_conditional_move
2693 && noce_try_cmove (if_info
))
2695 if (! targetm
.have_conditional_execution ())
2697 if (noce_try_store_flag_constants (if_info
))
2699 if (noce_try_addcc (if_info
))
2701 if (noce_try_store_flag_mask (if_info
))
2703 if (HAVE_conditional_move
2704 && noce_try_cmove_arith (if_info
))
2706 if (noce_try_sign_mask (if_info
))
2710 if (!else_bb
&& set_b
)
2722 /* If we used a temporary, fix it up now. */
2728 noce_emit_move_insn (orig_x
, x
);
2730 set_used_flags (orig_x
);
2731 unshare_all_rtl_in_chain (seq
);
2734 emit_insn_before_setloc (seq
, BB_END (test_bb
), INSN_LOCATION (insn_a
));
2737 /* The original THEN and ELSE blocks may now be removed. The test block
2738 must now jump to the join block. If the test block and the join block
2739 can be merged, do so. */
2742 delete_basic_block (else_bb
);
2746 remove_edge (find_edge (test_bb
, join_bb
));
2748 remove_edge (find_edge (then_bb
, join_bb
));
2749 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2750 delete_basic_block (then_bb
);
2753 if (can_merge_blocks_p (test_bb
, join_bb
))
2755 merge_blocks (test_bb
, join_bb
);
2759 num_updated_if_blocks
++;
2763 /* Check whether a block is suitable for conditional move conversion.
2764 Every insn must be a simple set of a register to a constant or a
2765 register. For each assignment, store the value in the pointer map
2766 VALS, keyed indexed by register pointer, then store the register
2767 pointer in REGS. COND is the condition we will test. */
2770 check_cond_move_block (basic_block bb
,
2771 hash_map
<rtx
, rtx
> *vals
,
2777 /* We can only handle simple jumps at the end of the basic block.
2778 It is almost impossible to update the CFG otherwise. */
2780 if (JUMP_P (insn
) && !onlyjump_p (insn
))
2783 FOR_BB_INSNS (bb
, insn
)
2787 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2789 set
= single_set (insn
);
2793 dest
= SET_DEST (set
);
2794 src
= SET_SRC (set
);
2796 || (HARD_REGISTER_P (dest
)
2797 && targetm
.small_register_classes_for_mode_p (GET_MODE (dest
))))
2800 if (!CONSTANT_P (src
) && !register_operand (src
, VOIDmode
))
2803 if (side_effects_p (src
) || side_effects_p (dest
))
2806 if (may_trap_p (src
) || may_trap_p (dest
))
2809 /* Don't try to handle this if the source register was
2810 modified earlier in the block. */
2813 || (GET_CODE (src
) == SUBREG
&& REG_P (SUBREG_REG (src
))
2814 && vals
->get (SUBREG_REG (src
))))
2817 /* Don't try to handle this if the destination register was
2818 modified earlier in the block. */
2819 if (vals
->get (dest
))
2822 /* Don't try to handle this if the condition uses the
2823 destination register. */
2824 if (reg_overlap_mentioned_p (dest
, cond
))
2827 /* Don't try to handle this if the source register is modified
2828 later in the block. */
2829 if (!CONSTANT_P (src
)
2830 && modified_between_p (src
, insn
, NEXT_INSN (BB_END (bb
))))
2833 vals
->put (dest
, src
);
2835 regs
->safe_push (dest
);
2841 /* Given a basic block BB suitable for conditional move conversion,
2842 a condition COND, and pointer maps THEN_VALS and ELSE_VALS containing
2843 the register values depending on COND, emit the insns in the block as
2844 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2845 processed. The caller has started a sequence for the conversion.
2846 Return true if successful, false if something goes wrong. */
2849 cond_move_convert_if_block (struct noce_if_info
*if_infop
,
2850 basic_block bb
, rtx cond
,
2851 hash_map
<rtx
, rtx
> *then_vals
,
2852 hash_map
<rtx
, rtx
> *else_vals
,
2857 rtx cond_arg0
, cond_arg1
;
2859 code
= GET_CODE (cond
);
2860 cond_arg0
= XEXP (cond
, 0);
2861 cond_arg1
= XEXP (cond
, 1);
2863 FOR_BB_INSNS (bb
, insn
)
2865 rtx set
, target
, dest
, t
, e
;
2867 /* ??? Maybe emit conditional debug insn? */
2868 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2870 set
= single_set (insn
);
2871 gcc_assert (set
&& REG_P (SET_DEST (set
)));
2873 dest
= SET_DEST (set
);
2875 rtx
*then_slot
= then_vals
->get (dest
);
2876 rtx
*else_slot
= else_vals
->get (dest
);
2877 t
= then_slot
? *then_slot
: NULL_RTX
;
2878 e
= else_slot
? *else_slot
: NULL_RTX
;
2882 /* If this register was set in the then block, we already
2883 handled this case there. */
2896 target
= noce_emit_cmove (if_infop
, dest
, code
, cond_arg0
, cond_arg1
,
2902 noce_emit_move_insn (dest
, target
);
2908 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2909 it using only conditional moves. Return TRUE if we were successful at
2910 converting the block. */
2913 cond_move_process_if_block (struct noce_if_info
*if_info
)
2915 basic_block test_bb
= if_info
->test_bb
;
2916 basic_block then_bb
= if_info
->then_bb
;
2917 basic_block else_bb
= if_info
->else_bb
;
2918 basic_block join_bb
= if_info
->join_bb
;
2919 rtx_insn
*jump
= if_info
->jump
;
2920 rtx cond
= if_info
->cond
;
2921 rtx_insn
*seq
, *loc_insn
;
2924 vec
<rtx
> then_regs
= vNULL
;
2925 vec
<rtx
> else_regs
= vNULL
;
2927 int success_p
= FALSE
;
2929 /* Build a mapping for each block to the value used for each
2931 hash_map
<rtx
, rtx
> then_vals
;
2932 hash_map
<rtx
, rtx
> else_vals
;
2934 /* Make sure the blocks are suitable. */
2935 if (!check_cond_move_block (then_bb
, &then_vals
, &then_regs
, cond
)
2937 && !check_cond_move_block (else_bb
, &else_vals
, &else_regs
, cond
)))
2940 /* Make sure the blocks can be used together. If the same register
2941 is set in both blocks, and is not set to a constant in both
2942 cases, then both blocks must set it to the same register. We
2943 have already verified that if it is set to a register, that the
2944 source register does not change after the assignment. Also count
2945 the number of registers set in only one of the blocks. */
2947 FOR_EACH_VEC_ELT (then_regs
, i
, reg
)
2949 rtx
*then_slot
= then_vals
.get (reg
);
2950 rtx
*else_slot
= else_vals
.get (reg
);
2952 gcc_checking_assert (then_slot
);
2957 rtx then_val
= *then_slot
;
2958 rtx else_val
= *else_slot
;
2959 if (!CONSTANT_P (then_val
) && !CONSTANT_P (else_val
)
2960 && !rtx_equal_p (then_val
, else_val
))
2965 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
2966 FOR_EACH_VEC_ELT (else_regs
