1 /* If-conversion support.
2 Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
23 #include "coretypes.h"
30 #include "insn-config.h"
33 #include "hard-reg-set.h"
34 #include "basic-block.h"
42 #ifndef HAVE_conditional_execution
43 #define HAVE_conditional_execution 0
45 #ifndef HAVE_conditional_move
46 #define HAVE_conditional_move 0
57 #ifndef HAVE_conditional_trap
58 #define HAVE_conditional_trap 0
61 #ifndef MAX_CONDITIONAL_EXECUTE
62 #define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1)
65 #define NULL_EDGE ((struct edge_def *)NULL)
66 #define NULL_BLOCK ((struct basic_block_def *)NULL)
68 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
69 static int num_possible_if_blocks
;
71 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
73 static int num_updated_if_blocks
;
75 /* # of basic blocks that were removed. */
76 static int num_removed_blocks
;
78 /* Whether conditional execution changes were made. */
79 static int cond_exec_changed_p
;
81 /* True if life data ok at present. */
82 static bool life_data_ok
;
84 /* The post-dominator relation on the original block numbers. */
85 static dominance_info post_dominators
;
87 /* Forward references. */
88 static int count_bb_insns
PARAMS ((basic_block
));
89 static rtx first_active_insn
PARAMS ((basic_block
));
90 static rtx last_active_insn
PARAMS ((basic_block
, int));
91 static int seq_contains_jump
PARAMS ((rtx
));
92 static basic_block block_fallthru
PARAMS ((basic_block
));
93 static int cond_exec_process_insns
PARAMS ((ce_if_block_t
*,
94 rtx
, rtx
, rtx
, rtx
, int));
95 static rtx cond_exec_get_condition
PARAMS ((rtx
));
96 static int cond_exec_process_if_block
PARAMS ((ce_if_block_t
*, int));
97 static rtx noce_get_condition
PARAMS ((rtx
, rtx
*));
98 static int noce_operand_ok
PARAMS ((rtx
));
99 static int noce_process_if_block
PARAMS ((ce_if_block_t
*));
100 static int process_if_block
PARAMS ((ce_if_block_t
*));
101 static void merge_if_block
PARAMS ((ce_if_block_t
*));
102 static int find_cond_trap
PARAMS ((basic_block
, edge
, edge
));
103 static basic_block find_if_header
PARAMS ((basic_block
, int));
104 static int block_jumps_and_fallthru_p
PARAMS ((basic_block
, basic_block
));
105 static int find_if_block
PARAMS ((ce_if_block_t
*));
106 static int find_if_case_1
PARAMS ((basic_block
, edge
, edge
));
107 static int find_if_case_2
PARAMS ((basic_block
, edge
, edge
));
108 static int find_memory
PARAMS ((rtx
*, void *));
109 static int dead_or_predicable
PARAMS ((basic_block
, basic_block
,
110 basic_block
, basic_block
, int));
111 static void noce_emit_move_insn
PARAMS ((rtx
, rtx
));
112 static rtx block_has_only_trap
PARAMS ((basic_block
));
114 /* Count the number of non-jump active insns in BB. */
125 if (GET_CODE (insn
) == CALL_INSN
|| GET_CODE (insn
) == INSN
)
130 insn
= NEXT_INSN (insn
);
136 /* Return the first non-jump active insn in the basic block. */
139 first_active_insn (bb
)
144 if (GET_CODE (insn
) == CODE_LABEL
)
148 insn
= NEXT_INSN (insn
);
151 while (GET_CODE (insn
) == NOTE
)
155 insn
= NEXT_INSN (insn
);
158 if (GET_CODE (insn
) == JUMP_INSN
)
164 /* Return the last non-jump active (non-jump) insn in the basic block. */
167 last_active_insn (bb
, skip_use_p
)
174 while (GET_CODE (insn
) == NOTE
175 || GET_CODE (insn
) == JUMP_INSN
177 && GET_CODE (insn
) == INSN
178 && GET_CODE (PATTERN (insn
)) == USE
))
182 insn
= PREV_INSN (insn
);
185 if (GET_CODE (insn
) == CODE_LABEL
)
191 /* It is possible, especially when having dealt with multi-word
192 arithmetic, for the expanders to have emitted jumps. Search
193 through the sequence and return TRUE if a jump exists so that
194 we can abort the conversion. */
197 seq_contains_jump (insn
)
202 if (GET_CODE (insn
) == JUMP_INSN
)
204 insn
= NEXT_INSN (insn
);
216 e
!= NULL_EDGE
&& (e
->flags
& EDGE_FALLTHRU
) == 0;
220 return (e
) ? e
->dest
: NULL_BLOCK
;
223 /* Go through a bunch of insns, converting them to conditional
224 execution format if possible. Return TRUE if all of the non-note
225 insns were processed. */
228 cond_exec_process_insns (ce_info
, start
, end
, test
, prob_val
, mod_ok
)
229 ce_if_block_t
*ce_info ATTRIBUTE_UNUSED
; /* if block information */
230 rtx start
; /* first insn to look at */
231 rtx end
; /* last insn to look at */
232 rtx test
; /* conditional execution test */
233 rtx prob_val
; /* probability of branch taken. */
234 int mod_ok
; /* true if modifications ok last insn. */
236 int must_be_last
= FALSE
;
244 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
246 if (GET_CODE (insn
) == NOTE
)
249 if (GET_CODE (insn
) != INSN
&& GET_CODE (insn
) != CALL_INSN
)
252 /* Remove USE insns that get in the way. */
253 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
255 /* ??? Ug. Actually unlinking the thing is problematic,
256 given what we'd have to coordinate with our callers. */
257 PUT_CODE (insn
, NOTE
);
258 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
259 NOTE_SOURCE_FILE (insn
) = 0;
263 /* Last insn wasn't last? */
267 if (modified_in_p (test
, insn
))
274 /* Now build the conditional form of the instruction. */
275 pattern
= PATTERN (insn
);
276 xtest
= copy_rtx (test
);
278 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
280 if (GET_CODE (pattern
) == COND_EXEC
)
282 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
285 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
286 COND_EXEC_TEST (pattern
));
287 pattern
= COND_EXEC_CODE (pattern
);
290 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
292 /* If the machine needs to modify the insn being conditionally executed,
293 say for example to force a constant integer operand into a temp
294 register, do so here. */
295 #ifdef IFCVT_MODIFY_INSN
296 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
301 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
303 if (GET_CODE (insn
) == CALL_INSN
&& prob_val
)
304 validate_change (insn
, ®_NOTES (insn
),
305 alloc_EXPR_LIST (REG_BR_PROB
, prob_val
,
306 REG_NOTES (insn
)), 1);
316 /* Return the condition for a jump. Do not do any special processing. */
319 cond_exec_get_condition (jump
)
324 if (any_condjump_p (jump
))
325 test_if
= SET_SRC (pc_set (jump
));
328 cond
= XEXP (test_if
, 0);
330 /* If this branches to JUMP_LABEL when the condition is false,
331 reverse the condition. */
332 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
333 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
335 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
339 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
346 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
347 to conditional execution. Return TRUE if we were successful at
348 converting the block. */
351 cond_exec_process_if_block (ce_info
, do_multiple_p
)
352 ce_if_block_t
* ce_info
; /* if block information */
353 int do_multiple_p
; /* != 0 if we should handle && and || blocks */
355 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
356 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
357 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
358 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
359 rtx then_start
; /* first insn in THEN block */
360 rtx then_end
; /* last insn + 1 in THEN block */
361 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
362 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
363 int max
; /* max # of insns to convert. */
364 int then_mod_ok
; /* whether conditional mods are ok in THEN */
365 rtx true_expr
; /* test for else block insns */
366 rtx false_expr
; /* test for then block insns */
367 rtx true_prob_val
; /* probability of else block */
368 rtx false_prob_val
; /* probability of then block */
370 enum rtx_code false_code
;
372 /* If test is comprised of && or || elements, and we've failed at handling
373 all of them together, just use the last test if it is the special case of
374 && elements without an ELSE block. */
375 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
377 if (else_bb
|| ! ce_info
->and_and_p
)
380 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
381 ce_info
->num_multiple_test_blocks
= 0;
382 ce_info
->num_and_and_blocks
= 0;
383 ce_info
->num_or_or_blocks
= 0;
386 /* Find the conditional jump to the ELSE or JOIN part, and isolate
388 test_expr
= cond_exec_get_condition (test_bb
->end
);
392 /* If the conditional jump is more than just a conditional jump,
393 then we can not do conditional execution conversion on this block. */
394 if (! onlyjump_p (test_bb
->end
))
397 /* Collect the bounds of where we're to search, skipping any labels, jumps
398 and notes at the beginning and end of the block. Then count the total
399 number of insns and see if it is small enough to convert. */
400 then_start
= first_active_insn (then_bb
);
401 then_end
= last_active_insn (then_bb
, TRUE
);
402 n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
403 max
= MAX_CONDITIONAL_EXECUTE
;
408 else_start
= first_active_insn (else_bb
);
409 else_end
= last_active_insn (else_bb
, TRUE
);
410 n_insns
+= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
416 /* Map test_expr/test_jump into the appropriate MD tests to use on
417 the conditionally executed code. */
419 true_expr
= test_expr
;
421 false_code
= reversed_comparison_code (true_expr
, test_bb
->end
);
422 if (false_code
!= UNKNOWN
)
423 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
424 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
426 false_expr
= NULL_RTX
;
428 #ifdef IFCVT_MODIFY_TESTS
429 /* If the machine description needs to modify the tests, such as setting a
430 conditional execution register from a comparison, it can do so here. */
431 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
433 /* See if the conversion failed */
434 if (!true_expr
|| !false_expr
)
438 true_prob_val
= find_reg_note (test_bb
->end
, REG_BR_PROB
, NULL_RTX
);
441 true_prob_val
= XEXP (true_prob_val
, 0);
442 false_prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (true_prob_val
));
445 false_prob_val
= NULL_RTX
;
447 /* If we have && or || tests, do them here. These tests are in the adjacent
448 blocks after the first block containing the test. */
449 if (ce_info
->num_multiple_test_blocks
> 0)
451 basic_block bb
= test_bb
;
452 basic_block last_test_bb
= ce_info
->last_test_bb
;
462 bb
= block_fallthru (bb
);
463 start
= first_active_insn (bb
);
464 end
= last_active_insn (bb
, TRUE
);
466 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
467 false_prob_val
, FALSE
))
470 /* If the conditional jump is more than just a conditional jump, then
471 we can not do conditional execution conversion on this block. */
472 if (! onlyjump_p (bb
->end
))
475 /* Find the conditional jump and isolate the test. */
476 t
= cond_exec_get_condition (bb
->end
);
480 f
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (t
)),
485 if (ce_info
->and_and_p
)
487 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
488 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
492 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
493 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
496 /* If the machine description needs to modify the tests, such as
497 setting a conditional execution register from a comparison, it can
499 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
500 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
502 /* See if the conversion failed */
510 while (bb
!= last_test_bb
);
513 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
514 on then THEN block. */
515 then_mod_ok
= (else_bb
== NULL_BLOCK
);
517 /* Go through the THEN and ELSE blocks converting the insns if possible
518 to conditional execution. */
522 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
523 false_expr
, false_prob_val
,
527 if (else_bb
&& else_end
528 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
529 true_expr
, true_prob_val
, TRUE
))
532 /* If we cannot apply the changes, fail. Do not go through the normal fail
533 processing, since apply_change_group will call cancel_changes. */
534 if (! apply_change_group ())
536 #ifdef IFCVT_MODIFY_CANCEL
537 /* Cancel any machine dependent changes. */
538 IFCVT_MODIFY_CANCEL (ce_info
);
543 #ifdef IFCVT_MODIFY_FINAL
544 /* Do any machine dependent final modifications */
545 IFCVT_MODIFY_FINAL (ce_info
);
548 /* Conversion succeeded. */
550 fprintf (rtl_dump_file
, "%d insn%s converted to conditional execution.\n",
551 n_insns
, (n_insns
== 1) ? " was" : "s were");
553 /* Merge the blocks! */
554 merge_if_block (ce_info
);
555 cond_exec_changed_p
= TRUE
;
559 #ifdef IFCVT_MODIFY_CANCEL
560 /* Cancel any machine dependent changes. */
561 IFCVT_MODIFY_CANCEL (ce_info
);
568 /* Used by noce_process_if_block to communicate with its subroutines.
