1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 88, 89, 91-98, 1999 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
22 /* This is the jump-optimization pass of the compiler.
23 It is run two or three times: once before cse, sometimes once after cse,
24 and once after reload (before final).
26 jump_optimize deletes unreachable code and labels that are not used.
27 It also deletes jumps that jump to the following insn,
28 and simplifies jumps around unconditional jumps and jumps
29 to unconditional jumps.
31 Each CODE_LABEL has a count of the times it is used
32 stored in the LABEL_NUSES internal field, and each JUMP_INSN
33 has one label that it refers to stored in the
34 JUMP_LABEL internal field. With this we can detect labels that
35 become unused because of the deletion of all the jumps that
36 formerly used them. The JUMP_LABEL info is sometimes looked
39 Optionally, cross-jumping can be done. Currently it is done
40 only the last time (when after reload and before final).
41 In fact, the code for cross-jumping now assumes that register
42 allocation has been done, since it uses `rtx_renumbered_equal_p'.
44 Jump optimization is done after cse when cse's constant-propagation
45 causes jumps to become unconditional or to be deleted.
47 Unreachable loops are not detected here, because the labels
48 have references and the insns appear reachable from the labels.
49 find_basic_blocks in flow.c finds and deletes such loops.
51 The subroutines delete_insn, redirect_jump, and invert_jump are used
52 from other passes as well. */
59 #include "hard-reg-set.h"
61 #include "insn-config.h"
62 #include "insn-flags.h"
63 #include "insn-attr.h"
71 /* ??? Eventually must record somehow the labels used by jumps
72 from nested functions. */
73 /* Pre-record the next or previous real insn for each label?
74 No, this pass is very fast anyway. */
75 /* Condense consecutive labels?
76 This would make life analysis faster, maybe. */
77 /* Optimize jump y; x: ... y: jumpif... x?
78 Don't know if it is worth bothering with. */
79 /* Optimize two cases of conditional jump to conditional jump?
80 This can never delete any instruction or make anything dead,
81 or even change what is live at any point.
82 So perhaps let combiner do it. */
84 /* Vector indexed by uid.
85 For each CODE_LABEL, index by its uid to get first unconditional jump
86 that jumps to the label.
87 For each JUMP_INSN, index by its uid to get the next unconditional jump
88 that jumps to the same label.
89 Element 0 is the start of a chain of all return insns.
90 (It is safe to use element 0 because insn uid 0 is not used. */
92 static rtx
*jump_chain
;
94 /* Maximum index in jump_chain. */
96 static int max_jump_chain
;
98 /* Set nonzero by jump_optimize if control can fall through
99 to the end of the function. */
102 /* Indicates whether death notes are significant in cross jump analysis.
103 Normally they are not significant, because of A and B jump to C,
104 and R dies in A, it must die in B. But this might not be true after
105 stack register conversion, and we must compare death notes in that
108 static int cross_jump_death_matters
= 0;
110 static int init_label_info
PROTO((rtx
));
111 static void delete_barrier_successors
PROTO((rtx
));
112 static void mark_all_labels
PROTO((rtx
, int));
113 static rtx delete_unreferenced_labels
PROTO((rtx
));
114 static void delete_noop_moves
PROTO((rtx
));
115 static int calculate_can_reach_end
PROTO((rtx
, int, int));
116 static int duplicate_loop_exit_test
PROTO((rtx
));
117 static void find_cross_jump
PROTO((rtx
, rtx
, int, rtx
*, rtx
*));
118 static void do_cross_jump
PROTO((rtx
, rtx
, rtx
));
119 static int jump_back_p
PROTO((rtx
, rtx
));
120 static int tension_vector_labels
PROTO((rtx
, int));
121 static void mark_jump_label
PROTO((rtx
, rtx
, int));
122 static void delete_computation
PROTO((rtx
));
123 static void delete_from_jump_chain
PROTO((rtx
));
124 static int delete_labelref_insn
PROTO((rtx
, rtx
, int));
125 static void mark_modified_reg
PROTO((rtx
, rtx
, void *));
126 static void redirect_tablejump
PROTO((rtx
, rtx
));
127 static void jump_optimize_1
PROTO ((rtx
, int, int, int, int));
128 #if ! defined(HAVE_cc0) && ! defined(HAVE_conditional_arithmetic)
129 static rtx find_insert_position
PROTO((rtx
, rtx
));
131 static int returnjump_p_1
PROTO((rtx
*, void *));
132 static void delete_prior_computation
PROTO((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);
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);
157 /* Delete no-op jumps and optimize jumps to jumps
158 and jumps around jumps.
159 Delete unused labels and unreachable code.
161 If CROSS_JUMP is 1, detect matching code
162 before a jump and its destination and unify them.
163 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
165 If NOOP_MOVES is nonzero, delete no-op move insns.
167 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
168 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
170 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
171 and JUMP_LABEL field for jumping insns.
173 If `optimize' is zero, don't change any code,
174 just determine whether control drops off the end of the function.
175 This case occurs when we have -W and not -O.
176 It works because `delete_insn' checks the value of `optimize'
177 and refrains from actually deleting when that is 0. */
180 jump_optimize_1 (f
, cross_jump
, noop_moves
, after_regscan
, mark_labels_only
)
185 int mark_labels_only
;
187 register rtx insn
, next
;
194 cross_jump_death_matters
= (cross_jump
== 2);
195 max_uid
= init_label_info (f
) + 1;
197 /* If we are performing cross jump optimizations, then initialize
198 tables mapping UIDs to EH regions to avoid incorrect movement
199 of insns from one EH region to another. */
200 if (flag_exceptions
&& cross_jump
)
201 init_insn_eh_region (f
, max_uid
);
203 delete_barrier_successors (f
);
205 /* Leave some extra room for labels and duplicate exit test insns
207 max_jump_chain
= max_uid
* 14 / 10;
208 jump_chain
= (rtx
*) alloca (max_jump_chain
* sizeof (rtx
));
209 bzero ((char *) jump_chain
, max_jump_chain
* sizeof (rtx
));
211 mark_all_labels (f
, cross_jump
);
213 /* Keep track of labels used from static data;
214 they cannot ever be deleted. */
216 for (insn
= forced_labels
; insn
; insn
= XEXP (insn
, 1))
217 LABEL_NUSES (XEXP (insn
, 0))++;
219 check_exception_handler_labels ();
221 /* Keep track of labels used for marking handlers for exception
222 regions; they cannot usually be deleted. */
224 for (insn
= exception_handler_labels
; insn
; insn
= XEXP (insn
, 1))
225 LABEL_NUSES (XEXP (insn
, 0))++;
227 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
228 notes and recompute LABEL_NUSES. */
229 if (mark_labels_only
)
232 exception_optimize ();
234 last_insn
= delete_unreferenced_labels (f
);
238 /* CAN_REACH_END is persistent for each function. Once set it should
239 not be cleared. This is especially true for the case where we
240 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
241 the front-end before compiling each function. */
242 if (calculate_can_reach_end (last_insn
, 1, 0))
245 /* Zero the "deleted" flag of all the "deleted" insns. */
246 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
247 INSN_DELETED_P (insn
) = 0;
249 /* Show that the jump chain is not valid. */
257 /* If we fall through to the epilogue, see if we can insert a RETURN insn
258 in front of it. If the machine allows it at this point (we might be
259 after reload for a leaf routine), it will improve optimization for it
261 insn
= get_last_insn ();
262 while (insn
&& GET_CODE (insn
) == NOTE
)
263 insn
= PREV_INSN (insn
);
265 if (insn
&& GET_CODE (insn
) != BARRIER
)
267 emit_jump_insn (gen_return ());
274 delete_noop_moves (f
);
276 /* If we haven't yet gotten to reload and we have just run regscan,
277 delete any insn that sets a register that isn't used elsewhere.
278 This helps some of the optimizations below by having less insns
279 being jumped around. */
281 if (! reload_completed
&& after_regscan
)
282 for (insn
= f
; insn
; insn
= next
)
284 rtx set
= single_set (insn
);
286 next
= NEXT_INSN (insn
);
288 if (set
&& GET_CODE (SET_DEST (set
)) == REG
289 && REGNO (SET_DEST (set
)) >= FIRST_PSEUDO_REGISTER
290 && REGNO_FIRST_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
291 /* We use regno_last_note_uid so as not to delete the setting
292 of a reg that's used in notes. A subsequent optimization
293 might arrange to use that reg for real. */
294 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
295 && ! side_effects_p (SET_SRC (set
))
296 && ! find_reg_note (insn
, REG_RETVAL
, 0)
297 /* An ADDRESSOF expression can turn into a use of the internal arg
298 pointer, so do not delete the initialization of the internal
299 arg pointer yet. If it is truly dead, flow will delete the
300 initializing insn. */
301 && SET_DEST (set
) != current_function_internal_arg_pointer
)
305 /* Now iterate optimizing jumps until nothing changes over one pass. */
307 old_max_reg
= max_reg_num ();
312 for (insn
= f
; insn
; insn
= next
)
315 rtx temp
, temp1
, temp2
, temp3
, temp4
, temp5
, temp6
;
317 int this_is_simplejump
, this_is_condjump
, reversep
= 0;
318 int this_is_condjump_in_parallel
;
320 next
= NEXT_INSN (insn
);
322 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
323 jump. Try to optimize by duplicating the loop exit test if so.
324 This is only safe immediately after regscan, because it uses
325 the values of regno_first_uid and regno_last_uid. */
326 if (after_regscan
&& GET_CODE (insn
) == NOTE
327 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
328 && (temp1
= next_nonnote_insn (insn
)) != 0
329 && simplejump_p (temp1
))
331 temp
= PREV_INSN (insn
);
332 if (duplicate_loop_exit_test (insn
))
335 next
= NEXT_INSN (temp
);
340 if (GET_CODE (insn
) != JUMP_INSN
)
343 this_is_simplejump
= simplejump_p (insn
);
344 this_is_condjump
= condjump_p (insn
);
345 this_is_condjump_in_parallel
= condjump_in_parallel_p (insn
);
347 /* Tension the labels in dispatch tables. */
349 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
)
350 changed
|= tension_vector_labels (PATTERN (insn
), 0);
351 if (GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
352 changed
|= tension_vector_labels (PATTERN (insn
), 1);
354 /* See if this jump goes to another jump and redirect if so. */
355 nlabel
= follow_jumps (JUMP_LABEL (insn
));
356 if (nlabel
!= JUMP_LABEL (insn
))
357 changed
|= redirect_jump (insn
, nlabel
);
359 /* If a dispatch table always goes to the same place,
360 get rid of it and replace the insn that uses it. */
362 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
363 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
366 rtx pat
= PATTERN (insn
);
367 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
368 int len
= XVECLEN (pat
, diff_vec_p
);
369 rtx dispatch
= prev_real_insn (insn
);
372 for (i
= 0; i
< len
; i
++)
373 if (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)
374 != XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0))
379 && GET_CODE (dispatch
) == JUMP_INSN
380 && JUMP_LABEL (dispatch
) != 0
381 /* Don't mess with a casesi insn.
382 XXX according to the comment before computed_jump_p(),
383 all casesi insns should be a parallel of the jump
384 and a USE of a LABEL_REF. */
385 && ! ((set
= single_set (dispatch
)) != NULL
386 && (GET_CODE (SET_SRC (set
)) == IF_THEN_ELSE
))
387 && next_real_insn (JUMP_LABEL (dispatch
)) == insn
)
389 redirect_tablejump (dispatch
,
390 XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0));
395 /* If a jump references the end of the function, try to turn
396 it into a RETURN insn, possibly a conditional one. */
397 if (JUMP_LABEL (insn
) != 0
398 && (next_active_insn (JUMP_LABEL (insn
)) == 0
399 || GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn
))))
401 changed
|= redirect_jump (insn
, NULL_RTX
);
403 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
405 /* Detect jump to following insn. */
406 if (reallabelprev
== insn
&& this_is_condjump
)
408 next
= next_real_insn (JUMP_LABEL (insn
));
414 /* Detect a conditional jump going to the same place
415 as an immediately following unconditional jump. */
416 else if (this_is_condjump
417 && (temp
= next_active_insn (insn
)) != 0
418 && simplejump_p (temp
)
419 && (next_active_insn (JUMP_LABEL (insn
))
420 == next_active_insn (JUMP_LABEL (temp
))))
422 /* Don't mess up test coverage analysis. */
424 if (flag_test_coverage
&& !reload_completed
)
425 for (temp2
= insn
; temp2
!= temp
; temp2
= NEXT_INSN (temp2
))
426 if (GET_CODE (temp2
) == NOTE
&& NOTE_LINE_NUMBER (temp2
) > 0)
437 /* Detect a conditional jump jumping over an unconditional jump. */
439 else if ((this_is_condjump
|| this_is_condjump_in_parallel
)
440 && ! this_is_simplejump
441 && reallabelprev
!= 0
442 && GET_CODE (reallabelprev
) == JUMP_INSN
443 && prev_active_insn (reallabelprev
) == insn
444 && no_labels_between_p (insn
, reallabelprev
)
445 && simplejump_p (reallabelprev
))
447 /* When we invert the unconditional jump, we will be
448 decrementing the usage count of its old label.
449 Make sure that we don't delete it now because that
450 might cause the following code to be deleted. */
451 rtx prev_uses
= prev_nonnote_insn (reallabelprev
);
452 rtx prev_label
= JUMP_LABEL (insn
);
455 ++LABEL_NUSES (prev_label
);
457 if (invert_jump (insn
, JUMP_LABEL (reallabelprev
)))
459 /* It is very likely that if there are USE insns before
460 this jump, they hold REG_DEAD notes. These REG_DEAD
461 notes are no longer valid due to this optimization,
462 and will cause the life-analysis that following passes
463 (notably delayed-branch scheduling) to think that
464 these registers are dead when they are not.
466 To prevent this trouble, we just remove the USE insns
467 from the insn chain. */
469 while (prev_uses
&& GET_CODE (prev_uses
) == INSN
470 && GET_CODE (PATTERN (prev_uses
)) == USE
)
472 rtx useless
= prev_uses
;
473 prev_uses
= prev_nonnote_insn (prev_uses
);
474 delete_insn (useless
);
477 delete_insn (reallabelprev
);
481 /* We can now safely delete the label if it is unreferenced
482 since the delete_insn above has deleted the BARRIER. */
483 if (prev_label
&& --LABEL_NUSES (prev_label
) == 0)
484 delete_insn (prev_label
);
486 next
= NEXT_INSN (insn
);
489 /* If we have an unconditional jump preceded by a USE, try to put
490 the USE before the target and jump there. This simplifies many
491 of the optimizations below since we don't have to worry about
492 dealing with these USE insns. We only do this if the label
493 being branch to already has the identical USE or if code
494 never falls through to that label. */
496 else if (this_is_simplejump
497 && (temp
= prev_nonnote_insn (insn
)) != 0
498 && GET_CODE (temp
) == INSN
499 && GET_CODE (PATTERN (temp
)) == USE
500 && (temp1
= prev_nonnote_insn (JUMP_LABEL (insn
))) != 0
501 && (GET_CODE (temp1
) == BARRIER
502 || (GET_CODE (temp1
) == INSN
503 && rtx_equal_p (PATTERN (temp
), PATTERN (temp1
))))
504 /* Don't do this optimization if we have a loop containing
505 only the USE instruction, and the loop start label has
506 a usage count of 1. This is because we will redo this
507 optimization everytime through the outer loop, and jump
508 opt will never exit. */
509 && ! ((temp2
= prev_nonnote_insn (temp
)) != 0
510 && temp2
== JUMP_LABEL (insn
)
511 && LABEL_NUSES (temp2
) == 1))
513 if (GET_CODE (temp1
) == BARRIER
)
515 emit_insn_after (PATTERN (temp
), temp1
);
516 temp1
= NEXT_INSN (temp1
);
520 redirect_jump (insn
, get_label_before (temp1
));
521 reallabelprev
= prev_real_insn (temp1
);
523 next
= NEXT_INSN (insn
);
526 /* Simplify if (...) x = a; else x = b; by converting it
527 to x = b; if (...) x = a;
528 if B is sufficiently simple, the test doesn't involve X,
529 and nothing in the test modifies B or X.
531 If we have small register classes, we also can't do this if X
534 If the "x = b;" insn has any REG_NOTES, we don't do this because
535 of the possibility that we are running after CSE and there is a
536 REG_EQUAL note that is only valid if the branch has already been
537 taken. If we move the insn with the REG_EQUAL note, we may
538 fold the comparison to always be false in a later CSE pass.
539 (We could also delete the REG_NOTES when moving the insn, but it
540 seems simpler to not move it.) An exception is that we can move
541 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
542 value is the same as "b".