, i
, reg
)
2968 gcc_checking_assert (else_vals
.get (reg
));
2969 if (!then_vals
.get (reg
))
2973 /* Make sure it is reasonable to convert this block. What matters
2974 is the number of assignments currently made in only one of the
2975 branches, since if we convert we are going to always execute
2977 if (c
> MAX_CONDITIONAL_EXECUTE
)
2980 /* Try to emit the conditional moves. First do the then block,
2981 then do anything left in the else blocks. */
2983 if (!cond_move_convert_if_block (if_info
, then_bb
, cond
,
2984 &then_vals
, &else_vals
, false)
2986 && !cond_move_convert_if_block (if_info
, else_bb
, cond
,
2987 &then_vals
, &else_vals
, true)))
2992 seq
= end_ifcvt_sequence (if_info
);
2996 loc_insn
= first_active_insn (then_bb
);
2999 loc_insn
= first_active_insn (else_bb
);
3000 gcc_assert (loc_insn
);
3002 emit_insn_before_setloc (seq
, jump
, INSN_LOCATION (loc_insn
));
3006 delete_basic_block (else_bb
);
3010 remove_edge (find_edge (test_bb
, join_bb
));
3012 remove_edge (find_edge (then_bb
, join_bb
));
3013 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
3014 delete_basic_block (then_bb
);
3017 if (can_merge_blocks_p (test_bb
, join_bb
))
3019 merge_blocks (test_bb
, join_bb
);
3023 num_updated_if_blocks
++;
3028 then_regs
.release ();
3029 else_regs
.release ();
3034 /* Determine if a given basic block heads a simple IF-THEN-JOIN or an
3035 IF-THEN-ELSE-JOIN block.
3037 If so, we'll try to convert the insns to not require the branch,
3038 using only transformations that do not require conditional execution.
3040 Return TRUE if we were successful at converting the block. */
3043 noce_find_if_block (basic_block test_bb
, edge then_edge
, edge else_edge
,
3046 basic_block then_bb
, else_bb
, join_bb
;
3047 bool then_else_reversed
= false;
3050 rtx_insn
*cond_earliest
;
3051 struct noce_if_info if_info
;
3053 /* We only ever should get here before reload. */
3054 gcc_assert (!reload_completed
);
3056 /* Recognize an IF-THEN-ELSE-JOIN block. */
3057 if (single_pred_p (then_edge
->dest
)
3058 && single_succ_p (then_edge
->dest
)
3059 && single_pred_p (else_edge
->dest
)
3060 && single_succ_p (else_edge
->dest
)
3061 && single_succ (then_edge
->dest
) == single_succ (else_edge
->dest
))
3063 then_bb
= then_edge
->dest
;
3064 else_bb
= else_edge
->dest
;
3065 join_bb
= single_succ (then_bb
);
3067 /* Recognize an IF-THEN-JOIN block. */
3068 else if (single_pred_p (then_edge
->dest
)
3069 && single_succ_p (then_edge
->dest
)
3070 && single_succ (then_edge
->dest
) == else_edge
->dest
)
3072 then_bb
= then_edge
->dest
;
3073 else_bb
= NULL_BLOCK
;
3074 join_bb
= else_edge
->dest
;
3076 /* Recognize an IF-ELSE-JOIN block. We can have those because the order
3077 of basic blocks in cfglayout mode does not matter, so the fallthrough
3078 edge can go to any basic block (and not just to bb->next_bb, like in
3080 else if (single_pred_p (else_edge
->dest
)
3081 && single_succ_p (else_edge
->dest
)
3082 && single_succ (else_edge
->dest
) == then_edge
->dest
)
3084 /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
3085 To make this work, we have to invert the THEN and ELSE blocks
3086 and reverse the jump condition. */
3087 then_bb
= else_edge
->dest
;
3088 else_bb
= NULL_BLOCK
;
3089 join_bb
= single_succ (then_bb
);
3090 then_else_reversed
= true;
3093 /* Not a form we can handle. */
3096 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3097 if (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3100 && single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3103 num_possible_if_blocks
++;
3108 "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
3109 (else_bb
) ? "-ELSE" : "",
3110 pass
, test_bb
->index
, then_bb
->index
);
3113 fprintf (dump_file
, ", else %d", else_bb
->index
);
3115 fprintf (dump_file
, ", join %d\n", join_bb
->index
);
3118 /* If the conditional jump is more than just a conditional
3119 jump, then we can not do if-conversion on this block. */
3120 jump
= BB_END (test_bb
);
3121 if (! onlyjump_p (jump
))
3124 /* If this is not a standard conditional jump, we can't parse it. */
3125 cond
= noce_get_condition (jump
, &cond_earliest
, then_else_reversed
);
3129 /* We must be comparing objects whose modes imply the size. */
3130 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3133 /* Initialize an IF_INFO struct to pass around. */
3134 memset (&if_info
, 0, sizeof if_info
);
3135 if_info
.test_bb
= test_bb
;
3136 if_info
.then_bb
= then_bb
;
3137 if_info
.else_bb
= else_bb
;
3138 if_info
.join_bb
= join_bb
;
3139 if_info
.cond
= cond
;
3140 if_info
.cond_earliest
= cond_earliest
;
3141 if_info
.jump
= jump
;
3142 if_info
.then_else_reversed
= then_else_reversed
;
3143 if_info
.branch_cost
= BRANCH_COST (optimize_bb_for_speed_p (test_bb
),
3144 predictable_edge_p (then_edge
));
3146 /* Do the real work. */
3148 if (noce_process_if_block (&if_info
))
3151 if (HAVE_conditional_move
3152 && cond_move_process_if_block (&if_info
))
3159 /* Merge the blocks and mark for local life update. */
3162 merge_if_block (struct ce_if_block
* ce_info
)
3164 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
3165 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
3166 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
3167 basic_block join_bb
= ce_info
->join_bb
; /* join block */
3168 basic_block combo_bb
;
3170 /* All block merging is done into the lower block numbers. */
3173 df_set_bb_dirty (test_bb
);
3175 /* Merge any basic blocks to handle && and || subtests. Each of
3176 the blocks are on the fallthru path from the predecessor block. */
3177 if (ce_info
->num_multiple_test_blocks
> 0)
3179 basic_block bb
= test_bb
;
3180 basic_block last_test_bb
= ce_info
->last_test_bb
;
3181 basic_block fallthru
= block_fallthru (bb
);
3186 fallthru
= block_fallthru (bb
);
3187 merge_blocks (combo_bb
, bb
);
3190 while (bb
!= last_test_bb
);
3193 /* Merge TEST block into THEN block. Normally the THEN block won't have a
3194 label, but it might if there were || tests. That label's count should be
3195 zero, and it normally should be removed. */
3199 /* If THEN_BB has no successors, then there's a BARRIER after it.
