1 /* If-conversion support.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
24 #include "coretypes.h"
31 #include "insn-config.h"
34 #include "hard-reg-set.h"
35 #include "basic-block.h"
46 #ifndef HAVE_conditional_execution
47 #define HAVE_conditional_execution 0
49 #ifndef HAVE_conditional_move
50 #define HAVE_conditional_move 0
61 #ifndef HAVE_conditional_trap
62 #define HAVE_conditional_trap 0
65 #ifndef MAX_CONDITIONAL_EXECUTE
66 #define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1)
69 #define NULL_BLOCK ((basic_block) NULL)
71 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
72 static int num_possible_if_blocks
;
74 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
76 static int num_updated_if_blocks
;
78 /* # of changes made which require life information to be updated. */
79 static int num_true_changes
;
81 /* Whether conditional execution changes were made. */
82 static int cond_exec_changed_p
;
84 /* True if life data ok at present. */
85 static bool life_data_ok
;
87 /* Forward references. */
88 static int count_bb_insns (basic_block
);
89 static bool cheap_bb_rtx_cost_p (basic_block
, int);
90 static rtx
first_active_insn (basic_block
);
91 static rtx
last_active_insn (basic_block
, int);
92 static basic_block
block_fallthru (basic_block
);
93 static int cond_exec_process_insns (ce_if_block_t
*, rtx
, rtx
, rtx
, rtx
, int);
94 static rtx
cond_exec_get_condition (rtx
);
95 static int cond_exec_process_if_block (ce_if_block_t
*, int);
96 static rtx
noce_get_condition (rtx
, rtx
*);
97 static int noce_operand_ok (rtx
);
98 static int noce_process_if_block (ce_if_block_t
*);
99 static int process_if_block (ce_if_block_t
*);
100 static void merge_if_block (ce_if_block_t
*);
101 static int find_cond_trap (basic_block
, edge
, edge
);
102 static basic_block
find_if_header (basic_block
, int);
103 static int block_jumps_and_fallthru_p (basic_block
, basic_block
);
104 static int find_if_block (ce_if_block_t
*);
105 static int find_if_case_1 (basic_block
, edge
, edge
);
106 static int find_if_case_2 (basic_block
, edge
, edge
);
107 static int find_memory (rtx
*, void *);
108 static int dead_or_predicable (basic_block
, basic_block
, basic_block
,
110 static void noce_emit_move_insn (rtx
, rtx
);
111 static rtx
block_has_only_trap (basic_block
);
113 /* Count the number of non-jump active insns in BB. */
116 count_bb_insns (basic_block bb
)
119 rtx insn
= BB_HEAD (bb
);
123 if (CALL_P (insn
) || NONJUMP_INSN_P (insn
))
126 if (insn
== BB_END (bb
))
128 insn
= NEXT_INSN (insn
);
134 /* Determine whether the total insn_rtx_cost on non-jump insns in
135 basic block BB is less than MAX_COST. This function returns
136 false if the cost of any instruction could not be estimated. */
139 cheap_bb_rtx_cost_p (basic_block bb
, int max_cost
)
142 rtx insn
= BB_HEAD (bb
);
146 if (NONJUMP_INSN_P (insn
))
148 int cost
= insn_rtx_cost (PATTERN (insn
));
152 /* If this instruction is the load or set of a "stack" register,
153 such as a floating point register on x87, then the cost of
154 speculatively executing this instruction needs to include
155 the additional cost of popping this register off of the
159 rtx set
= single_set (insn
);
160 if (set
&& STACK_REG_P (SET_DEST (set
)))
161 cost
+= COSTS_N_INSNS (1);
166 if (count
>= max_cost
)
169 else if (CALL_P (insn
))
172 if (insn
== BB_END (bb
))
174 insn
= NEXT_INSN (insn
);
180 /* Return the first non-jump active insn in the basic block. */
183 first_active_insn (basic_block bb
)
185 rtx insn
= BB_HEAD (bb
);
189 if (insn
== BB_END (bb
))
191 insn
= NEXT_INSN (insn
);
194 while (NOTE_P (insn
))
196 if (insn
== BB_END (bb
))
198 insn
= NEXT_INSN (insn
);
207 /* Return the last non-jump active (non-jump) insn in the basic block. */
210 last_active_insn (basic_block bb
, int skip_use_p
)
212 rtx insn
= BB_END (bb
);
213 rtx head
= BB_HEAD (bb
);
218 && NONJUMP_INSN_P (insn
)
219 && GET_CODE (PATTERN (insn
)) == USE
))
223 insn
= PREV_INSN (insn
);
232 /* Return the basic block reached by falling though the basic block BB. */
235 block_fallthru (basic_block bb
)
240 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
241 if (e
->flags
& EDGE_FALLTHRU
)
244 return (e
) ? e
->dest
: NULL_BLOCK
;
247 /* Go through a bunch of insns, converting them to conditional
248 execution format if possible. Return TRUE if all of the non-note
249 insns were processed. */
252 cond_exec_process_insns (ce_if_block_t
*ce_info ATTRIBUTE_UNUSED
,
253 /* if block information */rtx start
,
254 /* first insn to look at */rtx end
,
255 /* last insn to look at */rtx test
,
256 /* conditional execution test */rtx prob_val
,
257 /* probability of branch taken. */int mod_ok
)
259 int must_be_last
= FALSE
;
267 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
272 gcc_assert(NONJUMP_INSN_P (insn
) || CALL_P (insn
));
274 /* Remove USE insns that get in the way. */
275 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
277 /* ??? Ug. Actually unlinking the thing is problematic,
278 given what we'd have to coordinate with our callers. */
279 SET_INSN_DELETED (insn
);
283 /* Last insn wasn't last? */
287 if (modified_in_p (test
, insn
))
294 /* Now build the conditional form of the instruction. */
295 pattern
= PATTERN (insn
);
296 xtest
= copy_rtx (test
);
298 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
300 if (GET_CODE (pattern
) == COND_EXEC
)
302 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
305 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
306 COND_EXEC_TEST (pattern
));
307 pattern
= COND_EXEC_CODE (pattern
);
310 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
312 /* If the machine needs to modify the insn being conditionally executed,
313 say for example to force a constant integer operand into a temp
314 register, do so here. */
315 #ifdef IFCVT_MODIFY_INSN
316 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
321 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
323 if (CALL_P (insn
) && prob_val
)
324 validate_change (insn
, ®_NOTES (insn
),
325 alloc_EXPR_LIST (REG_BR_PROB
, prob_val
,
326 REG_NOTES (insn
)), 1);
336 /* Return the condition for a jump. Do not do any special processing. */
339 cond_exec_get_condition (rtx jump
)
343 if (any_condjump_p (jump
))
344 test_if
= SET_SRC (pc_set (jump
));
347 cond
= XEXP (test_if
, 0);
349 /* If this branches to JUMP_LABEL when the condition is false,
350 reverse the condition. */
351 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
352 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
354 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
358 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
365 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
366 to conditional execution. Return TRUE if we were successful at
367 converting the block. */
370 cond_exec_process_if_block (ce_if_block_t
* ce_info
,
371 /* if block information */int do_multiple_p
)
373 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
374 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
375 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
376 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
377 rtx then_start
; /* first insn in THEN block */
378 rtx then_end
; /* last insn + 1 in THEN block */
379 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
380 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
381 int max
; /* max # of insns to convert. */
382 int then_mod_ok
; /* whether conditional mods are ok in THEN */
383 rtx true_expr
; /* test for else block insns */
384 rtx false_expr
; /* test for then block insns */
385 rtx true_prob_val
; /* probability of else block */
386 rtx false_prob_val
; /* probability of then block */
388 enum rtx_code false_code
;
390 /* If test is comprised of && or || elements, and we've failed at handling
391 all of them together, just use the last test if it is the special case of
392 && elements without an ELSE block. */
393 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
395 if (else_bb
|| ! ce_info
->and_and_p
)
398 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
399 ce_info
->num_multiple_test_blocks
= 0;
400 ce_info
->num_and_and_blocks
= 0;
401 ce_info
->num_or_or_blocks
= 0;
404 /* Find the conditional jump to the ELSE or JOIN part, and isolate
406 test_expr
= cond_exec_get_condition (BB_END (test_bb
));
410 /* If the conditional jump is more than just a conditional jump,
411 then we can not do conditional execution conversion on this block. */
412 if (! onlyjump_p (BB_END (test_bb
)))
415 /* Collect the bounds of where we're to search, skipping any labels, jumps
416 and notes at the beginning and end of the block. Then count the total
417 number of insns and see if it is small enough to convert. */
418 then_start
= first_active_insn (then_bb
);
419 then_end
= last_active_insn (then_bb
, TRUE
);
420 n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
421 max
= MAX_CONDITIONAL_EXECUTE
;
426 else_start
= first_active_insn (else_bb
);
427 else_end
= last_active_insn (else_bb
, TRUE
);
428 n_insns
+= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
434 /* Map test_expr/test_jump into the appropriate MD tests to use on
435 the conditionally executed code. */
437 true_expr
= test_expr
;
439 false_code
= reversed_comparison_code (true_expr
, BB_END (test_bb
));
440 if (false_code
!= UNKNOWN
)
441 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
442 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
444 false_expr
= NULL_RTX
;
446 #ifdef IFCVT_MODIFY_TESTS
447 /* If the machine description needs to modify the tests, such as setting a
448 conditional execution register from a comparison, it can do so here. */
449 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
451 /* See if the conversion failed. */
452 if (!true_expr
|| !false_expr
)
456 true_prob_val
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
459 true_prob_val
= XEXP (true_prob_val
, 0);
460 false_prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (true_prob_val
));
463 false_prob_val
= NULL_RTX
;
465 /* If we have && or || tests, do them here. These tests are in the adjacent
466 blocks after the first block containing the test. */
467 if (ce_info
->num_multiple_test_blocks
> 0)
469 basic_block bb
= test_bb
;
470 basic_block last_test_bb
= ce_info
->last_test_bb
;
479 enum rtx_code f_code
;
481 bb
= block_fallthru (bb
);
482 start
= first_active_insn (bb
);
483 end
= last_active_insn (bb
, TRUE
);
485 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
486 false_prob_val
, FALSE
))
489 /* If the conditional jump is more than just a conditional jump, then
490 we can not do conditional execution conversion on this block. */
491 if (! onlyjump_p (BB_END (bb
)))
494 /* Find the conditional jump and isolate the test. */
495 t
= cond_exec_get_condition (BB_END (bb
));
499 f_code
= reversed_comparison_code (t
, BB_END (bb
));
500 if (f_code
== UNKNOWN
)
503 f
= gen_rtx_fmt_ee (f_code
, GET_MODE (t
), XEXP (t
, 0), XEXP (t
, 1));
504 if (ce_info
->and_and_p
)
506 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
507 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
511 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
512 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
515 /* If the machine description needs to modify the tests, such as
516 setting a conditional execution register from a comparison, it can
518 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
519 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
521 /* See if the conversion failed. */
529 while (bb
!= last_test_bb
);
532 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
533 on then THEN block. */
534 then_mod_ok
= (else_bb
== NULL_BLOCK
);
536 /* Go through the THEN and ELSE blocks converting the insns if possible
537 to conditional execution. */
541 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
542 false_expr
, false_prob_val
,
546 if (else_bb
&& else_end
547 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
548 true_expr
, true_prob_val
, TRUE
))
551 /* If we cannot apply the changes, fail. Do not go through the normal fail
552 processing, since apply_change_group will call cancel_changes. */
553 if (! apply_change_group ())
555 #ifdef IFCVT_MODIFY_CANCEL
556 /* Cancel any machine dependent changes. */
557 IFCVT_MODIFY_CANCEL (ce_info
);
562 #ifdef IFCVT_MODIFY_FINAL
563 /* Do any machine dependent final modifications. */
564 IFCVT_MODIFY_FINAL (ce_info
);
567 /* Conversion succeeded. */
569 fprintf (dump_file
, "%d insn%s converted to conditional execution.\n",
570 n_insns
, (n_insns
== 1) ? " was" : "s were");
572 /* Merge the blocks! */
573 merge_if_block (ce_info
);
574 cond_exec_changed_p
= TRUE
;
578 #ifdef IFCVT_MODIFY_CANCEL
579 /* Cancel any machine dependent changes. */
580 IFCVT_MODIFY_CANCEL (ce_info
);
587 /* Used by noce_process_if_block to communicate with its subroutines.
