1 /* If-conversion support.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
30 #include "insn-config.h"
33 #include "hard-reg-set.h"
34 #include "basic-block.h"
38 #include "diagnostic-core.h"
44 #include "tree-pass.h"
50 #ifndef HAVE_conditional_move
51 #define HAVE_conditional_move 0
63 #ifndef MAX_CONDITIONAL_EXECUTE
64 #define MAX_CONDITIONAL_EXECUTE \
65 (BRANCH_COST (optimize_function_for_speed_p (cfun), false) \
69 #define IFCVT_MULTIPLE_DUMPS 1
71 #define NULL_BLOCK ((basic_block) NULL)
73 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
74 static int num_possible_if_blocks
;
76 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
78 static int num_updated_if_blocks
;
80 /* # of changes made. */
81 static int num_true_changes
;
83 /* Whether conditional execution changes were made. */
84 static int cond_exec_changed_p
;
86 /* Forward references. */
87 static int count_bb_insns (const_basic_block
);
88 static bool cheap_bb_rtx_cost_p (const_basic_block
, int);
89 static rtx
first_active_insn (basic_block
);
90 static rtx
last_active_insn (basic_block
, int);
91 static basic_block
block_fallthru (basic_block
);
92 static int cond_exec_process_insns (ce_if_block_t
*, rtx
, rtx
, rtx
, rtx
, int);
93 static rtx
cond_exec_get_condition (rtx
);
94 static rtx
noce_get_condition (rtx
, rtx
*, bool);
95 static int noce_operand_ok (const_rtx
);
96 static void merge_if_block (ce_if_block_t
*);
97 static int find_cond_trap (basic_block
, edge
, edge
);
98 static basic_block
find_if_header (basic_block
, int);
99 static int block_jumps_and_fallthru_p (basic_block
, basic_block
);
100 static int noce_find_if_block (basic_block
, edge
, edge
, int);
101 static int cond_exec_find_if_block (ce_if_block_t
*);
102 static int find_if_case_1 (basic_block
, edge
, edge
);
103 static int find_if_case_2 (basic_block
, edge
, edge
);
104 static int find_memory (rtx
*, void *);
105 static int dead_or_predicable (basic_block
, basic_block
, basic_block
,
107 static void noce_emit_move_insn (rtx
, rtx
);
108 static rtx
block_has_only_trap (basic_block
);
110 /* Count the number of non-jump active insns in BB. */
113 count_bb_insns (const_basic_block bb
)
116 rtx insn
= BB_HEAD (bb
);
120 if (CALL_P (insn
) || NONJUMP_INSN_P (insn
))
123 if (insn
== BB_END (bb
))
125 insn
= NEXT_INSN (insn
);
131 /* Determine whether the total insn_rtx_cost on non-jump insns in
132 basic block BB is less than MAX_COST. This function returns
133 false if the cost of any instruction could not be estimated. */
136 cheap_bb_rtx_cost_p (const_basic_block bb
, int max_cost
)
139 rtx insn
= BB_HEAD (bb
);
140 bool speed
= optimize_bb_for_speed_p (bb
);
144 if (NONJUMP_INSN_P (insn
))
146 int cost
= insn_rtx_cost (PATTERN (insn
), speed
);
150 /* If this instruction is the load or set of a "stack" register,
151 such as a floating point register on x87, then the cost of
152 speculatively executing this insn may need to include
153 the additional cost of popping its result off of the
154 register stack. Unfortunately, correctly recognizing and
155 accounting for this additional overhead is tricky, so for
156 now we simply prohibit such speculative execution. */
159 rtx set
= single_set (insn
);
160 if (set
&& STACK_REG_P (SET_DEST (set
)))
166 if (count
>= max_cost
)
169 else if (CALL_P (insn
))
172 if (insn
== BB_END (bb
))
174 insn
= NEXT_INSN (insn
);
180 /* Return the first non-jump active insn in the basic block. */
183 first_active_insn (basic_block bb
)
185 rtx insn
= BB_HEAD (bb
);
189 if (insn
== BB_END (bb
))
191 insn
= NEXT_INSN (insn
);
194 while (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
196 if (insn
== BB_END (bb
))
198 insn
= NEXT_INSN (insn
);
207 /* Return the last non-jump active (non-jump) insn in the basic block. */
210 last_active_insn (basic_block bb
, int skip_use_p
)
212 rtx insn
= BB_END (bb
);
213 rtx head
= BB_HEAD (bb
);
217 || DEBUG_INSN_P (insn
)
219 && NONJUMP_INSN_P (insn
)
220 && GET_CODE (PATTERN (insn
)) == USE
))
224 insn
= PREV_INSN (insn
);
233 /* Return the basic block reached by falling though the basic block BB. */
236 block_fallthru (basic_block bb
)
241 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
242 if (e
->flags
& EDGE_FALLTHRU
)
245 return (e
) ? e
->dest
: NULL_BLOCK
;
248 /* Go through a bunch of insns, converting them to conditional
249 execution format if possible. Return TRUE if all of the non-note
250 insns were processed. */
253 cond_exec_process_insns (ce_if_block_t
*ce_info ATTRIBUTE_UNUSED
,
254 /* if block information */rtx start
,
255 /* first insn to look at */rtx end
,
256 /* last insn to look at */rtx test
,
257 /* conditional execution test */rtx prob_val
,
258 /* probability of branch taken. */int mod_ok
)
260 int must_be_last
= FALSE
;
268 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
270 if (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
273 gcc_assert(NONJUMP_INSN_P (insn
) || CALL_P (insn
));
275 /* Remove USE insns that get in the way. */
276 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
278 /* ??? Ug. Actually unlinking the thing is problematic,
279 given what we'd have to coordinate with our callers. */
280 SET_INSN_DELETED (insn
);
284 /* Last insn wasn't last? */
288 if (modified_in_p (test
, insn
))
295 /* Now build the conditional form of the instruction. */
296 pattern
= PATTERN (insn
);
297 xtest
= copy_rtx (test
);
299 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
301 if (GET_CODE (pattern
) == COND_EXEC
)
303 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
306 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
307 COND_EXEC_TEST (pattern
));
308 pattern
= COND_EXEC_CODE (pattern
);
311 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
313 /* If the machine needs to modify the insn being conditionally executed,
314 say for example to force a constant integer operand into a temp
315 register, do so here. */
316 #ifdef IFCVT_MODIFY_INSN
317 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
322 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
324 if (CALL_P (insn
) && prob_val
)
325 validate_change (insn
, ®_NOTES (insn
),
326 alloc_EXPR_LIST (REG_BR_PROB
, prob_val
,
327 REG_NOTES (insn
)), 1);
337 /* Return the condition for a jump. Do not do any special processing. */
340 cond_exec_get_condition (rtx jump
)
344 if (any_condjump_p (jump
))
345 test_if
= SET_SRC (pc_set (jump
));
348 cond
= XEXP (test_if
, 0);
350 /* If this branches to JUMP_LABEL when the condition is false,
351 reverse the condition. */
352 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
353 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
355 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
359 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
366 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
367 to conditional execution. Return TRUE if we were successful at
368 converting the block. */
371 cond_exec_process_if_block (ce_if_block_t
* ce_info
,
372 /* if block information */int do_multiple_p
)
374 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
375 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
376 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
377 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
378 rtx then_start
; /* first insn in THEN block */
379 rtx then_end
; /* last insn + 1 in THEN block */
380 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
381 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
382 int max
; /* max # of insns to convert. */
383 int then_mod_ok
; /* whether conditional mods are ok in THEN */
384 rtx true_expr
; /* test for else block insns */
385 rtx false_expr
; /* test for then block insns */
386 rtx true_prob_val
; /* probability of else block */
387 rtx false_prob_val
; /* probability of then block */
388 rtx then_last_head
= NULL_RTX
; /* Last match at the head of THEN */
389 rtx else_last_head
= NULL_RTX
; /* Last match at the head of ELSE */
390 rtx then_first_tail
= NULL_RTX
; /* First match at the tail of THEN */
391 rtx else_first_tail
= NULL_RTX
; /* First match at the tail of ELSE */
392 int then_n_insns
, else_n_insns
, n_insns
;
393 enum rtx_code false_code
;
395 /* If test is comprised of && or || elements, and we've failed at handling
396 all of them together, just use the last test if it is the special case of
397 && elements without an ELSE block. */
398 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
400 if (else_bb
|| ! ce_info
->and_and_p
)
403 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
404 ce_info
->num_multiple_test_blocks
= 0;
405 ce_info
->num_and_and_blocks
= 0;
406 ce_info
->num_or_or_blocks
= 0;
409 /* Find the conditional jump to the ELSE or JOIN part, and isolate
411 test_expr
= cond_exec_get_condition (BB_END (test_bb
));
415 /* If the conditional jump is more than just a conditional jump,
416 then we can not do conditional execution conversion on this block. */
417 if (! onlyjump_p (BB_END (test_bb
)))
420 /* Collect the bounds of where we're to search, skipping any labels, jumps
421 and notes at the beginning and end of the block. Then count the total
422 number of insns and see if it is small enough to convert. */
423 then_start
= first_active_insn (then_bb
);
424 then_end
= last_active_insn (then_bb
, TRUE
);
425 then_n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
426 n_insns
= then_n_insns
;
427 max
= MAX_CONDITIONAL_EXECUTE
;
434 else_start
= first_active_insn (else_bb
);
435 else_end
= last_active_insn (else_bb
, TRUE
);
436 else_n_insns
= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
437 n_insns
+= else_n_insns
;
439 /* Look for matching sequences at the head and tail of the two blocks,
440 and limit the range of insns to be converted if possible. */
441 n_matching
= flow_find_cross_jump (then_bb
, else_bb
,
442 &then_first_tail
, &else_first_tail
);
443 if (then_first_tail
== BB_HEAD (then_bb
))
444 then_start
= then_end
= NULL_RTX
;
445 if (else_first_tail
== BB_HEAD (else_bb
))
446 else_start
= else_end
= NULL_RTX
;
451 then_end
= prev_active_insn (then_first_tail
);
453 else_end
= prev_active_insn (else_first_tail
);
454 n_insns
-= 2 * n_matching
;
457 if (then_start
&& else_start
)
459 int longest_match
= MIN (then_n_insns
- n_matching
,
460 else_n_insns
- n_matching
);
462 = flow_find_head_matching_sequence (then_bb
, else_bb
,
471 /* We won't pass the insns in the head sequence to
472 cond_exec_process_insns, so we need to test them here
473 to make sure that they don't clobber the condition. */
474 for (insn
= BB_HEAD (then_bb
);
475 insn
!= NEXT_INSN (then_last_head
);
476 insn
= NEXT_INSN (insn
))
477 if (!LABEL_P (insn
) && !NOTE_P (insn
)
478 && !DEBUG_INSN_P (insn
)
479 && modified_in_p (test_expr
, insn
))
483 if (then_last_head
== then_end
)
484 then_start
= then_end
= NULL_RTX
;
485 if (else_last_head
== else_end
)
486 else_start
= else_end
= NULL_RTX
;
491 then_start
= next_active_insn (then_last_head
);
493 else_start
= next_active_insn (else_last_head
);
494 n_insns
-= 2 * n_matching
;
502 /* Map test_expr/test_jump into the appropriate MD tests to use on
503 the conditionally executed code. */
505 true_expr
= test_expr
;
507 false_code
= reversed_comparison_code (true_expr
, BB_END (test_bb
));
508 if (false_code
!= UNKNOWN
)
509 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
510 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
512 false_expr
= NULL_RTX
;
514 #ifdef IFCVT_MODIFY_TESTS
515 /* If the machine description needs to modify the tests, such as setting a
516 conditional execution register from a comparison, it can do so here. */
517 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
519 /* See if the conversion failed. */
520 if (!true_expr
|| !false_expr
)
524 true_prob_val
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
527 true_prob_val
= XEXP (true_prob_val
, 0);
528 false_prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (true_prob_val
));
531 false_prob_val
= NULL_RTX
;
533 /* If we have && or || tests, do them here. These tests are in the adjacent
534 blocks after the first block containing the test. */
535 if (ce_info
->num_multiple_test_blocks
> 0)
537 basic_block bb
= test_bb
;
538 basic_block last_test_bb
= ce_info
->last_test_bb
;
547 enum rtx_code f_code
;
549 bb
= block_fallthru (bb
);
550 start
= first_active_insn (bb
);
551 end
= last_active_insn (bb
, TRUE
);
553 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
554 false_prob_val
, FALSE
))
557 /* If the conditional jump is more than just a conditional jump, then
558 we can not do conditional execution conversion on this block. */
559 if (! onlyjump_p (BB_END (bb
)))
562 /* Find the conditional jump and isolate the test. */
563 t
= cond_exec_get_condition (BB_END (bb
));
567 f_code
= reversed_comparison_code (t
, BB_END (bb
));
568 if (f_code
== UNKNOWN
)
571 f
= gen_rtx_fmt_ee (f_code
, GET_MODE (t
), XEXP (t
, 0), XEXP (t
, 1));
572 if (ce_info
->and_and_p
)
574 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
575 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
579 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
580 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
583 /* If the machine description needs to modify the tests, such as
584 setting a conditional execution register from a comparison, it can
586 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
587 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
589 /* See if the conversion failed. */
597 while (bb
!= last_test_bb
);
600 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
601 on then THEN block. */
602 then_mod_ok
= (else_bb
== NULL_BLOCK
);
604 /* Go through the THEN and ELSE blocks converting the insns if possible
605 to conditional execution. */
609 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
610 false_expr
, false_prob_val
,
614 if (else_bb
&& else_end
615 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
616 true_expr
, true_prob_val
, TRUE
))
619 /* If we cannot apply the changes, fail. Do not go through the normal fail
620 processing, since apply_change_group will call cancel_changes. */
621 if (! apply_change_group ())
623 #ifdef IFCVT_MODIFY_CANCEL
624 /* Cancel any machine dependent changes. */
625 IFCVT_MODIFY_CANCEL (ce_info
);
630 #ifdef IFCVT_MODIFY_FINAL
631 /* Do any machine dependent final modifications. */
632 IFCVT_MODIFY_FINAL (ce_info
);
635 /* Conversion succeeded. */
637 fprintf (dump_file
, "%d insn%s converted to conditional execution.\n",
638 n_insns
, (n_insns
== 1) ? " was" : "s were");
640 /* Merge the blocks! If we had matching sequences, make sure to delete one
641 copy at the appropriate location first: delete the copy in the THEN branch
642 for a tail sequence so that the remaining one is executed last for both
643 branches, and delete the copy in the ELSE branch for a head sequence so
644 that the remaining one is executed first for both branches. */
647 rtx from
= then_first_tail
;
649 from
= next_active_insn (from
);
650 delete_insn_chain (from
, BB_END (then_bb
), false);
653 delete_insn_chain (first_active_insn (else_bb
), else_last_head
, false);
655 merge_if_block (ce_info
);
656 cond_exec_changed_p
= TRUE
;
660 #ifdef IFCVT_MODIFY_CANCEL
661 /* Cancel any machine dependent changes. */
662 IFCVT_MODIFY_CANCEL (ce_info
);
669 /* Used by noce_process_if_block to communicate with its subroutines.
