1 /* If-conversion support.
2 Copyright (C) 2000-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
31 #include "hard-reg-set.h"
35 #include "insn-config.h"
39 #include "dominance.h"
43 #include "cfgcleanup.h"
44 #include "basic-block.h"
46 #include "statistics.h"
47 #include "double-int.h"
49 #include "fixed-value.h"
63 #include "insn-codes.h"
65 #include "diagnostic-core.h"
69 #include "tree-pass.h"
72 #include "shrink-wrap.h"
75 #ifndef HAVE_conditional_move
76 #define HAVE_conditional_move 0
88 #ifndef MAX_CONDITIONAL_EXECUTE
89 #define MAX_CONDITIONAL_EXECUTE \
90 (BRANCH_COST (optimize_function_for_speed_p (cfun), false) \
94 #ifndef HAVE_cbranchcc4
95 #define HAVE_cbranchcc4 0
98 #define IFCVT_MULTIPLE_DUMPS 1
100 #define NULL_BLOCK ((basic_block) NULL)
102 /* True if after combine pass. */
103 static bool ifcvt_after_combine
;
105 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
106 static int num_possible_if_blocks
;
108 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
110 static int num_updated_if_blocks
;
112 /* # of changes made. */
113 static int num_true_changes
;
115 /* Whether conditional execution changes were made. */
116 static int cond_exec_changed_p
;
118 /* Forward references. */
119 static int count_bb_insns (const_basic_block
);
120 static bool cheap_bb_rtx_cost_p (const_basic_block
, int, int);
121 static rtx_insn
*first_active_insn (basic_block
);
122 static rtx_insn
*last_active_insn (basic_block
, int);
123 static rtx_insn
*find_active_insn_before (basic_block
, rtx_insn
*);
124 static rtx_insn
*find_active_insn_after (basic_block
, rtx_insn
*);
125 static basic_block
block_fallthru (basic_block
);
126 static int cond_exec_process_insns (ce_if_block
*, rtx_insn
*, rtx
, rtx
, int,
128 static rtx
cond_exec_get_condition (rtx_insn
*);
129 static rtx
noce_get_condition (rtx_insn
*, rtx_insn
**, bool);
130 static int noce_operand_ok (const_rtx
);
131 static void merge_if_block (ce_if_block
*);
132 static int find_cond_trap (basic_block
, edge
, edge
);
133 static basic_block
find_if_header (basic_block
, int);
134 static int block_jumps_and_fallthru_p (basic_block
, basic_block
);
135 static int noce_find_if_block (basic_block
, edge
, edge
, int);
136 static int cond_exec_find_if_block (ce_if_block
*);
137 static int find_if_case_1 (basic_block
, edge
, edge
);
138 static int find_if_case_2 (basic_block
, edge
, edge
);
139 static int dead_or_predicable (basic_block
, basic_block
, basic_block
,
141 static void noce_emit_move_insn (rtx
, rtx
);
142 static rtx_insn
*block_has_only_trap (basic_block
);
144 /* Count the number of non-jump active insns in BB. */
147 count_bb_insns (const_basic_block bb
)
150 rtx_insn
*insn
= BB_HEAD (bb
);
154 if (active_insn_p (insn
) && !JUMP_P (insn
))
157 if (insn
== BB_END (bb
))
159 insn
= NEXT_INSN (insn
);
165 /* Determine whether the total insn_rtx_cost on non-jump insns in
166 basic block BB is less than MAX_COST. This function returns
167 false if the cost of any instruction could not be estimated.
169 The cost of the non-jump insns in BB is scaled by REG_BR_PROB_BASE
170 as those insns are being speculated. MAX_COST is scaled with SCALE
171 plus a small fudge factor. */
174 cheap_bb_rtx_cost_p (const_basic_block bb
, int scale
, int max_cost
)
177 rtx_insn
*insn
= BB_HEAD (bb
);
178 bool speed
= optimize_bb_for_speed_p (bb
);
180 /* Set scale to REG_BR_PROB_BASE to void the identical scaling
181 applied to insn_rtx_cost when optimizing for size. Only do
182 this after combine because if-conversion might interfere with
183 passes before combine.
185 Use optimize_function_for_speed_p instead of the pre-defined
186 variable speed to make sure it is set to same value for all
187 basic blocks in one if-conversion transformation. */
188 if (!optimize_function_for_speed_p (cfun
) && ifcvt_after_combine
)
189 scale
= REG_BR_PROB_BASE
;
190 /* Our branch probability/scaling factors are just estimates and don't
191 account for cases where we can get speculation for free and other
192 secondary benefits. So we fudge the scale factor to make speculating
193 appear a little more profitable when optimizing for performance. */
195 scale
+= REG_BR_PROB_BASE
/ 8;
202 if (NONJUMP_INSN_P (insn
))
204 int cost
= insn_rtx_cost (PATTERN (insn
), speed
) * REG_BR_PROB_BASE
;
208 /* If this instruction is the load or set of a "stack" register,
209 such as a floating point register on x87, then the cost of
210 speculatively executing this insn may need to include
211 the additional cost of popping its result off of the
212 register stack. Unfortunately, correctly recognizing and
213 accounting for this additional overhead is tricky, so for
214 now we simply prohibit such speculative execution. */
217 rtx set
= single_set (insn
);
218 if (set
&& STACK_REG_P (SET_DEST (set
)))
224 if (count
>= max_cost
)
227 else if (CALL_P (insn
))
230 if (insn
== BB_END (bb
))
232 insn
= NEXT_INSN (insn
);
238 /* Return the first non-jump active insn in the basic block. */
241 first_active_insn (basic_block bb
)
243 rtx_insn
*insn
= BB_HEAD (bb
);
247 if (insn
== BB_END (bb
))
249 insn
= NEXT_INSN (insn
);
252 while (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
254 if (insn
== BB_END (bb
))
256 insn
= NEXT_INSN (insn
);
265 /* Return the last non-jump active (non-jump) insn in the basic block. */
268 last_active_insn (basic_block bb
, int skip_use_p
)
270 rtx_insn
*insn
= BB_END (bb
);
271 rtx_insn
*head
= BB_HEAD (bb
);
275 || DEBUG_INSN_P (insn
)
277 && NONJUMP_INSN_P (insn
)
278 && GET_CODE (PATTERN (insn
)) == USE
))
282 insn
= PREV_INSN (insn
);
291 /* Return the active insn before INSN inside basic block CURR_BB. */
294 find_active_insn_before (basic_block curr_bb
, rtx_insn
*insn
)
296 if (!insn
|| insn
== BB_HEAD (curr_bb
))
299 while ((insn
= PREV_INSN (insn
)) != NULL_RTX
)
301 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
304 /* No other active insn all the way to the start of the basic block. */
305 if (insn
== BB_HEAD (curr_bb
))
312 /* Return the active insn after INSN inside basic block CURR_BB. */
315 find_active_insn_after (basic_block curr_bb
, rtx_insn
*insn
)
317 if (!insn
|| insn
== BB_END (curr_bb
))
320 while ((insn
= NEXT_INSN (insn
)) != NULL_RTX
)
322 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
325 /* No other active insn all the way to the end of the basic block. */
326 if (insn
== BB_END (curr_bb
))
333 /* Return the basic block reached by falling though the basic block BB. */
336 block_fallthru (basic_block bb
)
338 edge e
= find_fallthru_edge (bb
->succs
);
340 return (e
) ? e
->dest
: NULL_BLOCK
;
343 /* Return true if RTXs A and B can be safely interchanged. */
346 rtx_interchangeable_p (const_rtx a
, const_rtx b
)
348 if (!rtx_equal_p (a
, b
))
351 if (GET_CODE (a
) != MEM
)
354 /* A dead type-unsafe memory reference is legal, but a live type-unsafe memory
355 reference is not. Interchanging a dead type-unsafe memory reference with
356 a live type-safe one creates a live type-unsafe memory reference, in other
357 words, it makes the program illegal.
358 We check here conservatively whether the two memory references have equal
359 memory attributes. */
361 return mem_attrs_eq_p (get_mem_attrs (a
), get_mem_attrs (b
));
365 /* Go through a bunch of insns, converting them to conditional
366 execution format if possible. Return TRUE if all of the non-note
367 insns were processed. */
370 cond_exec_process_insns (ce_if_block
*ce_info ATTRIBUTE_UNUSED
,
371 /* if block information */rtx_insn
*start
,
372 /* first insn to look at */rtx end
,
373 /* last insn to look at */rtx test
,
374 /* conditional execution test */int prob_val
,
375 /* probability of branch taken. */int mod_ok
)
377 int must_be_last
= FALSE
;
385 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
387 /* dwarf2out can't cope with conditional prologues. */
388 if (NOTE_P (insn
) && NOTE_KIND (insn
) == NOTE_INSN_PROLOGUE_END
)
391 if (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
394 gcc_assert (NONJUMP_INSN_P (insn
) || CALL_P (insn
));
396 /* dwarf2out can't cope with conditional unwind info. */
397 if (RTX_FRAME_RELATED_P (insn
))
400 /* Remove USE insns that get in the way. */
401 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
403 /* ??? Ug. Actually unlinking the thing is problematic,
404 given what we'd have to coordinate with our callers. */
405 SET_INSN_DELETED (insn
);
409 /* Last insn wasn't last? */
413 if (modified_in_p (test
, insn
))
420 /* Now build the conditional form of the instruction. */
421 pattern
= PATTERN (insn
);
422 xtest
= copy_rtx (test
);
424 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
426 if (GET_CODE (pattern
) == COND_EXEC
)
428 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
431 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
432 COND_EXEC_TEST (pattern
));
433 pattern
= COND_EXEC_CODE (pattern
);
436 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
438 /* If the machine needs to modify the insn being conditionally executed,
439 say for example to force a constant integer operand into a temp
440 register, do so here. */
441 #ifdef IFCVT_MODIFY_INSN
442 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
447 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
449 if (CALL_P (insn
) && prob_val
>= 0)
450 validate_change (insn
, ®_NOTES (insn
),
451 gen_rtx_INT_LIST ((machine_mode
) REG_BR_PROB
,
452 prob_val
, REG_NOTES (insn
)), 1);
462 /* Return the condition for a jump. Do not do any special processing. */
465 cond_exec_get_condition (rtx_insn
*jump
)
469 if (any_condjump_p (jump
))
470 test_if
= SET_SRC (pc_set (jump
));
473 cond
= XEXP (test_if
, 0);
475 /* If this branches to JUMP_LABEL when the condition is false,
476 reverse the condition. */
477 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
478 && LABEL_REF_LABEL (XEXP (test_if
, 2)) == JUMP_LABEL (jump
))
480 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
484 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
491 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
492 to conditional execution. Return TRUE if we were successful at
493 converting the block. */
496 cond_exec_process_if_block (ce_if_block
* ce_info
,
497 /* if block information */int do_multiple_p
)
499 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
500 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
501 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
502 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
503 rtx_insn
*then_start
; /* first insn in THEN block */
504 rtx_insn
*then_end
; /* last insn + 1 in THEN block */
505 rtx_insn
*else_start
= NULL
; /* first insn in ELSE block or NULL */
506 rtx_insn
*else_end
= NULL
; /* last insn + 1 in ELSE block */
507 int max
; /* max # of insns to convert. */
508 int then_mod_ok
; /* whether conditional mods are ok in THEN */
509 rtx true_expr
; /* test for else block insns */
510 rtx false_expr
; /* test for then block insns */
511 int true_prob_val
; /* probability of else block */
512 int false_prob_val
; /* probability of then block */
513 rtx_insn
*then_last_head
= NULL
; /* Last match at the head of THEN */
514 rtx_insn
*else_last_head
= NULL
; /* Last match at the head of ELSE */
515 rtx_insn
*then_first_tail
= NULL
; /* First match at the tail of THEN */
516 rtx_insn
*else_first_tail
= NULL
; /* First match at the tail of ELSE */
517 int then_n_insns
, else_n_insns
, n_insns
;
518 enum rtx_code false_code
;
521 /* If test is comprised of && or || elements, and we've failed at handling
522 all of them together, just use the last test if it is the special case of
523 && elements without an ELSE block. */
524 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
526 if (else_bb
|| ! ce_info
->and_and_p
)
529 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
530 ce_info
->num_multiple_test_blocks
= 0;
531 ce_info
->num_and_and_blocks
= 0;
532 ce_info
->num_or_or_blocks
= 0;
535 /* Find the conditional jump to the ELSE or JOIN part, and isolate
537 test_expr
= cond_exec_get_condition (BB_END (test_bb
));
541 /* If the conditional jump is more than just a conditional jump,
542 then we can not do conditional execution conversion on this block. */
543 if (! onlyjump_p (BB_END (test_bb
)))
546 /* Collect the bounds of where we're to search, skipping any labels, jumps
547 and notes at the beginning and end of the block. Then count the total
548 number of insns and see if it is small enough to convert. */
549 then_start
= first_active_insn (then_bb
);
550 then_end
= last_active_insn (then_bb
, TRUE
);
551 then_n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
552 n_insns
= then_n_insns
;
553 max
= MAX_CONDITIONAL_EXECUTE
;
560 else_start
= first_active_insn (else_bb
);
561 else_end
= last_active_insn (else_bb
, TRUE
);
562 else_n_insns
= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
563 n_insns
+= else_n_insns
;
565 /* Look for matching sequences at the head and tail of the two blocks,
566 and limit the range of insns to be converted if possible. */
567 n_matching
= flow_find_cross_jump (then_bb
, else_bb
,
568 &then_first_tail
, &else_first_tail
,
570 if (then_first_tail
== BB_HEAD (then_bb
))
571 then_start
= then_end
= NULL
;
572 if (else_first_tail
== BB_HEAD (else_bb
))
573 else_start
= else_end
= NULL
;
578 then_end
= find_active_insn_before (then_bb
, then_first_tail
);
580 else_end
= find_active_insn_before (else_bb
, else_first_tail
);
581 n_insns
-= 2 * n_matching
;
586 && then_n_insns
> n_matching
587 && else_n_insns
> n_matching
)
589 int longest_match
= MIN (then_n_insns
- n_matching
,
590 else_n_insns
- n_matching
);
592 = flow_find_head_matching_sequence (then_bb
, else_bb
,
601 /* We won't pass the insns in the head sequence to
602 cond_exec_process_insns, so we need to test them here
603 to make sure that they don't clobber the condition. */
604 for (insn
= BB_HEAD (then_bb
);
605 insn
!= NEXT_INSN (then_last_head
);
606 insn
= NEXT_INSN (insn
))
607 if (!LABEL_P (insn
) && !NOTE_P (insn
)
608 && !DEBUG_INSN_P (insn
)
609 && modified_in_p (test_expr
, insn
))
613 if (then_last_head
== then_end
)
614 then_start
= then_end
= NULL
;
615 if (else_last_head
== else_end
)
616 else_start
= else_end
= NULL
;
621 then_start
= find_active_insn_after (then_bb
, then_last_head
);
623 else_start
= find_active_insn_after (else_bb
, else_last_head
);
624 n_insns
-= 2 * n_matching
;
632 /* Map test_expr/test_jump into the appropriate MD tests to use on
633 the conditionally executed code. */
635 true_expr
= test_expr
;
637 false_code
= reversed_comparison_code (true_expr
, BB_END (test_bb
));
638 if (false_code
!= UNKNOWN
)
639 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
640 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
642 false_expr
= NULL_RTX
;
644 #ifdef IFCVT_MODIFY_TESTS
645 /* If the machine description needs to modify the tests, such as setting a
646 conditional execution register from a comparison, it can do so here. */
647 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
649 /* See if the conversion failed. */
650 if (!true_expr
|| !false_expr
)
654 note
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
657 true_prob_val
= XINT (note
, 0);
658 false_prob_val
= REG_BR_PROB_BASE
- true_prob_val
;
666 /* If we have && or || tests, do them here. These tests are in the adjacent
667 blocks after the first block containing the test. */
668 if (ce_info
->num_multiple_test_blocks
> 0)
670 basic_block bb
= test_bb
;
671 basic_block last_test_bb
= ce_info
->last_test_bb
;
678 rtx_insn
*start
, *end
;
680 enum rtx_code f_code
;
682 bb
= block_fallthru (bb
);
683 start
= first_active_insn (bb
);
684 end
= last_active_insn (bb
, TRUE
);
686 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
687 false_prob_val
, FALSE
))
690 /* If the conditional jump is more than just a conditional jump, then
691 we can not do conditional execution conversion on this block. */
692 if (! onlyjump_p (BB_END (bb
)))
695 /* Find the conditional jump and isolate the test. */
696 t
= cond_exec_get_condition (BB_END (bb
));
700 f_code
= reversed_comparison_code (t
, BB_END (bb
));
701 if (f_code
== UNKNOWN
)
704 f
= gen_rtx_fmt_ee (f_code
, GET_MODE (t
), XEXP (t
, 0), XEXP (t
, 1));
705 if (ce_info
->and_and_p
)
707 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
708 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
712 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
713 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
716 /* If the machine description needs to modify the tests, such as
717 setting a conditional execution register from a comparison, it can
719 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
720 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
722 /* See if the conversion failed. */
730 while (bb
!= last_test_bb
);
733 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
734 on then THEN block. */
735 then_mod_ok
= (else_bb
== NULL_BLOCK
);
737 /* Go through the THEN and ELSE blocks converting the insns if possible
738 to conditional execution. */
742 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
743 false_expr
, false_prob_val
,
747 if (else_bb
&& else_end
748 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
749 true_expr
, true_prob_val
, TRUE
))
752 /* If we cannot apply the changes, fail. Do not go through the normal fail
753 processing, since apply_change_group will call cancel_changes. */
754 if (! apply_change_group ())
756 #ifdef IFCVT_MODIFY_CANCEL
757 /* Cancel any machine dependent changes. */
758 IFCVT_MODIFY_CANCEL (ce_info
);
763 #ifdef IFCVT_MODIFY_FINAL
764 /* Do any machine dependent final modifications. */
765 IFCVT_MODIFY_FINAL (ce_info
);
768 /* Conversion succeeded. */
770 fprintf (dump_file
, "%d insn%s converted to conditional execution.\n",
771 n_insns
, (n_insns
== 1) ? " was" : "s were");
773 /* Merge the blocks! If we had matching sequences, make sure to delete one
774 copy at the appropriate location first: delete the copy in the THEN branch
775 for a tail sequence so that the remaining one is executed last for both
776 branches, and delete the copy in the ELSE branch for a head sequence so
777 that the remaining one is executed first for both branches. */
780 rtx_insn
*from
= then_first_tail
;
782 from
= find_active_insn_after (then_bb
, from
);
783 delete_insn_chain (from
, BB_END (then_bb
), false);
786 delete_insn_chain (first_active_insn (else_bb
), else_last_head
, false);
788 merge_if_block (ce_info
);
789 cond_exec_changed_p
= TRUE
;
793 #ifdef IFCVT_MODIFY_CANCEL
794 /* Cancel any machine dependent changes. */
795 IFCVT_MODIFY_CANCEL (ce_info
);
802 /* Used by noce_process_if_block to communicate with its subroutines.