544 INSN is the branch over the `else' part.
548 TEMP to the jump insn preceding "x = a;"
550 TEMP2 to the insn that sets "x = b;"
551 TEMP3 to the insn that sets "x = a;"
552 TEMP4 to the set of "x = b"; */
554 if (this_is_simplejump
555 && (temp3
= prev_active_insn (insn
)) != 0
556 && GET_CODE (temp3
) == INSN
557 && (temp4
= single_set (temp3
)) != 0
558 && GET_CODE (temp1
= SET_DEST (temp4
)) == REG
559 && (! SMALL_REGISTER_CLASSES
560 || REGNO (temp1
) >= FIRST_PSEUDO_REGISTER
)
561 && (temp2
= next_active_insn (insn
)) != 0
562 && GET_CODE (temp2
) == INSN
563 && (temp4
= single_set (temp2
)) != 0
564 && rtx_equal_p (SET_DEST (temp4
), temp1
)
565 && ! side_effects_p (SET_SRC (temp4
))
566 && ! may_trap_p (SET_SRC (temp4
))
567 && (REG_NOTES (temp2
) == 0
568 || ((REG_NOTE_KIND (REG_NOTES (temp2
)) == REG_EQUAL
569 || REG_NOTE_KIND (REG_NOTES (temp2
)) == REG_EQUIV
)
570 && XEXP (REG_NOTES (temp2
), 1) == 0
571 && rtx_equal_p (XEXP (REG_NOTES (temp2
), 0),
573 && (temp
= prev_active_insn (temp3
)) != 0
574 && condjump_p (temp
) && ! simplejump_p (temp
)
575 /* TEMP must skip over the "x = a;" insn */
576 && prev_real_insn (JUMP_LABEL (temp
)) == insn
577 && no_labels_between_p (insn
, JUMP_LABEL (temp
))
578 /* There must be no other entries to the "x = b;" insn. */
579 && no_labels_between_p (JUMP_LABEL (temp
), temp2
)
580 /* INSN must either branch to the insn after TEMP2 or the insn
581 after TEMP2 must branch to the same place as INSN. */
582 && (reallabelprev
== temp2
583 || ((temp5
= next_active_insn (temp2
)) != 0
584 && simplejump_p (temp5
)
585 && JUMP_LABEL (temp5
) == JUMP_LABEL (insn
))))
587 /* The test expression, X, may be a complicated test with
588 multiple branches. See if we can find all the uses of
589 the label that TEMP branches to without hitting a CALL_INSN
590 or a jump to somewhere else. */
591 rtx target
= JUMP_LABEL (temp
);
592 int nuses
= LABEL_NUSES (target
);
598 /* Set P to the first jump insn that goes around "x = a;". */
599 for (p
= temp
; nuses
&& p
; p
= prev_nonnote_insn (p
))
601 if (GET_CODE (p
) == JUMP_INSN
)
603 if (condjump_p (p
) && ! simplejump_p (p
)
604 && JUMP_LABEL (p
) == target
)
613 else if (GET_CODE (p
) == CALL_INSN
)
618 /* We cannot insert anything between a set of cc and its use
619 so if P uses cc0, we must back up to the previous insn. */
620 q
= prev_nonnote_insn (p
);
621 if (q
&& GET_RTX_CLASS (GET_CODE (q
)) == 'i'
622 && sets_cc0_p (PATTERN (q
)))
629 /* If we found all the uses and there was no data conflict, we
630 can move the assignment unless we can branch into the middle
633 && no_labels_between_p (p
, insn
)
634 && ! reg_referenced_between_p (temp1
, p
, NEXT_INSN (temp3
))
635 && ! reg_set_between_p (temp1
, p
, temp3
)
636 && (GET_CODE (SET_SRC (temp4
)) == CONST_INT
637 || ! modified_between_p (SET_SRC (temp4
), p
, temp2
))
638 /* Verify that registers used by the jump are not clobbered
639 by the instruction being moved. */
640 && ! regs_set_between_p (PATTERN (temp
),
644 emit_insn_after_with_line_notes (PATTERN (temp2
), p
, temp2
);
647 /* Set NEXT to an insn that we know won't go away. */
648 next
= next_active_insn (insn
);
650 /* Delete the jump around the set. Note that we must do
651 this before we redirect the test jumps so that it won't
652 delete the code immediately following the assignment
653 we moved (which might be a jump). */
657 /* We either have two consecutive labels or a jump to
658 a jump, so adjust all the JUMP_INSNs to branch to where
660 for (p
= NEXT_INSN (p
); p
!= next
; p
= NEXT_INSN (p
))
661 if (GET_CODE (p
) == JUMP_INSN
)
662 redirect_jump (p
, target
);
665 next
= NEXT_INSN (insn
);
670 /* Simplify if (...) { x = a; goto l; } x = b; by converting it
671 to x = a; if (...) goto l; x = b;
672 if A is sufficiently simple, the test doesn't involve X,
673 and nothing in the test modifies A or X.
675 If we have small register classes, we also can't do this if X
678 If the "x = a;" insn has any REG_NOTES, we don't do this because
679 of the possibility that we are running after CSE and there is a
680 REG_EQUAL note that is only valid if the branch has already been
681 taken. If we move the insn with the REG_EQUAL note, we may
682 fold the comparison to always be false in a later CSE pass.
683 (We could also delete the REG_NOTES when moving the insn, but it
684 seems simpler to not move it.) An exception is that we can move
685 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
686 value is the same as "a".
692 TEMP to the jump insn preceding "x = a;"
694 TEMP2 to the insn that sets "x = b;"
695 TEMP3 to the insn that sets "x = a;"
696 TEMP4 to the set of "x = a"; */
698 if (this_is_simplejump
699 && (temp2
= next_active_insn (insn
)) != 0
700 && GET_CODE (temp2
) == INSN
701 && (temp4
= single_set (temp2
)) != 0
702 && GET_CODE (temp1
= SET_DEST (temp4
)) == REG
703 && (! SMALL_REGISTER_CLASSES
704 || REGNO (temp1
) >= FIRST_PSEUDO_REGISTER
)
705 && (temp3
= prev_active_insn (insn
)) != 0
706 && GET_CODE (temp3
) == INSN
707 && (temp4
= single_set (temp3
)) != 0
708 && rtx_equal_p (SET_DEST (temp4
), temp1
)
709 && ! side_effects_p (SET_SRC (temp4
))
710 && ! may_trap_p (SET_SRC (temp4
))
711 && (REG_NOTES (temp3
) == 0
712 || ((REG_NOTE_KIND (REG_NOTES (temp3
)) == REG_EQUAL
713 || REG_NOTE_KIND (REG_NOTES (temp3
)) == REG_EQUIV
)
714 && XEXP (REG_NOTES (temp3
), 1) == 0
715 && rtx_equal_p (XEXP (REG_NOTES (temp3
), 0),
717 && (temp
= prev_active_insn (temp3
)) != 0
718 && condjump_p (temp
) && ! simplejump_p (temp
)
719 /* TEMP must skip over the "x = a;" insn */
720 && prev_real_insn (JUMP_LABEL (temp
)) == insn
721 && no_labels_between_p (temp
, insn
))
723 rtx prev_label
= JUMP_LABEL (temp
);
724 rtx insert_after
= prev_nonnote_insn (temp
);
727 /* We cannot insert anything between a set of cc and its use. */
728 if (insert_after
&& GET_RTX_CLASS (GET_CODE (insert_after
)) == 'i'
729 && sets_cc0_p (PATTERN (insert_after
)))
730 insert_after
= prev_nonnote_insn (insert_after
);
732 ++LABEL_NUSES (prev_label
);
735 && no_labels_between_p (insert_after
, temp
)
736 && ! reg_referenced_between_p (temp1
, insert_after
, temp3
)
737 && ! reg_referenced_between_p (temp1
, temp3
,
739 && ! reg_set_between_p (temp1
, insert_after
, temp
)
740 && ! modified_between_p (SET_SRC (temp4
), insert_after
, temp
)
741 /* Verify that registers used by the jump are not clobbered
742 by the instruction being moved. */
743 && ! regs_set_between_p (PATTERN (temp
),
746 && invert_jump (temp
, JUMP_LABEL (insn
)))
748 emit_insn_after_with_line_notes (PATTERN (temp3
),
749 insert_after
, temp3
);
752 /* Set NEXT to an insn that we know won't go away. */
756 if (prev_label
&& --LABEL_NUSES (prev_label
) == 0)
757 delete_insn (prev_label
);
762 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
764 /* If we have if (...) x = exp; and branches are expensive,
765 EXP is a single insn, does not have any side effects, cannot
766 trap, and is not too costly, convert this to
767 t = exp; if (...) x = t;
769 Don't do this when we have CC0 because it is unlikely to help
770 and we'd need to worry about where to place the new insn and
771 the potential for conflicts. We also can't do this when we have
772 notes on the insn for the same reason as above.
774 If we have conditional arithmetic, this will make this
775 harder to optimize later and isn't needed, so don't do it
780 TEMP to the "x = exp;" insn.
781 TEMP1 to the single set in the "x = exp;" insn.
784 if (! reload_completed
785 && this_is_condjump
&& ! this_is_simplejump
787 && (temp
= next_nonnote_insn (insn
)) != 0
788 && GET_CODE (temp
) == INSN
789 && REG_NOTES (temp
) == 0
790 && (reallabelprev
== temp
791 || ((temp2
= next_active_insn (temp
)) != 0
792 && simplejump_p (temp2
)
793 && JUMP_LABEL (temp2
) == JUMP_LABEL (insn
)))
794 && (temp1
= single_set (temp
)) != 0
795 && (temp2
= SET_DEST (temp1
), GET_CODE (temp2
) == REG
)
796 && (! SMALL_REGISTER_CLASSES
797 || REGNO (temp2
) >= FIRST_PSEUDO_REGISTER
)
798 && GET_CODE (SET_SRC (temp1
)) != REG
799 && GET_CODE (SET_SRC (temp1
)) != SUBREG
800 && GET_CODE (SET_SRC (temp1
)) != CONST_INT
801 && ! side_effects_p (SET_SRC (temp1
))
802 && ! may_trap_p (SET_SRC (temp1
))
803 && rtx_cost (SET_SRC (temp1
), SET
) < 10)
805 rtx
new = gen_reg_rtx (GET_MODE (temp2
));
807 if ((temp3
= find_insert_position (insn
, temp
))
808 && validate_change (temp
, &SET_DEST (temp1
), new, 0))
810 next
= emit_insn_after (gen_move_insn (temp2
, new), insn
);
811 emit_insn_after_with_line_notes (PATTERN (temp
),
812 PREV_INSN (temp3
), temp
);
814 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
818 reg_scan_update (temp3
, NEXT_INSN (next
), old_max_reg
);
819 old_max_reg
= max_reg_num ();
824 /* Similarly, if it takes two insns to compute EXP but they
825 have the same destination. Here TEMP3 will be the second
826 insn and TEMP4 the SET from that insn. */
828 if (! reload_completed
829 && this_is_condjump
&& ! this_is_simplejump
831 && (temp
= next_nonnote_insn (insn
)) != 0
832 && GET_CODE (temp
) == INSN
833 && REG_NOTES (temp
) == 0
834 && (temp3
= next_nonnote_insn (temp
)) != 0
835 && GET_CODE (temp3
) == INSN
836 && REG_NOTES (temp3
) == 0
837 && (reallabelprev
== temp3
838 || ((temp2
= next_active_insn (temp3
)) != 0
839 && simplejump_p (temp2
)
840 && JUMP_LABEL (temp2
) == JUMP_LABEL (insn
)))
841 && (temp1
= single_set (temp
)) != 0
842 && (temp2
= SET_DEST (temp1
), GET_CODE (temp2
) == REG
)
843 && GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
844 && (! SMALL_REGISTER_CLASSES
845 || REGNO (temp2
) >= FIRST_PSEUDO_REGISTER
)
846 && ! side_effects_p (SET_SRC (temp1
))
847 && ! may_trap_p (SET_SRC (temp1
))
848 && rtx_cost (SET_SRC (temp1
), SET
) < 10
849 && (temp4
= single_set (temp3
)) != 0
850 && rtx_equal_p (SET_DEST (temp4
), temp2
)
851 && ! side_effects_p (SET_SRC (temp4
))
852 && ! may_trap_p (SET_SRC (temp4
))
853 && rtx_cost (SET_SRC (temp4
), SET
) < 10)
855 rtx
new = gen_reg_rtx (GET_MODE (temp2
));
857 if ((temp5
= find_insert_position (insn
, temp
))
858 && (temp6
= find_insert_position (insn
, temp3
))
859 && validate_change (temp
, &SET_DEST (temp1
), new, 0))
861 /* Use the earliest of temp5 and temp6. */
864 next
= emit_insn_after (gen_move_insn (temp2
, new), insn
);
865 emit_insn_after_with_line_notes (PATTERN (temp
),
866 PREV_INSN (temp6
), temp
);
867 emit_insn_after_with_line_notes
868 (replace_rtx (PATTERN (temp3
), temp2
, new),
869 PREV_INSN (temp6
), temp3
);
872 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
876 reg_scan_update (temp6
, NEXT_INSN (next
), old_max_reg
);
877 old_max_reg
= max_reg_num ();
882 /* Finally, handle the case where two insns are used to
883 compute EXP but a temporary register is used. Here we must
884 ensure that the temporary register is not used anywhere else. */
886 if (! reload_completed
888 && this_is_condjump
&& ! this_is_simplejump
890 && (temp
= next_nonnote_insn (insn
)) != 0
891 && GET_CODE (temp
) == INSN
892 && REG_NOTES (temp
) == 0
893 && (temp3
= next_nonnote_insn (temp
)) != 0
894 && GET_CODE (temp3
) == INSN
895 && REG_NOTES (temp3
) == 0
896 && (reallabelprev
== temp3
897 || ((temp2
= next_active_insn (temp3
)) != 0
898 && simplejump_p (temp2
)
899 && JUMP_LABEL (temp2
) == JUMP_LABEL (insn
)))
900 && (temp1
= single_set (temp
)) != 0
901 && (temp5
= SET_DEST (temp1
),
902 (GET_CODE (temp5
) == REG
903 || (GET_CODE (temp5
) == SUBREG
904 && (temp5
= SUBREG_REG (temp5
),
905 GET_CODE (temp5
) == REG
))))
906 && REGNO (temp5
) >= FIRST_PSEUDO_REGISTER
907 && REGNO_FIRST_UID (REGNO (temp5
)) == INSN_UID (temp
)
908 && REGNO_LAST_UID (REGNO (temp5
)) == INSN_UID (temp3
)
909 && ! side_effects_p (SET_SRC (temp1
))
910 && ! may_trap_p (SET_SRC (temp1
))
911 && rtx_cost (SET_SRC (temp1
), SET
) < 10
912 && (temp4
= single_set (temp3
)) != 0
913 && (temp2
= SET_DEST (temp4
), GET_CODE (temp2
) == REG
)
914 && GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
915 && (! SMALL_REGISTER_CLASSES
916 || REGNO (temp2
) >= FIRST_PSEUDO_REGISTER
)
917 && rtx_equal_p (SET_DEST (temp4
), temp2
)
918 && ! side_effects_p (SET_SRC (temp4
))
919 && ! may_trap_p (SET_SRC (temp4
))
920 && rtx_cost (SET_SRC (temp4
), SET
) < 10)
922 rtx
new = gen_reg_rtx (GET_MODE (temp2
));
924 if ((temp5
= find_insert_position (insn
, temp
))
925 && (temp6
= find_insert_position (insn
, temp3
))
926 && validate_change (temp3
, &SET_DEST (temp4
), new, 0))
928 /* Use the earliest of temp5 and temp6. */
931 next
= emit_insn_after (gen_move_insn (temp2
, new), insn
);
932 emit_insn_after_with_line_notes (PATTERN (temp
),
933 PREV_INSN (temp6
), temp
);
934 emit_insn_after_with_line_notes (PATTERN (temp3
),
935 PREV_INSN (temp6
), temp3
);
938 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
942 reg_scan_update (temp6
, NEXT_INSN (next
), old_max_reg
);
943 old_max_reg
= max_reg_num ();
947 #endif /* HAVE_cc0 */
949 #ifdef HAVE_conditional_arithmetic
950 /* ??? This is disabled in genconfig, as this simple-minded
951 transformation can incredibly lengthen register lifetimes.
953 Consider this example from cexp.c's yyparse:
956 (if_then_else (ne (reg:DI 149) (const_int 0 [0x0]))
957 (label_ref 248) (pc)))
958 237 (set (reg/i:DI 0 $0) (const_int 1 [0x1]))
959 239 (set (pc) (label_ref 2382))
960 248 (code_label ("yybackup"))
962 This will be transformed to:
964 237 (set (reg/i:DI 0 $0)
965 (if_then_else:DI (eq (reg:DI 149) (const_int 0 [0x0]))
966 (const_int 1 [0x1]) (reg/i:DI 0 $0)))
968 (if_then_else (eq (reg:DI 149) (const_int 0 [0x0]))
969 (label_ref 2382) (pc)))
971 which, from this narrow viewpoint looks fine. Except that
972 between this and 3 other ocurrences of the same pattern, $0
973 is now live for basically the entire function, and we'll
974 get an abort in caller_save.
976 Any replacement for this code should recall that a set of
977 a register that is not live need not, and indeed should not,
978 be conditionalized. Either that, or delay the transformation
979 until after register allocation. */
981 /* See if this is a conditional jump around a small number of
982 instructions that we can conditionalize. Don't do this before
983 the initial CSE pass or after reload.
985 We reject any insns that have side effects or may trap.
986 Strictly speaking, this is not needed since the machine may
987 support conditionalizing these too, but we won't deal with that
988 now. Specifically, this means that we can't conditionalize a
989 CALL_INSN, which some machines, such as the ARC, can do, but
990 this is a very minor optimization. */
991 if (this_is_condjump
&& ! this_is_simplejump
992 && cse_not_expected
&& optimize
> 0 && ! reload_completed
994 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (insn
)), 0),
997 rtx ourcond
= XEXP (SET_SRC (PATTERN (insn
)), 0);
999 char *storage
= (char *) oballoc (0);
1000 int last_insn
= 0, failed
= 0;
1001 rtx changed_jump
= 0;
1003 ourcond
= gen_rtx (reverse_condition (GET_CODE (ourcond
)),
1004 VOIDmode
, XEXP (ourcond
, 0),
1007 /* Scan forward BRANCH_COST real insns looking for the JUMP_LABEL
1008 of this insn. We see if we think we can conditionalize the
1009 insns we pass. For now, we only deal with insns that have
1010 one SET. We stop after an insn that modifies anything in
1011 OURCOND, if we have too many insns, or if we have an insn
1012 with a side effect or that may trip. Note that we will
1013 be modifying any unconditional jumps we encounter to be
1014 conditional; this will have the effect of also doing this
1015 optimization on the "else" the next time around. */
1016 for (temp1
= NEXT_INSN (insn
);
1017 num_insns
<= BRANCH_COST
&& ! failed
&& temp1
!= 0
1018 && GET_CODE (temp1
) != CODE_LABEL
;
1019 temp1
= NEXT_INSN (temp1
))
1021 /* Ignore everything but an active insn. */
1022 if (GET_RTX_CLASS (GET_CODE (temp1
)) != 'i'
1023 || GET_CODE (PATTERN (temp1
)) == USE
1024 || GET_CODE (PATTERN (temp1
)) == CLOBBER
)
1027 /* If this was an unconditional jump, record it since we'll
1028 need to remove the BARRIER if we succeed. We can only
1029 have one such jump since there must be a label after
1030 the BARRIER and it's either ours, in which case it's the
1031 only one or some other, in which case we'd fail.