671 The subroutines know that A and B may be evaluated freely. They
672 know that X is a register. They should insert new instructions
673 before cond_earliest. */
677 /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block. */
678 basic_block test_bb
, then_bb
, else_bb
, join_bb
;
680 /* The jump that ends TEST_BB. */
683 /* The jump condition. */
686 /* New insns should be inserted before this one. */
689 /* Insns in the THEN and ELSE block. There is always just this
690 one insns in those blocks. The insns are single_set insns.
691 If there was no ELSE block, INSN_B is the last insn before
692 COND_EARLIEST, or NULL_RTX. In the former case, the insn
693 operands are still valid, as if INSN_B was moved down below
697 /* The SET_SRC of INSN_A and INSN_B. */
700 /* The SET_DEST of INSN_A. */
703 /* True if this if block is not canonical. In the canonical form of
704 if blocks, the THEN_BB is the block reached via the fallthru edge
705 from TEST_BB. For the noce transformations, we allow the symmetric
707 bool then_else_reversed
;
709 /* Estimated cost of the particular branch instruction. */
713 static rtx
noce_emit_store_flag (struct noce_if_info
*, rtx
, int, int);
714 static int noce_try_move (struct noce_if_info
*);
715 static int noce_try_store_flag (struct noce_if_info
*);
716 static int noce_try_addcc (struct noce_if_info
*);
717 static int noce_try_store_flag_constants (struct noce_if_info
*);
718 static int noce_try_store_flag_mask (struct noce_if_info
*);
719 static rtx
noce_emit_cmove (struct noce_if_info
*, rtx
, enum rtx_code
, rtx
,
721 static int noce_try_cmove (struct noce_if_info
*);
722 static int noce_try_cmove_arith (struct noce_if_info
*);
723 static rtx
noce_get_alt_condition (struct noce_if_info
*, rtx
, rtx
*);
724 static int noce_try_minmax (struct noce_if_info
*);
725 static int noce_try_abs (struct noce_if_info
*);
726 static int noce_try_sign_mask (struct noce_if_info
*);
728 /* Helper function for noce_try_store_flag*. */
731 noce_emit_store_flag (struct noce_if_info
*if_info
, rtx x
, int reversep
,
734 rtx cond
= if_info
->cond
;
738 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
739 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
741 /* If earliest == jump, or when the condition is complex, try to
742 build the store_flag insn directly. */
746 rtx set
= pc_set (if_info
->jump
);
747 cond
= XEXP (SET_SRC (set
), 0);
748 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
749 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
))
750 reversep
= !reversep
;
751 if (if_info
->then_else_reversed
)
752 reversep
= !reversep
;
756 code
= reversed_comparison_code (cond
, if_info
->jump
);
758 code
= GET_CODE (cond
);
760 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
761 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
765 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
767 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
770 tmp
= emit_insn (tmp
);
772 if (recog_memoized (tmp
) >= 0)
778 if_info
->cond_earliest
= if_info
->jump
;
786 /* Don't even try if the comparison operands or the mode of X are weird. */
787 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
790 return emit_store_flag (x
, code
, XEXP (cond
, 0),
791 XEXP (cond
, 1), VOIDmode
,
792 (code
== LTU
|| code
== LEU
793 || code
== GEU
|| code
== GTU
), normalize
);
796 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
797 X is the destination/target and Y is the value to copy. */
800 noce_emit_move_insn (rtx x
, rtx y
)
802 enum machine_mode outmode
;
806 if (GET_CODE (x
) != STRICT_LOW_PART
)
808 rtx seq
, insn
, target
;
812 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
813 otherwise construct a suitable SET pattern ourselves. */
814 insn
= (OBJECT_P (y
) || CONSTANT_P (y
) || GET_CODE (y
) == SUBREG
)
815 ? emit_move_insn (x
, y
)
816 : emit_insn (gen_rtx_SET (VOIDmode
, x
, y
));
820 if (recog_memoized (insn
) <= 0)
822 if (GET_CODE (x
) == ZERO_EXTRACT
)
824 rtx op
= XEXP (x
, 0);
825 unsigned HOST_WIDE_INT size
= INTVAL (XEXP (x
, 1));
826 unsigned HOST_WIDE_INT start
= INTVAL (XEXP (x
, 2));
828 /* store_bit_field expects START to be relative to
829 BYTES_BIG_ENDIAN and adjusts this value for machines with
830 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
831 invoke store_bit_field again it is necessary to have the START
832 value from the first call. */
833 if (BITS_BIG_ENDIAN
!= BYTES_BIG_ENDIAN
)
836 start
= BITS_PER_UNIT
- start
- size
;
839 gcc_assert (REG_P (op
));
840 start
= BITS_PER_WORD
- start
- size
;
844 gcc_assert (start
< (MEM_P (op
) ? BITS_PER_UNIT
: BITS_PER_WORD
));
845 store_bit_field (op
, size
, start
, GET_MODE (x
), y
);
849 switch (GET_RTX_CLASS (GET_CODE (y
)))
852 ot
= code_to_optab
[GET_CODE (y
)];
856 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
857 if (target
!= NULL_RTX
)
860 emit_move_insn (x
, target
);
869 ot
= code_to_optab
[GET_CODE (y
)];
873 target
= expand_binop (GET_MODE (y
), ot
,
874 XEXP (y
, 0), XEXP (y
, 1),
876 if (target
!= NULL_RTX
)
879 emit_move_insn (x
, target
);
896 inner
= XEXP (outer
, 0);
897 outmode
= GET_MODE (outer
);
898 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
899 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
, outmode
, y
);
902 /* Return sequence of instructions generated by if conversion. This
903 function calls end_sequence() to end the current stream, ensures
904 that are instructions are unshared, recognizable non-jump insns.
905 On failure, this function returns a NULL_RTX. */
908 end_ifcvt_sequence (struct noce_if_info
*if_info
)
911 rtx seq
= get_insns ();
913 set_used_flags (if_info
->x
);
914 set_used_flags (if_info
->cond
);
915 unshare_all_rtl_in_chain (seq
);
918 /* Make sure that all of the instructions emitted are recognizable,
919 and that we haven't introduced a new jump instruction.
920 As an exercise for the reader, build a general mechanism that
921 allows proper placement of required clobbers. */
922 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
924 || recog_memoized (insn
) == -1)
930 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
931 "if (a == b) x = a; else x = b" into "x = b". */
934 noce_try_move (struct noce_if_info
*if_info
)
936 rtx cond
= if_info
->cond
;
937 enum rtx_code code
= GET_CODE (cond
);
940 if (code
!= NE
&& code
!= EQ
)
943 /* This optimization isn't valid if either A or B could be a NaN
945 if (HONOR_NANS (GET_MODE (if_info
->x
))
946 || HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
949 /* Check whether the operands of the comparison are A and in
951 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
952 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
953 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
954 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
956 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
958 /* Avoid generating the move if the source is the destination. */
959 if (! rtx_equal_p (if_info
->x
, y
))
962 noce_emit_move_insn (if_info
->x
, y
);
963 seq
= end_ifcvt_sequence (if_info
);
967 emit_insn_before_setloc (seq
, if_info
->jump
,
968 INSN_LOCATOR (if_info
->insn_a
));
975 /* Convert "if (test) x = 1; else x = 0".
977 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
978 tried in noce_try_store_flag_constants after noce_try_cmove has had
979 a go at the conversion. */
982 noce_try_store_flag (struct noce_if_info
*if_info
)
987 if (CONST_INT_P (if_info
->b
)
988 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
989 && if_info
->a
== const0_rtx
)
991 else if (if_info
->b
== const0_rtx
992 && CONST_INT_P (if_info
->a
)
993 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
994 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1002 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
1005 if (target
!= if_info
->x
)
1006 noce_emit_move_insn (if_info
->x
, target
);
1008 seq
= end_ifcvt_sequence (if_info
);
1012 emit_insn_before_setloc (seq
, if_info
->jump
,
1013 INSN_LOCATOR (if_info
->insn_a
));
1023 /* Convert "if (test) x = a; else x = b", for A and B constant. */
1026 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
1030 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
1031 int normalize
, can_reverse
;
1032 enum machine_mode mode
;
1034 if (CONST_INT_P (if_info
->a
)
1035 && CONST_INT_P (if_info
->b
))
1037 mode
= GET_MODE (if_info
->x
);
1038 ifalse
= INTVAL (if_info
->a
);
1039 itrue
= INTVAL (if_info
->b
);
1041 /* Make sure we can represent the difference between the two values. */
1042 if ((itrue
- ifalse
> 0)
1043 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
1046 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
1048 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1052 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1054 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
1055 && (STORE_FLAG_VALUE
== 1
1056 || if_info
->branch_cost
>= 2))
1058 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
1059 && (STORE_FLAG_VALUE
== 1 || if_info
->branch_cost
>= 2))
1060 normalize
= 1, reversep
= 1;
1061 else if (itrue
== -1
1062 && (STORE_FLAG_VALUE
== -1
1063 || if_info
->branch_cost
>= 2))
1065 else if (ifalse
== -1 && can_reverse
1066 && (STORE_FLAG_VALUE
== -1 || if_info
->branch_cost
>= 2))
1067 normalize
= -1, reversep
= 1;
1068 else if ((if_info
->branch_cost
>= 2 && STORE_FLAG_VALUE
== -1)
1069 || if_info
->branch_cost
>= 3)
1076 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
1077 diff
= trunc_int_for_mode (-diff
, mode
);
1081 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
1088 /* if (test) x = 3; else x = 4;
1089 => x = 3 + (test == 0); */
1090 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1092 target
= expand_simple_binop (mode
,
1093 (diff
== STORE_FLAG_VALUE
1095 GEN_INT (ifalse
), target
, if_info
->x
, 0,
1099 /* if (test) x = 8; else x = 0;
1100 => x = (test != 0) << 3; */
1101 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
1103 target
= expand_simple_binop (mode
, ASHIFT
,
1104 target
, GEN_INT (tmp
), if_info
->x
, 0,
1108 /* if (test) x = -1; else x = b;
1109 => x = -(test != 0) | b; */
1110 else if (itrue
== -1)
1112 target
= expand_simple_binop (mode
, IOR
,
1113 target
, GEN_INT (ifalse
), if_info
->x
, 0,
1117 /* if (test) x = a; else x = b;
1118 => x = (-(test != 0) & (b - a)) + a; */
1121 target
= expand_simple_binop (mode
, AND
,
1122 target
, GEN_INT (diff
), if_info
->x
, 0,
1125 target
= expand_simple_binop (mode
, PLUS
,
1126 target
, GEN_INT (ifalse
),
1127 if_info
->x
, 0, OPTAB_WIDEN
);
1136 if (target
!= if_info
->x
)
1137 noce_emit_move_insn (if_info
->x
, target
);
1139 seq
= end_ifcvt_sequence (if_info
);
1143 emit_insn_before_setloc (seq
, if_info
->jump
,
1144 INSN_LOCATOR (if_info
->insn_a
));
1151 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1152 similarly for "foo--". */
1155 noce_try_addcc (struct noce_if_info
*if_info
)
1158 int subtract
, normalize
;
1160 if (GET_CODE (if_info
->a
) == PLUS
1161 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1162 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1165 rtx cond
= if_info
->cond
;
1166 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1168 /* First try to use addcc pattern. */
1169 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1170 && general_operand (XEXP (cond
, 1), VOIDmode
))
1173 target
= emit_conditional_add (if_info
->x
, code
,
1178 XEXP (if_info
->a
, 1),
1179 GET_MODE (if_info
->x
),
1180 (code
== LTU
|| code
== GEU
1181 || code
== LEU
|| code
== GTU
));
1184 if (target
!= if_info
->x
)
1185 noce_emit_move_insn (if_info
->x
, target
);
1187 seq
= end_ifcvt_sequence (if_info
);
1191 emit_insn_before_setloc (seq
, if_info
->jump
,
1192 INSN_LOCATOR (if_info
->insn_a
));
1198 /* If that fails, construct conditional increment or decrement using
1200 if (if_info
->branch_cost
>= 2
1201 && (XEXP (if_info
->a
, 1) == const1_rtx
1202 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1205 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1206 subtract
= 0, normalize
= 0;
1207 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1208 subtract
= 1, normalize
= 0;
1210 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1213 target
= noce_emit_store_flag (if_info
,
1214 gen_reg_rtx (GET_MODE (if_info
->x
)),
1218 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1219 subtract
? MINUS
: PLUS
,
1220 if_info
->b
, target
, if_info
->x
,
1224 if (target
!= if_info
->x
)
1225 noce_emit_move_insn (if_info
->x
, target
);
1227 seq
= end_ifcvt_sequence (if_info
);
1231 emit_insn_before_setloc (seq
, if_info
->jump
,
1232 INSN_LOCATOR (if_info
->insn_a
));
1242 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1245 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1251 if ((if_info
->branch_cost
>= 2
1252 || STORE_FLAG_VALUE
== -1)
1253 && ((if_info
->a
== const0_rtx
1254 && rtx_equal_p (if_info
->b
, if_info
->x
))
1255 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1258 && if_info
->b
== const0_rtx
1259 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1262 target
= noce_emit_store_flag (if_info
,
1263 gen_reg_rtx (GET_MODE (if_info
->x
)),
1266 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1268 target
, if_info
->x
, 0,
1273 if (target
!= if_info
->x
)
1274 noce_emit_move_insn (if_info
->x
, target
);
1276 seq
= end_ifcvt_sequence (if_info
);
1280 emit_insn_before_setloc (seq
, if_info
->jump
,
1281 INSN_LOCATOR (if_info
->insn_a
));
1291 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1294 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1295 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1297 /* If earliest == jump, try to build the cmove insn directly.
