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
28 #include "insn-config.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
39 #ifndef HAVE_conditional_execution
40 #define HAVE_conditional_execution 0
42 #ifndef HAVE_conditional_move
43 #define HAVE_conditional_move 0
54 #ifndef HAVE_conditional_trap
55 #define HAVE_conditional_trap 0
58 #ifndef MAX_CONDITIONAL_EXECUTE
59 #define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1)
62 #define NULL_EDGE ((struct edge_def *)NULL)
63 #define NULL_BLOCK ((struct basic_block_def *)NULL)
65 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
66 static int num_possible_if_blocks
;
68 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
70 static int num_updated_if_blocks
;
72 /* # of basic blocks that were removed. */
73 static int num_removed_blocks
;
75 /* True if life data ok at present. */
76 static bool life_data_ok
;
78 /* The post-dominator relation on the original block numbers. */
79 static sbitmap
*post_dominators
;
81 /* Forward references. */
82 static int count_bb_insns
PARAMS ((basic_block
));
83 static rtx first_active_insn
PARAMS ((basic_block
));
84 static int last_active_insn_p
PARAMS ((basic_block
, rtx
));
85 static int seq_contains_jump
PARAMS ((rtx
));
87 static int cond_exec_process_insns
PARAMS ((rtx
, rtx
, rtx
, rtx
, int));
88 static rtx cond_exec_get_condition
PARAMS ((rtx
));
89 static int cond_exec_process_if_block
PARAMS ((basic_block
, basic_block
,
90 basic_block
, basic_block
));
92 static rtx noce_get_condition
PARAMS ((rtx
, rtx
*));
93 static int noce_operand_ok
PARAMS ((rtx
));
94 static int noce_process_if_block
PARAMS ((basic_block
, basic_block
,
95 basic_block
, basic_block
));
97 static int process_if_block
PARAMS ((basic_block
, basic_block
,
98 basic_block
, basic_block
));
99 static void merge_if_block
PARAMS ((basic_block
, basic_block
,
100 basic_block
, basic_block
));
102 static int find_if_header
PARAMS ((basic_block
));
103 static int find_if_block
PARAMS ((basic_block
, edge
, edge
));
104 static int find_if_case_1
PARAMS ((basic_block
, edge
, edge
));
105 static int find_if_case_2
PARAMS ((basic_block
, edge
, edge
));
106 static int find_cond_trap
PARAMS ((basic_block
, edge
, edge
));
107 static int find_memory
PARAMS ((rtx
*, void *));
108 static int dead_or_predicable
PARAMS ((basic_block
, basic_block
,
109 basic_block
, basic_block
, int));
110 static void noce_emit_move_insn
PARAMS ((rtx
, rtx
));
112 /* Abuse the basic_block AUX field to store the original block index,
113 as well as a flag indicating that the block should be rescaned for
116 #define SET_ORIG_INDEX(BB,I) ((BB)->aux = (void *)((size_t)(I)))
117 #define ORIG_INDEX(BB) ((size_t)(BB)->aux)
120 /* Count the number of non-jump active insns in BB. */
131 if (GET_CODE (insn
) == CALL_INSN
|| GET_CODE (insn
) == INSN
)
136 insn
= NEXT_INSN (insn
);
142 /* Return the first non-jump active insn in the basic block. */
145 first_active_insn (bb
)
150 if (GET_CODE (insn
) == CODE_LABEL
)
154 insn
= NEXT_INSN (insn
);
157 while (GET_CODE (insn
) == NOTE
)
161 insn
= NEXT_INSN (insn
);
164 if (GET_CODE (insn
) == JUMP_INSN
)
170 /* Return true if INSN is the last active non-jump insn in BB. */
173 last_active_insn_p (bb
, insn
)
181 insn
= NEXT_INSN (insn
);
183 while (GET_CODE (insn
) == NOTE
);
185 return GET_CODE (insn
) == JUMP_INSN
;
188 /* It is possible, especially when having dealt with multi-word
189 arithmetic, for the expanders to have emitted jumps. Search
190 through the sequence and return TRUE if a jump exists so that
191 we can abort the conversion. */
194 seq_contains_jump (insn
)
199 if (GET_CODE (insn
) == JUMP_INSN
)
201 insn
= NEXT_INSN (insn
);
206 /* Go through a bunch of insns, converting them to conditional
207 execution format if possible. Return TRUE if all of the non-note
208 insns were processed. */
211 cond_exec_process_insns (start
, end
, test
, prob_val
, mod_ok
)
212 rtx start
; /* first insn to look at */
213 rtx end
; /* last insn to look at */
214 rtx test
; /* conditional execution test */
215 rtx prob_val
; /* probability of branch taken. */
216 int mod_ok
; /* true if modifications ok last insn. */
218 int must_be_last
= FALSE
;
222 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
224 if (GET_CODE (insn
) == NOTE
)
227 if (GET_CODE (insn
) != INSN
&& GET_CODE (insn
) != CALL_INSN
)
230 /* Remove USE insns that get in the way. */
231 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
233 /* ??? Ug. Actually unlinking the thing is problematic,
234 given what we'd have to coordinate with our callers. */
235 PUT_CODE (insn
, NOTE
);
236 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
237 NOTE_SOURCE_FILE (insn
) = 0;
241 /* Last insn wasn't last? */
245 if (modified_in_p (test
, insn
))
252 /* Now build the conditional form of the instruction. */
253 pattern
= PATTERN (insn
);
255 /* If the machine needs to modify the insn being conditionally executed,
256 say for example to force a constant integer operand into a temp
257 register, do so here. */
258 #ifdef IFCVT_MODIFY_INSN
259 IFCVT_MODIFY_INSN (pattern
, insn
);
264 validate_change (insn
, &PATTERN (insn
),
265 gen_rtx_COND_EXEC (VOIDmode
, copy_rtx (test
),
268 if (GET_CODE (insn
) == CALL_INSN
&& prob_val
)
269 validate_change (insn
, ®_NOTES (insn
),
270 alloc_EXPR_LIST (REG_BR_PROB
, prob_val
,
271 REG_NOTES (insn
)), 1);
281 /* Return the condition for a jump. Do not do any special processing. */
284 cond_exec_get_condition (jump
)
289 if (any_condjump_p (jump
))
290 test_if
= SET_SRC (pc_set (jump
));
293 cond
= XEXP (test_if
, 0);
295 /* If this branches to JUMP_LABEL when the condition is false,
296 reverse the condition. */
297 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
298 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
300 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
304 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
311 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
312 to conditional execution. Return TRUE if we were successful at
313 converting the the block. */
316 cond_exec_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
317 basic_block test_bb
; /* Basic block test is in */
318 basic_block then_bb
; /* Basic block for THEN block */
319 basic_block else_bb
; /* Basic block for ELSE block */
320 basic_block join_bb
; /* Basic block the join label is in */
322 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
323 rtx then_start
; /* first insn in THEN block */
324 rtx then_end
; /* last insn + 1 in THEN block */
325 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
326 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
