1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it 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 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
22 /* This is the jump-optimization pass of the compiler.
23 It is run two or three times: once before cse, sometimes once after cse,
24 and once after reload (before final).
26 jump_optimize deletes unreachable code and labels that are not used.
27 It also deletes jumps that jump to the following insn,
28 and simplifies jumps around unconditional jumps and jumps
29 to unconditional jumps.
31 Each CODE_LABEL has a count of the times it is used
32 stored in the LABEL_NUSES internal field, and each JUMP_INSN
33 has one label that it refers to stored in the
34 JUMP_LABEL internal field. With this we can detect labels that
35 become unused because of the deletion of all the jumps that
36 formerly used them. The JUMP_LABEL info is sometimes looked
39 Optionally, cross-jumping can be done. Currently it is done
40 only the last time (when after reload and before final).
41 In fact, the code for cross-jumping now assumes that register
42 allocation has been done, since it uses `rtx_renumbered_equal_p'.
44 Jump optimization is done after cse when cse's constant-propagation
45 causes jumps to become unconditional or to be deleted.
47 Unreachable loops are not detected here, because the labels
48 have references and the insns appear reachable from the labels.
49 find_basic_blocks in flow.c finds and deletes such loops.
51 The subroutines delete_insn, redirect_jump, and invert_jump are used
52 from other passes as well. */
59 #include "hard-reg-set.h"
61 #include "insn-config.h"
62 #include "insn-attr.h"
70 /* ??? Eventually must record somehow the labels used by jumps
71 from nested functions. */
72 /* Pre-record the next or previous real insn for each label?
73 No, this pass is very fast anyway. */
74 /* Condense consecutive labels?
75 This would make life analysis faster, maybe. */
76 /* Optimize jump y; x: ... y: jumpif... x?
77 Don't know if it is worth bothering with. */
78 /* Optimize two cases of conditional jump to conditional jump?
79 This can never delete any instruction or make anything dead,
80 or even change what is live at any point.
81 So perhaps let combiner do it. */
83 /* Vector indexed by uid.
84 For each CODE_LABEL, index by its uid to get first unconditional jump
85 that jumps to the label.
86 For each JUMP_INSN, index by its uid to get the next unconditional jump
87 that jumps to the same label.
88 Element 0 is the start of a chain of all return insns.
89 (It is safe to use element 0 because insn uid 0 is not used. */
91 static rtx
*jump_chain
;
93 /* Maximum index in jump_chain. */
95 static int max_jump_chain
;
97 /* Indicates whether death notes are significant in cross jump analysis.
98 Normally they are not significant, because of A and B jump to C,
99 and R dies in A, it must die in B. But this might not be true after
100 stack register conversion, and we must compare death notes in that
103 static int cross_jump_death_matters
= 0;
105 static int init_label_info
PARAMS ((rtx
));
106 static void delete_barrier_successors
PARAMS ((rtx
));
107 static void mark_all_labels
PARAMS ((rtx
, int));
108 static rtx delete_unreferenced_labels
PARAMS ((rtx
));
109 static void delete_noop_moves
PARAMS ((rtx
));
110 static int duplicate_loop_exit_test
PARAMS ((rtx
));
111 static void find_cross_jump
PARAMS ((rtx
, rtx
, int, rtx
*, rtx
*));
112 static void do_cross_jump
PARAMS ((rtx
, rtx
, rtx
));
113 static int jump_back_p
PARAMS ((rtx
, rtx
));
114 static int tension_vector_labels
PARAMS ((rtx
, int));
115 static void delete_computation
PARAMS ((rtx
));
116 static void redirect_exp_1
PARAMS ((rtx
*, rtx
, rtx
, rtx
));
117 static int redirect_exp
PARAMS ((rtx
, rtx
, rtx
));
118 static void invert_exp_1
PARAMS ((rtx
));
119 static int invert_exp
PARAMS ((rtx
));
120 static void delete_from_jump_chain
PARAMS ((rtx
));
121 static int delete_labelref_insn
PARAMS ((rtx
, rtx
, int));
122 static void mark_modified_reg
PARAMS ((rtx
, rtx
, void *));
123 static void redirect_tablejump
PARAMS ((rtx
, rtx
));
124 static void jump_optimize_1
PARAMS ((rtx
, int, int, int, int, int));
125 static int returnjump_p_1
PARAMS ((rtx
*, void *));
126 static void delete_prior_computation
PARAMS ((rtx
, rtx
));
128 /* Main external entry point into the jump optimizer. See comments before
129 jump_optimize_1 for descriptions of the arguments. */
131 jump_optimize (f
, cross_jump
, noop_moves
, after_regscan
)
137 jump_optimize_1 (f
, cross_jump
, noop_moves
, after_regscan
, 0, 0);
140 /* Alternate entry into the jump optimizer. This entry point only rebuilds
141 the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
144 rebuild_jump_labels (f
)
147 jump_optimize_1 (f
, 0, 0, 0, 1, 0);
150 /* Alternate entry into the jump optimizer. Do only trivial optimizations. */
153 jump_optimize_minimal (f
)
156 jump_optimize_1 (f
, 0, 0, 0, 0, 1);
159 /* Delete no-op jumps and optimize jumps to jumps
160 and jumps around jumps.
161 Delete unused labels and unreachable code.
163 If CROSS_JUMP is 1, detect matching code
164 before a jump and its destination and unify them.
165 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
167 If NOOP_MOVES is nonzero, delete no-op move insns.
169 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
170 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
172 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
173 and JUMP_LABEL field for jumping insns.
175 If `optimize' is zero, don't change any code,
176 just determine whether control drops off the end of the function.
177 This case occurs when we have -W and not -O.
178 It works because `delete_insn' checks the value of `optimize'
179 and refrains from actually deleting when that is 0.
181 If MINIMAL is nonzero, then we only perform trivial optimizations:
183 * Removal of unreachable code after BARRIERs.
184 * Removal of unreferenced CODE_LABELs.
185 * Removal of a jump to the next instruction.
186 * Removal of a conditional jump followed by an unconditional jump
187 to the same target as the conditional jump.
188 * Simplify a conditional jump around an unconditional jump.
189 * Simplify a jump to a jump.
190 * Delete extraneous line number notes.
194 jump_optimize_1 (f
, cross_jump
, noop_moves
, after_regscan
,
195 mark_labels_only
, minimal
)
200 int mark_labels_only
;
203 register rtx insn
, next
;
209 enum rtx_code reversed_code
;
211 cross_jump_death_matters
= (cross_jump
== 2);
212 max_uid
= init_label_info (f
) + 1;
214 /* Leave some extra room for labels and duplicate exit test insns
216 max_jump_chain
= max_uid
* 14 / 10;
217 jump_chain
= (rtx
*) xcalloc (max_jump_chain
, sizeof (rtx
));
219 mark_all_labels (f
, cross_jump
);
221 /* Keep track of labels used from static data; we don't track them
222 closely enough to delete them here, so make sure their reference
223 count doesn't drop to zero. */
225 for (insn
= forced_labels
; insn
; insn
= XEXP (insn
, 1))
226 if (GET_CODE (XEXP (insn
, 0)) == CODE_LABEL
)
227 LABEL_NUSES (XEXP (insn
, 0))++;
229 /* Keep track of labels used for marking handlers for exception
230 regions; they cannot usually be deleted. */
232 for (insn
= exception_handler_labels
; insn
; insn
= XEXP (insn
, 1))
233 if (GET_CODE (XEXP (insn
, 0)) == CODE_LABEL
)
234 LABEL_NUSES (XEXP (insn
, 0))++;
236 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
237 notes and recompute LABEL_NUSES. */
238 if (mark_labels_only
)
241 delete_barrier_successors (f
);
243 last_insn
= delete_unreferenced_labels (f
);
246 delete_noop_moves (f
);
248 /* If we haven't yet gotten to reload and we have just run regscan,
249 delete any insn that sets a register that isn't used elsewhere.
250 This helps some of the optimizations below by having less insns
251 being jumped around. */
253 if (optimize
&& ! reload_completed
&& after_regscan
)
254 for (insn
= f
; insn
; insn
= next
)
256 rtx set
= single_set (insn
);
258 next
= NEXT_INSN (insn
);
260 if (set
&& GET_CODE (SET_DEST (set
)) == REG
261 && REGNO (SET_DEST (set
)) >= FIRST_PSEUDO_REGISTER
262 && REGNO_FIRST_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
263 /* We use regno_last_note_uid so as not to delete the setting
264 of a reg that's used in notes. A subsequent optimization
265 might arrange to use that reg for real. */
266 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
267 && ! side_effects_p (SET_SRC (set
))
268 && ! find_reg_note (insn
, REG_RETVAL
, 0)
269 /* An ADDRESSOF expression can turn into a use of the internal arg
270 pointer, so do not delete the initialization of the internal
271 arg pointer yet. If it is truly dead, flow will delete the
272 initializing insn. */
273 && SET_DEST (set
) != current_function_internal_arg_pointer
)
277 /* Now iterate optimizing jumps until nothing changes over one pass. */
279 old_max_reg
= max_reg_num ();
284 for (insn
= f
; insn
; insn
= next
)
287 rtx temp
, temp1
, temp2
= NULL_RTX
;
288 rtx temp4 ATTRIBUTE_UNUSED
;
290 int this_is_any_uncondjump
;
291 int this_is_any_condjump
;
292 int this_is_onlyjump
;
294 next
= NEXT_INSN (insn
);
296 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
297 jump. Try to optimize by duplicating the loop exit test if so.
298 This is only safe immediately after regscan, because it uses
299 the values of regno_first_uid and regno_last_uid. */
300 if (after_regscan
&& GET_CODE (insn
) == NOTE
301 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
302 && (temp1
= next_nonnote_insn (insn
)) != 0
303 && any_uncondjump_p (temp1
)
304 && onlyjump_p (temp1
))
306 temp
= PREV_INSN (insn
);
307 if (duplicate_loop_exit_test (insn
))
310 next
= NEXT_INSN (temp
);
315 if (GET_CODE (insn
) != JUMP_INSN
)
318 this_is_any_condjump
= any_condjump_p (insn
);
319 this_is_any_uncondjump
= any_uncondjump_p (insn
);
320 this_is_onlyjump
= onlyjump_p (insn
);
322 /* Tension the labels in dispatch tables. */
324 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
)
325 changed
|= tension_vector_labels (PATTERN (insn
), 0);
326 if (GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
327 changed
|= tension_vector_labels (PATTERN (insn
), 1);
329 /* See if this jump goes to another jump and redirect if so. */
330 nlabel
= follow_jumps (JUMP_LABEL (insn
));
331 if (nlabel
!= JUMP_LABEL (insn
))
332 changed
|= redirect_jump (insn
, nlabel
, 1);
334 if (! optimize
|| minimal
)
337 /* If a dispatch table always goes to the same place,
338 get rid of it and replace the insn that uses it. */
340 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
341 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
344 rtx pat
= PATTERN (insn
);
345 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
346 int len
= XVECLEN (pat
, diff_vec_p
);
347 rtx dispatch
= prev_real_insn (insn
);
350 for (i
= 0; i
< len
; i
++)
351 if (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)
352 != XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0))
357 && GET_CODE (dispatch
) == JUMP_INSN
358 && JUMP_LABEL (dispatch
) != 0
359 /* Don't mess with a casesi insn.
360 XXX according to the comment before computed_jump_p(),
361 all casesi insns should be a parallel of the jump
362 and a USE of a LABEL_REF. */
363 && ! ((set
= single_set (dispatch
)) != NULL
364 && (GET_CODE (SET_SRC (set
)) == IF_THEN_ELSE
))
365 && next_real_insn (JUMP_LABEL (dispatch
)) == insn
)
367 redirect_tablejump (dispatch
,
368 XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0));
373 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
375 /* Detect jump to following insn. */
376 if (reallabelprev
== insn
377 && (this_is_any_condjump
|| this_is_any_uncondjump
)
380 next
= next_real_insn (JUMP_LABEL (insn
));
383 /* Remove the "inactive" but "real" insns (i.e. uses and
384 clobbers) in between here and there. */
386 while ((temp
= next_real_insn (temp
)) != next
)
393 /* Detect a conditional jump going to the same place
394 as an immediately following unconditional jump. */
395 else if (this_is_any_condjump
&& this_is_onlyjump
396 && (temp
= next_active_insn (insn
)) != 0
397 && simplejump_p (temp
)
398 && (next_active_insn (JUMP_LABEL (insn
))
399 == next_active_insn (JUMP_LABEL (temp
))))
401 /* Don't mess up test coverage analysis. */
403 if (flag_test_coverage
&& !reload_completed
)
404 for (temp2
= insn
; temp2
!= temp
; temp2
= NEXT_INSN (temp2
))
405 if (GET_CODE (temp2
) == NOTE
&& NOTE_LINE_NUMBER (temp2
) > 0)
410 /* Ensure that we jump to the later of the two labels.
421 If we leave the goto L1, we'll incorrectly leave
422 return-reg dead for TEST true. */
424 temp2
= next_active_insn (JUMP_LABEL (insn
));
426 temp2
= get_last_insn ();
427 if (GET_CODE (temp2
) != CODE_LABEL
)
428 temp2
= prev_label (temp2
);
429 if (temp2
!= JUMP_LABEL (temp
))
430 redirect_jump (temp
, temp2
, 1);
438 /* Detect a conditional jump jumping over an unconditional jump. */
440 else if (this_is_any_condjump
441 && reallabelprev
!= 0
442 && GET_CODE (reallabelprev
) == JUMP_INSN
443 && prev_active_insn (reallabelprev
) == insn
444 && no_labels_between_p (insn
, reallabelprev
)
445 && any_uncondjump_p (reallabelprev
)
446 && onlyjump_p (reallabelprev
))
448 /* When we invert the unconditional jump, we will be
449 decrementing the usage count of its old label.
450 Make sure that we don't delete it now because that
451 might cause the following code to be deleted. */
452 rtx prev_uses
= prev_nonnote_insn (reallabelprev
);
453 rtx prev_label
= JUMP_LABEL (insn
);
456 ++LABEL_NUSES (prev_label
);
458 if (invert_jump (insn
, JUMP_LABEL (reallabelprev
), 1))
460 /* It is very likely that if there are USE insns before
461 this jump, they hold REG_DEAD notes. These REG_DEAD
462 notes are no longer valid due to this optimization,
463 and will cause the life-analysis that following passes
464 (notably delayed-branch scheduling) to think that
465 these registers are dead when they are not.
