1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 1998, 1999, 2000 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. */
23 /* This is the jump-optimization pass of the compiler.
24 It is run two or three times: once before cse, sometimes once after cse,
25 and once after reload (before final).
27 jump_optimize deletes unreachable code and labels that are not used.
28 It also deletes jumps that jump to the following insn,
29 and simplifies jumps around unconditional jumps and jumps
30 to unconditional jumps.
32 Each CODE_LABEL has a count of the times it is used
33 stored in the LABEL_NUSES internal field, and each JUMP_INSN
34 has one label that it refers to stored in the
35 JUMP_LABEL internal field. With this we can detect labels that
36 become unused because of the deletion of all the jumps that
37 formerly used them. The JUMP_LABEL info is sometimes looked
40 Optionally, cross-jumping can be done. Currently it is done
41 only the last time (when after reload and before final).
42 In fact, the code for cross-jumping now assumes that register
43 allocation has been done, since it uses `rtx_renumbered_equal_p'.
45 Jump optimization is done after cse when cse's constant-propagation
46 causes jumps to become unconditional or to be deleted.
48 Unreachable loops are not detected here, because the labels
49 have references and the insns appear reachable from the labels.
50 find_basic_blocks in flow.c finds and deletes such loops.
52 The subroutines delete_insn, redirect_jump, and invert_jump are used
53 from other passes as well. */
60 #include "hard-reg-set.h"
62 #include "insn-config.h"
63 #include "insn-flags.h"
64 #include "insn-attr.h"
72 /* ??? Eventually must record somehow the labels used by jumps
73 from nested functions. */
74 /* Pre-record the next or previous real insn for each label?
75 No, this pass is very fast anyway. */
76 /* Condense consecutive labels?
77 This would make life analysis faster, maybe. */
78 /* Optimize jump y; x: ... y: jumpif... x?
79 Don't know if it is worth bothering with. */
80 /* Optimize two cases of conditional jump to conditional jump?
81 This can never delete any instruction or make anything dead,
82 or even change what is live at any point.
83 So perhaps let combiner do it. */
85 /* Vector indexed by uid.
86 For each CODE_LABEL, index by its uid to get first unconditional jump
87 that jumps to the label.
88 For each JUMP_INSN, index by its uid to get the next unconditional jump
89 that jumps to the same label.
90 Element 0 is the start of a chain of all return insns.
91 (It is safe to use element 0 because insn uid 0 is not used. */
93 static rtx
*jump_chain
;
95 /* Maximum index in jump_chain. */
97 static int max_jump_chain
;
99 /* Set nonzero by jump_optimize if control can fall through
100 to the end of the function. */
103 /* Indicates whether death notes are significant in cross jump analysis.
104 Normally they are not significant, because of A and B jump to C,
105 and R dies in A, it must die in B. But this might not be true after
106 stack register conversion, and we must compare death notes in that
109 static int cross_jump_death_matters
= 0;
111 static int init_label_info
PARAMS ((rtx
));
112 static void delete_barrier_successors
PARAMS ((rtx
));
113 static void mark_all_labels
PARAMS ((rtx
, int));
114 static rtx delete_unreferenced_labels
PARAMS ((rtx
));
115 static void delete_noop_moves
PARAMS ((rtx
));
116 static int calculate_can_reach_end
PARAMS ((rtx
, int));
117 static int duplicate_loop_exit_test
PARAMS ((rtx
));
118 static void find_cross_jump
PARAMS ((rtx
, rtx
, int, rtx
*, rtx
*));
119 static void do_cross_jump
PARAMS ((rtx
, rtx
, rtx
));
120 static int jump_back_p
PARAMS ((rtx
, rtx
));
121 static int tension_vector_labels
PARAMS ((rtx
, int));
122 static void mark_jump_label
PARAMS ((rtx
, rtx
, int, int));
123 static void delete_computation
PARAMS ((rtx
));
124 static void redirect_exp_1
PARAMS ((rtx
*, rtx
, rtx
, rtx
));
125 static void invert_exp_1
PARAMS ((rtx
, rtx
));
126 static void delete_from_jump_chain
PARAMS ((rtx
));
127 static int delete_labelref_insn
PARAMS ((rtx
, rtx
, int));
128 static void mark_modified_reg
PARAMS ((rtx
, rtx
, void *));
129 static void redirect_tablejump
PARAMS ((rtx
, rtx
));
130 static void jump_optimize_1
PARAMS ((rtx
, int, int, int, int, int));
131 static int returnjump_p_1
PARAMS ((rtx
*, void *));
132 static void delete_prior_computation
PARAMS ((rtx
, rtx
));
134 /* Main external entry point into the jump optimizer. See comments before
135 jump_optimize_1 for descriptions of the arguments. */
137 jump_optimize (f
, cross_jump
, noop_moves
, after_regscan
)
143 jump_optimize_1 (f
, cross_jump
, noop_moves
, after_regscan
, 0, 0);
146 /* Alternate entry into the jump optimizer. This entry point only rebuilds
147 the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
150 rebuild_jump_labels (f
)
153 jump_optimize_1 (f
, 0, 0, 0, 1, 0);
156 /* Alternate entry into the jump optimizer. Do only trivial optimizations. */
158 jump_optimize_minimal (f
)
161 jump_optimize_1 (f
, 0, 0, 0, 0, 1);
164 /* Delete no-op jumps and optimize jumps to jumps
165 and jumps around jumps.
166 Delete unused labels and unreachable code.
168 If CROSS_JUMP is 1, detect matching code
169 before a jump and its destination and unify them.
170 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
172 If NOOP_MOVES is nonzero, delete no-op move insns.
174 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
175 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
177 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
178 and JUMP_LABEL field for jumping insns.
180 If `optimize' is zero, don't change any code,
181 just determine whether control drops off the end of the function.
182 This case occurs when we have -W and not -O.
183 It works because `delete_insn' checks the value of `optimize'
184 and refrains from actually deleting when that is 0.
186 If MINIMAL is nonzero, then we only perform trivial optimizations:
188 * Removal of unreachable code after BARRIERs.
189 * Removal of unreferenced CODE_LABELs.
190 * Removal of a jump to the next instruction.
191 * Removal of a conditional jump followed by an unconditional jump
192 to the same target as the conditional jump.
193 * Simplify a conditional jump around an unconditional jump.
194 * Simplify a jump to a jump.
195 * Delete extraneous line number notes.
199 jump_optimize_1 (f
, cross_jump
, noop_moves
, after_regscan
,
200 mark_labels_only
, minimal
)
205 int mark_labels_only
;
208 register rtx insn
, next
;
215 cross_jump_death_matters
= (cross_jump
== 2);
216 max_uid
= init_label_info (f
) + 1;
218 /* If we are performing cross jump optimizations, then initialize
219 tables mapping UIDs to EH regions to avoid incorrect movement
220 of insns from one EH region to another. */
221 if (flag_exceptions
&& cross_jump
)
222 init_insn_eh_region (f
, max_uid
);
224 if (! mark_labels_only
)
225 delete_barrier_successors (f
);
227 /* Leave some extra room for labels and duplicate exit test insns
229 max_jump_chain
= max_uid
* 14 / 10;
230 jump_chain
= (rtx
*) xcalloc (max_jump_chain
, sizeof (rtx
));
232 mark_all_labels (f
, cross_jump
);
234 /* Keep track of labels used from static data;
235 they cannot ever be deleted. */
237 for (insn
= forced_labels
; insn
; insn
= XEXP (insn
, 1))
238 LABEL_NUSES (XEXP (insn
, 0))++;
240 check_exception_handler_labels ();
242 /* Keep track of labels used for marking handlers for exception
243 regions; they cannot usually be deleted. */
245 for (insn
= exception_handler_labels
; insn
; insn
= XEXP (insn
, 1))
246 LABEL_NUSES (XEXP (insn
, 0))++;
248 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
249 notes and recompute LABEL_NUSES. */
250 if (mark_labels_only
)
254 exception_optimize ();
256 last_insn
= delete_unreferenced_labels (f
);
259 delete_noop_moves (f
);
261 /* If we haven't yet gotten to reload and we have just run regscan,
262 delete any insn that sets a register that isn't used elsewhere.
263 This helps some of the optimizations below by having less insns
264 being jumped around. */
266 if (optimize
&& ! reload_completed
&& after_regscan
)
267 for (insn
= f
; insn
; insn
= next
)
269 rtx set
= single_set (insn
);
271 next
= NEXT_INSN (insn
);
273 if (set
&& GET_CODE (SET_DEST (set
)) == REG
274 && REGNO (SET_DEST (set
)) >= FIRST_PSEUDO_REGISTER
275 && REGNO_FIRST_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
276 /* We use regno_last_note_uid so as not to delete the setting
277 of a reg that's used in notes. A subsequent optimization
278 might arrange to use that reg for real. */
279 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
280 && ! side_effects_p (SET_SRC (set
))
281 && ! find_reg_note (insn
, REG_RETVAL
, 0)
282 /* An ADDRESSOF expression can turn into a use of the internal arg
283 pointer, so do not delete the initialization of the internal
284 arg pointer yet. If it is truly dead, flow will delete the
285 initializing insn. */
286 && SET_DEST (set
) != current_function_internal_arg_pointer
)
290 /* Now iterate optimizing jumps until nothing changes over one pass. */
292 old_max_reg
= max_reg_num ();
297 for (insn
= f
; insn
; insn
= next
)
300 rtx temp
, temp1
, temp2
= NULL_RTX
;
301 rtx temp4 ATTRIBUTE_UNUSED
;
303 int this_is_simplejump
, this_is_condjump
;
304 int this_is_condjump_in_parallel
;
306 next
= NEXT_INSN (insn
);
308 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
309 jump. Try to optimize by duplicating the loop exit test if so.
310 This is only safe immediately after regscan, because it uses
311 the values of regno_first_uid and regno_last_uid. */
312 if (after_regscan
&& GET_CODE (insn
) == NOTE
313 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
314 && (temp1
= next_nonnote_insn (insn
)) != 0
315 && simplejump_p (temp1
))
317 temp
= PREV_INSN (insn
);
318 if (duplicate_loop_exit_test (insn
))
321 next
= NEXT_INSN (temp
);
326 if (GET_CODE (insn
) != JUMP_INSN
)
329 this_is_simplejump
= simplejump_p (insn
);
330 this_is_condjump
= condjump_p (insn
);
331 this_is_condjump_in_parallel
= condjump_in_parallel_p (insn
);
333 /* Tension the labels in dispatch tables. */
335 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
)
336 changed
|= tension_vector_labels (PATTERN (insn
), 0);
337 if (GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
338 changed
|= tension_vector_labels (PATTERN (insn
), 1);
340 /* See if this jump goes to another jump and redirect if so. */
341 nlabel
= follow_jumps (JUMP_LABEL (insn
));
342 if (nlabel
!= JUMP_LABEL (insn
))
343 changed
|= redirect_jump (insn
, nlabel
);
345 if (! optimize
|| minimal
)
348 /* If a dispatch table always goes to the same place,
349 get rid of it and replace the insn that uses it. */
351 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
352 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
355 rtx pat
= PATTERN (insn
);
356 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
357 int len
= XVECLEN (pat
, diff_vec_p
);
358 rtx dispatch
= prev_real_insn (insn
);
361 for (i
= 0; i
< len
; i
++)
362 if (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)
363 != XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0))
368 && GET_CODE (dispatch
) == JUMP_INSN
369 && JUMP_LABEL (dispatch
) != 0
370 /* Don't mess with a casesi insn.
371 XXX according to the comment before computed_jump_p(),
372 all casesi insns should be a parallel of the jump
373 and a USE of a LABEL_REF. */
374 && ! ((set
= single_set (dispatch
)) != NULL
375 && (GET_CODE (SET_SRC (set
)) == IF_THEN_ELSE
))
376 && next_real_insn (JUMP_LABEL (dispatch
)) == insn
)
378 redirect_tablejump (dispatch
,
379 XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0));
384 /* If a jump references the end of the function, try to turn
385 it into a RETURN insn, possibly a conditional one. */
386 if (JUMP_LABEL (insn
) != 0
387 && (next_active_insn (JUMP_LABEL (insn
)) == 0
388 || GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn
))))
390 changed
|= redirect_jump (insn
, NULL_RTX
);
392 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
394 /* Detect jump to following insn. */
395 if (reallabelprev
== insn
&& this_is_condjump
)
397 next
= next_real_insn (JUMP_LABEL (insn
));
403 /* Detect a conditional jump going to the same place
404 as an immediately following unconditional jump. */
405 else if (this_is_condjump
406 && (temp
= next_active_insn (insn
)) != 0
407 && simplejump_p (temp
)
408 && (next_active_insn (JUMP_LABEL (insn
))
409 == next_active_insn (JUMP_LABEL (temp
))))
411 /* Don't mess up test coverage analysis. */
413 if (flag_test_coverage
&& !reload_completed
)
414 for (temp2
= insn
; temp2
!= temp
; temp2
= NEXT_INSN (temp2
))
415 if (GET_CODE (temp2
) == NOTE
&& NOTE_LINE_NUMBER (temp2
) > 0)
426 /* Detect a conditional jump jumping over an unconditional jump. */
428 else if ((this_is_condjump
|| this_is_condjump_in_parallel
)
429 && ! this_is_simplejump
430 && reallabelprev
!= 0
431 && GET_CODE (reallabelprev
) == JUMP_INSN
432 && prev_active_insn (reallabelprev
) == insn
433 && no_labels_between_p (insn
, reallabelprev
)
434 && simplejump_p (reallabelprev
))
436 /* When we invert the unconditional jump, we will be
437 decrementing the usage count of its old label.