327 int max
; /* max # of insns to convert. */
328 int then_mod_ok
; /* whether conditional mods are ok in THEN */
329 rtx true_expr
; /* test for else block insns */
330 rtx false_expr
; /* test for then block insns */
331 rtx true_prob_val
; /* probability of else block */
332 rtx false_prob_val
; /* probability of then block */
334 enum rtx_code false_code
;
336 /* Find the conditional jump to the ELSE or JOIN part, and isolate
338 test_expr
= cond_exec_get_condition (test_bb
->end
);
342 /* If the conditional jump is more than just a conditional jump,
343 then we can not do conditional execution conversion on this block. */
344 if (!onlyjump_p (test_bb
->end
))
347 /* Collect the bounds of where we're to search. */
349 then_start
= then_bb
->head
;
350 then_end
= then_bb
->end
;
352 /* Skip a label heading THEN block. */
353 if (GET_CODE (then_start
) == CODE_LABEL
)
354 then_start
= NEXT_INSN (then_start
);
356 /* Skip a (use (const_int 0)) or branch as the final insn. */
357 if (GET_CODE (then_end
) == INSN
358 && GET_CODE (PATTERN (then_end
)) == USE
359 && GET_CODE (XEXP (PATTERN (then_end
), 0)) == CONST_INT
)
360 then_end
= PREV_INSN (then_end
);
361 else if (GET_CODE (then_end
) == JUMP_INSN
)
362 then_end
= PREV_INSN (then_end
);
366 /* Skip the ELSE block's label. */
367 else_start
= NEXT_INSN (else_bb
->head
);
368 else_end
= else_bb
->end
;
370 /* Skip a (use (const_int 0)) or branch as the final insn. */
371 if (GET_CODE (else_end
) == INSN
372 && GET_CODE (PATTERN (else_end
)) == USE
373 && GET_CODE (XEXP (PATTERN (else_end
), 0)) == CONST_INT
)
374 else_end
= PREV_INSN (else_end
);
375 else if (GET_CODE (else_end
) == JUMP_INSN
)
376 else_end
= PREV_INSN (else_end
);
379 /* How many instructions should we convert in total? */
383 max
= 2 * MAX_CONDITIONAL_EXECUTE
;
384 n_insns
= count_bb_insns (else_bb
);
387 max
= MAX_CONDITIONAL_EXECUTE
;
388 n_insns
+= count_bb_insns (then_bb
);
392 /* Map test_expr/test_jump into the appropriate MD tests to use on
393 the conditionally executed code. */
395 true_expr
= test_expr
;
397 false_code
= reversed_comparison_code (true_expr
, test_bb
->end
);
398 if (false_code
!= UNKNOWN
)
399 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
400 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
402 false_expr
= NULL_RTX
;
404 #ifdef IFCVT_MODIFY_TESTS
405 /* If the machine description needs to modify the tests, such as setting a
406 conditional execution register from a comparison, it can do so here. */
407 IFCVT_MODIFY_TESTS (true_expr
, false_expr
, test_bb
, then_bb
, else_bb
,
410 /* See if the conversion failed */
411 if (!true_expr
|| !false_expr
)
415 true_prob_val
= find_reg_note (test_bb
->end
, REG_BR_PROB
, NULL_RTX
);
418 true_prob_val
= XEXP (true_prob_val
, 0);
419 false_prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (true_prob_val
));
422 false_prob_val
= NULL_RTX
;
424 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
425 on then THEN block. */
426 then_mod_ok
= (else_bb
== NULL_BLOCK
);
428 /* Go through the THEN and ELSE blocks converting the insns if possible
429 to conditional execution. */
433 || ! cond_exec_process_insns (then_start
, then_end
, false_expr
,
434 false_prob_val
, then_mod_ok
)))
438 && ! cond_exec_process_insns (else_start
, else_end
,
439 true_expr
, true_prob_val
, TRUE
))
442 if (! apply_change_group ())
445 #ifdef IFCVT_MODIFY_FINAL
446 /* Do any machine dependent final modifications */
447 IFCVT_MODIFY_FINAL (test_bb
, then_bb
, else_bb
, join_bb
);
450 /* Conversion succeeded. */
452 fprintf (rtl_dump_file
, "%d insn%s converted to conditional execution.\n",
453 n_insns
, (n_insns
== 1) ? " was" : "s were");
455 /* Merge the blocks! */
456 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
460 #ifdef IFCVT_MODIFY_CANCEL
461 /* Cancel any machine dependent changes. */
462 IFCVT_MODIFY_CANCEL (test_bb
, then_bb
, else_bb
, join_bb
);
469 /* Used by noce_process_if_block to communicate with its subroutines.
471 The subroutines know that A and B may be evaluated freely. They
472 know that X is a register. They should insert new instructions
473 before cond_earliest. */
480 rtx jump
, cond
, cond_earliest
;
483 static rtx noce_emit_store_flag
PARAMS ((struct noce_if_info
*,
485 static int noce_try_store_flag
PARAMS ((struct noce_if_info
*));
486 static int noce_try_store_flag_inc
PARAMS ((struct noce_if_info
*));
487 static int noce_try_store_flag_constants
PARAMS ((struct noce_if_info
*));
488 static int noce_try_store_flag_mask
PARAMS ((struct noce_if_info
*));
489 static rtx noce_emit_cmove
PARAMS ((struct noce_if_info
*,
490 rtx
, enum rtx_code
, rtx
,
492 static int noce_try_cmove
PARAMS ((struct noce_if_info
*));
493 static int noce_try_cmove_arith
PARAMS ((struct noce_if_info
*));
494 static rtx noce_get_alt_condition
PARAMS ((struct noce_if_info
*,
496 static int noce_try_minmax
PARAMS ((struct noce_if_info
*));
497 static int noce_try_abs
PARAMS ((struct noce_if_info
*));
499 /* Helper function for noce_try_store_flag*. */
502 noce_emit_store_flag (if_info
, x
, reversep
, normalize
)
503 struct noce_if_info
*if_info
;
505 int reversep
, normalize
;
507 rtx cond
= if_info
->cond
;
511 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
512 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
514 /* If earliest == jump, or when the condition is complex, try to
515 build the store_flag insn directly. */
518 cond
= XEXP (SET_SRC (pc_set (if_info
->jump
)), 0);
521 code
= reversed_comparison_code (cond
, if_info
->jump
);
523 code
= GET_CODE (cond
);
525 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
526 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
530 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
532 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
535 tmp
= emit_insn (tmp
);
537 if (recog_memoized (tmp
) >= 0)
543 if_info
->cond_earliest
= if_info
->jump
;
551 /* Don't even try if the comparison operands are weird. */
555 return emit_store_flag (x
, code
, XEXP (cond
, 0),
556 XEXP (cond
, 1), VOIDmode
,
557 (code
== LTU
|| code
== LEU
558 || code
== GEU
|| code
== GTU
), normalize
);
561 /* Emit instruction to move an rtx into STRICT_LOW_PART. */
563 noce_emit_move_insn (x
, y
)
566 enum machine_mode outmode
, inmode
;
570 if (GET_CODE (x
) != STRICT_LOW_PART
)
572 emit_move_insn (x
, y
);
577 inner
= XEXP (outer
, 0);
578 outmode
= GET_MODE (outer
);
579 inmode
= GET_MODE (inner
);
580 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
581 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
, outmode
, y
,
582 GET_MODE_BITSIZE (inmode
));
585 /* Convert "if (test) x = 1; else x = 0".