804 The subroutines know that A and B may be evaluated freely. They
805 know that X is a register. They should insert new instructions
806 before cond_earliest. */
810 /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block. */
811 basic_block test_bb
, then_bb
, else_bb
, join_bb
;
813 /* The jump that ends TEST_BB. */
816 /* The jump condition. */
819 /* New insns should be inserted before this one. */
820 rtx_insn
*cond_earliest
;
822 /* Insns in the THEN and ELSE block. There is always just this
823 one insns in those blocks. The insns are single_set insns.
824 If there was no ELSE block, INSN_B is the last insn before
825 COND_EARLIEST, or NULL_RTX. In the former case, the insn
826 operands are still valid, as if INSN_B was moved down below
828 rtx_insn
*insn_a
, *insn_b
;
830 /* The SET_SRC of INSN_A and INSN_B. */
833 /* The SET_DEST of INSN_A. */
836 /* True if this if block is not canonical. In the canonical form of
837 if blocks, the THEN_BB is the block reached via the fallthru edge
838 from TEST_BB. For the noce transformations, we allow the symmetric
840 bool then_else_reversed
;
842 /* Estimated cost of the particular branch instruction. */
846 static rtx
noce_emit_store_flag (struct noce_if_info
*, rtx
, int, int);
847 static int noce_try_move (struct noce_if_info
*);
848 static int noce_try_store_flag (struct noce_if_info
*);
849 static int noce_try_addcc (struct noce_if_info
*);
850 static int noce_try_store_flag_constants (struct noce_if_info
*);
851 static int noce_try_store_flag_mask (struct noce_if_info
*);
852 static rtx
noce_emit_cmove (struct noce_if_info
*, rtx
, enum rtx_code
, rtx
,
854 static int noce_try_cmove (struct noce_if_info
*);
855 static int noce_try_cmove_arith (struct noce_if_info
*);
856 static rtx
noce_get_alt_condition (struct noce_if_info
*, rtx
, rtx_insn
**);
857 static int noce_try_minmax (struct noce_if_info
*);
858 static int noce_try_abs (struct noce_if_info
*);
859 static int noce_try_sign_mask (struct noce_if_info
*);
861 /* Helper function for noce_try_store_flag*. */
864 noce_emit_store_flag (struct noce_if_info
*if_info
, rtx x
, int reversep
,
867 rtx cond
= if_info
->cond
;
871 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
872 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
874 /* If earliest == jump, or when the condition is complex, try to
875 build the store_flag insn directly. */
879 rtx set
= pc_set (if_info
->jump
);
880 cond
= XEXP (SET_SRC (set
), 0);
881 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
882 && LABEL_REF_LABEL (XEXP (SET_SRC (set
), 2)) == JUMP_LABEL (if_info
->jump
))
883 reversep
= !reversep
;
884 if (if_info
->then_else_reversed
)
885 reversep
= !reversep
;
889 code
= reversed_comparison_code (cond
, if_info
->jump
);
891 code
= GET_CODE (cond
);
893 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
894 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
896 rtx src
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
898 rtx set
= gen_rtx_SET (VOIDmode
, x
, src
);
901 rtx_insn
*insn
= emit_insn (set
);
903 if (recog_memoized (insn
) >= 0)
905 rtx_insn
*seq
= get_insns ();
909 if_info
->cond_earliest
= if_info
->jump
;
917 /* Don't even try if the comparison operands or the mode of X are weird. */
918 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
921 return emit_store_flag (x
, code
, XEXP (cond
, 0),
922 XEXP (cond
, 1), VOIDmode
,
923 (code
== LTU
|| code
== LEU
924 || code
== GEU
|| code
== GTU
), normalize
);
927 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
928 X is the destination/target and Y is the value to copy. */
931 noce_emit_move_insn (rtx x
, rtx y
)
933 machine_mode outmode
;
937 if (GET_CODE (x
) != STRICT_LOW_PART
)
939 rtx_insn
*seq
, *insn
;
944 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
945 otherwise construct a suitable SET pattern ourselves. */
946 insn
= (OBJECT_P (y
) || CONSTANT_P (y
) || GET_CODE (y
) == SUBREG
)
947 ? emit_move_insn (x
, y
)
948 : emit_insn (gen_rtx_SET (VOIDmode
, x
, y
));
952 if (recog_memoized (insn
) <= 0)
954 if (GET_CODE (x
) == ZERO_EXTRACT
)
956 rtx op
= XEXP (x
, 0);
957 unsigned HOST_WIDE_INT size
= INTVAL (XEXP (x
, 1));
958 unsigned HOST_WIDE_INT start
= INTVAL (XEXP (x
, 2));
960 /* store_bit_field expects START to be relative to
961 BYTES_BIG_ENDIAN and adjusts this value for machines with
962 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
963 invoke store_bit_field again it is necessary to have the START
964 value from the first call. */
965 if (BITS_BIG_ENDIAN
!= BYTES_BIG_ENDIAN
)
968 start
= BITS_PER_UNIT
- start
- size
;
971 gcc_assert (REG_P (op
));
972 start
= BITS_PER_WORD
- start
- size
;
976 gcc_assert (start
< (MEM_P (op
) ? BITS_PER_UNIT
: BITS_PER_WORD
));
977 store_bit_field (op
, size
, start
, 0, 0, GET_MODE (x
), y
);
981 switch (GET_RTX_CLASS (GET_CODE (y
)))
984 ot
= code_to_optab (GET_CODE (y
));
988 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
989 if (target
!= NULL_RTX
)
992 emit_move_insn (x
, target
);
1000 case RTX_COMM_ARITH
:
1001 ot
= code_to_optab (GET_CODE (y
));
1005 target
= expand_binop (GET_MODE (y
), ot
,
1006 XEXP (y
, 0), XEXP (y
, 1),
1007 x
, 0, OPTAB_DIRECT
);
1008 if (target
!= NULL_RTX
)
1011 emit_move_insn (x
, target
);
1027 outer
= XEXP (x
, 0);
1028 inner
= XEXP (outer
, 0);
1029 outmode
= GET_MODE (outer
);
1030 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
1031 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
,
1035 /* Return the CC reg if it is used in COND. */
1038 cc_in_cond (rtx cond
)
1040 if (HAVE_cbranchcc4
&& cond
1041 && GET_MODE_CLASS (GET_MODE (XEXP (cond
, 0))) == MODE_CC
)
1042 return XEXP (cond
, 0);
1047 /* Return sequence of instructions generated by if conversion. This
1048 function calls end_sequence() to end the current stream, ensures
1049 that are instructions are unshared, recognizable non-jump insns.
1050 On failure, this function returns a NULL_RTX. */
1053 end_ifcvt_sequence (struct noce_if_info
*if_info
)
1056 rtx_insn
*seq
= get_insns ();
1057 rtx cc
= cc_in_cond (if_info
->cond
);
1059 set_used_flags (if_info
->x
);
1060 set_used_flags (if_info
->cond
);
1061 set_used_flags (if_info
->a
);
1062 set_used_flags (if_info
->b
);
1063 unshare_all_rtl_in_chain (seq
);
1066 /* Make sure that all of the instructions emitted are recognizable,
1067 and that we haven't introduced a new jump instruction.
1068 As an exercise for the reader, build a general mechanism that
1069 allows proper placement of required clobbers. */
1070 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
1072 || recog_memoized (insn
) == -1
1073 /* Make sure new generated code does not clobber CC. */
1074 || (cc
&& set_of (cc
, insn
)))
1080 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
1081 "if (a == b) x = a; else x = b" into "x = b". */
1084 noce_try_move (struct noce_if_info
*if_info
)
1086 rtx cond
= if_info
->cond
;
1087 enum rtx_code code
= GET_CODE (cond
);
1091 if (code
!= NE
&& code
!= EQ
)
1094 /* This optimization isn't valid if either A or B could be a NaN
1095 or a signed zero. */
1096 if (HONOR_NANS (if_info
->x
)
1097 || HONOR_SIGNED_ZEROS (if_info
->x
))
1100 /* Check whether the operands of the comparison are A and in
1102 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
1103 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
1104 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
1105 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
1107 if (!rtx_interchangeable_p (if_info
->a
, if_info
->b
))
1110 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
1112 /* Avoid generating the move if the source is the destination. */
1113 if (! rtx_equal_p (if_info
->x
, y
))
1116 noce_emit_move_insn (if_info
->x
, y
);
1117 seq
= end_ifcvt_sequence (if_info
);
1121 emit_insn_before_setloc (seq
, if_info
->jump
,
1122 INSN_LOCATION (if_info
->insn_a
));
1129 /* Convert "if (test) x = 1; else x = 0".