467 To prevent this trouble, we just remove the USE insns
468 from the insn chain. */
470 while (prev_uses
&& GET_CODE (prev_uses
) == INSN
471 && GET_CODE (PATTERN (prev_uses
)) == USE
)
473 rtx useless
= prev_uses
;
474 prev_uses
= prev_nonnote_insn (prev_uses
);
475 delete_insn (useless
);
478 delete_insn (reallabelprev
);
482 /* We can now safely delete the label if it is unreferenced
483 since the delete_insn above has deleted the BARRIER. */
484 if (prev_label
&& --LABEL_NUSES (prev_label
) == 0)
485 delete_insn (prev_label
);
487 next
= NEXT_INSN (insn
);
490 /* If we have an unconditional jump preceded by a USE, try to put
491 the USE before the target and jump there. This simplifies many
492 of the optimizations below since we don't have to worry about
493 dealing with these USE insns. We only do this if the label
494 being branch to already has the identical USE or if code
495 never falls through to that label. */
497 else if (this_is_any_uncondjump
498 && (temp
= prev_nonnote_insn (insn
)) != 0
499 && GET_CODE (temp
) == INSN
500 && GET_CODE (PATTERN (temp
)) == USE
501 && (temp1
= prev_nonnote_insn (JUMP_LABEL (insn
))) != 0
502 && (GET_CODE (temp1
) == BARRIER
503 || (GET_CODE (temp1
) == INSN
504 && rtx_equal_p (PATTERN (temp
), PATTERN (temp1
))))
505 /* Don't do this optimization if we have a loop containing
506 only the USE instruction, and the loop start label has
507 a usage count of 1. This is because we will redo this
508 optimization everytime through the outer loop, and jump
509 opt will never exit. */
510 && ! ((temp2
= prev_nonnote_insn (temp
)) != 0
511 && temp2
== JUMP_LABEL (insn
)
512 && LABEL_NUSES (temp2
) == 1))
514 if (GET_CODE (temp1
) == BARRIER
)
516 emit_insn_after (PATTERN (temp
), temp1
);
517 temp1
= NEXT_INSN (temp1
);
521 redirect_jump (insn
, get_label_before (temp1
), 1);
522 reallabelprev
= prev_real_insn (temp1
);
524 next
= NEXT_INSN (insn
);
528 /* Detect a conditional jump jumping over an unconditional trap. */
530 && this_is_any_condjump
&& this_is_onlyjump
531 && reallabelprev
!= 0
532 && GET_CODE (reallabelprev
) == INSN
533 && GET_CODE (PATTERN (reallabelprev
)) == TRAP_IF
534 && TRAP_CONDITION (PATTERN (reallabelprev
)) == const_true_rtx
535 && prev_active_insn (reallabelprev
) == insn
536 && no_labels_between_p (insn
, reallabelprev
)
537 && (temp2
= get_condition (insn
, &temp4
))
538 && ((reversed_code
= reversed_comparison_code (temp2
, insn
))
541 rtx
new = gen_cond_trap (reversed_code
,
542 XEXP (temp2
, 0), XEXP (temp2
, 1),
543 TRAP_CODE (PATTERN (reallabelprev
)));
547 emit_insn_before (new, temp4
);
548 delete_insn (reallabelprev
);
554 /* Detect a jump jumping to an unconditional trap. */
555 else if (HAVE_trap
&& this_is_onlyjump
556 && (temp
= next_active_insn (JUMP_LABEL (insn
)))
557 && GET_CODE (temp
) == INSN
558 && GET_CODE (PATTERN (temp
)) == TRAP_IF
559 && (this_is_any_uncondjump
560 || (this_is_any_condjump
561 && (temp2
= get_condition (insn
, &temp4
)))))
563 rtx tc
= TRAP_CONDITION (PATTERN (temp
));
565 if (tc
== const_true_rtx
566 || (! this_is_any_uncondjump
&& rtx_equal_p (temp2
, tc
)))
569 /* Replace an unconditional jump to a trap with a trap. */
570 if (this_is_any_uncondjump
)
572 emit_barrier_after (emit_insn_before (gen_trap (), insn
));
577 new = gen_cond_trap (GET_CODE (temp2
), XEXP (temp2
, 0),
579 TRAP_CODE (PATTERN (temp
)));
582 emit_insn_before (new, temp4
);
588 /* If the trap condition and jump condition are mutually
589 exclusive, redirect the jump to the following insn. */
590 else if (GET_RTX_CLASS (GET_CODE (tc
)) == '<'
591 && this_is_any_condjump
592 && swap_condition (GET_CODE (temp2
)) == GET_CODE (tc
)
593 && rtx_equal_p (XEXP (tc
, 0), XEXP (temp2
, 0))
594 && rtx_equal_p (XEXP (tc
, 1), XEXP (temp2
, 1))
595 && redirect_jump (insn
, get_label_after (temp
), 1))
604 /* Now that the jump has been tensioned,
605 try cross jumping: check for identical code
606 before the jump and before its target label. */
608 /* First, cross jumping of conditional jumps: */
610 if (cross_jump
&& condjump_p (insn
))
612 rtx newjpos
, newlpos
;
613 rtx x
= prev_real_insn (JUMP_LABEL (insn
));
615 /* A conditional jump may be crossjumped
616 only if the place it jumps to follows
617 an opposing jump that comes back here. */
619 if (x
!= 0 && ! jump_back_p (x
, insn
))
620 /* We have no opposing jump;
621 cannot cross jump this insn. */
625 /* TARGET is nonzero if it is ok to cross jump
626 to code before TARGET. If so, see if matches. */
628 find_cross_jump (insn
, x
, 2,
633 do_cross_jump (insn
, newjpos
, newlpos
);
634 /* Make the old conditional jump
635 into an unconditional one. */
636 SET_SRC (PATTERN (insn
))
637 = gen_rtx_LABEL_REF (VOIDmode
, JUMP_LABEL (insn
));
638 INSN_CODE (insn
) = -1;
639 emit_barrier_after (insn
);
640 /* Add to jump_chain unless this is a new label
641 whose UID is too large. */
642 if (INSN_UID (JUMP_LABEL (insn
)) < max_jump_chain
)
644 jump_chain
[INSN_UID (insn
)]
645 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
646 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
653 /* Cross jumping of unconditional jumps:
654 a few differences. */
656 if (cross_jump
&& simplejump_p (insn
))
658 rtx newjpos
, newlpos
;
663 /* TARGET is nonzero if it is ok to cross jump
664 to code before TARGET. If so, see if matches. */
665 find_cross_jump (insn
, JUMP_LABEL (insn
), 1,
668 /* If cannot cross jump to code before the label,
669 see if we can cross jump to another jump to
671 /* Try each other jump to this label. */
672 if (INSN_UID (JUMP_LABEL (insn
)) < max_uid
)
673 for (target
= jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
674 target
!= 0 && newjpos
== 0;
675 target
= jump_chain
[INSN_UID (target
)])
677 && JUMP_LABEL (target
) == JUMP_LABEL (insn
)
678 /* Ignore TARGET if it's deleted. */
679 && ! INSN_DELETED_P (target
))
680 find_cross_jump (insn
, target
, 2,
685 do_cross_jump (insn
, newjpos
, newlpos
);
691 /* This code was dead in the previous jump.c! */
692 if (cross_jump
&& GET_CODE (PATTERN (insn
)) == RETURN
)
694 /* Return insns all "jump to the same place"
695 so we can cross-jump between any two of them. */
697 rtx newjpos
, newlpos
, target
;
701 /* If cannot cross jump to code before the label,
702 see if we can cross jump to another jump to
704 /* Try each other jump to this label. */
705 for (target
= jump_chain
[0];
706 target
!= 0 && newjpos
== 0;
707 target
= jump_chain
[INSN_UID (target
)])
709 && ! INSN_DELETED_P (target
)
710 && GET_CODE (PATTERN (target
)) == RETURN
)
711 find_cross_jump (insn
, target
, 2,
716 do_cross_jump (insn
, newjpos
, newlpos
);
727 /* Delete extraneous line number notes.
728 Note that two consecutive notes for different lines are not really
729 extraneous. There should be some indication where that line belonged,
730 even if it became empty. */
735 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
736 if (GET_CODE (insn
) == NOTE
)
738 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_FUNCTION_BEG
)
739 /* Any previous line note was for the prologue; gdb wants a new
740 note after the prologue even if it is for the same line. */
741 last_note
= NULL_RTX
;
742 else if (NOTE_LINE_NUMBER (insn
) >= 0)
744 /* Delete this note if it is identical to previous note. */
746 && NOTE_SOURCE_FILE (insn
) == NOTE_SOURCE_FILE (last_note
)
747 && NOTE_LINE_NUMBER (insn
) == NOTE_LINE_NUMBER (last_note
))
764 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
765 notes whose labels don't occur in the insn any more. Returns the
766 largest INSN_UID found. */
774 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
776 if (GET_CODE (insn
) == CODE_LABEL
)
777 LABEL_NUSES (insn
) = (LABEL_PRESERVE_P (insn
) != 0);
778 else if (GET_CODE (insn
) == JUMP_INSN
)
779 JUMP_LABEL (insn
) = 0;
780 else if (GET_CODE (insn
) == INSN
|| GET_CODE (insn
) == CALL_INSN
)
784 for (note
= REG_NOTES (insn
); note
; note
= next
)
786 next
= XEXP (note
, 1);
787 if (REG_NOTE_KIND (note
) == REG_LABEL
788 && ! reg_mentioned_p (XEXP (note
, 0), PATTERN (insn
)))
789 remove_note (insn
, note
);
792 if (INSN_UID (insn
) > largest_uid
)
793 largest_uid
= INSN_UID (insn
);
799 /* Delete insns following barriers, up to next label.
801 Also delete no-op jumps created by gcse. */
804 delete_barrier_successors (f
)
810 for (insn
= f
; insn
;)
812 if (GET_CODE (insn
) == BARRIER
)
814 insn
= NEXT_INSN (insn
);
816 never_reached_warning (insn
);
818 while (insn
!= 0 && GET_CODE (insn
) != CODE_LABEL
)
820 if (GET_CODE (insn
) == JUMP_INSN
)
822 /* Detect when we're deleting a tablejump; get rid of
823 the jump table as well. */
824 rtx next1
= next_nonnote_insn (insn
);
825 rtx next2
= next1
? next_nonnote_insn (next1
) : 0;
826 if (next2
&& GET_CODE (next1
) == CODE_LABEL
827 && GET_CODE (next2
) == JUMP_INSN
828 && (GET_CODE (PATTERN (next2
)) == ADDR_VEC
829 || GET_CODE (PATTERN (next2
)) == ADDR_DIFF_VEC
))
835 insn
= delete_insn (insn
);
837 else if (GET_CODE (insn
) == NOTE
838 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)
839 insn
= NEXT_INSN (insn
);
841 insn
= delete_insn (insn
);
843 /* INSN is now the code_label. */
846 /* Also remove (set (pc) (pc)) insns which can be created by
847 gcse. We eliminate such insns now to avoid having them
848 cause problems later. */
849 else if (GET_CODE (insn
) == JUMP_INSN
850 && (set
= pc_set (insn
)) != NULL
851 && SET_SRC (set
) == pc_rtx
852 && SET_DEST (set
) == pc_rtx
853 && onlyjump_p (insn
))
854 insn
= delete_insn (insn
);
857 insn
= NEXT_INSN (insn
);
861 /* Mark the label each jump jumps to.
862 Combine consecutive labels, and count uses of labels.
864 For each label, make a chain (using `jump_chain')
865 of all the *unconditional* jumps that jump to it;
866 also make a chain of all returns.
868 CROSS_JUMP indicates whether we are doing cross jumping
869 and if we are whether we will be paying attention to
870 death notes or not. */
873 mark_all_labels (f
, cross_jump
)
879 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
882 if (GET_CODE (insn
) == CALL_INSN
883 && GET_CODE (PATTERN (insn
)) == CALL_PLACEHOLDER
)
885 mark_all_labels (XEXP (PATTERN (insn
), 0), cross_jump
);
886 mark_all_labels (XEXP (PATTERN (insn
), 1), cross_jump
);
887 mark_all_labels (XEXP (PATTERN (insn
), 2), cross_jump
);
889 /* Canonicalize the tail recursion label attached to the
890 CALL_PLACEHOLDER insn. */
891 if (XEXP (PATTERN (insn
), 3))
893 rtx label_ref
= gen_rtx_LABEL_REF (VOIDmode
,
894 XEXP (PATTERN (insn
), 3));
895 mark_jump_label (label_ref
, insn
, cross_jump
, 0);
896 XEXP (PATTERN (insn
), 3) = XEXP (label_ref
, 0);
902 mark_jump_label (PATTERN (insn
), insn
, cross_jump
, 0);
903 if (! INSN_DELETED_P (insn
) && GET_CODE (insn
) == JUMP_INSN
)
905 /* When we know the LABEL_REF contained in a REG used in
906 an indirect jump, we'll have a REG_LABEL note so that
907 flow can tell where it's going. */
908 if (JUMP_LABEL (insn
) == 0)
910 rtx label_note
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
913 /* But a LABEL_REF around the REG_LABEL note, so
914 that we can canonicalize it. */
915 rtx label_ref
= gen_rtx_LABEL_REF (VOIDmode
,
916 XEXP (label_note
, 0));
918 mark_jump_label (label_ref
, insn
, cross_jump
, 0);
919 XEXP (label_note
, 0) = XEXP (label_ref
, 0);
920 JUMP_LABEL (insn
) = XEXP (label_note
, 0);
923 if (JUMP_LABEL (insn
) != 0 && simplejump_p (insn
))
925 jump_chain
[INSN_UID (insn
)]
926 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
927 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
929 if (GET_CODE (PATTERN (insn
)) == RETURN
)
931 jump_chain
[INSN_UID (insn
)] = jump_chain
[0];
932 jump_chain
[0] = insn
;
938 /* Delete all labels already not referenced.