570 The subroutines know that A and B may be evaluated freely. They
571 know that X is a register. They should insert new instructions
572 before cond_earliest. */
579 rtx jump
, cond
, cond_earliest
;
582 static rtx noce_emit_store_flag
PARAMS ((struct noce_if_info
*,
584 static int noce_try_store_flag
PARAMS ((struct noce_if_info
*));
585 static int noce_try_addcc
PARAMS ((struct noce_if_info
*));
586 static int noce_try_store_flag_constants
PARAMS ((struct noce_if_info
*));
587 static int noce_try_store_flag_mask
PARAMS ((struct noce_if_info
*));
588 static rtx noce_emit_cmove
PARAMS ((struct noce_if_info
*,
589 rtx
, enum rtx_code
, rtx
,
591 static int noce_try_cmove
PARAMS ((struct noce_if_info
*));
592 static int noce_try_cmove_arith
PARAMS ((struct noce_if_info
*));
593 static rtx noce_get_alt_condition
PARAMS ((struct noce_if_info
*,
595 static int noce_try_minmax
PARAMS ((struct noce_if_info
*));
596 static int noce_try_abs
PARAMS ((struct noce_if_info
*));
598 /* Helper function for noce_try_store_flag*. */
601 noce_emit_store_flag (if_info
, x
, reversep
, normalize
)
602 struct noce_if_info
*if_info
;
604 int reversep
, normalize
;
606 rtx cond
= if_info
->cond
;
610 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
611 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
613 /* If earliest == jump, or when the condition is complex, try to
614 build the store_flag insn directly. */
617 cond
= XEXP (SET_SRC (pc_set (if_info
->jump
)), 0);
620 code
= reversed_comparison_code (cond
, if_info
->jump
);
622 code
= GET_CODE (cond
);
624 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
625 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
629 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
631 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
634 tmp
= emit_insn (tmp
);
636 if (recog_memoized (tmp
) >= 0)
642 if_info
->cond_earliest
= if_info
->jump
;
650 /* Don't even try if the comparison operands or the mode of X are weird. */
651 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
654 return emit_store_flag (x
, code
, XEXP (cond
, 0),
655 XEXP (cond
, 1), VOIDmode
,
656 (code
== LTU
|| code
== LEU
657 || code
== GEU
|| code
== GTU
), normalize
);
660 /* Emit instruction to move an rtx into STRICT_LOW_PART. */
662 noce_emit_move_insn (x
, y
)
665 enum machine_mode outmode
, inmode
;
669 if (GET_CODE (x
) != STRICT_LOW_PART
)
671 emit_move_insn (x
, y
);
676 inner
= XEXP (outer
, 0);
677 outmode
= GET_MODE (outer
);
678 inmode
= GET_MODE (inner
);
679 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
680 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
, outmode
, y
,
681 GET_MODE_BITSIZE (inmode
));
684 /* Convert "if (test) x = 1; else x = 0".
686 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
687 tried in noce_try_store_flag_constants after noce_try_cmove has had
688 a go at the conversion. */
691 noce_try_store_flag (if_info
)
692 struct noce_if_info
*if_info
;
697 if (GET_CODE (if_info
->b
) == CONST_INT
698 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
699 && if_info
->a
== const0_rtx
)
701 else if (if_info
->b
== const0_rtx
702 && GET_CODE (if_info
->a
) == CONST_INT
703 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
704 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
712 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
715 if (target
!= if_info
->x
)
716 noce_emit_move_insn (if_info
->x
, target
);
720 emit_insn_before_scope (seq
, if_info
->jump
, INSN_SCOPE (if_info
->insn_a
));
731 /* Convert "if (test) x = a; else x = b", for A and B constant. */
734 noce_try_store_flag_constants (if_info
)
735 struct noce_if_info
*if_info
;
739 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
740 int normalize
, can_reverse
;
741 enum machine_mode mode
;
744 && GET_CODE (if_info
->a
) == CONST_INT
745 && GET_CODE (if_info
->b
) == CONST_INT
)
747 mode
= GET_MODE (if_info
->x
);
748 ifalse
= INTVAL (if_info
->a
);
749 itrue
= INTVAL (if_info
->b
);
751 /* Make sure we can represent the difference between the two values. */
752 if ((itrue
- ifalse
> 0)
753 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
756 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
758 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
762 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
764 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
765 && (STORE_FLAG_VALUE
== 1
766 || BRANCH_COST
>= 2))
768 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
769 && (STORE_FLAG_VALUE
== 1 || BRANCH_COST
>= 2))
770 normalize
= 1, reversep
= 1;
772 && (STORE_FLAG_VALUE
== -1
773 || BRANCH_COST
>= 2))
775 else if (ifalse
== -1 && can_reverse
776 && (STORE_FLAG_VALUE
== -1 || BRANCH_COST
>= 2))
777 normalize
= -1, reversep
= 1;
778 else if ((BRANCH_COST
>= 2 && STORE_FLAG_VALUE
== -1)
786 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
787 diff
= trunc_int_for_mode (-diff
, mode
);
791 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
798 /* if (test) x = 3; else x = 4;
799 => x = 3 + (test == 0); */
800 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
802 target
= expand_simple_binop (mode
,
803 (diff
== STORE_FLAG_VALUE
805 GEN_INT (ifalse
), target
, if_info
->x
, 0,
809 /* if (test) x = 8; else x = 0;
810 => x = (test != 0) << 3; */
811 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
813 target
= expand_simple_binop (mode
, ASHIFT
,
814 target
, GEN_INT (tmp
), if_info
->x
, 0,
818 /* if (test) x = -1; else x = b;
819 => x = -(test != 0) | b; */
820 else if (itrue
== -1)
822 target
= expand_simple_binop (mode
, IOR
,
823 target
, GEN_INT (ifalse
), if_info
->x
, 0,
827 /* if (test) x = a; else x = b;
828 => x = (-(test != 0) & (b - a)) + a; */
831 target
= expand_simple_binop (mode
, AND
,
832 target
, GEN_INT (diff
), if_info
->x
, 0,
835 target
= expand_simple_binop (mode
, PLUS
,
836 target
, GEN_INT (ifalse
),
837 if_info
->x
, 0, OPTAB_WIDEN
);
846 if (target
!= if_info
->x
)
847 noce_emit_move_insn (if_info
->x
, target
);
852 if (seq_contains_jump (seq
))
855 emit_insn_before_scope (seq
, if_info
->jump
, INSN_SCOPE (if_info
->insn_a
));
863 /* Convert "if (test) foo++" into "foo += (test != 0)", and
864 similarly for "foo--". */
867 noce_try_addcc (if_info
)
868 struct noce_if_info
*if_info
;
871 int subtract
, normalize
;
874 /* Should be no `else' case to worry about. */
875 && if_info
->b
== if_info
->x
876 && GET_CODE (if_info
->a
) == PLUS
877 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->x
)
878 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
881 rtx cond
= if_info
->cond
;
882 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
884 /* First try to use addcc pattern. */
885 if (general_operand (XEXP (cond
, 0), VOIDmode
)
886 && general_operand (XEXP (cond
, 1), VOIDmode
))
889 target
= emit_conditional_add (if_info
->x
, code
,
890 XEXP (cond
, 0), XEXP (cond
, 1),
892 if_info
->b
, XEXP (if_info
->a
, 1),
893 GET_MODE (if_info
->x
),
894 (code
== LTU
|| code
== GEU
895 || code
== LEU
|| code
== GTU
));
898 if (target
!= if_info
->x
)
899 noce_emit_move_insn (if_info
->x
, target
);
903 emit_insn_before_scope (seq
, if_info
->jump
,
904 INSN_SCOPE (if_info
->insn_a
));
910 /* If that fails, construct conditional increment or decrement using
913 && (XEXP (if_info
->a
, 1) == const1_rtx
914 || XEXP (if_info
->a
, 1) == constm1_rtx
))
917 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
918 subtract
= 0, normalize
= 0;
919 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
920 subtract
= 1, normalize
= 0;
922 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
925 target
= noce_emit_store_flag (if_info
,
926 gen_reg_rtx (GET_MODE (if_info
->x
)),
930 target
= expand_simple_binop (GET_MODE (if_info
->x
),
931 subtract
? MINUS
: PLUS
,
932 if_info
->x
, target
, if_info
->x
,
936 if (target
!= if_info
->x
)
937 noce_emit_move_insn (if_info
->x
, target
);
942 if (seq_contains_jump (seq
))
945 emit_insn_before_scope (seq
, if_info
->jump
,
946 INSN_SCOPE (if_info
->insn_a
));
957 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
960 noce_try_store_flag_mask (if_info
)
961 struct noce_if_info
*if_info
;
969 || STORE_FLAG_VALUE
== -1)
970 && ((if_info
->a
== const0_rtx
971 && rtx_equal_p (if_info
->b
, if_info
->x
))
972 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
975 && if_info
->b
== const0_rtx
976 && rtx_equal_p (if_info
->a
, if_info
->x
))))
979 target
= noce_emit_store_flag (if_info
,
980 gen_reg_rtx (GET_MODE (if_info
->x
)),
983 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
984 if_info
->x
, target
, if_info
->x
, 0,
989 if (target
!= if_info
->x
)
990 noce_emit_move_insn (if_info
->x
, target
);
995 if (seq_contains_jump (seq
))
998 emit_insn_before_scope (seq
, if_info
->jump
,
999 INSN_SCOPE (if_info
->insn_a
));
1010 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1013 noce_emit_cmove (if_info
, x
, code
, cmp_a
, cmp_b
, vfalse
, vtrue
)
1014 struct noce_if_info
*if_info
;
1015 rtx x
, cmp_a
, cmp_b
, vfalse
, vtrue
;
1018 /* If earliest == jump, try to build the cmove insn directly.