589 The subroutines know that A and B may be evaluated freely. They
590 know that X is a register. They should insert new instructions
591 before cond_earliest. */
598 rtx jump
, cond
, cond_earliest
;
599 /* True if "b" was originally evaluated unconditionally. */
600 bool b_unconditional
;
603 static rtx
noce_emit_store_flag (struct noce_if_info
*, rtx
, int, int);
604 static int noce_try_move (struct noce_if_info
*);
605 static int noce_try_store_flag (struct noce_if_info
*);
606 static int noce_try_addcc (struct noce_if_info
*);
607 static int noce_try_store_flag_constants (struct noce_if_info
*);
608 static int noce_try_store_flag_mask (struct noce_if_info
*);
609 static rtx
noce_emit_cmove (struct noce_if_info
*, rtx
, enum rtx_code
, rtx
,
611 static int noce_try_cmove (struct noce_if_info
*);
612 static int noce_try_cmove_arith (struct noce_if_info
*);
613 static rtx
noce_get_alt_condition (struct noce_if_info
*, rtx
, rtx
*);
614 static int noce_try_minmax (struct noce_if_info
*);
615 static int noce_try_abs (struct noce_if_info
*);
616 static int noce_try_sign_mask (struct noce_if_info
*);
618 /* Helper function for noce_try_store_flag*. */
621 noce_emit_store_flag (struct noce_if_info
*if_info
, rtx x
, int reversep
,
624 rtx cond
= if_info
->cond
;
628 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
629 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
631 /* If earliest == jump, or when the condition is complex, try to
632 build the store_flag insn directly. */
635 cond
= XEXP (SET_SRC (pc_set (if_info
->jump
)), 0);
638 code
= reversed_comparison_code (cond
, if_info
->jump
);
640 code
= GET_CODE (cond
);
642 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
643 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
647 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
649 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
652 tmp
= emit_insn (tmp
);
654 if (recog_memoized (tmp
) >= 0)
660 if_info
->cond_earliest
= if_info
->jump
;
668 /* Don't even try if the comparison operands or the mode of X are weird. */
669 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
672 return emit_store_flag (x
, code
, XEXP (cond
, 0),
673 XEXP (cond
, 1), VOIDmode
,
674 (code
== LTU
|| code
== LEU
675 || code
== GEU
|| code
== GTU
), normalize
);
678 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
679 X is the destination/target and Y is the value to copy. */
682 noce_emit_move_insn (rtx x
, rtx y
)
684 enum machine_mode outmode
;
688 if (GET_CODE (x
) != STRICT_LOW_PART
)
690 rtx seq
, insn
, target
;
694 insn
= emit_move_insn (x
, y
);
698 if (recog_memoized (insn
) <= 0)
699 switch (GET_RTX_CLASS (GET_CODE (y
)))
702 ot
= code_to_optab
[GET_CODE (y
)];
706 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
707 if (target
!= NULL_RTX
)
710 emit_move_insn (x
, target
);
719 ot
= code_to_optab
[GET_CODE (y
)];
723 target
= expand_binop (GET_MODE (y
), ot
,
724 XEXP (y
, 0), XEXP (y
, 1),
726 if (target
!= NULL_RTX
)
729 emit_move_insn (x
, target
);
745 inner
= XEXP (outer
, 0);
746 outmode
= GET_MODE (outer
);
747 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
748 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
, outmode
, y
);
751 /* Return sequence of instructions generated by if conversion. This
752 function calls end_sequence() to end the current stream, ensures
753 that are instructions are unshared, recognizable non-jump insns.
754 On failure, this function returns a NULL_RTX. */
757 end_ifcvt_sequence (struct noce_if_info
*if_info
)
760 rtx seq
= get_insns ();
762 set_used_flags (if_info
->x
);
763 set_used_flags (if_info
->cond
);
764 unshare_all_rtl_in_chain (seq
);
767 /* Make sure that all of the instructions emitted are recognizable,
768 and that we haven't introduced a new jump instruction.
769 As an exercise for the reader, build a general mechanism that
770 allows proper placement of required clobbers. */
771 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
773 || recog_memoized (insn
) == -1)
779 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
780 "if (a == b) x = a; else x = b" into "x = b". */
783 noce_try_move (struct noce_if_info
*if_info
)
785 rtx cond
= if_info
->cond
;
786 enum rtx_code code
= GET_CODE (cond
);
789 if (code
!= NE
&& code
!= EQ
)
792 /* This optimization isn't valid if either A or B could be a NaN
794 if (HONOR_NANS (GET_MODE (if_info
->x
))
795 || HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
798 /* Check whether the operands of the comparison are A and in
800 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
801 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
802 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
803 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
805 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
807 /* Avoid generating the move if the source is the destination. */
808 if (! rtx_equal_p (if_info
->x
, y
))
811 noce_emit_move_insn (if_info
->x
, y
);
812 seq
= end_ifcvt_sequence (if_info
);
816 emit_insn_before_setloc (seq
, if_info
->jump
,
817 INSN_LOCATOR (if_info
->insn_a
));
824 /* Convert "if (test) x = 1; else x = 0".