939 Also find and return the last insn. */
942 delete_unreferenced_labels (f
)
945 rtx final
= NULL_RTX
;
948 for (insn
= f
; insn
;)
950 if (GET_CODE (insn
) == CODE_LABEL
951 && LABEL_NUSES (insn
) == 0
952 && LABEL_ALTERNATE_NAME (insn
) == NULL
)
953 insn
= delete_insn (insn
);
957 insn
= NEXT_INSN (insn
);
964 /* Delete various simple forms of moves which have no necessary
968 delete_noop_moves (f
)
973 for (insn
= f
; insn
;)
975 next
= NEXT_INSN (insn
);
977 if (GET_CODE (insn
) == INSN
)
979 register rtx body
= PATTERN (insn
);
981 /* Detect and delete no-op move instructions
982 resulting from not allocating a parameter in a register. */
984 if (GET_CODE (body
) == SET
985 && (SET_DEST (body
) == SET_SRC (body
)
986 || (GET_CODE (SET_DEST (body
)) == MEM
987 && GET_CODE (SET_SRC (body
)) == MEM
988 && rtx_equal_p (SET_SRC (body
), SET_DEST (body
))))
989 && ! (GET_CODE (SET_DEST (body
)) == MEM
990 && MEM_VOLATILE_P (SET_DEST (body
)))
991 && ! (GET_CODE (SET_SRC (body
)) == MEM
992 && MEM_VOLATILE_P (SET_SRC (body
))))
993 delete_computation (insn
);
995 /* Detect and ignore no-op move instructions
996 resulting from smart or fortuitous register allocation. */
998 else if (GET_CODE (body
) == SET
)
1000 int sreg
= true_regnum (SET_SRC (body
));
1001 int dreg
= true_regnum (SET_DEST (body
));
1003 if (sreg
== dreg
&& sreg
>= 0)
1005 else if (sreg
>= 0 && dreg
>= 0)
1008 rtx tem
= find_equiv_reg (NULL_RTX
, insn
, 0,
1009 sreg
, NULL_PTR
, dreg
,
1010 GET_MODE (SET_SRC (body
)));
1013 && GET_MODE (tem
) == GET_MODE (SET_DEST (body
)))
1015 /* DREG may have been the target of a REG_DEAD note in
1016 the insn which makes INSN redundant. If so, reorg
1017 would still think it is dead. So search for such a
1018 note and delete it if we find it. */
1019 if (! find_regno_note (insn
, REG_UNUSED
, dreg
))
1020 for (trial
= prev_nonnote_insn (insn
);
1021 trial
&& GET_CODE (trial
) != CODE_LABEL
;
1022 trial
= prev_nonnote_insn (trial
))
1023 if (find_regno_note (trial
, REG_DEAD
, dreg
))
1025 remove_death (dreg
, trial
);
1029 /* Deleting insn could lose a death-note for SREG. */
1030 if ((trial
= find_regno_note (insn
, REG_DEAD
, sreg
)))
1032 /* Change this into a USE so that we won't emit
1033 code for it, but still can keep the note. */
1035 = gen_rtx_USE (VOIDmode
, XEXP (trial
, 0));
1036 INSN_CODE (insn
) = -1;
1037 /* Remove all reg notes but the REG_DEAD one. */
1038 REG_NOTES (insn
) = trial
;
1039 XEXP (trial
, 1) = NULL_RTX
;
1045 else if (dreg
>= 0 && CONSTANT_P (SET_SRC (body
))
1046 && find_equiv_reg (SET_SRC (body
), insn
, 0, dreg
,
1048 GET_MODE (SET_DEST (body
))))
1050 /* This handles the case where we have two consecutive
1051 assignments of the same constant to pseudos that didn't
1052 get a hard reg. Each SET from the constant will be
1053 converted into a SET of the spill register and an
1054 output reload will be made following it. This produces
1055 two loads of the same constant into the same spill
1060 /* Look back for a death note for the first reg.
1061 If there is one, it is no longer accurate. */
1062 while (in_insn
&& GET_CODE (in_insn
) != CODE_LABEL
)
1064 if ((GET_CODE (in_insn
) == INSN
1065 || GET_CODE (in_insn
) == JUMP_INSN
)
1066 && find_regno_note (in_insn
, REG_DEAD
, dreg
))
1068 remove_death (dreg
, in_insn
);
1071 in_insn
= PREV_INSN (in_insn
);
1074 /* Delete the second load of the value. */
1078 else if (GET_CODE (body
) == PARALLEL
)
1080 /* If each part is a set between two identical registers or
1081 a USE or CLOBBER, delete the insn. */
1085 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; i
--)
1087 tem
= XVECEXP (body
, 0, i
);
1088 if (GET_CODE (tem
) == USE
|| GET_CODE (tem
) == CLOBBER
)
1091 if (GET_CODE (tem
) != SET
1092 || (sreg
= true_regnum (SET_SRC (tem
))) < 0
1093 || (dreg
= true_regnum (SET_DEST (tem
))) < 0
1101 /* Also delete insns to store bit fields if they are no-ops. */
1102 /* Not worth the hair to detect this in the big-endian case. */
1103 else if (! BYTES_BIG_ENDIAN
1104 && GET_CODE (body
) == SET
1105 && GET_CODE (SET_DEST (body
)) == ZERO_EXTRACT
1106 && XEXP (SET_DEST (body
), 2) == const0_rtx
1107 && XEXP (SET_DEST (body
), 0) == SET_SRC (body
)
1108 && ! (GET_CODE (SET_SRC (body
)) == MEM
1109 && MEM_VOLATILE_P (SET_SRC (body
))))
1116 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
1117 jump. Assume that this unconditional jump is to the exit test code. If
1118 the code is sufficiently simple, make a copy of it before INSN,
1119 followed by a jump to the exit of the loop. Then delete the unconditional
1122 Return 1 if we made the change, else 0.
1124 This is only safe immediately after a regscan pass because it uses the
1125 values of regno_first_uid and regno_last_uid. */
1128 duplicate_loop_exit_test (loop_start
)
1131 rtx insn
, set
, reg
, p
, link
;
1132 rtx copy
= 0, first_copy
= 0;
1134 rtx exitcode
= NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start
)));
1136 int max_reg
= max_reg_num ();
1139 /* Scan the exit code. We do not perform this optimization if any insn:
1143 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
1144 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
1145 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
1148 We also do not do this if we find an insn with ASM_OPERANDS. While
1149 this restriction should not be necessary, copying an insn with
1150 ASM_OPERANDS can confuse asm_noperands in some cases.
1152 Also, don't do this if the exit code is more than 20 insns. */
1154 for (insn
= exitcode
;
1156 && ! (GET_CODE (insn
) == NOTE
1157 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
);
1158 insn
= NEXT_INSN (insn
))
1160 switch (GET_CODE (insn
))
1166 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
1167 a jump immediately after the loop start that branches outside
1168 the loop but within an outer loop, near the exit test.
1169 If we copied this exit test and created a phony
1170 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
1171 before the exit test look like these could be safely moved
1172 out of the loop even if they actually may be never executed.
1173 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
1175 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
1176 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
)
1180 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
1181 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
))
1182 /* If we were to duplicate this code, we would not move
1183 the BLOCK notes, and so debugging the moved code would
1184 be difficult. Thus, we only move the code with -O2 or
1191 /* The code below would grossly mishandle REG_WAS_0 notes,
1192 so get rid of them here. */
1193 while ((p
= find_reg_note (insn
, REG_WAS_0
, NULL_RTX
)) != 0)
1194 remove_note (insn
, p
);
1195 if (++num_insns
> 20
1196 || find_reg_note (insn
, REG_RETVAL
, NULL_RTX
)
1197 || find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
1205 /* Unless INSN is zero, we can do the optimization. */
1211 /* See if any insn sets a register only used in the loop exit code and
1212 not a user variable. If so, replace it with a new register. */
1213 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
1214 if (GET_CODE (insn
) == INSN
1215 && (set
= single_set (insn
)) != 0
1216 && ((reg
= SET_DEST (set
), GET_CODE (reg
) == REG
)
1217 || (GET_CODE (reg
) == SUBREG
1218 && (reg
= SUBREG_REG (reg
), GET_CODE (reg
) == REG
)))
1219 && REGNO (reg
) >= FIRST_PSEUDO_REGISTER
1220 && REGNO_FIRST_UID (REGNO (reg
)) == INSN_UID (insn
))
1222 for (p
= NEXT_INSN (insn
); p
!= lastexit
; p
= NEXT_INSN (p
))
1223 if (REGNO_LAST_UID (REGNO (reg
)) == INSN_UID (p
))
1228 /* We can do the replacement. Allocate reg_map if this is the
1229 first replacement we found. */
1231 reg_map
= (rtx
*) xcalloc (max_reg
, sizeof (rtx
));
1233 REG_LOOP_TEST_P (reg
) = 1;
1235 reg_map
[REGNO (reg
)] = gen_reg_rtx (GET_MODE (reg
));
1239 /* Now copy each insn. */
1240 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
1242 switch (GET_CODE (insn
))
1245 copy
= emit_barrier_before (loop_start
);
1248 /* Only copy line-number notes. */
1249 if (NOTE_LINE_NUMBER (insn
) >= 0)
1251 copy
= emit_note_before (NOTE_LINE_NUMBER (insn
), loop_start
);
1252 NOTE_SOURCE_FILE (copy
) = NOTE_SOURCE_FILE (insn
);
1257 copy
= emit_insn_before (copy_insn (PATTERN (insn
)), loop_start
);
1259 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
1261 mark_jump_label (PATTERN (copy
), copy
, 0, 0);
1263 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
1265 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
1266 if (REG_NOTE_KIND (link
) != REG_LABEL
)
1268 if (GET_CODE (link
) == EXPR_LIST
)
1270 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link
),
1275 = copy_insn_1 (gen_rtx_INSN_LIST (REG_NOTE_KIND (link
),
1280 if (reg_map
&& REG_NOTES (copy
))
1281 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
1285 copy
= emit_jump_insn_before (copy_insn (PATTERN (insn
)),
1288 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
1289 mark_jump_label (PATTERN (copy
), copy
, 0, 0);
1290 if (REG_NOTES (insn
))
1292 REG_NOTES (copy
) = copy_insn_1 (REG_NOTES (insn
));
1294 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
1297 /* If this is a simple jump, add it to the jump chain. */
1299 if (INSN_UID (copy
) < max_jump_chain
&& JUMP_LABEL (copy
)
1300 && simplejump_p (copy
))
1302 jump_chain
[INSN_UID (copy
)]
1303 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
1304 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
1312 /* Record the first insn we copied. We need it so that we can
1313 scan the copied insns for new pseudo registers. */
1318 /* Now clean up by emitting a jump to the end label and deleting the jump
1319 at the start of the loop. */
1320 if (! copy
|| GET_CODE (copy
) != BARRIER
)
1322 copy
= emit_jump_insn_before (gen_jump (get_label_after (insn
)),
1325 /* Record the first insn we copied. We need it so that we can
1326 scan the copied insns for new pseudo registers. This may not
1327 be strictly necessary since we should have copied at least one
1328 insn above. But I am going to be safe. */
1332 mark_jump_label (PATTERN (copy
), copy
, 0, 0);
1333 if (INSN_UID (copy
) < max_jump_chain
1334 && INSN_UID (JUMP_LABEL (copy
)) < max_jump_chain
)
1336 jump_chain
[INSN_UID (copy
)]
1337 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
1338 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
1340 emit_barrier_before (loop_start
);
1343 /* Now scan from the first insn we copied to the last insn we copied
1344 (copy) for new pseudo registers. Do this after the code to jump to
1345 the end label since that might create a new pseudo too. */
1346 reg_scan_update (first_copy
, copy
, max_reg
);
1348 /* Mark the exit code as the virtual top of the converted loop. */
1349 emit_note_before (NOTE_INSN_LOOP_VTOP
, exitcode
);
1351 delete_insn (next_nonnote_insn (loop_start
));
1360 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
1361 notes between START and END out before START. Assume that END is not
1362 such a note. START may be such a note. Returns the value of the new
1363 starting insn, which may be different if the original start was such a
1367 squeeze_notes (start
, end
)
1373 for (insn
= start
; insn
!= end
; insn
= next
)
1375 next
= NEXT_INSN (insn
);
1376 if (GET_CODE (insn
) == NOTE
1377 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
1378 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
1379 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
1380 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
1381 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
1382 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_VTOP
))
1388 rtx prev
= PREV_INSN (insn
);
1389 PREV_INSN (insn
) = PREV_INSN (start
);
1390 NEXT_INSN (insn
) = start
;
1391 NEXT_INSN (PREV_INSN (insn
)) = insn
;
1392 PREV_INSN (NEXT_INSN (insn
)) = insn
;
1393 NEXT_INSN (prev
) = next
;
1394 PREV_INSN (next
) = prev
;
1402 /* Compare the instructions before insn E1 with those before E2
1403 to find an opportunity for cross jumping.
1404 (This means detecting identical sequences of insns followed by
1405 jumps to the same place, or followed by a label and a jump
1406 to that label, and replacing one with a jump to the other.)
1408 Assume E1 is a jump that jumps to label E2
1409 (that is not always true but it might as well be).
1410 Find the longest possible equivalent sequences
1411 and store the first insns of those sequences into *F1 and *F2.
1412 Store zero there if no equivalent preceding instructions are found.
1414 We give up if we find a label in stream 1.
1415 Actually we could transfer that label into stream 2. */
1418 find_cross_jump (e1
, e2
, minimum
, f1
, f2
)
1423 register rtx i1
= e1
, i2
= e2
;
1424 register rtx p1
, p2
;
1427 rtx last1
= 0, last2
= 0;
1428 rtx afterlast1
= 0, afterlast2
= 0;
1435 i1
= prev_nonnote_insn (i1
);
1437 i2
= PREV_INSN (i2
);
1438 while (i2
&& (GET_CODE (i2
) == NOTE
|| GET_CODE (i2
) == CODE_LABEL
))
1439 i2
= PREV_INSN (i2
);
1444 /* Don't allow the range of insns preceding E1 or E2
1445 to include the other (E2 or E1). */
1446 if (i2
== e1
|| i1
== e2
)
1449 /* If we will get to this code by jumping, those jumps will be
1450 tensioned to go directly to the new label (before I2),
1451 so this cross-jumping won't cost extra. So reduce the minimum. */
1452 if (GET_CODE (i1
) == CODE_LABEL
)
1458 if (i2
== 0 || GET_CODE (i1
) != GET_CODE (i2
))
1464 /* If this is a CALL_INSN, compare register usage information.
1465 If we don't check this on stack register machines, the two
1466 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1467 numbers of stack registers in the same basic block.
1468 If we don't check this on machines with delay slots, a delay slot may
1469 be filled that clobbers a parameter expected by the subroutine.