3200 If COMBO_BB has more than one successor (THEN_BB), then that BARRIER
3201 is no longer needed, and in fact it is incorrect to leave it in
3203 if (EDGE_COUNT (then_bb
->succs
) == 0
3204 && EDGE_COUNT (combo_bb
->succs
) > 1)
3206 rtx_insn
*end
= NEXT_INSN (BB_END (then_bb
));
3207 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3208 end
= NEXT_INSN (end
);
3210 if (end
&& BARRIER_P (end
))
3213 merge_blocks (combo_bb
, then_bb
);
3217 /* The ELSE block, if it existed, had a label. That label count
3218 will almost always be zero, but odd things can happen when labels
3219 get their addresses taken. */
3222 /* If ELSE_BB has no successors, then there's a BARRIER after it.
3223 If COMBO_BB has more than one successor (ELSE_BB), then that BARRIER
3224 is no longer needed, and in fact it is incorrect to leave it in
3226 if (EDGE_COUNT (else_bb
->succs
) == 0
3227 && EDGE_COUNT (combo_bb
->succs
) > 1)
3229 rtx_insn
*end
= NEXT_INSN (BB_END (else_bb
));
3230 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3231 end
= NEXT_INSN (end
);
3233 if (end
&& BARRIER_P (end
))
3236 merge_blocks (combo_bb
, else_bb
);
3240 /* If there was no join block reported, that means it was not adjacent
3241 to the others, and so we cannot merge them. */
3245 rtx_insn
*last
= BB_END (combo_bb
);
3247 /* The outgoing edge for the current COMBO block should already
3248 be correct. Verify this. */
3249 if (EDGE_COUNT (combo_bb
->succs
) == 0)
3250 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
3251 || (NONJUMP_INSN_P (last
)
3252 && GET_CODE (PATTERN (last
)) == TRAP_IF
3253 && (TRAP_CONDITION (PATTERN (last
))
3254 == const_true_rtx
)));
3257 /* There should still be something at the end of the THEN or ELSE
3258 blocks taking us to our final destination. */
3259 gcc_assert (JUMP_P (last
)
3260 || (EDGE_SUCC (combo_bb
, 0)->dest
3261 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3263 && SIBLING_CALL_P (last
))
3264 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
3265 && can_throw_internal (last
)));
3268 /* The JOIN block may have had quite a number of other predecessors too.
3269 Since we've already merged the TEST, THEN and ELSE blocks, we should
3270 have only one remaining edge from our if-then-else diamond. If there
3271 is more than one remaining edge, it must come from elsewhere. There
3272 may be zero incoming edges if the THEN block didn't actually join
3273 back up (as with a call to a non-return function). */
3274 else if (EDGE_COUNT (join_bb
->preds
) < 2
3275 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3277 /* We can merge the JOIN cleanly and update the dataflow try
3278 again on this pass.*/
3279 merge_blocks (combo_bb
, join_bb
);
3284 /* We cannot merge the JOIN. */
3286 /* The outgoing edge for the current COMBO block should already
3287 be correct. Verify this. */
3288 gcc_assert (single_succ_p (combo_bb
)
3289 && single_succ (combo_bb
) == join_bb
);
3291 /* Remove the jump and cruft from the end of the COMBO block. */
3292 if (join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3293 tidy_fallthru_edge (single_succ_edge (combo_bb
));
3296 num_updated_if_blocks
++;
3299 /* Find a block ending in a simple IF condition and try to transform it
3300 in some way. When converting a multi-block condition, put the new code
3301 in the first such block and delete the rest. Return a pointer to this
3302 first block if some transformation was done. Return NULL otherwise. */
3305 find_if_header (basic_block test_bb
, int pass
)
3307 ce_if_block ce_info
;
3311 /* The kind of block we're looking for has exactly two successors. */
3312 if (EDGE_COUNT (test_bb
->succs
) != 2)
3315 then_edge
= EDGE_SUCC (test_bb
, 0);
3316 else_edge
= EDGE_SUCC (test_bb
, 1);
3318 if (df_get_bb_dirty (then_edge
->dest
))
3320 if (df_get_bb_dirty (else_edge
->dest
))
3323 /* Neither edge should be abnormal. */
3324 if ((then_edge
->flags
& EDGE_COMPLEX
)
3325 || (else_edge
->flags
& EDGE_COMPLEX
))
3328 /* Nor exit the loop. */
3329 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
3330 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
3333 /* The THEN edge is canonically the one that falls through. */
3334 if (then_edge
->flags
& EDGE_FALLTHRU
)
3336 else if (else_edge
->flags
& EDGE_FALLTHRU
)
3339 else_edge
= then_edge
;
3343 /* Otherwise this must be a multiway branch of some sort. */
3346 memset (&ce_info
, 0, sizeof (ce_info
));
3347 ce_info
.test_bb
= test_bb
;
3348 ce_info
.then_bb
= then_edge
->dest
;
3349 ce_info
.else_bb
= else_edge
->dest
;
3350 ce_info
.pass
= pass
;
3352 #ifdef IFCVT_MACHDEP_INIT
3353 IFCVT_MACHDEP_INIT (&ce_info
);
3356 if (!reload_completed
3357 && noce_find_if_block (test_bb
, then_edge
, else_edge
, pass
))
3360 if (reload_completed
3361 && targetm
.have_conditional_execution ()
3362 && cond_exec_find_if_block (&ce_info
))
3366 && optab_handler (ctrap_optab
, word_mode
) != CODE_FOR_nothing
3367 && find_cond_trap (test_bb
, then_edge
, else_edge
))
3370 if (dom_info_state (CDI_POST_DOMINATORS
) >= DOM_NO_FAST_QUERY
3371 && (reload_completed
|| !targetm
.have_conditional_execution ()))
3373 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
3375 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
3383 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
3384 /* Set this so we continue looking. */
3385 cond_exec_changed_p
= TRUE
;
3386 return ce_info
.test_bb
;
3389 /* Return true if a block has two edges, one of which falls through to the next
3390 block, and the other jumps to a specific block, so that we can tell if the
3391 block is part of an && test or an || test. Returns either -1 or the number
3392 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
3395 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
3398 int fallthru_p
= FALSE
;
3405 if (!cur_bb
|| !target_bb
)
3408 /* If no edges, obviously it doesn't jump or fallthru. */
3409 if (EDGE_COUNT (cur_bb
->succs
) == 0)
3412 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
3414 if (cur_edge
->flags
& EDGE_COMPLEX
)
3415 /* Anything complex isn't what we want. */
3418 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
3421 else if (cur_edge
->dest
== target_bb
)
3428 if ((jump_p
& fallthru_p
) == 0)
3431 /* Don't allow calls in the block, since this is used to group && and ||
3432 together for conditional execution support. ??? we should support
3433 conditional execution support across calls for IA-64 some day, but
3434 for now it makes the code simpler. */
3435 end
= BB_END (cur_bb
);
3436 insn
= BB_HEAD (cur_bb
);
3438 while (insn
!= NULL_RTX
)
3445 && !DEBUG_INSN_P (insn
)
3446 && GET_CODE (PATTERN (insn
)) != USE
3447 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
3453 insn
= NEXT_INSN (insn
);
3459 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3460 block. If so, we'll try to convert the insns to not require the branch.