826 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
827 tried in noce_try_store_flag_constants after noce_try_cmove has had
828 a go at the conversion. */
831 noce_try_store_flag (struct noce_if_info
*if_info
)
836 if (GET_CODE (if_info
->b
) == CONST_INT
837 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
838 && if_info
->a
== const0_rtx
)
840 else if (if_info
->b
== const0_rtx
841 && GET_CODE (if_info
->a
) == CONST_INT
842 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
843 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
851 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
854 if (target
!= if_info
->x
)
855 noce_emit_move_insn (if_info
->x
, target
);
857 seq
= end_ifcvt_sequence (if_info
);
861 emit_insn_before_setloc (seq
, if_info
->jump
,
862 INSN_LOCATOR (if_info
->insn_a
));
872 /* Convert "if (test) x = a; else x = b", for A and B constant. */
875 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
879 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
880 int normalize
, can_reverse
;
881 enum machine_mode mode
;
884 && GET_CODE (if_info
->a
) == CONST_INT
885 && GET_CODE (if_info
->b
) == CONST_INT
)
887 mode
= GET_MODE (if_info
->x
);
888 ifalse
= INTVAL (if_info
->a
);
889 itrue
= INTVAL (if_info
->b
);
891 /* Make sure we can represent the difference between the two values. */
892 if ((itrue
- ifalse
> 0)
893 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
896 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
898 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
902 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
904 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
905 && (STORE_FLAG_VALUE
== 1
906 || BRANCH_COST
>= 2))
908 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
909 && (STORE_FLAG_VALUE
== 1 || BRANCH_COST
>= 2))
910 normalize
= 1, reversep
= 1;
912 && (STORE_FLAG_VALUE
== -1
913 || BRANCH_COST
>= 2))
915 else if (ifalse
== -1 && can_reverse
916 && (STORE_FLAG_VALUE
== -1 || BRANCH_COST
>= 2))
917 normalize
= -1, reversep
= 1;
918 else if ((BRANCH_COST
>= 2 && STORE_FLAG_VALUE
== -1)
926 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
927 diff
= trunc_int_for_mode (-diff
, mode
);
931 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
938 /* if (test) x = 3; else x = 4;
939 => x = 3 + (test == 0); */
940 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
942 target
= expand_simple_binop (mode
,
943 (diff
== STORE_FLAG_VALUE
945 GEN_INT (ifalse
), target
, if_info
->x
, 0,
949 /* if (test) x = 8; else x = 0;
950 => x = (test != 0) << 3; */
951 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
953 target
= expand_simple_binop (mode
, ASHIFT
,
954 target
, GEN_INT (tmp
), if_info
->x
, 0,
958 /* if (test) x = -1; else x = b;
959 => x = -(test != 0) | b; */
960 else if (itrue
== -1)
962 target
= expand_simple_binop (mode
, IOR
,
963 target
, GEN_INT (ifalse
), if_info
->x
, 0,
967 /* if (test) x = a; else x = b;
968 => x = (-(test != 0) & (b - a)) + a; */
971 target
= expand_simple_binop (mode
, AND
,
972 target
, GEN_INT (diff
), if_info
->x
, 0,
975 target
= expand_simple_binop (mode
, PLUS
,
976 target
, GEN_INT (ifalse
),
977 if_info
->x
, 0, OPTAB_WIDEN
);
986 if (target
!= if_info
->x
)
987 noce_emit_move_insn (if_info
->x
, target
);
989 seq
= end_ifcvt_sequence (if_info
);
993 emit_insn_before_setloc (seq
, if_info
->jump
,
994 INSN_LOCATOR (if_info
->insn_a
));
1001 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1002 similarly for "foo--". */
1005 noce_try_addcc (struct noce_if_info
*if_info
)
1008 int subtract
, normalize
;
1010 if (! no_new_pseudos
1011 && GET_CODE (if_info
->a
) == PLUS
1012 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1013 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1016 rtx cond
= if_info
->cond
;
1017 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1019 /* First try to use addcc pattern. */
1020 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1021 && general_operand (XEXP (cond
, 1), VOIDmode
))
1024 target
= emit_conditional_add (if_info
->x
, code
,
1029 XEXP (if_info
->a
, 1),
1030 GET_MODE (if_info
->x
),
1031 (code
== LTU
|| code
== GEU
1032 || code
== LEU
|| code
== GTU
));
1035 if (target
!= if_info
->x
)
1036 noce_emit_move_insn (if_info
->x
, target
);
1038 seq
= end_ifcvt_sequence (if_info
);
1042 emit_insn_before_setloc (seq
, if_info
->jump
,
1043 INSN_LOCATOR (if_info
->insn_a
));
1049 /* If that fails, construct conditional increment or decrement using
1051 if (BRANCH_COST
>= 2
1052 && (XEXP (if_info
->a
, 1) == const1_rtx
1053 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1056 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1057 subtract
= 0, normalize
= 0;
1058 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1059 subtract
= 1, normalize
= 0;
1061 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1064 target
= noce_emit_store_flag (if_info
,
1065 gen_reg_rtx (GET_MODE (if_info
->x
)),
1069 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1070 subtract
? MINUS
: PLUS
,
1071 if_info
->b
, target
, if_info
->x
,
1075 if (target
!= if_info
->x
)
1076 noce_emit_move_insn (if_info
->x
, target
);
1078 seq
= end_ifcvt_sequence (if_info
);
1082 emit_insn_before_setloc (seq
, if_info
->jump
,
1083 INSN_LOCATOR (if_info
->insn_a
));
1093 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1096 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1102 if (! no_new_pseudos
1103 && (BRANCH_COST
>= 2
1104 || STORE_FLAG_VALUE
== -1)
1105 && ((if_info
->a
== const0_rtx
1106 && rtx_equal_p (if_info
->b
, if_info
->x
))
1107 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1110 && if_info
->b
== const0_rtx
1111 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1114 target
= noce_emit_store_flag (if_info
,
1115 gen_reg_rtx (GET_MODE (if_info
->x
)),
1118 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1120 target
, if_info
->x
, 0,
1125 if (target
!= if_info
->x
)
1126 noce_emit_move_insn (if_info
->x
, target
);
1128 seq
= end_ifcvt_sequence (if_info
);
1132 emit_insn_before_setloc (seq
, if_info
->jump
,
1133 INSN_LOCATOR (if_info
->insn_a
));
1143 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1146 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1147 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1149 /* If earliest == jump, try to build the cmove insn directly.
1150 This is helpful when combine has created some complex condition
1151 (like for alpha's cmovlbs) that we can't hope to regenerate
1152 through the normal interface. */
1154 if (if_info
->cond_earliest
== if_info
->jump
)
1158 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1159 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
1160 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
1163 tmp
= emit_insn (tmp
);
1165 if (recog_memoized (tmp
) >= 0)
1177 /* Don't even try if the comparison operands are weird. */
1178 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1179 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1182 #if HAVE_conditional_move
1183 return emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1184 vtrue
, vfalse
, GET_MODE (x
),
1185 (code
== LTU
|| code
== GEU
1186 || code
== LEU
|| code
== GTU
));
1188 /* We'll never get here, as noce_process_if_block doesn't call the
1189 functions involved. Ifdef code, however, should be discouraged
1190 because it leads to typos in the code not selected. However,
1191 emit_conditional_move won't exist either. */
1196 /* Try only simple constants and registers here. More complex cases
1197 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1198 has had a go at it. */
1201 noce_try_cmove (struct noce_if_info
*if_info
)
1206 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1207 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1211 code
= GET_CODE (if_info
->cond
);
1212 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1213 XEXP (if_info
->cond
, 0),
1214 XEXP (if_info
->cond
, 1),
1215 if_info
->a
, if_info
->b
);
1219 if (target
!= if_info
->x
)
1220 noce_emit_move_insn (if_info
->x
, target
);
1222 seq
= end_ifcvt_sequence (if_info
);
1226 emit_insn_before_setloc (seq
, if_info
->jump
,
1227 INSN_LOCATOR (if_info
->insn_a
));
1240 /* Try more complex cases involving conditional_move. */
1243 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1255 /* A conditional move from two memory sources is equivalent to a
1256 conditional on their addresses followed by a load. Don't do this
1257 early because it'll screw alias analysis. Note that we've
1258 already checked for no side effects. */
1259 if (! no_new_pseudos
&& cse_not_expected
1260 && MEM_P (a
) && MEM_P (b
)
1261 && BRANCH_COST
>= 5)
1265 x
= gen_reg_rtx (Pmode
);
1269 /* ??? We could handle this if we knew that a load from A or B could
1270 not fault. This is also true if we've already loaded
1271 from the address along the path from ENTRY. */
1272 else if (may_trap_p (a
) || may_trap_p (b
))
1275 /* if (test) x = a + b; else x = c - d;
1282 code
= GET_CODE (if_info
->cond
);
1283 insn_a
= if_info
->insn_a
;
1284 insn_b
= if_info
->insn_b
;
1286 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1287 if insn_rtx_cost can't be estimated. */
1290 insn_cost
= insn_rtx_cost (PATTERN (insn_a
));
1291 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (BRANCH_COST
))
1300 insn_cost
+= insn_rtx_cost (PATTERN (insn_b
));
1301 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (BRANCH_COST
))
1305 /* Possibly rearrange operands to make things come out more natural. */
1306 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1309 if (rtx_equal_p (b
, x
))
1311 else if (general_operand (b
, GET_MODE (b
)))
1316 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1317 tmp
= a
, a
= b
, b
= tmp
;
1318 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1327 /* If either operand is complex, load it into a register first.
1328 The best way to do this is to copy the original insn. In this
1329 way we preserve any clobbers etc that the insn may have had.
1330 This is of course not possible in the IS_MEM case. */
1331 if (! general_operand (a
, GET_MODE (a
)))
1336 goto end_seq_and_fail
;
1340 tmp
= gen_reg_rtx (GET_MODE (a
));
1341 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1344 goto end_seq_and_fail
;
1347 a
= gen_reg_rtx (GET_MODE (a
));
1348 tmp
= copy_rtx (insn_a
);
1349 set
= single_set (tmp
);
1351 tmp
= emit_insn (PATTERN (tmp
));
1353 if (recog_memoized (tmp
) < 0)
1354 goto end_seq_and_fail
;
1356 if (! general_operand (b
, GET_MODE (b
)))
1361 goto end_seq_and_fail
;
1365 tmp
= gen_reg_rtx (GET_MODE (b
));
1366 tmp
= gen_rtx_SET (VOIDmode
, tmp
, b
);
1369 goto end_seq_and_fail
;
1372 b
= gen_reg_rtx (GET_MODE (b
));
1373 tmp
= copy_rtx (insn_b
);
1374 set
= single_set (tmp
);
1376 tmp
= PATTERN (tmp
);
1379 /* If insn to set up A clobbers any registers B depends on, try to
1380 swap insn that sets up A with the one that sets up B. If even
1381 that doesn't help, punt. */
1382 last
= get_last_insn ();
1383 if (last
&& modified_in_p (orig_b
, last
))
1385 tmp
= emit_insn_before (tmp
, get_insns ());
1386 if (modified_in_p (orig_a
, tmp
))
1387 goto end_seq_and_fail
;
1390 tmp
= emit_insn (tmp
);
1392 if (recog_memoized (tmp
) < 0)
1393 goto end_seq_and_fail
;
1396 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1397 XEXP (if_info
->cond
, 1), a
, b
);
1400 goto end_seq_and_fail
;
1402 /* If we're handling a memory for above, emit the load now. */
1405 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1407 /* Copy over flags as appropriate. */
1408 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1409 MEM_VOLATILE_P (tmp
) = 1;
1410 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1411 MEM_IN_STRUCT_P (tmp
) = 1;
1412 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1413 MEM_SCALAR_P (tmp
) = 1;
1414 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1415 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1417 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1419 noce_emit_move_insn (if_info
->x
, tmp
);
1421 else if (target
!= x
)
1422 noce_emit_move_insn (x
, target
);
1424 tmp
= end_ifcvt_sequence (if_info
);
1428 emit_insn_before_setloc (tmp
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1436 /* For most cases, the simplified condition we found is the best
1437 choice, but this is not the case for the min/max/abs transforms.
1438 For these we wish to know that it is A or B in the condition. */
1441 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1444 rtx cond
, set
, insn
;
1447 /* If target is already mentioned in the known condition, return it. */
1448 if (reg_mentioned_p (target
, if_info
->cond
))
1450 *earliest
= if_info
->cond_earliest
;
1451 return if_info
->cond
;
1454 set
= pc_set (if_info
->jump
);
1455 cond
= XEXP (SET_SRC (set
), 0);
1457 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1458 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1460 /* If we're looking for a constant, try to make the conditional
1461 have that constant in it. There are two reasons why it may
1462 not have the constant we want:
1464 1. GCC may have needed to put the constant in a register, because
1465 the target can't compare directly against that constant. For
1466 this case, we look for a SET immediately before the comparison
1467 that puts a constant in that register.