1471 ??? We take the simple route for now and assume that if they're
1472 equal, they were constructed identically. */
1474 if (GET_CODE (i1
) == CALL_INSN
1475 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1
),
1476 CALL_INSN_FUNCTION_USAGE (i2
)))
1480 /* If cross_jump_death_matters is not 0, the insn's mode
1481 indicates whether or not the insn contains any stack-like
1484 if (!lose
&& cross_jump_death_matters
&& stack_regs_mentioned (i1
))
1486 /* If register stack conversion has already been done, then
1487 death notes must also be compared before it is certain that
1488 the two instruction streams match. */
1491 HARD_REG_SET i1_regset
, i2_regset
;
1493 CLEAR_HARD_REG_SET (i1_regset
);
1494 CLEAR_HARD_REG_SET (i2_regset
);
1496 for (note
= REG_NOTES (i1
); note
; note
= XEXP (note
, 1))
1497 if (REG_NOTE_KIND (note
) == REG_DEAD
1498 && STACK_REG_P (XEXP (note
, 0)))
1499 SET_HARD_REG_BIT (i1_regset
, REGNO (XEXP (note
, 0)));
1501 for (note
= REG_NOTES (i2
); note
; note
= XEXP (note
, 1))
1502 if (REG_NOTE_KIND (note
) == REG_DEAD
1503 && STACK_REG_P (XEXP (note
, 0)))
1504 SET_HARD_REG_BIT (i2_regset
, REGNO (XEXP (note
, 0)));
1506 GO_IF_HARD_REG_EQUAL (i1_regset
, i2_regset
, done
);
1515 /* Don't allow old-style asm or volatile extended asms to be accepted
1516 for cross jumping purposes. It is conceptually correct to allow
1517 them, since cross-jumping preserves the dynamic instruction order
1518 even though it is changing the static instruction order. However,
1519 if an asm is being used to emit an assembler pseudo-op, such as
1520 the MIPS `.set reorder' pseudo-op, then the static instruction order
1521 matters and it must be preserved. */
1522 if (GET_CODE (p1
) == ASM_INPUT
|| GET_CODE (p2
) == ASM_INPUT
1523 || (GET_CODE (p1
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p1
))
1524 || (GET_CODE (p2
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p2
)))
1527 if (lose
|| GET_CODE (p1
) != GET_CODE (p2
)
1528 || ! rtx_renumbered_equal_p (p1
, p2
))
1530 /* The following code helps take care of G++ cleanups. */
1534 if (!lose
&& GET_CODE (p1
) == GET_CODE (p2
)
1535 && ((equiv1
= find_reg_note (i1
, REG_EQUAL
, NULL_RTX
)) != 0
1536 || (equiv1
= find_reg_note (i1
, REG_EQUIV
, NULL_RTX
)) != 0)
1537 && ((equiv2
= find_reg_note (i2
, REG_EQUAL
, NULL_RTX
)) != 0
1538 || (equiv2
= find_reg_note (i2
, REG_EQUIV
, NULL_RTX
)) != 0)
1539 /* If the equivalences are not to a constant, they may
1540 reference pseudos that no longer exist, so we can't
1542 && CONSTANT_P (XEXP (equiv1
, 0))
1543 && rtx_equal_p (XEXP (equiv1
, 0), XEXP (equiv2
, 0)))
1545 rtx s1
= single_set (i1
);
1546 rtx s2
= single_set (i2
);
1547 if (s1
!= 0 && s2
!= 0
1548 && rtx_renumbered_equal_p (SET_DEST (s1
), SET_DEST (s2
)))
1550 validate_change (i1
, &SET_SRC (s1
), XEXP (equiv1
, 0), 1);
1551 validate_change (i2
, &SET_SRC (s2
), XEXP (equiv2
, 0), 1);
1552 if (! rtx_renumbered_equal_p (p1
, p2
))
1554 else if (apply_change_group ())
1559 /* Insns fail to match; cross jumping is limited to the following
1563 /* Don't allow the insn after a compare to be shared by
1564 cross-jumping unless the compare is also shared.
1565 Here, if either of these non-matching insns is a compare,
1566 exclude the following insn from possible cross-jumping. */
1567 if (sets_cc0_p (p1
) || sets_cc0_p (p2
))
1568 last1
= afterlast1
, last2
= afterlast2
, ++minimum
;
1571 /* If cross-jumping here will feed a jump-around-jump
1572 optimization, this jump won't cost extra, so reduce
1574 if (GET_CODE (i1
) == JUMP_INSN
1576 && prev_real_insn (JUMP_LABEL (i1
)) == e1
)
1582 if (GET_CODE (p1
) != USE
&& GET_CODE (p1
) != CLOBBER
)
1584 /* Ok, this insn is potentially includable in a cross-jump here. */
1585 afterlast1
= last1
, afterlast2
= last2
;
1586 last1
= i1
, last2
= i2
, --minimum
;
1590 if (minimum
<= 0 && last1
!= 0 && last1
!= e1
)
1591 *f1
= last1
, *f2
= last2
;
1595 do_cross_jump (insn
, newjpos
, newlpos
)
1596 rtx insn
, newjpos
, newlpos
;
1598 /* Find an existing label at this point
1599 or make a new one if there is none. */
1600 register rtx label
= get_label_before (newlpos
);
1602 /* Make the same jump insn jump to the new point. */
1603 if (GET_CODE (PATTERN (insn
)) == RETURN
)
1605 /* Remove from jump chain of returns. */
1606 delete_from_jump_chain (insn
);
1607 /* Change the insn. */
1608 PATTERN (insn
) = gen_jump (label
);
1609 INSN_CODE (insn
) = -1;
1610 JUMP_LABEL (insn
) = label
;
1611 LABEL_NUSES (label
)++;
1612 /* Add to new the jump chain. */
1613 if (INSN_UID (label
) < max_jump_chain
1614 && INSN_UID (insn
) < max_jump_chain
)
1616 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (label
)];
1617 jump_chain
[INSN_UID (label
)] = insn
;
1621 redirect_jump (insn
, label
, 1);
1623 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1624 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1625 the NEWJPOS stream. */
1627 while (newjpos
!= insn
)
1631 for (lnote
= REG_NOTES (newlpos
); lnote
; lnote
= XEXP (lnote
, 1))
1632 if ((REG_NOTE_KIND (lnote
) == REG_EQUAL
1633 || REG_NOTE_KIND (lnote
) == REG_EQUIV
)
1634 && ! find_reg_note (newjpos
, REG_EQUAL
, XEXP (lnote
, 0))
1635 && ! find_reg_note (newjpos
, REG_EQUIV
, XEXP (lnote
, 0)))
1636 remove_note (newlpos
, lnote
);
1638 delete_insn (newjpos
);
1639 newjpos
= next_real_insn (newjpos
);
1640 newlpos
= next_real_insn (newlpos
);
1644 /* Return the label before INSN, or put a new label there. */
1647 get_label_before (insn
)
1652 /* Find an existing label at this point
1653 or make a new one if there is none. */
1654 label
= prev_nonnote_insn (insn
);
1656 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
1658 rtx prev
= PREV_INSN (insn
);
1660 label
= gen_label_rtx ();
1661 emit_label_after (label
, prev
);
1662 LABEL_NUSES (label
) = 0;
1667 /* Return the label after INSN, or put a new label there. */
1670 get_label_after (insn
)
1675 /* Find an existing label at this point
1676 or make a new one if there is none. */
1677 label
= next_nonnote_insn (insn
);
1679 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
1681 label
= gen_label_rtx ();
1682 emit_label_after (label
, insn
);
1683 LABEL_NUSES (label
) = 0;
1688 /* Return 1 if INSN is a jump that jumps to right after TARGET
1689 only on the condition that TARGET itself would drop through.
1690 Assumes that TARGET is a conditional jump. */
1693 jump_back_p (insn
, target
)
1697 enum rtx_code codei
, codet
;
1700 if (! any_condjump_p (insn
)
1701 || any_uncondjump_p (target
)
1702 || target
!= prev_real_insn (JUMP_LABEL (insn
)))
1704 set
= pc_set (insn
);
1705 tset
= pc_set (target
);
1707 cinsn
= XEXP (SET_SRC (set
), 0);
1708 ctarget
= XEXP (SET_SRC (tset
), 0);
1710 codei
= GET_CODE (cinsn
);
1711 codet
= GET_CODE (ctarget
);
1713 if (XEXP (SET_SRC (set
), 1) == pc_rtx
)
1715 codei
= reversed_comparison_code (cinsn
, insn
);
1716 if (codei
== UNKNOWN
)
1720 if (XEXP (SET_SRC (tset
), 2) == pc_rtx
)
1722 codet
= reversed_comparison_code (ctarget
, target
);
1723 if (codei
== UNKNOWN
)
1727 return (codei
== codet
1728 && rtx_renumbered_equal_p (XEXP (cinsn
, 0), XEXP (ctarget
, 0))
1729 && rtx_renumbered_equal_p (XEXP (cinsn
, 1), XEXP (ctarget
, 1)));
1732 /* Given a comparison (CODE ARG0 ARG1), inside a insn, INSN, return an code
1733 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
1734 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
1735 know whether it's source is floating point or integer comparison. Machine
1736 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
1737 to help this function avoid overhead in these cases. */
1739 reversed_comparison_code_parts (code
, arg0
, arg1
, insn
)
1740 rtx insn
, arg0
, arg1
;
1743 enum machine_mode mode
;
1745 /* If this is not actually a comparison, we can't reverse it. */
1746 if (GET_RTX_CLASS (code
) != '<')
1749 mode
= GET_MODE (arg0
);
1750 if (mode
== VOIDmode
)
1751 mode
= GET_MODE (arg1
);
1753 /* First see if machine description supply us way to reverse the comparison.
1754 Give it priority over everything else to allow machine description to do
1756 #ifdef REVERSIBLE_CC_MODE
1757 if (GET_MODE_CLASS (mode
) == MODE_CC
1758 && REVERSIBLE_CC_MODE (mode
))
1760 #ifdef REVERSE_CONDITION
1761 return REVERSE_CONDITION (code
, mode
);
1763 return reverse_condition (code
);
1767 /* Try few special cases based on the comparison code. */
1776 /* It is always safe to reverse EQ and NE, even for the floating
1777 point. Similary the unsigned comparisons are never used for
1778 floating point so we can reverse them in the default way. */
1779 return reverse_condition (code
);
1784 /* In case we already see unordered comparison, we can be sure to
1785 be dealing with floating point so we don't need any more tests. */
1786 return reverse_condition_maybe_unordered (code
);
1791 /* We don't have safe way to reverse these yet. */
1797 /* In case we give up IEEE compatibility, all comparisons are reversible. */
1798 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
1800 return reverse_condition (code
);
1802 if (GET_MODE_CLASS (mode
) == MODE_CC
1809 /* Try to search for the comparison to determine the real mode.
1810 This code is expensive, but with sane machine description it
1811 will be never used, since REVERSIBLE_CC_MODE will return true
1816 for (prev
= prev_nonnote_insn (insn
);
1817 prev
!= 0 && GET_CODE (prev
) != CODE_LABEL
;
1818 prev
= prev_nonnote_insn (prev
))
1820 rtx set
= set_of (arg0
, prev
);
1821 if (set
&& GET_CODE (set
) == SET
1822 && rtx_equal_p (SET_DEST (set
), arg0
))
1824 rtx src
= SET_SRC (set
);
1826 if (GET_CODE (src
) == COMPARE
)
1828 rtx comparison
= src
;
1829 arg0
= XEXP (src
, 0);
1830 mode
= GET_MODE (arg0
);
1831 if (mode
== VOIDmode
)
1832 mode
= GET_MODE (XEXP (comparison
, 1));
1835 /* We can get past reg-reg moves. This may be usefull for model
1836 of i387 comparisons that first move flag registers around. */
1843 /* If register is clobbered in some ununderstandable way,
1850 /* An integer condition. */
1851 if (GET_CODE (arg0
) == CONST_INT
1852 || (GET_MODE (arg0
) != VOIDmode
1853 && GET_MODE_CLASS (mode
) != MODE_CC
1854 && ! FLOAT_MODE_P (mode
)))
1855 return reverse_condition (code
);
1860 /* An wrapper around the previous function to take COMPARISON as rtx
1861 expression. This simplifies many callers. */
1863 reversed_comparison_code (comparison
, insn
)
1864 rtx comparison
, insn
;
1866 if (GET_RTX_CLASS (GET_CODE (comparison
)) != '<')
1868 return reversed_comparison_code_parts (GET_CODE (comparison
),
1869 XEXP (comparison
, 0),
1870 XEXP (comparison
, 1), insn
);
1873 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
1874 return non-zero if it is safe to reverse this comparison. It is if our
1875 floating-point is not IEEE, if this is an NE or EQ comparison, or if
1876 this is known to be an integer comparison.
1878 Use of this function is depreached and you should use
1879 REVERSED_COMPARISON_CODE bits instead.
1883 can_reverse_comparison_p (comparison
, insn
)
1889 /* If this is not actually a comparison, we can't reverse it. */
1890 if (GET_RTX_CLASS (GET_CODE (comparison
)) != '<')
1893 code
= reversed_comparison_code (comparison
, insn
);
1894 if (code
== UNKNOWN
)
1897 /* The code will follow can_reverse_comparison_p with reverse_condition,
1898 so see if it will get proper result. */
1899 return (code
== reverse_condition (GET_CODE (comparison
)));
1902 /* Given an rtx-code for a comparison, return the code for the negated
1903 comparison. If no such code exists, return UNKNOWN.
1905 WATCH OUT! reverse_condition is not safe to use on a jump that might
1906 be acting on the results of an IEEE floating point comparison, because
1907 of the special treatment of non-signaling nans in comparisons.
1908 Use reversed_comparison_code instead. */
1911 reverse_condition (code
)
1954 /* Similar, but we're allowed to generate unordered comparisons, which
1955 makes it safe for IEEE floating-point. Of course, we have to recognize
1956 that the target will support them too... */
1959 reverse_condition_maybe_unordered (code
)
1962 /* Non-IEEE formats don't have unordered conditions. */
1963 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
)
1964 return reverse_condition (code
);
2002 /* Similar, but return the code when two operands of a comparison are swapped.
2003 This IS safe for IEEE floating-point. */
2006 swap_condition (code
)
2049 /* Given a comparison CODE, return the corresponding unsigned comparison.