1032 Likewise if it's a CALL_INSN followed by a BARRIER. */
1034 if (simplejump_p (temp1
)
1035 || (GET_CODE (temp1
) == CALL_INSN
1036 && NEXT_INSN (temp1
) != 0
1037 && GET_CODE (NEXT_INSN (temp1
)) == BARRIER
))
1039 if (changed_jump
== 0)
1040 changed_jump
= temp1
;
1043 = gen_rtx_INSN_LIST (VOIDmode
, temp1
, changed_jump
);
1046 /* See if we are allowed another insn and if this insn
1047 if one we think we may be able to handle. */
1048 if (++num_insns
> BRANCH_COST
1050 || (((temp2
= single_set (temp1
)) == 0
1051 || side_effects_p (SET_SRC (temp2
))
1052 || may_trap_p (SET_SRC (temp2
)))
1053 && GET_CODE (temp1
) != CALL_INSN
))
1055 else if (temp2
!= 0)
1056 validate_change (temp1
, &SET_SRC (temp2
),
1057 gen_rtx_IF_THEN_ELSE
1058 (GET_MODE (SET_DEST (temp2
)),
1060 SET_SRC (temp2
), SET_DEST (temp2
)),
1064 /* This is a CALL_INSN that doesn't have a SET. */
1065 rtx
*call_loc
= &PATTERN (temp1
);
1067 if (GET_CODE (*call_loc
) == PARALLEL
)
1068 call_loc
= &XVECEXP (*call_loc
, 0, 0);
1070 validate_change (temp1
, call_loc
,
1071 gen_rtx_IF_THEN_ELSE
1072 (VOIDmode
, copy_rtx (ourcond
),
1073 *call_loc
, const0_rtx
),
1078 if (modified_in_p (ourcond
, temp1
))
1082 /* If we've reached our jump label, haven't failed, and all
1083 the changes above are valid, we can delete this jump
1084 insn. Also remove a BARRIER after any jump that used
1085 to be unconditional and remove any REG_EQUAL or REG_EQUIV
1086 that might have previously been present on insns we
1087 made conditional. */
1088 if (temp1
== JUMP_LABEL (insn
) && ! failed
1089 && apply_change_group ())
1091 for (temp1
= NEXT_INSN (insn
); temp1
!= JUMP_LABEL (insn
);
1092 temp1
= NEXT_INSN (temp1
))
1093 if (GET_RTX_CLASS (GET_CODE (temp1
)) == 'i')
1094 for (temp2
= REG_NOTES (temp1
); temp2
!= 0;
1095 temp2
= XEXP (temp2
, 1))
1096 if (REG_NOTE_KIND (temp2
) == REG_EQUAL
1097 || REG_NOTE_KIND (temp2
) == REG_EQUIV
)
1098 remove_note (temp1
, temp2
);
1100 if (changed_jump
!= 0)
1102 while (GET_CODE (changed_jump
) == INSN_LIST
)
1104 delete_barrier (NEXT_INSN (XEXP (changed_jump
, 0)));
1105 changed_jump
= XEXP (changed_jump
, 1);
1108 delete_barrier (NEXT_INSN (changed_jump
));
1123 /* Try to use a conditional move (if the target has them), or a
1124 store-flag insn. If the target has conditional arithmetic as
1125 well as conditional move, the above code will have done something.
1126 Note that we prefer the above code since it is more general: the
1127 code below can make changes that require work to undo.
1129 The general case here is:
1131 1) x = a; if (...) x = b; and
1134 If the jump would be faster, the machine should not have defined
1135 the movcc or scc insns!. These cases are often made by the
1136 previous optimization.
1138 The second case is treated as x = x; if (...) x = b;.
1140 INSN here is the jump around the store. We set:
1142 TEMP to the "x op= b;" insn.
1145 TEMP3 to A (X in the second case).
1146 TEMP4 to the condition being tested.
1147 TEMP5 to the earliest insn used to find the condition.
1148 TEMP6 to the SET of TEMP. */
1150 if (/* We can't do this after reload has completed. */
1152 #ifdef HAVE_conditional_arithmetic
1153 /* Defer this until after CSE so the above code gets the
1154 first crack at it. */
1157 && this_is_condjump
&& ! this_is_simplejump
1158 /* Set TEMP to the "x = b;" insn. */
1159 && (temp
= next_nonnote_insn (insn
)) != 0
1160 && GET_CODE (temp
) == INSN
1161 && (temp6
= single_set (temp
)) != NULL_RTX
1162 && GET_CODE (temp1
= SET_DEST (temp6
)) == REG
1163 && (! SMALL_REGISTER_CLASSES
1164 || REGNO (temp1
) >= FIRST_PSEUDO_REGISTER
)
1165 && ! side_effects_p (temp2
= SET_SRC (temp6
))
1166 && ! may_trap_p (temp2
)
1167 /* Allow either form, but prefer the former if both apply.
1168 There is no point in using the old value of TEMP1 if
1169 it is a register, since cse will alias them. It can
1170 lose if the old value were a hard register since CSE
1171 won't replace hard registers. Avoid using TEMP3 if
1172 small register classes and it is a hard register. */
1173 && (((temp3
= reg_set_last (temp1
, insn
)) != 0
1174 && ! (SMALL_REGISTER_CLASSES
&& GET_CODE (temp3
) == REG
1175 && REGNO (temp3
) < FIRST_PSEUDO_REGISTER
))
1176 /* Make the latter case look like x = x; if (...) x = b; */
1177 || (temp3
= temp1
, 1))
1178 /* INSN must either branch to the insn after TEMP or the insn
1179 after TEMP must branch to the same place as INSN. */
1180 && (reallabelprev
== temp
1181 || ((temp4
= next_active_insn (temp
)) != 0
1182 && simplejump_p (temp4
)
1183 && JUMP_LABEL (temp4
) == JUMP_LABEL (insn
)))
1184 && (temp4
= get_condition (insn
, &temp5
)) != 0
1185 /* We must be comparing objects whose modes imply the size.
1186 We could handle BLKmode if (1) emit_store_flag could
1187 and (2) we could find the size reliably. */
1188 && GET_MODE (XEXP (temp4
, 0)) != BLKmode
1189 /* Even if branches are cheap, the store_flag optimization
1190 can win when the operation to be performed can be
1191 expressed directly. */
1193 /* If the previous insn sets CC0 and something else, we can't
1194 do this since we are going to delete that insn. */
1196 && ! ((temp6
= prev_nonnote_insn (insn
)) != 0
1197 && GET_CODE (temp6
) == INSN
1198 && (sets_cc0_p (PATTERN (temp6
)) == -1
1199 || (sets_cc0_p (PATTERN (temp6
)) == 1
1200 && FIND_REG_INC_NOTE (temp6
, NULL_RTX
))))
1204 #ifdef HAVE_conditional_move
1205 /* First try a conditional move. */
1207 enum rtx_code code
= GET_CODE (temp4
);
1209 rtx cond0
, cond1
, aval
, bval
;
1210 rtx target
, new_insn
;
1212 /* Copy the compared variables into cond0 and cond1, so that
1213 any side effects performed in or after the old comparison,
1214 will not affect our compare which will come later. */
1215 /* ??? Is it possible to just use the comparison in the jump
1216 insn? After all, we're going to delete it. We'd have
1217 to modify emit_conditional_move to take a comparison rtx
1218 instead or write a new function. */
1219 cond0
= gen_reg_rtx (GET_MODE (XEXP (temp4
, 0)));
1220 /* We want the target to be able to simplify comparisons with
1221 zero (and maybe other constants as well), so don't create
1222 pseudos for them. There's no need to either. */
1223 if (GET_CODE (XEXP (temp4
, 1)) == CONST_INT
1224 || GET_CODE (XEXP (temp4
, 1)) == CONST_DOUBLE
)
1225 cond1
= XEXP (temp4
, 1);
1227 cond1
= gen_reg_rtx (GET_MODE (XEXP (temp4
, 1)));
1229 /* Careful about copying these values -- an IOR or what may
1230 need to do other things, like clobber flags. */
1231 /* ??? Assume for the moment that AVAL is ok. */
1236 /* We're dealing with a single_set insn with no side effects
1237 on SET_SRC. We do need to be reasonably certain that if
1238 we need to force BVAL into a register that we won't
1239 clobber the flags -- general_operand should suffice. */
1240 if (general_operand (temp2
, GET_MODE (var
)))
1244 bval
= gen_reg_rtx (GET_MODE (var
));
1245 new_insn
= copy_rtx (temp
);
1246 temp6
= single_set (new_insn
);
1247 SET_DEST (temp6
) = bval
;
1248 emit_insn (PATTERN (new_insn
));
1251 target
= emit_conditional_move (var
, code
,
1252 cond0
, cond1
, VOIDmode
,
1253 aval
, bval
, GET_MODE (var
),
1254 (code
== LTU
|| code
== GEU
1255 || code
== LEU
|| code
== GTU
));
1259 rtx seq1
, seq2
, last
;
1262 /* Save the conditional move sequence but don't emit it
1263 yet. On some machines, like the alpha, it is possible
1264 that temp5 == insn, so next generate the sequence that
1265 saves the compared values and then emit both
1266 sequences ensuring seq1 occurs before seq2. */
1267 seq2
= get_insns ();
1270 /* "Now that we can't fail..." Famous last words.
1271 Generate the copy insns that preserve the compared
1274 emit_move_insn (cond0
, XEXP (temp4
, 0));
1275 if (cond1
!= XEXP (temp4
, 1))
1276 emit_move_insn (cond1
, XEXP (temp4
, 1));
1277 seq1
= get_insns ();
1280 /* Validate the sequence -- this may be some weird
1281 bit-extract-and-test instruction for which there
1282 exists no complimentary bit-extract insn. */
1284 for (last
= seq1
; last
; last
= NEXT_INSN (last
))
1285 if (recog_memoized (last
) < 0)
1293 emit_insns_before (seq1
, temp5
);
1295 /* Insert conditional move after insn, to be sure
1296 that the jump and a possible compare won't be
1298 last
= emit_insns_after (seq2
, insn
);
1300 /* ??? We can also delete the insn that sets X to A.
1301 Flow will do it too though. */
1303 next
= NEXT_INSN (insn
);
1308 reg_scan_update (seq1
, NEXT_INSN (last
),
1310 old_max_reg
= max_reg_num ();
1322 /* That didn't work, try a store-flag insn.
1324 We further divide the cases into:
1326 1) x = a; if (...) x = b; and either A or B is zero,
1327 2) if (...) x = 0; and jumps are expensive,
1328 3) x = a; if (...) x = b; and A and B are constants where all
1329 the set bits in A are also set in B and jumps are expensive,
1330 4) x = a; if (...) x = b; and A and B non-zero, and jumps are
1332 5) if (...) x = b; if jumps are even more expensive. */
1334 if (GET_MODE_CLASS (GET_MODE (temp1
)) == MODE_INT
1335 && ((GET_CODE (temp3
) == CONST_INT
)
1336 /* Make the latter case look like
1337 x = x; if (...) x = 0; */
1340 && temp2
== const0_rtx
)
1341 || BRANCH_COST
>= 3)))
1342 /* If B is zero, OK; if A is zero, can only do (1) if we
1343 can reverse the condition. See if (3) applies possibly
1344 by reversing the condition. Prefer reversing to (4) when
1345 branches are very expensive. */
1346 && (((BRANCH_COST
>= 2
1347 || STORE_FLAG_VALUE
== -1
1348 || (STORE_FLAG_VALUE
== 1
1349 /* Check that the mask is a power of two,
1350 so that it can probably be generated
1352 && GET_CODE (temp3
) == CONST_INT
1353 && exact_log2 (INTVAL (temp3
)) >= 0))
1354 && (reversep
= 0, temp2
== const0_rtx
))
1355 || ((BRANCH_COST
>= 2
1356 || STORE_FLAG_VALUE
== -1
1357 || (STORE_FLAG_VALUE
== 1
1358 && GET_CODE (temp2
) == CONST_INT
1359 && exact_log2 (INTVAL (temp2
)) >= 0))
1360 && temp3
== const0_rtx
1361 && (reversep
= can_reverse_comparison_p (temp4
, insn
)))
1362 || (BRANCH_COST
>= 2
1363 && GET_CODE (temp2
) == CONST_INT
1364 && GET_CODE (temp3
) == CONST_INT
1365 && ((INTVAL (temp2
) & INTVAL (temp3
)) == INTVAL (temp2
)
1366 || ((INTVAL (temp2
) & INTVAL (temp3
)) == INTVAL (temp3
)
1367 && (reversep
= can_reverse_comparison_p (temp4
,
1369 || BRANCH_COST
>= 3)
1372 enum rtx_code code
= GET_CODE (temp4
);
1373 rtx uval
, cval
, var
= temp1
;
1377 /* If necessary, reverse the condition. */
1379 code
= reverse_condition (code
), uval
= temp2
, cval
= temp3
;
1381 uval
= temp3
, cval
= temp2
;
1383 /* If CVAL is non-zero, normalize to -1. Otherwise, if UVAL
1384 is the constant 1, it is best to just compute the result
1385 directly. If UVAL is constant and STORE_FLAG_VALUE
1386 includes all of its bits, it is best to compute the flag
1387 value unnormalized and `and' it with UVAL. Otherwise,
1388 normalize to -1 and `and' with UVAL. */
1389 normalizep
= (cval
!= const0_rtx
? -1
1390 : (uval
== const1_rtx
? 1
1391 : (GET_CODE (uval
) == CONST_INT
1392 && (INTVAL (uval
) & ~STORE_FLAG_VALUE
) == 0)
1395 /* We will be putting the store-flag insn immediately in
1396 front of the comparison that was originally being done,
1397 so we know all the variables in TEMP4 will be valid.
1398 However, this might be in front of the assignment of
1399 A to VAR. If it is, it would clobber the store-flag
1400 we will be emitting.
1402 Therefore, emit into a temporary which will be copied to
1403 VAR immediately after TEMP. */
1406 target
= emit_store_flag (gen_reg_rtx (GET_MODE (var
)), code
,
1407 XEXP (temp4
, 0), XEXP (temp4
, 1),
1409 (code
== LTU
|| code
== LEU
1410 || code
== GEU
|| code
== GTU
),
1420 /* Put the store-flag insns in front of the first insn
1421 used to compute the condition to ensure that we
1422 use the same values of them as the current
1423 comparison. However, the remainder of the insns we
1424 generate will be placed directly in front of the
1425 jump insn, in case any of the pseudos we use
1426 are modified earlier. */
1428 emit_insns_before (seq
, temp5
);
1432 /* Both CVAL and UVAL are non-zero. */
1433 if (cval
!= const0_rtx
&& uval
!= const0_rtx
)
1437 tem1
= expand_and (uval
, target
, NULL_RTX
);
1438 if (GET_CODE (cval
) == CONST_INT
1439 && GET_CODE (uval
) == CONST_INT
1440 && (INTVAL (cval
) & INTVAL (uval
)) == INTVAL (cval
))
1444 tem2
= expand_unop (GET_MODE (var
), one_cmpl_optab
,
1445 target
, NULL_RTX
, 0);
1446 tem2
= expand_and (cval
, tem2
,
1447 (GET_CODE (tem2
) == REG
1451 /* If we usually make new pseudos, do so here. This
1452 turns out to help machines that have conditional
1454 /* ??? Conditional moves have already been handled.
1455 This may be obsolete. */
1457 if (flag_expensive_optimizations
)
1460 target
= expand_binop (GET_MODE (var
), ior_optab
,
1464 else if (normalizep
!= 1)
1466 /* We know that either CVAL or UVAL is zero. If
1467 UVAL is zero, negate TARGET and `and' with CVAL.
1468 Otherwise, `and' with UVAL. */
1469 if (uval
== const0_rtx
)
1471 target
= expand_unop (GET_MODE (var
), one_cmpl_optab
,
1472 target
, NULL_RTX
, 0);
1476 target
= expand_and (uval
, target
,
1477 (GET_CODE (target
) == REG
1478 && ! preserve_subexpressions_p ()
1479 ? target
: NULL_RTX
));
1482 emit_move_insn (var
, target
);
1486 /* If INSN uses CC0, we must not separate it from the
1487 insn that sets cc0. */
1488 if (reg_mentioned_p (cc0_rtx
, PATTERN (before
)))
1489 before
= prev_nonnote_insn (before
);
1491 emit_insns_before (seq
, before
);
1494 next
= NEXT_INSN (insn
);
1499 reg_scan_update (seq
, NEXT_INSN (next
), old_max_reg
);
1500 old_max_reg
= max_reg_num ();
1511 /* If branches are expensive, convert
1512 if (foo) bar++; to bar += (foo != 0);
1513 and similarly for "bar--;"
1515 INSN is the conditional branch around the arithmetic. We set:
1517 TEMP is the arithmetic insn.
1518 TEMP1 is the SET doing the arithmetic.
1519 TEMP2 is the operand being incremented or decremented.
1520 TEMP3 to the condition being tested.
1521 TEMP4 to the earliest insn used to find the condition. */
1523 if ((BRANCH_COST
>= 2
1531 && ! reload_completed
1532 && this_is_condjump
&& ! this_is_simplejump
1533 && (temp
= next_nonnote_insn (insn
)) != 0
1534 && (temp1
= single_set (temp
)) != 0
1535 && (temp2
= SET_DEST (temp1
),
1536 GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
)
1537 && GET_CODE (SET_SRC (temp1
)) == PLUS
1538 && (XEXP (SET_SRC (temp1
), 1) == const1_rtx
1539 || XEXP (SET_SRC (temp1
), 1) == constm1_rtx
)
1540 && rtx_equal_p (temp2
, XEXP (SET_SRC (temp1
), 0))
1541 && ! side_effects_p (temp2
)
1542 && ! may_trap_p (temp2
)
1543 /* INSN must either branch to the insn after TEMP or the insn
1544 after TEMP must branch to the same place as INSN. */
1545 && (reallabelprev
== temp
1546 || ((temp3
= next_active_insn (temp
)) != 0
1547 && simplejump_p (temp3
)
1548 && JUMP_LABEL (temp3
) == JUMP_LABEL (insn
)))
1549 && (temp3
= get_condition (insn
, &temp4
)) != 0
1550 /* We must be comparing objects whose modes imply the size.