3461 Return TRUE if we were successful at converting the block. */
3464 cond_exec_find_if_block (struct ce_if_block
* ce_info
)
3466 basic_block test_bb
= ce_info
->test_bb
;
3467 basic_block then_bb
= ce_info
->then_bb
;
3468 basic_block else_bb
= ce_info
->else_bb
;
3469 basic_block join_bb
= NULL_BLOCK
;
3474 ce_info
->last_test_bb
= test_bb
;
3476 /* We only ever should get here after reload,
3477 and if we have conditional execution. */
3478 gcc_assert (reload_completed
&& targetm
.have_conditional_execution ());
3480 /* Discover if any fall through predecessors of the current test basic block
3481 were && tests (which jump to the else block) or || tests (which jump to
3483 if (single_pred_p (test_bb
)
3484 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
3486 basic_block bb
= single_pred (test_bb
);
3487 basic_block target_bb
;
3488 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
3491 /* Determine if the preceding block is an && or || block. */
3492 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
3494 ce_info
->and_and_p
= TRUE
;
3495 target_bb
= else_bb
;
3497 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
3499 ce_info
->and_and_p
= FALSE
;
3500 target_bb
= then_bb
;
3503 target_bb
= NULL_BLOCK
;
3505 if (target_bb
&& n_insns
<= max_insns
)
3507 int total_insns
= 0;
3510 ce_info
->last_test_bb
= test_bb
;
3512 /* Found at least one && or || block, look for more. */
3515 ce_info
->test_bb
= test_bb
= bb
;
3516 total_insns
+= n_insns
;
3519 if (!single_pred_p (bb
))
3522 bb
= single_pred (bb
);
3523 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
3525 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
3527 ce_info
->num_multiple_test_blocks
= blocks
;
3528 ce_info
->num_multiple_test_insns
= total_insns
;
3530 if (ce_info
->and_and_p
)
3531 ce_info
->num_and_and_blocks
= blocks
;
3533 ce_info
->num_or_or_blocks
= blocks
;
3537 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3538 other than any || blocks which jump to the THEN block. */
3539 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
3542 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3543 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
3545 if (cur_edge
->flags
& EDGE_COMPLEX
)
3549 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
3551 if (cur_edge
->flags
& EDGE_COMPLEX
)
3555 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3556 if (EDGE_COUNT (then_bb
->succs
) > 0
3557 && (!single_succ_p (then_bb
)
3558 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3559 || (epilogue_completed
3560 && tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
3563 /* If the THEN block has no successors, conditional execution can still
3564 make a conditional call. Don't do this unless the ELSE block has
3565 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3566 Check for the last insn of the THEN block being an indirect jump, which
3567 is listed as not having any successors, but confuses the rest of the CE
3568 code processing. ??? we should fix this in the future. */
3569 if (EDGE_COUNT (then_bb
->succs
) == 0)
3571 if (single_pred_p (else_bb
) && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3573 rtx_insn
*last_insn
= BB_END (then_bb
);
3576 && NOTE_P (last_insn
)
3577 && last_insn
!= BB_HEAD (then_bb
))
3578 last_insn
= PREV_INSN (last_insn
);
3581 && JUMP_P (last_insn
)
3582 && ! simplejump_p (last_insn
))
3586 else_bb
= NULL_BLOCK
;
3592 /* If the THEN block's successor is the other edge out of the TEST block,
3593 then we have an IF-THEN combo without an ELSE. */
3594 else if (single_succ (then_bb
) == else_bb
)
3597 else_bb
= NULL_BLOCK
;
3600 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3601 has exactly one predecessor and one successor, and the outgoing edge
3602 is not complex, then we have an IF-THEN-ELSE combo. */
3603 else if (single_succ_p (else_bb
)
3604 && single_succ (then_bb
) == single_succ (else_bb
)
3605 && single_pred_p (else_bb
)
3606 && !(single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3607 && !(epilogue_completed
3608 && tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
3609 join_bb
= single_succ (else_bb
);
3611 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3615 num_possible_if_blocks
++;
3620 "\nIF-THEN%s block found, pass %d, start block %d "
3621 "[insn %d], then %d [%d]",
3622 (else_bb
) ? "-ELSE" : "",
3625 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
3627 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
3630 fprintf (dump_file
, ", else %d [%d]",
3632 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
3634 fprintf (dump_file
, ", join %d [%d]",
3636 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
3638 if (ce_info
->num_multiple_test_blocks
> 0)
3639 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
3640 ce_info
->num_multiple_test_blocks
,
3641 (ce_info
->and_and_p
) ? "&&" : "||",
3642 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
3643 ce_info
->last_test_bb
->index
,
3644 ((BB_HEAD (ce_info
->last_test_bb
))
3645 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
3648 fputc ('\n', dump_file
);
3651 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3652 first condition for free, since we've already asserted that there's a
3653 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3654 we checked the FALLTHRU flag, those are already adjacent to the last IF
3656 /* ??? As an enhancement, move the ELSE block. Have to deal with
3657 BLOCK notes, if by no other means than backing out the merge if they
3658 exist. Sticky enough I don't want to think about it now. */
3660 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
3662 if ((next
= next
->next_bb
) != join_bb
3663 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3671 /* Do the real work. */
3673 ce_info
->else_bb
= else_bb
;
3674 ce_info
->join_bb
= join_bb
;
3676 /* If we have && and || tests, try to first handle combining the && and ||
3677 tests into the conditional code, and if that fails, go back and handle
3678 it without the && and ||, which at present handles the && case if there
3679 was no ELSE block. */
3680 if (cond_exec_process_if_block (ce_info
, TRUE
))
3683 if (ce_info
->num_multiple_test_blocks
)
3687 if (cond_exec_process_if_block (ce_info
, FALSE
))
3694 /* Convert a branch over a trap, or a branch
3695 to a trap, into a conditional trap. */
3698 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