1469 2. GCC may have canonicalized the conditional, for example
1470 replacing "if x < 4" with "if x <= 3". We can undo that (or
1471 make equivalent types of changes) to get the constants we need
1472 if they're off by one in the right direction. */
1474 if (GET_CODE (target
) == CONST_INT
)
1476 enum rtx_code code
= GET_CODE (if_info
->cond
);
1477 rtx op_a
= XEXP (if_info
->cond
, 0);
1478 rtx op_b
= XEXP (if_info
->cond
, 1);
1481 /* First, look to see if we put a constant in a register. */
1482 prev_insn
= PREV_INSN (if_info
->cond_earliest
);
1484 && INSN_P (prev_insn
)
1485 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1487 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1489 src
= SET_SRC (PATTERN (prev_insn
));
1490 if (GET_CODE (src
) == CONST_INT
)
1492 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1494 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1497 if (GET_CODE (op_a
) == CONST_INT
)
1502 code
= swap_condition (code
);
1507 /* Now, look to see if we can get the right constant by
1508 adjusting the conditional. */
1509 if (GET_CODE (op_b
) == CONST_INT
)
1511 HOST_WIDE_INT desired_val
= INTVAL (target
);
1512 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1517 if (actual_val
== desired_val
+ 1)
1520 op_b
= GEN_INT (desired_val
);
1524 if (actual_val
== desired_val
- 1)
1527 op_b
= GEN_INT (desired_val
);
1531 if (actual_val
== desired_val
- 1)
1534 op_b
= GEN_INT (desired_val
);
1538 if (actual_val
== desired_val
+ 1)
1541 op_b
= GEN_INT (desired_val
);
1549 /* If we made any changes, generate a new conditional that is
1550 equivalent to what we started with, but has the right
1552 if (code
!= GET_CODE (if_info
->cond
)
1553 || op_a
!= XEXP (if_info
->cond
, 0)
1554 || op_b
!= XEXP (if_info
->cond
, 1))
1556 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1557 *earliest
= if_info
->cond_earliest
;
1562 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1563 earliest
, target
, false, true);
1564 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1567 /* We almost certainly searched back to a different place.
1568 Need to re-verify correct lifetimes. */
1570 /* X may not be mentioned in the range (cond_earliest, jump]. */
1571 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1572 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1575 /* A and B may not be modified in the range [cond_earliest, jump). */
1576 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1578 && (modified_in_p (if_info
->a
, insn
)
1579 || modified_in_p (if_info
->b
, insn
)))
1585 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1588 noce_try_minmax (struct noce_if_info
*if_info
)
1590 rtx cond
, earliest
, target
, seq
;
1591 enum rtx_code code
, op
;
1594 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1598 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1599 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1600 to get the target to tell us... */
1601 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1602 || HONOR_NANS (GET_MODE (if_info
->x
)))
1605 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1609 /* Verify the condition is of the form we expect, and canonicalize
1610 the comparison code. */
1611 code
= GET_CODE (cond
);
1612 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1614 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1617 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1619 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1621 code
= swap_condition (code
);
1626 /* Determine what sort of operation this is. Note that the code is for
1627 a taken branch, so the code->operation mapping appears backwards. */
1660 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1661 if_info
->a
, if_info
->b
,
1662 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1668 if (target
!= if_info
->x
)
1669 noce_emit_move_insn (if_info
->x
, target
);
1671 seq
= end_ifcvt_sequence (if_info
);
1675 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1676 if_info
->cond
= cond
;
1677 if_info
->cond_earliest
= earliest
;
1682 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1685 noce_try_abs (struct noce_if_info
*if_info
)
1687 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1690 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1694 /* Recognize A and B as constituting an ABS or NABS. */
1697 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1699 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1701 c
= a
; a
= b
; b
= c
;
1707 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1711 /* Verify the condition is of the form we expect. */
1712 if (rtx_equal_p (XEXP (cond
, 0), b
))
1714 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1719 /* Verify that C is zero. Search backward through the block for
1720 a REG_EQUAL note if necessary. */
1723 rtx insn
, note
= NULL
;
1724 for (insn
= earliest
;
1725 insn
!= BB_HEAD (if_info
->test_bb
);
1726 insn
= PREV_INSN (insn
))
1728 && ((note
= find_reg_note (insn
, REG_EQUAL
, c
))
1729 || (note
= find_reg_note (insn
, REG_EQUIV
, c
))))
1736 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
1737 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
1738 c
= get_pool_constant (XEXP (c
, 0));
1740 /* Work around funny ideas get_condition has wrt canonicalization.
1741 Note that these rtx constants are known to be CONST_INT, and
1742 therefore imply integer comparisons. */
1743 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
1745 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
1747 else if (c
!= CONST0_RTX (GET_MODE (b
)))
1750 /* Determine what sort of operation this is. */
1751 switch (GET_CODE (cond
))
1770 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
1772 /* ??? It's a quandary whether cmove would be better here, especially
1773 for integers. Perhaps combine will clean things up. */
1774 if (target
&& negate
)
1775 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
, if_info
->x
, 0);
1783 if (target
!= if_info
->x
)
1784 noce_emit_move_insn (if_info
->x
, target
);
1786 seq
= end_ifcvt_sequence (if_info
);
1790 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1791 if_info
->cond
= cond
;
1792 if_info
->cond_earliest
= earliest
;
1797 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
1800 noce_try_sign_mask (struct noce_if_info
*if_info
)
1802 rtx cond
, t
, m
, c
, seq
;
1803 enum machine_mode mode
;
1809 cond
= if_info
->cond
;
1810 code
= GET_CODE (cond
);
1815 if (if_info
->a
== const0_rtx
)
1817 if ((code
== LT
&& c
== const0_rtx
)
1818 || (code
== LE
&& c
== constm1_rtx
))
1821 else if (if_info
->b
== const0_rtx
)
1823 if ((code
== GE
&& c
== const0_rtx
)
1824 || (code
== GT
&& c
== constm1_rtx
))
1828 if (! t
|| side_effects_p (t
))
1831 /* We currently don't handle different modes. */
1832 mode
= GET_MODE (t
);
1833 if (GET_MODE (m
) != mode
)
1836 /* This is only profitable if T is cheap, or T is unconditionally
1837 executed/evaluated in the original insn sequence. */
1838 if (rtx_cost (t
, SET
) >= COSTS_N_INSNS (2)
1839 && (!if_info
->b_unconditional
1840 || t
!= if_info
->b
))
1844 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
1845 "(signed) m >> 31" directly. This benefits targets with specialized
1846 insns to obtain the signmask, but still uses ashr_optab otherwise. */
1847 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
1848 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
1857 noce_emit_move_insn (if_info
->x
, t
);
1859 seq
= end_ifcvt_sequence (if_info
);
1863 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1868 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
1872 noce_try_bitop (struct noce_if_info
*if_info
)
1874 rtx cond
, x
, a
, result
, seq
;
1875 enum machine_mode mode
;
1880 cond
= if_info
->cond
;
1881 code
= GET_CODE (cond
);
1883 /* Check for no else condition. */
1884 if (! rtx_equal_p (x
, if_info
->b
))
1887 /* Check for a suitable condition. */
1888 if (code
!= NE
&& code
!= EQ
)
1890 if (XEXP (cond
, 1) != const0_rtx
)
1892 cond
= XEXP (cond
, 0);
1894 /* ??? We could also handle AND here. */
1895 if (GET_CODE (cond
) == ZERO_EXTRACT
)
1897 if (XEXP (cond
, 1) != const1_rtx
1898 || GET_CODE (XEXP (cond
, 2)) != CONST_INT
1899 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
1901 bitnum
= INTVAL (XEXP (cond
, 2));
1902 mode
= GET_MODE (x
);
1903 if (bitnum
>= HOST_BITS_PER_WIDE_INT
)
1910 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
1912 /* Check for "if (X & C) x = x op C". */
1913 if (! rtx_equal_p (x
, XEXP (a
, 0))
1914 || GET_CODE (XEXP (a
, 1)) != CONST_INT
1915 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
1916 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
1919 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
1920 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
1921 if (GET_CODE (a
) == IOR
)
1922 result
= (code
== NE
) ? a
: NULL_RTX
;
1923 else if (code
== NE
)
1925 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
1926 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
1927 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
1931 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
1932 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
1933 result
= simplify_gen_binary (AND
, mode
, x
, result
);
1936 else if (GET_CODE (a
) == AND
)
1938 /* Check for "if (X & C) x &= ~C". */
1939 if (! rtx_equal_p (x
, XEXP (a
, 0))
1940 || GET_CODE (XEXP (a
, 1)) != CONST_INT
1941 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
1942 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
1945 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
1946 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
1947 result
= (code
== EQ
) ? a
: NULL_RTX
;
1955 noce_emit_move_insn (x
, result
);
1956 seq
= end_ifcvt_sequence (if_info
);
1960 emit_insn_before_setloc (seq
, if_info
->jump
,
1961 INSN_LOCATOR (if_info
->insn_a
));
1967 /* Similar to get_condition, only the resulting condition must be
1968 valid at JUMP, instead of at EARLIEST. */
1971 noce_get_condition (rtx jump
, rtx
*earliest
)
1976 if (! any_condjump_p (jump
))
1979 set
= pc_set (jump
);
1981 /* If this branches to JUMP_LABEL when the condition is false,
1982 reverse the condition. */
1983 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1984 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
1986 /* If the condition variable is a register and is MODE_INT, accept it. */
1988 cond
= XEXP (SET_SRC (set
), 0);
1989 tmp
= XEXP (cond
, 0);
1990 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
)
1995 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
1996 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2000 /* Otherwise, fall back on canonicalize_condition to do the dirty
2001 work of manipulating MODE_CC values and COMPARE rtx codes. */
2002 return canonicalize_condition (jump
, cond
, reverse
, earliest
,
2003 NULL_RTX
, false, true);
2006 /* Return true if OP is ok for if-then-else processing. */
2009 noce_operand_ok (rtx op
)
2011 /* We special-case memories, so handle any of them with
2012 no address side effects. */
2014 return ! side_effects_p (XEXP (op
, 0));
2016 if (side_effects_p (op
))
2019 return ! may_trap_p (op
);
2022 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
2023 without using conditional execution. Return TRUE if we were
2024 successful at converting the block. */
2027 noce_process_if_block (struct ce_if_block
* ce_info
)
2029 basic_block test_bb
= ce_info
->test_bb
; /* test block */
2030 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
2031 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
2032 struct noce_if_info if_info
;
2035 rtx orig_x
, x
, a
, b
;
2038 /* We're looking for patterns of the form
2040 (1) if (...) x = a; else x = b;
2041 (2) x = b; if (...) x = a;
2042 (3) if (...) x = a; // as if with an initial x = x.