2050 If CODE is an equality comparison or already an unsigned comparison,
2051 CODE is returned. */
2054 unsigned_condition (code
)
2081 /* Similarly, return the signed version of a comparison. */
2084 signed_condition (code
)
2111 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
2112 truth of CODE1 implies the truth of CODE2. */
2115 comparison_dominates_p (code1
, code2
)
2116 enum rtx_code code1
, code2
;
2118 /* UNKNOWN comparison codes can happen as a result of trying to revert
2120 They can't match anything, so we have to reject them here. */
2121 if (code1
== UNKNOWN
|| code2
== UNKNOWN
)
2130 if (code2
== UNLE
|| code2
== UNGE
)
2135 if (code2
== LE
|| code2
== LEU
|| code2
== GE
|| code2
== GEU
2136 || code2
== ORDERED
)
2141 if (code2
== UNLE
|| code2
== NE
)
2146 if (code2
== LE
|| code2
== NE
|| code2
== ORDERED
|| code2
== LTGT
)
2151 if (code2
== UNGE
|| code2
== NE
)
2156 if (code2
== GE
|| code2
== NE
|| code2
== ORDERED
|| code2
== LTGT
)
2162 if (code2
== ORDERED
)
2167 if (code2
== NE
|| code2
== ORDERED
)
2172 if (code2
== LEU
|| code2
== NE
)
2177 if (code2
== GEU
|| code2
== NE
)
2182 if (code2
== NE
|| code2
== UNEQ
|| code2
== UNLE
|| code2
== UNLT
2183 || code2
== UNGE
|| code2
== UNGT
)
2194 /* Return 1 if INSN is an unconditional jump and nothing else. */
2200 return (GET_CODE (insn
) == JUMP_INSN
2201 && GET_CODE (PATTERN (insn
)) == SET
2202 && GET_CODE (SET_DEST (PATTERN (insn
))) == PC
2203 && GET_CODE (SET_SRC (PATTERN (insn
))) == LABEL_REF
);
2206 /* Return nonzero if INSN is a (possibly) conditional jump
2209 Use this function is deprecated, since we need to support combined
2210 branch and compare insns. Use any_condjump_p instead whenever possible. */
2216 register rtx x
= PATTERN (insn
);
2218 if (GET_CODE (x
) != SET
2219 || GET_CODE (SET_DEST (x
)) != PC
)
2223 if (GET_CODE (x
) == LABEL_REF
)
2226 return (GET_CODE (x
) == IF_THEN_ELSE
2227 && ((GET_CODE (XEXP (x
, 2)) == PC
2228 && (GET_CODE (XEXP (x
, 1)) == LABEL_REF
2229 || GET_CODE (XEXP (x
, 1)) == RETURN
))
2230 || (GET_CODE (XEXP (x
, 1)) == PC
2231 && (GET_CODE (XEXP (x
, 2)) == LABEL_REF
2232 || GET_CODE (XEXP (x
, 2)) == RETURN
))));
2237 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2240 Use this function is deprecated, since we need to support combined
2241 branch and compare insns. Use any_condjump_p instead whenever possible. */
2244 condjump_in_parallel_p (insn
)
2247 register rtx x
= PATTERN (insn
);
2249 if (GET_CODE (x
) != PARALLEL
)
2252 x
= XVECEXP (x
, 0, 0);
2254 if (GET_CODE (x
) != SET
)
2256 if (GET_CODE (SET_DEST (x
)) != PC
)
2258 if (GET_CODE (SET_SRC (x
)) == LABEL_REF
)
2260 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
2262 if (XEXP (SET_SRC (x
), 2) == pc_rtx
2263 && (GET_CODE (XEXP (SET_SRC (x
), 1)) == LABEL_REF
2264 || GET_CODE (XEXP (SET_SRC (x
), 1)) == RETURN
))
2266 if (XEXP (SET_SRC (x
), 1) == pc_rtx
2267 && (GET_CODE (XEXP (SET_SRC (x
), 2)) == LABEL_REF
2268 || GET_CODE (XEXP (SET_SRC (x
), 2)) == RETURN
))
2273 /* Return set of PC, otherwise NULL. */
2280 if (GET_CODE (insn
) != JUMP_INSN
)
2282 pat
= PATTERN (insn
);
2284 /* The set is allowed to appear either as the insn pattern or
2285 the first set in a PARALLEL. */
2286 if (GET_CODE (pat
) == PARALLEL
)
2287 pat
= XVECEXP (pat
, 0, 0);
2288 if (GET_CODE (pat
) == SET
&& GET_CODE (SET_DEST (pat
)) == PC
)
2294 /* Return true when insn is an unconditional direct jump,
2295 possibly bundled inside a PARALLEL. */
2298 any_uncondjump_p (insn
)
2301 rtx x
= pc_set (insn
);
2304 if (GET_CODE (SET_SRC (x
)) != LABEL_REF
)
2309 /* Return true when insn is a conditional jump. This function works for
2310 instructions containing PC sets in PARALLELs. The instruction may have
2311 various other effects so before removing the jump you must verify
2314 Note that unlike condjump_p it returns false for unconditional jumps. */
2317 any_condjump_p (insn
)
2320 rtx x
= pc_set (insn
);
2325 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
2328 a
= GET_CODE (XEXP (SET_SRC (x
), 1));
2329 b
= GET_CODE (XEXP (SET_SRC (x
), 2));
2331 return ((b
== PC
&& (a
== LABEL_REF
|| a
== RETURN
))
2332 || (a
== PC
&& (b
== LABEL_REF
|| b
== RETURN
)));
2335 /* Return the label of a conditional jump. */
2338 condjump_label (insn
)
2341 rtx x
= pc_set (insn
);
2346 if (GET_CODE (x
) == LABEL_REF
)
2348 if (GET_CODE (x
) != IF_THEN_ELSE
)
2350 if (XEXP (x
, 2) == pc_rtx
&& GET_CODE (XEXP (x
, 1)) == LABEL_REF
)
2352 if (XEXP (x
, 1) == pc_rtx
&& GET_CODE (XEXP (x
, 2)) == LABEL_REF
)
2357 /* Return true if INSN is a (possibly conditional) return insn. */
2360 returnjump_p_1 (loc
, data
)
2362 void *data ATTRIBUTE_UNUSED
;
2365 return x
&& GET_CODE (x
) == RETURN
;
2372 if (GET_CODE (insn
) != JUMP_INSN
)
2374 return for_each_rtx (&PATTERN (insn
), returnjump_p_1
, NULL
);
2377 /* Return true if INSN is a jump that only transfers control and
2386 if (GET_CODE (insn
) != JUMP_INSN
)
2389 set
= single_set (insn
);
2392 if (GET_CODE (SET_DEST (set
)) != PC
)
2394 if (side_effects_p (SET_SRC (set
)))
2402 /* Return 1 if X is an RTX that does nothing but set the condition codes
2403 and CLOBBER or USE registers.
2404 Return -1 if X does explicitly set the condition codes,
2405 but also does other things. */
2409 rtx x ATTRIBUTE_UNUSED
;
2411 if (GET_CODE (x
) == SET
&& SET_DEST (x
) == cc0_rtx
)
2413 if (GET_CODE (x
) == PARALLEL
)
2417 int other_things
= 0;
2418 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2420 if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
2421 && SET_DEST (XVECEXP (x
, 0, i
)) == cc0_rtx
)
2423 else if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
)
2426 return ! sets_cc0
? 0 : other_things
? -1 : 1;
2432 /* Follow any unconditional jump at LABEL;
2433 return the ultimate label reached by any such chain of jumps.
2434 If LABEL is not followed by a jump, return LABEL.
2435 If the chain loops or we can't find end, return LABEL,
2436 since that tells caller to avoid changing the insn.
2438 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2439 a USE or CLOBBER. */
2442 follow_jumps (label
)
2447 register rtx value
= label
;
2452 && (insn
= next_active_insn (value
)) != 0
2453 && GET_CODE (insn
) == JUMP_INSN
2454 && ((JUMP_LABEL (insn
) != 0 && any_uncondjump_p (insn
)
2455 && onlyjump_p (insn
))
2456 || GET_CODE (PATTERN (insn
)) == RETURN
)
2457 && (next
= NEXT_INSN (insn
))
2458 && GET_CODE (next
) == BARRIER
);
2461 /* Don't chain through the insn that jumps into a loop
2462 from outside the loop,
2463 since that would create multiple loop entry jumps
2464 and prevent loop optimization. */
2466 if (!reload_completed
)
2467 for (tem
= value
; tem
!= insn
; tem
= NEXT_INSN (tem
))
2468 if (GET_CODE (tem
) == NOTE
2469 && (NOTE_LINE_NUMBER (tem
) == NOTE_INSN_LOOP_BEG
2470 /* ??? Optional. Disables some optimizations, but makes
2471 gcov output more accurate with -O. */
2472 || (flag_test_coverage
&& NOTE_LINE_NUMBER (tem
) > 0)))
2475 /* If we have found a cycle, make the insn jump to itself. */
2476 if (JUMP_LABEL (insn
) == label
)
2479 tem
= next_active_insn (JUMP_LABEL (insn
));
2480 if (tem
&& (GET_CODE (PATTERN (tem
)) == ADDR_VEC
2481 || GET_CODE (PATTERN (tem
)) == ADDR_DIFF_VEC
))
2484 value
= JUMP_LABEL (insn
);
2491 /* Assuming that field IDX of X is a vector of label_refs,
2492 replace each of them by the ultimate label reached by it.
2493 Return nonzero if a change is made.
2494 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2497 tension_vector_labels (x
, idx
)
2503 for (i
= XVECLEN (x
, idx
) - 1; i
>= 0; i
--)
2505 register rtx olabel
= XEXP (XVECEXP (x
, idx
, i
), 0);
2506 register rtx nlabel
= follow_jumps (olabel
);
2507 if (nlabel
&& nlabel
!= olabel
)
2509 XEXP (XVECEXP (x
, idx
, i
), 0) = nlabel
;
2510 ++LABEL_NUSES (nlabel
);
2511 if (--LABEL_NUSES (olabel
) == 0)
2512 delete_insn (olabel
);
2519 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2520 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2521 in INSN, then store one of them in JUMP_LABEL (INSN).
2522 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2523 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2524 Also, when there are consecutive labels, canonicalize on the last of them.
2526 Note that two labels separated by a loop-beginning note
2527 must be kept distinct if we have not yet done loop-optimization,
2528 because the gap between them is where loop-optimize
2529 will want to move invariant code to. CROSS_JUMP tells us
2530 that loop-optimization is done with.
2532 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2533 two labels distinct if they are separated by only USE or CLOBBER insns. */
2536 mark_jump_label (x
, insn
, cross_jump
, in_mem
)
2542 register RTX_CODE code
= GET_CODE (x
);
2544 register const char *fmt
;
2566 /* If this is a constant-pool reference, see if it is a label. */
2567 if (CONSTANT_POOL_ADDRESS_P (x
))
2568 mark_jump_label (get_pool_constant (x
), insn
, cross_jump
, in_mem
);
2573 rtx label
= XEXP (x
, 0);
2577 /* Ignore remaining references to unreachable labels that
2578 have been deleted. */
2579 if (GET_CODE (label
) == NOTE
2580 && NOTE_LINE_NUMBER (label
) == NOTE_INSN_DELETED_LABEL
)
2583 if (GET_CODE (label
) != CODE_LABEL
)
2586 /* Ignore references to labels of containing functions. */
2587 if (LABEL_REF_NONLOCAL_P (x
))
2590 /* If there are other labels following this one,
2591 replace it with the last of the consecutive labels. */
2592 for (next
= NEXT_INSN (label
); next
; next
= NEXT_INSN (next
))
2594 if (GET_CODE (next
) == CODE_LABEL
)
2596 else if (cross_jump
&& GET_CODE (next
) == INSN
2597 && (GET_CODE (PATTERN (next
)) == USE
2598 || GET_CODE (PATTERN (next
)) == CLOBBER
))
2600 else if (GET_CODE (next
) != NOTE
)
2602 else if (! cross_jump
2603 && (NOTE_LINE_NUMBER (next
) == NOTE_INSN_LOOP_BEG
2604 || NOTE_LINE_NUMBER (next
) == NOTE_INSN_FUNCTION_END
2605 /* ??? Optional. Disables some optimizations, but
2606 makes gcov output more accurate with -O. */
2607 || (flag_test_coverage
2608 && NOTE_LINE_NUMBER (next
) > 0)))
2612 XEXP (x
, 0) = label
;
2613 if (! insn
|| ! INSN_DELETED_P (insn
))
2614 ++LABEL_NUSES (label
);
2618 if (GET_CODE (insn
) == JUMP_INSN
)
2619 JUMP_LABEL (insn
) = label
;
2621 /* If we've changed the label, update notes accordingly. */
2622 else if (label
!= olabel
)
2626 /* We may have a REG_LABEL note to indicate that this
2627 instruction uses the label. */
2628 note
= find_reg_note (insn
, REG_LABEL
, olabel
);
2630 XEXP (note
, 0) = label
;
2632 /* We may also have a REG_EQUAL note to indicate that
2633 a register is being set to the address of the
2635 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
2637 && GET_CODE (XEXP (note
, 0)) == LABEL_REF
2638 && XEXP (XEXP (note
, 0), 0) == olabel
)
2639 XEXP (XEXP (note
, 0), 0) = label
;
2642 /* Otherwise, add a REG_LABEL note for LABEL unless there already
2644 else if (! find_reg_note (insn
, REG_LABEL
, label
))
2646 /* This code used to ignore labels which refered to dispatch
2647 tables to avoid flow.c generating worse code.
2649 However, in the presense of global optimizations like
2650 gcse which call find_basic_blocks without calling
2651 life_analysis, not recording such labels will lead
2652 to compiler aborts because of inconsistencies in the
2653 flow graph. So we go ahead and record the label.