1551 We could handle BLKmode if (1) emit_store_flag could
1552 and (2) we could find the size reliably. */
1553 && GET_MODE (XEXP (temp3
, 0)) != BLKmode
1554 && can_reverse_comparison_p (temp3
, insn
))
1556 rtx temp6
, target
= 0, seq
, init_insn
= 0, init
= temp2
;
1557 enum rtx_code code
= reverse_condition (GET_CODE (temp3
));
1561 /* It must be the case that TEMP2 is not modified in the range
1562 [TEMP4, INSN). The one exception we make is if the insn
1563 before INSN sets TEMP2 to something which is also unchanged
1564 in that range. In that case, we can move the initialization
1565 into our sequence. */
1567 if ((temp5
= prev_active_insn (insn
)) != 0
1568 && no_labels_between_p (temp5
, insn
)
1569 && GET_CODE (temp5
) == INSN
1570 && (temp6
= single_set (temp5
)) != 0
1571 && rtx_equal_p (temp2
, SET_DEST (temp6
))
1572 && (CONSTANT_P (SET_SRC (temp6
))
1573 || GET_CODE (SET_SRC (temp6
)) == REG
1574 || GET_CODE (SET_SRC (temp6
)) == SUBREG
))
1576 emit_insn (PATTERN (temp5
));
1578 init
= SET_SRC (temp6
);
1581 if (CONSTANT_P (init
)
1582 || ! reg_set_between_p (init
, PREV_INSN (temp4
), insn
))
1583 target
= emit_store_flag (gen_reg_rtx (GET_MODE (temp2
)), code
,
1584 XEXP (temp3
, 0), XEXP (temp3
, 1),
1586 (code
== LTU
|| code
== LEU
1587 || code
== GTU
|| code
== GEU
), 1);
1589 /* If we can do the store-flag, do the addition or
1593 target
= expand_binop (GET_MODE (temp2
),
1594 (XEXP (SET_SRC (temp1
), 1) == const1_rtx
1595 ? add_optab
: sub_optab
),
1596 temp2
, target
, temp2
, 0, OPTAB_WIDEN
);
1600 /* Put the result back in temp2 in case it isn't already.
1601 Then replace the jump, possible a CC0-setting insn in
1602 front of the jump, and TEMP, with the sequence we have
1605 if (target
!= temp2
)
1606 emit_move_insn (temp2
, target
);
1611 emit_insns_before (seq
, temp4
);
1615 delete_insn (init_insn
);
1617 next
= NEXT_INSN (insn
);
1619 delete_insn (prev_nonnote_insn (insn
));
1625 reg_scan_update (seq
, NEXT_INSN (next
), old_max_reg
);
1626 old_max_reg
= max_reg_num ();
1636 /* Simplify if (...) x = 1; else {...} if (x) ...
1637 We recognize this case scanning backwards as well.
1639 TEMP is the assignment to x;
1640 TEMP1 is the label at the head of the second if. */
1641 /* ?? This should call get_condition to find the values being
1642 compared, instead of looking for a COMPARE insn when HAVE_cc0
1643 is not defined. This would allow it to work on the m88k. */
1644 /* ?? This optimization is only safe before cse is run if HAVE_cc0
1645 is not defined and the condition is tested by a separate compare
1646 insn. This is because the code below assumes that the result
1647 of the compare dies in the following branch.
1649 Not only that, but there might be other insns between the
1650 compare and branch whose results are live. Those insns need
1653 A way to fix this is to move the insns at JUMP_LABEL (insn)
1654 to before INSN. If we are running before flow, they will
1655 be deleted if they aren't needed. But this doesn't work
1658 This is really a special-case of jump threading, anyway. The
1659 right thing to do is to replace this and jump threading with
1660 much simpler code in cse.
1662 This code has been turned off in the non-cc0 case in the
1666 else if (this_is_simplejump
1667 /* Safe to skip USE and CLOBBER insns here
1668 since they will not be deleted. */
1669 && (temp
= prev_active_insn (insn
))
1670 && no_labels_between_p (temp
, insn
)
1671 && GET_CODE (temp
) == INSN
1672 && GET_CODE (PATTERN (temp
)) == SET
1673 && GET_CODE (SET_DEST (PATTERN (temp
))) == REG
1674 && CONSTANT_P (SET_SRC (PATTERN (temp
)))
1675 && (temp1
= next_active_insn (JUMP_LABEL (insn
)))
1676 /* If we find that the next value tested is `x'
1677 (TEMP1 is the insn where this happens), win. */
1678 && GET_CODE (temp1
) == INSN
1679 && GET_CODE (PATTERN (temp1
)) == SET
1681 /* Does temp1 `tst' the value of x? */
1682 && SET_SRC (PATTERN (temp1
)) == SET_DEST (PATTERN (temp
))
1683 && SET_DEST (PATTERN (temp1
)) == cc0_rtx
1684 && (temp1
= next_nonnote_insn (temp1
))
1686 /* Does temp1 compare the value of x against zero? */
1687 && GET_CODE (SET_SRC (PATTERN (temp1
))) == COMPARE
1688 && XEXP (SET_SRC (PATTERN (temp1
)), 1) == const0_rtx
1689 && (XEXP (SET_SRC (PATTERN (temp1
)), 0)
1690 == SET_DEST (PATTERN (temp
)))
1691 && GET_CODE (SET_DEST (PATTERN (temp1
))) == REG
1692 && (temp1
= find_next_ref (SET_DEST (PATTERN (temp1
)), temp1
))
1694 && condjump_p (temp1
))
1696 /* Get the if_then_else from the condjump. */
1697 rtx choice
= SET_SRC (PATTERN (temp1
));
1698 if (GET_CODE (choice
) == IF_THEN_ELSE
)
1700 enum rtx_code code
= GET_CODE (XEXP (choice
, 0));
1701 rtx val
= SET_SRC (PATTERN (temp
));
1703 = simplify_relational_operation (code
, GET_MODE (SET_DEST (PATTERN (temp
))),
1707 if (cond
== const_true_rtx
)
1708 ultimate
= XEXP (choice
, 1);
1709 else if (cond
== const0_rtx
)
1710 ultimate
= XEXP (choice
, 2);
1714 if (ultimate
== pc_rtx
)
1715 ultimate
= get_label_after (temp1
);
1716 else if (ultimate
&& GET_CODE (ultimate
) != RETURN
)
1717 ultimate
= XEXP (ultimate
, 0);
1719 if (ultimate
&& JUMP_LABEL(insn
) != ultimate
)
1720 changed
|= redirect_jump (insn
, ultimate
);
1726 /* @@ This needs a bit of work before it will be right.
1728 Any type of comparison can be accepted for the first and
1729 second compare. When rewriting the first jump, we must
1730 compute the what conditions can reach label3, and use the
1731 appropriate code. We can not simply reverse/swap the code
1732 of the first jump. In some cases, the second jump must be
1736 < == converts to > ==
1737 < != converts to == >
1740 If the code is written to only accept an '==' test for the second
1741 compare, then all that needs to be done is to swap the condition
1742 of the first branch.
1744 It is questionable whether we want this optimization anyways,
1745 since if the user wrote code like this because he/she knew that
1746 the jump to label1 is taken most of the time, then rewriting
1747 this gives slower code. */
1748 /* @@ This should call get_condition to find the values being
1749 compared, instead of looking for a COMPARE insn when HAVE_cc0
1750 is not defined. This would allow it to work on the m88k. */
1751 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1752 is not defined and the condition is tested by a separate compare
1753 insn. This is because the code below assumes that the result
1754 of the compare dies in the following branch. */
1756 /* Simplify test a ~= b
1770 where ~= is an inequality, e.g. >, and ~~= is the swapped
1773 We recognize this case scanning backwards.
1775 TEMP is the conditional jump to `label2';
1776 TEMP1 is the test for `a == b';
1777 TEMP2 is the conditional jump to `label1';
1778 TEMP3 is the test for `a ~= b'. */
1779 else if (this_is_simplejump
1780 && (temp
= prev_active_insn (insn
))
1781 && no_labels_between_p (temp
, insn
)
1782 && condjump_p (temp
)
1783 && (temp1
= prev_active_insn (temp
))
1784 && no_labels_between_p (temp1
, temp
)
1785 && GET_CODE (temp1
) == INSN
1786 && GET_CODE (PATTERN (temp1
)) == SET
1788 && sets_cc0_p (PATTERN (temp1
)) == 1
1790 && GET_CODE (SET_SRC (PATTERN (temp1
))) == COMPARE
1791 && GET_CODE (SET_DEST (PATTERN (temp1
))) == REG
1792 && (temp
== find_next_ref (SET_DEST (PATTERN (temp1
)), temp1
))
1794 && (temp2
= prev_active_insn (temp1
))
1795 && no_labels_between_p (temp2
, temp1
)
1796 && condjump_p (temp2
)
1797 && JUMP_LABEL (temp2
) == next_nonnote_insn (NEXT_INSN (insn
))
1798 && (temp3
= prev_active_insn (temp2
))
1799 && no_labels_between_p (temp3
, temp2
)
1800 && GET_CODE (PATTERN (temp3
)) == SET
1801 && rtx_equal_p (SET_DEST (PATTERN (temp3
)),
1802 SET_DEST (PATTERN (temp1
)))
1803 && rtx_equal_p (SET_SRC (PATTERN (temp1
)),
1804 SET_SRC (PATTERN (temp3
)))
1805 && ! inequality_comparisons_p (PATTERN (temp
))
1806 && inequality_comparisons_p (PATTERN (temp2
)))
1808 rtx fallthrough_label
= JUMP_LABEL (temp2
);
1810 ++LABEL_NUSES (fallthrough_label
);
1811 if (swap_jump (temp2
, JUMP_LABEL (insn
)))
1817 if (--LABEL_NUSES (fallthrough_label
) == 0)
1818 delete_insn (fallthrough_label
);
1821 /* Simplify if (...) {... x = 1;} if (x) ...
1823 We recognize this case backwards.
1825 TEMP is the test of `x';
1826 TEMP1 is the assignment to `x' at the end of the
1827 previous statement. */
1828 /* @@ This should call get_condition to find the values being
1829 compared, instead of looking for a COMPARE insn when HAVE_cc0
1830 is not defined. This would allow it to work on the m88k. */
1831 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1832 is not defined and the condition is tested by a separate compare
1833 insn. This is because the code below assumes that the result
1834 of the compare dies in the following branch. */
1836 /* ??? This has to be turned off. The problem is that the
1837 unconditional jump might indirectly end up branching to the
1838 label between TEMP1 and TEMP. We can't detect this, in general,
1839 since it may become a jump to there after further optimizations.
1840 If that jump is done, it will be deleted, so we will retry
1841 this optimization in the next pass, thus an infinite loop.
1843 The present code prevents this by putting the jump after the
1844 label, but this is not logically correct. */
1846 else if (this_is_condjump
1847 /* Safe to skip USE and CLOBBER insns here
1848 since they will not be deleted. */
1849 && (temp
= prev_active_insn (insn
))
1850 && no_labels_between_p (temp
, insn
)
1851 && GET_CODE (temp
) == INSN
1852 && GET_CODE (PATTERN (temp
)) == SET
1854 && sets_cc0_p (PATTERN (temp
)) == 1
1855 && GET_CODE (SET_SRC (PATTERN (temp
))) == REG
1857 /* Temp must be a compare insn, we can not accept a register
1858 to register move here, since it may not be simply a
1860 && GET_CODE (SET_SRC (PATTERN (temp
))) == COMPARE
1861 && XEXP (SET_SRC (PATTERN (temp
)), 1) == const0_rtx
1862 && GET_CODE (XEXP (SET_SRC (PATTERN (temp
)), 0)) == REG
1863 && GET_CODE (SET_DEST (PATTERN (temp
))) == REG
1864 && insn
== find_next_ref (SET_DEST (PATTERN (temp
)), temp
)
1866 /* May skip USE or CLOBBER insns here
1867 for checking for opportunity, since we
1868 take care of them later. */
1869 && (temp1
= prev_active_insn (temp
))
1870 && GET_CODE (temp1
) == INSN
1871 && GET_CODE (PATTERN (temp1
)) == SET
1873 && SET_SRC (PATTERN (temp
)) == SET_DEST (PATTERN (temp1
))
1875 && (XEXP (SET_SRC (PATTERN (temp
)), 0)
1876 == SET_DEST (PATTERN (temp1
)))
1878 && CONSTANT_P (SET_SRC (PATTERN (temp1
)))
1879 /* If this isn't true, cse will do the job. */
1880 && ! no_labels_between_p (temp1
, temp
))
1882 /* Get the if_then_else from the condjump. */
1883 rtx choice
= SET_SRC (PATTERN (insn
));
1884 if (GET_CODE (choice
) == IF_THEN_ELSE
1885 && (GET_CODE (XEXP (choice
, 0)) == EQ
1886 || GET_CODE (XEXP (choice
, 0)) == NE
))
1888 int want_nonzero
= (GET_CODE (XEXP (choice
, 0)) == NE
);
1893 /* Get the place that condjump will jump to
1894 if it is reached from here. */
1895 if ((SET_SRC (PATTERN (temp1
)) != const0_rtx
)
1897 ultimate
= XEXP (choice
, 1);
1899 ultimate
= XEXP (choice
, 2);
1900 /* Get it as a CODE_LABEL. */
1901 if (ultimate
== pc_rtx
)
1902 ultimate
= get_label_after (insn
);
1904 /* Get the label out of the LABEL_REF. */
1905 ultimate
= XEXP (ultimate
, 0);
1907 /* Insert the jump immediately before TEMP, specifically
1908 after the label that is between TEMP1 and TEMP. */
1909 last_insn
= PREV_INSN (temp
);
1911 /* If we would be branching to the next insn, the jump
1912 would immediately be deleted and the re-inserted in
1913 a subsequent pass over the code. So don't do anything
1915 if (next_active_insn (last_insn
)
1916 != next_active_insn (ultimate
))
1918 emit_barrier_after (last_insn
);
1919 p
= emit_jump_insn_after (gen_jump (ultimate
),
1921 JUMP_LABEL (p
) = ultimate
;
1922 ++LABEL_NUSES (ultimate
);
1923 if (INSN_UID (ultimate
) < max_jump_chain
1924 && INSN_CODE (p
) < max_jump_chain
)
1926 jump_chain
[INSN_UID (p
)]
1927 = jump_chain
[INSN_UID (ultimate
)];
1928 jump_chain
[INSN_UID (ultimate
)] = p
;
1937 /* Detect a conditional jump jumping over an unconditional trap. */
1939 && this_is_condjump
&& ! this_is_simplejump
1940 && reallabelprev
!= 0
1941 && GET_CODE (reallabelprev
) == INSN
1942 && GET_CODE (PATTERN (reallabelprev
)) == TRAP_IF
1943 && TRAP_CONDITION (PATTERN (reallabelprev
)) == const_true_rtx
1944 && prev_active_insn (reallabelprev
) == insn
1945 && no_labels_between_p (insn
, reallabelprev
)
1946 && (temp2
= get_condition (insn
, &temp4
))
1947 && can_reverse_comparison_p (temp2
, insn
))
1949 rtx
new = gen_cond_trap (reverse_condition (GET_CODE (temp2
)),
1950 XEXP (temp2
, 0), XEXP (temp2
, 1),
1951 TRAP_CODE (PATTERN (reallabelprev
)));
1955 emit_insn_before (new, temp4
);
1956 delete_insn (reallabelprev
);
1962 /* Detect a jump jumping to an unconditional trap. */
1963 else if (HAVE_trap
&& this_is_condjump
1964 && (temp
= next_active_insn (JUMP_LABEL (insn
)))
1965 && GET_CODE (temp
) == INSN
1966 && GET_CODE (PATTERN (temp
)) == TRAP_IF
1967 && (this_is_simplejump
1968 || (temp2
= get_condition (insn
, &temp4
))))
1970 rtx tc
= TRAP_CONDITION (PATTERN (temp
));
1972 if (tc
== const_true_rtx
1973 || (! this_is_simplejump
&& rtx_equal_p (temp2
, tc
)))
1976 /* Replace an unconditional jump to a trap with a trap. */
1977 if (this_is_simplejump
)
1979 emit_barrier_after (emit_insn_before (gen_trap (), insn
));
1984 new = gen_cond_trap (GET_CODE (temp2
), XEXP (temp2
, 0),
1986 TRAP_CODE (PATTERN (temp
)));
1989 emit_insn_before (new, temp4
);
1995 /* If the trap condition and jump condition are mutually
1996 exclusive, redirect the jump to the following insn. */
1997 else if (GET_RTX_CLASS (GET_CODE (tc
)) == '<'
1998 && ! this_is_simplejump
1999 && swap_condition (GET_CODE (temp2
)) == GET_CODE (tc
)
2000 && rtx_equal_p (XEXP (tc
, 0), XEXP (temp2
, 0))
2001 && rtx_equal_p (XEXP (tc
, 1), XEXP (temp2
, 1))
2002 && redirect_jump (insn
, get_label_after (temp
)))
2011 /* Detect a jump to a jump. */
2013 /* Look for if (foo) bar; else break; */
2014 /* The insns look like this:
2015 insn = condjump label1;
2016 ...range1 (some insns)...
2019 ...range2 (some insns)...
2020 jump somewhere unconditionally
2023 rtx label1
= next_label (insn
);
2024 rtx range1end
= label1
? prev_active_insn (label1
) : 0;
2025 /* Don't do this optimization on the first round, so that
2026 jump-around-a-jump gets simplified before we ask here
2027 whether a jump is unconditional.
2029 Also don't do it when we are called after reload since
2030 it will confuse reorg. */
2032 && (reload_completed
? ! flag_delayed_branch
: 1)
2033 /* Make sure INSN is something we can invert. */
2034 && condjump_p (insn
)
2036 && JUMP_LABEL (insn
) == label1
2037 && LABEL_NUSES (label1
) == 1
2038 && GET_CODE (range1end
) == JUMP_INSN
2039 && simplejump_p (range1end
))
2041 rtx label2
= next_label (label1
);
2042 rtx range2end
= label2
? prev_active_insn (label2
) : 0;
2043 if (range1end
!= range2end
2044 && JUMP_LABEL (range1end
) == label2
2045 && GET_CODE (range2end
) == JUMP_INSN
2046 && GET_CODE (NEXT_INSN (range2end
)) == BARRIER
2047 /* Invert the jump condition, so we
2048 still execute the same insns in each case. */
2049 && invert_jump (insn
, label1
))
2051 rtx range1beg
= next_active_insn (insn
);
2052 rtx range2beg
= next_active_insn (label1
);
2053 rtx range1after
, range2after
;
2054 rtx range1before
, range2before
;
2057 /* Include in each range any notes before it, to be
2058 sure that we get the line number note if any, even
2059 if there are other notes here. */
2060 while (PREV_INSN (range1beg
)
2061 && GET_CODE (PREV_INSN (range1beg
)) == NOTE
)
2062 range1beg
= PREV_INSN (range1beg
);
2064 while (PREV_INSN (range2beg
)
2065 && GET_CODE (PREV_INSN (range2beg
)) == NOTE
)
2066 range2beg
= PREV_INSN (range2beg
);
2068 /* Don't move NOTEs for blocks or loops; shift them
2069 outside the ranges, where they'll stay put. */
2070 range1beg
= squeeze_notes (range1beg
, range1end
);
2071 range2beg
= squeeze_notes (range2beg
, range2end
);
2073 /* Get current surrounds of the 2 ranges. */
2074 range1before
= PREV_INSN (range1beg
);
2075 range2before
= PREV_INSN (range2beg
);
2076 range1after
= NEXT_INSN (range1end
);
2077 range2after
= NEXT_INSN (range2end
);
2079 /* Splice range2 where range1 was. */
2080 NEXT_INSN (range1before
) = range2beg
;
2081 PREV_INSN (range2beg
) = range1before
;
2082 NEXT_INSN (range2end
) = range1after
;
2083 PREV_INSN (range1after
) = range2end
;
2084 /* Splice range1 where range2 was. */
2085 NEXT_INSN (range2before
) = range1beg
;
2086 PREV_INSN (range1beg
) = range2before
;
2087 NEXT_INSN (range1end
) = range2after
;
2088 PREV_INSN (range2after
) = range1end
;
2090 /* Check for a loop end note between the end of
2091 range2, and the next code label. If there is one,
2092 then what we have really seen is
2093 if (foo) break; end_of_loop;
2094 and moved the break sequence outside the loop.