1131 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
1132 tried in noce_try_store_flag_constants after noce_try_cmove has had
1133 a go at the conversion. */
1136 noce_try_store_flag (struct noce_if_info
*if_info
)
1142 if (CONST_INT_P (if_info
->b
)
1143 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
1144 && if_info
->a
== const0_rtx
)
1146 else if (if_info
->b
== const0_rtx
1147 && CONST_INT_P (if_info
->a
)
1148 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
1149 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1157 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
1160 if (target
!= if_info
->x
)
1161 noce_emit_move_insn (if_info
->x
, target
);
1163 seq
= end_ifcvt_sequence (if_info
);
1167 emit_insn_before_setloc (seq
, if_info
->jump
,
1168 INSN_LOCATION (if_info
->insn_a
));
1178 /* Convert "if (test) x = a; else x = b", for A and B constant. */
1181 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
1186 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
1187 int normalize
, can_reverse
;
1190 if (CONST_INT_P (if_info
->a
)
1191 && CONST_INT_P (if_info
->b
))
1193 mode
= GET_MODE (if_info
->x
);
1194 ifalse
= INTVAL (if_info
->a
);
1195 itrue
= INTVAL (if_info
->b
);
1197 diff
= (unsigned HOST_WIDE_INT
) itrue
- ifalse
;
1198 /* Make sure we can represent the difference between the two values. */
1200 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
1203 diff
= trunc_int_for_mode (diff
, mode
);
1205 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1209 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1211 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
1212 && (STORE_FLAG_VALUE
== 1
1213 || if_info
->branch_cost
>= 2))
1215 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
1216 && (STORE_FLAG_VALUE
== 1 || if_info
->branch_cost
>= 2))
1217 normalize
= 1, reversep
= 1;
1218 else if (itrue
== -1
1219 && (STORE_FLAG_VALUE
== -1
1220 || if_info
->branch_cost
>= 2))
1222 else if (ifalse
== -1 && can_reverse
1223 && (STORE_FLAG_VALUE
== -1 || if_info
->branch_cost
>= 2))
1224 normalize
= -1, reversep
= 1;
1225 else if ((if_info
->branch_cost
>= 2 && STORE_FLAG_VALUE
== -1)
1226 || if_info
->branch_cost
>= 3)
1233 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
1234 diff
= trunc_int_for_mode (-(unsigned HOST_WIDE_INT
) diff
, mode
);
1238 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
1245 /* if (test) x = 3; else x = 4;
1246 => x = 3 + (test == 0); */
1247 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1249 target
= expand_simple_binop (mode
,
1250 (diff
== STORE_FLAG_VALUE
1252 gen_int_mode (ifalse
, mode
), target
,
1253 if_info
->x
, 0, OPTAB_WIDEN
);
1256 /* if (test) x = 8; else x = 0;
1257 => x = (test != 0) << 3; */
1258 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
1260 target
= expand_simple_binop (mode
, ASHIFT
,
1261 target
, GEN_INT (tmp
), if_info
->x
, 0,
1265 /* if (test) x = -1; else x = b;
1266 => x = -(test != 0) | b; */
1267 else if (itrue
== -1)
1269 target
= expand_simple_binop (mode
, IOR
,
1270 target
, gen_int_mode (ifalse
, mode
),
1271 if_info
->x
, 0, OPTAB_WIDEN
);
1274 /* if (test) x = a; else x = b;
1275 => x = (-(test != 0) & (b - a)) + a; */
1278 target
= expand_simple_binop (mode
, AND
,
1279 target
, gen_int_mode (diff
, mode
),
1280 if_info
->x
, 0, OPTAB_WIDEN
);
1282 target
= expand_simple_binop (mode
, PLUS
,
1283 target
, gen_int_mode (ifalse
, mode
),
1284 if_info
->x
, 0, OPTAB_WIDEN
);
1293 if (target
!= if_info
->x
)
1294 noce_emit_move_insn (if_info
->x
, target
);
1296 seq
= end_ifcvt_sequence (if_info
);
1300 emit_insn_before_setloc (seq
, if_info
->jump
,
1301 INSN_LOCATION (if_info
->insn_a
));
1308 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1309 similarly for "foo--". */
1312 noce_try_addcc (struct noce_if_info
*if_info
)
1316 int subtract
, normalize
;
1318 if (GET_CODE (if_info
->a
) == PLUS
1319 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1320 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1323 rtx cond
= if_info
->cond
;
1324 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1326 /* First try to use addcc pattern. */
1327 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1328 && general_operand (XEXP (cond
, 1), VOIDmode
))
1331 target
= emit_conditional_add (if_info
->x
, code
,
1336 XEXP (if_info
->a
, 1),
1337 GET_MODE (if_info
->x
),
1338 (code
== LTU
|| code
== GEU
1339 || code
== LEU
|| code
== GTU
));
1342 if (target
!= if_info
->x
)
1343 noce_emit_move_insn (if_info
->x
, target
);
1345 seq
= end_ifcvt_sequence (if_info
);
1349 emit_insn_before_setloc (seq
, if_info
->jump
,
1350 INSN_LOCATION (if_info
->insn_a
));
1356 /* If that fails, construct conditional increment or decrement using
1358 if (if_info
->branch_cost
>= 2
1359 && (XEXP (if_info
->a
, 1) == const1_rtx
1360 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1363 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1364 subtract
= 0, normalize
= 0;
1365 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1366 subtract
= 1, normalize
= 0;
1368 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1371 target
= noce_emit_store_flag (if_info
,
1372 gen_reg_rtx (GET_MODE (if_info
->x
)),
1376 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1377 subtract
? MINUS
: PLUS
,
1378 if_info
->b
, target
, if_info
->x
,
1382 if (target
!= if_info
->x
)
1383 noce_emit_move_insn (if_info
->x
, target
);
1385 seq
= end_ifcvt_sequence (if_info
);
1389 emit_insn_before_setloc (seq
, if_info
->jump
,
1390 INSN_LOCATION (if_info
->insn_a
));
1400 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1403 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1410 if ((if_info
->branch_cost
>= 2
1411 || STORE_FLAG_VALUE
== -1)
1412 && ((if_info
->a
== const0_rtx
1413 && rtx_equal_p (if_info
->b
, if_info
->x
))
1414 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1417 && if_info
->b
== const0_rtx
1418 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1421 target
= noce_emit_store_flag (if_info
,
1422 gen_reg_rtx (GET_MODE (if_info
->x
)),
1425 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1427 target
, if_info
->x
, 0,
1432 int old_cost
, new_cost
, insn_cost
;
1435 if (target
!= if_info
->x
)
1436 noce_emit_move_insn (if_info
->x
, target
);
1438 seq
= end_ifcvt_sequence (if_info
);
1442 speed_p
= optimize_bb_for_speed_p (BLOCK_FOR_INSN (if_info
->insn_a
));
1443 insn_cost
= insn_rtx_cost (PATTERN (if_info
->insn_a
), speed_p
);
1444 old_cost
= COSTS_N_INSNS (if_info
->branch_cost
) + insn_cost
;
1445 new_cost
= seq_cost (seq
, speed_p
);
1447 if (new_cost
> old_cost
)
1450 emit_insn_before_setloc (seq
, if_info
->jump
,
1451 INSN_LOCATION (if_info
->insn_a
));
1461 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1464 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1465 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1467 rtx target ATTRIBUTE_UNUSED
;
1468 int unsignedp ATTRIBUTE_UNUSED
;
1470 /* If earliest == jump, try to build the cmove insn directly.
1471 This is helpful when combine has created some complex condition
1472 (like for alpha's cmovlbs) that we can't hope to regenerate
1473 through the normal interface. */
1475 if (if_info
->cond_earliest
== if_info
->jump
)
1477 rtx cond
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1478 rtx if_then_else
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
),
1479 cond
, vtrue
, vfalse
);
1480 rtx set
= gen_rtx_SET (VOIDmode
, x
, if_then_else
);
1483 rtx_insn
*insn
= emit_insn (set
);
1485 if (recog_memoized (insn
) >= 0)
1487 rtx_insn
*seq
= get_insns ();
1497 /* Don't even try if the comparison operands are weird
1498 except that the target supports cbranchcc4. */
1499 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1500 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1502 if (!(HAVE_cbranchcc4
)
1503 || GET_MODE_CLASS (GET_MODE (cmp_a
)) != MODE_CC
1504 || cmp_b
!= const0_rtx
)
1508 #if HAVE_conditional_move
1509 unsignedp
= (code
== LTU
|| code
== GEU
1510 || code
== LEU
|| code
== GTU
);
1512 target
= emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1513 vtrue
, vfalse
, GET_MODE (x
),
1518 /* We might be faced with a situation like:
1521 vtrue = (subreg:M (reg:N VTRUE) BYTE)
1522 vfalse = (subreg:M (reg:N VFALSE) BYTE)
1524 We can't do a conditional move in mode M, but it's possible that we
1525 could do a conditional move in mode N instead and take a subreg of
1528 If we can't create new pseudos, though, don't bother. */
1529 if (reload_completed
)
1532 if (GET_CODE (vtrue
) == SUBREG
&& GET_CODE (vfalse
) == SUBREG
)
1534 rtx reg_vtrue
= SUBREG_REG (vtrue
);
1535 rtx reg_vfalse
= SUBREG_REG (vfalse
);
1536 unsigned int byte_vtrue
= SUBREG_BYTE (vtrue
);
1537 unsigned int byte_vfalse
= SUBREG_BYTE (vfalse
);
1538 rtx promoted_target
;
1540 if (GET_MODE (reg_vtrue
) != GET_MODE (reg_vfalse
)
1541 || byte_vtrue
!= byte_vfalse
1542 || (SUBREG_PROMOTED_VAR_P (vtrue
)
1543 != SUBREG_PROMOTED_VAR_P (vfalse
))
1544 || (SUBREG_PROMOTED_GET (vtrue
)
1545 != SUBREG_PROMOTED_GET (vfalse
)))
1548 promoted_target
= gen_reg_rtx (GET_MODE (reg_vtrue
));
1550 target
= emit_conditional_move (promoted_target
, code
, cmp_a
, cmp_b
,
1551 VOIDmode
, reg_vtrue
, reg_vfalse
,
1552 GET_MODE (reg_vtrue
), unsignedp
);
1553 /* Nope, couldn't do it in that mode either. */
1557 target
= gen_rtx_SUBREG (GET_MODE (vtrue
), promoted_target
, byte_vtrue
);
1558 SUBREG_PROMOTED_VAR_P (target
) = SUBREG_PROMOTED_VAR_P (vtrue
);
1559 SUBREG_PROMOTED_SET (target
, SUBREG_PROMOTED_GET (vtrue
));
1560 emit_move_insn (x
, target
);
1566 /* We'll never get here, as noce_process_if_block doesn't call the
1567 functions involved. Ifdef code, however, should be discouraged
1568 because it leads to typos in the code not selected. However,
1569 emit_conditional_move won't exist either. */
1574 /* Try only simple constants and registers here. More complex cases
1575 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1576 has had a go at it. */
1579 noce_try_cmove (struct noce_if_info
*if_info
)
1585 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1586 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1590 code
= GET_CODE (if_info
->cond
);
1591 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1592 XEXP (if_info
->cond
, 0),
1593 XEXP (if_info
->cond
, 1),
1594 if_info
->a
, if_info
->b
);
1598 if (target
!= if_info
->x
)
1599 noce_emit_move_insn (if_info
->x
, target
);
1601 seq
= end_ifcvt_sequence (if_info
);
1605 emit_insn_before_setloc (seq
, if_info
->jump
,
1606 INSN_LOCATION (if_info
->insn_a
));
1619 /* Try more complex cases involving conditional_move. */
1622 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1628 rtx_insn
*insn_a
, *insn_b
;
1633 rtx_insn
*ifcvt_seq
;
1635 /* A conditional move from two memory sources is equivalent to a
1636 conditional on their addresses followed by a load. Don't do this
1637 early because it'll screw alias analysis. Note that we've
1638 already checked for no side effects. */
1639 /* ??? FIXME: Magic number 5. */
1640 if (cse_not_expected
1641 && MEM_P (a
) && MEM_P (b
)
1642 && MEM_ADDR_SPACE (a
) == MEM_ADDR_SPACE (b
)
1643 && if_info
->branch_cost
>= 5)
1645 machine_mode address_mode
= get_address_mode (a
);
1649 x
= gen_reg_rtx (address_mode
);
1653 /* ??? We could handle this if we knew that a load from A or B could
1654 not trap or fault. This is also true if we've already loaded
1655 from the address along the path from ENTRY. */
1656 else if (may_trap_or_fault_p (a
) || may_trap_or_fault_p (b
))
1659 /* if (test) x = a + b; else x = c - d;
1666 code
= GET_CODE (if_info
->cond
);
1667 insn_a
= if_info
->insn_a
;
1668 insn_b
= if_info
->insn_b
;
1670 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1671 if insn_rtx_cost can't be estimated. */
1675 = insn_rtx_cost (PATTERN (insn_a
),
1676 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a
)));
1677 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1686 += insn_rtx_cost (PATTERN (insn_b
),
1687 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b
)));
1688 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1692 /* Possibly rearrange operands to make things come out more natural. */
1693 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1696 if (rtx_equal_p (b
, x
))
1698 else if (general_operand (b
, GET_MODE (b
)))
1705 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1706 tmp
= a
, a
= b
, b
= tmp
;
1707 tmp_insn
= insn_a
, insn_a
= insn_b
, insn_b
= tmp_insn
;
1716 /* If either operand is complex, load it into a register first.
1717 The best way to do this is to copy the original insn. In this
1718 way we preserve any clobbers etc that the insn may have had.
1719 This is of course not possible in the IS_MEM case. */
1720 if (! general_operand (a
, GET_MODE (a
)))
1726 rtx reg
= gen_reg_rtx (GET_MODE (a
));
1727 insn
= emit_insn (gen_rtx_SET (VOIDmode
, reg
, a
));
1730 goto end_seq_and_fail
;
1733 a
= gen_reg_rtx (GET_MODE (a
));
1734 rtx_insn
*copy_of_a
= as_a
<rtx_insn
*> (copy_rtx (insn_a
));
1735 rtx set
= single_set (copy_of_a
);
1737 insn
= emit_insn (PATTERN (copy_of_a
));
1739 if (recog_memoized (insn
) < 0)
1740 goto end_seq_and_fail
;
1742 if (! general_operand (b
, GET_MODE (b
)))
1750 rtx reg
= gen_reg_rtx (GET_MODE (b
));
1751 pat
= gen_rtx_SET (VOIDmode
, reg
, b
);
1754 goto end_seq_and_fail
;
1757 b
= gen_reg_rtx (GET_MODE (b
));
1758 rtx_insn
*copy_of_insn_b
= as_a
<rtx_insn
*> (copy_rtx (insn_b
));
1759 rtx set
= single_set (copy_of_insn_b
);
1761 pat
= PATTERN (copy_of_insn_b
);
1764 /* If insn to set up A clobbers any registers B depends on, try to
1765 swap insn that sets up A with the one that sets up B. If even
1766 that doesn't help, punt. */
1767 last
= get_last_insn ();
1768 if (last
&& modified_in_p (orig_b
, last
))
1770 new_insn
= emit_insn_before (pat
, get_insns ());
1771 if (modified_in_p (orig_a
, new_insn
))
1772 goto end_seq_and_fail
;
1775 new_insn
= emit_insn (pat
);
1777 if (recog_memoized (new_insn
) < 0)
1778 goto end_seq_and_fail
;
1781 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1782 XEXP (if_info
->cond
, 1), a
, b
);
1785 goto end_seq_and_fail
;
1787 /* If we're handling a memory for above, emit the load now. */
1790 rtx mem
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1792 /* Copy over flags as appropriate. */
1793 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1794 MEM_VOLATILE_P (mem
) = 1;
1795 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1796 set_mem_alias_set (mem
, MEM_ALIAS_SET (if_info
->a
));
1798 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1800 gcc_assert (MEM_ADDR_SPACE (if_info
->a
) == MEM_ADDR_SPACE (if_info
->b
));
1801 set_mem_addr_space (mem
, MEM_ADDR_SPACE (if_info
->a
));
1803 noce_emit_move_insn (if_info
->x
, mem
);
1805 else if (target
!= x
)
1806 noce_emit_move_insn (x
, target
);
1808 ifcvt_seq
= end_ifcvt_sequence (if_info
);
1812 emit_insn_before_setloc (ifcvt_seq
, if_info
->jump
,
1813 INSN_LOCATION (if_info
->insn_a
));
1821 /* For most cases, the simplified condition we found is the best
1822 choice, but this is not the case for the min/max/abs transforms.
1823 For these we wish to know that it is A or B in the condition. */
1826 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1827 rtx_insn
**earliest
)
1833 /* If target is already mentioned in the known condition, return it. */
1834 if (reg_mentioned_p (target
, if_info
->cond
))
1836 *earliest
= if_info
->cond_earliest
;
1837 return if_info
->cond
;
1840 set
= pc_set (if_info
->jump
);
1841 cond
= XEXP (SET_SRC (set
), 0);
1843 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1844 && LABEL_REF_LABEL (XEXP (SET_SRC (set
), 2)) == JUMP_LABEL (if_info
->jump
);
1845 if (if_info
->then_else_reversed
)
1848 /* If we're looking for a constant, try to make the conditional
1849 have that constant in it. There are two reasons why it may
1850 not have the constant we want:
1852 1. GCC may have needed to put the constant in a register, because
1853 the target can't compare directly against that constant. For
1854 this case, we look for a SET immediately before the comparison
1855 that puts a constant in that register.