1019 This is helpful when combine has created some complex condition
1020 (like for alpha's cmovlbs) that we can't hope to regenerate
1021 through the normal interface. */
1023 if (if_info
->cond_earliest
== if_info
->jump
)
1027 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1028 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
1029 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
1032 tmp
= emit_insn (tmp
);
1034 if (recog_memoized (tmp
) >= 0)
1046 /* Don't even try if the comparison operands are weird. */
1047 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1048 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1051 #if HAVE_conditional_move
1052 return emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1053 vtrue
, vfalse
, GET_MODE (x
),
1054 (code
== LTU
|| code
== GEU
1055 || code
== LEU
|| code
== GTU
));
1057 /* We'll never get here, as noce_process_if_block doesn't call the
1058 functions involved. Ifdef code, however, should be discouraged
1059 because it leads to typos in the code not selected. However,
1060 emit_conditional_move won't exist either. */
1065 /* Try only simple constants and registers here. More complex cases
1066 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1067 has had a go at it. */
1070 noce_try_cmove (if_info
)
1071 struct noce_if_info
*if_info
;
1076 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1077 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1081 code
= GET_CODE (if_info
->cond
);
1082 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1083 XEXP (if_info
->cond
, 0),
1084 XEXP (if_info
->cond
, 1),
1085 if_info
->a
, if_info
->b
);
1089 if (target
!= if_info
->x
)
1090 noce_emit_move_insn (if_info
->x
, target
);
1094 emit_insn_before_scope (seq
, if_info
->jump
,
1095 INSN_SCOPE (if_info
->insn_a
));
1108 /* Try more complex cases involving conditional_move. */
1111 noce_try_cmove_arith (if_info
)
1112 struct noce_if_info
*if_info
;
1122 /* A conditional move from two memory sources is equivalent to a
1123 conditional on their addresses followed by a load. Don't do this
1124 early because it'll screw alias analysis. Note that we've
1125 already checked for no side effects. */
1126 if (! no_new_pseudos
&& cse_not_expected
1127 && GET_CODE (a
) == MEM
&& GET_CODE (b
) == MEM
1128 && BRANCH_COST
>= 5)
1132 x
= gen_reg_rtx (Pmode
);
1136 /* ??? We could handle this if we knew that a load from A or B could
1137 not fault. This is also true if we've already loaded
1138 from the address along the path from ENTRY. */
1139 else if (may_trap_p (a
) || may_trap_p (b
))
1142 /* if (test) x = a + b; else x = c - d;
1149 code
= GET_CODE (if_info
->cond
);
1150 insn_a
= if_info
->insn_a
;
1151 insn_b
= if_info
->insn_b
;
1153 /* Possibly rearrange operands to make things come out more natural. */
1154 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1157 if (rtx_equal_p (b
, x
))
1159 else if (general_operand (b
, GET_MODE (b
)))
1164 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1165 tmp
= a
, a
= b
, b
= tmp
;
1166 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1172 /* If either operand is complex, load it into a register first.
1173 The best way to do this is to copy the original insn. In this
1174 way we preserve any clobbers etc that the insn may have had.
1175 This is of course not possible in the IS_MEM case. */
1176 if (! general_operand (a
, GET_MODE (a
)))
1181 goto end_seq_and_fail
;
1185 tmp
= gen_reg_rtx (GET_MODE (a
));
1186 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1189 goto end_seq_and_fail
;
1192 a
= gen_reg_rtx (GET_MODE (a
));
1193 tmp
= copy_rtx (insn_a
);
1194 set
= single_set (tmp
);
1196 tmp
= emit_insn (PATTERN (tmp
));
1198 if (recog_memoized (tmp
) < 0)
1199 goto end_seq_and_fail
;
1201 if (! general_operand (b
, GET_MODE (b
)))
1206 goto end_seq_and_fail
;
1210 tmp
= gen_reg_rtx (GET_MODE (b
));
1211 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, b
));
1214 goto end_seq_and_fail
;
1217 b
= gen_reg_rtx (GET_MODE (b
));
1218 tmp
= copy_rtx (insn_b
);
1219 set
= single_set (tmp
);
1221 tmp
= emit_insn (PATTERN (tmp
));
1223 if (recog_memoized (tmp
) < 0)
1224 goto end_seq_and_fail
;
1227 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1228 XEXP (if_info
->cond
, 1), a
, b
);
1231 goto end_seq_and_fail
;
1233 /* If we're handling a memory for above, emit the load now. */
1236 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1238 /* Copy over flags as appropriate. */
1239 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1240 MEM_VOLATILE_P (tmp
) = 1;
1241 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1242 MEM_IN_STRUCT_P (tmp
) = 1;
1243 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1244 MEM_SCALAR_P (tmp
) = 1;
1245 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1246 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1248 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1250 noce_emit_move_insn (if_info
->x
, tmp
);
1252 else if (target
!= x
)
1253 noce_emit_move_insn (x
, target
);
1257 emit_insn_before_scope (tmp
, if_info
->jump
, INSN_SCOPE (if_info
->insn_a
));
1265 /* For most cases, the simplified condition we found is the best
1266 choice, but this is not the case for the min/max/abs transforms.
1267 For these we wish to know that it is A or B in the condition. */
1270 noce_get_alt_condition (if_info
, target
, earliest
)
1271 struct noce_if_info
*if_info
;
1275 rtx cond
, set
, insn
;
1278 /* If target is already mentioned in the known condition, return it. */
1279 if (reg_mentioned_p (target
, if_info
->cond
))
1281 *earliest
= if_info
->cond_earliest
;
1282 return if_info
->cond
;
1285 set
= pc_set (if_info
->jump
);
1286 cond
= XEXP (SET_SRC (set
), 0);
1288 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1289 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1291 /* If we're looking for a constant, try to make the conditional
1292 have that constant in it. There are two reasons why it may
1293 not have the constant we want:
1295 1. GCC may have needed to put the constant in a register, because
1296 the target can't compare directly against that constant. For
1297 this case, we look for a SET immediately before the comparison
1298 that puts a constant in that register.