1298 This is helpful when combine has created some complex condition
1299 (like for alpha's cmovlbs) that we can't hope to regenerate
1300 through the normal interface. */
1302 if (if_info
->cond_earliest
== if_info
->jump
)
1306 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1307 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
1308 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
1311 tmp
= emit_insn (tmp
);
1313 if (recog_memoized (tmp
) >= 0)
1325 /* Don't even try if the comparison operands are weird. */
1326 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1327 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1330 #if HAVE_conditional_move
1331 return emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1332 vtrue
, vfalse
, GET_MODE (x
),
1333 (code
== LTU
|| code
== GEU
1334 || code
== LEU
|| code
== GTU
));
1336 /* We'll never get here, as noce_process_if_block doesn't call the
1337 functions involved. Ifdef code, however, should be discouraged
1338 because it leads to typos in the code not selected. However,
1339 emit_conditional_move won't exist either. */
1344 /* Try only simple constants and registers here. More complex cases
1345 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1346 has had a go at it. */
1349 noce_try_cmove (struct noce_if_info
*if_info
)
1354 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1355 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1359 code
= GET_CODE (if_info
->cond
);
1360 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1361 XEXP (if_info
->cond
, 0),
1362 XEXP (if_info
->cond
, 1),
1363 if_info
->a
, if_info
->b
);
1367 if (target
!= if_info
->x
)
1368 noce_emit_move_insn (if_info
->x
, target
);
1370 seq
= end_ifcvt_sequence (if_info
);
1374 emit_insn_before_setloc (seq
, if_info
->jump
,
1375 INSN_LOCATOR (if_info
->insn_a
));
1388 /* Try more complex cases involving conditional_move. */
1391 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1403 /* A conditional move from two memory sources is equivalent to a
1404 conditional on their addresses followed by a load. Don't do this
1405 early because it'll screw alias analysis. Note that we've
1406 already checked for no side effects. */
1407 /* ??? FIXME: Magic number 5. */
1408 if (cse_not_expected
1409 && MEM_P (a
) && MEM_P (b
)
1410 && MEM_ADDR_SPACE (a
) == MEM_ADDR_SPACE (b
)
1411 && if_info
->branch_cost
>= 5)
1413 enum machine_mode address_mode
1414 = targetm
.addr_space
.address_mode (MEM_ADDR_SPACE (a
));
1418 x
= gen_reg_rtx (address_mode
);
1422 /* ??? We could handle this if we knew that a load from A or B could
1423 not fault. This is also true if we've already loaded
1424 from the address along the path from ENTRY. */
1425 else if (may_trap_p (a
) || may_trap_p (b
))
1428 /* if (test) x = a + b; else x = c - d;
1435 code
= GET_CODE (if_info
->cond
);
1436 insn_a
= if_info
->insn_a
;
1437 insn_b
= if_info
->insn_b
;
1439 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1440 if insn_rtx_cost can't be estimated. */
1444 = insn_rtx_cost (PATTERN (insn_a
),
1445 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a
)));
1446 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1455 += insn_rtx_cost (PATTERN (insn_b
),
1456 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b
)));
1457 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1461 /* Possibly rearrange operands to make things come out more natural. */
1462 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1465 if (rtx_equal_p (b
, x
))
1467 else if (general_operand (b
, GET_MODE (b
)))
1472 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1473 tmp
= a
, a
= b
, b
= tmp
;
1474 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1483 /* If either operand is complex, load it into a register first.
1484 The best way to do this is to copy the original insn. In this
1485 way we preserve any clobbers etc that the insn may have had.
1486 This is of course not possible in the IS_MEM case. */
1487 if (! general_operand (a
, GET_MODE (a
)))
1493 tmp
= gen_reg_rtx (GET_MODE (a
));
1494 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1497 goto end_seq_and_fail
;
1500 a
= gen_reg_rtx (GET_MODE (a
));
1501 tmp
= copy_rtx (insn_a
);
1502 set
= single_set (tmp
);
1504 tmp
= emit_insn (PATTERN (tmp
));
1506 if (recog_memoized (tmp
) < 0)
1507 goto end_seq_and_fail
;
1509 if (! general_operand (b
, GET_MODE (b
)))
1515 tmp
= gen_reg_rtx (GET_MODE (b
));
1516 tmp
= gen_rtx_SET (VOIDmode
, tmp
, b
);
1519 goto end_seq_and_fail
;
1522 b
= gen_reg_rtx (GET_MODE (b
));
1523 tmp
= copy_rtx (insn_b
);
1524 set
= single_set (tmp
);
1526 tmp
= PATTERN (tmp
);
1529 /* If insn to set up A clobbers any registers B depends on, try to
1530 swap insn that sets up A with the one that sets up B. If even
1531 that doesn't help, punt. */
1532 last
= get_last_insn ();
1533 if (last
&& modified_in_p (orig_b
, last
))
1535 tmp
= emit_insn_before (tmp
, get_insns ());
1536 if (modified_in_p (orig_a
, tmp
))
1537 goto end_seq_and_fail
;
1540 tmp
= emit_insn (tmp
);
1542 if (recog_memoized (tmp
) < 0)
1543 goto end_seq_and_fail
;
1546 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1547 XEXP (if_info
->cond
, 1), a
, b
);
1550 goto end_seq_and_fail
;
1552 /* If we're handling a memory for above, emit the load now. */
1555 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1557 /* Copy over flags as appropriate. */
1558 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1559 MEM_VOLATILE_P (tmp
) = 1;
1560 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1561 MEM_IN_STRUCT_P (tmp
) = 1;
1562 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1563 MEM_SCALAR_P (tmp
) = 1;
1564 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1565 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1567 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1569 gcc_assert (MEM_ADDR_SPACE (if_info
->a
) == MEM_ADDR_SPACE (if_info
->b
));
1570 set_mem_addr_space (tmp
, MEM_ADDR_SPACE (if_info
->a
));
1572 noce_emit_move_insn (if_info
->x
, tmp
);
1574 else if (target
!= x
)
1575 noce_emit_move_insn (x
, target
);
1577 tmp
= end_ifcvt_sequence (if_info
);
1581 emit_insn_before_setloc (tmp
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1589 /* For most cases, the simplified condition we found is the best
1590 choice, but this is not the case for the min/max/abs transforms.
1591 For these we wish to know that it is A or B in the condition. */
1594 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1597 rtx cond
, set
, insn
;
1600 /* If target is already mentioned in the known condition, return it. */
1601 if (reg_mentioned_p (target
, if_info
->cond
))
1603 *earliest
= if_info
->cond_earliest
;
1604 return if_info
->cond
;
1607 set
= pc_set (if_info
->jump
);
1608 cond
= XEXP (SET_SRC (set
), 0);
1610 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1611 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1612 if (if_info
->then_else_reversed
)
1615 /* If we're looking for a constant, try to make the conditional
1616 have that constant in it. There are two reasons why it may
1617 not have the constant we want:
1619 1. GCC may have needed to put the constant in a register, because
1620 the target can't compare directly against that constant. For
1621 this case, we look for a SET immediately before the comparison
1622 that puts a constant in that register.
1624 2. GCC may have canonicalized the conditional, for example
1625 replacing "if x < 4" with "if x <= 3". We can undo that (or
1626 make equivalent types of changes) to get the constants we need
1627 if they're off by one in the right direction. */
1629 if (CONST_INT_P (target
))
1631 enum rtx_code code
= GET_CODE (if_info
->cond
);
1632 rtx op_a
= XEXP (if_info
->cond
, 0);
1633 rtx op_b
= XEXP (if_info
->cond
, 1);
1636 /* First, look to see if we put a constant in a register. */
1637 prev_insn
= prev_nonnote_insn (if_info
->cond_earliest
);
1639 && BLOCK_FOR_INSN (prev_insn
)
1640 == BLOCK_FOR_INSN (if_info
->cond_earliest
)
1641 && INSN_P (prev_insn
)
1642 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1644 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1646 src
= SET_SRC (PATTERN (prev_insn
));
1647 if (CONST_INT_P (src
))
1649 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1651 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1654 if (CONST_INT_P (op_a
))
1659 code
= swap_condition (code
);
1664 /* Now, look to see if we can get the right constant by
1665 adjusting the conditional. */
1666 if (CONST_INT_P (op_b
))
1668 HOST_WIDE_INT desired_val
= INTVAL (target
);
1669 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1674 if (actual_val
== desired_val
+ 1)
1677 op_b
= GEN_INT (desired_val
);
1681 if (actual_val
== desired_val
- 1)
1684 op_b
= GEN_INT (desired_val
);
1688 if (actual_val
== desired_val
- 1)
1691 op_b
= GEN_INT (desired_val
);
1695 if (actual_val
== desired_val
+ 1)
1698 op_b
= GEN_INT (desired_val
);
1706 /* If we made any changes, generate a new conditional that is
1707 equivalent to what we started with, but has the right
1709 if (code
!= GET_CODE (if_info
->cond
)
1710 || op_a
!= XEXP (if_info
->cond
, 0)
1711 || op_b
!= XEXP (if_info
->cond
, 1))
1713 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1714 *earliest
= if_info
->cond_earliest
;
1719 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1720 earliest
, target
, false, true);
1721 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1724 /* We almost certainly searched back to a different place.