1857 2. GCC may have canonicalized the conditional, for example
1858 replacing "if x < 4" with "if x <= 3". We can undo that (or
1859 make equivalent types of changes) to get the constants we need
1860 if they're off by one in the right direction. */
1862 if (CONST_INT_P (target
))
1864 enum rtx_code code
= GET_CODE (if_info
->cond
);
1865 rtx op_a
= XEXP (if_info
->cond
, 0);
1866 rtx op_b
= XEXP (if_info
->cond
, 1);
1869 /* First, look to see if we put a constant in a register. */
1870 prev_insn
= prev_nonnote_insn (if_info
->cond_earliest
);
1872 && BLOCK_FOR_INSN (prev_insn
)
1873 == BLOCK_FOR_INSN (if_info
->cond_earliest
)
1874 && INSN_P (prev_insn
)
1875 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1877 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1879 src
= SET_SRC (PATTERN (prev_insn
));
1880 if (CONST_INT_P (src
))
1882 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1884 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1887 if (CONST_INT_P (op_a
))
1892 code
= swap_condition (code
);
1897 /* Now, look to see if we can get the right constant by
1898 adjusting the conditional. */
1899 if (CONST_INT_P (op_b
))
1901 HOST_WIDE_INT desired_val
= INTVAL (target
);
1902 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1907 if (actual_val
== desired_val
+ 1)
1910 op_b
= GEN_INT (desired_val
);
1914 if (actual_val
== desired_val
- 1)
1917 op_b
= GEN_INT (desired_val
);
1921 if (actual_val
== desired_val
- 1)
1924 op_b
= GEN_INT (desired_val
);
1928 if (actual_val
== desired_val
+ 1)
1931 op_b
= GEN_INT (desired_val
);
1939 /* If we made any changes, generate a new conditional that is
1940 equivalent to what we started with, but has the right
1942 if (code
!= GET_CODE (if_info
->cond
)
1943 || op_a
!= XEXP (if_info
->cond
, 0)
1944 || op_b
!= XEXP (if_info
->cond
, 1))
1946 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1947 *earliest
= if_info
->cond_earliest
;
1952 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1953 earliest
, target
, HAVE_cbranchcc4
, true);
1954 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1957 /* We almost certainly searched back to a different place.
1958 Need to re-verify correct lifetimes. */
1960 /* X may not be mentioned in the range (cond_earliest, jump]. */
1961 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1962 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1965 /* A and B may not be modified in the range [cond_earliest, jump). */
1966 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1968 && (modified_in_p (if_info
->a
, insn
)
1969 || modified_in_p (if_info
->b
, insn
)))
1975 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1978 noce_try_minmax (struct noce_if_info
*if_info
)
1981 rtx_insn
*earliest
, *seq
;
1982 enum rtx_code code
, op
;
1985 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1986 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1987 to get the target to tell us... */
1988 if (HONOR_SIGNED_ZEROS (if_info
->x
)
1989 || HONOR_NANS (if_info
->x
))
1992 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1996 /* Verify the condition is of the form we expect, and canonicalize
1997 the comparison code. */
1998 code
= GET_CODE (cond
);
1999 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
2001 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
2004 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
2006 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
2008 code
= swap_condition (code
);
2013 /* Determine what sort of operation this is. Note that the code is for
2014 a taken branch, so the code->operation mapping appears backwards. */
2047 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
2048 if_info
->a
, if_info
->b
,
2049 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
2055 if (target
!= if_info
->x
)
2056 noce_emit_move_insn (if_info
->x
, target
);
2058 seq
= end_ifcvt_sequence (if_info
);
2062 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2063 if_info
->cond
= cond
;
2064 if_info
->cond_earliest
= earliest
;
2069 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
2070 "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
2074 noce_try_abs (struct noce_if_info
*if_info
)
2076 rtx cond
, target
, a
, b
, c
;
2077 rtx_insn
*earliest
, *seq
;
2079 bool one_cmpl
= false;
2081 /* Reject modes with signed zeros. */
2082 if (HONOR_SIGNED_ZEROS (if_info
->x
))
2085 /* Recognize A and B as constituting an ABS or NABS. The canonical
2086 form is a branch around the negation, taken when the object is the
2087 first operand of a comparison against 0 that evaluates to true. */
2090 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
2092 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
2094 c
= a
; a
= b
; b
= c
;
2097 else if (GET_CODE (a
) == NOT
&& rtx_equal_p (XEXP (a
, 0), b
))
2102 else if (GET_CODE (b
) == NOT
&& rtx_equal_p (XEXP (b
, 0), a
))
2104 c
= a
; a
= b
; b
= c
;
2111 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
2115 /* Verify the condition is of the form we expect. */
2116 if (rtx_equal_p (XEXP (cond
, 0), b
))
2118 else if (rtx_equal_p (XEXP (cond
, 1), b
))
2126 /* Verify that C is zero. Search one step backward for a
2127 REG_EQUAL note or a simple source if necessary. */
2131 rtx_insn
*insn
= prev_nonnote_insn (earliest
);
2133 && BLOCK_FOR_INSN (insn
) == BLOCK_FOR_INSN (earliest
)
2134 && (set
= single_set (insn
))
2135 && rtx_equal_p (SET_DEST (set
), c
))
2137 rtx note
= find_reg_equal_equiv_note (insn
);
2147 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
2148 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
2149 c
= get_pool_constant (XEXP (c
, 0));
2151 /* Work around funny ideas get_condition has wrt canonicalization.
2152 Note that these rtx constants are known to be CONST_INT, and
2153 therefore imply integer comparisons.
2154 The one_cmpl case is more complicated, as we want to handle
2155 only x < 0 ? ~x : x or x >= 0 ? x : ~x to one_cmpl_abs (x)
2156 and x < 0 ? x : ~x or x >= 0 ? ~x : x to ~one_cmpl_abs (x),
2157 but not other cases (x > -1 is equivalent of x >= 0). */
2158 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
2160 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
2165 else if (c
== CONST0_RTX (GET_MODE (b
)))
2168 && GET_CODE (cond
) != GE
2169 && GET_CODE (cond
) != LT
)
2175 /* Determine what sort of operation this is. */
2176 switch (GET_CODE (cond
))
2195 target
= expand_one_cmpl_abs_nojump (GET_MODE (if_info
->x
), b
,
2198 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
2200 /* ??? It's a quandary whether cmove would be better here, especially
2201 for integers. Perhaps combine will clean things up. */
2202 if (target
&& negate
)
2205 target
= expand_simple_unop (GET_MODE (target
), NOT
, target
,
2208 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
,
2218 if (target
!= if_info
->x
)
2219 noce_emit_move_insn (if_info
->x
, target
);
2221 seq
= end_ifcvt_sequence (if_info
);
2225 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2226 if_info
->cond
= cond
;
2227 if_info
->cond_earliest
= earliest
;
2232 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
2235 noce_try_sign_mask (struct noce_if_info
*if_info
)
2241 bool t_unconditional
;
2243 cond
= if_info
->cond
;
2244 code
= GET_CODE (cond
);
2249 if (if_info
->a
== const0_rtx
)
2251 if ((code
== LT
&& c
== const0_rtx
)
2252 || (code
== LE
&& c
== constm1_rtx
))
2255 else if (if_info
->b
== const0_rtx
)
2257 if ((code
== GE
&& c
== const0_rtx
)
2258 || (code
== GT
&& c
== constm1_rtx
))
2262 if (! t
|| side_effects_p (t
))
2265 /* We currently don't handle different modes. */
2266 mode
= GET_MODE (t
);
2267 if (GET_MODE (m
) != mode
)
2270 /* This is only profitable if T is unconditionally executed/evaluated in the
2271 original insn sequence or T is cheap. The former happens if B is the
2272 non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
2273 INSN_B which can happen for e.g. conditional stores to memory. For the
2274 cost computation use the block TEST_BB where the evaluation will end up
2275 after the transformation. */
2278 && (if_info
->insn_b
== NULL_RTX
2279 || BLOCK_FOR_INSN (if_info
->insn_b
) == if_info
->test_bb
));
2280 if (!(t_unconditional
2281 || (set_src_cost (t
, optimize_bb_for_speed_p (if_info
->test_bb
))
2282 < COSTS_N_INSNS (2))))
2286 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
2287 "(signed) m >> 31" directly. This benefits targets with specialized
2288 insns to obtain the signmask, but still uses ashr_optab otherwise. */
2289 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
2290 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
2299 noce_emit_move_insn (if_info
->x
, t
);
2301 seq
= end_ifcvt_sequence (if_info
);
2305 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2310 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
2314 noce_try_bitop (struct noce_if_info
*if_info
)
2316 rtx cond
, x
, a
, result
;
2323 cond
= if_info
->cond
;
2324 code
= GET_CODE (cond
);
2326 /* Check for no else condition. */
2327 if (! rtx_equal_p (x
, if_info
->b
))
2330 /* Check for a suitable condition. */
2331 if (code
!= NE
&& code
!= EQ
)
2333 if (XEXP (cond
, 1) != const0_rtx
)
2335 cond
= XEXP (cond
, 0);
2337 /* ??? We could also handle AND here. */
2338 if (GET_CODE (cond
) == ZERO_EXTRACT
)
2340 if (XEXP (cond
, 1) != const1_rtx
2341 || !CONST_INT_P (XEXP (cond
, 2))
2342 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
2344 bitnum
= INTVAL (XEXP (cond
, 2));
2345 mode
= GET_MODE (x
);
2346 if (BITS_BIG_ENDIAN
)
2347 bitnum
= GET_MODE_BITSIZE (mode
) - 1 - bitnum
;
2348 if (bitnum
< 0 || bitnum
>= HOST_BITS_PER_WIDE_INT
)
2355 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
2357 /* Check for "if (X & C) x = x op C". */
2358 if (! rtx_equal_p (x
, XEXP (a
, 0))
2359 || !CONST_INT_P (XEXP (a
, 1))
2360 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2361 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
2364 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
2365 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
2366 if (GET_CODE (a
) == IOR
)
2367 result
= (code
== NE
) ? a
: NULL_RTX
;
2368 else if (code
== NE
)
2370 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
2371 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
2372 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
2376 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2377 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
2378 result
= simplify_gen_binary (AND
, mode
, x
, result
);
2381 else if (GET_CODE (a
) == AND
)
2383 /* Check for "if (X & C) x &= ~C". */
2384 if (! rtx_equal_p (x
, XEXP (a
, 0))
2385 || !CONST_INT_P (XEXP (a
, 1))
2386 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2387 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
2390 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2391 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2392 result
= (code
== EQ
) ? a
: NULL_RTX
;
2400 noce_emit_move_insn (x
, result
);
2401 seq
= end_ifcvt_sequence (if_info
);
2405 emit_insn_before_setloc (seq
, if_info
->jump
,
2406 INSN_LOCATION (if_info
->insn_a
));
2412 /* Similar to get_condition, only the resulting condition must be
2413 valid at JUMP, instead of at EARLIEST.
2415 If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
2416 THEN block of the caller, and we have to reverse the condition. */
2419 noce_get_condition (rtx_insn
*jump
, rtx_insn
**earliest
, bool then_else_reversed
)
2424 if (! any_condjump_p (jump
))
2427 set
= pc_set (jump
);
2429 /* If this branches to JUMP_LABEL when the condition is false,
2430 reverse the condition. */
2431 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
2432 && LABEL_REF_LABEL (XEXP (SET_SRC (set
), 2)) == JUMP_LABEL (jump
));
2434 /* We may have to reverse because the caller's if block is not canonical,
2435 i.e. the THEN block isn't the fallthrough block for the TEST block
2436 (see find_if_header). */
2437 if (then_else_reversed
)
2440 /* If the condition variable is a register and is MODE_INT, accept it. */
2442 cond
= XEXP (SET_SRC (set
), 0);
2443 tmp
= XEXP (cond
, 0);
2444 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
2445 && (GET_MODE (tmp
) != BImode
2446 || !targetm
.small_register_classes_for_mode_p (BImode
)))
2451 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
2452 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2456 /* Otherwise, fall back on canonicalize_condition to do the dirty
2457 work of manipulating MODE_CC values and COMPARE rtx codes. */
2458 tmp
= canonicalize_condition (jump
, cond
, reverse
, earliest
,
2459 NULL_RTX
, HAVE_cbranchcc4
, true);
2461 /* We don't handle side-effects in the condition, like handling
2462 REG_INC notes and making sure no duplicate conditions are emitted. */
2463 if (tmp
!= NULL_RTX
&& side_effects_p (tmp
))
2469 /* Return true if OP is ok for if-then-else processing. */
2472 noce_operand_ok (const_rtx op
)
2474 if (side_effects_p (op
))
2477 /* We special-case memories, so handle any of them with
2478 no address side effects. */
2480 return ! side_effects_p (XEXP (op
, 0));
2482 return ! may_trap_p (op
);
2485 /* Return true if a write into MEM may trap or fault. */
2488 noce_mem_write_may_trap_or_fault_p (const_rtx mem
)
2492 if (MEM_READONLY_P (mem
))
2495 if (may_trap_or_fault_p (mem
))
2498 addr
= XEXP (mem
, 0);
2500 /* Call target hook to avoid the effects of -fpic etc.... */
2501 addr
= targetm
.delegitimize_address (addr
);
2504 switch (GET_CODE (addr
))
2512 addr
= XEXP (addr
, 0);
2516 addr
= XEXP (addr
, 1);
2519 if (CONST_INT_P (XEXP (addr
, 1)))
2520 addr
= XEXP (addr
, 0);
2527 if (SYMBOL_REF_DECL (addr
)
2528 && decl_readonly_section (SYMBOL_REF_DECL (addr
), 0))
2538 /* Return whether we can use store speculation for MEM. TOP_BB is the
2539 basic block above the conditional block where we are considering
2540 doing the speculative store. We look for whether MEM is set
2541 unconditionally later in the function. */
2544 noce_can_store_speculate_p (basic_block top_bb
, const_rtx mem
)
2546 basic_block dominator
;
2548 for (dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, top_bb
);
2550 dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, dominator
))
2554 FOR_BB_INSNS (dominator
, insn
)
2556 /* If we see something that might be a memory barrier, we
2557 have to stop looking. Even if the MEM is set later in
2558 the function, we still don't want to set it
2559 unconditionally before the barrier. */
2561 && (volatile_insn_p (PATTERN (insn
))
2562 || (CALL_P (insn
) && (!RTL_CONST_CALL_P (insn
)))))
2565 if (memory_must_be_modified_in_insn_p (mem
, insn
))
2567 if (modified_in_p (XEXP (mem
, 0), insn
))
2576 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2577 it without using conditional execution. Return TRUE if we were successful
2578 at converting the block. */
2581 noce_process_if_block (struct noce_if_info
*if_info
)
2583 basic_block test_bb
= if_info
->test_bb
; /* test block */
2584 basic_block then_bb
= if_info
->then_bb
; /* THEN */
2585 basic_block else_bb
= if_info
->else_bb
; /* ELSE or NULL */
2586 basic_block join_bb
= if_info
->join_bb
; /* JOIN */
2587 rtx_insn
*jump
= if_info
->jump
;
2588 rtx cond
= if_info
->cond
;
2589 rtx_insn
*insn_a
, *insn_b
;
2591 rtx orig_x
, x
, a
, b
;
2594 /* We're looking for patterns of the form
2596 (1) if (...) x = a; else x = b;
2597 (2) x = b; if (...) x = a;
2598 (3) if (...) x = a; // as if with an initial x = x.