587 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
588 tried in noce_try_store_flag_constants after noce_try_cmove has had
589 a go at the conversion. */
592 noce_try_store_flag (if_info
)
593 struct noce_if_info
*if_info
;
598 if (GET_CODE (if_info
->b
) == CONST_INT
599 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
600 && if_info
->a
== const0_rtx
)
602 else if (if_info
->b
== const0_rtx
603 && GET_CODE (if_info
->a
) == CONST_INT
604 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
605 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
613 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
616 if (target
!= if_info
->x
)
617 noce_emit_move_insn (if_info
->x
, target
);
621 emit_insns_before (seq
, if_info
->cond_earliest
);
632 /* Convert "if (test) x = a; else x = b", for A and B constant. */
635 noce_try_store_flag_constants (if_info
)
636 struct noce_if_info
*if_info
;
640 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
641 int normalize
, can_reverse
;
642 enum machine_mode mode
;
645 && GET_CODE (if_info
->a
) == CONST_INT
646 && GET_CODE (if_info
->b
) == CONST_INT
)
648 mode
= GET_MODE (if_info
->x
);
649 ifalse
= INTVAL (if_info
->a
);
650 itrue
= INTVAL (if_info
->b
);
652 /* Make sure we can represent the difference between the two values. */
653 if ((itrue
- ifalse
> 0)
654 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
657 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
659 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
663 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
665 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
666 && (STORE_FLAG_VALUE
== 1
667 || BRANCH_COST
>= 2))
669 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
670 && (STORE_FLAG_VALUE
== 1 || BRANCH_COST
>= 2))
671 normalize
= 1, reversep
= 1;
673 && (STORE_FLAG_VALUE
== -1
674 || BRANCH_COST
>= 2))
676 else if (ifalse
== -1 && can_reverse
677 && (STORE_FLAG_VALUE
== -1 || BRANCH_COST
>= 2))
678 normalize
= -1, reversep
= 1;
679 else if ((BRANCH_COST
>= 2 && STORE_FLAG_VALUE
== -1)
687 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
688 diff
= trunc_int_for_mode (-diff
, mode
);
692 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
699 /* if (test) x = 3; else x = 4;
700 => x = 3 + (test == 0); */
701 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
703 target
= expand_simple_binop (mode
,
704 (diff
== STORE_FLAG_VALUE
706 GEN_INT (ifalse
), target
, if_info
->x
, 0,
710 /* if (test) x = 8; else x = 0;
711 => x = (test != 0) << 3; */
712 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
714 target
= expand_simple_binop (mode
, ASHIFT
,
715 target
, GEN_INT (tmp
), if_info
->x
, 0,
719 /* if (test) x = -1; else x = b;
720 => x = -(test != 0) | b; */
721 else if (itrue
== -1)
723 target
= expand_simple_binop (mode
, IOR
,
724 target
, GEN_INT (ifalse
), if_info
->x
, 0,
728 /* if (test) x = a; else x = b;
729 => x = (-(test != 0) & (b - a)) + a; */
732 target
= expand_simple_binop (mode
, AND
,
733 target
, GEN_INT (diff
), if_info
->x
, 0,
736 target
= expand_simple_binop (mode
, PLUS
,
737 target
, GEN_INT (ifalse
),
738 if_info
->x
, 0, OPTAB_WIDEN
);
747 if (target
!= if_info
->x
)
748 noce_emit_move_insn (if_info
->x
, target
);
753 if (seq_contains_jump (seq
))
756 emit_insns_before (seq
, if_info
->cond_earliest
);
764 /* Convert "if (test) foo++" into "foo += (test != 0)", and
765 similarly for "foo--". */
768 noce_try_store_flag_inc (if_info
)
769 struct noce_if_info
*if_info
;
772 int subtract
, normalize
;
778 /* Should be no `else' case to worry about. */
779 && if_info
->b
== if_info
->x
780 && GET_CODE (if_info
->a
) == PLUS
781 && (XEXP (if_info
->a
, 1) == const1_rtx
782 || XEXP (if_info
->a
, 1) == constm1_rtx
)
783 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->x
)
784 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
787 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
788 subtract
= 0, normalize
= 0;
789 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
790 subtract
= 1, normalize
= 0;
792 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
796 target
= noce_emit_store_flag (if_info
,
797 gen_reg_rtx (GET_MODE (if_info
->x
)),
801 target
= expand_simple_binop (GET_MODE (if_info
->x
),
802 subtract
? MINUS
: PLUS
,
803 if_info
->x
, target
, if_info
->x
,
807 if (target
!= if_info
->x
)
808 noce_emit_move_insn (if_info
->x
, target
);
813 if (seq_contains_jump (seq
))
816 emit_insns_before (seq
, if_info
->cond_earliest
);
827 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
830 noce_try_store_flag_mask (if_info
)
831 struct noce_if_info
*if_info
;
839 || STORE_FLAG_VALUE
== -1)
840 && ((if_info
->a
== const0_rtx
841 && rtx_equal_p (if_info
->b
, if_info
->x
))
842 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
845 && if_info
->b
== const0_rtx
846 && rtx_equal_p (if_info
->a
, if_info
->x
))))
849 target
= noce_emit_store_flag (if_info
,
850 gen_reg_rtx (GET_MODE (if_info
->x
)),
853 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
854 if_info
->x
, target
, if_info
->x
, 0,
859 if (target
!= if_info
->x
)
860 noce_emit_move_insn (if_info
->x
, target
);
865 if (seq_contains_jump (seq
))
868 emit_insns_before (seq
, if_info
->cond_earliest
);
879 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
882 noce_emit_cmove (if_info
, x
, code
, cmp_a
, cmp_b
, vfalse
, vtrue
)
883 struct noce_if_info
*if_info
;
884 rtx x
, cmp_a
, cmp_b
, vfalse
, vtrue
;
887 /* If earliest == jump, try to build the cmove insn directly.
888 This is helpful when combine has created some complex condition
889 (like for alpha's cmovlbs) that we can't hope to regenerate
890 through the normal interface. */
892 if (if_info
->cond_earliest
== if_info
->jump
)
896 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
897 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
898 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
901 tmp
= emit_insn (tmp
);
903 if (recog_memoized (tmp
) >= 0)
915 /* Don't even try if the comparison operands are weird. */
916 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
917 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
920 #if HAVE_conditional_move
921 return emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
922 vtrue
, vfalse
, GET_MODE (x
),
923 (code
== LTU
|| code
== GEU
924 || code
== LEU
|| code
== GTU
));
926 /* We'll never get here, as noce_process_if_block doesn't call the
927 functions involved. Ifdef code, however, should be discouraged
928 because it leads to typos in the code not selected. However,
929 emit_conditional_move won't exist either. */
934 /* Try only simple constants and registers here. More complex cases
935 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
936 has had a go at it. */
939 noce_try_cmove (if_info
)
940 struct noce_if_info
*if_info
;
945 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
946 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
950 code
= GET_CODE (if_info
->cond
);
951 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
952 XEXP (if_info
->cond
, 0),
953 XEXP (if_info
->cond
, 1),
954 if_info
->a
, if_info
->b
);
958 if (target
!= if_info
->x
)
959 noce_emit_move_insn (if_info
->x
, target
);
963 emit_insns_before (seq
, if_info
->cond_earliest
);
976 /* Try more complex cases involving conditional_move. */
979 noce_try_cmove_arith (if_info
)
980 struct noce_if_info
*if_info
;
990 /* A conditional move from two memory sources is equivalent to a
991 conditional on their addresses followed by a load. Don't do this
992 early because it'll screw alias analysis. Note that we've
993 already checked for no side effects. */
994 if (! no_new_pseudos
&& cse_not_expected
995 && GET_CODE (a
) == MEM
&& GET_CODE (b
) == MEM
1000 x
= gen_reg_rtx (Pmode
);
1004 /* ??? We could handle this if we knew that a load from A or B could
1005 not fault. This is also true if we've already loaded
1006 from the address along the path from ENTRY. */
1007 else if (may_trap_p (a
) || may_trap_p (b
))
1010 /* if (test) x = a + b; else x = c - d;
1017 code
= GET_CODE (if_info
->cond
);
1018 insn_a
= if_info
->insn_a
;
1019 insn_b
= if_info
->insn_b
;
1021 /* Possibly rearrange operands to make things come out more natural. */
1022 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1025 if (rtx_equal_p (b
, x
))
1027 else if (general_operand (b
, GET_MODE (b
)))
1032 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1033 tmp
= a
, a
= b
, b
= tmp
;
1034 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1040 /* If either operand is complex, load it into a register first.
1041 The best way to do this is to copy the original insn. In this
1042 way we preserve any clobbers etc that the insn may have had.
1043 This is of course not possible in the IS_MEM case. */
1044 if (! general_operand (a
, GET_MODE (a
)))
1049 goto end_seq_and_fail
;
1053 tmp
= gen_reg_rtx (GET_MODE (a
));
1054 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1057 goto end_seq_and_fail
;
1060 a
= gen_reg_rtx (GET_MODE (a
));
1061 tmp
= copy_rtx (insn_a
);
1062 set
= single_set (tmp
);
1064 tmp
= emit_insn (PATTERN (tmp
));
1066 if (recog_memoized (tmp
) < 0)
1067 goto end_seq_and_fail
;
1069 if (! general_operand (b
, GET_MODE (b
)))
1074 goto end_seq_and_fail
;
1078 tmp
= gen_reg_rtx (GET_MODE (b
));
1079 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, b
));
1082 goto end_seq_and_fail
;
1085 b
= gen_reg_rtx (GET_MODE (b
));
1086 tmp
= copy_rtx (insn_b
);
1087 set
= single_set (tmp
);
1089 tmp
= emit_insn (PATTERN (tmp
));
1091 if (recog_memoized (tmp
) < 0)
1092 goto end_seq_and_fail
;
1095 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1096 XEXP (if_info
->cond
, 1), a
, b
);
1099 goto end_seq_and_fail
;
1101 /* If we're handling a memory for above, emit the load now. */
1104 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1106 /* Copy over flags as appropriate. */
1107 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1108 MEM_VOLATILE_P (tmp
) = 1;
1109 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1110 MEM_IN_STRUCT_P (tmp
) = 1;
1111 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1112 MEM_SCALAR_P (tmp
) = 1;
1113 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1114 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1116 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1118 noce_emit_move_insn (if_info
->x
, tmp
);
1120 else if (target
!= x
)
1121 noce_emit_move_insn (x
, target
);
1125 emit_insns_before (tmp
, if_info
->cond_earliest
);
1133 /* For most cases, the simplified condition we found is the best
1134 choice, but this is not the case for the min/max/abs transforms.