1300 2. GCC may have canonicalized the conditional, for example
1301 replacing "if x < 4" with "if x <= 3". We can undo that (or
1302 make equivalent types of changes) to get the constants we need
1303 if they're off by one in the right direction. */
1305 if (GET_CODE (target
) == CONST_INT
)
1307 enum rtx_code code
= GET_CODE (if_info
->cond
);
1308 rtx op_a
= XEXP (if_info
->cond
, 0);
1309 rtx op_b
= XEXP (if_info
->cond
, 1);
1312 /* First, look to see if we put a constant in a register. */
1313 prev_insn
= PREV_INSN (if_info
->cond_earliest
);
1315 && INSN_P (prev_insn
)
1316 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1318 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1320 src
= SET_SRC (PATTERN (prev_insn
));
1321 if (GET_CODE (src
) == CONST_INT
)
1323 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1325 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1328 if (GET_CODE (op_a
) == CONST_INT
)
1333 code
= swap_condition (code
);
1338 /* Now, look to see if we can get the right constant by
1339 adjusting the conditional. */
1340 if (GET_CODE (op_b
) == CONST_INT
)
1342 HOST_WIDE_INT desired_val
= INTVAL (target
);
1343 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1348 if (actual_val
== desired_val
+ 1)
1351 op_b
= GEN_INT (desired_val
);
1355 if (actual_val
== desired_val
- 1)
1358 op_b
= GEN_INT (desired_val
);
1362 if (actual_val
== desired_val
- 1)
1365 op_b
= GEN_INT (desired_val
);
1369 if (actual_val
== desired_val
+ 1)
1372 op_b
= GEN_INT (desired_val
);
1380 /* If we made any changes, generate a new conditional that is
1381 equivalent to what we started with, but has the right
1383 if (code
!= GET_CODE (if_info
->cond
)
1384 || op_a
!= XEXP (if_info
->cond
, 0)
1385 || op_b
!= XEXP (if_info
->cond
, 1))
1387 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1388 *earliest
= if_info
->cond_earliest
;
1393 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1395 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1398 /* We almost certainly searched back to a different place.
1399 Need to re-verify correct lifetimes. */
1401 /* X may not be mentioned in the range (cond_earliest, jump]. */
1402 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1403 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1406 /* A and B may not be modified in the range [cond_earliest, jump). */
1407 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1409 && (modified_in_p (if_info
->a
, insn
)
1410 || modified_in_p (if_info
->b
, insn
)))
1416 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1419 noce_try_minmax (if_info
)
1420 struct noce_if_info
*if_info
;
1422 rtx cond
, earliest
, target
, seq
;
1423 enum rtx_code code
, op
;
1426 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1430 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1431 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1432 to get the target to tell us... */
1433 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1434 || HONOR_NANS (GET_MODE (if_info
->x
)))
1437 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1441 /* Verify the condition is of the form we expect, and canonicalize
1442 the comparison code. */
1443 code
= GET_CODE (cond
);
1444 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1446 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1449 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1451 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1453 code
= swap_condition (code
);
1458 /* Determine what sort of operation this is. Note that the code is for
1459 a taken branch, so the code->operation mapping appears backwards. */
1492 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1493 if_info
->a
, if_info
->b
,
1494 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1500 if (target
!= if_info
->x
)
1501 noce_emit_move_insn (if_info
->x
, target
);
1506 if (seq_contains_jump (seq
))
1509 emit_insn_before_scope (seq
, if_info
->jump
, INSN_SCOPE (if_info
->insn_a
));
1510 if_info
->cond
= cond
;
1511 if_info
->cond_earliest
= earliest
;
1516 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1519 noce_try_abs (if_info
)
1520 struct noce_if_info
*if_info
;
1522 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1525 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1529 /* Recognize A and B as constituting an ABS or NABS. */
1532 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1534 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1536 c
= a
; a
= b
; b
= c
;
1542 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1546 /* Verify the condition is of the form we expect. */
1547 if (rtx_equal_p (XEXP (cond
, 0), b
))
1549 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1554 /* Verify that C is zero. Search backward through the block for
1555 a REG_EQUAL note if necessary. */
1558 rtx insn
, note
= NULL
;
1559 for (insn
= earliest
;
1560 insn
!= if_info
->test_bb
->head
;
1561 insn
= PREV_INSN (insn
))
1563 && ((note
= find_reg_note (insn
, REG_EQUAL
, c
))
1564 || (note
= find_reg_note (insn
, REG_EQUIV
, c
))))
1570 if (GET_CODE (c
) == MEM
1571 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
1572 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
1573 c
= get_pool_constant (XEXP (c
, 0));
1575 /* Work around funny ideas get_condition has wrt canonicalization.
1576 Note that these rtx constants are known to be CONST_INT, and
1577 therefore imply integer comparisons. */
1578 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
1580 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
1582 else if (c
!= CONST0_RTX (GET_MODE (b
)))
1585 /* Determine what sort of operation this is. */
1586 switch (GET_CODE (cond
))
1605 target
= expand_simple_unop (GET_MODE (if_info
->x
), ABS
, b
, if_info
->x
, 0);
1607 /* ??? It's a quandry whether cmove would be better here, especially
1608 for integers. Perhaps combine will clean things up. */
1609 if (target
&& negate
)
1610 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
, if_info
->x
, 0);
1618 if (target
!= if_info
->x
)
1619 noce_emit_move_insn (if_info
->x
, target
);
1624 if (seq_contains_jump (seq
))
1627 emit_insn_before_scope (seq
, if_info
->jump
, INSN_SCOPE (if_info
->insn_a
));
1628 if_info
->cond
= cond
;
1629 if_info
->cond_earliest
= earliest
;
1634 /* Similar to get_condition, only the resulting condition must be
1635 valid at JUMP, instead of at EARLIEST. */
1638 noce_get_condition (jump
, earliest
)
1642 rtx cond
, set
, tmp
, insn
;
1645 if (! any_condjump_p (jump
))
1648 set
= pc_set (jump
);
1650 /* If this branches to JUMP_LABEL when the condition is false,
1651 reverse the condition. */
1652 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1653 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
1655 /* If the condition variable is a register and is MODE_INT, accept it. */
1657 cond
= XEXP (SET_SRC (set
), 0);
1658 tmp
= XEXP (cond
, 0);
1659 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
)
1664 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
1665 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
1669 /* Otherwise, fall back on canonicalize_condition to do the dirty
1670 work of manipulating MODE_CC values and COMPARE rtx codes. */
1672 tmp
= canonicalize_condition (jump
, cond
, reverse
, earliest
, NULL_RTX
);
1676 /* We are going to insert code before JUMP, not before EARLIEST.
1677 We must therefore be certain that the given condition is valid
1678 at JUMP by virtue of not having been modified since. */
1679 for (insn
= *earliest
; insn
!= jump
; insn
= NEXT_INSN (insn
))
1680 if (INSN_P (insn
) && modified_in_p (tmp
, insn
))
1685 /* The condition was modified. See if we can get a partial result
1686 that doesn't follow all the reversals. Perhaps combine can fold
1687 them together later. */
1688 tmp
= XEXP (tmp
, 0);
1689 if (!REG_P (tmp
) || GET_MODE_CLASS (GET_MODE (tmp
)) != MODE_INT
)
1691 tmp
= canonicalize_condition (jump
, cond
, reverse
, earliest
, tmp
);
1695 /* For sanity's sake, re-validate the new result. */
1696 for (insn
= *earliest
; insn
!= jump
; insn
= NEXT_INSN (insn
))
1697 if (INSN_P (insn
) && modified_in_p (tmp
, insn
))
1703 /* Return true if OP is ok for if-then-else processing. */
1706 noce_operand_ok (op
)
1709 /* We special-case memories, so handle any of them with
1710 no address side effects. */
1711 if (GET_CODE (op
) == MEM
)
1712 return ! side_effects_p (XEXP (op
, 0));
1714 if (side_effects_p (op
))
1717 return ! may_trap_p (op
);
1720 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
1721 without using conditional execution. Return TRUE if we were
1722 successful at converting the block. */
1725 noce_process_if_block (ce_info
)
1726 struct ce_if_block
* ce_info
;
1728 basic_block test_bb
= ce_info
->test_bb
; /* test block */
1729 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
1730 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
1731 struct noce_if_info if_info
;
1734 rtx orig_x
, x
, a
, b
;
1737 /* We're looking for patterns of the form
1739 (1) if (...) x = a; else x = b;
1740 (2) x = b; if (...) x = a;
1741 (3) if (...) x = a; // as if with an initial x = x.