2600 The later patterns require jumps to be more expensive.
2602 ??? For future expansion, look for multiple X in such patterns. */
2604 /* Look for one of the potential sets. */
2605 insn_a
= first_active_insn (then_bb
);
2607 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2608 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2611 x
= SET_DEST (set_a
);
2612 a
= SET_SRC (set_a
);
2614 /* Look for the other potential set. Make sure we've got equivalent
2616 /* ??? This is overconservative. Storing to two different mems is
2617 as easy as conditionally computing the address. Storing to a
2618 single mem merely requires a scratch memory to use as one of the
2619 destination addresses; often the memory immediately below the
2620 stack pointer is available for this. */
2624 insn_b
= first_active_insn (else_bb
);
2626 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2627 || (set_b
= single_set (insn_b
)) == NULL_RTX
2628 || ! rtx_interchangeable_p (x
, SET_DEST (set_b
)))
2633 insn_b
= prev_nonnote_nondebug_insn (if_info
->cond_earliest
);
2634 /* We're going to be moving the evaluation of B down from above
2635 COND_EARLIEST to JUMP. Make sure the relevant data is still
2638 || BLOCK_FOR_INSN (insn_b
) != BLOCK_FOR_INSN (if_info
->cond_earliest
)
2639 || !NONJUMP_INSN_P (insn_b
)
2640 || (set_b
= single_set (insn_b
)) == NULL_RTX
2641 || ! rtx_interchangeable_p (x
, SET_DEST (set_b
))
2642 || ! noce_operand_ok (SET_SRC (set_b
))
2643 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2644 || modified_between_p (SET_SRC (set_b
), insn_b
, jump
)
2645 /* Avoid extending the lifetime of hard registers on small
2646 register class machines. */
2647 || (REG_P (SET_SRC (set_b
))
2648 && HARD_REGISTER_P (SET_SRC (set_b
))
2649 && targetm
.small_register_classes_for_mode_p
2650 (GET_MODE (SET_SRC (set_b
))))
2651 /* Likewise with X. In particular this can happen when
2652 noce_get_condition looks farther back in the instruction
2653 stream than one might expect. */
2654 || reg_overlap_mentioned_p (x
, cond
)
2655 || reg_overlap_mentioned_p (x
, a
)
2656 || modified_between_p (x
, insn_b
, jump
))
2663 /* If x has side effects then only the if-then-else form is safe to
2664 convert. But even in that case we would need to restore any notes
2665 (such as REG_INC) at then end. That can be tricky if
2666 noce_emit_move_insn expands to more than one insn, so disable the
2667 optimization entirely for now if there are side effects. */
2668 if (side_effects_p (x
))
2671 b
= (set_b
? SET_SRC (set_b
) : x
);
2673 /* Only operate on register destinations, and even then avoid extending
2674 the lifetime of hard registers on small register class machines. */
2677 || (HARD_REGISTER_P (x
)
2678 && targetm
.small_register_classes_for_mode_p (GET_MODE (x
))))
2680 if (GET_MODE (x
) == BLKmode
)
2683 if (GET_CODE (x
) == ZERO_EXTRACT
2684 && (!CONST_INT_P (XEXP (x
, 1))
2685 || !CONST_INT_P (XEXP (x
, 2))))
2688 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2689 ? XEXP (x
, 0) : x
));
2692 /* Don't operate on sources that may trap or are volatile. */
2693 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2697 /* Set up the info block for our subroutines. */
2698 if_info
->insn_a
= insn_a
;
2699 if_info
->insn_b
= insn_b
;
2704 /* Skip it if the instruction to be moved might clobber CC. */
2705 cc
= cc_in_cond (cond
);
2707 && (set_of (cc
, insn_a
)
2708 || (insn_b
&& set_of (cc
, insn_b
))))
2711 /* Try optimizations in some approximation of a useful order. */
2712 /* ??? Should first look to see if X is live incoming at all. If it
2713 isn't, we don't need anything but an unconditional set. */
2715 /* Look and see if A and B are really the same. Avoid creating silly
2716 cmove constructs that no one will fix up later. */
2717 if (rtx_interchangeable_p (a
, b
))
2719 /* If we have an INSN_B, we don't have to create any new rtl. Just
2720 move the instruction that we already have. If we don't have an
2721 INSN_B, that means that A == X, and we've got a noop move. In
2722 that case don't do anything and let the code below delete INSN_A. */
2723 if (insn_b
&& else_bb
)
2727 if (else_bb
&& insn_b
== BB_END (else_bb
))
2728 BB_END (else_bb
) = PREV_INSN (insn_b
);
2729 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2731 /* If there was a REG_EQUAL note, delete it since it may have been
2732 true due to this insn being after a jump. */
2733 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2734 remove_note (insn_b
, note
);
2738 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2739 x must be executed twice. */
2740 else if (insn_b
&& side_effects_p (orig_x
))
2747 if (!set_b
&& MEM_P (orig_x
))
2749 /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
2750 for optimizations if writing to x may trap or fault,
2751 i.e. it's a memory other than a static var or a stack slot,
2752 is misaligned on strict aligned machines or is read-only. If
2753 x is a read-only memory, then the program is valid only if we
2754 avoid the store into it. If there are stores on both the
2755 THEN and ELSE arms, then we can go ahead with the conversion;
2756 either the program is broken, or the condition is always
2757 false such that the other memory is selected. */
2758 if (noce_mem_write_may_trap_or_fault_p (orig_x
))
2761 /* Avoid store speculation: given "if (...) x = a" where x is a
2762 MEM, we only want to do the store if x is always set
2763 somewhere in the function. This avoids cases like
2764 if (pthread_mutex_trylock(mutex))
2766 where we only want global_variable to be changed if the mutex
2767 is held. FIXME: This should ideally be expressed directly in
2769 if (!noce_can_store_speculate_p (test_bb
, orig_x
))
2773 if (noce_try_move (if_info
))
2775 if (noce_try_store_flag (if_info
))
2777 if (noce_try_bitop (if_info
))
2779 if (noce_try_minmax (if_info
))
2781 if (noce_try_abs (if_info
))
2783 if (HAVE_conditional_move
2784 && noce_try_cmove (if_info
))
2786 if (! targetm
.have_conditional_execution ())
2788 if (noce_try_store_flag_constants (if_info
))
2790 if (noce_try_addcc (if_info
))
2792 if (noce_try_store_flag_mask (if_info
))
2794 if (HAVE_conditional_move
2795 && noce_try_cmove_arith (if_info
))
2797 if (noce_try_sign_mask (if_info
))
2801 if (!else_bb
&& set_b
)
2813 /* If we used a temporary, fix it up now. */
2819 noce_emit_move_insn (orig_x
, x
);
2821 set_used_flags (orig_x
);
2822 unshare_all_rtl_in_chain (seq
);
2825 emit_insn_before_setloc (seq
, BB_END (test_bb
), INSN_LOCATION (insn_a
));
2828 /* The original THEN and ELSE blocks may now be removed. The test block
2829 must now jump to the join block. If the test block and the join block
2830 can be merged, do so. */
2833 delete_basic_block (else_bb
);
2837 remove_edge (find_edge (test_bb
, join_bb
));
2839 remove_edge (find_edge (then_bb
, join_bb
));
2840 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2841 delete_basic_block (then_bb
);
2844 if (can_merge_blocks_p (test_bb
, join_bb
))
2846 merge_blocks (test_bb
, join_bb
);
2850 num_updated_if_blocks
++;
2854 /* Check whether a block is suitable for conditional move conversion.
2855 Every insn must be a simple set of a register to a constant or a
2856 register. For each assignment, store the value in the pointer map
2857 VALS, keyed indexed by register pointer, then store the register
2858 pointer in REGS. COND is the condition we will test. */
2861 check_cond_move_block (basic_block bb
,
2862 hash_map
<rtx
, rtx
> *vals
,
2867 rtx cc
= cc_in_cond (cond
);
2869 /* We can only handle simple jumps at the end of the basic block.
2870 It is almost impossible to update the CFG otherwise. */
2872 if (JUMP_P (insn
) && !onlyjump_p (insn
))
2875 FOR_BB_INSNS (bb
, insn
)
2879 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2881 set
= single_set (insn
);
2885 dest
= SET_DEST (set
);
2886 src
= SET_SRC (set
);
2888 || (HARD_REGISTER_P (dest
)
2889 && targetm
.small_register_classes_for_mode_p (GET_MODE (dest
))))
2892 if (!CONSTANT_P (src
) && !register_operand (src
, VOIDmode
))
2895 if (side_effects_p (src
) || side_effects_p (dest
))
2898 if (may_trap_p (src
) || may_trap_p (dest
))
2901 /* Don't try to handle this if the source register was
2902 modified earlier in the block. */
2905 || (GET_CODE (src
) == SUBREG
&& REG_P (SUBREG_REG (src
))
2906 && vals
->get (SUBREG_REG (src
))))
2909 /* Don't try to handle this if the destination register was
2910 modified earlier in the block. */
2911 if (vals
->get (dest
))
2914 /* Don't try to handle this if the condition uses the
2915 destination register. */
2916 if (reg_overlap_mentioned_p (dest
, cond
))
2919 /* Don't try to handle this if the source register is modified
2920 later in the block. */
2921 if (!CONSTANT_P (src
)
2922 && modified_between_p (src
, insn
, NEXT_INSN (BB_END (bb
))))
2925 /* Skip it if the instruction to be moved might clobber CC. */
2926 if (cc
&& set_of (cc
, insn
))
2929 vals
->put (dest
, src
);
2931 regs
->safe_push (dest
);
2937 /* Given a basic block BB suitable for conditional move conversion,
2938 a condition COND, and pointer maps THEN_VALS and ELSE_VALS containing
2939 the register values depending on COND, emit the insns in the block as
2940 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2941 processed. The caller has started a sequence for the conversion.
2942 Return true if successful, false if something goes wrong. */
2945 cond_move_convert_if_block (struct noce_if_info
*if_infop
,
2946 basic_block bb
, rtx cond
,
2947 hash_map
<rtx
, rtx
> *then_vals
,
2948 hash_map
<rtx
, rtx
> *else_vals
,
2953 rtx cond_arg0
, cond_arg1
;
2955 code
= GET_CODE (cond
);
2956 cond_arg0
= XEXP (cond
, 0);
2957 cond_arg1
= XEXP (cond
, 1);
2959 FOR_BB_INSNS (bb
, insn
)
2961 rtx set
, target
, dest
, t
, e
;
2963 /* ??? Maybe emit conditional debug insn? */
2964 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2966 set
= single_set (insn
);
2967 gcc_assert (set
&& REG_P (SET_DEST (set
)));
2969 dest
= SET_DEST (set
);
2971 rtx
*then_slot
= then_vals
->get (dest
);
2972 rtx
*else_slot
= else_vals
->get (dest
);
2973 t
= then_slot
? *then_slot
: NULL_RTX
;
2974 e
= else_slot
? *else_slot
: NULL_RTX
;
2978 /* If this register was set in the then block, we already
2979 handled this case there. */
2992 target
= noce_emit_cmove (if_infop
, dest
, code
, cond_arg0
, cond_arg1
,
2998 noce_emit_move_insn (dest
, target
);
3004 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
3005 it using only conditional moves. Return TRUE if we were successful at
3006 converting the block. */
3009 cond_move_process_if_block (struct noce_if_info
*if_info
)
3011 basic_block test_bb
= if_info
->test_bb
;
3012 basic_block then_bb
= if_info
->then_bb
;
3013 basic_block else_bb
= if_info
->else_bb
;
3014 basic_block join_bb
= if_info
->join_bb
;
3015 rtx_insn
*jump
= if_info
->jump
;
3016 rtx cond
= if_info
->cond
;
3017 rtx_insn
*seq
, *loc_insn
;
3020 vec
<rtx
> then_regs
= vNULL
;
3021 vec
<rtx
> else_regs
= vNULL
;
3023 int success_p
= FALSE
;
3025 /* Build a mapping for each block to the value used for each
3027 hash_map
<rtx
, rtx
> then_vals
;
3028 hash_map
<rtx
, rtx
> else_vals
;
3030 /* Make sure the blocks are suitable. */
3031 if (!check_cond_move_block (then_bb
, &then_vals
, &then_regs
, cond
)
3033 && !check_cond_move_block (else_bb
, &else_vals
, &else_regs
, cond
)))
3036 /* Make sure the blocks can be used together. If the same register
3037 is set in both blocks, and is not set to a constant in both
3038 cases, then both blocks must set it to the same register. We
3039 have already verified that if it is set to a register, that the
3040 source register does not change after the assignment. Also count
3041 the number of registers set in only one of the blocks. */
3043 FOR_EACH_VEC_ELT (then_regs
, i
, reg
)
3045 rtx
*then_slot
= then_vals
.get (reg
);
3046 rtx
*else_slot
= else_vals
.get (reg
);
3048 gcc_checking_assert (then_slot
);
3053 rtx then_val
= *then_slot
;
3054 rtx else_val
= *else_slot
;
3055 if (!CONSTANT_P (then_val
) && !CONSTANT_P (else_val
)
3056 && !rtx_equal_p (then_val
, else_val
))
3061 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
3062 FOR_EACH_VEC_ELT (else_regs
, i
, reg
)
3064 gcc_checking_assert (else_vals
.get (reg
));
3065 if (!then_vals
.get (reg
))
3069 /* Make sure it is reasonable to convert this block. What matters
3070 is the number of assignments currently made in only one of the
3071 branches, since if we convert we are going to always execute
3073 if (c
> MAX_CONDITIONAL_EXECUTE
)
3076 /* Try to emit the conditional moves. First do the then block,
3077 then do anything left in the else blocks. */
3079 if (!cond_move_convert_if_block (if_info
, then_bb
, cond
,
3080 &then_vals
, &else_vals
, false)
3082 && !cond_move_convert_if_block (if_info
, else_bb
, cond
,
3083 &then_vals
, &else_vals
, true)))
3088 seq
= end_ifcvt_sequence (if_info
);
3092 loc_insn
= first_active_insn (then_bb
);
3095 loc_insn
= first_active_insn (else_bb
);
3096 gcc_assert (loc_insn
);
3098 emit_insn_before_setloc (seq
, jump
, INSN_LOCATION (loc_insn
));
3102 delete_basic_block (else_bb
);
3106 remove_edge (find_edge (test_bb
, join_bb
));
3108 remove_edge (find_edge (then_bb
, join_bb
));
3109 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
3110 delete_basic_block (then_bb
);
3113 if (can_merge_blocks_p (test_bb
, join_bb
))
3115 merge_blocks (test_bb
, join_bb
);
3119 num_updated_if_blocks
++;
3124 then_regs
.release ();
3125 else_regs
.release ();
3130 /* Determine if a given basic block heads a simple IF-THEN-JOIN or an
3131 IF-THEN-ELSE-JOIN block.
3133 If so, we'll try to convert the insns to not require the branch,
3134 using only transformations that do not require conditional execution.