3700 basic_block then_bb
= then_edge
->dest
;
3701 basic_block else_bb
= else_edge
->dest
;
3702 basic_block other_bb
, trap_bb
;
3703 rtx_insn
*trap
, *jump
;
3705 rtx_insn
*cond_earliest
;
3708 /* Locate the block with the trap instruction. */
3709 /* ??? While we look for no successors, we really ought to allow
3710 EH successors. Need to fix merge_if_block for that to work. */
3711 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
3712 trap_bb
= then_bb
, other_bb
= else_bb
;
3713 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
3714 trap_bb
= else_bb
, other_bb
= then_bb
;
3720 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
3721 test_bb
->index
, trap_bb
->index
);
3724 /* If this is not a standard conditional jump, we can't parse it. */
3725 jump
= BB_END (test_bb
);
3726 cond
= noce_get_condition (jump
, &cond_earliest
, false);
3730 /* If the conditional jump is more than just a conditional jump, then
3731 we can not do if-conversion on this block. */
3732 if (! onlyjump_p (jump
))
3735 /* We must be comparing objects whose modes imply the size. */
3736 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3739 /* Reverse the comparison code, if necessary. */
3740 code
= GET_CODE (cond
);
3741 if (then_bb
== trap_bb
)
3743 code
= reversed_comparison_code (cond
, jump
);
3744 if (code
== UNKNOWN
)
3748 /* Attempt to generate the conditional trap. */
3749 seq
= gen_cond_trap (code
, copy_rtx (XEXP (cond
, 0)),
3750 copy_rtx (XEXP (cond
, 1)),
3751 TRAP_CODE (PATTERN (trap
)));
3755 /* Emit the new insns before cond_earliest. */
3756 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATION (trap
));
3758 /* Delete the trap block if possible. */
3759 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
3760 df_set_bb_dirty (test_bb
);
3761 df_set_bb_dirty (then_bb
);
3762 df_set_bb_dirty (else_bb
);
3764 if (EDGE_COUNT (trap_bb
->preds
) == 0)
3766 delete_basic_block (trap_bb
);
3770 /* Wire together the blocks again. */
3771 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
3772 single_succ_edge (test_bb
)->flags
|= EDGE_FALLTHRU
;
3773 else if (trap_bb
== then_bb
)
3778 lab
= JUMP_LABEL (jump
);
3779 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
3780 LABEL_NUSES (lab
) += 1;
3781 JUMP_LABEL (newjump
) = lab
;
3782 emit_barrier_after (newjump
);
3786 if (can_merge_blocks_p (test_bb
, other_bb
))
3788 merge_blocks (test_bb
, other_bb
);
3792 num_updated_if_blocks
++;
3796 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3800 block_has_only_trap (basic_block bb
)
3804 /* We're not the exit block. */
3805 if (bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3808 /* The block must have no successors. */
3809 if (EDGE_COUNT (bb
->succs
) > 0)
3812 /* The only instruction in the THEN block must be the trap. */
3813 trap
= first_active_insn (bb
);
3814 if (! (trap
== BB_END (bb
)
3815 && GET_CODE (PATTERN (trap
)) == TRAP_IF
3816 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
3822 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3823 transformable, but not necessarily the other. There need be no
3826 Return TRUE if we were successful at converting the block.
3828 Cases we'd like to look at:
3831 if (test) goto over; // x not live
3839 if (! test) goto label;
3842 if (test) goto E; // x not live
3856 (3) // This one's really only interesting for targets that can do
3857 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3858 // it results in multiple branches on a cache line, which often
3859 // does not sit well with predictors.
3861 if (test1) goto E; // predicted not taken
3877 (A) Don't do (2) if the branch is predicted against the block we're
3878 eliminating. Do it anyway if we can eliminate a branch; this requires
3879 that the sole successor of the eliminated block postdominate the other
3882 (B) With CE, on (3) we can steal from both sides of the if, creating
3891 Again, this is most useful if J postdominates.
3893 (C) CE substitutes for helpful life information.
3895 (D) These heuristics need a lot of work. */
3897 /* Tests for case 1 above. */
3900 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3902 basic_block then_bb
= then_edge
->dest
;
3903 basic_block else_bb
= else_edge
->dest
;
3905 int then_bb_index
, then_prob
;
3906 rtx else_target
= NULL_RTX
;
3908 /* If we are partitioning hot/cold basic blocks, we don't want to
3909 mess up unconditional or indirect jumps that cross between hot
3912 Basic block partitioning may result in some jumps that appear to
3913 be optimizable (or blocks that appear to be mergeable), but which really
3914 must be left untouched (they are required to make it safely across
3915 partition boundaries). See the comments at the top of
3916 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3918 if ((BB_END (then_bb
)
3919 && JUMP_P (BB_END (then_bb
))
3920 && CROSSING_JUMP_P (BB_END (then_bb
)))
3921 || (BB_END (test_bb
)
3922 && JUMP_P (BB_END (test_bb
))
3923 && CROSSING_JUMP_P (BB_END (test_bb
)))
3924 || (BB_END (else_bb
)
3925 && JUMP_P (BB_END (else_bb
))
3926 && CROSSING_JUMP_P (BB_END (else_bb
))))
3929 /* THEN has one successor. */
3930 if (!single_succ_p (then_bb
))
3933 /* THEN does not fall through, but is not strange either. */
3934 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
3937 /* THEN has one predecessor. */
3938 if (!single_pred_p (then_bb
))
3941 /* THEN must do something. */
3942 if (forwarder_block_p (then_bb
))
3945 num_possible_if_blocks
++;
3948 "\nIF-CASE-1 found, start %d, then %d\n",
3949 test_bb
->index
, then_bb
->index
);
3951 if (then_edge
->probability
)
3952 then_prob
= REG_BR_PROB_BASE
- then_edge
->probability
;
3954 then_prob
= REG_BR_PROB_BASE
/ 2;
3956 /* We're speculating from the THEN path, we want to make sure the cost
3957 of speculation is within reason. */
3958 if (! cheap_bb_rtx_cost_p (then_bb
, then_prob
,
3959 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge
->src
),
3960 predictable_edge_p (then_edge
)))))
3963 if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3965 rtx_insn
*jump
= BB_END (else_edge
->src
);
3966 gcc_assert (JUMP_P (jump
));
3967 else_target
= JUMP_LABEL (jump
);
3970 /* Registers set are dead, or are predicable. */
3971 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
3972 single_succ_edge (then_bb
), 1))
3975 /* Conversion went ok, including moving the insns and fixing up the