438 Make sure that we don't delete it now because that
439 might cause the following code to be deleted. */
440 rtx prev_uses
= prev_nonnote_insn (reallabelprev
);
441 rtx prev_label
= JUMP_LABEL (insn
);
444 ++LABEL_NUSES (prev_label
);
446 if (invert_jump (insn
, JUMP_LABEL (reallabelprev
)))
448 /* It is very likely that if there are USE insns before
449 this jump, they hold REG_DEAD notes. These REG_DEAD
450 notes are no longer valid due to this optimization,
451 and will cause the life-analysis that following passes
452 (notably delayed-branch scheduling) to think that
453 these registers are dead when they are not.
455 To prevent this trouble, we just remove the USE insns
456 from the insn chain. */
458 while (prev_uses
&& GET_CODE (prev_uses
) == INSN
459 && GET_CODE (PATTERN (prev_uses
)) == USE
)
461 rtx useless
= prev_uses
;
462 prev_uses
= prev_nonnote_insn (prev_uses
);
463 delete_insn (useless
);
466 delete_insn (reallabelprev
);
470 /* We can now safely delete the label if it is unreferenced
471 since the delete_insn above has deleted the BARRIER. */
472 if (prev_label
&& --LABEL_NUSES (prev_label
) == 0)
473 delete_insn (prev_label
);
475 next
= NEXT_INSN (insn
);
478 /* If we have an unconditional jump preceded by a USE, try to put
479 the USE before the target and jump there. This simplifies many
480 of the optimizations below since we don't have to worry about
481 dealing with these USE insns. We only do this if the label
482 being branch to already has the identical USE or if code
483 never falls through to that label. */
485 else if (this_is_simplejump
486 && (temp
= prev_nonnote_insn (insn
)) != 0
487 && GET_CODE (temp
) == INSN
488 && GET_CODE (PATTERN (temp
)) == USE
489 && (temp1
= prev_nonnote_insn (JUMP_LABEL (insn
))) != 0
490 && (GET_CODE (temp1
) == BARRIER
491 || (GET_CODE (temp1
) == INSN
492 && rtx_equal_p (PATTERN (temp
), PATTERN (temp1
))))
493 /* Don't do this optimization if we have a loop containing
494 only the USE instruction, and the loop start label has
495 a usage count of 1. This is because we will redo this
496 optimization everytime through the outer loop, and jump
497 opt will never exit. */
498 && ! ((temp2
= prev_nonnote_insn (temp
)) != 0
499 && temp2
== JUMP_LABEL (insn
)
500 && LABEL_NUSES (temp2
) == 1))
502 if (GET_CODE (temp1
) == BARRIER
)
504 emit_insn_after (PATTERN (temp
), temp1
);
505 temp1
= NEXT_INSN (temp1
);
509 redirect_jump (insn
, get_label_before (temp1
));
510 reallabelprev
= prev_real_insn (temp1
);
512 next
= NEXT_INSN (insn
);
516 /* Detect a conditional jump jumping over an unconditional trap. */
518 && this_is_condjump
&& ! this_is_simplejump
519 && reallabelprev
!= 0
520 && GET_CODE (reallabelprev
) == INSN
521 && GET_CODE (PATTERN (reallabelprev
)) == TRAP_IF
522 && TRAP_CONDITION (PATTERN (reallabelprev
)) == const_true_rtx
523 && prev_active_insn (reallabelprev
) == insn
524 && no_labels_between_p (insn
, reallabelprev
)
525 && (temp2
= get_condition (insn
, &temp4
))
526 && can_reverse_comparison_p (temp2
, insn
))
528 rtx
new = gen_cond_trap (reverse_condition (GET_CODE (temp2
)),
529 XEXP (temp2
, 0), XEXP (temp2
, 1),
530 TRAP_CODE (PATTERN (reallabelprev
)));
534 emit_insn_before (new, temp4
);
535 delete_insn (reallabelprev
);
541 /* Detect a jump jumping to an unconditional trap. */
542 else if (HAVE_trap
&& this_is_condjump
543 && (temp
= next_active_insn (JUMP_LABEL (insn
)))
544 && GET_CODE (temp
) == INSN
545 && GET_CODE (PATTERN (temp
)) == TRAP_IF
546 && (this_is_simplejump
547 || (temp2
= get_condition (insn
, &temp4
))))
549 rtx tc
= TRAP_CONDITION (PATTERN (temp
));
551 if (tc
== const_true_rtx
552 || (! this_is_simplejump
&& rtx_equal_p (temp2
, tc
)))
555 /* Replace an unconditional jump to a trap with a trap. */
556 if (this_is_simplejump
)
558 emit_barrier_after (emit_insn_before (gen_trap (), insn
));
563 new = gen_cond_trap (GET_CODE (temp2
), XEXP (temp2
, 0),
565 TRAP_CODE (PATTERN (temp
)));
568 emit_insn_before (new, temp4
);
574 /* If the trap condition and jump condition are mutually
575 exclusive, redirect the jump to the following insn. */
576 else if (GET_RTX_CLASS (GET_CODE (tc
)) == '<'
577 && ! this_is_simplejump
578 && swap_condition (GET_CODE (temp2
)) == GET_CODE (tc
)
579 && rtx_equal_p (XEXP (tc
, 0), XEXP (temp2
, 0))
580 && rtx_equal_p (XEXP (tc
, 1), XEXP (temp2
, 1))
581 && redirect_jump (insn
, get_label_after (temp
)))
590 /* Now that the jump has been tensioned,
591 try cross jumping: check for identical code
592 before the jump and before its target label. */
594 /* First, cross jumping of conditional jumps: */
596 if (cross_jump
&& condjump_p (insn
))
598 rtx newjpos
, newlpos
;
599 rtx x
= prev_real_insn (JUMP_LABEL (insn
));
601 /* A conditional jump may be crossjumped
602 only if the place it jumps to follows
603 an opposing jump that comes back here. */
605 if (x
!= 0 && ! jump_back_p (x
, insn
))
606 /* We have no opposing jump;
607 cannot cross jump this insn. */
611 /* TARGET is nonzero if it is ok to cross jump
612 to code before TARGET. If so, see if matches. */
614 find_cross_jump (insn
, x
, 2,
619 do_cross_jump (insn
, newjpos
, newlpos
);
620 /* Make the old conditional jump
621 into an unconditional one. */
622 SET_SRC (PATTERN (insn
))
623 = gen_rtx_LABEL_REF (VOIDmode
, JUMP_LABEL (insn
));
624 INSN_CODE (insn
) = -1;
625 emit_barrier_after (insn
);
626 /* Add to jump_chain unless this is a new label
627 whose UID is too large. */
628 if (INSN_UID (JUMP_LABEL (insn
)) < max_jump_chain
)
630 jump_chain
[INSN_UID (insn
)]
631 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
632 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
639 /* Cross jumping of unconditional jumps:
640 a few differences. */
642 if (cross_jump
&& simplejump_p (insn
))
644 rtx newjpos
, newlpos
;
649 /* TARGET is nonzero if it is ok to cross jump
650 to code before TARGET. If so, see if matches. */
651 find_cross_jump (insn
, JUMP_LABEL (insn
), 1,
654 /* If cannot cross jump to code before the label,
655 see if we can cross jump to another jump to
657 /* Try each other jump to this label. */
658 if (INSN_UID (JUMP_LABEL (insn
)) < max_uid
)
659 for (target
= jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
660 target
!= 0 && newjpos
== 0;
661 target
= jump_chain
[INSN_UID (target
)])
663 && JUMP_LABEL (target
) == JUMP_LABEL (insn
)
664 /* Ignore TARGET if it's deleted. */
665 && ! INSN_DELETED_P (target
))
666 find_cross_jump (insn
, target
, 2,
671 do_cross_jump (insn
, newjpos
, newlpos
);
677 /* This code was dead in the previous jump.c! */
678 if (cross_jump
&& GET_CODE (PATTERN (insn
)) == RETURN
)
680 /* Return insns all "jump to the same place"
681 so we can cross-jump between any two of them. */
683 rtx newjpos
, newlpos
, target
;
687 /* If cannot cross jump to code before the label,
688 see if we can cross jump to another jump to
690 /* Try each other jump to this label. */
691 for (target
= jump_chain
[0];
692 target
!= 0 && newjpos
== 0;
693 target
= jump_chain
[INSN_UID (target
)])
695 && ! INSN_DELETED_P (target
)
696 && GET_CODE (PATTERN (target
)) == RETURN
)
697 find_cross_jump (insn
, target
, 2,
702 do_cross_jump (insn
, newjpos
, newlpos
);
713 /* Delete extraneous line number notes.
714 Note that two consecutive notes for different lines are not really
715 extraneous. There should be some indication where that line belonged,
716 even if it became empty. */
721 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
722 if (GET_CODE (insn
) == NOTE
&& NOTE_LINE_NUMBER (insn
) >= 0)
724 /* Delete this note if it is identical to previous note. */
726 && NOTE_SOURCE_FILE (insn
) == NOTE_SOURCE_FILE (last_note
)
727 && NOTE_LINE_NUMBER (insn
) == NOTE_LINE_NUMBER (last_note
))
737 /* CAN_REACH_END is persistent for each function. Once set it should
738 not be cleared. This is especially true for the case where we
739 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
740 the front-end before compiling each function. */
741 if (! minimal
&& calculate_can_reach_end (last_insn
, optimize
!= 0))
750 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
751 notes whose labels don't occur in the insn any more. Returns the
752 largest INSN_UID found. */
760 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
762 if (GET_CODE (insn
) == CODE_LABEL
)
763 LABEL_NUSES (insn
) = (LABEL_PRESERVE_P (insn
) != 0);
764 else if (GET_CODE (insn
) == JUMP_INSN
)
765 JUMP_LABEL (insn
) = 0;
766 else if (GET_CODE (insn
) == INSN
|| GET_CODE (insn
) == CALL_INSN
)
770 for (note
= REG_NOTES (insn
); note
; note
= next
)
772 next
= XEXP (note
, 1);
773 if (REG_NOTE_KIND (note
) == REG_LABEL
774 && ! reg_mentioned_p (XEXP (note
, 0), PATTERN (insn
)))
775 remove_note (insn
, note
);
778 if (INSN_UID (insn
) > largest_uid
)
779 largest_uid
= INSN_UID (insn
);
785 /* Delete insns following barriers, up to next label.
787 Also delete no-op jumps created by gcse. */
790 delete_barrier_successors (f
)
795 for (insn
= f
; insn
;)
797 if (GET_CODE (insn
) == BARRIER
)
799 insn
= NEXT_INSN (insn
);
801 never_reached_warning (insn
);
803 while (insn
!= 0 && GET_CODE (insn
) != CODE_LABEL
)
805 if (GET_CODE (insn
) == NOTE
806 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)
807 insn
= NEXT_INSN (insn
);
809 insn
= delete_insn (insn
);
811 /* INSN is now the code_label. */
814 /* Also remove (set (pc) (pc)) insns which can be created by
815 gcse. We eliminate such insns now to avoid having them
816 cause problems later. */
817 else if (GET_CODE (insn
) == JUMP_INSN
818 && GET_CODE (PATTERN (insn
)) == SET
819 && SET_SRC (PATTERN (insn
)) == pc_rtx
820 && SET_DEST (PATTERN (insn
)) == pc_rtx
)
821 insn
= delete_insn (insn
);
824 insn
= NEXT_INSN (insn
);
828 /* Mark the label each jump jumps to.
829 Combine consecutive labels, and count uses of labels.
831 For each label, make a chain (using `jump_chain')
832 of all the *unconditional* jumps that jump to it;
833 also make a chain of all returns.
835 CROSS_JUMP indicates whether we are doing cross jumping
836 and if we are whether we will be paying attention to
837 death notes or not. */
840 mark_all_labels (f
, cross_jump
)
846 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
847 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
849 if (GET_CODE (insn
) == CALL_INSN
850 && GET_CODE (PATTERN (insn
)) == CALL_PLACEHOLDER
)
852 mark_all_labels (XEXP (PATTERN (insn
), 0), cross_jump
);
853 mark_all_labels (XEXP (PATTERN (insn
), 1), cross_jump
);
854 mark_all_labels (XEXP (PATTERN (insn
), 2), cross_jump
);
858 mark_jump_label (PATTERN (insn
), insn
, cross_jump
, 0);
859 if (! INSN_DELETED_P (insn
) && GET_CODE (insn
) == JUMP_INSN
)
861 if (JUMP_LABEL (insn
) != 0 && simplejump_p (insn
))
863 jump_chain
[INSN_UID (insn
)]
864 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
865 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
867 if (GET_CODE (PATTERN (insn
)) == RETURN
)
869 jump_chain
[INSN_UID (insn
)] = jump_chain
[0];
870 jump_chain
[0] = insn
;
876 /* Delete all labels already not referenced.