2044 The later patterns require jumps to be more expensive.
2046 ??? For future expansion, look for multiple X in such patterns. */
2048 /* If test is comprised of && or || elements, don't handle it unless it is
2049 the special case of && elements without an ELSE block. */
2050 if (ce_info
->num_multiple_test_blocks
)
2052 if (else_bb
|| ! ce_info
->and_and_p
)
2055 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
2056 ce_info
->num_multiple_test_blocks
= 0;
2057 ce_info
->num_and_and_blocks
= 0;
2058 ce_info
->num_or_or_blocks
= 0;
2061 /* If this is not a standard conditional jump, we can't parse it. */
2062 jump
= BB_END (test_bb
);
2063 cond
= noce_get_condition (jump
, &if_info
.cond_earliest
);
2067 /* If the conditional jump is more than just a conditional
2068 jump, then we can not do if-conversion on this block. */
2069 if (! onlyjump_p (jump
))
2072 /* We must be comparing objects whose modes imply the size. */
2073 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
2076 /* Look for one of the potential sets. */
2077 insn_a
= first_active_insn (then_bb
);
2079 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2080 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2083 x
= SET_DEST (set_a
);
2084 a
= SET_SRC (set_a
);
2086 /* Look for the other potential set. Make sure we've got equivalent
2088 /* ??? This is overconservative. Storing to two different mems is
2089 as easy as conditionally computing the address. Storing to a
2090 single mem merely requires a scratch memory to use as one of the
2091 destination addresses; often the memory immediately below the
2092 stack pointer is available for this. */
2096 insn_b
= first_active_insn (else_bb
);
2098 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2099 || (set_b
= single_set (insn_b
)) == NULL_RTX
2100 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
2105 insn_b
= prev_nonnote_insn (if_info
.cond_earliest
);
2106 /* We're going to be moving the evaluation of B down from above
2107 COND_EARLIEST to JUMP. Make sure the relevant data is still
2110 || !NONJUMP_INSN_P (insn_b
)
2111 || (set_b
= single_set (insn_b
)) == NULL_RTX
2112 || ! rtx_equal_p (x
, SET_DEST (set_b
))
2113 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2114 || modified_between_p (SET_SRC (set_b
),
2115 PREV_INSN (if_info
.cond_earliest
), jump
)
2116 /* Likewise with X. In particular this can happen when
2117 noce_get_condition looks farther back in the instruction
2118 stream than one might expect. */
2119 || reg_overlap_mentioned_p (x
, cond
)
2120 || reg_overlap_mentioned_p (x
, a
)
2121 || modified_between_p (x
, PREV_INSN (if_info
.cond_earliest
), jump
))
2122 insn_b
= set_b
= NULL_RTX
;
2125 /* If x has side effects then only the if-then-else form is safe to
2126 convert. But even in that case we would need to restore any notes
2127 (such as REG_INC) at then end. That can be tricky if
2128 noce_emit_move_insn expands to more than one insn, so disable the
2129 optimization entirely for now if there are side effects. */
2130 if (side_effects_p (x
))
2133 /* If x is a read-only memory, then the program is valid only if we
2134 avoid the store into it. If there are stores on both the THEN and
2135 ELSE arms, then we can go ahead with the conversion; either the
2136 program is broken, or the condition is always false such that the
2137 other memory is selected. */
2138 if (!set_b
&& MEM_P (x
) && MEM_READONLY_P (x
))
2141 b
= (set_b
? SET_SRC (set_b
) : x
);
2143 /* Only operate on register destinations, and even then avoid extending
2144 the lifetime of hard registers on small register class machines. */
2147 || (SMALL_REGISTER_CLASSES
2148 && REGNO (x
) < FIRST_PSEUDO_REGISTER
))
2150 if (no_new_pseudos
|| GET_MODE (x
) == BLKmode
)
2152 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2153 ? XEXP (x
, 0) : x
));
2156 /* Don't operate on sources that may trap or are volatile. */
2157 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2160 /* Set up the info block for our subroutines. */
2161 if_info
.test_bb
= test_bb
;
2162 if_info
.cond
= cond
;
2163 if_info
.jump
= jump
;
2164 if_info
.insn_a
= insn_a
;
2165 if_info
.insn_b
= insn_b
;
2169 if_info
.b_unconditional
= else_bb
== 0;
2171 /* Try optimizations in some approximation of a useful order. */
2172 /* ??? Should first look to see if X is live incoming at all. If it
2173 isn't, we don't need anything but an unconditional set. */
2175 /* Look and see if A and B are really the same. Avoid creating silly
2176 cmove constructs that no one will fix up later. */
2177 if (rtx_equal_p (a
, b
))
2179 /* If we have an INSN_B, we don't have to create any new rtl. Just
2180 move the instruction that we already have. If we don't have an
2181 INSN_B, that means that A == X, and we've got a noop move. In
2182 that case don't do anything and let the code below delete INSN_A. */
2183 if (insn_b
&& else_bb
)
2187 if (else_bb
&& insn_b
== BB_END (else_bb
))
2188 BB_END (else_bb
) = PREV_INSN (insn_b
);
2189 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2191 /* If there was a REG_EQUAL note, delete it since it may have been
2192 true due to this insn being after a jump. */
2193 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2194 remove_note (insn_b
, note
);
2198 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2199 x must be executed twice. */
2200 else if (insn_b
&& side_effects_p (orig_x
))
2207 /* Disallow the "if (...) x = a;" form (with an implicit "else x = x;")
2208 for most optimizations if writing to x may trap, i.e. it's a memory
2209 other than a static var or a stack slot. */
2212 && ! MEM_NOTRAP_P (orig_x
)
2213 && rtx_addr_can_trap_p (XEXP (orig_x
, 0)))
2215 if (HAVE_conditional_move
)
2217 if (noce_try_cmove (&if_info
))
2219 if (! HAVE_conditional_execution
2220 && noce_try_cmove_arith (&if_info
))
2226 if (noce_try_move (&if_info
))
2228 if (noce_try_store_flag (&if_info
))
2230 if (noce_try_bitop (&if_info
))
2232 if (noce_try_minmax (&if_info
))
2234 if (noce_try_abs (&if_info
))
2236 if (HAVE_conditional_move
2237 && noce_try_cmove (&if_info
))
2239 if (! HAVE_conditional_execution
)
2241 if (noce_try_store_flag_constants (&if_info
))
2243 if (noce_try_addcc (&if_info
))
2245 if (noce_try_store_flag_mask (&if_info
))
2247 if (HAVE_conditional_move
2248 && noce_try_cmove_arith (&if_info
))
2250 if (noce_try_sign_mask (&if_info
))
2257 /* The original sets may now be killed. */
2258 delete_insn (insn_a
);
2260 /* Several special cases here: First, we may have reused insn_b above,
2261 in which case insn_b is now NULL. Second, we want to delete insn_b
2262 if it came from the ELSE block, because follows the now correct
2263 write that appears in the TEST block. However, if we got insn_b from
2264 the TEST block, it may in fact be loading data needed for the comparison.
2265 We'll let life_analysis remove the insn if it's really dead. */
2266 if (insn_b
&& else_bb
)
2267 delete_insn (insn_b
);
2269 /* The new insns will have been inserted immediately before the jump. We
2270 should be able to remove the jump with impunity, but the condition itself
2271 may have been modified by gcse to be shared across basic blocks. */
2274 /* If we used a temporary, fix it up now. */
2278 noce_emit_move_insn (orig_x
, x
);
2279 insn_b
= get_insns ();
2280 set_used_flags (orig_x
);
2281 unshare_all_rtl_in_chain (insn_b
);
2284 emit_insn_after_setloc (insn_b
, BB_END (test_bb
), INSN_LOCATOR (insn_a
));
2287 /* Merge the blocks! */
2288 merge_if_block (ce_info
);
2293 /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
2294 straight line code. Return true if successful. */
2297 process_if_block (struct ce_if_block
* ce_info
)
2299 if (! reload_completed
2300 && noce_process_if_block (ce_info
))
2303 if (HAVE_conditional_execution
&& reload_completed
)
2305 /* If we have && and || tests, try to first handle combining the && and
2306 || tests into the conditional code, and if that fails, go back and
2307 handle it without the && and ||, which at present handles the && case
2308 if there was no ELSE block. */
2309 if (cond_exec_process_if_block (ce_info
, TRUE
))
2312 if (ce_info
->num_multiple_test_blocks
)
2316 if (cond_exec_process_if_block (ce_info
, FALSE
))
2324 /* Merge the blocks and mark for local life update. */
2327 merge_if_block (struct ce_if_block
* ce_info
)
2329 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
2330 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
2331 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
2332 basic_block join_bb
= ce_info
->join_bb
; /* join block */
2333 basic_block combo_bb
;
2335 /* All block merging is done into the lower block numbers. */
2339 /* Merge any basic blocks to handle && and || subtests. Each of
2340 the blocks are on the fallthru path from the predecessor block. */
2341 if (ce_info
->num_multiple_test_blocks
> 0)
2343 basic_block bb
= test_bb
;
2344 basic_block last_test_bb
= ce_info
->last_test_bb
;
2345 basic_block fallthru
= block_fallthru (bb
);
2350 fallthru
= block_fallthru (bb
);
2351 merge_blocks (combo_bb
, bb
);
2354 while (bb
!= last_test_bb
);
2357 /* Merge TEST block into THEN block. Normally the THEN block won't have a
2358 label, but it might if there were || tests. That label's count should be
2359 zero, and it normally should be removed. */
2363 if (combo_bb
->global_live_at_end
)
2364 COPY_REG_SET (combo_bb
->global_live_at_end
,
2365 then_bb
->global_live_at_end
);
2366 merge_blocks (combo_bb
, then_bb
);
2370 /* The ELSE block, if it existed, had a label. That label count
2371 will almost always be zero, but odd things can happen when labels
2372 get their addresses taken. */
2375 merge_blocks (combo_bb
, else_bb
);
2379 /* If there was no join block reported, that means it was not adjacent
2380 to the others, and so we cannot merge them. */
2384 rtx last
= BB_END (combo_bb
);
2386 /* The outgoing edge for the current COMBO block should already
2387 be correct. Verify this. */
2388 if (EDGE_COUNT (combo_bb
->succs
) == 0)
2389 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
2390 || (NONJUMP_INSN_P (last
)
2391 && GET_CODE (PATTERN (last
)) == TRAP_IF
2392 && (TRAP_CONDITION (PATTERN (last
))
2393 == const_true_rtx
)));
2396 /* There should still be something at the end of the THEN or ELSE
2397 blocks taking us to our final destination. */
2398 gcc_assert (JUMP_P (last
)
2399 || (EDGE_SUCC (combo_bb
, 0)->dest
== EXIT_BLOCK_PTR
2401 && SIBLING_CALL_P (last
))
2402 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
2403 && can_throw_internal (last
)));
2406 /* The JOIN block may have had quite a number of other predecessors too.