1725 Need to re-verify correct lifetimes. */
1727 /* X may not be mentioned in the range (cond_earliest, jump]. */
1728 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1729 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1732 /* A and B may not be modified in the range [cond_earliest, jump). */
1733 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1735 && (modified_in_p (if_info
->a
, insn
)
1736 || modified_in_p (if_info
->b
, insn
)))
1742 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1745 noce_try_minmax (struct noce_if_info
*if_info
)
1747 rtx cond
, earliest
, target
, seq
;
1748 enum rtx_code code
, op
;
1751 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1752 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1753 to get the target to tell us... */
1754 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1755 || HONOR_NANS (GET_MODE (if_info
->x
)))
1758 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1762 /* Verify the condition is of the form we expect, and canonicalize
1763 the comparison code. */
1764 code
= GET_CODE (cond
);
1765 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1767 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1770 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1772 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1774 code
= swap_condition (code
);
1779 /* Determine what sort of operation this is. Note that the code is for
1780 a taken branch, so the code->operation mapping appears backwards. */
1813 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1814 if_info
->a
, if_info
->b
,
1815 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1821 if (target
!= if_info
->x
)
1822 noce_emit_move_insn (if_info
->x
, target
);
1824 seq
= end_ifcvt_sequence (if_info
);
1828 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1829 if_info
->cond
= cond
;
1830 if_info
->cond_earliest
= earliest
;
1835 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
1836 "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
1840 noce_try_abs (struct noce_if_info
*if_info
)
1842 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1844 bool one_cmpl
= false;
1846 /* Reject modes with signed zeros. */
1847 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
1850 /* Recognize A and B as constituting an ABS or NABS. The canonical
1851 form is a branch around the negation, taken when the object is the
1852 first operand of a comparison against 0 that evaluates to true. */
1855 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1857 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1859 c
= a
; a
= b
; b
= c
;
1862 else if (GET_CODE (a
) == NOT
&& rtx_equal_p (XEXP (a
, 0), b
))
1867 else if (GET_CODE (b
) == NOT
&& rtx_equal_p (XEXP (b
, 0), a
))
1869 c
= a
; a
= b
; b
= c
;
1876 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1880 /* Verify the condition is of the form we expect. */
1881 if (rtx_equal_p (XEXP (cond
, 0), b
))
1883 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1891 /* Verify that C is zero. Search one step backward for a
1892 REG_EQUAL note or a simple source if necessary. */
1895 rtx set
, insn
= prev_nonnote_insn (earliest
);
1897 && BLOCK_FOR_INSN (insn
) == BLOCK_FOR_INSN (earliest
)
1898 && (set
= single_set (insn
))
1899 && rtx_equal_p (SET_DEST (set
), c
))
1901 rtx note
= find_reg_equal_equiv_note (insn
);
1911 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
1912 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
1913 c
= get_pool_constant (XEXP (c
, 0));
1915 /* Work around funny ideas get_condition has wrt canonicalization.
1916 Note that these rtx constants are known to be CONST_INT, and
1917 therefore imply integer comparisons. */
1918 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
1920 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
1922 else if (c
!= CONST0_RTX (GET_MODE (b
)))
1925 /* Determine what sort of operation this is. */
1926 switch (GET_CODE (cond
))
1945 target
= expand_one_cmpl_abs_nojump (GET_MODE (if_info
->x
), b
,
1948 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
1950 /* ??? It's a quandary whether cmove would be better here, especially
1951 for integers. Perhaps combine will clean things up. */
1952 if (target
&& negate
)
1955 target
= expand_simple_unop (GET_MODE (target
), NOT
, target
,
1958 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
,
1968 if (target
!= if_info
->x
)
1969 noce_emit_move_insn (if_info
->x
, target
);
1971 seq
= end_ifcvt_sequence (if_info
);
1975 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1976 if_info
->cond
= cond
;
1977 if_info
->cond_earliest
= earliest
;
1982 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
1985 noce_try_sign_mask (struct noce_if_info
*if_info
)
1987 rtx cond
, t
, m
, c
, seq
;
1988 enum machine_mode mode
;
1990 bool t_unconditional
;
1992 cond
= if_info
->cond
;
1993 code
= GET_CODE (cond
);
1998 if (if_info
->a
== const0_rtx
)
2000 if ((code
== LT
&& c
== const0_rtx
)
2001 || (code
== LE
&& c
== constm1_rtx
))
2004 else if (if_info
->b
== const0_rtx
)
2006 if ((code
== GE
&& c
== const0_rtx
)
2007 || (code
== GT
&& c
== constm1_rtx
))
2011 if (! t
|| side_effects_p (t
))
2014 /* We currently don't handle different modes. */
2015 mode
= GET_MODE (t
);
2016 if (GET_MODE (m
) != mode
)
2019 /* This is only profitable if T is unconditionally executed/evaluated in the
2020 original insn sequence or T is cheap. The former happens if B is the
2021 non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
2022 INSN_B which can happen for e.g. conditional stores to memory. For the
2023 cost computation use the block TEST_BB where the evaluation will end up
2024 after the transformation. */
2027 && (if_info
->insn_b
== NULL_RTX
2028 || BLOCK_FOR_INSN (if_info
->insn_b
) == if_info
->test_bb
));
2029 if (!(t_unconditional
2030 || (rtx_cost (t
, SET
, optimize_bb_for_speed_p (if_info
->test_bb
))
2031 < COSTS_N_INSNS (2))))
2035 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
2036 "(signed) m >> 31" directly. This benefits targets with specialized
2037 insns to obtain the signmask, but still uses ashr_optab otherwise. */
2038 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
2039 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
2048 noce_emit_move_insn (if_info
->x
, t
);
2050 seq
= end_ifcvt_sequence (if_info
);
2054 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
2059 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
2063 noce_try_bitop (struct noce_if_info
*if_info
)
2065 rtx cond
, x
, a
, result
, seq
;
2066 enum machine_mode mode
;
2071 cond
= if_info
->cond
;
2072 code
= GET_CODE (cond
);
2074 /* Check for no else condition. */
2075 if (! rtx_equal_p (x
, if_info
->b
))
2078 /* Check for a suitable condition. */
2079 if (code
!= NE
&& code
!= EQ
)
2081 if (XEXP (cond
, 1) != const0_rtx
)
2083 cond
= XEXP (cond
, 0);
2085 /* ??? We could also handle AND here. */
2086 if (GET_CODE (cond
) == ZERO_EXTRACT
)
2088 if (XEXP (cond
, 1) != const1_rtx
2089 || !CONST_INT_P (XEXP (cond
, 2))
2090 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
2092 bitnum
= INTVAL (XEXP (cond
, 2));
2093 mode
= GET_MODE (x
);
2094 if (BITS_BIG_ENDIAN
)
2095 bitnum
= GET_MODE_BITSIZE (mode
) - 1 - bitnum
;
2096 if (bitnum
< 0 || bitnum
>= HOST_BITS_PER_WIDE_INT
)
2103 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
2105 /* Check for "if (X & C) x = x op C". */
2106 if (! rtx_equal_p (x
, XEXP (a
, 0))
2107 || !CONST_INT_P (XEXP (a
, 1))
2108 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2109 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
2112 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
2113 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
2114 if (GET_CODE (a
) == IOR
)
2115 result
= (code
== NE
) ? a
: NULL_RTX
;
2116 else if (code
== NE
)
2118 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
2119 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
2120 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
2124 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2125 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
2126 result
= simplify_gen_binary (AND
, mode
, x
, result
);
2129 else if (GET_CODE (a
) == AND
)
2131 /* Check for "if (X & C) x &= ~C". */
2132 if (! rtx_equal_p (x
, XEXP (a
, 0))
2133 || !CONST_INT_P (XEXP (a
, 1))
2134 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2135 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
2138 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2139 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2140 result
= (code
== EQ
) ? a
: NULL_RTX
;
2148 noce_emit_move_insn (x
, result
);
2149 seq
= end_ifcvt_sequence (if_info
);
2153 emit_insn_before_setloc (seq
, if_info
->jump
,
2154 INSN_LOCATOR (if_info
->insn_a
));
2160 /* Similar to get_condition, only the resulting condition must be
2161 valid at JUMP, instead of at EARLIEST.
2163 If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
2164 THEN block of the caller, and we have to reverse the condition. */
2167 noce_get_condition (rtx jump
, rtx
*earliest
, bool then_else_reversed
)
2172 if (! any_condjump_p (jump
))
2175 set
= pc_set (jump
);
2177 /* If this branches to JUMP_LABEL when the condition is false,
2178 reverse the condition. */
2179 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
2180 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
2182 /* We may have to reverse because the caller's if block is not canonical,
2183 i.e. the THEN block isn't the fallthrough block for the TEST block
2184 (see find_if_header). */
2185 if (then_else_reversed
)
2188 /* If the condition variable is a register and is MODE_INT, accept it. */
2190 cond
= XEXP (SET_SRC (set
), 0);
2191 tmp
= XEXP (cond
, 0);
2192 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
)
2197 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
2198 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2202 /* Otherwise, fall back on canonicalize_condition to do the dirty
2203 work of manipulating MODE_CC values and COMPARE rtx codes. */
2204 return canonicalize_condition (jump
, cond
, reverse
, earliest
,
2205 NULL_RTX
, false, true);
2208 /* Return true if OP is ok for if-then-else processing. */
2211 noce_operand_ok (const_rtx op
)
2213 /* We special-case memories, so handle any of them with
2214 no address side effects. */
2216 return ! side_effects_p (XEXP (op
, 0));
2218 if (side_effects_p (op
))
2221 return ! may_trap_p (op
);
2224 /* Return true if a write into MEM may trap or fault. */
2227 noce_mem_write_may_trap_or_fault_p (const_rtx mem
)
2231 if (MEM_READONLY_P (mem
))
2234 if (may_trap_or_fault_p (mem
))
2237 addr
= XEXP (mem
, 0);
2239 /* Call target hook to avoid the effects of -fpic etc.... */
2240 addr
= targetm
.delegitimize_address (addr
);
2243 switch (GET_CODE (addr
))
2251 addr
= XEXP (addr
, 0);
2255 addr
= XEXP (addr
, 1);
2258 if (CONST_INT_P (XEXP (addr
, 1)))
2259 addr
= XEXP (addr
, 0);
2266 if (SYMBOL_REF_DECL (addr
)
2267 && decl_readonly_section (SYMBOL_REF_DECL (addr
), 0))
2277 /* Return whether we can use store speculation for MEM. TOP_BB is the
2278 basic block above the conditional block where we are considering
2279 doing the speculative store. We look for whether MEM is set
2280 unconditionally later in the function. */
2283 noce_can_store_speculate_p (basic_block top_bb
, const_rtx mem
)
2285 basic_block dominator
;
2287 for (dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, top_bb
);
2289 dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, dominator
))
2293 FOR_BB_INSNS (dominator
, insn
)
2295 /* If we see something that might be a memory barrier, we
2296 have to stop looking. Even if the MEM is set later in
2297 the function, we still don't want to set it
2298 unconditionally before the barrier. */
2300 && (volatile_insn_p (PATTERN (insn
))
2301 || (CALL_P (insn
) && (!RTL_CONST_CALL_P (insn
)))))
2304 if (memory_modified_in_insn_p (mem
, insn
))
2306 if (modified_in_p (XEXP (mem
, 0), insn
))
2315 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2316 it without using conditional execution. Return TRUE if we were successful
2317 at converting the block. */
2320 noce_process_if_block (struct noce_if_info
*if_info
)
2322 basic_block test_bb
= if_info
->test_bb
; /* test block */
2323 basic_block then_bb
= if_info
->then_bb
; /* THEN */
2324 basic_block else_bb
= if_info
->else_bb
; /* ELSE or NULL */
2325 basic_block join_bb
= if_info
->join_bb
; /* JOIN */
2326 rtx jump
= if_info
->jump
;
2327 rtx cond
= if_info
->cond
;
2330 rtx orig_x
, x
, a
, b
;
2332 /* We're looking for patterns of the form
2334 (1) if (...) x = a; else x = b;
2335 (2) x = b; if (...) x = a;
2336 (3) if (...) x = a; // as if with an initial x = x.