1135 For these we wish to know that it is A or B in the condition. */
1138 noce_get_alt_condition (if_info
, target
, earliest
)
1139 struct noce_if_info
*if_info
;
1143 rtx cond
, set
, insn
;
1146 /* If target is already mentioned in the known condition, return it. */
1147 if (reg_mentioned_p (target
, if_info
->cond
))
1149 *earliest
= if_info
->cond_earliest
;
1150 return if_info
->cond
;
1153 set
= pc_set (if_info
->jump
);
1154 cond
= XEXP (SET_SRC (set
), 0);
1156 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1157 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1159 /* If we're looking for a constant, try to make the conditional
1160 have that constant in it. There are two reasons why it may
1161 not have the constant we want:
1163 1. GCC may have needed to put the constant in a register, because
1164 the target can't compare directly against that constant. For
1165 this case, we look for a SET immediately before the comparison
1166 that puts a constant in that register.
1168 2. GCC may have canonicalized the conditional, for example
1169 replacing "if x < 4" with "if x <= 3". We can undo that (or
1170 make equivalent types of changes) to get the constants we need
1171 if they're off by one in the right direction. */
1173 if (GET_CODE (target
) == CONST_INT
)
1175 enum rtx_code code
= GET_CODE (if_info
->cond
);
1176 rtx op_a
= XEXP (if_info
->cond
, 0);
1177 rtx op_b
= XEXP (if_info
->cond
, 1);
1180 /* First, look to see if we put a constant in a register. */
1181 prev_insn
= PREV_INSN (if_info
->cond_earliest
);
1183 && INSN_P (prev_insn
)
1184 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1186 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1188 src
= SET_SRC (PATTERN (prev_insn
));
1189 if (GET_CODE (src
) == CONST_INT
)
1191 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1193 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1196 if (GET_CODE (op_a
) == CONST_INT
)
1201 code
= swap_condition (code
);
1206 /* Now, look to see if we can get the right constant by
1207 adjusting the conditional. */
1208 if (GET_CODE (op_b
) == CONST_INT
)
1210 HOST_WIDE_INT desired_val
= INTVAL (target
);
1211 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1216 if (actual_val
== desired_val
+ 1)
1219 op_b
= GEN_INT (desired_val
);
1223 if (actual_val
== desired_val
- 1)
1226 op_b
= GEN_INT (desired_val
);
1230 if (actual_val
== desired_val
- 1)
1233 op_b
= GEN_INT (desired_val
);
1237 if (actual_val
== desired_val
+ 1)
1240 op_b
= GEN_INT (desired_val
);
1248 /* If we made any changes, generate a new conditional that is
1249 equivalent to what we started with, but has the right
1251 if (code
!= GET_CODE (if_info
->cond
)
1252 || op_a
!= XEXP (if_info
->cond
, 0)
1253 || op_b
!= XEXP (if_info
->cond
, 1))
1255 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1256 *earliest
= if_info
->cond_earliest
;
1261 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1263 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1266 /* We almost certainly searched back to a different place.
1267 Need to re-verify correct lifetimes. */
1269 /* X may not be mentioned in the range (cond_earliest, jump]. */
1270 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1271 if (INSN_P (insn
) && reg_mentioned_p (if_info
->x
, insn
))
1274 /* A and B may not be modified in the range [cond_earliest, jump). */
1275 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1277 && (modified_in_p (if_info
->a
, insn
)
1278 || modified_in_p (if_info
->b
, insn
)))
1284 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1287 noce_try_minmax (if_info
)
1288 struct noce_if_info
*if_info
;
1290 rtx cond
, earliest
, target
, seq
;
1291 enum rtx_code code
, op
;
1294 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1298 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1299 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1300 to get the target to tell us... */
1301 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1302 || HONOR_NANS (GET_MODE (if_info
->x
)))
1305 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1309 /* Verify the condition is of the form we expect, and canonicalize
1310 the comparison code. */
1311 code
= GET_CODE (cond
);
1312 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1314 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1317 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1319 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1321 code
= swap_condition (code
);
1326 /* Determine what sort of operation this is. Note that the code is for
1327 a taken branch, so the code->operation mapping appears backwards. */
1360 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1361 if_info
->a
, if_info
->b
,
1362 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1368 if (target
!= if_info
->x
)
1369 noce_emit_move_insn (if_info
->x
, target
);
1374 if (seq_contains_jump (seq
))
1377 emit_insns_before (seq
, earliest
);
1378 if_info
->cond
= cond
;
1379 if_info
->cond_earliest
= earliest
;
1384 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1387 noce_try_abs (if_info
)
1388 struct noce_if_info
*if_info
;
1390 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1393 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1397 /* Recognize A and B as constituting an ABS or NABS. */
1400 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1402 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1404 c
= a
; a
= b
; b
= c
;
1410 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1414 /* Verify the condition is of the form we expect. */
1415 if (rtx_equal_p (XEXP (cond
, 0), b
))
1417 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1422 /* Verify that C is zero. Search backward through the block for
1423 a REG_EQUAL note if necessary. */
1426 rtx insn
, note
= NULL
;
1427 for (insn
= earliest
;
1428 insn
!= if_info
->test_bb
->head
;
1429 insn
= PREV_INSN (insn
))
1431 && ((note
= find_reg_note (insn
, REG_EQUAL
, c
))
1432 || (note
= find_reg_note (insn
, REG_EQUIV
, c
))))
1438 if (GET_CODE (c
) == MEM
1439 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
1440 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
1441 c
= get_pool_constant (XEXP (c
, 0));
1443 /* Work around funny ideas get_condition has wrt canonicalization.
1444 Note that these rtx constants are known to be CONST_INT, and
1445 therefore imply integer comparisons. */
1446 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
1448 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
1450 else if (c
!= CONST0_RTX (GET_MODE (b
)))
1453 /* Determine what sort of operation this is. */
1454 switch (GET_CODE (cond
))
1473 target
= expand_simple_unop (GET_MODE (if_info
->x
), ABS
, b
, if_info
->x
, 0);
1475 /* ??? It's a quandry whether cmove would be better here, especially
1476 for integers. Perhaps combine will clean things up. */
1477 if (target
&& negate
)
1478 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
, if_info
->x
, 0);
1486 if (target
!= if_info
->x
)
1487 noce_emit_move_insn (if_info
->x
, target
);
1492 if (seq_contains_jump (seq
))
1495 emit_insns_before (seq
, earliest
);
1496 if_info
->cond
= cond
;
1497 if_info
->cond_earliest
= earliest
;
1502 /* Look for the condition for the jump first. We'd prefer to avoid
1503 get_condition if we can -- it tries to look back for the contents
1504 of an original compare. On targets that use normal integers for
1505 comparisons, e.g. alpha, this is wasteful. */
1508 noce_get_condition (jump
, earliest
)
1515 /* If the condition variable is a register and is MODE_INT, accept it.
1516 Otherwise, fall back on get_condition. */
1518 if (! any_condjump_p (jump
))
1521 set
= pc_set (jump
);
1523 cond
= XEXP (SET_SRC (set
), 0);
1524 if (GET_CODE (XEXP (cond
, 0)) == REG
1525 && GET_MODE_CLASS (GET_MODE (XEXP (cond
, 0))) == MODE_INT
)
1529 /* If this branches to JUMP_LABEL when the condition is false,
1530 reverse the condition. */
1531 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1532 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
))
1533 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
1534 GET_MODE (cond
), XEXP (cond
, 0),
1538 cond
= get_condition (jump
, earliest
);
1543 /* Return true if OP is ok for if-then-else processing. */
1546 noce_operand_ok (op
)
1549 /* We special-case memories, so handle any of them with
1550 no address side effects. */
1551 if (GET_CODE (op
) == MEM
)
1552 return ! side_effects_p (XEXP (op
, 0));
1554 if (side_effects_p (op
))
1557 return ! may_trap_p (op
);
1560 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
1561 without using conditional execution. Return TRUE if we were
1562 successful at converting the the block. */
1565 noce_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1566 basic_block test_bb
; /* Basic block test is in */
1567 basic_block then_bb
; /* Basic block for THEN block */
1568 basic_block else_bb
; /* Basic block for ELSE block */
1569 basic_block join_bb
; /* Basic block the join label is in */
1571 /* We're looking for patterns of the form
1573 (1) if (...) x = a; else x = b;
1574 (2) x = b; if (...) x = a;
1575 (3) if (...) x = a; // as if with an initial x = x.