2407 Since we've already merged the TEST, THEN and ELSE blocks, we should
2408 have only one remaining edge from our if-then-else diamond. If there
2409 is more than one remaining edge, it must come from elsewhere. There
2410 may be zero incoming edges if the THEN block didn't actually join
2411 back up (as with a call to a non-return function). */
2412 else if (EDGE_COUNT (join_bb
->preds
) < 2
2413 && join_bb
!= EXIT_BLOCK_PTR
)
2415 /* We can merge the JOIN. */
2416 if (combo_bb
->global_live_at_end
)
2417 COPY_REG_SET (combo_bb
->global_live_at_end
,
2418 join_bb
->global_live_at_end
);
2420 merge_blocks (combo_bb
, join_bb
);
2425 /* We cannot merge the JOIN. */
2427 /* The outgoing edge for the current COMBO block should already
2428 be correct. Verify this. */
2429 gcc_assert (single_succ_p (combo_bb
)
2430 && single_succ (combo_bb
) == join_bb
);
2432 /* Remove the jump and cruft from the end of the COMBO block. */
2433 if (join_bb
!= EXIT_BLOCK_PTR
)
2434 tidy_fallthru_edge (single_succ_edge (combo_bb
));
2437 num_updated_if_blocks
++;
2440 /* Find a block ending in a simple IF condition and try to transform it
2441 in some way. When converting a multi-block condition, put the new code
2442 in the first such block and delete the rest. Return a pointer to this
2443 first block if some transformation was done. Return NULL otherwise. */
2446 find_if_header (basic_block test_bb
, int pass
)
2448 ce_if_block_t ce_info
;
2452 /* The kind of block we're looking for has exactly two successors. */
2453 if (EDGE_COUNT (test_bb
->succs
) != 2)
2456 then_edge
= EDGE_SUCC (test_bb
, 0);
2457 else_edge
= EDGE_SUCC (test_bb
, 1);
2459 /* Neither edge should be abnormal. */
2460 if ((then_edge
->flags
& EDGE_COMPLEX
)
2461 || (else_edge
->flags
& EDGE_COMPLEX
))
2464 /* Nor exit the loop. */
2465 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
2466 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
2469 /* The THEN edge is canonically the one that falls through. */
2470 if (then_edge
->flags
& EDGE_FALLTHRU
)
2472 else if (else_edge
->flags
& EDGE_FALLTHRU
)
2475 else_edge
= then_edge
;
2479 /* Otherwise this must be a multiway branch of some sort. */
2482 memset (&ce_info
, '\0', sizeof (ce_info
));
2483 ce_info
.test_bb
= test_bb
;
2484 ce_info
.then_bb
= then_edge
->dest
;
2485 ce_info
.else_bb
= else_edge
->dest
;
2486 ce_info
.pass
= pass
;
2488 #ifdef IFCVT_INIT_EXTRA_FIELDS
2489 IFCVT_INIT_EXTRA_FIELDS (&ce_info
);
2492 if (find_if_block (&ce_info
))
2495 if (HAVE_trap
&& HAVE_conditional_trap
2496 && find_cond_trap (test_bb
, then_edge
, else_edge
))
2499 if (dom_computed
[CDI_POST_DOMINATORS
] >= DOM_NO_FAST_QUERY
2500 && (! HAVE_conditional_execution
|| reload_completed
))
2502 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
2504 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
2512 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
2513 return ce_info
.test_bb
;
2516 /* Return true if a block has two edges, one of which falls through to the next
2517 block, and the other jumps to a specific block, so that we can tell if the
2518 block is part of an && test or an || test. Returns either -1 or the number
2519 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
2522 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
2525 int fallthru_p
= FALSE
;
2532 if (!cur_bb
|| !target_bb
)
2535 /* If no edges, obviously it doesn't jump or fallthru. */
2536 if (EDGE_COUNT (cur_bb
->succs
) == 0)
2539 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
2541 if (cur_edge
->flags
& EDGE_COMPLEX
)
2542 /* Anything complex isn't what we want. */
2545 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
2548 else if (cur_edge
->dest
== target_bb
)
2555 if ((jump_p
& fallthru_p
) == 0)
2558 /* Don't allow calls in the block, since this is used to group && and ||
2559 together for conditional execution support. ??? we should support
2560 conditional execution support across calls for IA-64 some day, but
2561 for now it makes the code simpler. */
2562 end
= BB_END (cur_bb
);
2563 insn
= BB_HEAD (cur_bb
);
2565 while (insn
!= NULL_RTX
)
2572 && GET_CODE (PATTERN (insn
)) != USE
2573 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
2579 insn
= NEXT_INSN (insn
);
2585 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
2586 block. If so, we'll try to convert the insns to not require the branch.
2587 Return TRUE if we were successful at converting the block. */
2590 find_if_block (struct ce_if_block
* ce_info
)
2592 basic_block test_bb
= ce_info
->test_bb
;
2593 basic_block then_bb
= ce_info
->then_bb
;
2594 basic_block else_bb
= ce_info
->else_bb
;
2595 basic_block join_bb
= NULL_BLOCK
;
2600 ce_info
->last_test_bb
= test_bb
;
2602 /* Discover if any fall through predecessors of the current test basic block
2603 were && tests (which jump to the else block) or || tests (which jump to
2605 if (HAVE_conditional_execution
&& reload_completed
2606 && single_pred_p (test_bb
)
2607 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
2609 basic_block bb
= single_pred (test_bb
);
2610 basic_block target_bb
;
2611 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
2614 /* Determine if the preceding block is an && or || block. */
2615 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
2617 ce_info
->and_and_p
= TRUE
;
2618 target_bb
= else_bb
;
2620 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
2622 ce_info
->and_and_p
= FALSE
;
2623 target_bb
= then_bb
;
2626 target_bb
= NULL_BLOCK
;
2628 if (target_bb
&& n_insns
<= max_insns
)
2630 int total_insns
= 0;
2633 ce_info
->last_test_bb
= test_bb
;
2635 /* Found at least one && or || block, look for more. */
2638 ce_info
->test_bb
= test_bb
= bb
;
2639 total_insns
+= n_insns
;
2642 if (!single_pred_p (bb
))
2645 bb
= single_pred (bb
);
2646 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
2648 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
2650 ce_info
->num_multiple_test_blocks
= blocks
;
2651 ce_info
->num_multiple_test_insns
= total_insns
;
2653 if (ce_info
->and_and_p
)
2654 ce_info
->num_and_and_blocks
= blocks
;
2656 ce_info
->num_or_or_blocks
= blocks
;
2660 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
2661 other than any || blocks which jump to the THEN block. */
2662 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
2665 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
2666 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
2668 if (cur_edge
->flags
& EDGE_COMPLEX
)
2672 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
2674 if (cur_edge
->flags
& EDGE_COMPLEX
)
2678 /* The THEN block of an IF-THEN combo must have zero or one successors. */
2679 if (EDGE_COUNT (then_bb
->succs
) > 0
2680 && (!single_succ_p (then_bb
)
2681 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
2682 || (flow2_completed
&& tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
2685 /* If the THEN block has no successors, conditional execution can still
2686 make a conditional call. Don't do this unless the ELSE block has
2687 only one incoming edge -- the CFG manipulation is too ugly otherwise.