1743 The later patterns require jumps to be more expensive.
1745 ??? For future expansion, look for multiple X in such patterns. */
1747 /* If test is comprised of && or || elements, don't handle it unless it is
1748 the special case of && elements without an ELSE block. */
1749 if (ce_info
->num_multiple_test_blocks
)
1751 if (else_bb
|| ! ce_info
->and_and_p
)
1754 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
1755 ce_info
->num_multiple_test_blocks
= 0;
1756 ce_info
->num_and_and_blocks
= 0;
1757 ce_info
->num_or_or_blocks
= 0;
1760 /* If this is not a standard conditional jump, we can't parse it. */
1761 jump
= test_bb
->end
;
1762 cond
= noce_get_condition (jump
, &if_info
.cond_earliest
);
1766 /* If the conditional jump is more than just a conditional
1767 jump, then we can not do if-conversion on this block. */
1768 if (! onlyjump_p (jump
))
1771 /* We must be comparing objects whose modes imply the size. */
1772 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
1775 /* Look for one of the potential sets. */
1776 insn_a
= first_active_insn (then_bb
);
1778 || insn_a
!= last_active_insn (then_bb
, FALSE
)
1779 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
1782 x
= SET_DEST (set_a
);
1783 a
= SET_SRC (set_a
);
1785 /* Look for the other potential set. Make sure we've got equivalent
1787 /* ??? This is overconservative. Storing to two different mems is
1788 as easy as conditionally computing the address. Storing to a
1789 single mem merely requires a scratch memory to use as one of the
1790 destination addresses; often the memory immediately below the
1791 stack pointer is available for this. */
1795 insn_b
= first_active_insn (else_bb
);
1797 || insn_b
!= last_active_insn (else_bb
, FALSE
)
1798 || (set_b
= single_set (insn_b
)) == NULL_RTX
1799 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
1804 insn_b
= prev_nonnote_insn (if_info
.cond_earliest
);
1806 || GET_CODE (insn_b
) != INSN
1807 || (set_b
= single_set (insn_b
)) == NULL_RTX
1808 || ! rtx_equal_p (x
, SET_DEST (set_b
))
1809 || reg_overlap_mentioned_p (x
, cond
)
1810 || reg_overlap_mentioned_p (x
, a
)
1811 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
1812 || modified_between_p (x
, if_info
.cond_earliest
, NEXT_INSN (jump
)))
1813 insn_b
= set_b
= NULL_RTX
;
1815 b
= (set_b
? SET_SRC (set_b
) : x
);
1817 /* Only operate on register destinations, and even then avoid extending
1818 the lifetime of hard registers on small register class machines. */
1820 if (GET_CODE (x
) != REG
1821 || (SMALL_REGISTER_CLASSES
1822 && REGNO (x
) < FIRST_PSEUDO_REGISTER
))
1826 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
1827 ? XEXP (x
, 0) : x
));
1830 /* Don't operate on sources that may trap or are volatile. */
1831 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
1834 /* Set up the info block for our subroutines. */
1835 if_info
.test_bb
= test_bb
;
1836 if_info
.cond
= cond
;
1837 if_info
.jump
= jump
;
1838 if_info
.insn_a
= insn_a
;
1839 if_info
.insn_b
= insn_b
;
1844 /* Try optimizations in some approximation of a useful order. */
1845 /* ??? Should first look to see if X is live incoming at all. If it
1846 isn't, we don't need anything but an unconditional set. */
1848 /* Look and see if A and B are really the same. Avoid creating silly
1849 cmove constructs that no one will fix up later. */
1850 if (rtx_equal_p (a
, b
))
1852 /* If we have an INSN_B, we don't have to create any new rtl. Just
1853 move the instruction that we already have. If we don't have an
1854 INSN_B, that means that A == X, and we've got a noop move. In
1855 that case don't do anything and let the code below delete INSN_A. */
1856 if (insn_b
&& else_bb
)
1860 if (else_bb
&& insn_b
== else_bb
->end
)
1861 else_bb
->end
= PREV_INSN (insn_b
);
1862 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
1864 /* If there was a REG_EQUAL note, delete it since it may have been
1865 true due to this insn being after a jump. */
1866 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
1867 remove_note (insn_b
, note
);
1871 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
1872 x must be executed twice. */
1873 else if (insn_b
&& side_effects_p (orig_x
))
1880 if (noce_try_store_flag (&if_info
))
1882 if (noce_try_minmax (&if_info
))
1884 if (noce_try_abs (&if_info
))
1886 if (HAVE_conditional_move
1887 && noce_try_cmove (&if_info
))
1889 if (! HAVE_conditional_execution
)
1891 if (noce_try_store_flag_constants (&if_info
))
1893 if (noce_try_addcc (&if_info
))
1895 if (noce_try_store_flag_mask (&if_info
))
1897 if (HAVE_conditional_move
1898 && noce_try_cmove_arith (&if_info
))
1905 /* The original sets may now be killed. */
1906 delete_insn (insn_a
);
1908 /* Several special cases here: First, we may have reused insn_b above,
1909 in which case insn_b is now NULL. Second, we want to delete insn_b
1910 if it came from the ELSE block, because follows the now correct
1911 write that appears in the TEST block. However, if we got insn_b from
1912 the TEST block, it may in fact be loading data needed for the comparison.
1913 We'll let life_analysis remove the insn if it's really dead. */
1914 if (insn_b
&& else_bb
)
1915 delete_insn (insn_b
);
1917 /* The new insns will have been inserted immediately before the jump. We
1918 should be able to remove the jump with impunity, but the condition itself
1919 may have been modified by gcse to be shared across basic blocks. */
1922 /* If we used a temporary, fix it up now. */
1926 noce_emit_move_insn (copy_rtx (orig_x
), x
);
1927 insn_b
= get_insns ();
1930 emit_insn_after_scope (insn_b
, test_bb
->end
, INSN_SCOPE (insn_a
));
1933 /* Merge the blocks! */
1934 merge_if_block (ce_info
);
1939 /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
1940 straight line code. Return true if successful. */
1943 process_if_block (ce_info
)
1944 struct ce_if_block
* ce_info
;
1946 if (! reload_completed
1947 && noce_process_if_block (ce_info
))
1950 if (HAVE_conditional_execution
&& reload_completed
)
1952 /* If we have && and || tests, try to first handle combining the && and
1953 || tests into the conditional code, and if that fails, go back and
1954 handle it without the && and ||, which at present handles the && case
1955 if there was no ELSE block. */
1956 if (cond_exec_process_if_block (ce_info
, TRUE
))
1959 if (ce_info
->num_multiple_test_blocks
)
1963 if (cond_exec_process_if_block (ce_info
, FALSE
))
1971 /* Merge the blocks and mark for local life update. */
1974 merge_if_block (ce_info
)
1975 struct ce_if_block
* ce_info
;
1977 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
1978 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
1979 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
1980 basic_block join_bb
= ce_info
->join_bb
; /* join block */
1981 basic_block combo_bb
;
1983 /* All block merging is done into the lower block numbers. */
1987 /* Merge any basic blocks to handle && and || subtests. Each of
1988 the blocks are on the fallthru path from the predecessor block. */
1989 if (ce_info
->num_multiple_test_blocks
> 0)
1991 basic_block bb
= test_bb
;
1992 basic_block last_test_bb
= ce_info
->last_test_bb
;
1993 basic_block fallthru
= block_fallthru (bb
);
1998 fallthru
= block_fallthru (bb
);
1999 if (post_dominators
)
2000 delete_from_dominance_info (post_dominators
, bb
);
2001 merge_blocks_nomove (combo_bb
, bb
);
2002 num_removed_blocks
++;
2004 while (bb
!= last_test_bb
);
2007 /* Merge TEST block into THEN block. Normally the THEN block won't have a
2008 label, but it might if there were || tests. That label's count should be
2009 zero, and it normally should be removed. */
2013 if (combo_bb
->global_live_at_end
)
2014 COPY_REG_SET (combo_bb
->global_live_at_end
,
2015 then_bb
->global_live_at_end
);
2016 if (post_dominators
)
2017 delete_from_dominance_info (post_dominators
, then_bb
);
2018 merge_blocks_nomove (combo_bb
, then_bb
);
2019 num_removed_blocks
++;
2022 /* The ELSE block, if it existed, had a label. That label count
2023 will almost always be zero, but odd things can happen when labels
2024 get their addresses taken. */
2027 if (post_dominators
)
2028 delete_from_dominance_info (post_dominators
, else_bb
);
2029 merge_blocks_nomove (combo_bb
, else_bb
);
2030 num_removed_blocks
++;
2033 /* If there was no join block reported, that means it was not adjacent
2034 to the others, and so we cannot merge them. */
2038 rtx last
= combo_bb
->end
;
2040 /* The outgoing edge for the current COMBO block should already
2041 be correct. Verify this. */
2042 if (combo_bb
->succ
== NULL_EDGE
)
2044 if (find_reg_note (last
, REG_NORETURN
, NULL
))
2046 else if (GET_CODE (last
) == INSN
2047 && GET_CODE (PATTERN (last
)) == TRAP_IF
2048 && TRAP_CONDITION (PATTERN (last
)) == const_true_rtx
)
2054 /* There should still be something at the end of the THEN or ELSE
2055 blocks taking us to our final destination. */
2056 else if (GET_CODE (last
) == JUMP_INSN
)
2058 else if (combo_bb
->succ
->dest
== EXIT_BLOCK_PTR
2059 && GET_CODE (last
) == CALL_INSN
2060 && SIBLING_CALL_P (last
))
2062 else if ((combo_bb
->succ
->flags
& EDGE_EH
)
2063 && can_throw_internal (last
))
2069 /* The JOIN block may have had quite a number of other predecessors too.