1577 The later patterns require jumps to be more expensive.
1579 ??? For future expansion, look for multiple X in such patterns. */
1581 struct noce_if_info if_info
;
1584 rtx orig_x
, x
, a
, b
;
1585 rtx jump
, cond
, insn
;
1587 /* If this is not a standard conditional jump, we can't parse it. */
1588 jump
= test_bb
->end
;
1589 cond
= noce_get_condition (jump
, &if_info
.cond_earliest
);
1593 /* If the conditional jump is more than just a conditional jump,
1594 then we can not do if-conversion on this block. */
1595 if (! onlyjump_p (jump
))
1598 /* We must be comparing objects whose modes imply the size. */
1599 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
1602 /* Look for one of the potential sets. */
1603 insn_a
= first_active_insn (then_bb
);
1605 || ! last_active_insn_p (then_bb
, insn_a
)
1606 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
1609 x
= SET_DEST (set_a
);
1610 a
= SET_SRC (set_a
);
1612 /* Look for the other potential set. Make sure we've got equivalent
1614 /* ??? This is overconservative. Storing to two different mems is
1615 as easy as conditionally computing the address. Storing to a
1616 single mem merely requires a scratch memory to use as one of the
1617 destination addresses; often the memory immediately below the
1618 stack pointer is available for this. */
1622 insn_b
= first_active_insn (else_bb
);
1624 || ! last_active_insn_p (else_bb
, insn_b
)
1625 || (set_b
= single_set (insn_b
)) == NULL_RTX
1626 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
1631 insn_b
= prev_nonnote_insn (if_info
.cond_earliest
);
1633 || GET_CODE (insn_b
) != INSN
1634 || (set_b
= single_set (insn_b
)) == NULL_RTX
1635 || ! rtx_equal_p (x
, SET_DEST (set_b
))
1636 || reg_mentioned_p (x
, cond
)
1637 || reg_mentioned_p (x
, a
)
1638 || reg_mentioned_p (x
, SET_SRC (set_b
)))
1639 insn_b
= set_b
= NULL_RTX
;
1641 b
= (set_b
? SET_SRC (set_b
) : x
);
1643 /* X may not be mentioned in the range (cond_earliest, jump]. */
1644 for (insn
= jump
; insn
!= if_info
.cond_earliest
; insn
= PREV_INSN (insn
))
1645 if (INSN_P (insn
) && reg_mentioned_p (x
, insn
))
1648 /* A and B may not be modified in the range [cond_earliest, jump). */
1649 for (insn
= if_info
.cond_earliest
; insn
!= jump
; insn
= NEXT_INSN (insn
))
1651 && (modified_in_p (a
, insn
) || modified_in_p (b
, insn
)))
1654 /* Only operate on register destinations, and even then avoid extending
1655 the lifetime of hard registers on small register class machines. */
1657 if (GET_CODE (x
) != REG
1658 || (SMALL_REGISTER_CLASSES
1659 && REGNO (x
) < FIRST_PSEUDO_REGISTER
))
1663 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
1664 ? XEXP (x
, 0) : x
));
1667 /* Don't operate on sources that may trap or are volatile. */
1668 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
1671 /* Set up the info block for our subroutines. */
1672 if_info
.test_bb
= test_bb
;
1673 if_info
.cond
= cond
;
1674 if_info
.jump
= jump
;
1675 if_info
.insn_a
= insn_a
;
1676 if_info
.insn_b
= insn_b
;
1681 /* Try optimizations in some approximation of a useful order. */
1682 /* ??? Should first look to see if X is live incoming at all. If it
1683 isn't, we don't need anything but an unconditional set. */
1685 /* Look and see if A and B are really the same. Avoid creating silly
1686 cmove constructs that no one will fix up later. */
1687 if (rtx_equal_p (a
, b
))
1689 /* If we have an INSN_B, we don't have to create any new rtl. Just
1690 move the instruction that we already have. If we don't have an
1691 INSN_B, that means that A == X, and we've got a noop move. In
1692 that case don't do anything and let the code below delete INSN_A. */
1693 if (insn_b
&& else_bb
)
1697 if (else_bb
&& insn_b
== else_bb
->end
)
1698 else_bb
->end
= PREV_INSN (insn_b
);
1699 reorder_insns (insn_b
, insn_b
, PREV_INSN (if_info
.cond_earliest
));
1701 /* If there was a REG_EQUAL note, delete it since it may have been
1702 true due to this insn being after a jump. */
1703 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
1704 remove_note (insn_b
, note
);
1708 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
1709 x must be executed twice. */
1710 else if (insn_b
&& side_effects_p (orig_x
))
1717 if (noce_try_store_flag (&if_info
))
1719 if (noce_try_minmax (&if_info
))
1721 if (noce_try_abs (&if_info
))
1723 if (HAVE_conditional_move
1724 && noce_try_cmove (&if_info
))
1726 if (! HAVE_conditional_execution
)
1728 if (noce_try_store_flag_constants (&if_info
))
1730 if (noce_try_store_flag_inc (&if_info
))
1732 if (noce_try_store_flag_mask (&if_info
))
1734 if (HAVE_conditional_move
1735 && noce_try_cmove_arith (&if_info
))
1742 /* The original sets may now be killed. */
1743 delete_insn (insn_a
);
1745 /* Several special cases here: First, we may have reused insn_b above,
1746 in which case insn_b is now NULL. Second, we want to delete insn_b
1747 if it came from the ELSE block, because follows the now correct
1748 write that appears in the TEST block. However, if we got insn_b from
1749 the TEST block, it may in fact be loading data needed for the comparison.
1750 We'll let life_analysis remove the insn if it's really dead. */
1751 if (insn_b
&& else_bb
)
1752 delete_insn (insn_b
);
1754 /* The new insns will have been inserted before cond_earliest. We should
1755 be able to remove the jump with impunity, but the condition itself may
1756 have been modified by gcse to be shared across basic blocks. */
1759 /* If we used a temporary, fix it up now. */
1763 noce_emit_move_insn (copy_rtx (orig_x
), x
);
1764 insn_b
= gen_sequence ();
1767 emit_insn_after (insn_b
, test_bb
->end
);
1770 /* Merge the blocks! */
1771 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
1776 /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
1777 straight line code. Return true if successful. */
1780 process_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1781 basic_block test_bb
; /* Basic block test is in */
1782 basic_block then_bb
; /* Basic block for THEN block */
1783 basic_block else_bb
; /* Basic block for ELSE block */
1784 basic_block join_bb
; /* Basic block the join label is in */
1786 if (! reload_completed
1787 && noce_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
))
1790 if (HAVE_conditional_execution
1792 && cond_exec_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
))
1798 /* Merge the blocks and mark for local life update. */
1801 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1802 basic_block test_bb
; /* Basic block test is in */
1803 basic_block then_bb
; /* Basic block for THEN block */
1804 basic_block else_bb
; /* Basic block for ELSE block */
1805 basic_block join_bb
; /* Basic block the join label is in */
1807 basic_block combo_bb
;
1809 /* All block merging is done into the lower block numbers. */
1813 /* First merge TEST block into THEN block. This is a no-brainer since
1814 the THEN block did not have a code label to begin with. */
1816 if (combo_bb
->global_live_at_end
)
1817 COPY_REG_SET (combo_bb
->global_live_at_end
, then_bb
->global_live_at_end
);
1818 merge_blocks_nomove (combo_bb
, then_bb
);
1819 num_removed_blocks
++;
1821 /* The ELSE block, if it existed, had a label. That label count
1822 will almost always be zero, but odd things can happen when labels
1823 get their addresses taken. */
1826 merge_blocks_nomove (combo_bb
, else_bb
);
1827 num_removed_blocks
++;
1830 /* If there was no join block reported, that means it was not adjacent
1831 to the others, and so we cannot merge them. */
1835 /* The outgoing edge for the current COMBO block should already
1836 be correct. Verify this. */
1837 if (combo_bb
->succ
== NULL_EDGE
)
1840 /* There should still be a branch at the end of the THEN or ELSE
1841 blocks taking us to our final destination. */
1842 if (GET_CODE (combo_bb
->end
) != JUMP_INSN
)
1846 /* The JOIN block may have had quite a number of other predecessors too.