3976 jump. Adjust the CFG to match. */
3978 /* We can avoid creating a new basic block if then_bb is immediately
3979 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3980 through to else_bb. */
3982 if (then_bb
->next_bb
== else_bb
3983 && then_bb
->prev_bb
== test_bb
3984 && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3986 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
3989 else if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3990 new_bb
= force_nonfallthru_and_redirect (FALLTHRU_EDGE (test_bb
),
3991 else_bb
, else_target
);
3993 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
3996 df_set_bb_dirty (test_bb
);
3997 df_set_bb_dirty (else_bb
);
3999 then_bb_index
= then_bb
->index
;
4000 delete_basic_block (then_bb
);
4002 /* Make rest of code believe that the newly created block is the THEN_BB
4003 block we removed. */
4006 df_bb_replace (then_bb_index
, new_bb
);
4007 /* This should have been done above via force_nonfallthru_and_redirect
4008 (possibly called from redirect_edge_and_branch_force). */
4009 gcc_checking_assert (BB_PARTITION (new_bb
) == BB_PARTITION (test_bb
));
4013 num_updated_if_blocks
++;
4018 /* Test for case 2 above. */
4021 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
4023 basic_block then_bb
= then_edge
->dest
;
4024 basic_block else_bb
= else_edge
->dest
;
4026 int then_prob
, else_prob
;
4028 /* We do not want to speculate (empty) loop latches. */
4030 && else_bb
->loop_father
->latch
== else_bb
)
4033 /* If we are partitioning hot/cold basic blocks, we don't want to
4034 mess up unconditional or indirect jumps that cross between hot
4037 Basic block partitioning may result in some jumps that appear to
4038 be optimizable (or blocks that appear to be mergeable), but which really
4039 must be left untouched (they are required to make it safely across
4040 partition boundaries). See the comments at the top of
4041 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4043 if ((BB_END (then_bb
)
4044 && JUMP_P (BB_END (then_bb
))
4045 && CROSSING_JUMP_P (BB_END (then_bb
)))
4046 || (BB_END (test_bb
)
4047 && JUMP_P (BB_END (test_bb
))
4048 && CROSSING_JUMP_P (BB_END (test_bb
)))
4049 || (BB_END (else_bb
)
4050 && JUMP_P (BB_END (else_bb
))
4051 && CROSSING_JUMP_P (BB_END (else_bb
))))
4054 /* ELSE has one successor. */
4055 if (!single_succ_p (else_bb
))
4058 else_succ
= single_succ_edge (else_bb
);
4060 /* ELSE outgoing edge is not complex. */
4061 if (else_succ
->flags
& EDGE_COMPLEX
)
4064 /* ELSE has one predecessor. */
4065 if (!single_pred_p (else_bb
))
4068 /* THEN is not EXIT. */
4069 if (then_bb
->index
< NUM_FIXED_BLOCKS
)
4072 if (else_edge
->probability
)
4074 else_prob
= else_edge
->probability
;
4075 then_prob
= REG_BR_PROB_BASE
- else_prob
;
4079 else_prob
= REG_BR_PROB_BASE
/ 2;
4080 then_prob
= REG_BR_PROB_BASE
/ 2;
4083 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
4084 if (else_prob
> then_prob
)
4086 else if (else_succ
->dest
->index
< NUM_FIXED_BLOCKS
4087 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
4093 num_possible_if_blocks
++;
4096 "\nIF-CASE-2 found, start %d, else %d\n",
4097 test_bb
->index
, else_bb
->index
);
4099 /* We're speculating from the ELSE path, we want to make sure the cost
4100 of speculation is within reason. */
4101 if (! cheap_bb_rtx_cost_p (else_bb
, else_prob
,
4102 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge
->src
),
4103 predictable_edge_p (else_edge
)))))
4106 /* Registers set are dead, or are predicable. */
4107 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
, 0))
4110 /* Conversion went ok, including moving the insns and fixing up the
4111 jump. Adjust the CFG to match. */
4113 df_set_bb_dirty (test_bb
);
4114 df_set_bb_dirty (then_bb
);
4115 delete_basic_block (else_bb
);
4118 num_updated_if_blocks
++;
4120 /* ??? We may now fallthru from one of THEN's successors into a join
4121 block. Rerun cleanup_cfg? Examine things manually? Wait? */
4126 /* Used by the code above to perform the actual rtl transformations.
4127 Return TRUE if successful.
4129 TEST_BB is the block containing the conditional branch. MERGE_BB
4130 is the block containing the code to manipulate. DEST_EDGE is an
4131 edge representing a jump to the join block; after the conversion,
4132 TEST_BB should be branching to its destination.
4133 REVERSEP is true if the sense of the branch should be reversed. */
4136 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
4137 basic_block other_bb
, edge dest_edge
, int reversep
)
4139 basic_block new_dest
= dest_edge
->dest
;
4140 rtx_insn
*head
, *end
, *jump
;
4141 rtx_insn
*earliest
= NULL
;
4143 bitmap merge_set
= NULL
;
4144 /* Number of pending changes. */
4145 int n_validated_changes
= 0;
4146 rtx new_dest_label
= NULL_RTX
;
4148 jump
= BB_END (test_bb
);
4150 /* Find the extent of the real code in the merge block. */
4151 head
= BB_HEAD (merge_bb
);
4152 end
= BB_END (merge_bb
);
4154 while (DEBUG_INSN_P (end
) && end
!= head
)
4155 end
= PREV_INSN (end
);
4157 /* If merge_bb ends with a tablejump, predicating/moving insn's
4158 into test_bb and then deleting merge_bb will result in the jumptable
4159 that follows merge_bb being removed along with merge_bb and then we
4160 get an unresolved reference to the jumptable. */
4161 if (tablejump_p (end
, NULL
, NULL
))
4165 head
= NEXT_INSN (head
);
4166 while (DEBUG_INSN_P (head
) && head
!= end
)
4167 head
= NEXT_INSN (head
);
4175 head
= NEXT_INSN (head
);
4176 while (DEBUG_INSN_P (head
) && head
!= end
)
4177 head
= NEXT_INSN (head
);
4182 if (!onlyjump_p (end
))
4189 end
= PREV_INSN (end
);
4190 while (DEBUG_INSN_P (end
) && end
!= head
)
4191 end
= PREV_INSN (end
);
4194 /* Don't move frame-related insn across the conditional branch. This
4195 can lead to one of the paths of the branch having wrong unwind info. */
4196 if (epilogue_completed
)
4198 rtx_insn
*insn
= head
;
4201 if (INSN_P (insn
) && RTX_FRAME_RELATED_P (insn
))
4205 insn
= NEXT_INSN (insn
);
4209 /* Disable handling dead code by conditional execution if the machine needs
4210 to do anything funny with the tests, etc. */
4211 #ifndef IFCVT_MODIFY_TESTS
4212 if (targetm
.have_conditional_execution ())
4214 /* In the conditional execution case, we have things easy. We know
4215 the condition is reversible. We don't have to check life info
4216 because we're going to conditionally execute the code anyway.