2070 Since we've already merged the TEST, THEN and ELSE blocks, we should
2071 have only one remaining edge from our if-then-else diamond. If there
2072 is more than one remaining edge, it must come from elsewhere. There
2073 may be zero incoming edges if the THEN block didn't actually join
2074 back up (as with a call to abort). */
2075 else if ((join_bb
->pred
== NULL
2076 || join_bb
->pred
->pred_next
== NULL
)
2077 && join_bb
!= EXIT_BLOCK_PTR
)
2079 /* We can merge the JOIN. */
2080 if (combo_bb
->global_live_at_end
)
2081 COPY_REG_SET (combo_bb
->global_live_at_end
,
2082 join_bb
->global_live_at_end
);
2084 if (post_dominators
)
2085 delete_from_dominance_info (post_dominators
, join_bb
);
2086 merge_blocks_nomove (combo_bb
, join_bb
);
2087 num_removed_blocks
++;
2091 /* We cannot merge the JOIN. */
2093 /* The outgoing edge for the current COMBO block should already
2094 be correct. Verify this. */
2095 if (combo_bb
->succ
->succ_next
!= NULL_EDGE
2096 || combo_bb
->succ
->dest
!= join_bb
)
2099 /* Remove the jump and cruft from the end of the COMBO block. */
2100 if (join_bb
!= EXIT_BLOCK_PTR
)
2101 tidy_fallthru_edge (combo_bb
->succ
, combo_bb
, join_bb
);
2104 num_updated_if_blocks
++;
2107 /* Find a block ending in a simple IF condition and try to transform it
2108 in some way. When converting a multi-block condition, put the new code
2109 in the first such block and delete the rest. Return a pointer to this
2110 first block if some transformation was done. Return NULL otherwise. */
2113 find_if_header (test_bb
, pass
)
2114 basic_block test_bb
;
2117 ce_if_block_t ce_info
;
2121 /* The kind of block we're looking for has exactly two successors. */
2122 if ((then_edge
= test_bb
->succ
) == NULL_EDGE
2123 || (else_edge
= then_edge
->succ_next
) == NULL_EDGE
2124 || else_edge
->succ_next
!= NULL_EDGE
)
2127 /* Neither edge should be abnormal. */
2128 if ((then_edge
->flags
& EDGE_COMPLEX
)
2129 || (else_edge
->flags
& EDGE_COMPLEX
))
2132 /* The THEN edge is canonically the one that falls through. */
2133 if (then_edge
->flags
& EDGE_FALLTHRU
)
2135 else if (else_edge
->flags
& EDGE_FALLTHRU
)
2138 else_edge
= then_edge
;
2142 /* Otherwise this must be a multiway branch of some sort. */
2145 memset ((PTR
) &ce_info
, '\0', sizeof (ce_info
));
2146 ce_info
.test_bb
= test_bb
;
2147 ce_info
.then_bb
= then_edge
->dest
;
2148 ce_info
.else_bb
= else_edge
->dest
;
2149 ce_info
.pass
= pass
;
2151 #ifdef IFCVT_INIT_EXTRA_FIELDS
2152 IFCVT_INIT_EXTRA_FIELDS (&ce_info
);
2155 if (find_if_block (&ce_info
))
2158 if (HAVE_trap
&& HAVE_conditional_trap
2159 && find_cond_trap (test_bb
, then_edge
, else_edge
))
2163 && (! HAVE_conditional_execution
|| reload_completed
))
2165 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
2167 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
2175 fprintf (rtl_dump_file
, "Conversion succeeded on pass %d.\n", pass
);
2176 return ce_info
.test_bb
;
2179 /* Return true if a block has two edges, one of which falls through to the next
2180 block, and the other jumps to a specific block, so that we can tell if the
2181 block is part of an && test or an || test. Returns either -1 or the number
2182 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
2185 block_jumps_and_fallthru_p (cur_bb
, target_bb
)
2187 basic_block target_bb
;
2190 int fallthru_p
= FALSE
;
2196 if (!cur_bb
|| !target_bb
)
2199 /* If no edges, obviously it doesn't jump or fallthru. */
2200 if (cur_bb
->succ
== NULL_EDGE
)
2203 for (cur_edge
= cur_bb
->succ
;
2204 cur_edge
!= NULL_EDGE
;
2205 cur_edge
= cur_edge
->succ_next
)
2207 if (cur_edge
->flags
& EDGE_COMPLEX
)
2208 /* Anything complex isn't what we want. */
2211 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
2214 else if (cur_edge
->dest
== target_bb
)
2221 if ((jump_p
& fallthru_p
) == 0)
2224 /* Don't allow calls in the block, since this is used to group && and ||
2225 together for conditional execution support. ??? we should support
2226 conditional execution support across calls for IA-64 some day, but
2227 for now it makes the code simpler. */
2229 insn
= cur_bb
->head
;
2231 while (insn
!= NULL_RTX
)
2233 if (GET_CODE (insn
) == CALL_INSN
)
2237 && GET_CODE (insn
) != JUMP_INSN
2238 && GET_CODE (PATTERN (insn
)) != USE
2239 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
2245 insn
= NEXT_INSN (insn
);
2251 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
2252 block. If so, we'll try to convert the insns to not require the branch.
2253 Return TRUE if we were successful at converting the block. */
2256 find_if_block (ce_info
)
2257 struct ce_if_block
* ce_info
;
2259 basic_block test_bb
= ce_info
->test_bb
;
2260 basic_block then_bb
= ce_info
->then_bb
;
2261 basic_block else_bb
= ce_info
->else_bb
;
2262 basic_block join_bb
= NULL_BLOCK
;
2263 edge then_succ
= then_bb
->succ
;
2264 edge else_succ
= else_bb
->succ
;
2265 int then_predecessors
;
2266 int else_predecessors
;
2270 ce_info
->last_test_bb
= test_bb
;
2272 /* Discover if any fall through predecessors of the current test basic block
2273 were && tests (which jump to the else block) or || tests (which jump to
2275 if (HAVE_conditional_execution
&& reload_completed
2276 && test_bb
->pred
!= NULL_EDGE
2277 && test_bb
->pred
->pred_next
== NULL_EDGE
2278 && test_bb
->pred
->flags
== EDGE_FALLTHRU
)
2280 basic_block bb
= test_bb
->pred
->src
;
2281 basic_block target_bb
;
2282 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
2285 /* Determine if the preceding block is an && or || block. */
2286 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
2288 ce_info
->and_and_p
= TRUE
;
2289 target_bb
= else_bb
;
2291 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
2293 ce_info
->and_and_p
= FALSE
;
2294 target_bb
= then_bb
;
2297 target_bb
= NULL_BLOCK
;
2299 if (target_bb
&& n_insns
<= max_insns
)
2301 int total_insns
= 0;
2304 ce_info
->last_test_bb
= test_bb
;
2306 /* Found at least one && or || block, look for more. */
2309 ce_info
->test_bb
= test_bb
= bb
;
2310 total_insns
+= n_insns
;
2313 if (bb
->pred
== NULL_EDGE
|| bb
->pred
->pred_next
!= NULL_EDGE
)
2317 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
2319 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
2321 ce_info
->num_multiple_test_blocks
= blocks
;
2322 ce_info
->num_multiple_test_insns
= total_insns
;
2324 if (ce_info
->and_and_p
)
2325 ce_info
->num_and_and_blocks
= blocks
;
2327 ce_info
->num_or_or_blocks
= blocks
;
2331 /* Count the number of edges the THEN and ELSE blocks have. */
2332 then_predecessors
= 0;
2333 for (cur_edge
= then_bb
->pred
;
2334 cur_edge
!= NULL_EDGE
;
2335 cur_edge
= cur_edge
->pred_next
)
2337 then_predecessors
++;
2338 if (cur_edge
->flags
& EDGE_COMPLEX
)
2342 else_predecessors
= 0;
2343 for (cur_edge
= else_bb
->pred
;
2344 cur_edge
!= NULL_EDGE
;
2345 cur_edge
= cur_edge
->pred_next
)
2347 else_predecessors
++;
2348 if (cur_edge
->flags
& EDGE_COMPLEX
)
2352 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
2353 other than any || blocks which jump to the THEN block. */
2354 if ((then_predecessors
- ce_info
->num_or_or_blocks
) != 1)
2357 /* The THEN block of an IF-THEN combo must have zero or one successors. */
2358 if (then_succ
!= NULL_EDGE
2359 && (then_succ
->succ_next
!= NULL_EDGE
2360 || (then_succ
->flags
& EDGE_COMPLEX
)))
2363 /* If the THEN block has no successors, conditional execution can still
2364 make a conditional call. Don't do this unless the ELSE block has
2365 only one incoming edge -- the CFG manipulation is too ugly otherwise.
2366 Check for the last insn of the THEN block being an indirect jump, which
2367 is listed as not having any successors, but confuses the rest of the CE
2368 code processing. ??? we should fix this in the future. */
2369 if (then_succ
== NULL
)
2371 if (else_bb
->pred
->pred_next
== NULL_EDGE
)
2373 rtx last_insn
= then_bb
->end
;
2376 && GET_CODE (last_insn
) == NOTE
2377 && last_insn
!= then_bb
->head
)
2378 last_insn
= PREV_INSN (last_insn
);
2381 && GET_CODE (last_insn
) == JUMP_INSN
2382 && ! simplejump_p (last_insn
))
2386 else_bb
= NULL_BLOCK
;
2392 /* If the THEN block's successor is the other edge out of the TEST block,
2393 then we have an IF-THEN combo without an ELSE. */
2394 else if (then_succ
->dest
== else_bb
)
2397 else_bb
= NULL_BLOCK
;
2400 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
2401 has exactly one predecessor and one successor, and the outgoing edge
2402 is not complex, then we have an IF-THEN-ELSE combo. */
2403 else if (else_succ
!= NULL_EDGE
2404 && then_succ
->dest
== else_succ
->dest
2405 && else_bb
->pred
->pred_next
== NULL_EDGE
2406 && else_succ
->succ_next
== NULL_EDGE
2407 && ! (else_succ
->flags
& EDGE_COMPLEX
))
2408 join_bb
= else_succ
->dest
;
2410 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
2414 num_possible_if_blocks
++;
2418 fprintf (rtl_dump_file
, "\nIF-THEN%s block found, pass %d, start block %d [insn %d], then %d [%d]",
2419 (else_bb
) ? "-ELSE" : "",
2421 test_bb
->index
, (test_bb
->head
) ? (int)INSN_UID (test_bb
->head
) : -1,
2422 then_bb
->index
, (then_bb
->head
) ? (int)INSN_UID (then_bb
->head
) : -1);
2425 fprintf (rtl_dump_file
, ", else %d [%d]",
2426 else_bb
->index
, (else_bb
->head
) ? (int)INSN_UID (else_bb
->head
) : -1);
2428 fprintf (rtl_dump_file
, ", join %d [%d]",
2429 join_bb
->index
, (join_bb
->head
) ? (int)INSN_UID (join_bb
->head
) : -1);
2431 if (ce_info
->num_multiple_test_blocks
> 0)
2432 fprintf (rtl_dump_file
, ", %d %s block%s last test %d [%d]",
2433 ce_info
->num_multiple_test_blocks
,
2434 (ce_info
->and_and_p
) ? "&&" : "||",
2435 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
2436 ce_info
->last_test_bb
->index
,
2437 ((ce_info
->last_test_bb
->head
)
2438 ? (int)INSN_UID (ce_info
->last_test_bb
->head
)
2441 fputc ('\n', rtl_dump_file
);
2444 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
2445 first condition for free, since we've already asserted that there's a
2446 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
2447 we checked the FALLTHRU flag, those are already adjacent to the last IF
2449 /* ??? As an enhancement, move the ELSE block. Have to deal with
2450 BLOCK notes, if by no other means than aborting the merge if they
2451 exist. Sticky enough I don't want to think about it now. */
2453 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
2455 if ((next
= next
->next_bb
) != join_bb
&& join_bb
!= EXIT_BLOCK_PTR
)
2463 /* Do the real work. */
2464 ce_info
->else_bb
= else_bb
;
2465 ce_info
->join_bb
= join_bb
;
2467 return process_if_block (ce_info
);
2470 /* Convert a branch over a trap, or a branch
2471 to a trap, into a conditional trap. */
2474 find_cond_trap (test_bb
, then_edge
, else_edge
)
2475 basic_block test_bb
;
2476 edge then_edge
, else_edge
;
2478 basic_block then_bb
= then_edge
->dest
;
2479 basic_block else_bb
= else_edge
->dest
;
2480 basic_block other_bb
, trap_bb
;
2481 rtx trap
, jump
, cond
, cond_earliest
, seq
;
2484 /* Locate the block with the trap instruction. */
2485 /* ??? While we look for no successors, we really ought to allow
2486 EH successors. Need to fix merge_if_block for that to work. */
2487 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
2488 trap_bb
= then_bb
, other_bb
= else_bb
;
2489 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
2490 trap_bb
= else_bb
, other_bb
= then_bb
;
2496 fprintf (rtl_dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
2497 test_bb
->index
, trap_bb
->index
);
2500 /* If this is not a standard conditional jump, we can't parse it. */
2501 jump
= test_bb
->end
;
2502 cond
= noce_get_condition (jump
, &cond_earliest
);
2506 /* If the conditional jump is more than just a conditional jump, then
2507 we can not do if-conversion on this block. */
2508 if (! onlyjump_p (jump
))
2511 /* We must be comparing objects whose modes imply the size. */
2512 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
2515 /* Reverse the comparison code, if necessary. */
2516 code
= GET_CODE (cond
);
2517 if (then_bb
== trap_bb
)
2519 code
= reversed_comparison_code (cond
, jump
);
2520 if (code
== UNKNOWN
)
2524 /* Attempt to generate the conditional trap. */
2525 seq
= gen_cond_trap (code
, XEXP (cond
, 0), XEXP (cond
, 1),
2526 TRAP_CODE (PATTERN (trap
)));
2530 /* Emit the new insns before cond_earliest. */
2531 emit_insn_before_scope (seq
, cond_earliest
, INSN_SCOPE (trap
));
2533 /* Delete the trap block if possible. */
2534 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
2535 if (trap_bb
->pred
== NULL
)
2537 if (post_dominators
)
2538 delete_from_dominance_info (post_dominators
, trap_bb
);
2539 flow_delete_block (trap_bb
);
2540 num_removed_blocks
++;
2543 /* If the non-trap block and the test are now adjacent, merge them.