2095 We must move the LOOP_END note to where the
2096 loop really ends now, or we will confuse loop
2097 optimization. Stop if we find a LOOP_BEG note
2098 first, since we don't want to move the LOOP_END
2099 note in that case. */
2100 for (;range2after
!= label2
; range2after
= rangenext
)
2102 rangenext
= NEXT_INSN (range2after
);
2103 if (GET_CODE (range2after
) == NOTE
)
2105 if (NOTE_LINE_NUMBER (range2after
)
2106 == NOTE_INSN_LOOP_END
)
2108 NEXT_INSN (PREV_INSN (range2after
))
2110 PREV_INSN (rangenext
)
2111 = PREV_INSN (range2after
);
2112 PREV_INSN (range2after
)
2113 = PREV_INSN (range1beg
);
2114 NEXT_INSN (range2after
) = range1beg
;
2115 NEXT_INSN (PREV_INSN (range1beg
))
2117 PREV_INSN (range1beg
) = range2after
;
2119 else if (NOTE_LINE_NUMBER (range2after
)
2120 == NOTE_INSN_LOOP_BEG
)
2130 /* Now that the jump has been tensioned,
2131 try cross jumping: check for identical code
2132 before the jump and before its target label. */
2134 /* First, cross jumping of conditional jumps: */
2136 if (cross_jump
&& condjump_p (insn
))
2138 rtx newjpos
, newlpos
;
2139 rtx x
= prev_real_insn (JUMP_LABEL (insn
));
2141 /* A conditional jump may be crossjumped
2142 only if the place it jumps to follows
2143 an opposing jump that comes back here. */
2145 if (x
!= 0 && ! jump_back_p (x
, insn
))
2146 /* We have no opposing jump;
2147 cannot cross jump this insn. */
2151 /* TARGET is nonzero if it is ok to cross jump
2152 to code before TARGET. If so, see if matches. */
2154 find_cross_jump (insn
, x
, 2,
2155 &newjpos
, &newlpos
);
2159 do_cross_jump (insn
, newjpos
, newlpos
);
2160 /* Make the old conditional jump
2161 into an unconditional one. */
2162 SET_SRC (PATTERN (insn
))
2163 = gen_rtx_LABEL_REF (VOIDmode
, JUMP_LABEL (insn
));
2164 INSN_CODE (insn
) = -1;
2165 emit_barrier_after (insn
);
2166 /* Add to jump_chain unless this is a new label
2167 whose UID is too large. */
2168 if (INSN_UID (JUMP_LABEL (insn
)) < max_jump_chain
)
2170 jump_chain
[INSN_UID (insn
)]
2171 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
2172 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
2179 /* Cross jumping of unconditional jumps:
2180 a few differences. */
2182 if (cross_jump
&& simplejump_p (insn
))
2184 rtx newjpos
, newlpos
;
2189 /* TARGET is nonzero if it is ok to cross jump
2190 to code before TARGET. If so, see if matches. */
2191 find_cross_jump (insn
, JUMP_LABEL (insn
), 1,
2192 &newjpos
, &newlpos
);
2194 /* If cannot cross jump to code before the label,
2195 see if we can cross jump to another jump to
2197 /* Try each other jump to this label. */
2198 if (INSN_UID (JUMP_LABEL (insn
)) < max_uid
)
2199 for (target
= jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
2200 target
!= 0 && newjpos
== 0;
2201 target
= jump_chain
[INSN_UID (target
)])
2203 && JUMP_LABEL (target
) == JUMP_LABEL (insn
)
2204 /* Ignore TARGET if it's deleted. */
2205 && ! INSN_DELETED_P (target
))
2206 find_cross_jump (insn
, target
, 2,
2207 &newjpos
, &newlpos
);
2211 do_cross_jump (insn
, newjpos
, newlpos
);
2217 /* This code was dead in the previous jump.c! */
2218 if (cross_jump
&& GET_CODE (PATTERN (insn
)) == RETURN
)
2220 /* Return insns all "jump to the same place"
2221 so we can cross-jump between any two of them. */
2223 rtx newjpos
, newlpos
, target
;
2227 /* If cannot cross jump to code before the label,
2228 see if we can cross jump to another jump to
2230 /* Try each other jump to this label. */
2231 for (target
= jump_chain
[0];
2232 target
!= 0 && newjpos
== 0;
2233 target
= jump_chain
[INSN_UID (target
)])
2235 && ! INSN_DELETED_P (target
)
2236 && GET_CODE (PATTERN (target
)) == RETURN
)
2237 find_cross_jump (insn
, target
, 2,
2238 &newjpos
, &newlpos
);
2242 do_cross_jump (insn
, newjpos
, newlpos
);
2253 /* Delete extraneous line number notes.
2254 Note that two consecutive notes for different lines are not really
2255 extraneous. There should be some indication where that line belonged,
2256 even if it became empty. */
2261 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
2262 if (GET_CODE (insn
) == NOTE
&& NOTE_LINE_NUMBER (insn
) >= 0)
2264 /* Delete this note if it is identical to previous note. */
2266 && NOTE_SOURCE_FILE (insn
) == NOTE_SOURCE_FILE (last_note
)
2267 && NOTE_LINE_NUMBER (insn
) == NOTE_LINE_NUMBER (last_note
))
2280 /* If we fall through to the epilogue, see if we can insert a RETURN insn
2281 in front of it. If the machine allows it at this point (we might be
2282 after reload for a leaf routine), it will improve optimization for it
2283 to be there. We do this both here and at the start of this pass since
2284 the RETURN might have been deleted by some of our optimizations. */
2285 insn
= get_last_insn ();
2286 while (insn
&& GET_CODE (insn
) == NOTE
)
2287 insn
= PREV_INSN (insn
);
2289 if (insn
&& GET_CODE (insn
) != BARRIER
)
2291 emit_jump_insn (gen_return ());
2297 /* CAN_REACH_END is persistent for each function. Once set it should
2298 not be cleared. This is especially true for the case where we
2299 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
2300 the front-end before compiling each function. */
2301 if (calculate_can_reach_end (last_insn
, 0, 1))
2304 /* Show JUMP_CHAIN no longer valid. */
2308 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
2309 notes whose labels don't occur in the insn any more. Returns the
2310 largest INSN_UID found. */
2315 int largest_uid
= 0;
2318 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
2320 if (GET_CODE (insn
) == CODE_LABEL
)
2321 LABEL_NUSES (insn
) = (LABEL_PRESERVE_P (insn
) != 0);
2322 else if (GET_CODE (insn
) == JUMP_INSN
)
2323 JUMP_LABEL (insn
) = 0;
2324 else if (GET_CODE (insn
) == INSN
|| GET_CODE (insn
) == CALL_INSN
)
2328 for (note
= REG_NOTES (insn
); note
; note
= next
)
2330 next
= XEXP (note
, 1);
2331 if (REG_NOTE_KIND (note
) == REG_LABEL
2332 && ! reg_mentioned_p (XEXP (note
, 0), PATTERN (insn
)))
2333 remove_note (insn
, note
);
2336 if (INSN_UID (insn
) > largest_uid
)
2337 largest_uid
= INSN_UID (insn
);
2343 /* Delete insns following barriers, up to next label.
2345 Also delete no-op jumps created by gcse. */
2347 delete_barrier_successors (f
)
2352 for (insn
= f
; insn
;)
2354 if (GET_CODE (insn
) == BARRIER
)
2356 insn
= NEXT_INSN (insn
);
2358 never_reached_warning (insn
);
2360 while (insn
!= 0 && GET_CODE (insn
) != CODE_LABEL
)
2362 if (GET_CODE (insn
) == NOTE
2363 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)
2364 insn
= NEXT_INSN (insn
);
2366 insn
= delete_insn (insn
);
2368 /* INSN is now the code_label. */
2370 /* Also remove (set (pc) (pc)) insns which can be created by
2371 gcse. We eliminate such insns now to avoid having them
2372 cause problems later. */
2373 else if (GET_CODE (insn
) == JUMP_INSN
2374 && GET_CODE (PATTERN (insn
)) == SET
2375 && SET_SRC (PATTERN (insn
)) == pc_rtx
2376 && SET_DEST (PATTERN (insn
)) == pc_rtx
)
2377 insn
= delete_insn (insn
);
2380 insn
= NEXT_INSN (insn
);
2384 /* Mark the label each jump jumps to.
2385 Combine consecutive labels, and count uses of labels.
2387 For each label, make a chain (using `jump_chain')
2388 of all the *unconditional* jumps that jump to it;
2389 also make a chain of all returns.
2391 CROSS_JUMP indicates whether we are doing cross jumping
2392 and if we are whether we will be paying attention to
2393 death notes or not. */
2396 mark_all_labels (f
, cross_jump
)
2402 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
2403 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
2405 mark_jump_label (PATTERN (insn
), insn
, cross_jump
);
2406 if (! INSN_DELETED_P (insn
) && GET_CODE (insn
) == JUMP_INSN
)
2408 if (JUMP_LABEL (insn
) != 0 && simplejump_p (insn
))
2410 jump_chain
[INSN_UID (insn
)]
2411 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
2412 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
2414 if (GET_CODE (PATTERN (insn
)) == RETURN
)
2416 jump_chain
[INSN_UID (insn
)] = jump_chain
[0];
2417 jump_chain
[0] = insn
;
2423 /* Delete all labels already not referenced.
2424 Also find and return the last insn. */
2427 delete_unreferenced_labels (f
)
2430 rtx final
= NULL_RTX
;
2433 for (insn
= f
; insn
; )
2435 if (GET_CODE (insn
) == CODE_LABEL
&& LABEL_NUSES (insn
) == 0)
2436 insn
= delete_insn (insn
);
2440 insn
= NEXT_INSN (insn
);
2447 /* Delete various simple forms of moves which have no necessary
2451 delete_noop_moves (f
)
2456 for (insn
= f
; insn
; )
2458 next
= NEXT_INSN (insn
);
2460 if (GET_CODE (insn
) == INSN
)
2462 register rtx body
= PATTERN (insn
);
2464 /* Combine stack_adjusts with following push_insns. */
2465 #ifdef PUSH_ROUNDING
2466 if (GET_CODE (body
) == SET
2467 && SET_DEST (body
) == stack_pointer_rtx
2468 && GET_CODE (SET_SRC (body
)) == PLUS
2469 && XEXP (SET_SRC (body
), 0) == stack_pointer_rtx
2470 && GET_CODE (XEXP (SET_SRC (body
), 1)) == CONST_INT
2471 && INTVAL (XEXP (SET_SRC (body
), 1)) > 0)
2474 rtx stack_adjust_insn
= insn
;
2475 int stack_adjust_amount
= INTVAL (XEXP (SET_SRC (body
), 1));
2476 int total_pushed
= 0;
2479 /* Find all successive push insns. */
2481 /* Don't convert more than three pushes;
2482 that starts adding too many displaced addresses
2483 and the whole thing starts becoming a losing
2488 p
= next_nonnote_insn (p
);
2489 if (p
== 0 || GET_CODE (p
) != INSN
)
2491 pbody
= PATTERN (p
);
2492 if (GET_CODE (pbody
) != SET
)
2494 dest
= SET_DEST (pbody
);
2495 /* Allow a no-op move between the adjust and the push. */
2496 if (GET_CODE (dest
) == REG
2497 && GET_CODE (SET_SRC (pbody
)) == REG
2498 && REGNO (dest
) == REGNO (SET_SRC (pbody
)))
2500 if (! (GET_CODE (dest
) == MEM
2501 && GET_CODE (XEXP (dest
, 0)) == POST_INC
2502 && XEXP (XEXP (dest
, 0), 0) == stack_pointer_rtx
))
2505 if (total_pushed
+ GET_MODE_SIZE (GET_MODE (SET_DEST (pbody
)))
2506 > stack_adjust_amount
)
2508 total_pushed
+= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody
)));
2511 /* Discard the amount pushed from the stack adjust;
2512 maybe eliminate it entirely. */
2513 if (total_pushed
>= stack_adjust_amount
)
2515 delete_computation (stack_adjust_insn
);
2516 total_pushed
= stack_adjust_amount
;
2519 XEXP (SET_SRC (PATTERN (stack_adjust_insn
)), 1)
2520 = GEN_INT (stack_adjust_amount
- total_pushed
);
2522 /* Change the appropriate push insns to ordinary stores. */
2524 while (total_pushed
> 0)
2527 p
= next_nonnote_insn (p
);
2528 if (GET_CODE (p
) != INSN
)
2530 pbody
= PATTERN (p
);
2531 if (GET_CODE (pbody
) != SET
)
2533 dest
= SET_DEST (pbody
);
2534 /* Allow a no-op move between the adjust and the push. */
2535 if (GET_CODE (dest
) == REG
2536 && GET_CODE (SET_SRC (pbody
)) == REG
2537 && REGNO (dest
) == REGNO (SET_SRC (pbody
)))
2539 if (! (GET_CODE (dest
) == MEM
2540 && GET_CODE (XEXP (dest
, 0)) == POST_INC
2541 && XEXP (XEXP (dest
, 0), 0) == stack_pointer_rtx
))
2543 total_pushed
-= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody
)));
2544 /* If this push doesn't fully fit in the space
2545 of the stack adjust that we deleted,
2546 make another stack adjust here for what we
2547 didn't use up. There should be peepholes
2548 to recognize the resulting sequence of insns. */
2549 if (total_pushed
< 0)
2551 emit_insn_before (gen_add2_insn (stack_pointer_rtx
,
2552 GEN_INT (- total_pushed
)),
2557 = plus_constant (stack_pointer_rtx
, total_pushed
);
2562 /* Detect and delete no-op move instructions
2563 resulting from not allocating a parameter in a register. */
2565 if (GET_CODE (body
) == SET
2566 && (SET_DEST (body
) == SET_SRC (body
)
2567 || (GET_CODE (SET_DEST (body
)) == MEM
2568 && GET_CODE (SET_SRC (body
)) == MEM
2569 && rtx_equal_p (SET_SRC (body
), SET_DEST (body
))))
2570 && ! (GET_CODE (SET_DEST (body
)) == MEM
2571 && MEM_VOLATILE_P (SET_DEST (body
)))
2572 && ! (GET_CODE (SET_SRC (body
)) == MEM
2573 && MEM_VOLATILE_P (SET_SRC (body
))))
2574 delete_computation (insn
);
2576 /* Detect and ignore no-op move instructions
2577 resulting from smart or fortuitous register allocation. */
2579 else if (GET_CODE (body
) == SET
)
2581 int sreg
= true_regnum (SET_SRC (body
));
2582 int dreg
= true_regnum (SET_DEST (body
));
2584 if (sreg
== dreg
&& sreg
>= 0)
2586 else if (sreg
>= 0 && dreg
>= 0)
2589 rtx tem
= find_equiv_reg (NULL_RTX
, insn
, 0,
2590 sreg
, NULL_PTR
, dreg
,
2591 GET_MODE (SET_SRC (body
)));
2594 && GET_MODE (tem
) == GET_MODE (SET_DEST (body
)))
2596 /* DREG may have been the target of a REG_DEAD note in
2597 the insn which makes INSN redundant. If so, reorg
2598 would still think it is dead. So search for such a
2599 note and delete it if we find it. */
2600 if (! find_regno_note (insn
, REG_UNUSED
, dreg
))
2601 for (trial
= prev_nonnote_insn (insn
);
2602 trial
&& GET_CODE (trial
) != CODE_LABEL
;
2603 trial
= prev_nonnote_insn (trial
))
2604 if (find_regno_note (trial
, REG_DEAD
, dreg
))
2606 remove_death (dreg
, trial
);
2610 /* Deleting insn could lose a death-note for SREG. */
2611 if ((trial
= find_regno_note (insn
, REG_DEAD
, sreg
)))
2613 /* Change this into a USE so that we won't emit
2614 code for it, but still can keep the note. */
2616 = gen_rtx_USE (VOIDmode
, XEXP (trial
, 0));
2617 INSN_CODE (insn
) = -1;
2618 /* Remove all reg notes but the REG_DEAD one. */
2619 REG_NOTES (insn
) = trial
;
2620 XEXP (trial
, 1) = NULL_RTX
;
2626 else if (dreg
>= 0 && CONSTANT_P (SET_SRC (body
))
2627 && find_equiv_reg (SET_SRC (body
), insn
, 0, dreg
,
2629 GET_MODE (SET_DEST (body
))))
2631 /* This handles the case where we have two consecutive
2632 assignments of the same constant to pseudos that didn't
2633 get a hard reg. Each SET from the constant will be
2634 converted into a SET of the spill register and an
2635 output reload will be made following it. This produces
2636 two loads of the same constant into the same spill
2641 /* Look back for a death note for the first reg.