2655 It may also be the case that the optimization argument
2656 is no longer valid because of the more accurate cfg
2657 we build in find_basic_blocks -- it no longer pessimizes
2658 code when it finds a REG_LABEL note. */
2659 REG_NOTES (insn
) = gen_rtx_INSN_LIST (REG_LABEL
, label
,
2666 /* Do walk the labels in a vector, but not the first operand of an
2667 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2670 if (! INSN_DELETED_P (insn
))
2672 int eltnum
= code
== ADDR_DIFF_VEC
? 1 : 0;
2674 for (i
= 0; i
< XVECLEN (x
, eltnum
); i
++)
2675 mark_jump_label (XVECEXP (x
, eltnum
, i
), NULL_RTX
,
2676 cross_jump
, in_mem
);
2684 fmt
= GET_RTX_FORMAT (code
);
2685 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
2688 mark_jump_label (XEXP (x
, i
), insn
, cross_jump
, in_mem
);
2689 else if (fmt
[i
] == 'E')
2692 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
2693 mark_jump_label (XVECEXP (x
, i
, j
), insn
, cross_jump
, in_mem
);
2698 /* If all INSN does is set the pc, delete it,
2699 and delete the insn that set the condition codes for it
2700 if that's what the previous thing was. */
2706 register rtx set
= single_set (insn
);
2708 if (set
&& GET_CODE (SET_DEST (set
)) == PC
)
2709 delete_computation (insn
);
2712 /* Verify INSN is a BARRIER and delete it. */
2715 delete_barrier (insn
)
2718 if (GET_CODE (insn
) != BARRIER
)
2724 /* Recursively delete prior insns that compute the value (used only by INSN
2725 which the caller is deleting) stored in the register mentioned by NOTE
2726 which is a REG_DEAD note associated with INSN. */
2729 delete_prior_computation (note
, insn
)
2734 rtx reg
= XEXP (note
, 0);
2736 for (our_prev
= prev_nonnote_insn (insn
);
2737 our_prev
&& (GET_CODE (our_prev
) == INSN
2738 || GET_CODE (our_prev
) == CALL_INSN
);
2739 our_prev
= prev_nonnote_insn (our_prev
))
2741 rtx pat
= PATTERN (our_prev
);
2743 /* If we reach a CALL which is not calling a const function
2744 or the callee pops the arguments, then give up. */
2745 if (GET_CODE (our_prev
) == CALL_INSN
2746 && (! CONST_CALL_P (our_prev
)
2747 || GET_CODE (pat
) != SET
|| GET_CODE (SET_SRC (pat
)) != CALL
))
2750 /* If we reach a SEQUENCE, it is too complex to try to
2751 do anything with it, so give up. */
2752 if (GET_CODE (pat
) == SEQUENCE
)
2755 if (GET_CODE (pat
) == USE
2756 && GET_CODE (XEXP (pat
, 0)) == INSN
)
2757 /* reorg creates USEs that look like this. We leave them
2758 alone because reorg needs them for its own purposes. */
2761 if (reg_set_p (reg
, pat
))
2763 if (side_effects_p (pat
) && GET_CODE (our_prev
) != CALL_INSN
)
2766 if (GET_CODE (pat
) == PARALLEL
)
2768 /* If we find a SET of something else, we can't
2773 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
2775 rtx part
= XVECEXP (pat
, 0, i
);
2777 if (GET_CODE (part
) == SET
2778 && SET_DEST (part
) != reg
)
2782 if (i
== XVECLEN (pat
, 0))
2783 delete_computation (our_prev
);
2785 else if (GET_CODE (pat
) == SET
2786 && GET_CODE (SET_DEST (pat
)) == REG
)
2788 int dest_regno
= REGNO (SET_DEST (pat
));
2791 + (dest_regno
< FIRST_PSEUDO_REGISTER
2792 ? HARD_REGNO_NREGS (dest_regno
,
2793 GET_MODE (SET_DEST (pat
))) : 1));
2794 int regno
= REGNO (reg
);
2797 + (regno
< FIRST_PSEUDO_REGISTER
2798 ? HARD_REGNO_NREGS (regno
, GET_MODE (reg
)) : 1));
2800 if (dest_regno
>= regno
2801 && dest_endregno
<= endregno
)
2802 delete_computation (our_prev
);
2804 /* We may have a multi-word hard register and some, but not
2805 all, of the words of the register are needed in subsequent
2806 insns. Write REG_UNUSED notes for those parts that were not
2808 else if (dest_regno
<= regno
2809 && dest_endregno
>= endregno
)
2813 REG_NOTES (our_prev
)
2814 = gen_rtx_EXPR_LIST (REG_UNUSED
, reg
,
2815 REG_NOTES (our_prev
));
2817 for (i
= dest_regno
; i
< dest_endregno
; i
++)
2818 if (! find_regno_note (our_prev
, REG_UNUSED
, i
))
2821 if (i
== dest_endregno
)
2822 delete_computation (our_prev
);
2829 /* If PAT references the register that dies here, it is an
2830 additional use. Hence any prior SET isn't dead. However, this
2831 insn becomes the new place for the REG_DEAD note. */
2832 if (reg_overlap_mentioned_p (reg
, pat
))
2834 XEXP (note
, 1) = REG_NOTES (our_prev
);
2835 REG_NOTES (our_prev
) = note
;
2841 /* Delete INSN and recursively delete insns that compute values used only
2842 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2843 If we are running before flow.c, we need do nothing since flow.c will
2844 delete dead code. We also can't know if the registers being used are
2845 dead or not at this point.
2847 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2848 nothing other than set a register that dies in this insn, we can delete
2851 On machines with CC0, if CC0 is used in this insn, we may be able to
2852 delete the insn that set it. */
2855 delete_computation (insn
)
2861 if (reg_referenced_p (cc0_rtx
, PATTERN (insn
)))
2863 rtx prev
= prev_nonnote_insn (insn
);
2864 /* We assume that at this stage
2865 CC's are always set explicitly
2866 and always immediately before the jump that
2867 will use them. So if the previous insn
2868 exists to set the CC's, delete it
2869 (unless it performs auto-increments, etc.). */
2870 if (prev
&& GET_CODE (prev
) == INSN
2871 && sets_cc0_p (PATTERN (prev
)))
2873 if (sets_cc0_p (PATTERN (prev
)) > 0
2874 && ! side_effects_p (PATTERN (prev
)))
2875 delete_computation (prev
);
2877 /* Otherwise, show that cc0 won't be used. */
2878 REG_NOTES (prev
) = gen_rtx_EXPR_LIST (REG_UNUSED
,
2879 cc0_rtx
, REG_NOTES (prev
));
2884 for (note
= REG_NOTES (insn
); note
; note
= next
)
2886 next
= XEXP (note
, 1);
2888 if (REG_NOTE_KIND (note
) != REG_DEAD
2889 /* Verify that the REG_NOTE is legitimate. */
2890 || GET_CODE (XEXP (note
, 0)) != REG
)
2893 delete_prior_computation (note
, insn
);
2899 /* Delete insn INSN from the chain of insns and update label ref counts.
2900 May delete some following insns as a consequence; may even delete
2901 a label elsewhere and insns that follow it.
2903 Returns the first insn after INSN that was not deleted. */
2909 register rtx next
= NEXT_INSN (insn
);
2910 register rtx prev
= PREV_INSN (insn
);
2911 register int was_code_label
= (GET_CODE (insn
) == CODE_LABEL
);
2912 register int dont_really_delete
= 0;
2915 while (next
&& INSN_DELETED_P (next
))
2916 next
= NEXT_INSN (next
);
2918 /* This insn is already deleted => return first following nondeleted. */
2919 if (INSN_DELETED_P (insn
))
2923 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
2925 /* Don't delete user-declared labels. When optimizing, convert them
2926 to special NOTEs instead. When not optimizing, leave them alone. */
2927 if (was_code_label
&& LABEL_NAME (insn
) != 0)
2931 const char *name
= LABEL_NAME (insn
);
2932 PUT_CODE (insn
, NOTE
);
2933 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED_LABEL
;
2934 NOTE_SOURCE_FILE (insn
) = name
;
2937 dont_really_delete
= 1;
2940 /* Mark this insn as deleted. */
2941 INSN_DELETED_P (insn
) = 1;
2943 /* If this is an unconditional jump, delete it from the jump chain. */
2944 if (simplejump_p (insn
))
2945 delete_from_jump_chain (insn
);
2947 /* If instruction is followed by a barrier,
2948 delete the barrier too. */
2950 if (next
!= 0 && GET_CODE (next
) == BARRIER
)
2952 INSN_DELETED_P (next
) = 1;
2953 next
= NEXT_INSN (next
);
2956 /* Patch out INSN (and the barrier if any) */
2958 if (! dont_really_delete
)
2962 NEXT_INSN (prev
) = next
;
2963 if (GET_CODE (prev
) == INSN
&& GET_CODE (PATTERN (prev
)) == SEQUENCE
)
2964 NEXT_INSN (XVECEXP (PATTERN (prev
), 0,
2965 XVECLEN (PATTERN (prev
), 0) - 1)) = next
;
2970 PREV_INSN (next
) = prev
;
2971 if (GET_CODE (next
) == INSN
&& GET_CODE (PATTERN (next
)) == SEQUENCE
)
2972 PREV_INSN (XVECEXP (PATTERN (next
), 0, 0)) = prev
;
2975 if (prev
&& NEXT_INSN (prev
) == 0)
2976 set_last_insn (prev
);
2979 /* If deleting a jump, decrement the count of the label,
2980 and delete the label if it is now unused. */
2982 if (GET_CODE (insn
) == JUMP_INSN
&& JUMP_LABEL (insn
))
2984 rtx lab
= JUMP_LABEL (insn
), lab_next
;
2986 if (--LABEL_NUSES (lab
) == 0)
2988 /* This can delete NEXT or PREV,
2989 either directly if NEXT is JUMP_LABEL (INSN),
2990 or indirectly through more levels of jumps. */
2993 /* I feel a little doubtful about this loop,
2994 but I see no clean and sure alternative way
2995 to find the first insn after INSN that is not now deleted.
2996 I hope this works. */
2997 while (next
&& INSN_DELETED_P (next
))
2998 next
= NEXT_INSN (next
);
3001 else if ((lab_next
= next_nonnote_insn (lab
)) != NULL
3002 && GET_CODE (lab_next
) == JUMP_INSN
3003 && (GET_CODE (PATTERN (lab_next
)) == ADDR_VEC
3004 || GET_CODE (PATTERN (lab_next
)) == ADDR_DIFF_VEC
))
3006 /* If we're deleting the tablejump, delete the dispatch table.
3007 We may not be able to kill the label immediately preceeding
3008 just yet, as it might be referenced in code leading up to
3010 delete_insn (lab_next
);
3014 /* Likewise if we're deleting a dispatch table. */
3016 if (GET_CODE (insn
) == JUMP_INSN
3017 && (GET_CODE (PATTERN (insn
)) == ADDR_VEC
3018 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
))
3020 rtx pat
= PATTERN (insn
);
3021 int i
, diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
3022 int len
= XVECLEN (pat
, diff_vec_p
);
3024 for (i
= 0; i
< len
; i
++)
3025 if (--LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)) == 0)
3026 delete_insn (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0));
3027 while (next
&& INSN_DELETED_P (next
))
3028 next
= NEXT_INSN (next
);
3032 /* Likewise for an ordinary INSN / CALL_INSN with a REG_LABEL note. */
3033 if (GET_CODE (insn
) == INSN
|| GET_CODE (insn
) == CALL_INSN
)
3034 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
3035 if (REG_NOTE_KIND (note
) == REG_LABEL
3036 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
3037 && GET_CODE (XEXP (note
, 0)) == CODE_LABEL
)
3038 if (--LABEL_NUSES (XEXP (note
, 0)) == 0)
3039 delete_insn (XEXP (note
, 0));
3041 while (prev
&& (INSN_DELETED_P (prev
) || GET_CODE (prev
) == NOTE
))
3042 prev
= PREV_INSN (prev
);
3044 /* If INSN was a label and a dispatch table follows it,
3045 delete the dispatch table. The tablejump must have gone already.
3046 It isn't useful to fall through into a table. */
3049 && NEXT_INSN (insn
) != 0
3050 && GET_CODE (NEXT_INSN (insn
)) == JUMP_INSN
3051 && (GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_VEC
3052 || GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_DIFF_VEC
))
3053 next
= delete_insn (NEXT_INSN (insn
));
3055 /* If INSN was a label, delete insns following it if now unreachable. */
3057 if (was_code_label
&& prev
&& GET_CODE (prev
) == BARRIER
)
3059 register RTX_CODE code
;
3061 && (GET_RTX_CLASS (code
= GET_CODE (next
)) == 'i'
3062 || code
== NOTE
|| code
== BARRIER
3063 || (code
== CODE_LABEL
&& INSN_DELETED_P (next
))))
3066 && NOTE_LINE_NUMBER (next
) != NOTE_INSN_FUNCTION_END
)
3067 next
= NEXT_INSN (next
);
3068 /* Keep going past other deleted labels to delete what follows. */
3069 else if (code
== CODE_LABEL
&& INSN_DELETED_P (next
))
3070 next
= NEXT_INSN (next
);
3072 /* Note: if this deletes a jump, it can cause more
3073 deletion of unreachable code, after a different label.
3074 As long as the value from this recursive call is correct,
3075 this invocation functions correctly. */
3076 next
= delete_insn (next
);
3083 /* Advance from INSN till reaching something not deleted
3084 then return that. May return INSN itself. */
3087 next_nondeleted_insn (insn
)
3090 while (INSN_DELETED_P (insn
))
3091 insn
= NEXT_INSN (insn
);
3095 /* Delete a range of insns from FROM to TO, inclusive.
3096 This is for the sake of peephole optimization, so assume
3097 that whatever these insns do will still be done by a new
3098 peephole insn that will replace them. */
3101 delete_for_peephole (from
, to
)
3102 register rtx from
, to
;
3104 register rtx insn
= from
;
3108 register rtx next
= NEXT_INSN (insn
);
3109 register rtx prev
= PREV_INSN (insn
);
3111 if (GET_CODE (insn
) != NOTE
)
3113 INSN_DELETED_P (insn
) = 1;
3115 /* Patch this insn out of the chain. */
3116 /* We don't do this all at once, because we
3117 must preserve all NOTEs. */
3119 NEXT_INSN (prev
) = next
;
3122 PREV_INSN (next
) = prev
;
3130 /* Note that if TO is an unconditional jump
3131 we *do not* delete the BARRIER that follows,
3132 since the peephole that replaces this sequence
3133 is also an unconditional jump in that case. */
3136 /* We have determined that INSN is never reached, and are about to
3137 delete it. Print a warning if the user asked for one.