2544 Otherwise we must insert a direct branch. */
2545 if (test_bb
->next_bb
== other_bb
)
2547 struct ce_if_block new_ce_info
;
2549 memset ((PTR
) &new_ce_info
, '\0', sizeof (new_ce_info
));
2550 new_ce_info
.test_bb
= test_bb
;
2551 new_ce_info
.then_bb
= NULL
;
2552 new_ce_info
.else_bb
= NULL
;
2553 new_ce_info
.join_bb
= other_bb
;
2554 merge_if_block (&new_ce_info
);
2560 lab
= JUMP_LABEL (jump
);
2561 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
2562 LABEL_NUSES (lab
) += 1;
2563 JUMP_LABEL (newjump
) = lab
;
2564 emit_barrier_after (newjump
);
2572 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
2576 block_has_only_trap (bb
)
2581 /* We're not the exit block. */
2582 if (bb
== EXIT_BLOCK_PTR
)
2585 /* The block must have no successors. */
2589 /* The only instruction in the THEN block must be the trap. */
2590 trap
= first_active_insn (bb
);
2591 if (! (trap
== bb
->end
2592 && GET_CODE (PATTERN (trap
)) == TRAP_IF
2593 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
2599 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
2600 transformable, but not necessarily the other. There need be no
2603 Return TRUE if we were successful at converting the block.
2605 Cases we'd like to look at:
2608 if (test) goto over; // x not live
2616 if (! test) goto label;
2619 if (test) goto E; // x not live
2633 (3) // This one's really only interesting for targets that can do
2634 // multiway branching, e.g. IA-64 BBB bundles. For other targets
2635 // it results in multiple branches on a cache line, which often
2636 // does not sit well with predictors.
2638 if (test1) goto E; // predicted not taken
2654 (A) Don't do (2) if the branch is predicted against the block we're
2655 eliminating. Do it anyway if we can eliminate a branch; this requires
2656 that the sole successor of the eliminated block postdominate the other
2659 (B) With CE, on (3) we can steal from both sides of the if, creating
2668 Again, this is most useful if J postdominates.
2670 (C) CE substitutes for helpful life information.
2672 (D) These heuristics need a lot of work. */
2674 /* Tests for case 1 above. */
2677 find_if_case_1 (test_bb
, then_edge
, else_edge
)
2678 basic_block test_bb
;
2679 edge then_edge
, else_edge
;
2681 basic_block then_bb
= then_edge
->dest
;
2682 basic_block else_bb
= else_edge
->dest
, new_bb
;
2683 edge then_succ
= then_bb
->succ
;
2686 /* THEN has one successor. */
2687 if (!then_succ
|| then_succ
->succ_next
!= NULL
)
2690 /* THEN does not fall through, but is not strange either. */
2691 if (then_succ
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
2694 /* THEN has one predecessor. */
2695 if (then_bb
->pred
->pred_next
!= NULL
)
2698 /* THEN must do something. */
2699 if (forwarder_block_p (then_bb
))
2702 num_possible_if_blocks
++;
2704 fprintf (rtl_dump_file
,
2705 "\nIF-CASE-1 found, start %d, then %d\n",
2706 test_bb
->index
, then_bb
->index
);
2708 /* THEN is small. */
2709 if (count_bb_insns (then_bb
) > BRANCH_COST
)
2712 /* Registers set are dead, or are predicable. */
2713 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
2714 then_bb
->succ
->dest
, 1))
2717 /* Conversion went ok, including moving the insns and fixing up the
2718 jump. Adjust the CFG to match. */
2720 bitmap_operation (test_bb
->global_live_at_end
,
2721 else_bb
->global_live_at_start
,
2722 then_bb
->global_live_at_end
, BITMAP_IOR
);
2724 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
), else_bb
);
2725 then_bb_index
= then_bb
->index
;
2726 if (post_dominators
)
2727 delete_from_dominance_info (post_dominators
, then_bb
);
2728 flow_delete_block (then_bb
);
2730 /* Make rest of code believe that the newly created block is the THEN_BB
2731 block we removed. */
2734 new_bb
->index
= then_bb_index
;
2735 BASIC_BLOCK (then_bb_index
) = new_bb
;
2737 /* We've possibly created jump to next insn, cleanup_cfg will solve that
2740 num_removed_blocks
++;
2741 num_updated_if_blocks
++;
2746 /* Test for case 2 above. */
2749 find_if_case_2 (test_bb
, then_edge
, else_edge
)
2750 basic_block test_bb
;
2751 edge then_edge
, else_edge
;
2753 basic_block then_bb
= then_edge
->dest
;
2754 basic_block else_bb
= else_edge
->dest
;
2755 edge else_succ
= else_bb
->succ
;
2758 /* ELSE has one successor. */
2759 if (!else_succ
|| else_succ
->succ_next
!= NULL
)
2762 /* ELSE outgoing edge is not complex. */
2763 if (else_succ
->flags
& EDGE_COMPLEX
)
2766 /* ELSE has one predecessor. */
2767 if (else_bb
->pred
->pred_next
!= NULL
)
2770 /* THEN is not EXIT. */
2771 if (then_bb
->index
< 0)
2774 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
2775 note
= find_reg_note (test_bb
->end
, REG_BR_PROB
, NULL_RTX
);
2776 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
2778 else if (else_succ
->dest
->index
< 0
2779 || dominated_by_p (post_dominators
, then_bb
,
2785 num_possible_if_blocks
++;
2787 fprintf (rtl_dump_file
,
2788 "\nIF-CASE-2 found, start %d, else %d\n",
2789 test_bb
->index
, else_bb
->index
);
2791 /* ELSE is small. */
2792 if (count_bb_insns (else_bb
) > BRANCH_COST
)
2795 /* Registers set are dead, or are predicable. */
2796 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
2799 /* Conversion went ok, including moving the insns and fixing up the
2800 jump. Adjust the CFG to match. */
2802 bitmap_operation (test_bb
->global_live_at_end
,
2803 then_bb
->global_live_at_start
,
2804 else_bb
->global_live_at_end
, BITMAP_IOR
);
2806 if (post_dominators
)
2807 delete_from_dominance_info (post_dominators
, else_bb
);
2808 flow_delete_block (else_bb
);
2810 num_removed_blocks
++;
2811 num_updated_if_blocks
++;
2813 /* ??? We may now fallthru from one of THEN's successors into a join
2814 block. Rerun cleanup_cfg? Examine things manually? Wait? */
2819 /* A subroutine of dead_or_predicable called through for_each_rtx.
2820 Return 1 if a memory is found. */
2823 find_memory (px
, data
)
2825 void *data ATTRIBUTE_UNUSED
;
2827 return GET_CODE (*px
) == MEM
;
2830 /* Used by the code above to perform the actual rtl transformations.
2831 Return TRUE if successful.
2833 TEST_BB is the block containing the conditional branch. MERGE_BB
2834 is the block containing the code to manipulate. NEW_DEST is the
2835 label TEST_BB should be branching to after the conversion.