1847 Since we've already merged the TEST, THEN and ELSE blocks, we should
1848 have only one remaining edge from our if-then-else diamond. If there
1849 is more than one remaining edge, it must come from elsewhere. There
1850 may be zero incoming edges if the THEN block didn't actually join
1851 back up (as with a call to abort). */
1852 else if ((join_bb
->pred
== NULL
1853 || join_bb
->pred
->pred_next
== NULL
)
1854 && join_bb
!= EXIT_BLOCK_PTR
)
1856 /* We can merge the JOIN. */
1857 if (combo_bb
->global_live_at_end
)
1858 COPY_REG_SET (combo_bb
->global_live_at_end
,
1859 join_bb
->global_live_at_end
);
1860 merge_blocks_nomove (combo_bb
, join_bb
);
1861 num_removed_blocks
++;
1865 /* We cannot merge the JOIN. */
1867 /* The outgoing edge for the current COMBO block should already
1868 be correct. Verify this. */
1869 if (combo_bb
->succ
->succ_next
!= NULL_EDGE
1870 || combo_bb
->succ
->dest
!= join_bb
)
1873 /* Remove the jump and cruft from the end of the COMBO block. */
1874 if (join_bb
!= EXIT_BLOCK_PTR
)
1875 tidy_fallthru_edge (combo_bb
->succ
, combo_bb
, join_bb
);
1878 num_updated_if_blocks
++;
1881 /* Find a block ending in a simple IF condition. Return TRUE if
1882 we were able to transform it in some way. */
1885 find_if_header (test_bb
)
1886 basic_block test_bb
;
1891 /* The kind of block we're looking for has exactly two successors. */
1892 if ((then_edge
= test_bb
->succ
) == NULL_EDGE
1893 || (else_edge
= then_edge
->succ_next
) == NULL_EDGE
1894 || else_edge
->succ_next
!= NULL_EDGE
)
1897 /* Neither edge should be abnormal. */
1898 if ((then_edge
->flags
& EDGE_COMPLEX
)
1899 || (else_edge
->flags
& EDGE_COMPLEX
))
1902 /* The THEN edge is canonically the one that falls through. */
1903 if (then_edge
->flags
& EDGE_FALLTHRU
)
1905 else if (else_edge
->flags
& EDGE_FALLTHRU
)
1908 else_edge
= then_edge
;
1912 /* Otherwise this must be a multiway branch of some sort. */
1915 if (find_if_block (test_bb
, then_edge
, else_edge
))
1917 if (HAVE_trap
&& HAVE_conditional_trap
1918 && find_cond_trap (test_bb
, then_edge
, else_edge
))
1921 && (! HAVE_conditional_execution
|| reload_completed
))
1923 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
1925 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
1933 fprintf (rtl_dump_file
, "Conversion succeeded.\n");
1937 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
1938 block. If so, we'll try to convert the insns to not require the branch.
1939 Return TRUE if we were successful at converting the the block. */
1942 find_if_block (test_bb
, then_edge
, else_edge
)
1943 basic_block test_bb
;
1944 edge then_edge
, else_edge
;
1946 basic_block then_bb
= then_edge
->dest
;
1947 basic_block else_bb
= else_edge
->dest
;
1948 basic_block join_bb
= NULL_BLOCK
;
1949 edge then_succ
= then_bb
->succ
;
1950 edge else_succ
= else_bb
->succ
;
1953 /* The THEN block of an IF-THEN combo must have exactly one predecessor. */
1954 if (then_bb
->pred
->pred_next
!= NULL_EDGE
)
1957 /* The THEN block of an IF-THEN combo must have zero or one successors. */
1958 if (then_succ
!= NULL_EDGE
1959 && (then_succ
->succ_next
!= NULL_EDGE
1960 || (then_succ
->flags
& EDGE_COMPLEX
)))
1963 /* If the THEN block has no successors, conditional execution can still
1964 make a conditional call. Don't do this unless the ELSE block has
1965 only one incoming edge -- the CFG manipulation is too ugly otherwise.
1966 Check for the last insn of the THEN block being an indirect jump, which
1967 is listed as not having any successors, but confuses the rest of the CE
1968 code processing. XXX we should fix this in the future. */
1969 if (then_succ
== NULL
)
1971 if (else_bb
->pred
->pred_next
== NULL_EDGE
)
1973 rtx last_insn
= then_bb
->end
;
1976 && GET_CODE (last_insn
) == NOTE
1977 && last_insn
!= then_bb
->head
)
1978 last_insn
= PREV_INSN (last_insn
);
1981 && GET_CODE (last_insn
) == JUMP_INSN
1982 && ! simplejump_p (last_insn
))
1986 else_bb
= NULL_BLOCK
;
1992 /* If the THEN block's successor is the other edge out of the TEST block,
1993 then we have an IF-THEN combo without an ELSE. */
1994 else if (then_succ
->dest
== else_bb
)
1997 else_bb
= NULL_BLOCK
;
2000 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
2001 has exactly one predecessor and one successor, and the outgoing edge
2002 is not complex, then we have an IF-THEN-ELSE combo. */
2003 else if (else_succ
!= NULL_EDGE
2004 && then_succ
->dest
== else_succ
->dest
2005 && else_bb
->pred
->pred_next
== NULL_EDGE
2006 && else_succ
->succ_next
== NULL_EDGE
2007 && ! (else_succ
->flags
& EDGE_COMPLEX
))
2008 join_bb
= else_succ
->dest
;
2010 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
2014 num_possible_if_blocks
++;
2019 fprintf (rtl_dump_file
,
2020 "\nIF-THEN-ELSE block found, start %d, then %d, else %d, join %d\n",
2021 test_bb
->index
, then_bb
->index
, else_bb
->index
,
2024 fprintf (rtl_dump_file
,
2025 "\nIF-THEN block found, start %d, then %d, join %d\n",
2026 test_bb
->index
, then_bb
->index
, join_bb
->index
);
2029 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we
2030 get the first condition for free, since we've already asserted that
2031 there's a fallthru edge from IF to THEN. */
2032 /* ??? As an enhancement, move the ELSE block. Have to deal with
2033 BLOCK notes, if by no other means than aborting the merge if they
2034 exist. Sticky enough I don't want to think about it now. */
2035 next_index
= then_bb
->index
;
2036 if (else_bb
&& ++next_index
!= else_bb
->index
)
2038 if (++next_index
!= join_bb
->index
&& join_bb
->index
!= EXIT_BLOCK
)
2046 /* Do the real work. */
2047 return process_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
2050 /* Convert a branch over a trap, or a branch to a trap,
2051 into a conditional trap. */
2054 find_cond_trap (test_bb
, then_edge
, else_edge
)
2055 basic_block test_bb
;
2056 edge then_edge
, else_edge
;
2058 basic_block then_bb
, else_bb
, join_bb
, trap_bb
;
2059 rtx trap
, jump
, cond
, cond_earliest
, seq
;
2062 then_bb
= then_edge
->dest
;
2063 else_bb
= else_edge
->dest
;
2066 /* Locate the block with the trap instruction. */
2067 /* ??? While we look for no successors, we really ought to allow
2068 EH successors. Need to fix merge_if_block for that to work. */
2069 /* ??? We can't currently handle merging the blocks if they are not
2070 already adjacent. Prevent losage in merge_if_block by detecting
2072 if (then_bb
->succ
== NULL
)
2075 if (else_bb
->index
!= then_bb
->index
+ 1)
2080 else if (else_bb
->succ
== NULL
)
2083 if (else_bb
->index
!= then_bb
->index
+ 1)
2085 else if (then_bb
->succ
2086 && ! then_bb
->succ
->succ_next
2087 && ! (then_bb
->succ
->flags
& EDGE_COMPLEX
)
2088 && then_bb
->succ
->dest
->index
== else_bb
->index
+ 1)
2089 join_bb
= then_bb
->succ
->dest
;
2094 /* Don't confuse a conditional return with something we want to
2096 if (trap_bb
== EXIT_BLOCK_PTR
)
2099 /* The only instruction in the THEN block must be the trap. */
2100 trap
= first_active_insn (trap_bb
);
2101 if (! (trap
== trap_bb
->end
2102 && GET_CODE (PATTERN (trap
)) == TRAP_IF
2103 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
2108 if (trap_bb
== then_bb
)
2109 fprintf (rtl_dump_file
,
2110 "\nTRAP-IF block found, start %d, trap %d",
2111 test_bb
->index
, then_bb
->index
);
2113 fprintf (rtl_dump_file
,
2114 "\nTRAP-IF block found, start %d, then %d, trap %d",
2115 test_bb
->index
, then_bb
->index
, trap_bb
->index
);
2117 fprintf (rtl_dump_file
, ", join %d\n", join_bb
->index
);
2119 fputc ('\n', rtl_dump_file
);
2122 /* If this is not a standard conditional jump, we can't parse it. */
2123 jump
= test_bb
->end
;
2124 cond
= noce_get_condition (jump
, &cond_earliest
);
2128 /* If the conditional jump is more than just a conditional jump,
2129 then we can not do if-conversion on this block. */
2130 if (! onlyjump_p (jump
))
2133 /* We must be comparing objects whose modes imply the size. */
2134 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
2137 /* Reverse the comparison code, if necessary. */
2138 code
= GET_CODE (cond
);
2139 if (then_bb
== trap_bb
)
2141 code
= reversed_comparison_code (cond
, jump
);
2142 if (code
== UNKNOWN
)
2146 /* Attempt to generate the conditional trap. */
2147 seq
= gen_cond_trap (code
, XEXP (cond
, 0), XEXP (cond
, 1),
2148 TRAP_CODE (PATTERN (trap
)));
2152 /* Emit the new insns before cond_earliest; delete the old jump
2155 emit_insn_before (seq
, cond_earliest
);
2161 /* Merge the blocks! */
2162 if (trap_bb
!= then_bb
&& ! else_bb
)
2164 flow_delete_block (trap_bb
);
2165 num_removed_blocks
++;