4217 All that's left is making sure the insns involved can actually
4222 cond
= cond_exec_get_condition (jump
);
4226 rtx note
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
4227 int prob_val
= (note
? XINT (note
, 0) : -1);
4231 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
4234 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
4237 prob_val
= REG_BR_PROB_BASE
- prob_val
;
4240 if (cond_exec_process_insns (NULL
, head
, end
, cond
, prob_val
, 0)
4241 && verify_changes (0))
4242 n_validated_changes
= num_validated_changes ();
4250 /* If we allocated new pseudos (e.g. in the conditional move
4251 expander called from noce_emit_cmove), we must resize the
4253 if (max_regno
< max_reg_num ())
4254 max_regno
= max_reg_num ();
4256 /* Try the NCE path if the CE path did not result in any changes. */
4257 if (n_validated_changes
== 0)
4264 /* In the non-conditional execution case, we have to verify that there
4265 are no trapping operations, no calls, no references to memory, and
4266 that any registers modified are dead at the branch site. */
4268 if (!any_condjump_p (jump
))
4271 /* Find the extent of the conditional. */
4272 cond
= noce_get_condition (jump
, &earliest
, false);
4276 live
= BITMAP_ALLOC (®_obstack
);
4277 simulate_backwards_to_point (merge_bb
, live
, end
);
4278 success
= can_move_insns_across (head
, end
, earliest
, jump
,
4280 df_get_live_in (other_bb
), NULL
);
4285 /* Collect the set of registers set in MERGE_BB. */
4286 merge_set
= BITMAP_ALLOC (®_obstack
);
4288 FOR_BB_INSNS (merge_bb
, insn
)
4289 if (NONDEBUG_INSN_P (insn
))
4290 df_simulate_find_defs (insn
, merge_set
);
4292 /* If shrink-wrapping, disable this optimization when test_bb is
4293 the first basic block and merge_bb exits. The idea is to not
4294 move code setting up a return register as that may clobber a
4295 register used to pass function parameters, which then must be
4296 saved in caller-saved regs. A caller-saved reg requires the
4297 prologue, killing a shrink-wrap opportunity. */
4298 if ((SHRINK_WRAPPING_ENABLED
&& !epilogue_completed
)
4299 && ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
== test_bb
4300 && single_succ_p (new_dest
)
4301 && single_succ (new_dest
) == EXIT_BLOCK_PTR_FOR_FN (cfun
)
4302 && bitmap_intersect_p (df_get_live_in (new_dest
), merge_set
))
4307 return_regs
= BITMAP_ALLOC (®_obstack
);
4309 /* Start off with the intersection of regs used to pass
4310 params and regs used to return values. */
4311 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
4312 if (FUNCTION_ARG_REGNO_P (i
)
4313 && targetm
.calls
.function_value_regno_p (i
))
4314 bitmap_set_bit (return_regs
, INCOMING_REGNO (i
));
4316 bitmap_and_into (return_regs
,
4317 df_get_live_out (ENTRY_BLOCK_PTR_FOR_FN (cfun
)));
4318 bitmap_and_into (return_regs
,
4319 df_get_live_in (EXIT_BLOCK_PTR_FOR_FN (cfun
)));
4320 if (!bitmap_empty_p (return_regs
))
4322 FOR_BB_INSNS_REVERSE (new_dest
, insn
)
4323 if (NONDEBUG_INSN_P (insn
))
4327 /* If this insn sets any reg in return_regs, add all
4328 reg uses to the set of regs we're interested in. */
4329 FOR_EACH_INSN_DEF (def
, insn
)
4330 if (bitmap_bit_p (return_regs
, DF_REF_REGNO (def
)))
4332 df_simulate_uses (insn
, return_regs
);
4336 if (bitmap_intersect_p (merge_set
, return_regs
))
4338 BITMAP_FREE (return_regs
);
4339 BITMAP_FREE (merge_set
);
4343 BITMAP_FREE (return_regs
);
4348 /* We don't want to use normal invert_jump or redirect_jump because
4349 we don't want to delete_insn called. Also, we want to do our own
4350 change group management. */
4352 old_dest
= JUMP_LABEL (jump
);
4353 if (other_bb
!= new_dest
)
4355 if (JUMP_P (BB_END (dest_edge
->src
)))
4356 new_dest_label
= JUMP_LABEL (BB_END (dest_edge
->src
));
4357 else if (new_dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4358 new_dest_label
= ret_rtx
;
4360 new_dest_label
= block_label (new_dest
);
4363 ? ! invert_jump_1 (jump
, new_dest_label
)
4364 : ! redirect_jump_1 (jump
, new_dest_label
))
4368 if (verify_changes (n_validated_changes
))
4369 confirm_change_group ();
4373 if (other_bb
!= new_dest
)
4375 redirect_jump_2 (jump
, old_dest
, new_dest_label
, 0, reversep
);
4377 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
4380 gcov_type count
, probability
;
4381 count
= BRANCH_EDGE (test_bb
)->count
;
4382 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
4383 FALLTHRU_EDGE (test_bb
)->count
= count
;
4384 probability
= BRANCH_EDGE (test_bb
)->probability
;
4385 BRANCH_EDGE (test_bb
)->probability
4386 = FALLTHRU_EDGE (test_bb
)->probability
;
4387 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
4388 update_br_prob_note (test_bb
);
4392 /* Move the insns out of MERGE_BB to before the branch. */
4397 if (end
== BB_END (merge_bb
))
4398 BB_END (merge_bb
) = PREV_INSN (head
);
4400 /* PR 21767: when moving insns above a conditional branch, the REG_EQUAL
4401 notes being moved might become invalid. */
4407 if (! INSN_P (insn
))
4409 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
4412 remove_note (insn
, note
);
4413 } while (insn
!= end
&& (insn
= NEXT_INSN (insn
)));
4415 /* PR46315: when moving insns above a conditional branch, the REG_EQUAL
4416 notes referring to the registers being set might become invalid. */
4422 EXECUTE_IF_SET_IN_BITMAP (merge_set
, 0, i
, bi
)
4423 remove_reg_equal_equiv_notes_for_regno (i
);
4425 BITMAP_FREE (merge_set
);
4428 reorder_insns (head
, end
, PREV_INSN (earliest
));
4431 /* Remove the jump and edge if we can. */
4432 if (other_bb
== new_dest
)
4435 remove_edge (BRANCH_EDGE (test_bb
));
4436 /* ??? Can't merge blocks here, as then_bb is still in use.