877 Also find and return the last insn. */
880 delete_unreferenced_labels (f
)
883 rtx final
= NULL_RTX
;
886 for (insn
= f
; insn
; )
888 if (GET_CODE (insn
) == CODE_LABEL
889 && LABEL_NUSES (insn
) == 0
890 && LABEL_ALTERNATE_NAME (insn
) == NULL
)
891 insn
= delete_insn (insn
);
895 insn
= NEXT_INSN (insn
);
902 /* Delete various simple forms of moves which have no necessary
906 delete_noop_moves (f
)
911 for (insn
= f
; insn
; )
913 next
= NEXT_INSN (insn
);
915 if (GET_CODE (insn
) == INSN
)
917 register rtx body
= PATTERN (insn
);
919 /* Detect and delete no-op move instructions
920 resulting from not allocating a parameter in a register. */
922 if (GET_CODE (body
) == SET
923 && (SET_DEST (body
) == SET_SRC (body
)
924 || (GET_CODE (SET_DEST (body
)) == MEM
925 && GET_CODE (SET_SRC (body
)) == MEM
926 && rtx_equal_p (SET_SRC (body
), SET_DEST (body
))))
927 && ! (GET_CODE (SET_DEST (body
)) == MEM
928 && MEM_VOLATILE_P (SET_DEST (body
)))
929 && ! (GET_CODE (SET_SRC (body
)) == MEM
930 && MEM_VOLATILE_P (SET_SRC (body
))))
931 delete_computation (insn
);
933 /* Detect and ignore no-op move instructions
934 resulting from smart or fortuitous register allocation. */
936 else if (GET_CODE (body
) == SET
)
938 int sreg
= true_regnum (SET_SRC (body
));
939 int dreg
= true_regnum (SET_DEST (body
));
941 if (sreg
== dreg
&& sreg
>= 0)
943 else if (sreg
>= 0 && dreg
>= 0)
946 rtx tem
= find_equiv_reg (NULL_RTX
, insn
, 0,
947 sreg
, NULL_PTR
, dreg
,
948 GET_MODE (SET_SRC (body
)));
951 && GET_MODE (tem
) == GET_MODE (SET_DEST (body
)))
953 /* DREG may have been the target of a REG_DEAD note in
954 the insn which makes INSN redundant. If so, reorg
955 would still think it is dead. So search for such a
956 note and delete it if we find it. */
957 if (! find_regno_note (insn
, REG_UNUSED
, dreg
))
958 for (trial
= prev_nonnote_insn (insn
);
959 trial
&& GET_CODE (trial
) != CODE_LABEL
;
960 trial
= prev_nonnote_insn (trial
))
961 if (find_regno_note (trial
, REG_DEAD
, dreg
))
963 remove_death (dreg
, trial
);
967 /* Deleting insn could lose a death-note for SREG. */
968 if ((trial
= find_regno_note (insn
, REG_DEAD
, sreg
)))
970 /* Change this into a USE so that we won't emit
971 code for it, but still can keep the note. */
973 = gen_rtx_USE (VOIDmode
, XEXP (trial
, 0));
974 INSN_CODE (insn
) = -1;
975 /* Remove all reg notes but the REG_DEAD one. */
976 REG_NOTES (insn
) = trial
;
977 XEXP (trial
, 1) = NULL_RTX
;
983 else if (dreg
>= 0 && CONSTANT_P (SET_SRC (body
))
984 && find_equiv_reg (SET_SRC (body
), insn
, 0, dreg
,
986 GET_MODE (SET_DEST (body
))))
988 /* This handles the case where we have two consecutive
989 assignments of the same constant to pseudos that didn't
990 get a hard reg. Each SET from the constant will be
991 converted into a SET of the spill register and an
992 output reload will be made following it. This produces
993 two loads of the same constant into the same spill
998 /* Look back for a death note for the first reg.
999 If there is one, it is no longer accurate. */
1000 while (in_insn
&& GET_CODE (in_insn
) != CODE_LABEL
)
1002 if ((GET_CODE (in_insn
) == INSN
1003 || GET_CODE (in_insn
) == JUMP_INSN
)
1004 && find_regno_note (in_insn
, REG_DEAD
, dreg
))
1006 remove_death (dreg
, in_insn
);
1009 in_insn
= PREV_INSN (in_insn
);
1012 /* Delete the second load of the value. */
1016 else if (GET_CODE (body
) == PARALLEL
)
1018 /* If each part is a set between two identical registers or
1019 a USE or CLOBBER, delete the insn. */
1023 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; i
--)
1025 tem
= XVECEXP (body
, 0, i
);
1026 if (GET_CODE (tem
) == USE
|| GET_CODE (tem
) == CLOBBER
)
1029 if (GET_CODE (tem
) != SET
1030 || (sreg
= true_regnum (SET_SRC (tem
))) < 0
1031 || (dreg
= true_regnum (SET_DEST (tem
))) < 0
1039 /* Also delete insns to store bit fields if they are no-ops. */
1040 /* Not worth the hair to detect this in the big-endian case. */
1041 else if (! BYTES_BIG_ENDIAN
1042 && GET_CODE (body
) == SET
1043 && GET_CODE (SET_DEST (body
)) == ZERO_EXTRACT
1044 && XEXP (SET_DEST (body
), 2) == const0_rtx
1045 && XEXP (SET_DEST (body
), 0) == SET_SRC (body
)
1046 && ! (GET_CODE (SET_SRC (body
)) == MEM
1047 && MEM_VOLATILE_P (SET_SRC (body
))))
1054 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
1055 If so indicate that this function can drop off the end by returning
1058 CHECK_DELETED indicates whether we must check if the note being
1059 searched for has the deleted flag set.
1061 DELETE_FINAL_NOTE indicates whether we should delete the note
1065 calculate_can_reach_end (last
, delete_final_note
)
1067 int delete_final_note
;
1072 while (insn
!= NULL_RTX
)
1076 /* One label can follow the end-note: the return label. */
1077 if (GET_CODE (insn
) == CODE_LABEL
&& n_labels
-- > 0)
1079 /* Ordinary insns can follow it if returning a structure. */
1080 else if (GET_CODE (insn
) == INSN
)
1082 /* If machine uses explicit RETURN insns, no epilogue,
1083 then one of them follows the note. */
1084 else if (GET_CODE (insn
) == JUMP_INSN
1085 && GET_CODE (PATTERN (insn
)) == RETURN
)
1087 /* A barrier can follow the return insn. */
1088 else if (GET_CODE (insn
) == BARRIER
)
1090 /* Other kinds of notes can follow also. */
1091 else if (GET_CODE (insn
) == NOTE
1092 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)
1098 insn
= PREV_INSN (insn
);
1101 /* See if we backed up to the appropriate type of note. */
1102 if (insn
!= NULL_RTX
1103 && GET_CODE (insn
) == NOTE
1104 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_FUNCTION_END
)
1106 if (delete_final_note
)
1114 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
1115 jump. Assume that this unconditional jump is to the exit test code. If
1116 the code is sufficiently simple, make a copy of it before INSN,
1117 followed by a jump to the exit of the loop. Then delete the unconditional
1120 Return 1 if we made the change, else 0.
1122 This is only safe immediately after a regscan pass because it uses the
1123 values of regno_first_uid and regno_last_uid. */
1126 duplicate_loop_exit_test (loop_start
)
1129 rtx insn
, set
, reg
, p
, link
;
1130 rtx copy
= 0, first_copy
= 0;
1132 rtx exitcode
= NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start
)));
1134 int max_reg
= max_reg_num ();
1137 /* Scan the exit code. We do not perform this optimization if any insn:
1141 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
1142 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
1143 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
1146 We also do not do this if we find an insn with ASM_OPERANDS. While
1147 this restriction should not be necessary, copying an insn with
1148 ASM_OPERANDS can confuse asm_noperands in some cases.
1150 Also, don't do this if the exit code is more than 20 insns. */
1152 for (insn
= exitcode
;
1154 && ! (GET_CODE (insn
) == NOTE
1155 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
);
1156 insn
= NEXT_INSN (insn
))
1158 switch (GET_CODE (insn
))
1164 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
1165 a jump immediately after the loop start that branches outside
1166 the loop but within an outer loop, near the exit test.
1167 If we copied this exit test and created a phony
1168 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
1169 before the exit test look like these could be safely moved
1170 out of the loop even if they actually may be never executed.
1171 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
1173 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
1174 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
)
1178 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
1179 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
))
1180 /* If we were to duplicate this code, we would not move
1181 the BLOCK notes, and so debugging the moved code would
1182 be difficult. Thus, we only move the code with -O2 or
1189 /* The code below would grossly mishandle REG_WAS_0 notes,
1190 so get rid of them here. */
1191 while ((p
= find_reg_note (insn
, REG_WAS_0
, NULL_RTX
)) != 0)
1192 remove_note (insn
, p
);
1193 if (++num_insns
> 20
1194 || find_reg_note (insn
, REG_RETVAL
, NULL_RTX
)
1195 || find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
1203 /* Unless INSN is zero, we can do the optimization. */
1209 /* See if any insn sets a register only used in the loop exit code and
1210 not a user variable. If so, replace it with a new register. */
1211 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
1212 if (GET_CODE (insn
) == INSN
1213 && (set
= single_set (insn
)) != 0
1214 && ((reg
= SET_DEST (set
), GET_CODE (reg
) == REG
)
1215 || (GET_CODE (reg
) == SUBREG
1216 && (reg
= SUBREG_REG (reg
), GET_CODE (reg
) == REG
)))
1217 && REGNO (reg
) >= FIRST_PSEUDO_REGISTER
1218 && REGNO_FIRST_UID (REGNO (reg
)) == INSN_UID (insn
))
1220 for (p
= NEXT_INSN (insn
); p
!= lastexit
; p
= NEXT_INSN (p
))
1221 if (REGNO_LAST_UID (REGNO (reg
)) == INSN_UID (p
))
1226 /* We can do the replacement. Allocate reg_map if this is the
1227 first replacement we found. */
1229 reg_map
= (rtx
*) xcalloc (max_reg
, sizeof (rtx
));
1231 REG_LOOP_TEST_P (reg
) = 1;
1233 reg_map
[REGNO (reg
)] = gen_reg_rtx (GET_MODE (reg
));
1237 /* Now copy each insn. */
1238 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
1240 switch (GET_CODE (insn
))
1243 copy
= emit_barrier_before (loop_start
);
1246 /* Only copy line-number notes. */
1247 if (NOTE_LINE_NUMBER (insn
) >= 0)
1249 copy
= emit_note_before (NOTE_LINE_NUMBER (insn
), loop_start
);
1250 NOTE_SOURCE_FILE (copy
) = NOTE_SOURCE_FILE (insn
);
1255 copy
= emit_insn_before (copy_insn (PATTERN (insn
)), loop_start
);
1257 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
1259 mark_jump_label (PATTERN (copy
), copy
, 0, 0);
1261 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
1263 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
1264 if (REG_NOTE_KIND (link
) != REG_LABEL
)
1266 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link
),
1269 if (reg_map
&& REG_NOTES (copy
))
1270 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
1274 copy
= emit_jump_insn_before (copy_insn (PATTERN (insn
)), loop_start
);
1276 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
1277 mark_jump_label (PATTERN (copy
), copy
, 0, 0);
1278 if (REG_NOTES (insn
))
1280 REG_NOTES (copy
) = copy_insn_1 (REG_NOTES (insn
));
1282 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
1285 /* If this is a simple jump, add it to the jump chain. */
1287 if (INSN_UID (copy
) < max_jump_chain
&& JUMP_LABEL (copy
)
1288 && simplejump_p (copy
))
1290 jump_chain
[INSN_UID (copy
)]
1291 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
1292 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
1300 /* Record the first insn we copied. We need it so that we can
1301 scan the copied insns for new pseudo registers. */
1306 /* Now clean up by emitting a jump to the end label and deleting the jump
1307 at the start of the loop. */
1308 if (! copy
|| GET_CODE (copy
) != BARRIER
)
1310 copy
= emit_jump_insn_before (gen_jump (get_label_after (insn
)),
1313 /* Record the first insn we copied. We need it so that we can
1314 scan the copied insns for new pseudo registers. This may not
1315 be strictly necessary since we should have copied at least one
1316 insn above. But I am going to be safe. */
1320 mark_jump_label (PATTERN (copy
), copy
, 0, 0);
1321 if (INSN_UID (copy
) < max_jump_chain
1322 && INSN_UID (JUMP_LABEL (copy
)) < max_jump_chain
)
1324 jump_chain
[INSN_UID (copy
)]
1325 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
1326 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
1328 emit_barrier_before (loop_start
);
1331 /* Now scan from the first insn we copied to the last insn we copied
1332 (copy) for new pseudo registers. Do this after the code to jump to
1333 the end label since that might create a new pseudo too. */
1334 reg_scan_update (first_copy
, copy
, max_reg
);
1336 /* Mark the exit code as the virtual top of the converted loop. */
1337 emit_note_before (NOTE_INSN_LOOP_VTOP
, exitcode
);
1339 delete_insn (next_nonnote_insn (loop_start
));
1348 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
1349 loop-end notes between START and END out before START. Assume that
1350 END is not such a note. START may be such a note. Returns the value
1351 of the new starting insn, which may be different if the original start
1355 squeeze_notes (start
, end
)
1361 for (insn
= start
; insn
!= end
; insn
= next
)
1363 next
= NEXT_INSN (insn
);
1364 if (GET_CODE (insn
) == NOTE
1365 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
1366 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
1367 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
1368 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
1369 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
1370 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_VTOP
))
1376 rtx prev
= PREV_INSN (insn
);
1377 PREV_INSN (insn
) = PREV_INSN (start
);
1378 NEXT_INSN (insn
) = start
;
1379 NEXT_INSN (PREV_INSN (insn
)) = insn
;
1380 PREV_INSN (NEXT_INSN (insn
)) = insn
;
1381 NEXT_INSN (prev
) = next
;
1382 PREV_INSN (next
) = prev
;
1390 /* Compare the instructions before insn E1 with those before E2
1391 to find an opportunity for cross jumping.
1392 (This means detecting identical sequences of insns followed by
1393 jumps to the same place, or followed by a label and a jump
1394 to that label, and replacing one with a jump to the other.)
1396 Assume E1 is a jump that jumps to label E2
1397 (that is not always true but it might as well be).
1398 Find the longest possible equivalent sequences
1399 and store the first insns of those sequences into *F1 and *F2.