2167 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
2172 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
2173 transformable, but not necessarily the other. There need be no
2176 Return TRUE if we were successful at converting the the block.
2178 Cases we'd like to look at:
2181 if (test) goto over; // x not live
2189 if (! test) goto label;
2192 if (test) goto E; // x not live
2206 (3) // This one's really only interesting for targets that can do
2207 // multiway branching, e.g. IA-64 BBB bundles. For other targets
2208 // it results in multiple branches on a cache line, which often
2209 // does not sit well with predictors.
2211 if (test1) goto E; // predicted not taken
2227 (A) Don't do (2) if the branch is predicted against the block we're
2228 eliminating. Do it anyway if we can eliminate a branch; this requires
2229 that the sole successor of the eliminated block postdominate the other
2232 (B) With CE, on (3) we can steal from both sides of the if, creating
2241 Again, this is most useful if J postdominates.
2243 (C) CE substitutes for helpful life information.
2245 (D) These heuristics need a lot of work. */
2247 /* Tests for case 1 above. */
2250 find_if_case_1 (test_bb
, then_edge
, else_edge
)
2251 basic_block test_bb
;
2252 edge then_edge
, else_edge
;
2254 basic_block then_bb
= then_edge
->dest
;
2255 basic_block else_bb
= else_edge
->dest
, new_bb
;
2256 edge then_succ
= then_bb
->succ
;
2258 /* THEN has one successor. */
2259 if (!then_succ
|| then_succ
->succ_next
!= NULL
)
2262 /* THEN does not fall through, but is not strange either. */
2263 if (then_succ
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
2266 /* THEN has one predecessor. */
2267 if (then_bb
->pred
->pred_next
!= NULL
)
2270 /* THEN must do something. */
2271 if (forwarder_block_p (then_bb
))
2274 num_possible_if_blocks
++;
2276 fprintf (rtl_dump_file
,
2277 "\nIF-CASE-1 found, start %d, then %d\n",
2278 test_bb
->index
, then_bb
->index
);
2280 /* THEN is small. */
2281 if (count_bb_insns (then_bb
) > BRANCH_COST
)
2284 /* Registers set are dead, or are predicable. */
2285 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
2286 then_bb
->succ
->dest
, 1))
2289 /* Conversion went ok, including moving the insns and fixing up the
2290 jump. Adjust the CFG to match. */
2292 bitmap_operation (test_bb
->global_live_at_end
,
2293 else_bb
->global_live_at_start
,
2294 then_bb
->global_live_at_end
, BITMAP_IOR
);
2296 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
), else_bb
);
2297 /* Make rest of code believe that the newly created block is the THEN_BB
2298 block we are going to remove. */
2300 new_bb
->aux
= then_bb
->aux
;
2301 flow_delete_block (then_bb
);
2302 /* We've possibly created jump to next insn, cleanup_cfg will solve that
2305 num_removed_blocks
++;
2306 num_updated_if_blocks
++;
2311 /* Test for case 2 above. */
2314 find_if_case_2 (test_bb
, then_edge
, else_edge
)
2315 basic_block test_bb
;
2316 edge then_edge
, else_edge
;
2318 basic_block then_bb
= then_edge
->dest
;
2319 basic_block else_bb
= else_edge
->dest
;
2320 edge else_succ
= else_bb
->succ
;
2323 /* ELSE has one successor. */
2324 if (!else_succ
|| else_succ
->succ_next
!= NULL
)
2327 /* ELSE outgoing edge is not complex. */
2328 if (else_succ
->flags
& EDGE_COMPLEX
)
2331 /* ELSE has one predecessor. */
2332 if (else_bb
->pred
->pred_next
!= NULL
)
2335 /* THEN is not EXIT. */
2336 if (then_bb
->index
< 0)
2339 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
2340 note
= find_reg_note (test_bb
->end
, REG_BR_PROB
, NULL_RTX
);
2341 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
2343 else if (else_succ
->dest
->index
< 0
2344 || TEST_BIT (post_dominators
[ORIG_INDEX (then_bb
)],
2345 ORIG_INDEX (else_succ
->dest
)))
2350 num_possible_if_blocks
++;
2352 fprintf (rtl_dump_file
,
2353 "\nIF-CASE-2 found, start %d, else %d\n",
2354 test_bb
->index
, else_bb
->index
);
2356 /* ELSE is small. */
2357 if (count_bb_insns (then_bb
) > BRANCH_COST
)
2360 /* Registers set are dead, or are predicable. */
2361 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
2364 /* Conversion went ok, including moving the insns and fixing up the
2365 jump. Adjust the CFG to match. */
2367 bitmap_operation (test_bb
->global_live_at_end
,
2368 then_bb
->global_live_at_start
,
2369 else_bb
->global_live_at_end
, BITMAP_IOR
);
2371 flow_delete_block (else_bb
);
2373 num_removed_blocks
++;
2374 num_updated_if_blocks
++;
2376 /* ??? We may now fallthru from one of THEN's successors into a join
2377 block. Rerun cleanup_cfg? Examine things manually? Wait? */
2382 /* A subroutine of dead_or_predicable called through for_each_rtx.
2383 Return 1 if a memory is found. */
2386 find_memory (px
, data
)
2388 void *data ATTRIBUTE_UNUSED
;
2390 return GET_CODE (*px
) == MEM
;
2393 /* Used by the code above to perform the actual rtl transformations.
2394 Return TRUE if successful.
2396 TEST_BB is the block containing the conditional branch. MERGE_BB
2397 is the block containing the code to manipulate. NEW_DEST is the
2398 label TEST_BB should be branching to after the conversion.
2399 REVERSEP is true if the sense of the branch should be reversed. */
2402 dead_or_predicable (test_bb
, merge_bb
, other_bb
, new_dest
, reversep
)
2403 basic_block test_bb
, merge_bb
, other_bb
;
2404 basic_block new_dest
;
2407 rtx head
, end
, jump
, earliest
, old_dest
, new_label
= NULL_RTX
;
2409 jump
= test_bb
->end
;
2411 /* Find the extent of the real code in the merge block. */
2412 head
= merge_bb
->head
;
2413 end
= merge_bb
->end
;
2415 if (GET_CODE (head
) == CODE_LABEL
)
2416 head
= NEXT_INSN (head
);
2417 if (GET_CODE (head
) == NOTE
)
2421 head
= end
= NULL_RTX
;
2424 head
= NEXT_INSN (head
);
2427 if (GET_CODE (end
) == JUMP_INSN
)
2431 head
= end
= NULL_RTX
;
2434 end
= PREV_INSN (end
);
2437 /* Disable handling dead code by conditional execution if the machine needs
2438 to do anything funny with the tests, etc. */
2439 #ifndef IFCVT_MODIFY_TESTS
2440 if (HAVE_conditional_execution
)
2442 /* In the conditional execution case, we have things easy. We know
2443 the condition is reversable. We don't have to check life info,
2444 becase we're going to conditionally execute the code anyway.