2338 The later patterns require jumps to be more expensive.
2340 ??? For future expansion, look for multiple X in such patterns. */
2342 /* Look for one of the potential sets. */
2343 insn_a
= first_active_insn (then_bb
);
2345 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2346 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2349 x
= SET_DEST (set_a
);
2350 a
= SET_SRC (set_a
);
2352 /* Look for the other potential set. Make sure we've got equivalent
2354 /* ??? This is overconservative. Storing to two different mems is
2355 as easy as conditionally computing the address. Storing to a
2356 single mem merely requires a scratch memory to use as one of the
2357 destination addresses; often the memory immediately below the
2358 stack pointer is available for this. */
2362 insn_b
= first_active_insn (else_bb
);
2364 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2365 || (set_b
= single_set (insn_b
)) == NULL_RTX
2366 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
2371 insn_b
= prev_nonnote_nondebug_insn (if_info
->cond_earliest
);
2372 /* We're going to be moving the evaluation of B down from above
2373 COND_EARLIEST to JUMP. Make sure the relevant data is still
2376 || BLOCK_FOR_INSN (insn_b
) != BLOCK_FOR_INSN (if_info
->cond_earliest
)
2377 || !NONJUMP_INSN_P (insn_b
)
2378 || (set_b
= single_set (insn_b
)) == NULL_RTX
2379 || ! rtx_equal_p (x
, SET_DEST (set_b
))
2380 || ! noce_operand_ok (SET_SRC (set_b
))
2381 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2382 || modified_between_p (SET_SRC (set_b
), insn_b
, jump
)
2383 /* Likewise with X. In particular this can happen when
2384 noce_get_condition looks farther back in the instruction
2385 stream than one might expect. */
2386 || reg_overlap_mentioned_p (x
, cond
)
2387 || reg_overlap_mentioned_p (x
, a
)
2388 || modified_between_p (x
, insn_b
, jump
))
2389 insn_b
= set_b
= NULL_RTX
;
2392 /* If x has side effects then only the if-then-else form is safe to
2393 convert. But even in that case we would need to restore any notes
2394 (such as REG_INC) at then end. That can be tricky if
2395 noce_emit_move_insn expands to more than one insn, so disable the
2396 optimization entirely for now if there are side effects. */
2397 if (side_effects_p (x
))
2400 b
= (set_b
? SET_SRC (set_b
) : x
);
2402 /* Only operate on register destinations, and even then avoid extending
2403 the lifetime of hard registers on small register class machines. */
2406 || (HARD_REGISTER_P (x
)
2407 && targetm
.small_register_classes_for_mode_p (GET_MODE (x
))))
2409 if (GET_MODE (x
) == BLKmode
)
2412 if (GET_CODE (x
) == ZERO_EXTRACT
2413 && (!CONST_INT_P (XEXP (x
, 1))
2414 || !CONST_INT_P (XEXP (x
, 2))))
2417 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2418 ? XEXP (x
, 0) : x
));
2421 /* Don't operate on sources that may trap or are volatile. */
2422 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2426 /* Set up the info block for our subroutines. */
2427 if_info
->insn_a
= insn_a
;
2428 if_info
->insn_b
= insn_b
;
2433 /* Try optimizations in some approximation of a useful order. */
2434 /* ??? Should first look to see if X is live incoming at all. If it
2435 isn't, we don't need anything but an unconditional set. */
2437 /* Look and see if A and B are really the same. Avoid creating silly
2438 cmove constructs that no one will fix up later. */
2439 if (rtx_equal_p (a
, b
))
2441 /* If we have an INSN_B, we don't have to create any new rtl. Just
2442 move the instruction that we already have. If we don't have an
2443 INSN_B, that means that A == X, and we've got a noop move. In
2444 that case don't do anything and let the code below delete INSN_A. */
2445 if (insn_b
&& else_bb
)
2449 if (else_bb
&& insn_b
== BB_END (else_bb
))
2450 BB_END (else_bb
) = PREV_INSN (insn_b
);
2451 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2453 /* If there was a REG_EQUAL note, delete it since it may have been
2454 true due to this insn being after a jump. */
2455 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2456 remove_note (insn_b
, note
);
2460 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2461 x must be executed twice. */
2462 else if (insn_b
&& side_effects_p (orig_x
))
2469 if (!set_b
&& MEM_P (orig_x
))
2471 /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
2472 for optimizations if writing to x may trap or fault,
2473 i.e. it's a memory other than a static var or a stack slot,
2474 is misaligned on strict aligned machines or is read-only. If
2475 x is a read-only memory, then the program is valid only if we
2476 avoid the store into it. If there are stores on both the
2477 THEN and ELSE arms, then we can go ahead with the conversion;
2478 either the program is broken, or the condition is always
2479 false such that the other memory is selected. */
2480 if (noce_mem_write_may_trap_or_fault_p (orig_x
))
2483 /* Avoid store speculation: given "if (...) x = a" where x is a
2484 MEM, we only want to do the store if x is always set
2485 somewhere in the function. This avoids cases like
2486 if (pthread_mutex_trylock(mutex))
2488 where we only want global_variable to be changed if the mutex
2489 is held. FIXME: This should ideally be expressed directly in
2491 if (!noce_can_store_speculate_p (test_bb
, orig_x
))
2495 if (noce_try_move (if_info
))
2497 if (noce_try_store_flag (if_info
))
2499 if (noce_try_bitop (if_info
))
2501 if (noce_try_minmax (if_info
))
2503 if (noce_try_abs (if_info
))
2505 if (HAVE_conditional_move
2506 && noce_try_cmove (if_info
))
2508 if (! targetm
.have_conditional_execution ())
2510 if (noce_try_store_flag_constants (if_info
))
2512 if (noce_try_addcc (if_info
))
2514 if (noce_try_store_flag_mask (if_info
))
2516 if (HAVE_conditional_move
2517 && noce_try_cmove_arith (if_info
))
2519 if (noce_try_sign_mask (if_info
))
2523 if (!else_bb
&& set_b
)
2525 insn_b
= set_b
= NULL_RTX
;
2534 /* If we used a temporary, fix it up now. */
2540 noce_emit_move_insn (orig_x
, x
);
2542 set_used_flags (orig_x
);
2543 unshare_all_rtl_in_chain (seq
);
2546 emit_insn_before_setloc (seq
, BB_END (test_bb
), INSN_LOCATOR (insn_a
));
2549 /* The original THEN and ELSE blocks may now be removed. The test block
2550 must now jump to the join block. If the test block and the join block
2551 can be merged, do so. */
2554 delete_basic_block (else_bb
);
2558 remove_edge (find_edge (test_bb
, join_bb
));
2560 remove_edge (find_edge (then_bb
, join_bb
));
2561 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2562 delete_basic_block (then_bb
);
2565 if (can_merge_blocks_p (test_bb
, join_bb
))
2567 merge_blocks (test_bb
, join_bb
);
2571 num_updated_if_blocks
++;
2575 /* Check whether a block is suitable for conditional move conversion.
2576 Every insn must be a simple set of a register to a constant or a
2577 register. For each assignment, store the value in the array VALS,
2578 indexed by register number, then store the register number in
2579 REGS. COND is the condition we will test. */
2582 check_cond_move_block (basic_block bb
, rtx
*vals
, VEC (int, heap
) **regs
,
2587 /* We can only handle simple jumps at the end of the basic block.
2588 It is almost impossible to update the CFG otherwise. */
2590 if (JUMP_P (insn
) && !onlyjump_p (insn
))
2593 FOR_BB_INSNS (bb
, insn
)
2597 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2599 set
= single_set (insn
);
2603 dest
= SET_DEST (set
);
2604 src
= SET_SRC (set
);
2606 || (HARD_REGISTER_P (dest
)
2607 && targetm
.small_register_classes_for_mode_p (GET_MODE (dest
))))
2610 if (!CONSTANT_P (src
) && !register_operand (src
, VOIDmode
))
2613 if (side_effects_p (src
) || side_effects_p (dest
))
2616 if (may_trap_p (src
) || may_trap_p (dest
))
2619 /* Don't try to handle this if the source register was
2620 modified earlier in the block. */
2622 && vals
[REGNO (src
)] != NULL
)
2623 || (GET_CODE (src
) == SUBREG
&& REG_P (SUBREG_REG (src
))
2624 && vals
[REGNO (SUBREG_REG (src
))] != NULL
))
2627 /* Don't try to handle this if the destination register was
2628 modified earlier in the block. */
2629 if (vals
[REGNO (dest
)] != NULL
)
2632 /* Don't try to handle this if the condition uses the
2633 destination register. */
2634 if (reg_overlap_mentioned_p (dest
, cond
))
2637 /* Don't try to handle this if the source register is modified
2638 later in the block. */
2639 if (!CONSTANT_P (src
)
2640 && modified_between_p (src
, insn
, NEXT_INSN (BB_END (bb
))))
2643 vals
[REGNO (dest
)] = src
;
2645 VEC_safe_push (int, heap
, *regs
, REGNO (dest
));
2651 /* Given a basic block BB suitable for conditional move conversion,
2652 a condition COND, and arrays THEN_VALS and ELSE_VALS containing the
2653 register values depending on COND, emit the insns in the block as
2654 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2655 processed. The caller has started a sequence for the conversion.
2656 Return true if successful, false if something goes wrong. */
2659 cond_move_convert_if_block (struct noce_if_info
*if_infop
,
2660 basic_block bb
, rtx cond
,
2661 rtx
*then_vals
, rtx
*else_vals
,
2665 rtx insn
, cond_arg0
, cond_arg1
;
2667 code
= GET_CODE (cond
);
2668 cond_arg0
= XEXP (cond
, 0);
2669 cond_arg1
= XEXP (cond
, 1);
2671 FOR_BB_INSNS (bb
, insn
)
2673 rtx set
, target
, dest
, t
, e
;
2676 /* ??? Maybe emit conditional debug insn? */
2677 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2679 set
= single_set (insn
);
2680 gcc_assert (set
&& REG_P (SET_DEST (set
)));
2682 dest
= SET_DEST (set
);
2683 regno
= REGNO (dest
);
2685 t
= then_vals
[regno
];
2686 e
= else_vals
[regno
];
2690 /* If this register was set in the then block, we already
2691 handled this case there. */
2704 target
= noce_emit_cmove (if_infop
, dest
, code
, cond_arg0
, cond_arg1
,
2710 noce_emit_move_insn (dest
, target
);
2716 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2717 it using only conditional moves. Return TRUE if we were successful at
2718 converting the block. */
2721 cond_move_process_if_block (struct noce_if_info
*if_info
)
2723 basic_block test_bb
= if_info
->test_bb
;
2724 basic_block then_bb
= if_info
->then_bb
;
2725 basic_block else_bb
= if_info
->else_bb
;
2726 basic_block join_bb
= if_info
->join_bb
;
2727 rtx jump
= if_info
->jump
;
2728 rtx cond
= if_info
->cond
;
2730 int max_reg
, size
, c
, reg
;
2733 VEC (int, heap
) *then_regs
= NULL
;
2734 VEC (int, heap
) *else_regs
= NULL
;
2737 /* Build a mapping for each block to the value used for each
2739 max_reg
= max_reg_num ();
2740 size
= (max_reg
+ 1) * sizeof (rtx
);
2741 then_vals
= (rtx
*) alloca (size
);
2742 else_vals
= (rtx
*) alloca (size
);
2743 memset (then_vals
, 0, size
);
2744 memset (else_vals
, 0, size
);
2746 /* Make sure the blocks are suitable. */
2747 if (!check_cond_move_block (then_bb
, then_vals
, &then_regs
, cond
)
2749 && !check_cond_move_block (else_bb
, else_vals
, &else_regs
, cond
)))
2751 VEC_free (int, heap
, then_regs
);
2752 VEC_free (int, heap
, else_regs
);
2756 /* Make sure the blocks can be used together. If the same register
2757 is set in both blocks, and is not set to a constant in both
2758 cases, then both blocks must set it to the same register. We
2759 have already verified that if it is set to a register, that the
2760 source register does not change after the assignment. Also count
2761 the number of registers set in only one of the blocks. */
2763 for (i
= 0; VEC_iterate (int, then_regs
, i
, reg
); i
++)
2765 if (!then_vals
[reg
] && !else_vals
[reg
])
2768 if (!else_vals
[reg
])
2772 if (!CONSTANT_P (then_vals
[reg
])
2773 && !CONSTANT_P (else_vals
[reg
])
2774 && !rtx_equal_p (then_vals
[reg
], else_vals
[reg
]))
2776 VEC_free (int, heap
, then_regs
);
2777 VEC_free (int, heap
, else_regs
);
2783 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
2784 for (i
= 0; VEC_iterate (int, else_regs
, i
, reg
); ++i
)
2785 if (!then_vals
[reg
])
2788 /* Make sure it is reasonable to convert this block. What matters
2789 is the number of assignments currently made in only one of the
2790 branches, since if we convert we are going to always execute
2792 if (c
> MAX_CONDITIONAL_EXECUTE
)
2794 VEC_free (int, heap
, then_regs
);
2795 VEC_free (int, heap
, else_regs
);
2799 /* Try to emit the conditional moves. First do the then block,
2800 then do anything left in the else blocks. */
2802 if (!cond_move_convert_if_block (if_info
, then_bb
, cond
,
2803 then_vals
, else_vals
, false)
2805 && !cond_move_convert_if_block (if_info
, else_bb
, cond
,
2806 then_vals
, else_vals
, true)))
2809 VEC_free (int, heap
, then_regs
);
2810 VEC_free (int, heap
, else_regs
);
2813 seq
= end_ifcvt_sequence (if_info
);
2816 VEC_free (int, heap
, then_regs
);
2817 VEC_free (int, heap
, else_regs
);
2821 loc_insn
= first_active_insn (then_bb
);
2824 loc_insn
= first_active_insn (else_bb
);
2825 gcc_assert (loc_insn
);
2827 emit_insn_before_setloc (seq
, jump
, INSN_LOCATOR (loc_insn
));
2831 delete_basic_block (else_bb
);
2835 remove_edge (find_edge (test_bb
, join_bb
));
2837 remove_edge (find_edge (then_bb
, join_bb
));
2838 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2839 delete_basic_block (then_bb
);
2842 if (can_merge_blocks_p (test_bb
, join_bb
))
2844 merge_blocks (test_bb
, join_bb
);
2848 num_updated_if_blocks
++;
2850 VEC_free (int, heap
, then_regs
);
2851 VEC_free (int, heap
, else_regs
);
2856 /* Determine if a given basic block heads a simple IF-THEN-JOIN or an
2857 IF-THEN-ELSE-JOIN block.
2859 If so, we'll try to convert the insns to not require the branch,
2860 using only transformations that do not require conditional execution.