1400 Store zero there if no equivalent preceding instructions are found.
1402 We give up if we find a label in stream 1.
1403 Actually we could transfer that label into stream 2. */
1406 find_cross_jump (e1
, e2
, minimum
, f1
, f2
)
1411 register rtx i1
= e1
, i2
= e2
;
1412 register rtx p1
, p2
;
1415 rtx last1
= 0, last2
= 0;
1416 rtx afterlast1
= 0, afterlast2
= 0;
1423 i1
= prev_nonnote_insn (i1
);
1425 i2
= PREV_INSN (i2
);
1426 while (i2
&& (GET_CODE (i2
) == NOTE
|| GET_CODE (i2
) == CODE_LABEL
))
1427 i2
= PREV_INSN (i2
);
1432 /* Don't allow the range of insns preceding E1 or E2
1433 to include the other (E2 or E1). */
1434 if (i2
== e1
|| i1
== e2
)
1437 /* If we will get to this code by jumping, those jumps will be
1438 tensioned to go directly to the new label (before I2),
1439 so this cross-jumping won't cost extra. So reduce the minimum. */
1440 if (GET_CODE (i1
) == CODE_LABEL
)
1446 if (i2
== 0 || GET_CODE (i1
) != GET_CODE (i2
))
1449 /* Avoid moving insns across EH regions if either of the insns
1452 && (asynchronous_exceptions
|| GET_CODE (i1
) == CALL_INSN
)
1453 && !in_same_eh_region (i1
, i2
))
1459 /* If this is a CALL_INSN, compare register usage information.
1460 If we don't check this on stack register machines, the two
1461 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1462 numbers of stack registers in the same basic block.
1463 If we don't check this on machines with delay slots, a delay slot may
1464 be filled that clobbers a parameter expected by the subroutine.
1466 ??? We take the simple route for now and assume that if they're
1467 equal, they were constructed identically. */
1469 if (GET_CODE (i1
) == CALL_INSN
1470 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1
),
1471 CALL_INSN_FUNCTION_USAGE (i2
)))
1475 /* If cross_jump_death_matters is not 0, the insn's mode
1476 indicates whether or not the insn contains any stack-like
1479 if (!lose
&& cross_jump_death_matters
&& stack_regs_mentioned (i1
))
1481 /* If register stack conversion has already been done, then
1482 death notes must also be compared before it is certain that
1483 the two instruction streams match. */
1486 HARD_REG_SET i1_regset
, i2_regset
;
1488 CLEAR_HARD_REG_SET (i1_regset
);
1489 CLEAR_HARD_REG_SET (i2_regset
);
1491 for (note
= REG_NOTES (i1
); note
; note
= XEXP (note
, 1))
1492 if (REG_NOTE_KIND (note
) == REG_DEAD
1493 && STACK_REG_P (XEXP (note
, 0)))
1494 SET_HARD_REG_BIT (i1_regset
, REGNO (XEXP (note
, 0)));
1496 for (note
= REG_NOTES (i2
); 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 (i2_regset
, REGNO (XEXP (note
, 0)));
1501 GO_IF_HARD_REG_EQUAL (i1_regset
, i2_regset
, done
);
1510 /* Don't allow old-style asm or volatile extended asms to be accepted
1511 for cross jumping purposes. It is conceptually correct to allow
1512 them, since cross-jumping preserves the dynamic instruction order
1513 even though it is changing the static instruction order. However,
1514 if an asm is being used to emit an assembler pseudo-op, such as
1515 the MIPS `.set reorder' pseudo-op, then the static instruction order
1516 matters and it must be preserved. */
1517 if (GET_CODE (p1
) == ASM_INPUT
|| GET_CODE (p2
) == ASM_INPUT
1518 || (GET_CODE (p1
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p1
))
1519 || (GET_CODE (p2
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p2
)))
1522 if (lose
|| GET_CODE (p1
) != GET_CODE (p2
)
1523 || ! rtx_renumbered_equal_p (p1
, p2
))
1525 /* The following code helps take care of G++ cleanups. */
1529 if (!lose
&& GET_CODE (p1
) == GET_CODE (p2
)
1530 && ((equiv1
= find_reg_note (i1
, REG_EQUAL
, NULL_RTX
)) != 0
1531 || (equiv1
= find_reg_note (i1
, REG_EQUIV
, NULL_RTX
)) != 0)
1532 && ((equiv2
= find_reg_note (i2
, REG_EQUAL
, NULL_RTX
)) != 0
1533 || (equiv2
= find_reg_note (i2
, REG_EQUIV
, NULL_RTX
)) != 0)
1534 /* If the equivalences are not to a constant, they may
1535 reference pseudos that no longer exist, so we can't
1537 && CONSTANT_P (XEXP (equiv1
, 0))
1538 && rtx_equal_p (XEXP (equiv1
, 0), XEXP (equiv2
, 0)))
1540 rtx s1
= single_set (i1
);
1541 rtx s2
= single_set (i2
);
1542 if (s1
!= 0 && s2
!= 0
1543 && rtx_renumbered_equal_p (SET_DEST (s1
), SET_DEST (s2
)))
1545 validate_change (i1
, &SET_SRC (s1
), XEXP (equiv1
, 0), 1);
1546 validate_change (i2
, &SET_SRC (s2
), XEXP (equiv2
, 0), 1);
1547 if (! rtx_renumbered_equal_p (p1
, p2
))
1549 else if (apply_change_group ())
1554 /* Insns fail to match; cross jumping is limited to the following
1558 /* Don't allow the insn after a compare to be shared by
1559 cross-jumping unless the compare is also shared.
1560 Here, if either of these non-matching insns is a compare,
1561 exclude the following insn from possible cross-jumping. */
1562 if (sets_cc0_p (p1
) || sets_cc0_p (p2
))
1563 last1
= afterlast1
, last2
= afterlast2
, ++minimum
;
1566 /* If cross-jumping here will feed a jump-around-jump
1567 optimization, this jump won't cost extra, so reduce
1569 if (GET_CODE (i1
) == JUMP_INSN
1571 && prev_real_insn (JUMP_LABEL (i1
)) == e1
)
1577 if (GET_CODE (p1
) != USE
&& GET_CODE (p1
) != CLOBBER
)
1579 /* Ok, this insn is potentially includable in a cross-jump here. */
1580 afterlast1
= last1
, afterlast2
= last2
;
1581 last1
= i1
, last2
= i2
, --minimum
;
1585 if (minimum
<= 0 && last1
!= 0 && last1
!= e1
)
1586 *f1
= last1
, *f2
= last2
;
1590 do_cross_jump (insn
, newjpos
, newlpos
)
1591 rtx insn
, newjpos
, newlpos
;
1593 /* Find an existing label at this point
1594 or make a new one if there is none. */
1595 register rtx label
= get_label_before (newlpos
);
1597 /* Make the same jump insn jump to the new point. */
1598 if (GET_CODE (PATTERN (insn
)) == RETURN
)
1600 /* Remove from jump chain of returns. */
1601 delete_from_jump_chain (insn
);
1602 /* Change the insn. */
1603 PATTERN (insn
) = gen_jump (label
);
1604 INSN_CODE (insn
) = -1;
1605 JUMP_LABEL (insn
) = label
;
1606 LABEL_NUSES (label
)++;
1607 /* Add to new the jump chain. */
1608 if (INSN_UID (label
) < max_jump_chain
1609 && INSN_UID (insn
) < max_jump_chain
)
1611 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (label
)];
1612 jump_chain
[INSN_UID (label
)] = insn
;
1616 redirect_jump (insn
, label
);
1618 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1619 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1620 the NEWJPOS stream. */
1622 while (newjpos
!= insn
)
1626 for (lnote
= REG_NOTES (newlpos
); lnote
; lnote
= XEXP (lnote
, 1))
1627 if ((REG_NOTE_KIND (lnote
) == REG_EQUAL
1628 || REG_NOTE_KIND (lnote
) == REG_EQUIV
)
1629 && ! find_reg_note (newjpos
, REG_EQUAL
, XEXP (lnote
, 0))
1630 && ! find_reg_note (newjpos
, REG_EQUIV
, XEXP (lnote
, 0)))
1631 remove_note (newlpos
, lnote
);
1633 delete_insn (newjpos
);
1634 newjpos
= next_real_insn (newjpos
);
1635 newlpos
= next_real_insn (newlpos
);
1639 /* Return the label before INSN, or put a new label there. */
1642 get_label_before (insn
)
1647 /* Find an existing label at this point
1648 or make a new one if there is none. */
1649 label
= prev_nonnote_insn (insn
);
1651 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
1653 rtx prev
= PREV_INSN (insn
);
1655 label
= gen_label_rtx ();
1656 emit_label_after (label
, prev
);
1657 LABEL_NUSES (label
) = 0;
1662 /* Return the label after INSN, or put a new label there. */
1665 get_label_after (insn
)
1670 /* Find an existing label at this point
1671 or make a new one if there is none. */
1672 label
= next_nonnote_insn (insn
);
1674 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
1676 label
= gen_label_rtx ();
1677 emit_label_after (label
, insn
);
1678 LABEL_NUSES (label
) = 0;
1683 /* Return 1 if INSN is a jump that jumps to right after TARGET
1684 only on the condition that TARGET itself would drop through.
1685 Assumes that TARGET is a conditional jump. */
1688 jump_back_p (insn
, target
)
1692 enum rtx_code codei
, codet
;
1694 if (simplejump_p (insn
) || ! condjump_p (insn
)
1695 || simplejump_p (target
)
1696 || target
!= prev_real_insn (JUMP_LABEL (insn
)))
1699 cinsn
= XEXP (SET_SRC (PATTERN (insn
)), 0);
1700 ctarget
= XEXP (SET_SRC (PATTERN (target
)), 0);
1702 codei
= GET_CODE (cinsn
);
1703 codet
= GET_CODE (ctarget
);
1705 if (XEXP (SET_SRC (PATTERN (insn
)), 1) == pc_rtx
)
1707 if (! can_reverse_comparison_p (cinsn
, insn
))
1709 codei
= reverse_condition (codei
);
1712 if (XEXP (SET_SRC (PATTERN (target
)), 2) == pc_rtx
)
1714 if (! can_reverse_comparison_p (ctarget
, target
))
1716 codet
= reverse_condition (codet
);
1719 return (codei
== codet
1720 && rtx_renumbered_equal_p (XEXP (cinsn
, 0), XEXP (ctarget
, 0))
1721 && rtx_renumbered_equal_p (XEXP (cinsn
, 1), XEXP (ctarget
, 1)));
1724 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
1725 return non-zero if it is safe to reverse this comparison. It is if our
1726 floating-point is not IEEE, if this is an NE or EQ comparison, or if
1727 this is known to be an integer comparison. */
1730 can_reverse_comparison_p (comparison
, insn
)
1736 /* If this is not actually a comparison, we can't reverse it. */
1737 if (GET_RTX_CLASS (GET_CODE (comparison
)) != '<')
1740 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
1741 /* If this is an NE comparison, it is safe to reverse it to an EQ
1742 comparison and vice versa, even for floating point. If no operands
1743 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
1744 always false and NE is always true, so the reversal is also valid. */
1746 || GET_CODE (comparison
) == NE
1747 || GET_CODE (comparison
) == EQ
)
1750 arg0
= XEXP (comparison
, 0);
1752 /* Make sure ARG0 is one of the actual objects being compared. If we
1753 can't do this, we can't be sure the comparison can be reversed.
1755 Handle cc0 and a MODE_CC register. */
1756 if ((GET_CODE (arg0
) == REG
&& GET_MODE_CLASS (GET_MODE (arg0
)) == MODE_CC
)
1762 rtx prev
= prev_nonnote_insn (insn
);
1765 /* First see if the condition code mode alone if enough to say we can
1766 reverse the condition. If not, then search backwards for a set of
1767 ARG0. We do not need to check for an insn clobbering it since valid
1768 code will contain set a set with no intervening clobber. But
1769 stop when we reach a label. */
1770 #ifdef REVERSIBLE_CC_MODE
1771 if (GET_MODE_CLASS (GET_MODE (arg0
)) == MODE_CC
1772 && REVERSIBLE_CC_MODE (GET_MODE (arg0
)))
1776 for (prev
= prev_nonnote_insn (insn
);
1777 prev
!= 0 && GET_CODE (prev
) != CODE_LABEL
;
1778 prev
= prev_nonnote_insn (prev
))
1779 if ((set
= single_set (prev
)) != 0
1780 && rtx_equal_p (SET_DEST (set
), arg0
))
1782 arg0
= SET_SRC (set
);
1784 if (GET_CODE (arg0
) == COMPARE
)
1785 arg0
= XEXP (arg0
, 0);
1790 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
1791 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
1792 return (GET_CODE (arg0
) == CONST_INT
1793 || (GET_MODE (arg0
) != VOIDmode
1794 && GET_MODE_CLASS (GET_MODE (arg0
)) != MODE_CC
1795 && GET_MODE_CLASS (GET_MODE (arg0
)) != MODE_FLOAT
));
1798 /* Given an rtx-code for a comparison, return the code for the negated
1799 comparison. If no such code exists, return UNKNOWN.
1801 WATCH OUT! reverse_condition is not safe to use on a jump that might
1802 be acting on the results of an IEEE floating point comparison, because
1803 of the special treatment of non-signaling nans in comparisons.
1804 Use can_reverse_comparison_p to be sure. */
1807 reverse_condition (code
)
1850 /* Similar, but we're allowed to generate unordered comparisons, which
1851 makes it safe for IEEE floating-point. Of course, we have to recognize
1852 that the target will support them too... */
1855 reverse_condition_maybe_unordered (code
)
1858 /* Non-IEEE formats don't have unordered conditions. */
1859 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
)
1860 return reverse_condition (code
);
1906 /* Similar, but return the code when two operands of a comparison are swapped.
1907 This IS safe for IEEE floating-point. */
1910 swap_condition (code
)
1953 /* Given a comparison CODE, return the corresponding unsigned comparison.