3136 Return TRUE if we were successful at converting the block. */
3139 noce_find_if_block (basic_block test_bb
, edge then_edge
, edge else_edge
,
3142 basic_block then_bb
, else_bb
, join_bb
;
3143 bool then_else_reversed
= false;
3146 rtx_insn
*cond_earliest
;
3147 struct noce_if_info if_info
;
3149 /* We only ever should get here before reload. */
3150 gcc_assert (!reload_completed
);
3152 /* Recognize an IF-THEN-ELSE-JOIN block. */
3153 if (single_pred_p (then_edge
->dest
)
3154 && single_succ_p (then_edge
->dest
)
3155 && single_pred_p (else_edge
->dest
)
3156 && single_succ_p (else_edge
->dest
)
3157 && single_succ (then_edge
->dest
) == single_succ (else_edge
->dest
))
3159 then_bb
= then_edge
->dest
;
3160 else_bb
= else_edge
->dest
;
3161 join_bb
= single_succ (then_bb
);
3163 /* Recognize an IF-THEN-JOIN block. */
3164 else if (single_pred_p (then_edge
->dest
)
3165 && single_succ_p (then_edge
->dest
)
3166 && single_succ (then_edge
->dest
) == else_edge
->dest
)
3168 then_bb
= then_edge
->dest
;
3169 else_bb
= NULL_BLOCK
;
3170 join_bb
= else_edge
->dest
;
3172 /* Recognize an IF-ELSE-JOIN block. We can have those because the order
3173 of basic blocks in cfglayout mode does not matter, so the fallthrough
3174 edge can go to any basic block (and not just to bb->next_bb, like in
3176 else if (single_pred_p (else_edge
->dest
)
3177 && single_succ_p (else_edge
->dest
)
3178 && single_succ (else_edge
->dest
) == then_edge
->dest
)
3180 /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
3181 To make this work, we have to invert the THEN and ELSE blocks
3182 and reverse the jump condition. */
3183 then_bb
= else_edge
->dest
;
3184 else_bb
= NULL_BLOCK
;
3185 join_bb
= single_succ (then_bb
);
3186 then_else_reversed
= true;
3189 /* Not a form we can handle. */
3192 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3193 if (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3196 && single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3199 num_possible_if_blocks
++;
3204 "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
3205 (else_bb
) ? "-ELSE" : "",
3206 pass
, test_bb
->index
, then_bb
->index
);
3209 fprintf (dump_file
, ", else %d", else_bb
->index
);
3211 fprintf (dump_file
, ", join %d\n", join_bb
->index
);
3214 /* If the conditional jump is more than just a conditional
3215 jump, then we can not do if-conversion on this block. */
3216 jump
= BB_END (test_bb
);
3217 if (! onlyjump_p (jump
))
3220 /* If this is not a standard conditional jump, we can't parse it. */
3221 cond
= noce_get_condition (jump
, &cond_earliest
, then_else_reversed
);
3225 /* We must be comparing objects whose modes imply the size. */
3226 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3229 /* Initialize an IF_INFO struct to pass around. */
3230 memset (&if_info
, 0, sizeof if_info
);
3231 if_info
.test_bb
= test_bb
;
3232 if_info
.then_bb
= then_bb
;
3233 if_info
.else_bb
= else_bb
;
3234 if_info
.join_bb
= join_bb
;
3235 if_info
.cond
= cond
;
3236 if_info
.cond_earliest
= cond_earliest
;
3237 if_info
.jump
= jump
;
3238 if_info
.then_else_reversed
= then_else_reversed
;
3239 if_info
.branch_cost
= BRANCH_COST (optimize_bb_for_speed_p (test_bb
),
3240 predictable_edge_p (then_edge
));
3242 /* Do the real work. */
3244 if (noce_process_if_block (&if_info
))
3247 if (HAVE_conditional_move
3248 && cond_move_process_if_block (&if_info
))
3255 /* Merge the blocks and mark for local life update. */
3258 merge_if_block (struct ce_if_block
* ce_info
)
3260 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
3261 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
3262 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
3263 basic_block join_bb
= ce_info
->join_bb
; /* join block */
3264 basic_block combo_bb
;
3266 /* All block merging is done into the lower block numbers. */
3269 df_set_bb_dirty (test_bb
);
3271 /* Merge any basic blocks to handle && and || subtests. Each of
3272 the blocks are on the fallthru path from the predecessor block. */
3273 if (ce_info
->num_multiple_test_blocks
> 0)
3275 basic_block bb
= test_bb
;
3276 basic_block last_test_bb
= ce_info
->last_test_bb
;
3277 basic_block fallthru
= block_fallthru (bb
);
3282 fallthru
= block_fallthru (bb
);
3283 merge_blocks (combo_bb
, bb
);
3286 while (bb
!= last_test_bb
);
3289 /* Merge TEST block into THEN block. Normally the THEN block won't have a
3290 label, but it might if there were || tests. That label's count should be
3291 zero, and it normally should be removed. */
3295 /* If THEN_BB has no successors, then there's a BARRIER after it.
3296 If COMBO_BB has more than one successor (THEN_BB), then that BARRIER
3297 is no longer needed, and in fact it is incorrect to leave it in
3299 if (EDGE_COUNT (then_bb
->succs
) == 0
3300 && EDGE_COUNT (combo_bb
->succs
) > 1)
3302 rtx_insn
*end
= NEXT_INSN (BB_END (then_bb
));
3303 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3304 end
= NEXT_INSN (end
);
3306 if (end
&& BARRIER_P (end
))
3309 merge_blocks (combo_bb
, then_bb
);
3313 /* The ELSE block, if it existed, had a label. That label count
3314 will almost always be zero, but odd things can happen when labels
3315 get their addresses taken. */
3318 /* If ELSE_BB has no successors, then there's a BARRIER after it.
3319 If COMBO_BB has more than one successor (ELSE_BB), then that BARRIER
3320 is no longer needed, and in fact it is incorrect to leave it in
3322 if (EDGE_COUNT (else_bb
->succs
) == 0
3323 && EDGE_COUNT (combo_bb
->succs
) > 1)
3325 rtx_insn
*end
= NEXT_INSN (BB_END (else_bb
));
3326 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3327 end
= NEXT_INSN (end
);
3329 if (end
&& BARRIER_P (end
))
3332 merge_blocks (combo_bb
, else_bb
);
3336 /* If there was no join block reported, that means it was not adjacent
3337 to the others, and so we cannot merge them. */
3341 rtx_insn
*last
= BB_END (combo_bb
);
3343 /* The outgoing edge for the current COMBO block should already
3344 be correct. Verify this. */
3345 if (EDGE_COUNT (combo_bb
->succs
) == 0)
3346 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
3347 || (NONJUMP_INSN_P (last
)
3348 && GET_CODE (PATTERN (last
)) == TRAP_IF
3349 && (TRAP_CONDITION (PATTERN (last
))
3350 == const_true_rtx
)));
3353 /* There should still be something at the end of the THEN or ELSE
3354 blocks taking us to our final destination. */
3355 gcc_assert (JUMP_P (last
)
3356 || (EDGE_SUCC (combo_bb
, 0)->dest
3357 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3359 && SIBLING_CALL_P (last
))
3360 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
3361 && can_throw_internal (last
)));
3364 /* The JOIN block may have had quite a number of other predecessors too.
3365 Since we've already merged the TEST, THEN and ELSE blocks, we should
3366 have only one remaining edge from our if-then-else diamond. If there
3367 is more than one remaining edge, it must come from elsewhere. There
3368 may be zero incoming edges if the THEN block didn't actually join
3369 back up (as with a call to a non-return function). */
3370 else if (EDGE_COUNT (join_bb
->preds
) < 2
3371 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3373 /* We can merge the JOIN cleanly and update the dataflow try
3374 again on this pass.*/
3375 merge_blocks (combo_bb
, join_bb
);
3380 /* We cannot merge the JOIN. */
3382 /* The outgoing edge for the current COMBO block should already
3383 be correct. Verify this. */
3384 gcc_assert (single_succ_p (combo_bb
)
3385 && single_succ (combo_bb
) == join_bb
);
3387 /* Remove the jump and cruft from the end of the COMBO block. */
3388 if (join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3389 tidy_fallthru_edge (single_succ_edge (combo_bb
));
3392 num_updated_if_blocks
++;
3395 /* Find a block ending in a simple IF condition and try to transform it
3396 in some way. When converting a multi-block condition, put the new code
3397 in the first such block and delete the rest. Return a pointer to this
3398 first block if some transformation was done. Return NULL otherwise. */
3401 find_if_header (basic_block test_bb
, int pass
)
3403 ce_if_block ce_info
;
3407 /* The kind of block we're looking for has exactly two successors. */
3408 if (EDGE_COUNT (test_bb
->succs
) != 2)
3411 then_edge
= EDGE_SUCC (test_bb
, 0);
3412 else_edge
= EDGE_SUCC (test_bb
, 1);
3414 if (df_get_bb_dirty (then_edge
->dest
))
3416 if (df_get_bb_dirty (else_edge
->dest
))
3419 /* Neither edge should be abnormal. */
3420 if ((then_edge
->flags
& EDGE_COMPLEX
)
3421 || (else_edge
->flags
& EDGE_COMPLEX
))
3424 /* Nor exit the loop. */
3425 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
3426 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
3429 /* The THEN edge is canonically the one that falls through. */
3430 if (then_edge
->flags
& EDGE_FALLTHRU
)
3432 else if (else_edge
->flags
& EDGE_FALLTHRU
)
3435 else_edge
= then_edge
;
3439 /* Otherwise this must be a multiway branch of some sort. */
3442 memset (&ce_info
, 0, sizeof (ce_info
));
3443 ce_info
.test_bb
= test_bb
;
3444 ce_info
.then_bb
= then_edge
->dest
;
3445 ce_info
.else_bb
= else_edge
->dest
;
3446 ce_info
.pass
= pass
;
3448 #ifdef IFCVT_MACHDEP_INIT
3449 IFCVT_MACHDEP_INIT (&ce_info
);
3452 if (!reload_completed
3453 && noce_find_if_block (test_bb
, then_edge
, else_edge
, pass
))
3456 if (reload_completed
3457 && targetm
.have_conditional_execution ()
3458 && cond_exec_find_if_block (&ce_info
))
3462 && optab_handler (ctrap_optab
, word_mode
) != CODE_FOR_nothing
3463 && find_cond_trap (test_bb
, then_edge
, else_edge
))
3466 if (dom_info_state (CDI_POST_DOMINATORS
) >= DOM_NO_FAST_QUERY
3467 && (reload_completed
|| !targetm
.have_conditional_execution ()))
3469 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
3471 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
3479 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
3480 /* Set this so we continue looking. */
3481 cond_exec_changed_p
= TRUE
;
3482 return ce_info
.test_bb
;
3485 /* Return true if a block has two edges, one of which falls through to the next
3486 block, and the other jumps to a specific block, so that we can tell if the
3487 block is part of an && test or an || test. Returns either -1 or the number
3488 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
3491 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
3494 int fallthru_p
= FALSE
;
3501 if (!cur_bb
|| !target_bb
)
3504 /* If no edges, obviously it doesn't jump or fallthru. */
3505 if (EDGE_COUNT (cur_bb
->succs
) == 0)
3508 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
3510 if (cur_edge
->flags
& EDGE_COMPLEX
)
3511 /* Anything complex isn't what we want. */
3514 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
3517 else if (cur_edge
->dest
== target_bb
)
3524 if ((jump_p
& fallthru_p
) == 0)
3527 /* Don't allow calls in the block, since this is used to group && and ||
3528 together for conditional execution support. ??? we should support
3529 conditional execution support across calls for IA-64 some day, but
3530 for now it makes the code simpler. */
3531 end
= BB_END (cur_bb
);
3532 insn
= BB_HEAD (cur_bb
);
3534 while (insn
!= NULL_RTX
)
3541 && !DEBUG_INSN_P (insn
)
3542 && GET_CODE (PATTERN (insn
)) != USE
3543 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
3549 insn
= NEXT_INSN (insn
);
3555 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3556 block. If so, we'll try to convert the insns to not require the branch.