2836 REVERSEP is true if the sense of the branch should be reversed. */
2839 dead_or_predicable (test_bb
, merge_bb
, other_bb
, new_dest
, reversep
)
2840 basic_block test_bb
, merge_bb
, other_bb
;
2841 basic_block new_dest
;
2844 rtx head
, end
, jump
, earliest
, old_dest
, new_label
= NULL_RTX
;
2846 jump
= test_bb
->end
;
2848 /* Find the extent of the real code in the merge block. */
2849 head
= merge_bb
->head
;
2850 end
= merge_bb
->end
;
2852 if (GET_CODE (head
) == CODE_LABEL
)
2853 head
= NEXT_INSN (head
);
2854 if (GET_CODE (head
) == NOTE
)
2858 head
= end
= NULL_RTX
;
2861 head
= NEXT_INSN (head
);
2864 if (GET_CODE (end
) == JUMP_INSN
)
2868 head
= end
= NULL_RTX
;
2871 end
= PREV_INSN (end
);
2874 /* Disable handling dead code by conditional execution if the machine needs
2875 to do anything funny with the tests, etc. */
2876 #ifndef IFCVT_MODIFY_TESTS
2877 if (HAVE_conditional_execution
)
2879 /* In the conditional execution case, we have things easy. We know
2880 the condition is reversible. We don't have to check life info,
2881 becase we're going to conditionally execute the code anyway.
2882 All that's left is making sure the insns involved can actually
2887 cond
= cond_exec_get_condition (jump
);
2891 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
2893 prob_val
= XEXP (prob_val
, 0);
2897 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
2900 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
2903 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
2906 if (! cond_exec_process_insns ((ce_if_block_t
*)0, head
, end
, cond
,
2915 /* In the non-conditional execution case, we have to verify that there
2916 are no trapping operations, no calls, no references to memory, and
2917 that any registers modified are dead at the branch site. */
2919 rtx insn
, cond
, prev
;
2920 regset_head merge_set_head
, tmp_head
, test_live_head
, test_set_head
;
2921 regset merge_set
, tmp
, test_live
, test_set
;
2922 struct propagate_block_info
*pbi
;
2925 /* Check for no calls or trapping operations. */
2926 for (insn
= head
; ; insn
= NEXT_INSN (insn
))
2928 if (GET_CODE (insn
) == CALL_INSN
)
2932 if (may_trap_p (PATTERN (insn
)))
2935 /* ??? Even non-trapping memories such as stack frame
2936 references must be avoided. For stores, we collect
2937 no lifetime info; for reads, we'd have to assert
2938 true_dependence false against every store in the
2940 if (for_each_rtx (&PATTERN (insn
), find_memory
, NULL
))
2947 if (! any_condjump_p (jump
))
2950 /* Find the extent of the conditional. */
2951 cond
= noce_get_condition (jump
, &earliest
);
2956 MERGE_SET = set of registers set in MERGE_BB
2957 TEST_LIVE = set of registers live at EARLIEST
2958 TEST_SET = set of registers set between EARLIEST and the
2959 end of the block. */
2961 tmp
= INITIALIZE_REG_SET (tmp_head
);
2962 merge_set
= INITIALIZE_REG_SET (merge_set_head
);
2963 test_live
= INITIALIZE_REG_SET (test_live_head
);
2964 test_set
= INITIALIZE_REG_SET (test_set_head
);
2966 /* ??? bb->local_set is only valid during calculate_global_regs_live,
2967 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
2968 since we've already asserted that MERGE_BB is small. */
2969 propagate_block (merge_bb
, tmp
, merge_set
, merge_set
, 0);
2971 /* For small register class machines, don't lengthen lifetimes of
2972 hard registers before reload. */
2973 if (SMALL_REGISTER_CLASSES
&& ! reload_completed
)
2975 EXECUTE_IF_SET_IN_BITMAP
2978 if (i
< FIRST_PSEUDO_REGISTER
2980 && ! global_regs
[i
])
2985 /* For TEST, we're interested in a range of insns, not a whole block.
2986 Moreover, we're interested in the insns live from OTHER_BB. */
2988 COPY_REG_SET (test_live
, other_bb
->global_live_at_start
);
2989 pbi
= init_propagate_block_info (test_bb
, test_live
, test_set
, test_set
,
2992 for (insn
= jump
; ; insn
= prev
)
2994 prev
= propagate_one_insn (pbi
, insn
);
2995 if (insn
== earliest
)
2999 free_propagate_block_info (pbi
);
3001 /* We can perform the transformation if
3002 MERGE_SET & (TEST_SET | TEST_LIVE)
3004 TEST_SET & merge_bb->global_live_at_start
3007 bitmap_operation (tmp
, test_set
, test_live
, BITMAP_IOR
);
3008 bitmap_operation (tmp
, tmp
, merge_set
, BITMAP_AND
);
3009 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
3011 bitmap_operation (tmp
, test_set
, merge_bb
->global_live_at_start
,
3013 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
3016 FREE_REG_SET (merge_set
);
3017 FREE_REG_SET (test_live
);
3018 FREE_REG_SET (test_set
);
3025 /* We don't want to use normal invert_jump or redirect_jump because
3026 we don't want to delete_insn called. Also, we want to do our own
3027 change group management. */
3029 old_dest
= JUMP_LABEL (jump
);
3030 if (other_bb
!= new_dest
)
3032 new_label
= block_label (new_dest
);
3034 ? ! invert_jump_1 (jump
, new_label
)
3035 : ! redirect_jump_1 (jump
, new_label
))
3039 if (! apply_change_group ())
3042 if (other_bb
!= new_dest
)
3045 LABEL_NUSES (old_dest
) -= 1;
3047 LABEL_NUSES (new_label
) += 1;
3048 JUMP_LABEL (jump
) = new_label
;
3050 invert_br_probabilities (jump
);
3052 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
3055 gcov_type count
, probability
;
3056 count
= BRANCH_EDGE (test_bb
)->count
;
3057 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
3058 FALLTHRU_EDGE (test_bb
)->count
= count
;
3059 probability
= BRANCH_EDGE (test_bb
)->probability
;
3060 BRANCH_EDGE (test_bb
)->probability
3061 = FALLTHRU_EDGE (test_bb
)->probability
;
3062 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
3063 update_br_prob_note (test_bb
);
3067 /* Move the insns out of MERGE_BB to before the branch. */
3070 if (end
== merge_bb
->end
)
3071 merge_bb
->end
= PREV_INSN (head
);
3073 if (squeeze_notes (&head
, &end
))
3076 reorder_insns (head
, end
, PREV_INSN (earliest
));
3079 /* Remove the jump and edge if we can. */
3080 if (other_bb
== new_dest
)
3083 remove_edge (BRANCH_EDGE (test_bb
));
3084 /* ??? Can't merge blocks here, as then_bb is still in use.
3085 At minimum, the merge will get done just before bb-reorder. */
3095 /* Main entry point for all if-conversion. */
3098 if_convert (x_life_data_ok
)
3104 num_possible_if_blocks
= 0;
3105 num_updated_if_blocks
= 0;
3106 num_removed_blocks
= 0;
3107 life_data_ok
= (x_life_data_ok
!= 0);
3109 /* Free up basic_block_for_insn so that we don't have to keep it
3110 up to date, either here or in merge_blocks_nomove. */
3111 free_basic_block_vars (1);
3113 /* Compute postdominators if we think we'll use them. */
3114 post_dominators
= NULL
;
3115 if (HAVE_conditional_execution
|| life_data_ok
)
3117 post_dominators
= calculate_dominance_info (CDI_POST_DOMINATORS
);
3122 /* Go through each of the basic blocks looking for things to convert. If we
3123 have conditional execution, we make multiple passes to allow us to handle
3124 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
3128 cond_exec_changed_p
= FALSE
;
3131 #ifdef IFCVT_MULTIPLE_DUMPS
3132 if (rtl_dump_file
&& pass
> 1)
3133 fprintf (rtl_dump_file
, "\n\n========== Pass %d ==========\n", pass
);
3139 while ((new_bb
= find_if_header (bb
, pass
)))
3143 #ifdef IFCVT_MULTIPLE_DUMPS
3144 if (rtl_dump_file
&& cond_exec_changed_p
)
3145 print_rtl_with_bb (rtl_dump_file
, get_insns ());
3148 while (cond_exec_changed_p
);
3150 #ifdef IFCVT_MULTIPLE_DUMPS
3152 fprintf (rtl_dump_file
, "\n\n========== no more changes\n");
3155 if (post_dominators
)
3156 free_dominance_info (post_dominators
);
3159 fflush (rtl_dump_file
);
3161 clear_aux_for_blocks ();
3163 /* Rebuild life info for basic blocks that require it. */
3164 if (num_removed_blocks
&& life_data_ok
)
3166 /* If we allocated new pseudos, we must resize the array for sched1. */
3167 if (max_regno
< max_reg_num ())
3169 max_regno
= max_reg_num ();
3170 allocate_reg_info (max_regno
, FALSE
, FALSE
);
3172 update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES
,
3173 PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
3174 | PROP_KILL_DEAD_CODE
);
3177 /* Write the final stats. */
3178 if (rtl_dump_file
&& num_possible_if_blocks
> 0)
3180 fprintf (rtl_dump_file
,
3181 "\n%d possible IF blocks searched.\n",
3182 num_possible_if_blocks
);
3183 fprintf (rtl_dump_file
,
3184 "%d IF blocks converted.\n",
3185 num_updated_if_blocks
);
3186 fprintf (rtl_dump_file
,
3187 "%d basic blocks deleted.\n\n\n",
3188 num_removed_blocks
);
3191 #ifdef ENABLE_CHECKING
3192 verify_flow_info ();