1954 If CODE is an equality comparison or already an unsigned comparison,
1955 CODE is returned. */
1958 unsigned_condition (code
)
1985 /* Similarly, return the signed version of a comparison. */
1988 signed_condition (code
)
2015 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
2016 truth of CODE1 implies the truth of CODE2. */
2019 comparison_dominates_p (code1
, code2
)
2020 enum rtx_code code1
, code2
;
2028 if (code2
== LE
|| code2
== LEU
|| code2
== GE
|| code2
== GEU
2029 || code2
== ORDERED
)
2034 if (code2
== LE
|| code2
== NE
|| code2
== ORDERED
)
2039 if (code2
== GE
|| code2
== NE
|| code2
== ORDERED
)
2045 if (code2
== ORDERED
)
2050 if (code2
== NE
|| code2
== ORDERED
)
2055 if (code2
== LEU
|| code2
== NE
)
2060 if (code2
== GEU
|| code2
== NE
)
2076 /* Return 1 if INSN is an unconditional jump and nothing else. */
2082 return (GET_CODE (insn
) == JUMP_INSN
2083 && GET_CODE (PATTERN (insn
)) == SET
2084 && GET_CODE (SET_DEST (PATTERN (insn
))) == PC
2085 && GET_CODE (SET_SRC (PATTERN (insn
))) == LABEL_REF
);
2088 /* Return nonzero if INSN is a (possibly) conditional jump
2089 and nothing more. */
2095 register rtx x
= PATTERN (insn
);
2097 if (GET_CODE (x
) != SET
2098 || GET_CODE (SET_DEST (x
)) != PC
)
2102 if (GET_CODE (x
) == LABEL_REF
)
2104 else return (GET_CODE (x
) == IF_THEN_ELSE
2105 && ((GET_CODE (XEXP (x
, 2)) == PC
2106 && (GET_CODE (XEXP (x
, 1)) == LABEL_REF
2107 || GET_CODE (XEXP (x
, 1)) == RETURN
))
2108 || (GET_CODE (XEXP (x
, 1)) == PC
2109 && (GET_CODE (XEXP (x
, 2)) == LABEL_REF
2110 || GET_CODE (XEXP (x
, 2)) == RETURN
))));
2115 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2119 condjump_in_parallel_p (insn
)
2122 register rtx x
= PATTERN (insn
);
2124 if (GET_CODE (x
) != PARALLEL
)
2127 x
= XVECEXP (x
, 0, 0);
2129 if (GET_CODE (x
) != SET
)
2131 if (GET_CODE (SET_DEST (x
)) != PC
)
2133 if (GET_CODE (SET_SRC (x
)) == LABEL_REF
)
2135 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
2137 if (XEXP (SET_SRC (x
), 2) == pc_rtx
2138 && (GET_CODE (XEXP (SET_SRC (x
), 1)) == LABEL_REF
2139 || GET_CODE (XEXP (SET_SRC (x
), 1)) == RETURN
))
2141 if (XEXP (SET_SRC (x
), 1) == pc_rtx
2142 && (GET_CODE (XEXP (SET_SRC (x
), 2)) == LABEL_REF
2143 || GET_CODE (XEXP (SET_SRC (x
), 2)) == RETURN
))
2148 /* Return the label of a conditional jump. */
2151 condjump_label (insn
)
2154 register rtx x
= PATTERN (insn
);
2156 if (GET_CODE (x
) == PARALLEL
)
2157 x
= XVECEXP (x
, 0, 0);
2158 if (GET_CODE (x
) != SET
)
2160 if (GET_CODE (SET_DEST (x
)) != PC
)
2163 if (GET_CODE (x
) == LABEL_REF
)
2165 if (GET_CODE (x
) != IF_THEN_ELSE
)
2167 if (XEXP (x
, 2) == pc_rtx
&& GET_CODE (XEXP (x
, 1)) == LABEL_REF
)
2169 if (XEXP (x
, 1) == pc_rtx
&& GET_CODE (XEXP (x
, 2)) == LABEL_REF
)
2174 /* Return true if INSN is a (possibly conditional) return insn. */
2177 returnjump_p_1 (loc
, data
)
2179 void *data ATTRIBUTE_UNUSED
;
2182 return x
&& GET_CODE (x
) == RETURN
;
2189 return for_each_rtx (&PATTERN (insn
), returnjump_p_1
, NULL
);
2192 /* Return true if INSN is a jump that only transfers control and
2201 if (GET_CODE (insn
) != JUMP_INSN
)
2204 set
= single_set (insn
);
2207 if (GET_CODE (SET_DEST (set
)) != PC
)
2209 if (side_effects_p (SET_SRC (set
)))
2217 /* Return 1 if X is an RTX that does nothing but set the condition codes
2218 and CLOBBER or USE registers.
2219 Return -1 if X does explicitly set the condition codes,
2220 but also does other things. */
2224 rtx x ATTRIBUTE_UNUSED
;
2226 if (GET_CODE (x
) == SET
&& SET_DEST (x
) == cc0_rtx
)
2228 if (GET_CODE (x
) == PARALLEL
)
2232 int other_things
= 0;
2233 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2235 if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
2236 && SET_DEST (XVECEXP (x
, 0, i
)) == cc0_rtx
)
2238 else if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
)
2241 return ! sets_cc0
? 0 : other_things
? -1 : 1;
2247 /* Follow any unconditional jump at LABEL;
2248 return the ultimate label reached by any such chain of jumps.
2249 If LABEL is not followed by a jump, return LABEL.
2250 If the chain loops or we can't find end, return LABEL,
2251 since that tells caller to avoid changing the insn.
2253 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2254 a USE or CLOBBER. */
2257 follow_jumps (label
)
2262 register rtx value
= label
;
2267 && (insn
= next_active_insn (value
)) != 0
2268 && GET_CODE (insn
) == JUMP_INSN
2269 && ((JUMP_LABEL (insn
) != 0 && simplejump_p (insn
))
2270 || GET_CODE (PATTERN (insn
)) == RETURN
)
2271 && (next
= NEXT_INSN (insn
))
2272 && GET_CODE (next
) == BARRIER
);
2275 /* Don't chain through the insn that jumps into a loop
2276 from outside the loop,
2277 since that would create multiple loop entry jumps
2278 and prevent loop optimization. */
2280 if (!reload_completed
)
2281 for (tem
= value
; tem
!= insn
; tem
= NEXT_INSN (tem
))
2282 if (GET_CODE (tem
) == NOTE
2283 && (NOTE_LINE_NUMBER (tem
) == NOTE_INSN_LOOP_BEG
2284 /* ??? Optional. Disables some optimizations, but makes
2285 gcov output more accurate with -O. */
2286 || (flag_test_coverage
&& NOTE_LINE_NUMBER (tem
) > 0)))
2289 /* If we have found a cycle, make the insn jump to itself. */
2290 if (JUMP_LABEL (insn
) == label
)
2293 tem
= next_active_insn (JUMP_LABEL (insn
));
2294 if (tem
&& (GET_CODE (PATTERN (tem
)) == ADDR_VEC
2295 || GET_CODE (PATTERN (tem
)) == ADDR_DIFF_VEC
))
2298 value
= JUMP_LABEL (insn
);
2305 /* Assuming that field IDX of X is a vector of label_refs,
2306 replace each of them by the ultimate label reached by it.
2307 Return nonzero if a change is made.
2308 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2311 tension_vector_labels (x
, idx
)
2317 for (i
= XVECLEN (x
, idx
) - 1; i
>= 0; i
--)
2319 register rtx olabel
= XEXP (XVECEXP (x
, idx
, i
), 0);
2320 register rtx nlabel
= follow_jumps (olabel
);
2321 if (nlabel
&& nlabel
!= olabel
)
2323 XEXP (XVECEXP (x
, idx
, i
), 0) = nlabel
;
2324 ++LABEL_NUSES (nlabel
);
2325 if (--LABEL_NUSES (olabel
) == 0)
2326 delete_insn (olabel
);
2333 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2334 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2335 in INSN, then store one of them in JUMP_LABEL (INSN).
2336 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2337 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2338 Also, when there are consecutive labels, canonicalize on the last of them.
2340 Note that two labels separated by a loop-beginning note
2341 must be kept distinct if we have not yet done loop-optimization,
2342 because the gap between them is where loop-optimize
2343 will want to move invariant code to. CROSS_JUMP tells us
2344 that loop-optimization is done with.
2346 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2347 two labels distinct if they are separated by only USE or CLOBBER insns. */
2350 mark_jump_label (x
, insn
, cross_jump
, in_mem
)
2356 register RTX_CODE code
= GET_CODE (x
);
2358 register const char *fmt
;
2380 /* If this is a constant-pool reference, see if it is a label. */
2381 if (CONSTANT_POOL_ADDRESS_P (x
))
2382 mark_jump_label (get_pool_constant (x
), insn
, cross_jump
, in_mem
);
2387 rtx label
= XEXP (x
, 0);
2392 if (GET_CODE (label
) != CODE_LABEL
)
2395 /* Ignore references to labels of containing functions. */
2396 if (LABEL_REF_NONLOCAL_P (x
))
2399 /* If there are other labels following this one,
2400 replace it with the last of the consecutive labels. */
2401 for (next
= NEXT_INSN (label
); next
; next
= NEXT_INSN (next
))
2403 if (GET_CODE (next
) == CODE_LABEL
)
2405 else if (cross_jump
&& GET_CODE (next
) == INSN
2406 && (GET_CODE (PATTERN (next
)) == USE
2407 || GET_CODE (PATTERN (next
)) == CLOBBER
))
2409 else if (GET_CODE (next
) != NOTE
)
2411 else if (! cross_jump
2412 && (NOTE_LINE_NUMBER (next
) == NOTE_INSN_LOOP_BEG
2413 || NOTE_LINE_NUMBER (next
) == NOTE_INSN_FUNCTION_END
2414 /* ??? Optional. Disables some optimizations, but
2415 makes gcov output more accurate with -O. */
2416 || (flag_test_coverage
&& NOTE_LINE_NUMBER (next
) > 0)))
2420 XEXP (x
, 0) = label
;
2421 if (! insn
|| ! INSN_DELETED_P (insn
))
2422 ++LABEL_NUSES (label
);
2426 if (GET_CODE (insn
) == JUMP_INSN
)
2427 JUMP_LABEL (insn
) = label
;
2429 /* If we've changed OLABEL and we had a REG_LABEL note
2430 for it, update it as well. */
2431 else if (label
!= olabel
2432 && (note
= find_reg_note (insn
, REG_LABEL
, olabel
)) != 0)
2433 XEXP (note
, 0) = label
;
2435 /* Otherwise, add a REG_LABEL note for LABEL unless there already
2437 else if (! find_reg_note (insn
, REG_LABEL
, label
))
2439 /* This code used to ignore labels which refered to dispatch
2440 tables to avoid flow.c generating worse code.
2442 However, in the presense of global optimizations like
2443 gcse which call find_basic_blocks without calling
2444 life_analysis, not recording such labels will lead
2445 to compiler aborts because of inconsistencies in the
2446 flow graph. So we go ahead and record the label.