4437 At minimum, the merge will get done just before bb-reorder. */
4446 BITMAP_FREE (merge_set
);
4451 /* Main entry point for all if-conversion. AFTER_COMBINE is true if
4452 we are after combine pass. */
4455 if_convert (bool after_combine
)
4462 df_live_add_problem ();
4463 df_live_set_all_dirty ();
4466 /* Record whether we are after combine pass. */
4467 ifcvt_after_combine
= after_combine
;
4468 num_possible_if_blocks
= 0;
4469 num_updated_if_blocks
= 0;
4470 num_true_changes
= 0;
4472 loop_optimizer_init (AVOID_CFG_MODIFICATIONS
);
4473 mark_loop_exit_edges ();
4474 loop_optimizer_finalize ();
4475 free_dominance_info (CDI_DOMINATORS
);
4477 /* Compute postdominators. */
4478 calculate_dominance_info (CDI_POST_DOMINATORS
);
4480 df_set_flags (DF_LR_RUN_DCE
);
4482 /* Go through each of the basic blocks looking for things to convert. If we
4483 have conditional execution, we make multiple passes to allow us to handle
4484 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
4489 /* Only need to do dce on the first pass. */
4490 df_clear_flags (DF_LR_RUN_DCE
);
4491 cond_exec_changed_p
= FALSE
;
4494 #ifdef IFCVT_MULTIPLE_DUMPS
4495 if (dump_file
&& pass
> 1)
4496 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
4499 FOR_EACH_BB_FN (bb
, cfun
)
4502 while (!df_get_bb_dirty (bb
)
4503 && (new_bb
= find_if_header (bb
, pass
)) != NULL
)
4507 #ifdef IFCVT_MULTIPLE_DUMPS
4508 if (dump_file
&& cond_exec_changed_p
)
4509 print_rtl_with_bb (dump_file
, get_insns (), dump_flags
);
4512 while (cond_exec_changed_p
);
4514 #ifdef IFCVT_MULTIPLE_DUMPS
4516 fprintf (dump_file
, "\n\n========== no more changes\n");
4519 free_dominance_info (CDI_POST_DOMINATORS
);
4524 clear_aux_for_blocks ();
4526 /* If we allocated new pseudos, we must resize the array for sched1. */
4527 if (max_regno
< max_reg_num ())
4528 max_regno
= max_reg_num ();
4530 /* Write the final stats. */
4531 if (dump_file
&& num_possible_if_blocks
> 0)
4534 "\n%d possible IF blocks searched.\n",
4535 num_possible_if_blocks
);
4537 "%d IF blocks converted.\n",
4538 num_updated_if_blocks
);
4540 "%d true changes made.\n\n\n",
4545 df_remove_problem (df_live
);
4547 #ifdef ENABLE_CHECKING
4548 verify_flow_info ();
4552 /* If-conversion and CFG cleanup. */
4554 rest_of_handle_if_conversion (void)
4556 if (flag_if_conversion
)
4560 dump_reg_info (dump_file
);
4561 dump_flow_info (dump_file
, dump_flags
);
4563 cleanup_cfg (CLEANUP_EXPENSIVE
);
4573 const pass_data pass_data_rtl_ifcvt
=
4575 RTL_PASS
, /* type */
4577 OPTGROUP_NONE
, /* optinfo_flags */
4578 TV_IFCVT
, /* tv_id */
4579 0, /* properties_required */
4580 0, /* properties_provided */
4581 0, /* properties_destroyed */
4582 0, /* todo_flags_start */
4583 TODO_df_finish
, /* todo_flags_finish */
4586 class pass_rtl_ifcvt
: public rtl_opt_pass
4589 pass_rtl_ifcvt (gcc::context
*ctxt
)
4590 : rtl_opt_pass (pass_data_rtl_ifcvt
, ctxt
)
4593 /* opt_pass methods: */
4594 virtual bool gate (function
*)
4596 return (optimize
> 0) && dbg_cnt (if_conversion
);
4599 virtual unsigned int execute (function
*)
4601 return rest_of_handle_if_conversion ();
4604 }; // class pass_rtl_ifcvt
4609 make_pass_rtl_ifcvt (gcc::context
*ctxt
)
4611 return new pass_rtl_ifcvt (ctxt
);
4615 /* Rerun if-conversion, as combine may have simplified things enough
4616 to now meet sequence length restrictions. */
4620 const pass_data pass_data_if_after_combine
=
4622 RTL_PASS
, /* type */
4624 OPTGROUP_NONE
, /* optinfo_flags */
4625 TV_IFCVT
, /* tv_id */
4626 0, /* properties_required */
4627 0, /* properties_provided */
4628 0, /* properties_destroyed */
4629 0, /* todo_flags_start */
4630 TODO_df_finish
, /* todo_flags_finish */
4633 class pass_if_after_combine
: public rtl_opt_pass
4636 pass_if_after_combine (gcc::context
*ctxt
)
4637 : rtl_opt_pass (pass_data_if_after_combine
, ctxt
)
4640 /* opt_pass methods: */
4641 virtual bool gate (function
*)
4643 return optimize
> 0 && flag_if_conversion
4644 && dbg_cnt (if_after_combine
);
4647 virtual unsigned int execute (function
*)
4653 }; // class pass_if_after_combine
4658 make_pass_if_after_combine (gcc::context
*ctxt
)
4660 return new pass_if_after_combine (ctxt
);
4666 const pass_data pass_data_if_after_reload
=
4668 RTL_PASS
, /* type */
4670 OPTGROUP_NONE
, /* optinfo_flags */
4671 TV_IFCVT2
, /* tv_id */
4672 0, /* properties_required */
4673 0, /* properties_provided */
4674 0, /* properties_destroyed */
4675 0, /* todo_flags_start */
4676 TODO_df_finish
, /* todo_flags_finish */
4679 class pass_if_after_reload
: public rtl_opt_pass
4682 pass_if_after_reload (gcc::context
*ctxt
)
4683 : rtl_opt_pass (pass_data_if_after_reload
, ctxt
)
4686 /* opt_pass methods: */
4687 virtual bool gate (function
*)
4689 return optimize
> 0 && flag_if_conversion2
4690 && dbg_cnt (if_after_reload
);
4693 virtual unsigned int execute (function
*)
4699 }; // class pass_if_after_reload
4704 make_pass_if_after_reload (gcc::context
*ctxt
)
4706 return new pass_if_after_reload (ctxt
);