2862 Return TRUE if we were successful at converting the block. */
2865 noce_find_if_block (basic_block test_bb
, edge then_edge
, edge else_edge
,
2868 basic_block then_bb
, else_bb
, join_bb
;
2869 bool then_else_reversed
= false;
2872 struct noce_if_info if_info
;
2874 /* We only ever should get here before reload. */
2875 gcc_assert (!reload_completed
);
2877 /* Recognize an IF-THEN-ELSE-JOIN block. */
2878 if (single_pred_p (then_edge
->dest
)
2879 && single_succ_p (then_edge
->dest
)
2880 && single_pred_p (else_edge
->dest
)
2881 && single_succ_p (else_edge
->dest
)
2882 && single_succ (then_edge
->dest
) == single_succ (else_edge
->dest
))
2884 then_bb
= then_edge
->dest
;
2885 else_bb
= else_edge
->dest
;
2886 join_bb
= single_succ (then_bb
);
2888 /* Recognize an IF-THEN-JOIN block. */
2889 else if (single_pred_p (then_edge
->dest
)
2890 && single_succ_p (then_edge
->dest
)
2891 && single_succ (then_edge
->dest
) == else_edge
->dest
)
2893 then_bb
= then_edge
->dest
;
2894 else_bb
= NULL_BLOCK
;
2895 join_bb
= else_edge
->dest
;
2897 /* Recognize an IF-ELSE-JOIN block. We can have those because the order
2898 of basic blocks in cfglayout mode does not matter, so the fallthrough
2899 edge can go to any basic block (and not just to bb->next_bb, like in
2901 else if (single_pred_p (else_edge
->dest
)
2902 && single_succ_p (else_edge
->dest
)
2903 && single_succ (else_edge
->dest
) == then_edge
->dest
)
2905 /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
2906 To make this work, we have to invert the THEN and ELSE blocks
2907 and reverse the jump condition. */
2908 then_bb
= else_edge
->dest
;
2909 else_bb
= NULL_BLOCK
;
2910 join_bb
= single_succ (then_bb
);
2911 then_else_reversed
= true;
2914 /* Not a form we can handle. */
2917 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
2918 if (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
2921 && single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
2924 num_possible_if_blocks
++;
2929 "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
2930 (else_bb
) ? "-ELSE" : "",
2931 pass
, test_bb
->index
, then_bb
->index
);
2934 fprintf (dump_file
, ", else %d", else_bb
->index
);
2936 fprintf (dump_file
, ", join %d\n", join_bb
->index
);
2939 /* If the conditional jump is more than just a conditional
2940 jump, then we can not do if-conversion on this block. */
2941 jump
= BB_END (test_bb
);
2942 if (! onlyjump_p (jump
))
2945 /* If this is not a standard conditional jump, we can't parse it. */
2946 cond
= noce_get_condition (jump
, &cond_earliest
, then_else_reversed
);
2950 /* We must be comparing objects whose modes imply the size. */
2951 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
2954 /* Initialize an IF_INFO struct to pass around. */
2955 memset (&if_info
, 0, sizeof if_info
);
2956 if_info
.test_bb
= test_bb
;
2957 if_info
.then_bb
= then_bb
;
2958 if_info
.else_bb
= else_bb
;
2959 if_info
.join_bb
= join_bb
;
2960 if_info
.cond
= cond
;
2961 if_info
.cond_earliest
= cond_earliest
;
2962 if_info
.jump
= jump
;
2963 if_info
.then_else_reversed
= then_else_reversed
;
2964 if_info
.branch_cost
= BRANCH_COST (optimize_bb_for_speed_p (test_bb
),
2965 predictable_edge_p (then_edge
));
2967 /* Do the real work. */
2969 if (noce_process_if_block (&if_info
))
2972 if (HAVE_conditional_move
2973 && cond_move_process_if_block (&if_info
))
2980 /* Merge the blocks and mark for local life update. */
2983 merge_if_block (struct ce_if_block
* ce_info
)
2985 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
2986 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
2987 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
2988 basic_block join_bb
= ce_info
->join_bb
; /* join block */
2989 basic_block combo_bb
;
2991 /* All block merging is done into the lower block numbers. */
2994 df_set_bb_dirty (test_bb
);
2996 /* Merge any basic blocks to handle && and || subtests. Each of
2997 the blocks are on the fallthru path from the predecessor block. */
2998 if (ce_info
->num_multiple_test_blocks
> 0)
3000 basic_block bb
= test_bb
;
3001 basic_block last_test_bb
= ce_info
->last_test_bb
;
3002 basic_block fallthru
= block_fallthru (bb
);
3007 fallthru
= block_fallthru (bb
);
3008 merge_blocks (combo_bb
, bb
);
3011 while (bb
!= last_test_bb
);
3014 /* Merge TEST block into THEN block. Normally the THEN block won't have a
3015 label, but it might if there were || tests. That label's count should be
3016 zero, and it normally should be removed. */
3020 merge_blocks (combo_bb
, then_bb
);
3024 /* The ELSE block, if it existed, had a label. That label count
3025 will almost always be zero, but odd things can happen when labels
3026 get their addresses taken. */
3029 merge_blocks (combo_bb
, else_bb
);
3033 /* If there was no join block reported, that means it was not adjacent
3034 to the others, and so we cannot merge them. */
3038 rtx last
= BB_END (combo_bb
);
3040 /* The outgoing edge for the current COMBO block should already
3041 be correct. Verify this. */
3042 if (EDGE_COUNT (combo_bb
->succs
) == 0)
3043 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
3044 || (NONJUMP_INSN_P (last
)
3045 && GET_CODE (PATTERN (last
)) == TRAP_IF
3046 && (TRAP_CONDITION (PATTERN (last
))
3047 == const_true_rtx
)));
3050 /* There should still be something at the end of the THEN or ELSE
3051 blocks taking us to our final destination. */
3052 gcc_assert (JUMP_P (last
)
3053 || (EDGE_SUCC (combo_bb
, 0)->dest
== EXIT_BLOCK_PTR
3055 && SIBLING_CALL_P (last
))
3056 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
3057 && can_throw_internal (last
)));
3060 /* The JOIN block may have had quite a number of other predecessors too.
3061 Since we've already merged the TEST, THEN and ELSE blocks, we should
3062 have only one remaining edge from our if-then-else diamond. If there
3063 is more than one remaining edge, it must come from elsewhere. There
3064 may be zero incoming edges if the THEN block didn't actually join
3065 back up (as with a call to a non-return function). */
3066 else if (EDGE_COUNT (join_bb
->preds
) < 2
3067 && join_bb
!= EXIT_BLOCK_PTR
)
3069 /* We can merge the JOIN cleanly and update the dataflow try
3070 again on this pass.*/
3071 merge_blocks (combo_bb
, join_bb
);
3076 /* We cannot merge the JOIN. */
3078 /* The outgoing edge for the current COMBO block should already
3079 be correct. Verify this. */
3080 gcc_assert (single_succ_p (combo_bb
)
3081 && single_succ (combo_bb
) == join_bb
);
3083 /* Remove the jump and cruft from the end of the COMBO block. */
3084 if (join_bb
!= EXIT_BLOCK_PTR
)
3085 tidy_fallthru_edge (single_succ_edge (combo_bb
));
3088 num_updated_if_blocks
++;
3091 /* Find a block ending in a simple IF condition and try to transform it
3092 in some way. When converting a multi-block condition, put the new code
3093 in the first such block and delete the rest. Return a pointer to this
3094 first block if some transformation was done. Return NULL otherwise. */
3097 find_if_header (basic_block test_bb
, int pass
)
3099 ce_if_block_t ce_info
;
3103 /* The kind of block we're looking for has exactly two successors. */
3104 if (EDGE_COUNT (test_bb
->succs
) != 2)
3107 then_edge
= EDGE_SUCC (test_bb
, 0);
3108 else_edge
= EDGE_SUCC (test_bb
, 1);
3110 if (df_get_bb_dirty (then_edge
->dest
))
3112 if (df_get_bb_dirty (else_edge
->dest
))
3115 /* Neither edge should be abnormal. */
3116 if ((then_edge
->flags
& EDGE_COMPLEX
)
3117 || (else_edge
->flags
& EDGE_COMPLEX
))
3120 /* Nor exit the loop. */
3121 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
3122 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
3125 /* The THEN edge is canonically the one that falls through. */
3126 if (then_edge
->flags
& EDGE_FALLTHRU
)
3128 else if (else_edge
->flags
& EDGE_FALLTHRU
)
3131 else_edge
= then_edge
;
3135 /* Otherwise this must be a multiway branch of some sort. */
3138 memset (&ce_info
, 0, sizeof (ce_info
));
3139 ce_info
.test_bb
= test_bb
;
3140 ce_info
.then_bb
= then_edge
->dest
;
3141 ce_info
.else_bb
= else_edge
->dest
;
3142 ce_info
.pass
= pass
;
3144 #ifdef IFCVT_INIT_EXTRA_FIELDS
3145 IFCVT_INIT_EXTRA_FIELDS (&ce_info
);
3148 if (!reload_completed
3149 && noce_find_if_block (test_bb
, then_edge
, else_edge
, pass
))
3152 if (reload_completed
3153 && targetm
.have_conditional_execution ()
3154 && cond_exec_find_if_block (&ce_info
))
3158 && optab_handler (ctrap_optab
, word_mode
) != CODE_FOR_nothing
3159 && find_cond_trap (test_bb
, then_edge
, else_edge
))
3162 if (dom_info_state (CDI_POST_DOMINATORS
) >= DOM_NO_FAST_QUERY
3163 && (reload_completed
|| !targetm
.have_conditional_execution ()))
3165 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
3167 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
3175 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
3176 /* Set this so we continue looking. */
3177 cond_exec_changed_p
= TRUE
;
3178 return ce_info
.test_bb
;
3181 /* Return true if a block has two edges, one of which falls through to the next
3182 block, and the other jumps to a specific block, so that we can tell if the
3183 block is part of an && test or an || test. Returns either -1 or the number
3184 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
3187 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
3190 int fallthru_p
= FALSE
;
3197 if (!cur_bb
|| !target_bb
)
3200 /* If no edges, obviously it doesn't jump or fallthru. */
3201 if (EDGE_COUNT (cur_bb
->succs
) == 0)
3204 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
3206 if (cur_edge
->flags
& EDGE_COMPLEX
)
3207 /* Anything complex isn't what we want. */
3210 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
3213 else if (cur_edge
->dest
== target_bb
)
3220 if ((jump_p
& fallthru_p
) == 0)
3223 /* Don't allow calls in the block, since this is used to group && and ||
3224 together for conditional execution support. ??? we should support
3225 conditional execution support across calls for IA-64 some day, but
3226 for now it makes the code simpler. */
3227 end
= BB_END (cur_bb
);
3228 insn
= BB_HEAD (cur_bb
);
3230 while (insn
!= NULL_RTX
)
3237 && !DEBUG_INSN_P (insn
)
3238 && GET_CODE (PATTERN (insn
)) != USE
3239 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
3245 insn
= NEXT_INSN (insn
);
3251 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3252 block. If so, we'll try to convert the insns to not require the branch.