3557 Return TRUE if we were successful at converting the block. */
3560 cond_exec_find_if_block (struct ce_if_block
* ce_info
)
3562 basic_block test_bb
= ce_info
->test_bb
;
3563 basic_block then_bb
= ce_info
->then_bb
;
3564 basic_block else_bb
= ce_info
->else_bb
;
3565 basic_block join_bb
= NULL_BLOCK
;
3570 ce_info
->last_test_bb
= test_bb
;
3572 /* We only ever should get here after reload,
3573 and if we have conditional execution. */
3574 gcc_assert (reload_completed
&& targetm
.have_conditional_execution ());
3576 /* Discover if any fall through predecessors of the current test basic block
3577 were && tests (which jump to the else block) or || tests (which jump to
3579 if (single_pred_p (test_bb
)
3580 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
3582 basic_block bb
= single_pred (test_bb
);
3583 basic_block target_bb
;
3584 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
3587 /* Determine if the preceding block is an && or || block. */
3588 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
3590 ce_info
->and_and_p
= TRUE
;
3591 target_bb
= else_bb
;
3593 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
3595 ce_info
->and_and_p
= FALSE
;
3596 target_bb
= then_bb
;
3599 target_bb
= NULL_BLOCK
;
3601 if (target_bb
&& n_insns
<= max_insns
)
3603 int total_insns
= 0;
3606 ce_info
->last_test_bb
= test_bb
;
3608 /* Found at least one && or || block, look for more. */
3611 ce_info
->test_bb
= test_bb
= bb
;
3612 total_insns
+= n_insns
;
3615 if (!single_pred_p (bb
))
3618 bb
= single_pred (bb
);
3619 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
3621 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
3623 ce_info
->num_multiple_test_blocks
= blocks
;
3624 ce_info
->num_multiple_test_insns
= total_insns
;
3626 if (ce_info
->and_and_p
)
3627 ce_info
->num_and_and_blocks
= blocks
;
3629 ce_info
->num_or_or_blocks
= blocks
;
3633 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3634 other than any || blocks which jump to the THEN block. */
3635 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
3638 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3639 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
3641 if (cur_edge
->flags
& EDGE_COMPLEX
)
3645 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
3647 if (cur_edge
->flags
& EDGE_COMPLEX
)
3651 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3652 if (EDGE_COUNT (then_bb
->succs
) > 0
3653 && (!single_succ_p (then_bb
)
3654 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3655 || (epilogue_completed
3656 && tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
3659 /* If the THEN block has no successors, conditional execution can still
3660 make a conditional call. Don't do this unless the ELSE block has
3661 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3662 Check for the last insn of the THEN block being an indirect jump, which
3663 is listed as not having any successors, but confuses the rest of the CE
3664 code processing. ??? we should fix this in the future. */
3665 if (EDGE_COUNT (then_bb
->succs
) == 0)
3667 if (single_pred_p (else_bb
) && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3669 rtx_insn
*last_insn
= BB_END (then_bb
);
3672 && NOTE_P (last_insn
)
3673 && last_insn
!= BB_HEAD (then_bb
))
3674 last_insn
= PREV_INSN (last_insn
);
3677 && JUMP_P (last_insn
)
3678 && ! simplejump_p (last_insn
))
3682 else_bb
= NULL_BLOCK
;
3688 /* If the THEN block's successor is the other edge out of the TEST block,
3689 then we have an IF-THEN combo without an ELSE. */
3690 else if (single_succ (then_bb
) == else_bb
)
3693 else_bb
= NULL_BLOCK
;
3696 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3697 has exactly one predecessor and one successor, and the outgoing edge
3698 is not complex, then we have an IF-THEN-ELSE combo. */
3699 else if (single_succ_p (else_bb
)
3700 && single_succ (then_bb
) == single_succ (else_bb
)
3701 && single_pred_p (else_bb
)
3702 && !(single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3703 && !(epilogue_completed
3704 && tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
3705 join_bb
= single_succ (else_bb
);
3707 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3711 num_possible_if_blocks
++;
3716 "\nIF-THEN%s block found, pass %d, start block %d "
3717 "[insn %d], then %d [%d]",
3718 (else_bb
) ? "-ELSE" : "",
3721 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
3723 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
3726 fprintf (dump_file
, ", else %d [%d]",
3728 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
3730 fprintf (dump_file
, ", join %d [%d]",
3732 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
3734 if (ce_info
->num_multiple_test_blocks
> 0)
3735 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
3736 ce_info
->num_multiple_test_blocks
,
3737 (ce_info
->and_and_p
) ? "&&" : "||",
3738 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
3739 ce_info
->last_test_bb
->index
,
3740 ((BB_HEAD (ce_info
->last_test_bb
))
3741 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
3744 fputc ('\n', dump_file
);
3747 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3748 first condition for free, since we've already asserted that there's a
3749 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3750 we checked the FALLTHRU flag, those are already adjacent to the last IF
3752 /* ??? As an enhancement, move the ELSE block. Have to deal with
3753 BLOCK notes, if by no other means than backing out the merge if they
3754 exist. Sticky enough I don't want to think about it now. */
3756 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
3758 if ((next
= next
->next_bb
) != join_bb
3759 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3767 /* Do the real work. */
3769 ce_info
->else_bb
= else_bb
;
3770 ce_info
->join_bb
= join_bb
;
3772 /* If we have && and || tests, try to first handle combining the && and ||
3773 tests into the conditional code, and if that fails, go back and handle
3774 it without the && and ||, which at present handles the && case if there
3775 was no ELSE block. */
3776 if (cond_exec_process_if_block (ce_info
, TRUE
))
3779 if (ce_info
->num_multiple_test_blocks
)
3783 if (cond_exec_process_if_block (ce_info
, FALSE
))
3790 /* Convert a branch over a trap, or a branch
3791 to a trap, into a conditional trap. */
3794 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
3796 basic_block then_bb
= then_edge
->dest
;
3797 basic_block else_bb
= else_edge
->dest
;
3798 basic_block other_bb
, trap_bb
;
3799 rtx_insn
*trap
, *jump
;
3801 rtx_insn
*cond_earliest
;
3804 /* Locate the block with the trap instruction. */
3805 /* ??? While we look for no successors, we really ought to allow
3806 EH successors. Need to fix merge_if_block for that to work. */
3807 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
3808 trap_bb
= then_bb
, other_bb
= else_bb
;
3809 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
3810 trap_bb
= else_bb
, other_bb
= then_bb
;
3816 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
3817 test_bb
->index
, trap_bb
->index
);
3820 /* If this is not a standard conditional jump, we can't parse it. */
3821 jump
= BB_END (test_bb
);
3822 cond
= noce_get_condition (jump
, &cond_earliest
, false);
3826 /* If the conditional jump is more than just a conditional jump, then
3827 we can not do if-conversion on this block. Give up for returnjump_p,
3828 changing a conditional return followed by unconditional trap for
3829 conditional trap followed by unconditional return is likely not
3830 beneficial and harder to handle. */
3831 if (! onlyjump_p (jump
) || returnjump_p (jump
))
3834 /* We must be comparing objects whose modes imply the size. */
3835 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3838 /* Reverse the comparison code, if necessary. */
3839 code
= GET_CODE (cond
);
3840 if (then_bb
== trap_bb
)
3842 code
= reversed_comparison_code (cond
, jump
);
3843 if (code
== UNKNOWN
)
3847 /* Attempt to generate the conditional trap. */
3848 seq
= gen_cond_trap (code
, copy_rtx (XEXP (cond
, 0)),
3849 copy_rtx (XEXP (cond
, 1)),
3850 TRAP_CODE (PATTERN (trap
)));
3854 /* Emit the new insns before cond_earliest. */
3855 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATION (trap
));
3857 /* Delete the trap block if possible. */
3858 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
3859 df_set_bb_dirty (test_bb
);
3860 df_set_bb_dirty (then_bb
);
3861 df_set_bb_dirty (else_bb
);
3863 if (EDGE_COUNT (trap_bb
->preds
) == 0)
3865 delete_basic_block (trap_bb
);
3869 /* Wire together the blocks again. */
3870 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
3871 single_succ_edge (test_bb
)->flags
|= EDGE_FALLTHRU
;
3872 else if (trap_bb
== then_bb
)
3877 lab
= JUMP_LABEL (jump
);
3878 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
3879 LABEL_NUSES (lab
) += 1;
3880 JUMP_LABEL (newjump
) = lab
;
3881 emit_barrier_after (newjump
);
3885 if (can_merge_blocks_p (test_bb
, other_bb
))
3887 merge_blocks (test_bb
, other_bb
);
3891 num_updated_if_blocks
++;
3895 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3899 block_has_only_trap (basic_block bb
)
3903 /* We're not the exit block. */
3904 if (bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3907 /* The block must have no successors. */
3908 if (EDGE_COUNT (bb
->succs
) > 0)
3911 /* The only instruction in the THEN block must be the trap. */
3912 trap
= first_active_insn (bb
);
3913 if (! (trap
== BB_END (bb
)
3914 && GET_CODE (PATTERN (trap
)) == TRAP_IF
3915 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
3921 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3922 transformable, but not necessarily the other. There need be no
3925 Return TRUE if we were successful at converting the block.
3927 Cases we'd like to look at:
3930 if (test) goto over; // x not live
3938 if (! test) goto label;
3941 if (test) goto E; // x not live
3955 (3) // This one's really only interesting for targets that can do
3956 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3957 // it results in multiple branches on a cache line, which often
3958 // does not sit well with predictors.
3960 if (test1) goto E; // predicted not taken
3976 (A) Don't do (2) if the branch is predicted against the block we're
3977 eliminating. Do it anyway if we can eliminate a branch; this requires
3978 that the sole successor of the eliminated block postdominate the other
3981 (B) With CE, on (3) we can steal from both sides of the if, creating
3990 Again, this is most useful if J postdominates.
3992 (C) CE substitutes for helpful life information.
3994 (D) These heuristics need a lot of work. */
3996 /* Tests for case 1 above. */
3999 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
4001 basic_block then_bb
= then_edge
->dest
;
4002 basic_block else_bb
= else_edge
->dest
;
4004 int then_bb_index
, then_prob
;
4005 rtx else_target
= NULL_RTX
;
4007 /* If we are partitioning hot/cold basic blocks, we don't want to
4008 mess up unconditional or indirect jumps that cross between hot
4011 Basic block partitioning may result in some jumps that appear to
4012 be optimizable (or blocks that appear to be mergeable), but which really
4013 must be left untouched (they are required to make it safely across
4014 partition boundaries). See the comments at the top of
4015 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4017 if ((BB_END (then_bb
)
4018 && JUMP_P (BB_END (then_bb
))
4019 && CROSSING_JUMP_P (BB_END (then_bb
)))
4020 || (BB_END (test_bb
)
4021 && JUMP_P (BB_END (test_bb
))
4022 && CROSSING_JUMP_P (BB_END (test_bb
)))
4023 || (BB_END (else_bb
)
4024 && JUMP_P (BB_END (else_bb
))
4025 && CROSSING_JUMP_P (BB_END (else_bb
))))
4028 /* THEN has one successor. */
4029 if (!single_succ_p (then_bb
))
4032 /* THEN does not fall through, but is not strange either. */
4033 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
4036 /* THEN has one predecessor. */
4037 if (!single_pred_p (then_bb
))
4040 /* THEN must do something. */
4041 if (forwarder_block_p (then_bb
))
4044 num_possible_if_blocks
++;
4047 "\nIF-CASE-1 found, start %d, then %d\n",
4048 test_bb
->index
, then_bb
->index
);
4050 if (then_edge
->probability
)
4051 then_prob
= REG_BR_PROB_BASE
- then_edge
->probability
;
4053 then_prob
= REG_BR_PROB_BASE
/ 2;
4055 /* We're speculating from the THEN path, we want to make sure the cost
4056 of speculation is within reason. */
4057 if (! cheap_bb_rtx_cost_p (then_bb
, then_prob
,
4058 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge
->src
),
4059 predictable_edge_p (then_edge
)))))
4062 if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4064 rtx_insn
*jump
= BB_END (else_edge
->src
);
4065 gcc_assert (JUMP_P (jump
));
4066 else_target
= JUMP_LABEL (jump
);
4069 /* Registers set are dead, or are predicable. */
4070 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
4071 single_succ_edge (then_bb
), 1))
4074 /* Conversion went ok, including moving the insns and fixing up the
4075 jump. Adjust the CFG to match. */
4077 /* We can avoid creating a new basic block if then_bb is immediately
4078 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
4079 through to else_bb. */
4081 if (then_bb
->next_bb
== else_bb
4082 && then_bb
->prev_bb
== test_bb
4083 && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
4085 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
4088 else if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4089 new_bb
= force_nonfallthru_and_redirect (FALLTHRU_EDGE (test_bb
),
4090 else_bb
, else_target
);
4092 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
4095 df_set_bb_dirty (test_bb
);
4096 df_set_bb_dirty (else_bb
);
4098 then_bb_index
= then_bb
->index
;
4099 delete_basic_block (then_bb
);
4101 /* Make rest of code believe that the newly created block is the THEN_BB
4102 block we removed. */
4105 df_bb_replace (then_bb_index
, new_bb
);
4106 /* This should have been done above via force_nonfallthru_and_redirect
4107 (possibly called from redirect_edge_and_branch_force). */
4108 gcc_checking_assert (BB_PARTITION (new_bb
) == BB_PARTITION (test_bb
));
4112 num_updated_if_blocks
++;
4117 /* Test for case 2 above. */
4120 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
4122 basic_block then_bb
= then_edge
->dest
;
4123 basic_block else_bb
= else_edge
->dest
;
4125 int then_prob
, else_prob
;
4127 /* We do not want to speculate (empty) loop latches. */
4129 && else_bb
->loop_father
->latch
== else_bb
)
4132 /* If we are partitioning hot/cold basic blocks, we don't want to
4133 mess up unconditional or indirect jumps that cross between hot
4136 Basic block partitioning may result in some jumps that appear to
4137 be optimizable (or blocks that appear to be mergeable), but which really
4138 must be left untouched (they are required to make it safely across
4139 partition boundaries). See the comments at the top of
4140 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4142 if ((BB_END (then_bb
)
4143 && JUMP_P (BB_END (then_bb
))
4144 && CROSSING_JUMP_P (BB_END (then_bb
)))
4145 || (BB_END (test_bb
)
4146 && JUMP_P (BB_END (test_bb
))
4147 && CROSSING_JUMP_P (BB_END (test_bb
)))
4148 || (BB_END (else_bb
)
4149 && JUMP_P (BB_END (else_bb
))
4150 && CROSSING_JUMP_P (BB_END (else_bb
))))
4153 /* ELSE has one successor. */
4154 if (!single_succ_p (else_bb
))
4157 else_succ
= single_succ_edge (else_bb
);
4159 /* ELSE outgoing edge is not complex. */
4160 if (else_succ
->flags
& EDGE_COMPLEX
)
4163 /* ELSE has one predecessor. */
4164 if (!single_pred_p (else_bb
))
4167 /* THEN is not EXIT. */
4168 if (then_bb
->index
< NUM_FIXED_BLOCKS
)
4171 if (else_edge
->probability
)
4173 else_prob
= else_edge
->probability
;
4174 then_prob
= REG_BR_PROB_BASE
- else_prob
;
4178 else_prob
= REG_BR_PROB_BASE
/ 2;
4179 then_prob
= REG_BR_PROB_BASE
/ 2;
4182 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
4183 if (else_prob
> then_prob
)
4185 else if (else_succ
->dest
->index
< NUM_FIXED_BLOCKS
4186 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
4192 num_possible_if_blocks
++;
4195 "\nIF-CASE-2 found, start %d, else %d\n",
4196 test_bb
->index
, else_bb
->index
);
4198 /* We're speculating from the ELSE path, we want to make sure the cost
4199 of speculation is within reason. */
4200 if (! cheap_bb_rtx_cost_p (else_bb
, else_prob
,
4201 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge
->src
),
4202 predictable_edge_p (else_edge
)))))
4205 /* Registers set are dead, or are predicable. */
4206 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
, 0))
4209 /* Conversion went ok, including moving the insns and fixing up the
4210 jump. Adjust the CFG to match. */
4212 df_set_bb_dirty (test_bb
);
4213 df_set_bb_dirty (then_bb
);
4214 delete_basic_block (else_bb
);
4217 num_updated_if_blocks
++;
4219 /* ??? We may now fallthru from one of THEN's successors into a join
4220 block. Rerun cleanup_cfg? Examine things manually? Wait? */
4225 /* Used by the code above to perform the actual rtl transformations.