3139 To try to make this warning more useful, this should only be called
3140 once per basic block not reached, and it only warns when the basic
3141 block contains more than one line from the current function, and
3142 contains at least one operation. CSE and inlining can duplicate insns,
3143 so it's possible to get spurious warnings from this. */
3146 never_reached_warning (avoided_insn
)
3150 rtx a_line_note
= NULL
;
3151 int two_avoided_lines
= 0;
3152 int contains_insn
= 0;
3154 if (! warn_notreached
)
3157 /* Scan forwards, looking at LINE_NUMBER notes, until
3158 we hit a LABEL or we run out of insns. */
3160 for (insn
= avoided_insn
; insn
!= NULL
; insn
= NEXT_INSN (insn
))
3162 if (GET_CODE (insn
) == CODE_LABEL
)
3164 else if (GET_CODE (insn
) == NOTE
/* A line number note? */
3165 && NOTE_LINE_NUMBER (insn
) >= 0)
3167 if (a_line_note
== NULL
)
3170 two_avoided_lines
|= (NOTE_LINE_NUMBER (a_line_note
)
3171 != NOTE_LINE_NUMBER (insn
));
3173 else if (INSN_P (insn
))
3176 if (two_avoided_lines
&& contains_insn
)
3177 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note
),
3178 NOTE_LINE_NUMBER (a_line_note
),
3179 "will never be executed");
3182 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
3183 NLABEL as a return. Accrue modifications into the change group. */
3186 redirect_exp_1 (loc
, olabel
, nlabel
, insn
)
3191 register rtx x
= *loc
;
3192 register RTX_CODE code
= GET_CODE (x
);
3194 register const char *fmt
;
3196 if (code
== LABEL_REF
)
3198 if (XEXP (x
, 0) == olabel
)
3202 n
= gen_rtx_LABEL_REF (VOIDmode
, nlabel
);
3204 n
= gen_rtx_RETURN (VOIDmode
);
3206 validate_change (insn
, loc
, n
, 1);
3210 else if (code
== RETURN
&& olabel
== 0)
3212 x
= gen_rtx_LABEL_REF (VOIDmode
, nlabel
);
3213 if (loc
== &PATTERN (insn
))
3214 x
= gen_rtx_SET (VOIDmode
, pc_rtx
, x
);
3215 validate_change (insn
, loc
, x
, 1);
3219 if (code
== SET
&& nlabel
== 0 && SET_DEST (x
) == pc_rtx
3220 && GET_CODE (SET_SRC (x
)) == LABEL_REF
3221 && XEXP (SET_SRC (x
), 0) == olabel
)
3223 validate_change (insn
, loc
, gen_rtx_RETURN (VOIDmode
), 1);
3227 fmt
= GET_RTX_FORMAT (code
);
3228 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3231 redirect_exp_1 (&XEXP (x
, i
), olabel
, nlabel
, insn
);
3232 else if (fmt
[i
] == 'E')
3235 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3236 redirect_exp_1 (&XVECEXP (x
, i
, j
), olabel
, nlabel
, insn
);
3241 /* Similar, but apply the change group and report success or failure. */
3244 redirect_exp (olabel
, nlabel
, insn
)
3250 if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
3251 loc
= &XVECEXP (PATTERN (insn
), 0, 0);
3253 loc
= &PATTERN (insn
);
3255 redirect_exp_1 (loc
, olabel
, nlabel
, insn
);
3256 if (num_validated_changes () == 0)
3259 return apply_change_group ();
3262 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3263 the modifications into the change group. Return false if we did
3264 not see how to do that. */
3267 redirect_jump_1 (jump
, nlabel
)
3270 int ochanges
= num_validated_changes ();
3273 if (GET_CODE (PATTERN (jump
)) == PARALLEL
)
3274 loc
= &XVECEXP (PATTERN (jump
), 0, 0);
3276 loc
= &PATTERN (jump
);
3278 redirect_exp_1 (loc
, JUMP_LABEL (jump
), nlabel
, jump
);
3279 return num_validated_changes () > ochanges
;
3282 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3283 jump target label is unused as a result, it and the code following
3286 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3289 The return value will be 1 if the change was made, 0 if it wasn't
3290 (this can only occur for NLABEL == 0). */
3293 redirect_jump (jump
, nlabel
, delete_unused
)
3297 register rtx olabel
= JUMP_LABEL (jump
);
3299 if (nlabel
== olabel
)
3302 if (! redirect_exp (olabel
, nlabel
, jump
))
3305 /* If this is an unconditional branch, delete it from the jump_chain of
3306 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3307 have UID's in range and JUMP_CHAIN is valid). */
3308 if (jump_chain
&& (simplejump_p (jump
)
3309 || GET_CODE (PATTERN (jump
)) == RETURN
))
3311 int label_index
= nlabel
? INSN_UID (nlabel
) : 0;
3313 delete_from_jump_chain (jump
);
3314 if (label_index
< max_jump_chain
3315 && INSN_UID (jump
) < max_jump_chain
)
3317 jump_chain
[INSN_UID (jump
)] = jump_chain
[label_index
];
3318 jump_chain
[label_index
] = jump
;
3322 JUMP_LABEL (jump
) = nlabel
;
3324 ++LABEL_NUSES (nlabel
);
3326 /* If we're eliding the jump over exception cleanups at the end of a
3327 function, move the function end note so that -Wreturn-type works. */
3328 if (olabel
&& nlabel
3329 && NEXT_INSN (olabel
)
3330 && GET_CODE (NEXT_INSN (olabel
)) == NOTE
3331 && NOTE_LINE_NUMBER (NEXT_INSN (olabel
)) == NOTE_INSN_FUNCTION_END
)
3332 emit_note_after (NOTE_INSN_FUNCTION_END
, nlabel
);
3334 if (olabel
&& --LABEL_NUSES (olabel
) == 0 && delete_unused
)
3335 delete_insn (olabel
);
3340 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3341 Accrue the modifications into the change group. */
3347 register RTX_CODE code
;
3348 rtx x
= pc_set (insn
);
3354 code
= GET_CODE (x
);
3356 if (code
== IF_THEN_ELSE
)
3358 register rtx comp
= XEXP (x
, 0);
3360 enum rtx_code reversed_code
;
3362 /* We can do this in two ways: The preferable way, which can only
3363 be done if this is not an integer comparison, is to reverse
3364 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3365 of the IF_THEN_ELSE. If we can't do either, fail. */
3367 reversed_code
= reversed_comparison_code (comp
, insn
);
3369 if (reversed_code
!= UNKNOWN
)
3371 validate_change (insn
, &XEXP (x
, 0),
3372 gen_rtx_fmt_ee (reversed_code
,
3373 GET_MODE (comp
), XEXP (comp
, 0),
3380 validate_change (insn
, &XEXP (x
, 1), XEXP (x
, 2), 1);
3381 validate_change (insn
, &XEXP (x
, 2), tem
, 1);
3387 /* Invert the jump condition of conditional jump insn, INSN.
3389 Return 1 if we can do so, 0 if we cannot find a way to do so that
3390 matches a pattern. */
3396 invert_exp_1 (insn
);
3397 if (num_validated_changes () == 0)
3400 return apply_change_group ();
3403 /* Invert the condition of the jump JUMP, and make it jump to label
3404 NLABEL instead of where it jumps now. Accrue changes into the
3405 change group. Return false if we didn't see how to perform the
3406 inversion and redirection. */
3409 invert_jump_1 (jump
, nlabel
)
3414 ochanges
= num_validated_changes ();
3415 invert_exp_1 (jump
);
3416 if (num_validated_changes () == ochanges
)
3419 return redirect_jump_1 (jump
, nlabel
);
3422 /* Invert the condition of the jump JUMP, and make it jump to label
3423 NLABEL instead of where it jumps now. Return true if successful. */
3426 invert_jump (jump
, nlabel
, delete_unused
)
3430 /* We have to either invert the condition and change the label or
3431 do neither. Either operation could fail. We first try to invert
3432 the jump. If that succeeds, we try changing the label. If that fails,
3433 we invert the jump back to what it was. */
3435 if (! invert_exp (jump
))
3438 if (redirect_jump (jump
, nlabel
, delete_unused
))
3440 /* An inverted jump means that a probability taken becomes a
3441 probability not taken. Subtract the branch probability from the
3442 probability base to convert it back to a taken probability. */
3444 rtx note
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
3446 XEXP (note
, 0) = GEN_INT (REG_BR_PROB_BASE
- INTVAL (XEXP (note
, 0)));
3451 if (! invert_exp (jump
))
3452 /* This should just be putting it back the way it was. */
3458 /* Delete the instruction JUMP from any jump chain it might be on. */
3461 delete_from_jump_chain (jump
)
3465 rtx olabel
= JUMP_LABEL (jump
);
3467 /* Handle unconditional jumps. */
3468 if (jump_chain
&& olabel
!= 0
3469 && INSN_UID (olabel
) < max_jump_chain
3470 && simplejump_p (jump
))
3471 index
= INSN_UID (olabel
);
3472 /* Handle return insns. */
3473 else if (jump_chain
&& GET_CODE (PATTERN (jump
)) == RETURN
)
3478 if (jump_chain
[index
] == jump
)
3479 jump_chain
[index
] = jump_chain
[INSN_UID (jump
)];
3484 for (insn
= jump_chain
[index
];
3486 insn
= jump_chain
[INSN_UID (insn
)])
3487 if (jump_chain
[INSN_UID (insn
)] == jump
)
3489 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (jump
)];
3495 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3497 If the old jump target label (before the dispatch table) becomes unused,
3498 it and the dispatch table may be deleted. In that case, find the insn
3499 before the jump references that label and delete it and logical successors
3503 redirect_tablejump (jump
, nlabel
)
3506 register rtx olabel
= JUMP_LABEL (jump
);
3507 rtx
*notep
, note
, next
;
3509 /* Add this jump to the jump_chain of NLABEL. */
3510 if (jump_chain
&& INSN_UID (nlabel
) < max_jump_chain
3511 && INSN_UID (jump
) < max_jump_chain
)
3513 jump_chain
[INSN_UID (jump
)] = jump_chain
[INSN_UID (nlabel
)];
3514 jump_chain
[INSN_UID (nlabel
)] = jump
;
3517 for (notep
= ®_NOTES (jump
), note
= *notep
; note
; note
= next
)
3519 next
= XEXP (note
, 1);
3521 if (REG_NOTE_KIND (note
) != REG_DEAD
3522 /* Verify that the REG_NOTE is legitimate. */
3523 || GET_CODE (XEXP (note
, 0)) != REG
3524 || ! reg_mentioned_p (XEXP (note
, 0), PATTERN (jump
)))
3525 notep
= &XEXP (note
, 1);
3528 delete_prior_computation (note
, jump
);
3533 PATTERN (jump
) = gen_jump (nlabel
);
3534 JUMP_LABEL (jump
) = nlabel
;
3535 ++LABEL_NUSES (nlabel
);
3536 INSN_CODE (jump
) = -1;
3538 if (--LABEL_NUSES (olabel
) == 0)
3540 delete_labelref_insn (jump
, olabel
, 0);
3541 delete_insn (olabel
);
3545 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3546 If we found one, delete it and then delete this insn if DELETE_THIS is
3547 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3550 delete_labelref_insn (insn
, label
, delete_this
)
3557 if (GET_CODE (insn
) != NOTE
3558 && reg_mentioned_p (label
, PATTERN (insn
)))
3569 for (link
= LOG_LINKS (insn
); link
; link
= XEXP (link
, 1))
3570 if (delete_labelref_insn (XEXP (link
, 0), label
, 1))
3584 /* Like rtx_equal_p except that it considers two REGs as equal
3585 if they renumber to the same value and considers two commutative
3586 operations to be the same if the order of the operands has been
3589 ??? Addition is not commutative on the PA due to the weird implicit
3590 space register selection rules for memory addresses. Therefore, we
3591 don't consider a + b == b + a.
3593 We could/should make this test a little tighter. Possibly only
3594 disabling it on the PA via some backend macro or only disabling this
3595 case when the PLUS is inside a MEM. */
3598 rtx_renumbered_equal_p (x
, y
)
3602 register RTX_CODE code
= GET_CODE (x
);
3603 register const char *fmt
;
3608 if ((code
== REG
|| (code
== SUBREG
&& GET_CODE (SUBREG_REG (x
)) == REG
))
3609 && (GET_CODE (y
) == REG
|| (GET_CODE (y
) == SUBREG
3610 && GET_CODE (SUBREG_REG (y
)) == REG
)))
3612 int reg_x
= -1, reg_y
= -1;
3613 int word_x
= 0, word_y
= 0;
3615 if (GET_MODE (x
) != GET_MODE (y
))
3618 /* If we haven't done any renumbering, don't
3619 make any assumptions. */
3620 if (reg_renumber
== 0)
3621 return rtx_equal_p (x
, y
);
3625 reg_x
= REGNO (SUBREG_REG (x
));
3626 word_x
= SUBREG_WORD (x
);
3628 if (reg_renumber
[reg_x
] >= 0)
3630 reg_x
= reg_renumber
[reg_x
] + word_x
;
3638 if (reg_renumber
[reg_x
] >= 0)
3639 reg_x
= reg_renumber
[reg_x
];
3642 if (GET_CODE (y
) == SUBREG
)
3644 reg_y
= REGNO (SUBREG_REG (y
));
3645 word_y
= SUBREG_WORD (y
);
3647 if (reg_renumber
[reg_y
] >= 0)
3649 reg_y
= reg_renumber
[reg_y
];
3657 if (reg_renumber
[reg_y
] >= 0)
3658 reg_y
= reg_renumber
[reg_y
];
3661 return reg_x
>= 0 && reg_x
== reg_y
&& word_x
== word_y
;
3664 /* Now we have disposed of all the cases
3665 in which different rtx codes can match. */
3666 if (code
!= GET_CODE (y
))
3678 return INTVAL (x
) == INTVAL (y
);
3681 /* We can't assume nonlocal labels have their following insns yet. */
3682 if (LABEL_REF_NONLOCAL_P (x
) || LABEL_REF_NONLOCAL_P (y
))
3683 return XEXP (x
, 0) == XEXP (y
, 0);
3685 /* Two label-refs are equivalent if they point at labels
3686 in the same position in the instruction stream. */
3687 return (next_real_insn (XEXP (x
, 0))
3688 == next_real_insn (XEXP (y
, 0)));
3691 return XSTR (x
, 0) == XSTR (y
, 0);
3694 /* If we didn't match EQ equality above, they aren't the same. */
3701 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3703 if (GET_MODE (x
) != GET_MODE (y
))
3706 /* For commutative operations, the RTX match if the operand match in any
3707 order. Also handle the simple binary and unary cases without a loop.