3253 Return TRUE if we were successful at converting the block. */
3256 cond_exec_find_if_block (struct ce_if_block
* ce_info
)
3258 basic_block test_bb
= ce_info
->test_bb
;
3259 basic_block then_bb
= ce_info
->then_bb
;
3260 basic_block else_bb
= ce_info
->else_bb
;
3261 basic_block join_bb
= NULL_BLOCK
;
3266 ce_info
->last_test_bb
= test_bb
;
3268 /* We only ever should get here after reload,
3269 and if we have conditional execution. */
3270 gcc_assert (reload_completed
&& targetm
.have_conditional_execution ());
3272 /* Discover if any fall through predecessors of the current test basic block
3273 were && tests (which jump to the else block) or || tests (which jump to
3275 if (single_pred_p (test_bb
)
3276 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
3278 basic_block bb
= single_pred (test_bb
);
3279 basic_block target_bb
;
3280 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
3283 /* Determine if the preceding block is an && or || block. */
3284 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
3286 ce_info
->and_and_p
= TRUE
;
3287 target_bb
= else_bb
;
3289 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
3291 ce_info
->and_and_p
= FALSE
;
3292 target_bb
= then_bb
;
3295 target_bb
= NULL_BLOCK
;
3297 if (target_bb
&& n_insns
<= max_insns
)
3299 int total_insns
= 0;
3302 ce_info
->last_test_bb
= test_bb
;
3304 /* Found at least one && or || block, look for more. */
3307 ce_info
->test_bb
= test_bb
= bb
;
3308 total_insns
+= n_insns
;
3311 if (!single_pred_p (bb
))
3314 bb
= single_pred (bb
);
3315 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
3317 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
3319 ce_info
->num_multiple_test_blocks
= blocks
;
3320 ce_info
->num_multiple_test_insns
= total_insns
;
3322 if (ce_info
->and_and_p
)
3323 ce_info
->num_and_and_blocks
= blocks
;
3325 ce_info
->num_or_or_blocks
= blocks
;
3329 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3330 other than any || blocks which jump to the THEN block. */
3331 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
3334 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3335 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
3337 if (cur_edge
->flags
& EDGE_COMPLEX
)
3341 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
3343 if (cur_edge
->flags
& EDGE_COMPLEX
)
3347 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3348 if (EDGE_COUNT (then_bb
->succs
) > 0
3349 && (!single_succ_p (then_bb
)
3350 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3351 || (epilogue_completed
3352 && tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
3355 /* If the THEN block has no successors, conditional execution can still
3356 make a conditional call. Don't do this unless the ELSE block has
3357 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3358 Check for the last insn of the THEN block being an indirect jump, which
3359 is listed as not having any successors, but confuses the rest of the CE
3360 code processing. ??? we should fix this in the future. */
3361 if (EDGE_COUNT (then_bb
->succs
) == 0)
3363 if (single_pred_p (else_bb
))
3365 rtx last_insn
= BB_END (then_bb
);
3368 && NOTE_P (last_insn
)
3369 && last_insn
!= BB_HEAD (then_bb
))
3370 last_insn
= PREV_INSN (last_insn
);
3373 && JUMP_P (last_insn
)
3374 && ! simplejump_p (last_insn
))
3378 else_bb
= NULL_BLOCK
;
3384 /* If the THEN block's successor is the other edge out of the TEST block,
3385 then we have an IF-THEN combo without an ELSE. */
3386 else if (single_succ (then_bb
) == else_bb
)
3389 else_bb
= NULL_BLOCK
;
3392 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3393 has exactly one predecessor and one successor, and the outgoing edge
3394 is not complex, then we have an IF-THEN-ELSE combo. */
3395 else if (single_succ_p (else_bb
)
3396 && single_succ (then_bb
) == single_succ (else_bb
)
3397 && single_pred_p (else_bb
)
3398 && !(single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3399 && !(epilogue_completed
3400 && tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
3401 join_bb
= single_succ (else_bb
);
3403 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3407 num_possible_if_blocks
++;
3412 "\nIF-THEN%s block found, pass %d, start block %d "
3413 "[insn %d], then %d [%d]",
3414 (else_bb
) ? "-ELSE" : "",
3417 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
3419 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
3422 fprintf (dump_file
, ", else %d [%d]",
3424 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
3426 fprintf (dump_file
, ", join %d [%d]",
3428 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
3430 if (ce_info
->num_multiple_test_blocks
> 0)
3431 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
3432 ce_info
->num_multiple_test_blocks
,
3433 (ce_info
->and_and_p
) ? "&&" : "||",
3434 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
3435 ce_info
->last_test_bb
->index
,
3436 ((BB_HEAD (ce_info
->last_test_bb
))
3437 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
3440 fputc ('\n', dump_file
);
3443 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3444 first condition for free, since we've already asserted that there's a
3445 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3446 we checked the FALLTHRU flag, those are already adjacent to the last IF
3448 /* ??? As an enhancement, move the ELSE block. Have to deal with
3449 BLOCK notes, if by no other means than backing out the merge if they
3450 exist. Sticky enough I don't want to think about it now. */
3452 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
3454 if ((next
= next
->next_bb
) != join_bb
&& join_bb
!= EXIT_BLOCK_PTR
)
3462 /* Do the real work. */
3464 ce_info
->else_bb
= else_bb
;
3465 ce_info
->join_bb
= join_bb
;
3467 /* If we have && and || tests, try to first handle combining the && and ||
3468 tests into the conditional code, and if that fails, go back and handle
3469 it without the && and ||, which at present handles the && case if there
3470 was no ELSE block. */
3471 if (cond_exec_process_if_block (ce_info
, TRUE
))
3474 if (ce_info
->num_multiple_test_blocks
)
3478 if (cond_exec_process_if_block (ce_info
, FALSE
))
3485 /* Convert a branch over a trap, or a branch
3486 to a trap, into a conditional trap. */
3489 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
3491 basic_block then_bb
= then_edge
->dest
;
3492 basic_block else_bb
= else_edge
->dest
;
3493 basic_block other_bb
, trap_bb
;
3494 rtx trap
, jump
, cond
, cond_earliest
, seq
;
3497 /* Locate the block with the trap instruction. */
3498 /* ??? While we look for no successors, we really ought to allow
3499 EH successors. Need to fix merge_if_block for that to work. */
3500 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
3501 trap_bb
= then_bb
, other_bb
= else_bb
;
3502 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
3503 trap_bb
= else_bb
, other_bb
= then_bb
;
3509 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
3510 test_bb
->index
, trap_bb
->index
);
3513 /* If this is not a standard conditional jump, we can't parse it. */
3514 jump
= BB_END (test_bb
);
3515 cond
= noce_get_condition (jump
, &cond_earliest
, false);
3519 /* If the conditional jump is more than just a conditional jump, then
3520 we can not do if-conversion on this block. */
3521 if (! onlyjump_p (jump
))
3524 /* We must be comparing objects whose modes imply the size. */
3525 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3528 /* Reverse the comparison code, if necessary. */
3529 code
= GET_CODE (cond
);
3530 if (then_bb
== trap_bb
)
3532 code
= reversed_comparison_code (cond
, jump
);
3533 if (code
== UNKNOWN
)
3537 /* Attempt to generate the conditional trap. */
3538 seq
= gen_cond_trap (code
, copy_rtx (XEXP (cond
, 0)),
3539 copy_rtx (XEXP (cond
, 1)),
3540 TRAP_CODE (PATTERN (trap
)));
3544 /* Emit the new insns before cond_earliest. */
3545 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATOR (trap
));
3547 /* Delete the trap block if possible. */
3548 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
3549 df_set_bb_dirty (test_bb
);
3550 df_set_bb_dirty (then_bb
);
3551 df_set_bb_dirty (else_bb
);
3553 if (EDGE_COUNT (trap_bb
->preds
) == 0)
3555 delete_basic_block (trap_bb
);
3559 /* Wire together the blocks again. */
3560 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
3561 single_succ_edge (test_bb
)->flags
|= EDGE_FALLTHRU
;
3566 lab
= JUMP_LABEL (jump
);
3567 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
3568 LABEL_NUSES (lab
) += 1;
3569 JUMP_LABEL (newjump
) = lab
;
3570 emit_barrier_after (newjump
);
3574 if (can_merge_blocks_p (test_bb
, other_bb
))
3576 merge_blocks (test_bb
, other_bb
);
3580 num_updated_if_blocks
++;
3584 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3588 block_has_only_trap (basic_block bb
)
3592 /* We're not the exit block. */
3593 if (bb
== EXIT_BLOCK_PTR
)
3596 /* The block must have no successors. */
3597 if (EDGE_COUNT (bb
->succs
) > 0)
3600 /* The only instruction in the THEN block must be the trap. */
3601 trap
= first_active_insn (bb
);
3602 if (! (trap
== BB_END (bb
)
3603 && GET_CODE (PATTERN (trap
)) == TRAP_IF
3604 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
3610 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3611 transformable, but not necessarily the other. There need be no
3614 Return TRUE if we were successful at converting the block.
3616 Cases we'd like to look at:
3619 if (test) goto over; // x not live
3627 if (! test) goto label;
3630 if (test) goto E; // x not live
3644 (3) // This one's really only interesting for targets that can do
3645 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3646 // it results in multiple branches on a cache line, which often
3647 // does not sit well with predictors.
3649 if (test1) goto E; // predicted not taken
3665 (A) Don't do (2) if the branch is predicted against the block we're
3666 eliminating. Do it anyway if we can eliminate a branch; this requires
3667 that the sole successor of the eliminated block postdominate the other
3670 (B) With CE, on (3) we can steal from both sides of the if, creating
3679 Again, this is most useful if J postdominates.
3681 (C) CE substitutes for helpful life information.
3683 (D) These heuristics need a lot of work. */
3685 /* Tests for case 1 above. */
3688 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3690 basic_block then_bb
= then_edge
->dest
;
3691 basic_block else_bb
= else_edge
->dest
;
3695 /* If we are partitioning hot/cold basic blocks, we don't want to
3696 mess up unconditional or indirect jumps that cross between hot
3699 Basic block partitioning may result in some jumps that appear to
3700 be optimizable (or blocks that appear to be mergeable), but which really
3701 must be left untouched (they are required to make it safely across
3702 partition boundaries). See the comments at the top of
3703 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3705 if ((BB_END (then_bb
)
3706 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3707 || (BB_END (test_bb
)
3708 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3709 || (BB_END (else_bb
)
3710 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3714 /* THEN has one successor. */
3715 if (!single_succ_p (then_bb
))
3718 /* THEN does not fall through, but is not strange either. */
3719 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
3722 /* THEN has one predecessor. */
3723 if (!single_pred_p (then_bb
))
3726 /* THEN must do something. */
3727 if (forwarder_block_p (then_bb
))
3730 num_possible_if_blocks
++;
3733 "\nIF-CASE-1 found, start %d, then %d\n",
3734 test_bb
->index
, then_bb
->index
);
3736 /* THEN is small. */
3737 if (! cheap_bb_rtx_cost_p (then_bb
,
3738 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge
->src
),
3739 predictable_edge_p (then_edge
)))))
3742 /* Registers set are dead, or are predicable. */
3743 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
3744 single_succ (then_bb
), 1))
3747 /* Conversion went ok, including moving the insns and fixing up the
3748 jump. Adjust the CFG to match. */
3750 /* We can avoid creating a new basic block if then_bb is immediately
3751 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3754 if (then_bb
->next_bb
== else_bb
3755 && then_bb
->prev_bb
== test_bb
3756 && else_bb
!= EXIT_BLOCK_PTR
)
3758 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
3762 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
3765 df_set_bb_dirty (test_bb
);
3766 df_set_bb_dirty (else_bb
);
3768 then_bb_index
= then_bb
->index
;
3769 delete_basic_block (then_bb
);
3771 /* Make rest of code believe that the newly created block is the THEN_BB
3772 block we removed. */
3775 df_bb_replace (then_bb_index
, new_bb
);
3776 /* Since the fallthru edge was redirected from test_bb to new_bb,
3777 we need to ensure that new_bb is in the same partition as
3778 test bb (you can not fall through across section boundaries). */
3779 BB_COPY_PARTITION (new_bb
, test_bb
);
3783 num_updated_if_blocks
++;
3788 /* Test for case 2 above. */
3791 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3793 basic_block then_bb
= then_edge
->dest
;
3794 basic_block else_bb
= else_edge
->dest
;
3798 /* If we are partitioning hot/cold basic blocks, we don't want to
3799 mess up unconditional or indirect jumps that cross between hot
3802 Basic block partitioning may result in some jumps that appear to
3803 be optimizable (or blocks that appear to be mergeable), but which really
3804 must be left untouched (they are required to make it safely across
3805 partition boundaries). See the comments at the top of
3806 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3808 if ((BB_END (then_bb
)
3809 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3810 || (BB_END (test_bb
)
3811 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3812 || (BB_END (else_bb
)
3813 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3817 /* ELSE has one successor. */
3818 if (!single_succ_p (else_bb
))
3821 else_succ
= single_succ_edge (else_bb
);
3823 /* ELSE outgoing edge is not complex. */
3824 if (else_succ
->flags
& EDGE_COMPLEX
)
3827 /* ELSE has one predecessor. */
3828 if (!single_pred_p (else_bb
))
3831 /* THEN is not EXIT. */
3832 if (then_bb
->index
< NUM_FIXED_BLOCKS
)
3835 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
3836 note
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
3837 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
3839 else if (else_succ
->dest
->index
< NUM_FIXED_BLOCKS
3840 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
3846 num_possible_if_blocks
++;
3849 "\nIF-CASE-2 found, start %d, else %d\n",
3850 test_bb
->index
, else_bb
->index
);
3852 /* ELSE is small. */
3853 if (! cheap_bb_rtx_cost_p (else_bb
,
3854 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge
->src
),
3855 predictable_edge_p (else_edge
)))))
3858 /* Registers set are dead, or are predicable. */
3859 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
3862 /* Conversion went ok, including moving the insns and fixing up the
3863 jump. Adjust the CFG to match. */
3865 df_set_bb_dirty (test_bb
);
3866 df_set_bb_dirty (then_bb
);
3867 delete_basic_block (else_bb
);
3870 num_updated_if_blocks
++;
3872 /* ??? We may now fallthru from one of THEN's successors into a join
3873 block. Rerun cleanup_cfg? Examine things manually? Wait? */
3878 /* A subroutine of dead_or_predicable called through for_each_rtx.
3879 Return 1 if a memory is found. */
3882 find_memory (rtx
*px
, void *data ATTRIBUTE_UNUSED
)
3887 /* Used by the code above to perform the actual rtl transformations.
3888 Return TRUE if successful.
3890 TEST_BB is the block containing the conditional branch. MERGE_BB
3891 is the block containing the code to manipulate. NEW_DEST is the
3892 label TEST_BB should be branching to after the conversion.