2448 It may also be the case that the optimization argument
2449 is no longer valid because of the more accurate cfg
2450 we build in find_basic_blocks -- it no longer pessimizes
2451 code when it finds a REG_LABEL note. */
2452 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_LABEL
, label
,
2459 /* Do walk the labels in a vector, but not the first operand of an
2460 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2463 if (! INSN_DELETED_P (insn
))
2465 int eltnum
= code
== ADDR_DIFF_VEC
? 1 : 0;
2467 for (i
= 0; i
< XVECLEN (x
, eltnum
); i
++)
2468 mark_jump_label (XVECEXP (x
, eltnum
, i
), NULL_RTX
,
2469 cross_jump
, in_mem
);
2477 fmt
= GET_RTX_FORMAT (code
);
2478 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
2481 mark_jump_label (XEXP (x
, i
), insn
, cross_jump
, in_mem
);
2482 else if (fmt
[i
] == 'E')
2485 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
2486 mark_jump_label (XVECEXP (x
, i
, j
), insn
, cross_jump
, in_mem
);
2491 /* If all INSN does is set the pc, delete it,
2492 and delete the insn that set the condition codes for it
2493 if that's what the previous thing was. */
2499 register rtx set
= single_set (insn
);
2501 if (set
&& GET_CODE (SET_DEST (set
)) == PC
)
2502 delete_computation (insn
);
2505 /* Verify INSN is a BARRIER and delete it. */
2508 delete_barrier (insn
)
2511 if (GET_CODE (insn
) != BARRIER
)
2517 /* Recursively delete prior insns that compute the value (used only by INSN
2518 which the caller is deleting) stored in the register mentioned by NOTE
2519 which is a REG_DEAD note associated with INSN. */
2522 delete_prior_computation (note
, insn
)
2527 rtx reg
= XEXP (note
, 0);
2529 for (our_prev
= prev_nonnote_insn (insn
);
2530 our_prev
&& (GET_CODE (our_prev
) == INSN
2531 || GET_CODE (our_prev
) == CALL_INSN
);
2532 our_prev
= prev_nonnote_insn (our_prev
))
2534 rtx pat
= PATTERN (our_prev
);
2536 /* If we reach a CALL which is not calling a const function
2537 or the callee pops the arguments, then give up. */
2538 if (GET_CODE (our_prev
) == CALL_INSN
2539 && (! CONST_CALL_P (our_prev
)
2540 || GET_CODE (pat
) != SET
|| GET_CODE (SET_SRC (pat
)) != CALL
))
2543 /* If we reach a SEQUENCE, it is too complex to try to
2544 do anything with it, so give up. */
2545 if (GET_CODE (pat
) == SEQUENCE
)
2548 if (GET_CODE (pat
) == USE
2549 && GET_CODE (XEXP (pat
, 0)) == INSN
)
2550 /* reorg creates USEs that look like this. We leave them
2551 alone because reorg needs them for its own purposes. */
2554 if (reg_set_p (reg
, pat
))
2556 if (side_effects_p (pat
) && GET_CODE (our_prev
) != CALL_INSN
)
2559 if (GET_CODE (pat
) == PARALLEL
)
2561 /* If we find a SET of something else, we can't
2566 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
2568 rtx part
= XVECEXP (pat
, 0, i
);
2570 if (GET_CODE (part
) == SET
2571 && SET_DEST (part
) != reg
)
2575 if (i
== XVECLEN (pat
, 0))
2576 delete_computation (our_prev
);
2578 else if (GET_CODE (pat
) == SET
2579 && GET_CODE (SET_DEST (pat
)) == REG
)
2581 int dest_regno
= REGNO (SET_DEST (pat
));
2583 = dest_regno
+ (dest_regno
< FIRST_PSEUDO_REGISTER
2584 ? HARD_REGNO_NREGS (dest_regno
,
2585 GET_MODE (SET_DEST (pat
))) : 1);
2586 int regno
= REGNO (reg
);
2587 int endregno
= regno
+ (regno
< FIRST_PSEUDO_REGISTER
2588 ? HARD_REGNO_NREGS (regno
, GET_MODE (reg
)) : 1);
2590 if (dest_regno
>= regno
2591 && dest_endregno
<= endregno
)
2592 delete_computation (our_prev
);
2594 /* We may have a multi-word hard register and some, but not
2595 all, of the words of the register are needed in subsequent
2596 insns. Write REG_UNUSED notes for those parts that were not
2598 else if (dest_regno
<= regno
2599 && dest_endregno
>= endregno
)
2603 REG_NOTES (our_prev
)
2604 = gen_rtx_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (our_prev
));
2606 for (i
= dest_regno
; i
< dest_endregno
; i
++)
2607 if (! find_regno_note (our_prev
, REG_UNUSED
, i
))
2610 if (i
== dest_endregno
)
2611 delete_computation (our_prev
);
2618 /* If PAT references the register that dies here, it is an
2619 additional use. Hence any prior SET isn't dead. However, this
2620 insn becomes the new place for the REG_DEAD note. */
2621 if (reg_overlap_mentioned_p (reg
, pat
))
2623 XEXP (note
, 1) = REG_NOTES (our_prev
);
2624 REG_NOTES (our_prev
) = note
;
2630 /* Delete INSN and recursively delete insns that compute values used only
2631 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2632 If we are running before flow.c, we need do nothing since flow.c will
2633 delete dead code. We also can't know if the registers being used are
2634 dead or not at this point.
2636 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2637 nothing other than set a register that dies in this insn, we can delete
2640 On machines with CC0, if CC0 is used in this insn, we may be able to
2641 delete the insn that set it. */
2644 delete_computation (insn
)
2651 if (reg_referenced_p (cc0_rtx
, PATTERN (insn
)))
2653 rtx prev
= prev_nonnote_insn (insn
);
2654 /* We assume that at this stage
2655 CC's are always set explicitly
2656 and always immediately before the jump that
2657 will use them. So if the previous insn
2658 exists to set the CC's, delete it
2659 (unless it performs auto-increments, etc.). */
2660 if (prev
&& GET_CODE (prev
) == INSN
2661 && sets_cc0_p (PATTERN (prev
)))
2663 if (sets_cc0_p (PATTERN (prev
)) > 0
2664 && ! side_effects_p (PATTERN (prev
)))
2665 delete_computation (prev
);
2667 /* Otherwise, show that cc0 won't be used. */
2668 REG_NOTES (prev
) = gen_rtx_EXPR_LIST (REG_UNUSED
,
2669 cc0_rtx
, REG_NOTES (prev
));
2674 #ifdef INSN_SCHEDULING
2675 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
2676 reload has completed. The schedulers need to be fixed. Until
2677 they are, we must not rely on the death notes here. */
2678 if (reload_completed
&& flag_schedule_insns_after_reload
)
2685 /* The REG_DEAD note may have been omitted for a register
2686 which is both set and used by the insn. */
2687 set
= single_set (insn
);
2688 if (set
&& GET_CODE (SET_DEST (set
)) == REG
)
2690 int dest_regno
= REGNO (SET_DEST (set
));
2692 = dest_regno
+ (dest_regno
< FIRST_PSEUDO_REGISTER
2693 ? HARD_REGNO_NREGS (dest_regno
,
2694 GET_MODE (SET_DEST (set
))) : 1);
2697 for (i
= dest_regno
; i
< dest_endregno
; i
++)
2699 if (! refers_to_regno_p (i
, i
+ 1, SET_SRC (set
), NULL_PTR
)
2700 || find_regno_note (insn
, REG_DEAD
, i
))
2703 note
= gen_rtx_EXPR_LIST (REG_DEAD
, (i
< FIRST_PSEUDO_REGISTER
2704 ? gen_rtx_REG (reg_raw_mode
[i
], i
)
2705 : SET_DEST (set
)), NULL_RTX
);
2706 delete_prior_computation (note
, insn
);
2710 for (note
= REG_NOTES (insn
); note
; note
= next
)
2712 next
= XEXP (note
, 1);
2714 if (REG_NOTE_KIND (note
) != REG_DEAD
2715 /* Verify that the REG_NOTE is legitimate. */
2716 || GET_CODE (XEXP (note
, 0)) != REG
)
2719 delete_prior_computation (note
, insn
);
2725 /* Delete insn INSN from the chain of insns and update label ref counts.
2726 May delete some following insns as a consequence; may even delete
2727 a label elsewhere and insns that follow it.
2729 Returns the first insn after INSN that was not deleted. */
2735 register rtx next
= NEXT_INSN (insn
);
2736 register rtx prev
= PREV_INSN (insn
);
2737 register int was_code_label
= (GET_CODE (insn
) == CODE_LABEL
);
2738 register int dont_really_delete
= 0;
2740 while (next
&& INSN_DELETED_P (next
))
2741 next
= NEXT_INSN (next
);
2743 /* This insn is already deleted => return first following nondeleted. */
2744 if (INSN_DELETED_P (insn
))
2748 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
2750 /* Don't delete user-declared labels. When optimizing, convert them
2751 to special NOTEs instead. When not optimizing, leave them alone. */
2752 if (was_code_label
&& LABEL_NAME (insn
) != 0)
2755 dont_really_delete
= 1;
2756 else if (! dont_really_delete
)
2758 PUT_CODE (insn
, NOTE
);
2759 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED_LABEL
;
2760 NOTE_SOURCE_FILE (insn
) = 0;
2761 dont_really_delete
= 1;
2765 /* Mark this insn as deleted. */
2766 INSN_DELETED_P (insn
) = 1;
2768 /* If this is an unconditional jump, delete it from the jump chain. */
2769 if (simplejump_p (insn
))
2770 delete_from_jump_chain (insn
);
2772 /* If instruction is followed by a barrier,
2773 delete the barrier too. */
2775 if (next
!= 0 && GET_CODE (next
) == BARRIER
)
2777 INSN_DELETED_P (next
) = 1;
2778 next
= NEXT_INSN (next
);
2781 /* Patch out INSN (and the barrier if any) */
2783 if (! dont_really_delete
)
2787 NEXT_INSN (prev
) = next
;
2788 if (GET_CODE (prev
) == INSN
&& GET_CODE (PATTERN (prev
)) == SEQUENCE
)
2789 NEXT_INSN (XVECEXP (PATTERN (prev
), 0,
2790 XVECLEN (PATTERN (prev
), 0) - 1)) = next
;
2795 PREV_INSN (next
) = prev
;
2796 if (GET_CODE (next
) == INSN
&& GET_CODE (PATTERN (next
)) == SEQUENCE
)
2797 PREV_INSN (XVECEXP (PATTERN (next
), 0, 0)) = prev
;
2800 if (prev
&& NEXT_INSN (prev
) == 0)
2801 set_last_insn (prev
);
2804 /* If deleting a jump, decrement the count of the label,
2805 and delete the label if it is now unused. */
2807 if (GET_CODE (insn
) == JUMP_INSN
&& JUMP_LABEL (insn
))
2809 rtx lab
= JUMP_LABEL (insn
), lab_next
;
2811 if (--LABEL_NUSES (lab
) == 0)
2813 /* This can delete NEXT or PREV,
2814 either directly if NEXT is JUMP_LABEL (INSN),
2815 or indirectly through more levels of jumps. */
2818 /* I feel a little doubtful about this loop,
2819 but I see no clean and sure alternative way
2820 to find the first insn after INSN that is not now deleted.
2821 I hope this works. */
2822 while (next
&& INSN_DELETED_P (next
))
2823 next
= NEXT_INSN (next
);
2826 else if ((lab_next
= next_nonnote_insn (lab
)) != NULL
2827 && GET_CODE (lab_next
) == JUMP_INSN
2828 && (GET_CODE (PATTERN (lab_next
)) == ADDR_VEC
2829 || GET_CODE (PATTERN (lab_next
)) == ADDR_DIFF_VEC
))
2831 /* If we're deleting the tablejump, delete the dispatch table.
2832 We may not be able to kill the label immediately preceeding
2833 just yet, as it might be referenced in code leading up to
2835 delete_insn (lab_next
);
2839 /* Likewise if we're deleting a dispatch table. */
2841 if (GET_CODE (insn
) == JUMP_INSN
2842 && (GET_CODE (PATTERN (insn
)) == ADDR_VEC
2843 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
))
2845 rtx pat
= PATTERN (insn
);
2846 int i
, diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
2847 int len
= XVECLEN (pat
, diff_vec_p
);
2849 for (i
= 0; i
< len
; i
++)
2850 if (--LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)) == 0)
2851 delete_insn (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0));
2852 while (next
&& INSN_DELETED_P (next
))
2853 next
= NEXT_INSN (next
);
2857 while (prev
&& (INSN_DELETED_P (prev
) || GET_CODE (prev
) == NOTE
))
2858 prev
= PREV_INSN (prev
);
2860 /* If INSN was a label and a dispatch table follows it,
2861 delete the dispatch table. The tablejump must have gone already.
2862 It isn't useful to fall through into a table. */
2865 && NEXT_INSN (insn
) != 0
2866 && GET_CODE (NEXT_INSN (insn
)) == JUMP_INSN
2867 && (GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_VEC
2868 || GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_DIFF_VEC
))
2869 next
= delete_insn (NEXT_INSN (insn
));
2871 /* If INSN was a label, delete insns following it if now unreachable. */
2873 if (was_code_label
&& prev
&& GET_CODE (prev
) == BARRIER
)
2875 register RTX_CODE code
;
2877 && (GET_RTX_CLASS (code
= GET_CODE (next
)) == 'i'
2878 || code
== NOTE
|| code
== BARRIER
2879 || (code
== CODE_LABEL
&& INSN_DELETED_P (next
))))
2882 && NOTE_LINE_NUMBER (next
) != NOTE_INSN_FUNCTION_END
)
2883 next
= NEXT_INSN (next
);
2884 /* Keep going past other deleted labels to delete what follows. */
2885 else if (code
== CODE_LABEL
&& INSN_DELETED_P (next
))
2886 next
= NEXT_INSN (next
);
2888 /* Note: if this deletes a jump, it can cause more
2889 deletion of unreachable code, after a different label.
2890 As long as the value from this recursive call is correct,
2891 this invocation functions correctly. */
2892 next
= delete_insn (next
);
2899 /* Advance from INSN till reaching something not deleted
2900 then return that. May return INSN itself. */
2903 next_nondeleted_insn (insn
)
2906 while (INSN_DELETED_P (insn
))
2907 insn
= NEXT_INSN (insn
);
2911 /* Delete a range of insns from FROM to TO, inclusive.
2912 This is for the sake of peephole optimization, so assume
2913 that whatever these insns do will still be done by a new
2914 peephole insn that will replace them. */
2917 delete_for_peephole (from
, to
)
2918 register rtx from
, to
;
2920 register rtx insn
= from
;
2924 register rtx next
= NEXT_INSN (insn
);
2925 register rtx prev
= PREV_INSN (insn
);
2927 if (GET_CODE (insn
) != NOTE
)
2929 INSN_DELETED_P (insn
) = 1;
2931 /* Patch this insn out of the chain. */
2932 /* We don't do this all at once, because we
2933 must preserve all NOTEs. */
2935 NEXT_INSN (prev
) = next
;
2938 PREV_INSN (next
) = prev
;
2946 /* Note that if TO is an unconditional jump
2947 we *do not* delete the BARRIER that follows,
2948 since the peephole that replaces this sequence
2949 is also an unconditional jump in that case. */
2952 /* We have determined that INSN is never reached, and are about to
2953 delete it. Print a warning if the user asked for one.