2642 If there is one, it is no longer accurate. */
2643 while (in_insn
&& GET_CODE (in_insn
) != CODE_LABEL
)
2645 if ((GET_CODE (in_insn
) == INSN
2646 || GET_CODE (in_insn
) == JUMP_INSN
)
2647 && find_regno_note (in_insn
, REG_DEAD
, dreg
))
2649 remove_death (dreg
, in_insn
);
2652 in_insn
= PREV_INSN (in_insn
);
2655 /* Delete the second load of the value. */
2659 else if (GET_CODE (body
) == PARALLEL
)
2661 /* If each part is a set between two identical registers or
2662 a USE or CLOBBER, delete the insn. */
2666 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; i
--)
2668 tem
= XVECEXP (body
, 0, i
);
2669 if (GET_CODE (tem
) == USE
|| GET_CODE (tem
) == CLOBBER
)
2672 if (GET_CODE (tem
) != SET
2673 || (sreg
= true_regnum (SET_SRC (tem
))) < 0
2674 || (dreg
= true_regnum (SET_DEST (tem
))) < 0
2682 /* Also delete insns to store bit fields if they are no-ops. */
2683 /* Not worth the hair to detect this in the big-endian case. */
2684 else if (! BYTES_BIG_ENDIAN
2685 && GET_CODE (body
) == SET
2686 && GET_CODE (SET_DEST (body
)) == ZERO_EXTRACT
2687 && XEXP (SET_DEST (body
), 2) == const0_rtx
2688 && XEXP (SET_DEST (body
), 0) == SET_SRC (body
)
2689 && ! (GET_CODE (SET_SRC (body
)) == MEM
2690 && MEM_VOLATILE_P (SET_SRC (body
))))
2697 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
2698 If so indicate that this function can drop off the end by returning
2701 CHECK_DELETED indicates whether we must check if the note being
2702 searched for has the deleted flag set.
2704 DELETE_FINAL_NOTE indicates whether we should delete the note
2708 calculate_can_reach_end (last
, check_deleted
, delete_final_note
)
2711 int delete_final_note
;
2716 while (insn
!= NULL_RTX
)
2720 /* One label can follow the end-note: the return label. */
2721 if (GET_CODE (insn
) == CODE_LABEL
&& n_labels
-- > 0)
2723 /* Ordinary insns can follow it if returning a structure. */
2724 else if (GET_CODE (insn
) == INSN
)
2726 /* If machine uses explicit RETURN insns, no epilogue,
2727 then one of them follows the note. */
2728 else if (GET_CODE (insn
) == JUMP_INSN
2729 && GET_CODE (PATTERN (insn
)) == RETURN
)
2731 /* A barrier can follow the return insn. */
2732 else if (GET_CODE (insn
) == BARRIER
)
2734 /* Other kinds of notes can follow also. */
2735 else if (GET_CODE (insn
) == NOTE
2736 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)
2742 insn
= PREV_INSN (insn
);
2745 /* See if we backed up to the appropriate type of note. */
2746 if (insn
!= NULL_RTX
2747 && GET_CODE (insn
) == NOTE
2748 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_FUNCTION_END
2749 && (check_deleted
== 0
2750 || ! INSN_DELETED_P (insn
)))
2752 if (delete_final_note
)
2760 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
2761 jump. Assume that this unconditional jump is to the exit test code. If
2762 the code is sufficiently simple, make a copy of it before INSN,
2763 followed by a jump to the exit of the loop. Then delete the unconditional
2766 Return 1 if we made the change, else 0.
2768 This is only safe immediately after a regscan pass because it uses the
2769 values of regno_first_uid and regno_last_uid. */
2772 duplicate_loop_exit_test (loop_start
)
2775 rtx insn
, set
, reg
, p
, link
;
2776 rtx copy
= 0, first_copy
= 0;
2778 rtx exitcode
= NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start
)));
2780 int max_reg
= max_reg_num ();
2783 /* Scan the exit code. We do not perform this optimization if any insn:
2787 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
2788 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
2789 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
2792 We also do not do this if we find an insn with ASM_OPERANDS. While
2793 this restriction should not be necessary, copying an insn with
2794 ASM_OPERANDS can confuse asm_noperands in some cases.
2796 Also, don't do this if the exit code is more than 20 insns. */
2798 for (insn
= exitcode
;
2800 && ! (GET_CODE (insn
) == NOTE
2801 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
);
2802 insn
= NEXT_INSN (insn
))
2804 switch (GET_CODE (insn
))
2810 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
2811 a jump immediately after the loop start that branches outside
2812 the loop but within an outer loop, near the exit test.
2813 If we copied this exit test and created a phony
2814 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
2815 before the exit test look like these could be safely moved
2816 out of the loop even if they actually may be never executed.
2817 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
2819 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
2820 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
)
2824 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
2825 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
))
2826 /* If we were to duplicate this code, we would not move
2827 the BLOCK notes, and so debugging the moved code would
2828 be difficult. Thus, we only move the code with -O2 or
2835 /* The code below would grossly mishandle REG_WAS_0 notes,
2836 so get rid of them here. */
2837 while ((p
= find_reg_note (insn
, REG_WAS_0
, NULL_RTX
)) != 0)
2838 remove_note (insn
, p
);
2839 if (++num_insns
> 20
2840 || find_reg_note (insn
, REG_RETVAL
, NULL_RTX
)
2841 || find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
2849 /* Unless INSN is zero, we can do the optimization. */
2855 /* See if any insn sets a register only used in the loop exit code and
2856 not a user variable. If so, replace it with a new register. */
2857 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
2858 if (GET_CODE (insn
) == INSN
2859 && (set
= single_set (insn
)) != 0
2860 && ((reg
= SET_DEST (set
), GET_CODE (reg
) == REG
)
2861 || (GET_CODE (reg
) == SUBREG
2862 && (reg
= SUBREG_REG (reg
), GET_CODE (reg
) == REG
)))
2863 && REGNO (reg
) >= FIRST_PSEUDO_REGISTER
2864 && REGNO_FIRST_UID (REGNO (reg
)) == INSN_UID (insn
))
2866 for (p
= NEXT_INSN (insn
); p
!= lastexit
; p
= NEXT_INSN (p
))
2867 if (REGNO_LAST_UID (REGNO (reg
)) == INSN_UID (p
))
2872 /* We can do the replacement. Allocate reg_map if this is the
2873 first replacement we found. */
2876 reg_map
= (rtx
*) alloca (max_reg
* sizeof (rtx
));
2877 bzero ((char *) reg_map
, max_reg
* sizeof (rtx
));
2880 REG_LOOP_TEST_P (reg
) = 1;
2882 reg_map
[REGNO (reg
)] = gen_reg_rtx (GET_MODE (reg
));
2886 /* Now copy each insn. */
2887 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
2889 switch (GET_CODE (insn
))
2892 copy
= emit_barrier_before (loop_start
);
2895 /* Only copy line-number notes. */
2896 if (NOTE_LINE_NUMBER (insn
) >= 0)
2898 copy
= emit_note_before (NOTE_LINE_NUMBER (insn
), loop_start
);
2899 NOTE_SOURCE_FILE (copy
) = NOTE_SOURCE_FILE (insn
);
2904 copy
= emit_insn_before (copy_insn (PATTERN (insn
)), loop_start
);
2906 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
2908 mark_jump_label (PATTERN (copy
), copy
, 0);
2910 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
2912 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2913 if (REG_NOTE_KIND (link
) != REG_LABEL
)
2915 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link
),
2918 if (reg_map
&& REG_NOTES (copy
))
2919 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
2923 copy
= emit_jump_insn_before (copy_insn (PATTERN (insn
)), loop_start
);
2925 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
2926 mark_jump_label (PATTERN (copy
), copy
, 0);
2927 if (REG_NOTES (insn
))
2929 REG_NOTES (copy
) = copy_insn_1 (REG_NOTES (insn
));
2931 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
2934 /* If this is a simple jump, add it to the jump chain. */
2936 if (INSN_UID (copy
) < max_jump_chain
&& JUMP_LABEL (copy
)
2937 && simplejump_p (copy
))
2939 jump_chain
[INSN_UID (copy
)]
2940 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
2941 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
2949 /* Record the first insn we copied. We need it so that we can
2950 scan the copied insns for new pseudo registers. */
2955 /* Now clean up by emitting a jump to the end label and deleting the jump
2956 at the start of the loop. */
2957 if (! copy
|| GET_CODE (copy
) != BARRIER
)
2959 copy
= emit_jump_insn_before (gen_jump (get_label_after (insn
)),
2962 /* Record the first insn we copied. We need it so that we can
2963 scan the copied insns for new pseudo registers. This may not
2964 be strictly necessary since we should have copied at least one
2965 insn above. But I am going to be safe. */
2969 mark_jump_label (PATTERN (copy
), copy
, 0);
2970 if (INSN_UID (copy
) < max_jump_chain
2971 && INSN_UID (JUMP_LABEL (copy
)) < max_jump_chain
)
2973 jump_chain
[INSN_UID (copy
)]
2974 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
2975 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
2977 emit_barrier_before (loop_start
);
2980 /* Now scan from the first insn we copied to the last insn we copied
2981 (copy) for new pseudo registers. Do this after the code to jump to
2982 the end label since that might create a new pseudo too. */
2983 reg_scan_update (first_copy
, copy
, max_reg
);
2985 /* Mark the exit code as the virtual top of the converted loop. */
2986 emit_note_before (NOTE_INSN_LOOP_VTOP
, exitcode
);
2988 delete_insn (next_nonnote_insn (loop_start
));
2993 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
2994 loop-end notes between START and END out before START. Assume that
2995 END is not such a note. START may be such a note. Returns the value
2996 of the new starting insn, which may be different if the original start
3000 squeeze_notes (start
, end
)
3006 for (insn
= start
; insn
!= end
; insn
= next
)
3008 next
= NEXT_INSN (insn
);
3009 if (GET_CODE (insn
) == NOTE
3010 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
3011 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
3012 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
3013 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
3014 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
3015 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_VTOP
))
3021 rtx prev
= PREV_INSN (insn
);
3022 PREV_INSN (insn
) = PREV_INSN (start
);
3023 NEXT_INSN (insn
) = start
;
3024 NEXT_INSN (PREV_INSN (insn
)) = insn
;
3025 PREV_INSN (NEXT_INSN (insn
)) = insn
;
3026 NEXT_INSN (prev
) = next
;
3027 PREV_INSN (next
) = prev
;
3035 /* Compare the instructions before insn E1 with those before E2
3036 to find an opportunity for cross jumping.
3037 (This means detecting identical sequences of insns followed by
3038 jumps to the same place, or followed by a label and a jump
3039 to that label, and replacing one with a jump to the other.)
3041 Assume E1 is a jump that jumps to label E2
3042 (that is not always true but it might as well be).
3043 Find the longest possible equivalent sequences
3044 and store the first insns of those sequences into *F1 and *F2.
3045 Store zero there if no equivalent preceding instructions are found.
3047 We give up if we find a label in stream 1.
3048 Actually we could transfer that label into stream 2. */
3051 find_cross_jump (e1
, e2
, minimum
, f1
, f2
)
3056 register rtx i1
= e1
, i2
= e2
;
3057 register rtx p1
, p2
;
3060 rtx last1
= 0, last2
= 0;
3061 rtx afterlast1
= 0, afterlast2
= 0;
3068 i1
= prev_nonnote_insn (i1
);
3070 i2
= PREV_INSN (i2
);
3071 while (i2
&& (GET_CODE (i2
) == NOTE
|| GET_CODE (i2
) == CODE_LABEL
))
3072 i2
= PREV_INSN (i2
);
3077 /* Don't allow the range of insns preceding E1 or E2
3078 to include the other (E2 or E1). */
3079 if (i2
== e1
|| i1
== e2
)
3082 /* If we will get to this code by jumping, those jumps will be
3083 tensioned to go directly to the new label (before I2),
3084 so this cross-jumping won't cost extra. So reduce the minimum. */
3085 if (GET_CODE (i1
) == CODE_LABEL
)
3091 if (i2
== 0 || GET_CODE (i1
) != GET_CODE (i2
))
3094 /* Avoid moving insns across EH regions if either of the insns
3097 && (asynchronous_exceptions
|| GET_CODE (i1
) == CALL_INSN
)
3098 && !in_same_eh_region (i1
, i2
))
3104 /* If this is a CALL_INSN, compare register usage information.
3105 If we don't check this on stack register machines, the two
3106 CALL_INSNs might be merged leaving reg-stack.c with mismatching
3107 numbers of stack registers in the same basic block.
3108 If we don't check this on machines with delay slots, a delay slot may
3109 be filled that clobbers a parameter expected by the subroutine.
3111 ??? We take the simple route for now and assume that if they're
3112 equal, they were constructed identically. */
3114 if (GET_CODE (i1
) == CALL_INSN
3115 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1
),
3116 CALL_INSN_FUNCTION_USAGE (i2
)))
3120 /* If cross_jump_death_matters is not 0, the insn's mode
3121 indicates whether or not the insn contains any stack-like
3124 if (!lose
&& cross_jump_death_matters
&& stack_regs_mentioned (i1
))
3126 /* If register stack conversion has already been done, then
3127 death notes must also be compared before it is certain that
3128 the two instruction streams match. */
3131 HARD_REG_SET i1_regset
, i2_regset
;
3133 CLEAR_HARD_REG_SET (i1_regset
);
3134 CLEAR_HARD_REG_SET (i2_regset
);
3136 for (note
= REG_NOTES (i1
); note
; note
= XEXP (note
, 1))
3137 if (REG_NOTE_KIND (note
) == REG_DEAD
3138 && STACK_REG_P (XEXP (note
, 0)))
3139 SET_HARD_REG_BIT (i1_regset
, REGNO (XEXP (note
, 0)));
3141 for (note
= REG_NOTES (i2
); note
; note
= XEXP (note
, 1))
3142 if (REG_NOTE_KIND (note
) == REG_DEAD
3143 && STACK_REG_P (XEXP (note
, 0)))
3144 SET_HARD_REG_BIT (i2_regset
, REGNO (XEXP (note
, 0)));
3146 GO_IF_HARD_REG_EQUAL (i1_regset
, i2_regset
, done
);
3155 /* Don't allow old-style asm or volatile extended asms to be accepted
3156 for cross jumping purposes. It is conceptually correct to allow
3157 them, since cross-jumping preserves the dynamic instruction order
3158 even though it is changing the static instruction order. However,
3159 if an asm is being used to emit an assembler pseudo-op, such as
3160 the MIPS `.set reorder' pseudo-op, then the static instruction order
3161 matters and it must be preserved. */
3162 if (GET_CODE (p1
) == ASM_INPUT
|| GET_CODE (p2
) == ASM_INPUT
3163 || (GET_CODE (p1
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p1
))
3164 || (GET_CODE (p2
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p2
)))
3167 if (lose
|| GET_CODE (p1
) != GET_CODE (p2
)
3168 || ! rtx_renumbered_equal_p (p1
, p2
))
3170 /* The following code helps take care of G++ cleanups. */
3174 if (!lose
&& GET_CODE (p1
) == GET_CODE (p2
)
3175 && ((equiv1
= find_reg_note (i1
, REG_EQUAL
, NULL_RTX
)) != 0
3176 || (equiv1
= find_reg_note (i1
, REG_EQUIV
, NULL_RTX
)) != 0)
3177 && ((equiv2
= find_reg_note (i2
, REG_EQUAL
, NULL_RTX
)) != 0
3178 || (equiv2
= find_reg_note (i2
, REG_EQUIV
, NULL_RTX
)) != 0)
3179 /* If the equivalences are not to a constant, they may
3180 reference pseudos that no longer exist, so we can't
3182 && CONSTANT_P (XEXP (equiv1
, 0))
3183 && rtx_equal_p (XEXP (equiv1
, 0), XEXP (equiv2
, 0)))
3185 rtx s1
= single_set (i1
);
3186 rtx s2
= single_set (i2
);
3187 if (s1
!= 0 && s2
!= 0
3188 && rtx_renumbered_equal_p (SET_DEST (s1
), SET_DEST (s2
)))
3190 validate_change (i1
, &SET_SRC (s1
), XEXP (equiv1
, 0), 1);
3191 validate_change (i2
, &SET_SRC (s2
), XEXP (equiv2
, 0), 1);
3192 if (! rtx_renumbered_equal_p (p1
, p2
))
3194 else if (apply_change_group ())
3199 /* Insns fail to match; cross jumping is limited to the following
3203 /* Don't allow the insn after a compare to be shared by
3204 cross-jumping unless the compare is also shared.
3205 Here, if either of these non-matching insns is a compare,
3206 exclude the following insn from possible cross-jumping. */
3207 if (sets_cc0_p (p1
) || sets_cc0_p (p2
))
3208 last1
= afterlast1
, last2
= afterlast2
, ++minimum
;
3211 /* If cross-jumping here will feed a jump-around-jump
3212 optimization, this jump won't cost extra, so reduce
3214 if (GET_CODE (i1
) == JUMP_INSN
3216 && prev_real_insn (JUMP_LABEL (i1
)) == e1
)
3222 if (GET_CODE (p1
) != USE
&& GET_CODE (p1
) != CLOBBER
)
3224 /* Ok, this insn is potentially includable in a cross-jump here. */
3225 afterlast1
= last1
, afterlast2
= last2
;
3226 last1
= i1
, last2
= i2
, --minimum
;
3230 if (minimum
<= 0 && last1
!= 0 && last1
!= e1
)
3231 *f1
= last1
, *f2
= last2
;
3235 do_cross_jump (insn
, newjpos
, newlpos
)
3236 rtx insn
, newjpos
, newlpos
;
3238 /* Find an existing label at this point
3239 or make a new one if there is none. */
3240 register rtx label
= get_label_before (newlpos
);
3242 /* Make the same jump insn jump to the new point. */
3243 if (GET_CODE (PATTERN (insn
)) == RETURN
)
3245 /* Remove from jump chain of returns. */
3246 delete_from_jump_chain (insn
);
3247 /* Change the insn. */
3248 PATTERN (insn
) = gen_jump (label
);
3249 INSN_CODE (insn
) = -1;
3250 JUMP_LABEL (insn
) = label
;
3251 LABEL_NUSES (label
)++;
3252 /* Add to new the jump chain. */
3253 if (INSN_UID (label
) < max_jump_chain
3254 && INSN_UID (insn
) < max_jump_chain
)
3256 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (label
)];
3257 jump_chain
[INSN_UID (label
)] = insn
;
3261 redirect_jump (insn
, label
);
3263 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
3264 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
3265 the NEWJPOS stream. */
3267 while (newjpos
!= insn
)
3271 for (lnote
= REG_NOTES (newlpos
); lnote
; lnote
= XEXP (lnote
, 1))
3272 if ((REG_NOTE_KIND (lnote
) == REG_EQUAL
3273 || REG_NOTE_KIND (lnote
) == REG_EQUIV
)
3274 && ! find_reg_note (newjpos
, REG_EQUAL
, XEXP (lnote
, 0))
3275 && ! find_reg_note (newjpos
, REG_EQUIV
, XEXP (lnote
, 0)))
3276 remove_note (newlpos
, lnote
);
3278 delete_insn (newjpos
);
3279 newjpos
= next_real_insn (newjpos
);
3280 newlpos
= next_real_insn (newlpos
);
3284 /* Return the label before INSN, or put a new label there. */
3287 get_label_before (insn
)
3292 /* Find an existing label at this point
3293 or make a new one if there is none. */
3294 label
= prev_nonnote_insn (insn
);
3296 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
3298 rtx prev
= PREV_INSN (insn
);
3300 label
= gen_label_rtx ();
3301 emit_label_after (label
, prev
);
3302 LABEL_NUSES (label
) = 0;
3307 /* Return the label after INSN, or put a new label there. */
3310 get_label_after (insn
)
3315 /* Find an existing label at this point
3316 or make a new one if there is none. */
3317 label
= next_nonnote_insn (insn
);
3319 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
3321 label
= gen_label_rtx ();
3322 emit_label_after (label
, insn
);
3323 LABEL_NUSES (label
) = 0;
3328 /* Return 1 if INSN is a jump that jumps to right after TARGET
3329 only on the condition that TARGET itself would drop through.