3893 REVERSEP is true if the sense of the branch should be reversed. */
3896 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
3897 basic_block other_bb
, basic_block new_dest
, int reversep
)
3899 rtx head
, end
, jump
, earliest
= NULL_RTX
, old_dest
, new_label
= NULL_RTX
;
3900 /* Number of pending changes. */
3901 int n_validated_changes
= 0;
3903 jump
= BB_END (test_bb
);
3905 /* Find the extent of the real code in the merge block. */
3906 head
= BB_HEAD (merge_bb
);
3907 end
= BB_END (merge_bb
);
3909 while (DEBUG_INSN_P (end
) && end
!= head
)
3910 end
= PREV_INSN (end
);
3912 /* If merge_bb ends with a tablejump, predicating/moving insn's
3913 into test_bb and then deleting merge_bb will result in the jumptable
3914 that follows merge_bb being removed along with merge_bb and then we
3915 get an unresolved reference to the jumptable. */
3916 if (tablejump_p (end
, NULL
, NULL
))
3920 head
= NEXT_INSN (head
);
3921 while (DEBUG_INSN_P (head
) && head
!= end
)
3922 head
= NEXT_INSN (head
);
3927 head
= end
= NULL_RTX
;
3930 head
= NEXT_INSN (head
);
3931 while (DEBUG_INSN_P (head
) && head
!= end
)
3932 head
= NEXT_INSN (head
);
3939 head
= end
= NULL_RTX
;
3942 end
= PREV_INSN (end
);
3943 while (DEBUG_INSN_P (end
) && end
!= head
)
3944 end
= PREV_INSN (end
);
3947 /* Disable handling dead code by conditional execution if the machine needs
3948 to do anything funny with the tests, etc. */
3949 #ifndef IFCVT_MODIFY_TESTS
3950 if (targetm
.have_conditional_execution ())
3952 /* In the conditional execution case, we have things easy. We know
3953 the condition is reversible. We don't have to check life info
3954 because we're going to conditionally execute the code anyway.
3955 All that's left is making sure the insns involved can actually
3960 cond
= cond_exec_get_condition (jump
);
3964 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
3966 prob_val
= XEXP (prob_val
, 0);
3970 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
3973 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
3976 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
3979 if (cond_exec_process_insns (NULL
, head
, end
, cond
, prob_val
, 0)
3980 && verify_changes (0))
3981 n_validated_changes
= num_validated_changes ();
3988 /* Try the NCE path if the CE path did not result in any changes. */
3989 if (n_validated_changes
== 0)
3991 /* In the non-conditional execution case, we have to verify that there
3992 are no trapping operations, no calls, no references to memory, and
3993 that any registers modified are dead at the branch site. */
3995 rtx insn
, cond
, prev
;
3996 bitmap merge_set
, merge_set_noclobber
, test_live
, test_set
;
3997 unsigned i
, fail
= 0;
4000 /* Check for no calls or trapping operations. */
4001 for (insn
= head
; ; insn
= NEXT_INSN (insn
))
4005 if (NONDEBUG_INSN_P (insn
))
4007 if (may_trap_p (PATTERN (insn
)))
4010 /* ??? Even non-trapping memories such as stack frame
4011 references must be avoided. For stores, we collect
4012 no lifetime info; for reads, we'd have to assert
4013 true_dependence false against every store in the
4015 if (for_each_rtx (&PATTERN (insn
), find_memory
, NULL
))
4022 if (! any_condjump_p (jump
))
4025 /* Find the extent of the conditional. */
4026 cond
= noce_get_condition (jump
, &earliest
, false);
4031 MERGE_SET = set of registers set in MERGE_BB
4032 MERGE_SET_NOCLOBBER = like MERGE_SET, but only includes registers
4033 that are really set, not just clobbered.
4034 TEST_LIVE = set of registers live at EARLIEST
4035 TEST_SET = set of registers set between EARLIEST and the
4036 end of the block. */
4038 merge_set
= BITMAP_ALLOC (®_obstack
);
4039 merge_set_noclobber
= BITMAP_ALLOC (®_obstack
);
4040 test_live
= BITMAP_ALLOC (®_obstack
);
4041 test_set
= BITMAP_ALLOC (®_obstack
);
4043 /* ??? bb->local_set is only valid during calculate_global_regs_live,
4044 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
4045 since we've already asserted that MERGE_BB is small. */
4046 /* If we allocated new pseudos (e.g. in the conditional move
4047 expander called from noce_emit_cmove), we must resize the
4049 if (max_regno
< max_reg_num ())
4050 max_regno
= max_reg_num ();
4052 FOR_BB_INSNS (merge_bb
, insn
)
4054 if (NONDEBUG_INSN_P (insn
))
4056 df_simulate_find_defs (insn
, merge_set
);
4057 df_simulate_find_noclobber_defs (insn
, merge_set_noclobber
);
4061 /* For small register class machines, don't lengthen lifetimes of
4062 hard registers before reload. */
4063 if (! reload_completed
4064 && targetm
.small_register_classes_for_mode_p (VOIDmode
))
4066 EXECUTE_IF_SET_IN_BITMAP (merge_set_noclobber
, 0, i
, bi
)
4068 if (i
< FIRST_PSEUDO_REGISTER
4070 && ! global_regs
[i
])
4075 /* For TEST, we're interested in a range of insns, not a whole block.
4076 Moreover, we're interested in the insns live from OTHER_BB. */
4078 /* The loop below takes the set of live registers
4079 after JUMP, and calculates the live set before EARLIEST. */
4080 bitmap_copy (test_live
, df_get_live_in (other_bb
));
4081 df_simulate_initialize_backwards (test_bb
, test_live
);
4082 for (insn
= jump
; ; insn
= prev
)
4086 df_simulate_find_defs (insn
, test_set
);
4087 df_simulate_one_insn_backwards (test_bb
, insn
, test_live
);
4089 prev
= PREV_INSN (insn
);
4090 if (insn
== earliest
)
4094 /* We can perform the transformation if
4095 MERGE_SET_NOCLOBBER & TEST_SET
4097 MERGE_SET & TEST_LIVE)
4099 TEST_SET & DF_LIVE_IN (merge_bb)
4102 if (bitmap_intersect_p (test_set
, merge_set_noclobber
)
4103 || bitmap_intersect_p (test_live
, merge_set
)
4104 || bitmap_intersect_p (test_set
, df_get_live_in (merge_bb
)))
4107 BITMAP_FREE (merge_set_noclobber
);
4108 BITMAP_FREE (merge_set
);
4109 BITMAP_FREE (test_live
);
4110 BITMAP_FREE (test_set
);
4117 /* We don't want to use normal invert_jump or redirect_jump because
4118 we don't want to delete_insn called. Also, we want to do our own
4119 change group management. */
4121 old_dest
= JUMP_LABEL (jump
);
4122 if (other_bb
!= new_dest
)
4124 new_label
= block_label (new_dest
);
4126 ? ! invert_jump_1 (jump
, new_label
)
4127 : ! redirect_jump_1 (jump
, new_label
))
4131 if (verify_changes (n_validated_changes
))
4132 confirm_change_group ();
4136 if (other_bb
!= new_dest
)
4138 redirect_jump_2 (jump
, old_dest
, new_label
, 0, reversep
);
4140 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
4143 gcov_type count
, probability
;
4144 count
= BRANCH_EDGE (test_bb
)->count
;
4145 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
4146 FALLTHRU_EDGE (test_bb
)->count
= count
;
4147 probability
= BRANCH_EDGE (test_bb
)->probability
;
4148 BRANCH_EDGE (test_bb
)->probability
4149 = FALLTHRU_EDGE (test_bb
)->probability
;
4150 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
4151 update_br_prob_note (test_bb
);
4155 /* Move the insns out of MERGE_BB to before the branch. */
4160 if (end
== BB_END (merge_bb
))
4161 BB_END (merge_bb
) = PREV_INSN (head
);
4163 /* PR 21767: When moving insns above a conditional branch, REG_EQUAL
4164 notes might become invalid. */
4170 if (! INSN_P (insn
))
4172 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
4175 set
= single_set (insn
);
4176 if (!set
|| !function_invariant_p (SET_SRC (set
))
4177 || !function_invariant_p (XEXP (note
, 0)))
4178 remove_note (insn
, note
);
4179 } while (insn
!= end
&& (insn
= NEXT_INSN (insn
)));
4181 reorder_insns (head
, end
, PREV_INSN (earliest
));
4184 /* Remove the jump and edge if we can. */
4185 if (other_bb
== new_dest
)
4188 remove_edge (BRANCH_EDGE (test_bb
));
4189 /* ??? Can't merge blocks here, as then_bb is still in use.
4190 At minimum, the merge will get done just before bb-reorder. */
4200 /* Main entry point for all if-conversion. */
4210 df_live_add_problem ();
4211 df_live_set_all_dirty ();
4214 num_possible_if_blocks
= 0;
4215 num_updated_if_blocks
= 0;
4216 num_true_changes
= 0;
4218 loop_optimizer_init (AVOID_CFG_MODIFICATIONS
);
4219 mark_loop_exit_edges ();
4220 loop_optimizer_finalize ();
4221 free_dominance_info (CDI_DOMINATORS
);
4223 /* Compute postdominators. */
4224 calculate_dominance_info (CDI_POST_DOMINATORS
);
4226 df_set_flags (DF_LR_RUN_DCE
);
4228 /* Go through each of the basic blocks looking for things to convert. If we
4229 have conditional execution, we make multiple passes to allow us to handle
4230 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
4235 /* Only need to do dce on the first pass. */
4236 df_clear_flags (DF_LR_RUN_DCE
);
4237 cond_exec_changed_p
= FALSE
;
4240 #ifdef IFCVT_MULTIPLE_DUMPS
4241 if (dump_file
&& pass
> 1)
4242 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
4248 while (!df_get_bb_dirty (bb
)
4249 && (new_bb
= find_if_header (bb
, pass
)) != NULL
)
4253 #ifdef IFCVT_MULTIPLE_DUMPS
4254 if (dump_file
&& cond_exec_changed_p
)
4256 if (dump_flags
& TDF_SLIM
)
4257 print_rtl_slim_with_bb (dump_file
, get_insns (), dump_flags
);
4259 print_rtl_with_bb (dump_file
, get_insns ());
4263 while (cond_exec_changed_p
);
4265 #ifdef IFCVT_MULTIPLE_DUMPS
4267 fprintf (dump_file
, "\n\n========== no more changes\n");
4270 free_dominance_info (CDI_POST_DOMINATORS
);
4275 clear_aux_for_blocks ();
4277 /* If we allocated new pseudos, we must resize the array for sched1. */
4278 if (max_regno
< max_reg_num ())
4279 max_regno
= max_reg_num ();
4281 /* Write the final stats. */
4282 if (dump_file
&& num_possible_if_blocks
> 0)
4285 "\n%d possible IF blocks searched.\n",
4286 num_possible_if_blocks
);
4288 "%d IF blocks converted.\n",
4289 num_updated_if_blocks
);
4291 "%d true changes made.\n\n\n",
4296 df_remove_problem (df_live
);
4298 #ifdef ENABLE_CHECKING
4299 verify_flow_info ();
4304 gate_handle_if_conversion (void)
4306 return (optimize
> 0)
4307 && dbg_cnt (if_conversion
);
4310 /* If-conversion and CFG cleanup. */
4312 rest_of_handle_if_conversion (void)
4314 if (flag_if_conversion
)
4317 dump_flow_info (dump_file
, dump_flags
);
4318 cleanup_cfg (CLEANUP_EXPENSIVE
);
4326 struct rtl_opt_pass pass_rtl_ifcvt
=
4331 gate_handle_if_conversion
, /* gate */
4332 rest_of_handle_if_conversion
, /* execute */
4335 0, /* static_pass_number */
4336 TV_IFCVT
, /* tv_id */
4337 0, /* properties_required */
4338 0, /* properties_provided */
4339 0, /* properties_destroyed */
4340 0, /* todo_flags_start */
4341 TODO_df_finish
| TODO_verify_rtl_sharing
|
4342 TODO_dump_func
/* todo_flags_finish */
4347 gate_handle_if_after_combine (void)
4349 return optimize
> 0 && flag_if_conversion
4350 && dbg_cnt (if_after_combine
);
4354 /* Rerun if-conversion, as combine may have simplified things enough
4355 to now meet sequence length restrictions. */
4357 rest_of_handle_if_after_combine (void)
4363 struct rtl_opt_pass pass_if_after_combine
=
4368 gate_handle_if_after_combine
, /* gate */
4369 rest_of_handle_if_after_combine
, /* execute */
4372 0, /* static_pass_number */
4373 TV_IFCVT
, /* tv_id */
4374 0, /* properties_required */
4375 0, /* properties_provided */
4376 0, /* properties_destroyed */
4377 0, /* todo_flags_start */
4378 TODO_df_finish
| TODO_verify_rtl_sharing
|
4380 TODO_ggc_collect
/* todo_flags_finish */
4386 gate_handle_if_after_reload (void)
4388 return optimize
> 0 && flag_if_conversion2
4389 && dbg_cnt (if_after_reload
);
4393 rest_of_handle_if_after_reload (void)
4400 struct rtl_opt_pass pass_if_after_reload
=
4405 gate_handle_if_after_reload
, /* gate */
4406 rest_of_handle_if_after_reload
, /* execute */
4409 0, /* static_pass_number */
4410 TV_IFCVT2
, /* tv_id */
4411 0, /* properties_required */
4412 0, /* properties_provided */
4413 0, /* properties_destroyed */
4414 0, /* todo_flags_start */
4415 TODO_df_finish
| TODO_verify_rtl_sharing
|
4417 TODO_ggc_collect
/* todo_flags_finish */