2955 To try to make this warning more useful, this should only be called
2956 once per basic block not reached, and it only warns when the basic
2957 block contains more than one line from the current function, and
2958 contains at least one operation. CSE and inlining can duplicate insns,
2959 so it's possible to get spurious warnings from this. */
2962 never_reached_warning (avoided_insn
)
2966 rtx a_line_note
= NULL
;
2967 int two_avoided_lines
= 0;
2968 int contains_insn
= 0;
2970 if (! warn_notreached
)
2973 /* Scan forwards, looking at LINE_NUMBER notes, until
2974 we hit a LABEL or we run out of insns. */
2976 for (insn
= avoided_insn
; insn
!= NULL
; insn
= NEXT_INSN (insn
))
2978 if (GET_CODE (insn
) == CODE_LABEL
)
2980 else if (GET_CODE (insn
) == NOTE
/* A line number note? */
2981 && NOTE_LINE_NUMBER (insn
) >= 0)
2983 if (a_line_note
== NULL
)
2986 two_avoided_lines
|= (NOTE_LINE_NUMBER (a_line_note
)
2987 != NOTE_LINE_NUMBER (insn
));
2989 else if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
2992 if (two_avoided_lines
&& contains_insn
)
2993 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note
),
2994 NOTE_LINE_NUMBER (a_line_note
),
2995 "will never be executed");
2998 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
2999 NLABEL as a return. Accrue modifications into the change group. */
3002 redirect_exp_1 (loc
, olabel
, nlabel
, insn
)
3007 register rtx x
= *loc
;
3008 register RTX_CODE code
= GET_CODE (x
);
3010 register const char *fmt
;
3012 if (code
== LABEL_REF
)
3014 if (XEXP (x
, 0) == olabel
)
3018 n
= gen_rtx_LABEL_REF (VOIDmode
, nlabel
);
3020 n
= gen_rtx_RETURN (VOIDmode
);
3022 validate_change (insn
, loc
, n
, 1);
3026 else if (code
== RETURN
&& olabel
== 0)
3028 x
= gen_rtx_LABEL_REF (VOIDmode
, nlabel
);
3029 if (loc
== &PATTERN (insn
))
3030 x
= gen_rtx_SET (VOIDmode
, pc_rtx
, x
);
3031 validate_change (insn
, loc
, x
, 1);
3035 if (code
== SET
&& nlabel
== 0 && SET_DEST (x
) == pc_rtx
3036 && GET_CODE (SET_SRC (x
)) == LABEL_REF
3037 && XEXP (SET_SRC (x
), 0) == olabel
)
3039 validate_change (insn
, loc
, gen_rtx_RETURN (VOIDmode
), 1);
3043 fmt
= GET_RTX_FORMAT (code
);
3044 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3047 redirect_exp_1 (&XEXP (x
, i
), olabel
, nlabel
, insn
);
3048 else if (fmt
[i
] == 'E')
3051 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3052 redirect_exp_1 (&XVECEXP (x
, i
, j
), olabel
, nlabel
, insn
);
3057 /* Similar, but apply the change group and report success or failure. */
3060 redirect_exp (loc
, olabel
, nlabel
, insn
)
3065 redirect_exp_1 (loc
, olabel
, nlabel
, insn
);
3066 if (num_validated_changes () == 0)
3069 return apply_change_group ();
3072 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3073 the modifications into the change group. Return false if we did
3074 not see how to do that. */
3077 redirect_jump_1 (jump
, nlabel
)
3080 int ochanges
= num_validated_changes ();
3081 redirect_exp_1 (&PATTERN (jump
), JUMP_LABEL (jump
), nlabel
, jump
);
3082 return num_validated_changes () > ochanges
;
3085 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3086 jump target label is unused as a result, it and the code following
3089 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3092 The return value will be 1 if the change was made, 0 if it wasn't
3093 (this can only occur for NLABEL == 0). */
3096 redirect_jump (jump
, nlabel
)
3099 register rtx olabel
= JUMP_LABEL (jump
);
3101 if (nlabel
== olabel
)
3104 if (! redirect_exp (&PATTERN (jump
), olabel
, nlabel
, jump
))
3107 /* If this is an unconditional branch, delete it from the jump_chain of
3108 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3109 have UID's in range and JUMP_CHAIN is valid). */
3110 if (jump_chain
&& (simplejump_p (jump
)
3111 || GET_CODE (PATTERN (jump
)) == RETURN
))
3113 int label_index
= nlabel
? INSN_UID (nlabel
) : 0;
3115 delete_from_jump_chain (jump
);
3116 if (label_index
< max_jump_chain
3117 && INSN_UID (jump
) < max_jump_chain
)
3119 jump_chain
[INSN_UID (jump
)] = jump_chain
[label_index
];
3120 jump_chain
[label_index
] = jump
;
3124 JUMP_LABEL (jump
) = nlabel
;
3126 ++LABEL_NUSES (nlabel
);
3128 /* If we're eliding the jump over exception cleanups at the end of a
3129 function, move the function end note so that -Wreturn-type works. */
3130 if (olabel
&& NEXT_INSN (olabel
)
3131 && GET_CODE (NEXT_INSN (olabel
)) == NOTE
3132 && NOTE_LINE_NUMBER (NEXT_INSN (olabel
)) == NOTE_INSN_FUNCTION_END
)
3133 emit_note_after (NOTE_INSN_FUNCTION_END
, nlabel
);
3135 if (olabel
&& --LABEL_NUSES (olabel
) == 0)
3136 delete_insn (olabel
);
3141 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3142 Accrue the modifications into the change group. */
3145 invert_exp_1 (x
, insn
)
3149 register RTX_CODE code
;
3151 register const char *fmt
;
3153 code
= GET_CODE (x
);
3155 if (code
== IF_THEN_ELSE
)
3157 register rtx comp
= XEXP (x
, 0);
3160 /* We can do this in two ways: The preferable way, which can only
3161 be done if this is not an integer comparison, is to reverse
3162 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3163 of the IF_THEN_ELSE. If we can't do either, fail. */
3165 if (can_reverse_comparison_p (comp
, insn
))
3167 validate_change (insn
, &XEXP (x
, 0),
3168 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp
)),
3169 GET_MODE (comp
), XEXP (comp
, 0),
3176 validate_change (insn
, &XEXP (x
, 1), XEXP (x
, 2), 1);
3177 validate_change (insn
, &XEXP (x
, 2), tem
, 1);
3181 fmt
= GET_RTX_FORMAT (code
);
3182 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3185 invert_exp_1 (XEXP (x
, i
), insn
);
3186 else if (fmt
[i
] == 'E')
3189 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3190 invert_exp_1 (XVECEXP (x
, i
, j
), insn
);
3195 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3197 Return 1 if we can do so, 0 if we cannot find a way to do so that
3198 matches a pattern. */
3201 invert_exp (x
, insn
)
3205 invert_exp_1 (x
, insn
);
3206 if (num_validated_changes () == 0)
3209 return apply_change_group ();
3212 /* Invert the condition of the jump JUMP, and make it jump to label
3213 NLABEL instead of where it jumps now. Accrue changes into the
3214 change group. Return false if we didn't see how to perform the
3215 inversion and redirection. */
3218 invert_jump_1 (jump
, nlabel
)
3223 ochanges
= num_validated_changes ();
3224 invert_exp_1 (PATTERN (jump
), jump
);
3225 if (num_validated_changes () == ochanges
)
3228 return redirect_jump_1 (jump
, nlabel
);
3231 /* Invert the condition of the jump JUMP, and make it jump to label
3232 NLABEL instead of where it jumps now. Return true if successful. */
3235 invert_jump (jump
, nlabel
)
3238 /* We have to either invert the condition and change the label or
3239 do neither. Either operation could fail. We first try to invert
3240 the jump. If that succeeds, we try changing the label. If that fails,
3241 we invert the jump back to what it was. */
3243 if (! invert_exp (PATTERN (jump
), jump
))
3246 if (redirect_jump (jump
, nlabel
))
3248 /* An inverted jump means that a probability taken becomes a
3249 probability not taken. Subtract the branch probability from the
3250 probability base to convert it back to a taken probability. */
3252 rtx note
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
3254 XEXP (note
, 0) = GEN_INT (REG_BR_PROB_BASE
- INTVAL (XEXP (note
, 0)));
3259 if (! invert_exp (PATTERN (jump
), jump
))
3260 /* This should just be putting it back the way it was. */
3266 /* Delete the instruction JUMP from any jump chain it might be on. */
3269 delete_from_jump_chain (jump
)
3273 rtx olabel
= JUMP_LABEL (jump
);
3275 /* Handle unconditional jumps. */
3276 if (jump_chain
&& olabel
!= 0
3277 && INSN_UID (olabel
) < max_jump_chain
3278 && simplejump_p (jump
))
3279 index
= INSN_UID (olabel
);
3280 /* Handle return insns. */
3281 else if (jump_chain
&& GET_CODE (PATTERN (jump
)) == RETURN
)
3285 if (jump_chain
[index
] == jump
)
3286 jump_chain
[index
] = jump_chain
[INSN_UID (jump
)];
3291 for (insn
= jump_chain
[index
];
3293 insn
= jump_chain
[INSN_UID (insn
)])
3294 if (jump_chain
[INSN_UID (insn
)] == jump
)
3296 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (jump
)];
3302 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3304 If the old jump target label (before the dispatch table) becomes unused,
3305 it and the dispatch table may be deleted. In that case, find the insn
3306 before the jump references that label and delete it and logical successors
3310 redirect_tablejump (jump
, nlabel
)
3313 register rtx olabel
= JUMP_LABEL (jump
);
3315 /* Add this jump to the jump_chain of NLABEL. */
3316 if (jump_chain
&& INSN_UID (nlabel
) < max_jump_chain
3317 && INSN_UID (jump
) < max_jump_chain
)
3319 jump_chain
[INSN_UID (jump
)] = jump_chain
[INSN_UID (nlabel
)];
3320 jump_chain
[INSN_UID (nlabel
)] = jump
;
3323 PATTERN (jump
) = gen_jump (nlabel
);
3324 JUMP_LABEL (jump
) = nlabel
;
3325 ++LABEL_NUSES (nlabel
);
3326 INSN_CODE (jump
) = -1;
3328 if (--LABEL_NUSES (olabel
) == 0)
3330 delete_labelref_insn (jump
, olabel
, 0);
3331 delete_insn (olabel
);
3335 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3336 If we found one, delete it and then delete this insn if DELETE_THIS is
3337 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3340 delete_labelref_insn (insn
, label
, delete_this
)
3347 if (GET_CODE (insn
) != NOTE
3348 && reg_mentioned_p (label
, PATTERN (insn
)))
3359 for (link
= LOG_LINKS (insn
); link
; link
= XEXP (link
, 1))
3360 if (delete_labelref_insn (XEXP (link
, 0), label
, 1))
3374 /* Like rtx_equal_p except that it considers two REGs as equal
3375 if they renumber to the same value and considers two commutative
3376 operations to be the same if the order of the operands has been
3379 ??? Addition is not commutative on the PA due to the weird implicit
3380 space register selection rules for memory addresses. Therefore, we
3381 don't consider a + b == b + a.
3383 We could/should make this test a little tighter. Possibly only
3384 disabling it on the PA via some backend macro or only disabling this
3385 case when the PLUS is inside a MEM. */
3388 rtx_renumbered_equal_p (x
, y
)
3392 register RTX_CODE code
= GET_CODE (x
);
3393 register const char *fmt
;
3398 if ((code
== REG
|| (code
== SUBREG
&& GET_CODE (SUBREG_REG (x
)) == REG
))
3399 && (GET_CODE (y
) == REG
|| (GET_CODE (y
) == SUBREG
3400 && GET_CODE (SUBREG_REG (y
)) == REG
)))
3402 int reg_x
= -1, reg_y
= -1;
3403 int word_x
= 0, word_y
= 0;
3405 if (GET_MODE (x
) != GET_MODE (y
))
3408 /* If we haven't done any renumbering, don't
3409 make any assumptions. */
3410 if (reg_renumber
== 0)
3411 return rtx_equal_p (x
, y
);
3415 reg_x
= REGNO (SUBREG_REG (x
));
3416 word_x
= SUBREG_WORD (x
);
3418 if (reg_renumber
[reg_x
] >= 0)
3420 reg_x
= reg_renumber
[reg_x
] + word_x
;
3428 if (reg_renumber
[reg_x
] >= 0)
3429 reg_x
= reg_renumber
[reg_x
];
3432 if (GET_CODE (y
) == SUBREG
)
3434 reg_y
= REGNO (SUBREG_REG (y
));
3435 word_y
= SUBREG_WORD (y
);
3437 if (reg_renumber
[reg_y
] >= 0)
3439 reg_y
= reg_renumber
[reg_y
];
3447 if (reg_renumber
[reg_y
] >= 0)
3448 reg_y
= reg_renumber
[reg_y
];
3451 return reg_x
>= 0 && reg_x
== reg_y
&& word_x
== word_y
;
3454 /* Now we have disposed of all the cases
3455 in which different rtx codes can match. */
3456 if (code
!= GET_CODE (y
))
3468 return INTVAL (x
) == INTVAL (y
);
3471 /* We can't assume nonlocal labels have their following insns yet. */
3472 if (LABEL_REF_NONLOCAL_P (x
) || LABEL_REF_NONLOCAL_P (y
))
3473 return XEXP (x
, 0) == XEXP (y
, 0);
3475 /* Two label-refs are equivalent if they point at labels
3476 in the same position in the instruction stream. */
3477 return (next_real_insn (XEXP (x
, 0))
3478 == next_real_insn (XEXP (y
, 0)));
3481 return XSTR (x
, 0) == XSTR (y
, 0);
3484 /* If we didn't match EQ equality above, they aren't the same. */
3491 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3493 if (GET_MODE (x
) != GET_MODE (y
))
3496 /* For commutative operations, the RTX match if the operand match in any
3497 order. Also handle the simple binary and unary cases without a loop.