3330 Assumes that TARGET is a conditional jump. */
3333 jump_back_p (insn
, target
)
3337 enum rtx_code codei
, codet
;
3339 if (simplejump_p (insn
) || ! condjump_p (insn
)
3340 || simplejump_p (target
)
3341 || target
!= prev_real_insn (JUMP_LABEL (insn
)))
3344 cinsn
= XEXP (SET_SRC (PATTERN (insn
)), 0);
3345 ctarget
= XEXP (SET_SRC (PATTERN (target
)), 0);
3347 codei
= GET_CODE (cinsn
);
3348 codet
= GET_CODE (ctarget
);
3350 if (XEXP (SET_SRC (PATTERN (insn
)), 1) == pc_rtx
)
3352 if (! can_reverse_comparison_p (cinsn
, insn
))
3354 codei
= reverse_condition (codei
);
3357 if (XEXP (SET_SRC (PATTERN (target
)), 2) == pc_rtx
)
3359 if (! can_reverse_comparison_p (ctarget
, target
))
3361 codet
= reverse_condition (codet
);
3364 return (codei
== codet
3365 && rtx_renumbered_equal_p (XEXP (cinsn
, 0), XEXP (ctarget
, 0))
3366 && rtx_renumbered_equal_p (XEXP (cinsn
, 1), XEXP (ctarget
, 1)));
3369 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
3370 return non-zero if it is safe to reverse this comparison. It is if our
3371 floating-point is not IEEE, if this is an NE or EQ comparison, or if
3372 this is known to be an integer comparison. */
3375 can_reverse_comparison_p (comparison
, insn
)
3381 /* If this is not actually a comparison, we can't reverse it. */
3382 if (GET_RTX_CLASS (GET_CODE (comparison
)) != '<')
3385 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
3386 /* If this is an NE comparison, it is safe to reverse it to an EQ
3387 comparison and vice versa, even for floating point. If no operands
3388 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
3389 always false and NE is always true, so the reversal is also valid. */
3391 || GET_CODE (comparison
) == NE
3392 || GET_CODE (comparison
) == EQ
)
3395 arg0
= XEXP (comparison
, 0);
3397 /* Make sure ARG0 is one of the actual objects being compared. If we
3398 can't do this, we can't be sure the comparison can be reversed.
3400 Handle cc0 and a MODE_CC register. */
3401 if ((GET_CODE (arg0
) == REG
&& GET_MODE_CLASS (GET_MODE (arg0
)) == MODE_CC
)
3407 rtx prev
= prev_nonnote_insn (insn
);
3410 /* First see if the condition code mode alone if enough to say we can
3411 reverse the condition. If not, then search backwards for a set of
3412 ARG0. We do not need to check for an insn clobbering it since valid
3413 code will contain set a set with no intervening clobber. But
3414 stop when we reach a label. */
3415 #ifdef REVERSIBLE_CC_MODE
3416 if (GET_MODE_CLASS (GET_MODE (arg0
)) == MODE_CC
3417 && REVERSIBLE_CC_MODE (GET_MODE (arg0
)))
3421 for (prev
= prev_nonnote_insn (insn
);
3422 prev
!= 0 && GET_CODE (prev
) != CODE_LABEL
;
3423 prev
= prev_nonnote_insn (prev
))
3424 if ((set
= single_set (prev
)) != 0
3425 && rtx_equal_p (SET_DEST (set
), arg0
))
3427 arg0
= SET_SRC (set
);
3429 if (GET_CODE (arg0
) == COMPARE
)
3430 arg0
= XEXP (arg0
, 0);
3435 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
3436 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
3437 return (GET_CODE (arg0
) == CONST_INT
3438 || (GET_MODE (arg0
) != VOIDmode
3439 && GET_MODE_CLASS (GET_MODE (arg0
)) != MODE_CC
3440 && GET_MODE_CLASS (GET_MODE (arg0
)) != MODE_FLOAT
));
3443 /* Given an rtx-code for a comparison, return the code
3444 for the negated comparison.
3445 WATCH OUT! reverse_condition is not safe to use on a jump
3446 that might be acting on the results of an IEEE floating point comparison,
3447 because of the special treatment of non-signaling nans in comparisons.
3448 Use can_reverse_comparison_p to be sure. */
3451 reverse_condition (code
)
3492 /* Similar, but return the code when two operands of a comparison are swapped.
3493 This IS safe for IEEE floating-point. */
3496 swap_condition (code
)
3535 /* Given a comparison CODE, return the corresponding unsigned comparison.
3536 If CODE is an equality comparison or already an unsigned comparison,
3537 CODE is returned. */
3540 unsigned_condition (code
)
3570 /* Similarly, return the signed version of a comparison. */
3573 signed_condition (code
)
3603 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
3604 truth of CODE1 implies the truth of CODE2. */
3607 comparison_dominates_p (code1
, code2
)
3608 enum rtx_code code1
, code2
;
3616 if (code2
== LE
|| code2
== LEU
|| code2
== GE
|| code2
== GEU
)
3621 if (code2
== LE
|| code2
== NE
)
3626 if (code2
== GE
|| code2
== NE
)
3631 if (code2
== LEU
|| code2
== NE
)
3636 if (code2
== GEU
|| code2
== NE
)
3647 /* Return 1 if INSN is an unconditional jump and nothing else. */
3653 return (GET_CODE (insn
) == JUMP_INSN
3654 && GET_CODE (PATTERN (insn
)) == SET
3655 && GET_CODE (SET_DEST (PATTERN (insn
))) == PC
3656 && GET_CODE (SET_SRC (PATTERN (insn
))) == LABEL_REF
);
3659 /* Return nonzero if INSN is a (possibly) conditional jump
3660 and nothing more. */
3666 register rtx x
= PATTERN (insn
);
3668 if (GET_CODE (x
) != SET
3669 || GET_CODE (SET_DEST (x
)) != PC
)
3673 if (GET_CODE (x
) == LABEL_REF
)
3675 else return (GET_CODE (x
) == IF_THEN_ELSE
3676 && ((GET_CODE (XEXP (x
, 2)) == PC
3677 && (GET_CODE (XEXP (x
, 1)) == LABEL_REF
3678 || GET_CODE (XEXP (x
, 1)) == RETURN
))
3679 || (GET_CODE (XEXP (x
, 1)) == PC
3680 && (GET_CODE (XEXP (x
, 2)) == LABEL_REF
3681 || GET_CODE (XEXP (x
, 2)) == RETURN
))));
3686 /* Return nonzero if INSN is a (possibly) conditional jump inside a
3690 condjump_in_parallel_p (insn
)
3693 register rtx x
= PATTERN (insn
);
3695 if (GET_CODE (x
) != PARALLEL
)
3698 x
= XVECEXP (x
, 0, 0);
3700 if (GET_CODE (x
) != SET
)
3702 if (GET_CODE (SET_DEST (x
)) != PC
)
3704 if (GET_CODE (SET_SRC (x
)) == LABEL_REF
)
3706 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
3708 if (XEXP (SET_SRC (x
), 2) == pc_rtx
3709 && (GET_CODE (XEXP (SET_SRC (x
), 1)) == LABEL_REF
3710 || GET_CODE (XEXP (SET_SRC (x
), 1)) == RETURN
))
3712 if (XEXP (SET_SRC (x
), 1) == pc_rtx
3713 && (GET_CODE (XEXP (SET_SRC (x
), 2)) == LABEL_REF
3714 || GET_CODE (XEXP (SET_SRC (x
), 2)) == RETURN
))
3719 /* Return the label of a conditional jump. */
3722 condjump_label (insn
)
3725 register rtx x
= PATTERN (insn
);
3727 if (GET_CODE (x
) == PARALLEL
)
3728 x
= XVECEXP (x
, 0, 0);
3729 if (GET_CODE (x
) != SET
)
3731 if (GET_CODE (SET_DEST (x
)) != PC
)
3734 if (GET_CODE (x
) == LABEL_REF
)
3736 if (GET_CODE (x
) != IF_THEN_ELSE
)
3738 if (XEXP (x
, 2) == pc_rtx
&& GET_CODE (XEXP (x
, 1)) == LABEL_REF
)
3740 if (XEXP (x
, 1) == pc_rtx
&& GET_CODE (XEXP (x
, 2)) == LABEL_REF
)
3745 /* Return true if INSN is a (possibly conditional) return insn. */
3748 returnjump_p_1 (loc
, data
)
3750 void *data ATTRIBUTE_UNUSED
;
3753 return GET_CODE (x
) == RETURN
;
3760 return for_each_rtx (&PATTERN (insn
), returnjump_p_1
, NULL
);
3763 /* Return true if INSN is a jump that only transfers control and
3772 if (GET_CODE (insn
) != JUMP_INSN
)
3775 set
= single_set (insn
);
3778 if (GET_CODE (SET_DEST (set
)) != PC
)
3780 if (side_effects_p (SET_SRC (set
)))
3788 /* Return 1 if X is an RTX that does nothing but set the condition codes
3789 and CLOBBER or USE registers.
3790 Return -1 if X does explicitly set the condition codes,
3791 but also does other things. */
3795 rtx x ATTRIBUTE_UNUSED
;
3797 if (GET_CODE (x
) == SET
&& SET_DEST (x
) == cc0_rtx
)
3799 if (GET_CODE (x
) == PARALLEL
)
3803 int other_things
= 0;
3804 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
3806 if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
3807 && SET_DEST (XVECEXP (x
, 0, i
)) == cc0_rtx
)
3809 else if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
)
3812 return ! sets_cc0
? 0 : other_things
? -1 : 1;
3818 /* Follow any unconditional jump at LABEL;
3819 return the ultimate label reached by any such chain of jumps.
3820 If LABEL is not followed by a jump, return LABEL.
3821 If the chain loops or we can't find end, return LABEL,
3822 since that tells caller to avoid changing the insn.
3824 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
3825 a USE or CLOBBER. */
3828 follow_jumps (label
)
3833 register rtx value
= label
;
3838 && (insn
= next_active_insn (value
)) != 0
3839 && GET_CODE (insn
) == JUMP_INSN
3840 && ((JUMP_LABEL (insn
) != 0 && simplejump_p (insn
))
3841 || GET_CODE (PATTERN (insn
)) == RETURN
)
3842 && (next
= NEXT_INSN (insn
))
3843 && GET_CODE (next
) == BARRIER
);
3846 /* Don't chain through the insn that jumps into a loop
3847 from outside the loop,
3848 since that would create multiple loop entry jumps
3849 and prevent loop optimization. */
3851 if (!reload_completed
)
3852 for (tem
= value
; tem
!= insn
; tem
= NEXT_INSN (tem
))
3853 if (GET_CODE (tem
) == NOTE
3854 && (NOTE_LINE_NUMBER (tem
) == NOTE_INSN_LOOP_BEG
3855 /* ??? Optional. Disables some optimizations, but makes
3856 gcov output more accurate with -O. */
3857 || (flag_test_coverage
&& NOTE_LINE_NUMBER (tem
) > 0)))
3860 /* If we have found a cycle, make the insn jump to itself. */
3861 if (JUMP_LABEL (insn
) == label
)
3864 tem
= next_active_insn (JUMP_LABEL (insn
));
3865 if (tem
&& (GET_CODE (PATTERN (tem
)) == ADDR_VEC
3866 || GET_CODE (PATTERN (tem
)) == ADDR_DIFF_VEC
))
3869 value
= JUMP_LABEL (insn
);
3876 /* Assuming that field IDX of X is a vector of label_refs,
3877 replace each of them by the ultimate label reached by it.
3878 Return nonzero if a change is made.
3879 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
3882 tension_vector_labels (x
, idx
)
3888 for (i
= XVECLEN (x
, idx
) - 1; i
>= 0; i
--)
3890 register rtx olabel
= XEXP (XVECEXP (x
, idx
, i
), 0);
3891 register rtx nlabel
= follow_jumps (olabel
);
3892 if (nlabel
&& nlabel
!= olabel
)
3894 XEXP (XVECEXP (x
, idx
, i
), 0) = nlabel
;
3895 ++LABEL_NUSES (nlabel
);
3896 if (--LABEL_NUSES (olabel
) == 0)
3897 delete_insn (olabel
);
3904 /* Find all CODE_LABELs referred to in X, and increment their use counts.
3905 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
3906 in INSN, then store one of them in JUMP_LABEL (INSN).
3907 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
3908 referenced in INSN, add a REG_LABEL note containing that label to INSN.
3909 Also, when there are consecutive labels, canonicalize on the last of them.
3911 Note that two labels separated by a loop-beginning note
3912 must be kept distinct if we have not yet done loop-optimization,
3913 because the gap between them is where loop-optimize
3914 will want to move invariant code to. CROSS_JUMP tells us
3915 that loop-optimization is done with.
3917 Once reload has completed (CROSS_JUMP non-zero), we need not consider
3918 two labels distinct if they are separated by only USE or CLOBBER insns. */
3921 mark_jump_label (x
, insn
, cross_jump
)
3926 register RTX_CODE code
= GET_CODE (x
);
3928 register const char *fmt
;
3944 /* If this is a constant-pool reference, see if it is a label. */
3945 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3946 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3947 mark_jump_label (get_pool_constant (XEXP (x
, 0)), insn
, cross_jump
);
3952 rtx label
= XEXP (x
, 0);
3957 if (GET_CODE (label
) != CODE_LABEL
)
3960 /* Ignore references to labels of containing functions. */
3961 if (LABEL_REF_NONLOCAL_P (x
))
3964 /* If there are other labels following this one,
3965 replace it with the last of the consecutive labels. */
3966 for (next
= NEXT_INSN (label
); next
; next
= NEXT_INSN (next
))
3968 if (GET_CODE (next
) == CODE_LABEL
)
3970 else if (cross_jump
&& GET_CODE (next
) == INSN
3971 && (GET_CODE (PATTERN (next
)) == USE
3972 || GET_CODE (PATTERN (next
)) == CLOBBER
))
3974 else if (GET_CODE (next
) != NOTE
)
3976 else if (! cross_jump
3977 && (NOTE_LINE_NUMBER (next
) == NOTE_INSN_LOOP_BEG
3978 || NOTE_LINE_NUMBER (next
) == NOTE_INSN_FUNCTION_END
3979 /* ??? Optional. Disables some optimizations, but
3980 makes gcov output more accurate with -O. */
3981 || (flag_test_coverage
&& NOTE_LINE_NUMBER (next
) > 0)))
3985 XEXP (x
, 0) = label
;
3986 if (! insn
|| ! INSN_DELETED_P (insn
))
3987 ++LABEL_NUSES (label
);
3991 if (GET_CODE (insn
) == JUMP_INSN
)
3992 JUMP_LABEL (insn
) = label
;
3994 /* If we've changed OLABEL and we had a REG_LABEL note
3995 for it, update it as well. */
3996 else if (label
!= olabel
3997 && (note
= find_reg_note (insn
, REG_LABEL
, olabel
)) != 0)
3998 XEXP (note
, 0) = label
;
4000 /* Otherwise, add a REG_LABEL note for LABEL unless there already
4002 else if (! find_reg_note (insn
, REG_LABEL
, label
))
4004 /* This code used to ignore labels which refered to dispatch
4005 tables to avoid flow.c generating worse code.
4007 However, in the presense of global optimizations like
4008 gcse which call find_basic_blocks without calling
4009 life_analysis, not recording such labels will lead
4010 to compiler aborts because of inconsistencies in the
4011 flow graph. So we go ahead and record the label.