3709 ??? Don't consider PLUS a commutative operator; see comments above. */
3710 if ((code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
3712 return ((rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
3713 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)))
3714 || (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 1))
3715 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 0))));
3716 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
3717 return (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
3718 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)));
3719 else if (GET_RTX_CLASS (code
) == '1')
3720 return rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0));
3722 /* Compare the elements. If any pair of corresponding elements
3723 fail to match, return 0 for the whole things. */
3725 fmt
= GET_RTX_FORMAT (code
);
3726 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3732 if (XWINT (x
, i
) != XWINT (y
, i
))
3737 if (XINT (x
, i
) != XINT (y
, i
))
3742 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
3747 if (! rtx_renumbered_equal_p (XEXP (x
, i
), XEXP (y
, i
)))
3752 if (XEXP (x
, i
) != XEXP (y
, i
))
3759 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
3761 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
3762 if (!rtx_renumbered_equal_p (XVECEXP (x
, i
, j
), XVECEXP (y
, i
, j
)))
3773 /* If X is a hard register or equivalent to one or a subregister of one,
3774 return the hard register number. If X is a pseudo register that was not
3775 assigned a hard register, return the pseudo register number. Otherwise,
3776 return -1. Any rtx is valid for X. */
3782 if (GET_CODE (x
) == REG
)
3784 if (REGNO (x
) >= FIRST_PSEUDO_REGISTER
&& reg_renumber
[REGNO (x
)] >= 0)
3785 return reg_renumber
[REGNO (x
)];
3788 if (GET_CODE (x
) == SUBREG
)
3790 int base
= true_regnum (SUBREG_REG (x
));
3791 if (base
>= 0 && base
< FIRST_PSEUDO_REGISTER
)
3792 return SUBREG_WORD (x
) + base
;
3797 /* Optimize code of the form:
3799 for (x = a[i]; x; ...)
3801 for (x = a[i]; x; ...)
3805 Loop optimize will change the above code into
3809 { ...; if (! (x = ...)) break; }
3812 { ...; if (! (x = ...)) break; }
3815 In general, if the first test fails, the program can branch
3816 directly to `foo' and skip the second try which is doomed to fail.
3817 We run this after loop optimization and before flow analysis. */
3819 /* When comparing the insn patterns, we track the fact that different
3820 pseudo-register numbers may have been used in each computation.
3821 The following array stores an equivalence -- same_regs[I] == J means
3822 that pseudo register I was used in the first set of tests in a context
3823 where J was used in the second set. We also count the number of such
3824 pending equivalences. If nonzero, the expressions really aren't the
3827 static int *same_regs
;
3829 static int num_same_regs
;
3831 /* Track any registers modified between the target of the first jump and
3832 the second jump. They never compare equal. */
3834 static char *modified_regs
;
3836 /* Record if memory was modified. */
3838 static int modified_mem
;
3840 /* Called via note_stores on each insn between the target of the first
3841 branch and the second branch. It marks any changed registers. */
3844 mark_modified_reg (dest
, x
, data
)
3846 rtx x ATTRIBUTE_UNUSED
;
3847 void *data ATTRIBUTE_UNUSED
;
3852 if (GET_CODE (dest
) == SUBREG
)
3853 dest
= SUBREG_REG (dest
);
3855 if (GET_CODE (dest
) == MEM
)
3858 if (GET_CODE (dest
) != REG
)
3861 regno
= REGNO (dest
);
3862 if (regno
>= FIRST_PSEUDO_REGISTER
)
3863 modified_regs
[regno
] = 1;
3865 for (i
= 0; i
< HARD_REGNO_NREGS (regno
, GET_MODE (dest
)); i
++)
3866 modified_regs
[regno
+ i
] = 1;
3869 /* F is the first insn in the chain of insns. */
3872 thread_jumps (f
, max_reg
, flag_before_loop
)
3875 int flag_before_loop
;
3877 /* Basic algorithm is to find a conditional branch,
3878 the label it may branch to, and the branch after
3879 that label. If the two branches test the same condition,
3880 walk back from both branch paths until the insn patterns
3881 differ, or code labels are hit. If we make it back to
3882 the target of the first branch, then we know that the first branch
3883 will either always succeed or always fail depending on the relative
3884 senses of the two branches. So adjust the first branch accordingly
3887 rtx label
, b1
, b2
, t1
, t2
;
3888 enum rtx_code code1
, code2
;
3889 rtx b1op0
, b1op1
, b2op0
, b2op1
;
3893 enum rtx_code reversed_code1
, reversed_code2
;
3895 /* Allocate register tables and quick-reset table. */
3896 modified_regs
= (char *) xmalloc (max_reg
* sizeof (char));
3897 same_regs
= (int *) xmalloc (max_reg
* sizeof (int));
3898 all_reset
= (int *) xmalloc (max_reg
* sizeof (int));
3899 for (i
= 0; i
< max_reg
; i
++)
3906 for (b1
= f
; b1
; b1
= NEXT_INSN (b1
))
3911 /* Get to a candidate branch insn. */
3912 if (GET_CODE (b1
) != JUMP_INSN
3913 || ! any_condjump_p (b1
) || JUMP_LABEL (b1
) == 0)
3916 memset (modified_regs
, 0, max_reg
* sizeof (char));
3919 memcpy (same_regs
, all_reset
, max_reg
* sizeof (int));
3922 label
= JUMP_LABEL (b1
);
3924 /* Look for a branch after the target. Record any registers and
3925 memory modified between the target and the branch. Stop when we
3926 get to a label since we can't know what was changed there. */
3927 for (b2
= NEXT_INSN (label
); b2
; b2
= NEXT_INSN (b2
))
3929 if (GET_CODE (b2
) == CODE_LABEL
)
3932 else if (GET_CODE (b2
) == JUMP_INSN
)
3934 /* If this is an unconditional jump and is the only use of
3935 its target label, we can follow it. */
3936 if (any_uncondjump_p (b2
)
3938 && JUMP_LABEL (b2
) != 0
3939 && LABEL_NUSES (JUMP_LABEL (b2
)) == 1)
3941 b2
= JUMP_LABEL (b2
);
3948 if (GET_CODE (b2
) != CALL_INSN
&& GET_CODE (b2
) != INSN
)
3951 if (GET_CODE (b2
) == CALL_INSN
)
3954 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
3955 if (call_used_regs
[i
] && ! fixed_regs
[i
]
3956 && i
!= STACK_POINTER_REGNUM
3957 && i
!= FRAME_POINTER_REGNUM
3958 && i
!= HARD_FRAME_POINTER_REGNUM
3959 && i
!= ARG_POINTER_REGNUM
)
3960 modified_regs
[i
] = 1;
3963 note_stores (PATTERN (b2
), mark_modified_reg
, NULL
);
3966 /* Check the next candidate branch insn from the label
3969 || GET_CODE (b2
) != JUMP_INSN
3971 || !any_condjump_p (b2
)
3972 || !onlyjump_p (b2
))
3977 /* Get the comparison codes and operands, reversing the
3978 codes if appropriate. If we don't have comparison codes,
3979 we can't do anything. */
3980 b1op0
= XEXP (XEXP (SET_SRC (set
), 0), 0);
3981 b1op1
= XEXP (XEXP (SET_SRC (set
), 0), 1);
3982 code1
= GET_CODE (XEXP (SET_SRC (set
), 0));
3983 reversed_code1
= code1
;
3984 if (XEXP (SET_SRC (set
), 1) == pc_rtx
)
3985 code1
= reversed_comparison_code (XEXP (SET_SRC (set
), 0), b1
);
3987 reversed_code1
= reversed_comparison_code (XEXP (SET_SRC (set
), 0), b1
);
3989 b2op0
= XEXP (XEXP (SET_SRC (set2
), 0), 0);
3990 b2op1
= XEXP (XEXP (SET_SRC (set2
), 0), 1);
3991 code2
= GET_CODE (XEXP (SET_SRC (set2
), 0));
3992 reversed_code2
= code2
;
3993 if (XEXP (SET_SRC (set2
), 1) == pc_rtx
)
3994 code2
= reversed_comparison_code (XEXP (SET_SRC (set2
), 0), b2
);
3996 reversed_code2
= reversed_comparison_code (XEXP (SET_SRC (set2
), 0), b2
);
3998 /* If they test the same things and knowing that B1 branches
3999 tells us whether or not B2 branches, check if we
4000 can thread the branch. */
4001 if (rtx_equal_for_thread_p (b1op0
, b2op0
, b2
)
4002 && rtx_equal_for_thread_p (b1op1
, b2op1
, b2
)
4003 && (comparison_dominates_p (code1
, code2
)
4004 || comparison_dominates_p (code1
, reversed_code2
)))
4007 t1
= prev_nonnote_insn (b1
);
4008 t2
= prev_nonnote_insn (b2
);
4010 while (t1
!= 0 && t2
!= 0)
4014 /* We have reached the target of the first branch.
4015 If there are no pending register equivalents,
4016 we know that this branch will either always
4017 succeed (if the senses of the two branches are
4018 the same) or always fail (if not). */
4021 if (num_same_regs
!= 0)
4024 if (comparison_dominates_p (code1
, code2
))
4025 new_label
= JUMP_LABEL (b2
);
4027 new_label
= get_label_after (b2
);
4029 if (JUMP_LABEL (b1
) != new_label
)
4031 rtx prev
= PREV_INSN (new_label
);
4033 if (flag_before_loop
4034 && GET_CODE (prev
) == NOTE
4035 && NOTE_LINE_NUMBER (prev
) == NOTE_INSN_LOOP_BEG
)
4037 /* Don't thread to the loop label. If a loop
4038 label is reused, loop optimization will
4039 be disabled for that loop. */
4040 new_label
= gen_label_rtx ();
4041 emit_label_after (new_label
, PREV_INSN (prev
));
4043 changed
|= redirect_jump (b1
, new_label
, 1);
4048 /* If either of these is not a normal insn (it might be
4049 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
4050 have already been skipped above.) Similarly, fail
4051 if the insns are different. */
4052 if (GET_CODE (t1
) != INSN
|| GET_CODE (t2
) != INSN
4053 || recog_memoized (t1
) != recog_memoized (t2
)
4054 || ! rtx_equal_for_thread_p (PATTERN (t1
),
4058 t1
= prev_nonnote_insn (t1
);
4059 t2
= prev_nonnote_insn (t2
);
4066 free (modified_regs
);
4071 /* This is like RTX_EQUAL_P except that it knows about our handling of
4072 possibly equivalent registers and knows to consider volatile and
4073 modified objects as not equal.
4075 YINSN is the insn containing Y. */
4078 rtx_equal_for_thread_p (x
, y
, yinsn
)
4084 register enum rtx_code code
;
4085 register const char *fmt
;
4087 code
= GET_CODE (x
);
4088 /* Rtx's of different codes cannot be equal. */
4089 if (code
!= GET_CODE (y
))
4092 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
4093 (REG:SI x) and (REG:HI x) are NOT equivalent. */
4095 if (GET_MODE (x
) != GET_MODE (y
))
4098 /* For floating-point, consider everything unequal. This is a bit
4099 pessimistic, but this pass would only rarely do anything for FP
4101 if (TARGET_FLOAT_FORMAT
== IEEE_FLOAT_FORMAT
4102 && FLOAT_MODE_P (GET_MODE (x
)) && ! flag_fast_math
)
4105 /* For commutative operations, the RTX match if the operand match in any
4106 order. Also handle the simple binary and unary cases without a loop. */
4107 if (code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
4108 return ((rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
4109 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
))
4110 || (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 1), yinsn
)
4111 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 0), yinsn
)));
4112 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
4113 return (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
4114 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
));
4115 else if (GET_RTX_CLASS (code
) == '1')
4116 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
4118 /* Handle special-cases first. */
4122 if (REGNO (x
) == REGNO (y
) && ! modified_regs
[REGNO (x
)])
4125 /* If neither is user variable or hard register, check for possible
4127 if (REG_USERVAR_P (x
) || REG_USERVAR_P (y
)
4128 || REGNO (x
) < FIRST_PSEUDO_REGISTER
4129 || REGNO (y
) < FIRST_PSEUDO_REGISTER
)
4132 if (same_regs
[REGNO (x
)] == -1)
4134 same_regs
[REGNO (x
)] = REGNO (y
);
4137 /* If this is the first time we are seeing a register on the `Y'
4138 side, see if it is the last use. If not, we can't thread the
4139 jump, so mark it as not equivalent. */
4140 if (REGNO_LAST_UID (REGNO (y
)) != INSN_UID (yinsn
))
4146 return (same_regs
[REGNO (x
)] == (int) REGNO (y
));
4151 /* If memory modified or either volatile, not equivalent.
4152 Else, check address. */
4153 if (modified_mem
|| MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
4156 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
4159 if (MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
4165 /* Cancel a pending `same_regs' if setting equivalenced registers.
4166 Then process source. */
4167 if (GET_CODE (SET_DEST (x
)) == REG
4168 && GET_CODE (SET_DEST (y
)) == REG
)
4170 if (same_regs
[REGNO (SET_DEST (x
))] == (int) REGNO (SET_DEST (y
)))
4172 same_regs
[REGNO (SET_DEST (x
))] = -1;
4175 else if (REGNO (SET_DEST (x
)) != REGNO (SET_DEST (y
)))
4180 if (rtx_equal_for_thread_p (SET_DEST (x
), SET_DEST (y
), yinsn
) == 0)
4184 return rtx_equal_for_thread_p (SET_SRC (x
), SET_SRC (y
), yinsn
);
4187 return XEXP (x
, 0) == XEXP (y
, 0);
4190 return XSTR (x
, 0) == XSTR (y
, 0);
4199 fmt
= GET_RTX_FORMAT (code
);
4200 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4205 if (XWINT (x
, i
) != XWINT (y
, i
))
4211 if (XINT (x
, i
) != XINT (y
, i
))
4217 /* Two vectors must have the same length. */
4218 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
4221 /* And the corresponding elements must match. */
4222 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4223 if (rtx_equal_for_thread_p (XVECEXP (x
, i
, j
),
4224 XVECEXP (y
, i
, j
), yinsn
) == 0)
4229 if (rtx_equal_for_thread_p (XEXP (x
, i
), XEXP (y
, i
), yinsn
) == 0)
4235 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
4240 /* These are just backpointers, so they don't matter. */
4247 /* It is believed that rtx's at this level will never
4248 contain anything but integers and other rtx's,
4249 except for within LABEL_REFs and SYMBOL_REFs. */