4226 Return TRUE if successful.
4228 TEST_BB is the block containing the conditional branch. MERGE_BB
4229 is the block containing the code to manipulate. DEST_EDGE is an
4230 edge representing a jump to the join block; after the conversion,
4231 TEST_BB should be branching to its destination.
4232 REVERSEP is true if the sense of the branch should be reversed. */
4235 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
4236 basic_block other_bb
, edge dest_edge
, int reversep
)
4238 basic_block new_dest
= dest_edge
->dest
;
4239 rtx_insn
*head
, *end
, *jump
;
4240 rtx_insn
*earliest
= NULL
;
4242 bitmap merge_set
= NULL
;
4243 /* Number of pending changes. */
4244 int n_validated_changes
= 0;
4245 rtx new_dest_label
= NULL_RTX
;
4247 jump
= BB_END (test_bb
);
4249 /* Find the extent of the real code in the merge block. */
4250 head
= BB_HEAD (merge_bb
);
4251 end
= BB_END (merge_bb
);
4253 while (DEBUG_INSN_P (end
) && end
!= head
)
4254 end
= PREV_INSN (end
);
4256 /* If merge_bb ends with a tablejump, predicating/moving insn's
4257 into test_bb and then deleting merge_bb will result in the jumptable
4258 that follows merge_bb being removed along with merge_bb and then we
4259 get an unresolved reference to the jumptable. */
4260 if (tablejump_p (end
, NULL
, NULL
))
4264 head
= NEXT_INSN (head
);
4265 while (DEBUG_INSN_P (head
) && head
!= end
)
4266 head
= NEXT_INSN (head
);
4274 head
= NEXT_INSN (head
);
4275 while (DEBUG_INSN_P (head
) && head
!= end
)
4276 head
= NEXT_INSN (head
);
4281 if (!onlyjump_p (end
))
4288 end
= PREV_INSN (end
);
4289 while (DEBUG_INSN_P (end
) && end
!= head
)
4290 end
= PREV_INSN (end
);
4293 /* Don't move frame-related insn across the conditional branch. This
4294 can lead to one of the paths of the branch having wrong unwind info. */
4295 if (epilogue_completed
)
4297 rtx_insn
*insn
= head
;
4300 if (INSN_P (insn
) && RTX_FRAME_RELATED_P (insn
))
4304 insn
= NEXT_INSN (insn
);
4308 /* Disable handling dead code by conditional execution if the machine needs
4309 to do anything funny with the tests, etc. */
4310 #ifndef IFCVT_MODIFY_TESTS
4311 if (targetm
.have_conditional_execution ())
4313 /* In the conditional execution case, we have things easy. We know
4314 the condition is reversible. We don't have to check life info
4315 because we're going to conditionally execute the code anyway.
4316 All that's left is making sure the insns involved can actually
4321 cond
= cond_exec_get_condition (jump
);
4325 rtx note
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
4326 int prob_val
= (note
? XINT (note
, 0) : -1);
4330 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
4333 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
4336 prob_val
= REG_BR_PROB_BASE
- prob_val
;
4339 if (cond_exec_process_insns (NULL
, head
, end
, cond
, prob_val
, 0)
4340 && verify_changes (0))
4341 n_validated_changes
= num_validated_changes ();
4349 /* If we allocated new pseudos (e.g. in the conditional move
4350 expander called from noce_emit_cmove), we must resize the
4352 if (max_regno
< max_reg_num ())
4353 max_regno
= max_reg_num ();
4355 /* Try the NCE path if the CE path did not result in any changes. */
4356 if (n_validated_changes
== 0)
4363 /* In the non-conditional execution case, we have to verify that there
4364 are no trapping operations, no calls, no references to memory, and
4365 that any registers modified are dead at the branch site. */
4367 if (!any_condjump_p (jump
))
4370 /* Find the extent of the conditional. */
4371 cond
= noce_get_condition (jump
, &earliest
, false);
4375 live
= BITMAP_ALLOC (®_obstack
);
4376 simulate_backwards_to_point (merge_bb
, live
, end
);
4377 success
= can_move_insns_across (head
, end
, earliest
, jump
,
4379 df_get_live_in (other_bb
), NULL
);
4384 /* Collect the set of registers set in MERGE_BB. */
4385 merge_set
= BITMAP_ALLOC (®_obstack
);
4387 FOR_BB_INSNS (merge_bb
, insn
)
4388 if (NONDEBUG_INSN_P (insn
))
4389 df_simulate_find_defs (insn
, merge_set
);
4391 /* If shrink-wrapping, disable this optimization when test_bb is
4392 the first basic block and merge_bb exits. The idea is to not
4393 move code setting up a return register as that may clobber a
4394 register used to pass function parameters, which then must be
4395 saved in caller-saved regs. A caller-saved reg requires the
4396 prologue, killing a shrink-wrap opportunity. */
4397 if ((SHRINK_WRAPPING_ENABLED
&& !epilogue_completed
)
4398 && ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
== test_bb
4399 && single_succ_p (new_dest
)
4400 && single_succ (new_dest
) == EXIT_BLOCK_PTR_FOR_FN (cfun
)
4401 && bitmap_intersect_p (df_get_live_in (new_dest
), merge_set
))
4406 return_regs
= BITMAP_ALLOC (®_obstack
);
4408 /* Start off with the intersection of regs used to pass
4409 params and regs used to return values. */
4410 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
4411 if (FUNCTION_ARG_REGNO_P (i
)
4412 && targetm
.calls
.function_value_regno_p (i
))
4413 bitmap_set_bit (return_regs
, INCOMING_REGNO (i
));
4415 bitmap_and_into (return_regs
,
4416 df_get_live_out (ENTRY_BLOCK_PTR_FOR_FN (cfun
)));
4417 bitmap_and_into (return_regs
,
4418 df_get_live_in (EXIT_BLOCK_PTR_FOR_FN (cfun
)));
4419 if (!bitmap_empty_p (return_regs
))
4421 FOR_BB_INSNS_REVERSE (new_dest
, insn
)
4422 if (NONDEBUG_INSN_P (insn
))
4426 /* If this insn sets any reg in return_regs, add all
4427 reg uses to the set of regs we're interested in. */
4428 FOR_EACH_INSN_DEF (def
, insn
)
4429 if (bitmap_bit_p (return_regs
, DF_REF_REGNO (def
)))
4431 df_simulate_uses (insn
, return_regs
);
4435 if (bitmap_intersect_p (merge_set
, return_regs
))
4437 BITMAP_FREE (return_regs
);
4438 BITMAP_FREE (merge_set
);
4442 BITMAP_FREE (return_regs
);
4447 /* We don't want to use normal invert_jump or redirect_jump because
4448 we don't want to delete_insn called. Also, we want to do our own
4449 change group management. */
4451 old_dest
= JUMP_LABEL (jump
);
4452 if (other_bb
!= new_dest
)
4454 if (!any_condjump_p (jump
))
4457 if (JUMP_P (BB_END (dest_edge
->src
)))
4458 new_dest_label
= JUMP_LABEL (BB_END (dest_edge
->src
));
4459 else if (new_dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4460 new_dest_label
= ret_rtx
;
4462 new_dest_label
= block_label (new_dest
);
4465 ? ! invert_jump_1 (jump
, new_dest_label
)
4466 : ! redirect_jump_1 (jump
, new_dest_label
))
4470 if (verify_changes (n_validated_changes
))
4471 confirm_change_group ();
4475 if (other_bb
!= new_dest
)
4477 redirect_jump_2 (jump
, old_dest
, new_dest_label
, 0, reversep
);
4479 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
4482 gcov_type count
, probability
;
4483 count
= BRANCH_EDGE (test_bb
)->count
;
4484 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
4485 FALLTHRU_EDGE (test_bb
)->count
= count
;
4486 probability
= BRANCH_EDGE (test_bb
)->probability
;
4487 BRANCH_EDGE (test_bb
)->probability
4488 = FALLTHRU_EDGE (test_bb
)->probability
;
4489 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
4490 update_br_prob_note (test_bb
);
4494 /* Move the insns out of MERGE_BB to before the branch. */
4499 if (end
== BB_END (merge_bb
))
4500 BB_END (merge_bb
) = PREV_INSN (head
);
4502 /* PR 21767: when moving insns above a conditional branch, the REG_EQUAL
4503 notes being moved might become invalid. */
4509 if (! INSN_P (insn
))
4511 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
4514 remove_note (insn
, note
);
4515 } while (insn
!= end
&& (insn
= NEXT_INSN (insn
)));
4517 /* PR46315: when moving insns above a conditional branch, the REG_EQUAL
4518 notes referring to the registers being set might become invalid. */
4524 EXECUTE_IF_SET_IN_BITMAP (merge_set
, 0, i
, bi
)
4525 remove_reg_equal_equiv_notes_for_regno (i
);
4527 BITMAP_FREE (merge_set
);
4530 reorder_insns (head
, end
, PREV_INSN (earliest
));
4533 /* Remove the jump and edge if we can. */
4534 if (other_bb
== new_dest
)
4537 remove_edge (BRANCH_EDGE (test_bb
));
4538 /* ??? Can't merge blocks here, as then_bb is still in use.
4539 At minimum, the merge will get done just before bb-reorder. */
4548 BITMAP_FREE (merge_set
);
4553 /* Main entry point for all if-conversion. AFTER_COMBINE is true if
4554 we are after combine pass. */
4557 if_convert (bool after_combine
)
4564 df_live_add_problem ();
4565 df_live_set_all_dirty ();
4568 /* Record whether we are after combine pass. */
4569 ifcvt_after_combine
= after_combine
;
4570 num_possible_if_blocks
= 0;
4571 num_updated_if_blocks
= 0;
4572 num_true_changes
= 0;
4574 loop_optimizer_init (AVOID_CFG_MODIFICATIONS
);
4575 mark_loop_exit_edges ();
4576 loop_optimizer_finalize ();
4577 free_dominance_info (CDI_DOMINATORS
);
4579 /* Compute postdominators. */
4580 calculate_dominance_info (CDI_POST_DOMINATORS
);
4582 df_set_flags (DF_LR_RUN_DCE
);
4584 /* Go through each of the basic blocks looking for things to convert. If we
4585 have conditional execution, we make multiple passes to allow us to handle
4586 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
4591 /* Only need to do dce on the first pass. */
4592 df_clear_flags (DF_LR_RUN_DCE
);
4593 cond_exec_changed_p
= FALSE
;
4596 #ifdef IFCVT_MULTIPLE_DUMPS
4597 if (dump_file
&& pass
> 1)
4598 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
4601 FOR_EACH_BB_FN (bb
, cfun
)
4604 while (!df_get_bb_dirty (bb
)
4605 && (new_bb
= find_if_header (bb
, pass
)) != NULL
)
4609 #ifdef IFCVT_MULTIPLE_DUMPS
4610 if (dump_file
&& cond_exec_changed_p
)
4611 print_rtl_with_bb (dump_file
, get_insns (), dump_flags
);
4614 while (cond_exec_changed_p
);
4616 #ifdef IFCVT_MULTIPLE_DUMPS
4618 fprintf (dump_file
, "\n\n========== no more changes\n");
4621 free_dominance_info (CDI_POST_DOMINATORS
);
4626 clear_aux_for_blocks ();
4628 /* If we allocated new pseudos, we must resize the array for sched1. */
4629 if (max_regno
< max_reg_num ())
4630 max_regno
= max_reg_num ();
4632 /* Write the final stats. */
4633 if (dump_file
&& num_possible_if_blocks
> 0)
4636 "\n%d possible IF blocks searched.\n",
4637 num_possible_if_blocks
);
4639 "%d IF blocks converted.\n",
4640 num_updated_if_blocks
);
4642 "%d true changes made.\n\n\n",
4647 df_remove_problem (df_live
);
4649 #ifdef ENABLE_CHECKING
4650 verify_flow_info ();
4654 /* If-conversion and CFG cleanup. */
4656 rest_of_handle_if_conversion (void)
4658 if (flag_if_conversion
)
4662 dump_reg_info (dump_file
);
4663 dump_flow_info (dump_file
, dump_flags
);
4665 cleanup_cfg (CLEANUP_EXPENSIVE
);
4675 const pass_data pass_data_rtl_ifcvt
=
4677 RTL_PASS
, /* type */
4679 OPTGROUP_NONE
, /* optinfo_flags */
4680 TV_IFCVT
, /* tv_id */
4681 0, /* properties_required */
4682 0, /* properties_provided */
4683 0, /* properties_destroyed */
4684 0, /* todo_flags_start */
4685 TODO_df_finish
, /* todo_flags_finish */
4688 class pass_rtl_ifcvt
: public rtl_opt_pass
4691 pass_rtl_ifcvt (gcc::context
*ctxt
)
4692 : rtl_opt_pass (pass_data_rtl_ifcvt
, ctxt
)
4695 /* opt_pass methods: */
4696 virtual bool gate (function
*)
4698 return (optimize
> 0) && dbg_cnt (if_conversion
);
4701 virtual unsigned int execute (function
*)
4703 return rest_of_handle_if_conversion ();
4706 }; // class pass_rtl_ifcvt
4711 make_pass_rtl_ifcvt (gcc::context
*ctxt
)
4713 return new pass_rtl_ifcvt (ctxt
);
4717 /* Rerun if-conversion, as combine may have simplified things enough
4718 to now meet sequence length restrictions. */
4722 const pass_data pass_data_if_after_combine
=
4724 RTL_PASS
, /* type */
4726 OPTGROUP_NONE
, /* optinfo_flags */
4727 TV_IFCVT
, /* tv_id */
4728 0, /* properties_required */
4729 0, /* properties_provided */
4730 0, /* properties_destroyed */
4731 0, /* todo_flags_start */
4732 TODO_df_finish
, /* todo_flags_finish */
4735 class pass_if_after_combine
: public rtl_opt_pass
4738 pass_if_after_combine (gcc::context
*ctxt
)
4739 : rtl_opt_pass (pass_data_if_after_combine
, ctxt
)
4742 /* opt_pass methods: */
4743 virtual bool gate (function
*)
4745 return optimize
> 0 && flag_if_conversion
4746 && dbg_cnt (if_after_combine
);
4749 virtual unsigned int execute (function
*)
4755 }; // class pass_if_after_combine
4760 make_pass_if_after_combine (gcc::context
*ctxt
)
4762 return new pass_if_after_combine (ctxt
);
4768 const pass_data pass_data_if_after_reload
=
4770 RTL_PASS
, /* type */
4772 OPTGROUP_NONE
, /* optinfo_flags */
4773 TV_IFCVT2
, /* tv_id */
4774 0, /* properties_required */
4775 0, /* properties_provided */
4776 0, /* properties_destroyed */
4777 0, /* todo_flags_start */
4778 TODO_df_finish
, /* todo_flags_finish */
4781 class pass_if_after_reload
: public rtl_opt_pass
4784 pass_if_after_reload (gcc::context
*ctxt
)
4785 : rtl_opt_pass (pass_data_if_after_reload
, ctxt
)
4788 /* opt_pass methods: */
4789 virtual bool gate (function
*)
4791 return optimize
> 0 && flag_if_conversion2
4792 && dbg_cnt (if_after_reload
);
4795 virtual unsigned int execute (function
*)
4801 }; // class pass_if_after_reload
4806 make_pass_if_after_reload (gcc::context
*ctxt
)
4808 return new pass_if_after_reload (ctxt
);