2688 Check for the last insn of the THEN block being an indirect jump, which
2689 is listed as not having any successors, but confuses the rest of the CE
2690 code processing. ??? we should fix this in the future. */
2691 if (EDGE_COUNT (then_bb
->succs
) == 0)
2693 if (single_pred_p (else_bb
))
2695 rtx last_insn
= BB_END (then_bb
);
2698 && NOTE_P (last_insn
)
2699 && last_insn
!= BB_HEAD (then_bb
))
2700 last_insn
= PREV_INSN (last_insn
);
2703 && JUMP_P (last_insn
)
2704 && ! simplejump_p (last_insn
))
2708 else_bb
= NULL_BLOCK
;
2714 /* If the THEN block's successor is the other edge out of the TEST block,
2715 then we have an IF-THEN combo without an ELSE. */
2716 else if (single_succ (then_bb
) == else_bb
)
2719 else_bb
= NULL_BLOCK
;
2722 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
2723 has exactly one predecessor and one successor, and the outgoing edge
2724 is not complex, then we have an IF-THEN-ELSE combo. */
2725 else if (single_succ_p (else_bb
)
2726 && single_succ (then_bb
) == single_succ (else_bb
)
2727 && single_pred_p (else_bb
)
2728 && ! (single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
2729 && ! (flow2_completed
&& tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
2730 join_bb
= single_succ (else_bb
);
2732 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
2736 num_possible_if_blocks
++;
2741 "\nIF-THEN%s block found, pass %d, start block %d "
2742 "[insn %d], then %d [%d]",
2743 (else_bb
) ? "-ELSE" : "",
2746 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
2748 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
2751 fprintf (dump_file
, ", else %d [%d]",
2753 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
2755 fprintf (dump_file
, ", join %d [%d]",
2757 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
2759 if (ce_info
->num_multiple_test_blocks
> 0)
2760 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
2761 ce_info
->num_multiple_test_blocks
,
2762 (ce_info
->and_and_p
) ? "&&" : "||",
2763 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
2764 ce_info
->last_test_bb
->index
,
2765 ((BB_HEAD (ce_info
->last_test_bb
))
2766 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
2769 fputc ('\n', dump_file
);
2772 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
2773 first condition for free, since we've already asserted that there's a
2774 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
2775 we checked the FALLTHRU flag, those are already adjacent to the last IF
2777 /* ??? As an enhancement, move the ELSE block. Have to deal with
2778 BLOCK notes, if by no other means than backing out the merge if they
2779 exist. Sticky enough I don't want to think about it now. */
2781 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
2783 if ((next
= next
->next_bb
) != join_bb
&& join_bb
!= EXIT_BLOCK_PTR
)
2791 /* Do the real work. */
2792 ce_info
->else_bb
= else_bb
;
2793 ce_info
->join_bb
= join_bb
;
2795 return process_if_block (ce_info
);
2798 /* Convert a branch over a trap, or a branch
2799 to a trap, into a conditional trap. */
2802 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
2804 basic_block then_bb
= then_edge
->dest
;
2805 basic_block else_bb
= else_edge
->dest
;
2806 basic_block other_bb
, trap_bb
;
2807 rtx trap
, jump
, cond
, cond_earliest
, seq
;
2810 /* Locate the block with the trap instruction. */
2811 /* ??? While we look for no successors, we really ought to allow
2812 EH successors. Need to fix merge_if_block for that to work. */
2813 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
2814 trap_bb
= then_bb
, other_bb
= else_bb
;
2815 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
2816 trap_bb
= else_bb
, other_bb
= then_bb
;
2822 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
2823 test_bb
->index
, trap_bb
->index
);
2826 /* If this is not a standard conditional jump, we can't parse it. */
2827 jump
= BB_END (test_bb
);
2828 cond
= noce_get_condition (jump
, &cond_earliest
);
2832 /* If the conditional jump is more than just a conditional jump, then
2833 we can not do if-conversion on this block. */
2834 if (! onlyjump_p (jump
))
2837 /* We must be comparing objects whose modes imply the size. */
2838 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
2841 /* Reverse the comparison code, if necessary. */
2842 code
= GET_CODE (cond
);
2843 if (then_bb
== trap_bb
)
2845 code
= reversed_comparison_code (cond
, jump
);
2846 if (code
== UNKNOWN
)
2850 /* Attempt to generate the conditional trap. */
2851 seq
= gen_cond_trap (code
, XEXP (cond
, 0),
2853 TRAP_CODE (PATTERN (trap
)));
2859 /* Emit the new insns before cond_earliest. */
2860 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATOR (trap
));
2862 /* Delete the trap block if possible. */
2863 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
2864 if (EDGE_COUNT (trap_bb
->preds
) == 0)
2865 delete_basic_block (trap_bb
);
2867 /* If the non-trap block and the test are now adjacent, merge them.
2868 Otherwise we must insert a direct branch. */
2869 if (test_bb
->next_bb
== other_bb
)
2871 struct ce_if_block new_ce_info
;
2873 memset (&new_ce_info
, '\0', sizeof (new_ce_info
));
2874 new_ce_info
.test_bb
= test_bb
;
2875 new_ce_info
.then_bb
= NULL
;
2876 new_ce_info
.else_bb
= NULL
;
2877 new_ce_info
.join_bb
= other_bb
;
2878 merge_if_block (&new_ce_info
);
2884 lab
= JUMP_LABEL (jump
);
2885 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
2886 LABEL_NUSES (lab
) += 1;
2887 JUMP_LABEL (newjump
) = lab
;
2888 emit_barrier_after (newjump
);
2896 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
2900 block_has_only_trap (basic_block bb
)
2904 /* We're not the exit block. */
2905 if (bb
== EXIT_BLOCK_PTR
)
2908 /* The block must have no successors. */
2909 if (EDGE_COUNT (bb
->succs
) > 0)
2912 /* The only instruction in the THEN block must be the trap. */
2913 trap
= first_active_insn (bb
);
2914 if (! (trap
== BB_END (bb
)
2915 && GET_CODE (PATTERN (trap
)) == TRAP_IF
2916 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
2922 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
2923 transformable, but not necessarily the other. There need be no
2926 Return TRUE if we were successful at converting the block.
2928 Cases we'd like to look at:
2931 if (test) goto over; // x not live
2939 if (! test) goto label;
2942 if (test) goto E; // x not live
2956 (3) // This one's really only interesting for targets that can do
2957 // multiway branching, e.g. IA-64 BBB bundles. For other targets
2958 // it results in multiple branches on a cache line, which often
2959 // does not sit well with predictors.
2961 if (test1) goto E; // predicted not taken
2977 (A) Don't do (2) if the branch is predicted against the block we're
2978 eliminating. Do it anyway if we can eliminate a branch; this requires
2979 that the sole successor of the eliminated block postdominate the other
2982 (B) With CE, on (3) we can steal from both sides of the if, creating
2991 Again, this is most useful if J postdominates.
2993 (C) CE substitutes for helpful life information.
2995 (D) These heuristics need a lot of work. */
2997 /* Tests for case 1 above. */
3000 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3002 basic_block then_bb
= then_edge
->dest
;
3003 basic_block else_bb
= else_edge
->dest
, new_bb
;
3006 /* If we are partitioning hot/cold basic blocks, we don't want to
3007 mess up unconditional or indirect jumps that cross between hot
3010 Basic block partitioning may result in some jumps that appear to
3011 be optimizable (or blocks that appear to be mergeable), but which really
3012 must be left untouched (they are required to make it safely across
3013 partition boundaries). See the comments at the top of
3014 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3016 if ((BB_END (then_bb
)
3017 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3018 || (BB_END (test_bb
)
3019 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3020 || (BB_END (else_bb
)
3021 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3025 /* THEN has one successor. */
3026 if (!single_succ_p (then_bb
))
3029 /* THEN does not fall through, but is not strange either. */
3030 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
3033 /* THEN has one predecessor. */
3034 if (!single_pred_p (then_bb
))
3037 /* THEN must do something. */
3038 if (forwarder_block_p (then_bb
))
3041 num_possible_if_blocks
++;
3044 "\nIF-CASE-1 found, start %d, then %d\n",
3045 test_bb
->index
, then_bb
->index
);
3047 /* THEN is small. */
3048 if (! cheap_bb_rtx_cost_p (then_bb
, COSTS_N_INSNS (BRANCH_COST
)))
3051 /* Registers set are dead, or are predicable. */
3052 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
3053 single_succ (then_bb
), 1))
3056 /* Conversion went ok, including moving the insns and fixing up the
3057 jump. Adjust the CFG to match. */
3059 bitmap_ior (test_bb
->global_live_at_end
,
3060 else_bb
->global_live_at_start
,
3061 then_bb
->global_live_at_end
);
3064 /* We can avoid creating a new basic block if then_bb is immediately
3065 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3068 if (then_bb
->next_bb
== else_bb
3069 && then_bb
->prev_bb
== test_bb
3070 && else_bb
!= EXIT_BLOCK_PTR
)
3072 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
3076 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
3079 then_bb_index
= then_bb
->index
;
3080 delete_basic_block (then_bb
);
3082 /* Make rest of code believe that the newly created block is the THEN_BB
3083 block we removed. */
3086 new_bb
->index
= then_bb_index
;
3087 BASIC_BLOCK (then_bb_index
) = new_bb
;
3088 /* Since the fallthru edge was redirected from test_bb to new_bb,
3089 we need to ensure that new_bb is in the same partition as
3090 test bb (you can not fall through across section boundaries). */
3091 BB_COPY_PARTITION (new_bb
, test_bb
);
3093 /* We've possibly created jump to next insn, cleanup_cfg will solve that
3097 num_updated_if_blocks
++;
3102 /* Test for case 2 above. */
3105 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3107 basic_block then_bb
= then_edge
->dest
;
3108 basic_block else_bb
= else_edge
->dest
;
3112 /* If we are partitioning hot/cold basic blocks, we don't want to
3113 mess up unconditional or indirect jumps that cross between hot
3116 Basic block partitioning may result in some jumps that appear to
3117 be optimizable (or blocks that appear to be mergeable), but which really
3118 must be left untouched (they are required to make it safely across
3119 partition boundaries). See the comments at the top of
3120 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3122 if ((BB_END (then_bb
)
3123 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3124 || (BB_END (test_bb
)
3125 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3126 || (BB_END (else_bb
)
3127 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3131 /* ELSE has one successor. */
3132 if (!single_succ_p (else_bb
))
3135 else_succ
= single_succ_edge (else_bb
);
3137 /* ELSE outgoing edge is not complex. */
3138 if (else_succ
->flags
& EDGE_COMPLEX
)
3141 /* ELSE has one predecessor. */
3142 if (!single_pred_p (else_bb
))
3145 /* THEN is not EXIT. */
3146 if (then_bb
->index
< 0)
3149 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
3150 note
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
3151 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
3153 else if (else_succ
->dest
->index
< 0
3154 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
3160 num_possible_if_blocks
++;
3163 "\nIF-CASE-2 found, start %d, else %d\n",
3164 test_bb
->index
, else_bb
->index
);
3166 /* ELSE is small. */
3167 if (! cheap_bb_rtx_cost_p (else_bb
, COSTS_N_INSNS (BRANCH_COST
)))
3170 /* Registers set are dead, or are predicable. */
3171 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
3174 /* Conversion went ok, including moving the insns and fixing up the
3175 jump. Adjust the CFG to match. */
3177 bitmap_ior (test_bb
->global_live_at_end
,
3178 then_bb
->global_live_at_start
,
3179 else_bb
->global_live_at_end
);
3181 delete_basic_block (else_bb
);
3184 num_updated_if_blocks
++;
3186 /* ??? We may now fallthru from one of THEN's successors into a join
3187 block. Rerun cleanup_cfg? Examine things manually? Wait? */
3192 /* A subroutine of dead_or_predicable called through for_each_rtx.