2445 All that's left is making sure the insns involved can actually
2450 cond
= cond_exec_get_condition (jump
);
2454 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
2456 prob_val
= XEXP (prob_val
, 0);
2460 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
2463 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
2466 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
2469 if (! cond_exec_process_insns (head
, end
, cond
, prob_val
, 0))
2477 /* In the non-conditional execution case, we have to verify that there
2478 are no trapping operations, no calls, no references to memory, and
2479 that any registers modified are dead at the branch site. */
2481 rtx insn
, cond
, prev
;
2482 regset_head merge_set_head
, tmp_head
, test_live_head
, test_set_head
;
2483 regset merge_set
, tmp
, test_live
, test_set
;
2484 struct propagate_block_info
*pbi
;
2487 /* Check for no calls or trapping operations. */
2488 for (insn
= head
; ; insn
= NEXT_INSN (insn
))
2490 if (GET_CODE (insn
) == CALL_INSN
)
2494 if (may_trap_p (PATTERN (insn
)))
2497 /* ??? Even non-trapping memories such as stack frame
2498 references must be avoided. For stores, we collect
2499 no lifetime info; for reads, we'd have to assert
2500 true_dependence false against every store in the
2502 if (for_each_rtx (&PATTERN (insn
), find_memory
, NULL
))
2509 if (! any_condjump_p (jump
))
2512 /* Find the extent of the conditional. */
2513 cond
= noce_get_condition (jump
, &earliest
);
2518 MERGE_SET = set of registers set in MERGE_BB
2519 TEST_LIVE = set of registers live at EARLIEST
2520 TEST_SET = set of registers set between EARLIEST and the
2521 end of the block. */
2523 tmp
= INITIALIZE_REG_SET (tmp_head
);
2524 merge_set
= INITIALIZE_REG_SET (merge_set_head
);
2525 test_live
= INITIALIZE_REG_SET (test_live_head
);
2526 test_set
= INITIALIZE_REG_SET (test_set_head
);
2528 /* ??? bb->local_set is only valid during calculate_global_regs_live,
2529 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
2530 since we've already asserted that MERGE_BB is small. */
2531 propagate_block (merge_bb
, tmp
, merge_set
, merge_set
, 0);
2533 /* For small register class machines, don't lengthen lifetimes of
2534 hard registers before reload. */
2535 if (SMALL_REGISTER_CLASSES
&& ! reload_completed
)
2537 EXECUTE_IF_SET_IN_BITMAP
2540 if (i
< FIRST_PSEUDO_REGISTER
2542 && ! global_regs
[i
])
2547 /* For TEST, we're interested in a range of insns, not a whole block.
2548 Moreover, we're interested in the insns live from OTHER_BB. */
2550 COPY_REG_SET (test_live
, other_bb
->global_live_at_start
);
2551 pbi
= init_propagate_block_info (test_bb
, test_live
, test_set
, test_set
,
2554 for (insn
= jump
; ; insn
= prev
)
2556 prev
= propagate_one_insn (pbi
, insn
);
2557 if (insn
== earliest
)
2561 free_propagate_block_info (pbi
);
2563 /* We can perform the transformation if
2564 MERGE_SET & (TEST_SET | TEST_LIVE)
2566 TEST_SET & merge_bb->global_live_at_start
2569 bitmap_operation (tmp
, test_set
, test_live
, BITMAP_IOR
);
2570 bitmap_operation (tmp
, tmp
, merge_set
, BITMAP_AND
);
2571 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
2573 bitmap_operation (tmp
, test_set
, merge_bb
->global_live_at_start
,
2575 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
2578 FREE_REG_SET (merge_set
);
2579 FREE_REG_SET (test_live
);
2580 FREE_REG_SET (test_set
);
2587 /* We don't want to use normal invert_jump or redirect_jump because
2588 we don't want to delete_insn called. Also, we want to do our own
2589 change group management. */
2591 old_dest
= JUMP_LABEL (jump
);
2592 if (other_bb
!= new_dest
)
2594 new_label
= block_label (new_dest
);
2596 ? ! invert_jump_1 (jump
, new_label
)
2597 : ! redirect_jump_1 (jump
, new_label
))
2601 if (! apply_change_group ())
2604 if (other_bb
!= new_dest
)
2607 LABEL_NUSES (old_dest
) -= 1;
2609 LABEL_NUSES (new_label
) += 1;
2610 JUMP_LABEL (jump
) = new_label
;
2612 invert_br_probabilities (jump
);
2614 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
2617 gcov_type count
, probability
;
2618 count
= BRANCH_EDGE (test_bb
)->count
;
2619 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
2620 FALLTHRU_EDGE (test_bb
)->count
= count
;
2621 probability
= BRANCH_EDGE (test_bb
)->probability
;
2622 BRANCH_EDGE (test_bb
)->probability
2623 = FALLTHRU_EDGE (test_bb
)->probability
;
2624 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
2625 update_br_prob_note (test_bb
);
2629 /* Move the insns out of MERGE_BB to before the branch. */
2632 if (end
== merge_bb
->end
)
2633 merge_bb
->end
= PREV_INSN (head
);
2635 if (squeeze_notes (&head
, &end
))
2638 reorder_insns (head
, end
, PREV_INSN (earliest
));
2641 /* Remove the jump and edge if we can. */
2642 if (other_bb
== new_dest
)
2645 remove_edge (BRANCH_EDGE (test_bb
));
2646 /* ??? Can't merge blocks here, as then_bb is still in use.
2647 At minimum, the merge will get done just before bb-reorder. */
2657 /* Main entry point for all if-conversion. */
2660 if_convert (x_life_data_ok
)
2665 num_possible_if_blocks
= 0;
2666 num_updated_if_blocks
= 0;
2667 num_removed_blocks
= 0;
2668 life_data_ok
= (x_life_data_ok
!= 0);
2670 /* Free up basic_block_for_insn so that we don't have to keep it
2671 up to date, either here or in merge_blocks_nomove. */
2672 free_basic_block_vars (1);
2674 /* Compute postdominators if we think we'll use them. */
2675 post_dominators
= NULL
;
2676 if (HAVE_conditional_execution
|| life_data_ok
)
2678 post_dominators
= sbitmap_vector_alloc (n_basic_blocks
, n_basic_blocks
);
2679 calculate_dominance_info (NULL
, post_dominators
, CDI_POST_DOMINATORS
);
2684 /* Record initial block numbers. */
2685 for (block_num
= 0; block_num
< n_basic_blocks
; block_num
++)
2686 SET_ORIG_INDEX (BASIC_BLOCK (block_num
), block_num
);
2688 /* Go through each of the basic blocks looking for things to convert. */
2689 for (block_num
= 0; block_num
< n_basic_blocks
; )
2691 basic_block bb
= BASIC_BLOCK (block_num
);
2692 if (find_if_header (bb
))
2693 block_num
= bb
->index
;
2698 if (post_dominators
)
2699 sbitmap_vector_free (post_dominators
);
2702 fflush (rtl_dump_file
);
2704 clear_aux_for_blocks ();
2706 /* Rebuild life info for basic blocks that require it. */
2707 if (num_removed_blocks
&& life_data_ok
)
2709 /* If we allocated new pseudos, we must resize the array for sched1. */
2710 if (max_regno
< max_reg_num ())
2712 max_regno
= max_reg_num ();
2713 allocate_reg_info (max_regno
, FALSE
, FALSE
);
2715 update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES
,
2716 PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
2717 | PROP_KILL_DEAD_CODE
);
2720 /* Write the final stats. */
2721 if (rtl_dump_file
&& num_possible_if_blocks
> 0)
2723 fprintf (rtl_dump_file
,
2724 "\n%d possible IF blocks searched.\n",
2725 num_possible_if_blocks
);
2726 fprintf (rtl_dump_file
,
2727 "%d IF blocks converted.\n",
2728 num_updated_if_blocks
);
2729 fprintf (rtl_dump_file
,
2730 "%d basic blocks deleted.\n\n\n",
2731 num_removed_blocks
);
2734 #ifdef ENABLE_CHECKING
2735 verify_flow_info ();