3499 ??? Don't consider PLUS a commutative operator; see comments above. */
3500 if ((code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
3502 return ((rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
3503 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)))
3504 || (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 1))
3505 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 0))));
3506 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
3507 return (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
3508 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)));
3509 else if (GET_RTX_CLASS (code
) == '1')
3510 return rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0));
3512 /* Compare the elements. If any pair of corresponding elements
3513 fail to match, return 0 for the whole things. */
3515 fmt
= GET_RTX_FORMAT (code
);
3516 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3522 if (XWINT (x
, i
) != XWINT (y
, i
))
3527 if (XINT (x
, i
) != XINT (y
, i
))
3532 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
3537 if (! rtx_renumbered_equal_p (XEXP (x
, i
), XEXP (y
, i
)))
3542 if (XEXP (x
, i
) != XEXP (y
, i
))
3549 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
3551 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
3552 if (!rtx_renumbered_equal_p (XVECEXP (x
, i
, j
), XVECEXP (y
, i
, j
)))
3563 /* If X is a hard register or equivalent to one or a subregister of one,
3564 return the hard register number. If X is a pseudo register that was not
3565 assigned a hard register, return the pseudo register number. Otherwise,
3566 return -1. Any rtx is valid for X. */
3572 if (GET_CODE (x
) == REG
)
3574 if (REGNO (x
) >= FIRST_PSEUDO_REGISTER
&& reg_renumber
[REGNO (x
)] >= 0)
3575 return reg_renumber
[REGNO (x
)];
3578 if (GET_CODE (x
) == SUBREG
)
3580 int base
= true_regnum (SUBREG_REG (x
));
3581 if (base
>= 0 && base
< FIRST_PSEUDO_REGISTER
)
3582 return SUBREG_WORD (x
) + base
;
3587 /* Optimize code of the form:
3589 for (x = a[i]; x; ...)
3591 for (x = a[i]; x; ...)
3595 Loop optimize will change the above code into
3599 { ...; if (! (x = ...)) break; }
3602 { ...; if (! (x = ...)) break; }
3605 In general, if the first test fails, the program can branch
3606 directly to `foo' and skip the second try which is doomed to fail.
3607 We run this after loop optimization and before flow analysis. */
3609 /* When comparing the insn patterns, we track the fact that different
3610 pseudo-register numbers may have been used in each computation.
3611 The following array stores an equivalence -- same_regs[I] == J means
3612 that pseudo register I was used in the first set of tests in a context
3613 where J was used in the second set. We also count the number of such
3614 pending equivalences. If nonzero, the expressions really aren't the
3617 static int *same_regs
;
3619 static int num_same_regs
;
3621 /* Track any registers modified between the target of the first jump and
3622 the second jump. They never compare equal. */
3624 static char *modified_regs
;
3626 /* Record if memory was modified. */
3628 static int modified_mem
;
3630 /* Called via note_stores on each insn between the target of the first
3631 branch and the second branch. It marks any changed registers. */
3634 mark_modified_reg (dest
, x
, data
)
3636 rtx x ATTRIBUTE_UNUSED
;
3637 void *data ATTRIBUTE_UNUSED
;
3642 if (GET_CODE (dest
) == SUBREG
)
3643 dest
= SUBREG_REG (dest
);
3645 if (GET_CODE (dest
) == MEM
)
3648 if (GET_CODE (dest
) != REG
)
3651 regno
= REGNO (dest
);
3652 if (regno
>= FIRST_PSEUDO_REGISTER
)
3653 modified_regs
[regno
] = 1;
3655 for (i
= 0; i
< HARD_REGNO_NREGS (regno
, GET_MODE (dest
)); i
++)
3656 modified_regs
[regno
+ i
] = 1;
3659 /* F is the first insn in the chain of insns. */
3662 thread_jumps (f
, max_reg
, flag_before_loop
)
3665 int flag_before_loop
;
3667 /* Basic algorithm is to find a conditional branch,
3668 the label it may branch to, and the branch after
3669 that label. If the two branches test the same condition,
3670 walk back from both branch paths until the insn patterns
3671 differ, or code labels are hit. If we make it back to
3672 the target of the first branch, then we know that the first branch
3673 will either always succeed or always fail depending on the relative
3674 senses of the two branches. So adjust the first branch accordingly
3677 rtx label
, b1
, b2
, t1
, t2
;
3678 enum rtx_code code1
, code2
;
3679 rtx b1op0
, b1op1
, b2op0
, b2op1
;
3684 /* Allocate register tables and quick-reset table. */
3685 modified_regs
= (char *) xmalloc (max_reg
* sizeof (char));
3686 same_regs
= (int *) xmalloc (max_reg
* sizeof (int));
3687 all_reset
= (int *) xmalloc (max_reg
* sizeof (int));
3688 for (i
= 0; i
< max_reg
; i
++)
3695 for (b1
= f
; b1
; b1
= NEXT_INSN (b1
))
3697 /* Get to a candidate branch insn. */
3698 if (GET_CODE (b1
) != JUMP_INSN
3699 || ! condjump_p (b1
) || simplejump_p (b1
)
3700 || JUMP_LABEL (b1
) == 0)
3703 bzero (modified_regs
, max_reg
* sizeof (char));
3706 bcopy ((char *) all_reset
, (char *) same_regs
,
3707 max_reg
* sizeof (int));
3710 label
= JUMP_LABEL (b1
);
3712 /* Look for a branch after the target. Record any registers and
3713 memory modified between the target and the branch. Stop when we
3714 get to a label since we can't know what was changed there. */
3715 for (b2
= NEXT_INSN (label
); b2
; b2
= NEXT_INSN (b2
))
3717 if (GET_CODE (b2
) == CODE_LABEL
)
3720 else if (GET_CODE (b2
) == JUMP_INSN
)
3722 /* If this is an unconditional jump and is the only use of
3723 its target label, we can follow it. */
3724 if (simplejump_p (b2
)
3725 && JUMP_LABEL (b2
) != 0
3726 && LABEL_NUSES (JUMP_LABEL (b2
)) == 1)
3728 b2
= JUMP_LABEL (b2
);
3735 if (GET_CODE (b2
) != CALL_INSN
&& GET_CODE (b2
) != INSN
)
3738 if (GET_CODE (b2
) == CALL_INSN
)
3741 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
3742 if (call_used_regs
[i
] && ! fixed_regs
[i
]
3743 && i
!= STACK_POINTER_REGNUM
3744 && i
!= FRAME_POINTER_REGNUM
3745 && i
!= HARD_FRAME_POINTER_REGNUM
3746 && i
!= ARG_POINTER_REGNUM
)
3747 modified_regs
[i
] = 1;
3750 note_stores (PATTERN (b2
), mark_modified_reg
, NULL
);
3753 /* Check the next candidate branch insn from the label
3756 || GET_CODE (b2
) != JUMP_INSN
3758 || ! condjump_p (b2
)
3759 || simplejump_p (b2
))
3762 /* Get the comparison codes and operands, reversing the
3763 codes if appropriate. If we don't have comparison codes,
3764 we can't do anything. */
3765 b1op0
= XEXP (XEXP (SET_SRC (PATTERN (b1
)), 0), 0);
3766 b1op1
= XEXP (XEXP (SET_SRC (PATTERN (b1
)), 0), 1);
3767 code1
= GET_CODE (XEXP (SET_SRC (PATTERN (b1
)), 0));
3768 if (XEXP (SET_SRC (PATTERN (b1
)), 1) == pc_rtx
)
3769 code1
= reverse_condition (code1
);
3771 b2op0
= XEXP (XEXP (SET_SRC (PATTERN (b2
)), 0), 0);
3772 b2op1
= XEXP (XEXP (SET_SRC (PATTERN (b2
)), 0), 1);
3773 code2
= GET_CODE (XEXP (SET_SRC (PATTERN (b2
)), 0));
3774 if (XEXP (SET_SRC (PATTERN (b2
)), 1) == pc_rtx
)
3775 code2
= reverse_condition (code2
);
3777 /* If they test the same things and knowing that B1 branches
3778 tells us whether or not B2 branches, check if we
3779 can thread the branch. */
3780 if (rtx_equal_for_thread_p (b1op0
, b2op0
, b2
)
3781 && rtx_equal_for_thread_p (b1op1
, b2op1
, b2
)
3782 && (comparison_dominates_p (code1
, code2
)
3783 || (can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1
)),
3786 && comparison_dominates_p (code1
, reverse_condition (code2
)))))
3789 t1
= prev_nonnote_insn (b1
);
3790 t2
= prev_nonnote_insn (b2
);
3792 while (t1
!= 0 && t2
!= 0)
3796 /* We have reached the target of the first branch.
3797 If there are no pending register equivalents,
3798 we know that this branch will either always
3799 succeed (if the senses of the two branches are
3800 the same) or always fail (if not). */
3803 if (num_same_regs
!= 0)
3806 if (comparison_dominates_p (code1
, code2
))
3807 new_label
= JUMP_LABEL (b2
);
3809 new_label
= get_label_after (b2
);
3811 if (JUMP_LABEL (b1
) != new_label
)
3813 rtx prev
= PREV_INSN (new_label
);
3815 if (flag_before_loop
3816 && GET_CODE (prev
) == NOTE
3817 && NOTE_LINE_NUMBER (prev
) == NOTE_INSN_LOOP_BEG
)
3819 /* Don't thread to the loop label. If a loop
3820 label is reused, loop optimization will
3821 be disabled for that loop. */
3822 new_label
= gen_label_rtx ();
3823 emit_label_after (new_label
, PREV_INSN (prev
));
3825 changed
|= redirect_jump (b1
, new_label
);
3830 /* If either of these is not a normal insn (it might be
3831 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
3832 have already been skipped above.) Similarly, fail
3833 if the insns are different. */
3834 if (GET_CODE (t1
) != INSN
|| GET_CODE (t2
) != INSN
3835 || recog_memoized (t1
) != recog_memoized (t2
)
3836 || ! rtx_equal_for_thread_p (PATTERN (t1
),
3840 t1
= prev_nonnote_insn (t1
);
3841 t2
= prev_nonnote_insn (t2
);
3848 free (modified_regs
);
3853 /* This is like RTX_EQUAL_P except that it knows about our handling of
3854 possibly equivalent registers and knows to consider volatile and
3855 modified objects as not equal.
3857 YINSN is the insn containing Y. */
3860 rtx_equal_for_thread_p (x
, y
, yinsn
)
3866 register enum rtx_code code
;
3867 register const char *fmt
;
3869 code
= GET_CODE (x
);
3870 /* Rtx's of different codes cannot be equal. */
3871 if (code
!= GET_CODE (y
))
3874 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
3875 (REG:SI x) and (REG:HI x) are NOT equivalent. */
3877 if (GET_MODE (x
) != GET_MODE (y
))
3880 /* For floating-point, consider everything unequal. This is a bit
3881 pessimistic, but this pass would only rarely do anything for FP
3883 if (TARGET_FLOAT_FORMAT
== IEEE_FLOAT_FORMAT
3884 && FLOAT_MODE_P (GET_MODE (x
)) && ! flag_fast_math
)
3887 /* For commutative operations, the RTX match if the operand match in any
3888 order. Also handle the simple binary and unary cases without a loop. */
3889 if (code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
3890 return ((rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
3891 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
))
3892 || (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 1), yinsn
)
3893 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 0), yinsn
)));
3894 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
3895 return (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
3896 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
));
3897 else if (GET_RTX_CLASS (code
) == '1')
3898 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
3900 /* Handle special-cases first. */
3904 if (REGNO (x
) == REGNO (y
) && ! modified_regs
[REGNO (x
)])
3907 /* If neither is user variable or hard register, check for possible
3909 if (REG_USERVAR_P (x
) || REG_USERVAR_P (y
)
3910 || REGNO (x
) < FIRST_PSEUDO_REGISTER
3911 || REGNO (y
) < FIRST_PSEUDO_REGISTER
)
3914 if (same_regs
[REGNO (x
)] == -1)
3916 same_regs
[REGNO (x
)] = REGNO (y
);
3919 /* If this is the first time we are seeing a register on the `Y'
3920 side, see if it is the last use. If not, we can't thread the
3921 jump, so mark it as not equivalent. */
3922 if (REGNO_LAST_UID (REGNO (y
)) != INSN_UID (yinsn
))
3928 return (same_regs
[REGNO (x
)] == (int) REGNO (y
));
3933 /* If memory modified or either volatile, not equivalent.
3934 Else, check address. */
3935 if (modified_mem
|| MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
3938 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
3941 if (MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
3947 /* Cancel a pending `same_regs' if setting equivalenced registers.
3948 Then process source. */
3949 if (GET_CODE (SET_DEST (x
)) == REG
3950 && GET_CODE (SET_DEST (y
)) == REG
)
3952 if (same_regs
[REGNO (SET_DEST (x
))] == (int) REGNO (SET_DEST (y
)))
3954 same_regs
[REGNO (SET_DEST (x
))] = -1;
3957 else if (REGNO (SET_DEST (x
)) != REGNO (SET_DEST (y
)))
3961 if (rtx_equal_for_thread_p (SET_DEST (x
), SET_DEST (y
), yinsn
) == 0)
3964 return rtx_equal_for_thread_p (SET_SRC (x
), SET_SRC (y
), yinsn
);
3967 return XEXP (x
, 0) == XEXP (y
, 0);
3970 return XSTR (x
, 0) == XSTR (y
, 0);
3979 fmt
= GET_RTX_FORMAT (code
);
3980 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3985 if (XWINT (x
, i
) != XWINT (y
, i
))
3991 if (XINT (x
, i
) != XINT (y
, i
))
3997 /* Two vectors must have the same length. */
3998 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
4001 /* And the corresponding elements must match. */
4002 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4003 if (rtx_equal_for_thread_p (XVECEXP (x
, i
, j
),
4004 XVECEXP (y
, i
, j
), yinsn
) == 0)
4009 if (rtx_equal_for_thread_p (XEXP (x
, i
), XEXP (y
, i
), yinsn
) == 0)
4015 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
4020 /* These are just backpointers, so they don't matter. */
4027 /* It is believed that rtx's at this level will never
4028 contain anything but integers and other rtx's,
4029 except for within LABEL_REFs and SYMBOL_REFs. */