3193 Return 1 if a memory is found. */
3196 find_memory (rtx
*px
, void *data ATTRIBUTE_UNUSED
)
3201 /* Used by the code above to perform the actual rtl transformations.
3202 Return TRUE if successful.
3204 TEST_BB is the block containing the conditional branch. MERGE_BB
3205 is the block containing the code to manipulate. NEW_DEST is the
3206 label TEST_BB should be branching to after the conversion.
3207 REVERSEP is true if the sense of the branch should be reversed. */
3210 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
3211 basic_block other_bb
, basic_block new_dest
, int reversep
)
3213 rtx head
, end
, jump
, earliest
= NULL_RTX
, old_dest
, new_label
= NULL_RTX
;
3215 jump
= BB_END (test_bb
);
3217 /* Find the extent of the real code in the merge block. */
3218 head
= BB_HEAD (merge_bb
);
3219 end
= BB_END (merge_bb
);
3222 head
= NEXT_INSN (head
);
3227 head
= end
= NULL_RTX
;
3230 head
= NEXT_INSN (head
);
3237 head
= end
= NULL_RTX
;
3240 end
= PREV_INSN (end
);
3243 /* Disable handling dead code by conditional execution if the machine needs
3244 to do anything funny with the tests, etc. */
3245 #ifndef IFCVT_MODIFY_TESTS
3246 if (HAVE_conditional_execution
)
3248 /* In the conditional execution case, we have things easy. We know
3249 the condition is reversible. We don't have to check life info
3250 because we're going to conditionally execute the code anyway.
3251 All that's left is making sure the insns involved can actually
3256 cond
= cond_exec_get_condition (jump
);
3260 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
3262 prob_val
= XEXP (prob_val
, 0);
3266 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
3269 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
3272 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
3275 if (! cond_exec_process_insns ((ce_if_block_t
*)0, head
, end
, cond
,
3284 /* In the non-conditional execution case, we have to verify that there
3285 are no trapping operations, no calls, no references to memory, and
3286 that any registers modified are dead at the branch site. */
3288 rtx insn
, cond
, prev
;
3289 regset merge_set
, tmp
, test_live
, test_set
;
3290 struct propagate_block_info
*pbi
;
3291 unsigned i
, fail
= 0;
3294 /* Check for no calls or trapping operations. */
3295 for (insn
= head
; ; insn
= NEXT_INSN (insn
))
3301 if (may_trap_p (PATTERN (insn
)))
3304 /* ??? Even non-trapping memories such as stack frame
3305 references must be avoided. For stores, we collect
3306 no lifetime info; for reads, we'd have to assert
3307 true_dependence false against every store in the
3309 if (for_each_rtx (&PATTERN (insn
), find_memory
, NULL
))
3316 if (! any_condjump_p (jump
))
3319 /* Find the extent of the conditional. */
3320 cond
= noce_get_condition (jump
, &earliest
);
3325 MERGE_SET = set of registers set in MERGE_BB
3326 TEST_LIVE = set of registers live at EARLIEST
3327 TEST_SET = set of registers set between EARLIEST and the
3328 end of the block. */
3330 tmp
= ALLOC_REG_SET (®_obstack
);
3331 merge_set
= ALLOC_REG_SET (®_obstack
);
3332 test_live
= ALLOC_REG_SET (®_obstack
);
3333 test_set
= ALLOC_REG_SET (®_obstack
);
3335 /* ??? bb->local_set is only valid during calculate_global_regs_live,
3336 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
3337 since we've already asserted that MERGE_BB is small. */
3338 propagate_block (merge_bb
, tmp
, merge_set
, merge_set
, 0);
3340 /* For small register class machines, don't lengthen lifetimes of
3341 hard registers before reload. */
3342 if (SMALL_REGISTER_CLASSES
&& ! reload_completed
)
3344 EXECUTE_IF_SET_IN_BITMAP (merge_set
, 0, i
, bi
)
3346 if (i
< FIRST_PSEUDO_REGISTER
3348 && ! global_regs
[i
])
3353 /* For TEST, we're interested in a range of insns, not a whole block.
3354 Moreover, we're interested in the insns live from OTHER_BB. */
3356 COPY_REG_SET (test_live
, other_bb
->global_live_at_start
);
3357 pbi
= init_propagate_block_info (test_bb
, test_live
, test_set
, test_set
,
3360 for (insn
= jump
; ; insn
= prev
)
3362 prev
= propagate_one_insn (pbi
, insn
);
3363 if (insn
== earliest
)
3367 free_propagate_block_info (pbi
);
3369 /* We can perform the transformation if
3370 MERGE_SET & (TEST_SET | TEST_LIVE)
3372 TEST_SET & merge_bb->global_live_at_start
3375 if (bitmap_intersect_p (test_set
, merge_set
)
3376 || bitmap_intersect_p (test_live
, merge_set
)
3377 || bitmap_intersect_p (test_set
, merge_bb
->global_live_at_start
))
3381 FREE_REG_SET (merge_set
);
3382 FREE_REG_SET (test_live
);
3383 FREE_REG_SET (test_set
);
3390 /* We don't want to use normal invert_jump or redirect_jump because
3391 we don't want to delete_insn called. Also, we want to do our own
3392 change group management. */
3394 old_dest
= JUMP_LABEL (jump
);
3395 if (other_bb
!= new_dest
)
3397 new_label
= block_label (new_dest
);
3399 ? ! invert_jump_1 (jump
, new_label
)
3400 : ! redirect_jump_1 (jump
, new_label
))
3404 if (! apply_change_group ())
3407 if (other_bb
!= new_dest
)
3409 redirect_jump_2 (jump
, old_dest
, new_label
, -1, reversep
);
3411 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
3414 gcov_type count
, probability
;
3415 count
= BRANCH_EDGE (test_bb
)->count
;
3416 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
3417 FALLTHRU_EDGE (test_bb
)->count
= count
;
3418 probability
= BRANCH_EDGE (test_bb
)->probability
;
3419 BRANCH_EDGE (test_bb
)->probability
3420 = FALLTHRU_EDGE (test_bb
)->probability
;
3421 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
3422 update_br_prob_note (test_bb
);
3426 /* Move the insns out of MERGE_BB to before the branch. */
3429 if (end
== BB_END (merge_bb
))
3430 BB_END (merge_bb
) = PREV_INSN (head
);
3432 if (squeeze_notes (&head
, &end
))
3435 reorder_insns (head
, end
, PREV_INSN (earliest
));
3438 /* Remove the jump and edge if we can. */
3439 if (other_bb
== new_dest
)
3442 remove_edge (BRANCH_EDGE (test_bb
));
3443 /* ??? Can't merge blocks here, as then_bb is still in use.
3444 At minimum, the merge will get done just before bb-reorder. */
3454 /* Main entry point for all if-conversion. */
3457 if_convert (int x_life_data_ok
)
3462 num_possible_if_blocks
= 0;
3463 num_updated_if_blocks
= 0;
3464 num_true_changes
= 0;
3465 life_data_ok
= (x_life_data_ok
!= 0);
3467 if ((! targetm
.cannot_modify_jumps_p ())
3468 && (!flag_reorder_blocks_and_partition
|| !no_new_pseudos
3469 || !targetm
.have_named_sections
))
3473 flow_loops_find (&loops
);
3474 mark_loop_exit_edges (&loops
);
3475 flow_loops_free (&loops
);
3476 free_dominance_info (CDI_DOMINATORS
);
3479 /* Compute postdominators if we think we'll use them. */
3480 if (HAVE_conditional_execution
|| life_data_ok
)
3481 calculate_dominance_info (CDI_POST_DOMINATORS
);
3486 /* Go through each of the basic blocks looking for things to convert. If we
3487 have conditional execution, we make multiple passes to allow us to handle
3488 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
3492 cond_exec_changed_p
= FALSE
;
3495 #ifdef IFCVT_MULTIPLE_DUMPS
3496 if (dump_file
&& pass
> 1)
3497 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
3503 while ((new_bb
= find_if_header (bb
, pass
)))
3507 #ifdef IFCVT_MULTIPLE_DUMPS
3508 if (dump_file
&& cond_exec_changed_p
)
3509 print_rtl_with_bb (dump_file
, get_insns ());
3512 while (cond_exec_changed_p
);
3514 #ifdef IFCVT_MULTIPLE_DUMPS
3516 fprintf (dump_file
, "\n\n========== no more changes\n");
3519 free_dominance_info (CDI_POST_DOMINATORS
);
3524 clear_aux_for_blocks ();
3526 /* Rebuild life info for basic blocks that require it. */
3527 if (num_true_changes
&& life_data_ok
)
3529 /* If we allocated new pseudos, we must resize the array for sched1. */
3530 if (max_regno
< max_reg_num ())
3532 max_regno
= max_reg_num ();
3533 allocate_reg_info (max_regno
, FALSE
, FALSE
);
3535 update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES
,
3536 PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
3537 | PROP_KILL_DEAD_CODE
);
3540 /* Write the final stats. */
3541 if (dump_file
&& num_possible_if_blocks
> 0)
3544 "\n%d possible IF blocks searched.\n",
3545 num_possible_if_blocks
);
3547 "%d IF blocks converted.\n",
3548 num_updated_if_blocks
);
3550 "%d true changes made.\n\n\n",
3554 #ifdef ENABLE_CHECKING
3555 verify_flow_info ();