4013 It may also be the case that the optimization argument
4014 is no longer valid because of the more accurate cfg
4015 we build in find_basic_blocks -- it no longer pessimizes
4016 code when it finds a REG_LABEL note. */
4017 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_LABEL
, label
,
4024 /* Do walk the labels in a vector, but not the first operand of an
4025 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
4028 if (! INSN_DELETED_P (insn
))
4030 int eltnum
= code
== ADDR_DIFF_VEC
? 1 : 0;
4032 for (i
= 0; i
< XVECLEN (x
, eltnum
); i
++)
4033 mark_jump_label (XVECEXP (x
, eltnum
, i
), NULL_RTX
, cross_jump
);
4041 fmt
= GET_RTX_FORMAT (code
);
4042 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4045 mark_jump_label (XEXP (x
, i
), insn
, cross_jump
);
4046 else if (fmt
[i
] == 'E')
4049 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4050 mark_jump_label (XVECEXP (x
, i
, j
), insn
, cross_jump
);
4055 /* If all INSN does is set the pc, delete it,
4056 and delete the insn that set the condition codes for it
4057 if that's what the previous thing was. */
4063 register rtx set
= single_set (insn
);
4065 if (set
&& GET_CODE (SET_DEST (set
)) == PC
)
4066 delete_computation (insn
);
4069 /* Verify INSN is a BARRIER and delete it. */
4072 delete_barrier (insn
)
4075 if (GET_CODE (insn
) != BARRIER
)
4081 /* Recursively delete prior insns that compute the value (used only by INSN
4082 which the caller is deleting) stored in the register mentioned by NOTE
4083 which is a REG_DEAD note associated with INSN. */
4086 delete_prior_computation (note
, insn
)
4091 rtx reg
= XEXP (note
, 0);
4093 for (our_prev
= prev_nonnote_insn (insn
);
4094 our_prev
&& (GET_CODE (our_prev
) == INSN
4095 || GET_CODE (our_prev
) == CALL_INSN
);
4096 our_prev
= prev_nonnote_insn (our_prev
))
4098 rtx pat
= PATTERN (our_prev
);
4100 /* If we reach a CALL which is not calling a const function
4101 or the callee pops the arguments, then give up. */
4102 if (GET_CODE (our_prev
) == CALL_INSN
4103 && (! CONST_CALL_P (our_prev
)
4104 || GET_CODE (pat
) != SET
|| GET_CODE (SET_SRC (pat
)) != CALL
))
4107 /* If we reach a SEQUENCE, it is too complex to try to
4108 do anything with it, so give up. */
4109 if (GET_CODE (pat
) == SEQUENCE
)
4112 if (GET_CODE (pat
) == USE
4113 && GET_CODE (XEXP (pat
, 0)) == INSN
)
4114 /* reorg creates USEs that look like this. We leave them
4115 alone because reorg needs them for its own purposes. */
4118 if (reg_set_p (reg
, pat
))
4120 if (side_effects_p (pat
) && GET_CODE (our_prev
) != CALL_INSN
)
4123 if (GET_CODE (pat
) == PARALLEL
)
4125 /* If we find a SET of something else, we can't
4130 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
4132 rtx part
= XVECEXP (pat
, 0, i
);
4134 if (GET_CODE (part
) == SET
4135 && SET_DEST (part
) != reg
)
4139 if (i
== XVECLEN (pat
, 0))
4140 delete_computation (our_prev
);
4142 else if (GET_CODE (pat
) == SET
4143 && GET_CODE (SET_DEST (pat
)) == REG
)
4145 int dest_regno
= REGNO (SET_DEST (pat
));
4147 = dest_regno
+ (dest_regno
< FIRST_PSEUDO_REGISTER
4148 ? HARD_REGNO_NREGS (dest_regno
,
4149 GET_MODE (SET_DEST (pat
))) : 1);
4150 int regno
= REGNO (reg
);
4151 int endregno
= regno
+ (regno
< FIRST_PSEUDO_REGISTER
4152 ? HARD_REGNO_NREGS (regno
, GET_MODE (reg
)) : 1);
4154 if (dest_regno
>= regno
4155 && dest_endregno
<= endregno
)
4156 delete_computation (our_prev
);
4158 /* We may have a multi-word hard register and some, but not
4159 all, of the words of the register are needed in subsequent
4160 insns. Write REG_UNUSED notes for those parts that were not
4162 else if (dest_regno
<= regno
4163 && dest_endregno
>= endregno
)
4167 REG_NOTES (our_prev
)
4168 = gen_rtx_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (our_prev
));
4170 for (i
= dest_regno
; i
< dest_endregno
; i
++)
4171 if (! find_regno_note (our_prev
, REG_UNUSED
, i
))
4174 if (i
== dest_endregno
)
4175 delete_computation (our_prev
);
4182 /* If PAT references the register that dies here, it is an
4183 additional use. Hence any prior SET isn't dead. However, this
4184 insn becomes the new place for the REG_DEAD note. */
4185 if (reg_overlap_mentioned_p (reg
, pat
))
4187 XEXP (note
, 1) = REG_NOTES (our_prev
);
4188 REG_NOTES (our_prev
) = note
;
4194 /* Delete INSN and recursively delete insns that compute values used only
4195 by INSN. This uses the REG_DEAD notes computed during flow analysis.
4196 If we are running before flow.c, we need do nothing since flow.c will
4197 delete dead code. We also can't know if the registers being used are
4198 dead or not at this point.
4200 Otherwise, look at all our REG_DEAD notes. If a previous insn does
4201 nothing other than set a register that dies in this insn, we can delete
4204 On machines with CC0, if CC0 is used in this insn, we may be able to
4205 delete the insn that set it. */
4208 delete_computation (insn
)
4215 if (reg_referenced_p (cc0_rtx
, PATTERN (insn
)))
4217 rtx prev
= prev_nonnote_insn (insn
);
4218 /* We assume that at this stage
4219 CC's are always set explicitly
4220 and always immediately before the jump that
4221 will use them. So if the previous insn
4222 exists to set the CC's, delete it
4223 (unless it performs auto-increments, etc.). */
4224 if (prev
&& GET_CODE (prev
) == INSN
4225 && sets_cc0_p (PATTERN (prev
)))
4227 if (sets_cc0_p (PATTERN (prev
)) > 0
4228 && ! side_effects_p (PATTERN (prev
)))
4229 delete_computation (prev
);
4231 /* Otherwise, show that cc0 won't be used. */
4232 REG_NOTES (prev
) = gen_rtx_EXPR_LIST (REG_UNUSED
,
4233 cc0_rtx
, REG_NOTES (prev
));
4238 #ifdef INSN_SCHEDULING
4239 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
4240 reload has completed. The schedulers need to be fixed. Until
4241 they are, we must not rely on the death notes here. */
4242 if (reload_completed
&& flag_schedule_insns_after_reload
)
4249 /* The REG_DEAD note may have been omitted for a register
4250 which is both set and used by the insn. */
4251 set
= single_set (insn
);
4252 if (set
&& GET_CODE (SET_DEST (set
)) == REG
)
4254 int dest_regno
= REGNO (SET_DEST (set
));
4256 = dest_regno
+ (dest_regno
< FIRST_PSEUDO_REGISTER
4257 ? HARD_REGNO_NREGS (dest_regno
,
4258 GET_MODE (SET_DEST (set
))) : 1);
4261 for (i
= dest_regno
; i
< dest_endregno
; i
++)
4263 if (! refers_to_regno_p (i
, i
+ 1, SET_SRC (set
), NULL_PTR
)
4264 || find_regno_note (insn
, REG_DEAD
, i
))
4267 note
= gen_rtx_EXPR_LIST (REG_DEAD
, (i
< FIRST_PSEUDO_REGISTER
4268 ? gen_rtx_REG (reg_raw_mode
[i
], i
)
4269 : SET_DEST (set
)), NULL_RTX
);
4270 delete_prior_computation (note
, insn
);
4274 for (note
= REG_NOTES (insn
); note
; note
= next
)
4276 next
= XEXP (note
, 1);
4278 if (REG_NOTE_KIND (note
) != REG_DEAD
4279 /* Verify that the REG_NOTE is legitimate. */
4280 || GET_CODE (XEXP (note
, 0)) != REG
)
4283 delete_prior_computation (note
, insn
);
4289 /* Delete insn INSN from the chain of insns and update label ref counts.
4290 May delete some following insns as a consequence; may even delete
4291 a label elsewhere and insns that follow it.
4293 Returns the first insn after INSN that was not deleted. */
4299 register rtx next
= NEXT_INSN (insn
);
4300 register rtx prev
= PREV_INSN (insn
);
4301 register int was_code_label
= (GET_CODE (insn
) == CODE_LABEL
);
4302 register int dont_really_delete
= 0;
4304 while (next
&& INSN_DELETED_P (next
))
4305 next
= NEXT_INSN (next
);
4307 /* This insn is already deleted => return first following nondeleted. */
4308 if (INSN_DELETED_P (insn
))
4312 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
4314 /* Don't delete user-declared labels. Convert them to special NOTEs
4316 if (was_code_label
&& LABEL_NAME (insn
) != 0
4317 && optimize
&& ! dont_really_delete
)
4319 PUT_CODE (insn
, NOTE
);
4320 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED_LABEL
;
4321 NOTE_SOURCE_FILE (insn
) = 0;
4322 dont_really_delete
= 1;
4325 /* Mark this insn as deleted. */
4326 INSN_DELETED_P (insn
) = 1;
4328 /* If this is an unconditional jump, delete it from the jump chain. */
4329 if (simplejump_p (insn
))
4330 delete_from_jump_chain (insn
);
4332 /* If instruction is followed by a barrier,
4333 delete the barrier too. */
4335 if (next
!= 0 && GET_CODE (next
) == BARRIER
)
4337 INSN_DELETED_P (next
) = 1;
4338 next
= NEXT_INSN (next
);
4341 /* Patch out INSN (and the barrier if any) */
4343 if (optimize
&& ! dont_really_delete
)
4347 NEXT_INSN (prev
) = next
;
4348 if (GET_CODE (prev
) == INSN
&& GET_CODE (PATTERN (prev
)) == SEQUENCE
)
4349 NEXT_INSN (XVECEXP (PATTERN (prev
), 0,
4350 XVECLEN (PATTERN (prev
), 0) - 1)) = next
;
4355 PREV_INSN (next
) = prev
;
4356 if (GET_CODE (next
) == INSN
&& GET_CODE (PATTERN (next
)) == SEQUENCE
)
4357 PREV_INSN (XVECEXP (PATTERN (next
), 0, 0)) = prev
;
4360 if (prev
&& NEXT_INSN (prev
) == 0)
4361 set_last_insn (prev
);
4364 /* If deleting a jump, decrement the count of the label,
4365 and delete the label if it is now unused. */
4367 if (GET_CODE (insn
) == JUMP_INSN
&& JUMP_LABEL (insn
))
4369 rtx lab
= JUMP_LABEL (insn
), lab_next
;
4371 if (--LABEL_NUSES (lab
) == 0)
4373 /* This can delete NEXT or PREV,
4374 either directly if NEXT is JUMP_LABEL (INSN),
4375 or indirectly through more levels of jumps. */
4378 /* I feel a little doubtful about this loop,
4379 but I see no clean and sure alternative way
4380 to find the first insn after INSN that is not now deleted.
4381 I hope this works. */
4382 while (next
&& INSN_DELETED_P (next
))
4383 next
= NEXT_INSN (next
);
4386 else if ((lab_next
= next_nonnote_insn (lab
)) != NULL
4387 && GET_CODE (lab_next
) == JUMP_INSN
4388 && (GET_CODE (PATTERN (lab_next
)) == ADDR_VEC
4389 || GET_CODE (PATTERN (lab_next
)) == ADDR_DIFF_VEC
))
4391 /* If we're deleting the tablejump, delete the dispatch table.
4392 We may not be able to kill the label immediately preceeding
4393 just yet, as it might be referenced in code leading up to
4395 delete_insn (lab_next
);
4399 /* Likewise if we're deleting a dispatch table. */
4401 if (GET_CODE (insn
) == JUMP_INSN
4402 && (GET_CODE (PATTERN (insn
)) == ADDR_VEC
4403 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
))
4405 rtx pat
= PATTERN (insn
);
4406 int i
, diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
4407 int len
= XVECLEN (pat
, diff_vec_p
);
4409 for (i
= 0; i
< len
; i
++)
4410 if (--LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)) == 0)
4411 delete_insn (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0));
4412 while (next
&& INSN_DELETED_P (next
))
4413 next
= NEXT_INSN (next
);
4417 while (prev
&& (INSN_DELETED_P (prev
) || GET_CODE (prev
) == NOTE
))
4418 prev
= PREV_INSN (prev
);
4420 /* If INSN was a label and a dispatch table follows it,
4421 delete the dispatch table. The tablejump must have gone already.
4422 It isn't useful to fall through into a table. */
4425 && NEXT_INSN (insn
) != 0
4426 && GET_CODE (NEXT_INSN (insn
)) == JUMP_INSN
4427 && (GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_VEC
4428 || GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_DIFF_VEC
))
4429 next
= delete_insn (NEXT_INSN (insn
));
4431 /* If INSN was a label, delete insns following it if now unreachable. */
4433 if (was_code_label
&& prev
&& GET_CODE (prev
) == BARRIER
)
4435 register RTX_CODE code
;
4437 && (GET_RTX_CLASS (code
= GET_CODE (next
)) == 'i'
4438 || code
== NOTE
|| code
== BARRIER
4439 || (code
== CODE_LABEL
&& INSN_DELETED_P (next
))))
4442 && NOTE_LINE_NUMBER (next
) != NOTE_INSN_FUNCTION_END
)
4443 next
= NEXT_INSN (next
);
4444 /* Keep going past other deleted labels to delete what follows. */
4445 else if (code
== CODE_LABEL
&& INSN_DELETED_P (next
))
4446 next
= NEXT_INSN (next
);
4448 /* Note: if this deletes a jump, it can cause more
4449 deletion of unreachable code, after a different label.
4450 As long as the value from this recursive call is correct,
4451 this invocation functions correctly. */
4452 next
= delete_insn (next
);
4459 /* Advance from INSN till reaching something not deleted
4460 then return that. May return INSN itself. */
4463 next_nondeleted_insn (insn
)
4466 while (INSN_DELETED_P (insn
))
4467 insn
= NEXT_INSN (insn
);
4471 /* Delete a range of insns from FROM to TO, inclusive.
4472 This is for the sake of peephole optimization, so assume
4473 that whatever these insns do will still be done by a new
4474 peephole insn that will replace them. */
4477 delete_for_peephole (from
, to
)
4478 register rtx from
, to
;
4480 register rtx insn
= from
;
4484 register rtx next
= NEXT_INSN (insn
);
4485 register rtx prev
= PREV_INSN (insn
);
4487 if (GET_CODE (insn
) != NOTE
)
4489 INSN_DELETED_P (insn
) = 1;
4491 /* Patch this insn out of the chain. */
4492 /* We don't do this all at once, because we
4493 must preserve all NOTEs. */
4495 NEXT_INSN (prev
) = next
;
4498 PREV_INSN (next
) = prev
;
4506 /* Note that if TO is an unconditional jump
4507 we *do not* delete the BARRIER that follows,
4508 since the peephole that replaces this sequence
4509 is also an unconditional jump in that case. */
4512 /* We have determined that INSN is never reached, and are about to
4513 delete it. Print a warning if the user asked for one.
4515 To try to make this warning more useful, this should only be called
4516 once per basic block not reached, and it only warns when the basic
4517 block contains more than one line from the current function, and
4518 contains at least one operation. CSE and inlining can duplicate insns,
4519 so it's possible to get spurious warnings from this. */
4522 never_reached_warning (avoided_insn
)
4526 rtx a_line_note
= NULL
;
4527 int two_avoided_lines
= 0;
4528 int contains_insn
= 0;
4530 if (! warn_notreached
)
4533 /* Scan forwards, looking at LINE_NUMBER notes, until
4534 we hit a LABEL or we run out of insns. */
4536 for (insn
= avoided_insn
; insn
!= NULL
; insn
= NEXT_INSN (insn
))
4538 if (GET_CODE (insn
) == CODE_LABEL
)
4540 else if (GET_CODE (insn
) == NOTE
/* A line number note? */
4541 && NOTE_LINE_NUMBER (insn
) >= 0)
4543 if (a_line_note
== NULL
)
4546 two_avoided_lines
|= (NOTE_LINE_NUMBER (a_line_note
)
4547 != NOTE_LINE_NUMBER (insn
));
4549 else if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
4552 if (two_avoided_lines
&& contains_insn
)
4553 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note
),
4554 NOTE_LINE_NUMBER (a_line_note
),
4555 "will never be executed");
4558 /* Invert the condition of the jump JUMP, and make it jump
4559 to label NLABEL instead of where it jumps now. */
4562 invert_jump (jump
, nlabel
)
4565 /* We have to either invert the condition and change the label or
4566 do neither. Either operation could fail. We first try to invert
4567 the jump. If that succeeds, we try changing the label. If that fails,
4568 we invert the jump back to what it was. */
4570 if (! invert_exp (PATTERN (jump
), jump
))
4573 if (redirect_jump (jump
, nlabel
))
4575 if (flag_branch_probabilities
)
4577 rtx note
= find_reg_note (jump
, REG_BR_PROB
, 0);
4579 /* An inverted jump means that a probability taken becomes a
4580 probability not taken. Subtract the branch probability from the
4581 probability base to convert it back to a taken probability.
4582 (We don't flip the probability on a branch that's never taken. */
4583 if (note
&& XINT (XEXP (note
, 0), 0) >= 0)
4584 XINT (XEXP (note
, 0), 0) = REG_BR_PROB_BASE
- XINT (XEXP (note
, 0), 0);
4590 if (! invert_exp (PATTERN (jump
), jump
))
4591 /* This should just be putting it back the way it was. */
4597 /* Invert the jump condition of rtx X contained in jump insn, INSN.
4599 Return 1 if we can do so, 0 if we cannot find a way to do so that
4600 matches a pattern. */
4603 invert_exp (x
, insn
)
4607 register RTX_CODE code
;
4609 register const char *fmt
;
4611 code
= GET_CODE (x
);
4613 if (code
== IF_THEN_ELSE
)
4615 register rtx comp
= XEXP (x
, 0);
4618 /* We can do this in two ways: The preferable way, which can only
4619 be done if this is not an integer comparison, is to reverse
4620 the comparison code. Otherwise, swap the THEN-part and ELSE-part
4621 of the IF_THEN_ELSE. If we can't do either, fail. */
4623 if (can_reverse_comparison_p (comp
, insn
)
4624 && validate_change (insn
, &XEXP (x
, 0),
4625 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp
)),
4626 GET_MODE (comp
), XEXP (comp
, 0),
4627 XEXP (comp
, 1)), 0))
4631 validate_change (insn
, &XEXP (x
, 1), XEXP (x
, 2), 1);
4632 validate_change (insn
, &XEXP (x
, 2), tem
, 1);
4633 return apply_change_group ();
4636 fmt
= GET_RTX_FORMAT (code
);
4637 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4640 if (! invert_exp (XEXP (x
, i
), insn
))
4645 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4646 if (!invert_exp (XVECEXP (x
, i
, j
), insn
))
4654 /* Make jump JUMP jump to label NLABEL instead of where it jumps now.
4655 If the old jump target label is unused as a result,
4656 it and the code following it may be deleted.
4658 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
4661 The return value will be 1 if the change was made, 0 if it wasn't (this
4662 can only occur for NLABEL == 0). */
4665 redirect_jump (jump
, nlabel
)
4668 register rtx olabel
= JUMP_LABEL (jump
);
4670 if (nlabel
== olabel
)
4673 if (! redirect_exp (&PATTERN (jump
), olabel
, nlabel
, jump
))
4676 /* If this is an unconditional branch, delete it from the jump_chain of
4677 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
4678 have UID's in range and JUMP_CHAIN is valid). */
4679 if (jump_chain
&& (simplejump_p (jump
)
4680 || GET_CODE (PATTERN (jump
)) == RETURN
))
4682 int label_index
= nlabel
? INSN_UID (nlabel
) : 0;
4684 delete_from_jump_chain (jump
);
4685 if (label_index
< max_jump_chain
4686 && INSN_UID (jump
) < max_jump_chain
)
4688 jump_chain
[INSN_UID (jump
)] = jump_chain
[label_index
];
4689 jump_chain
[label_index
] = jump
;
4693 JUMP_LABEL (jump
) = nlabel
;
4695 ++LABEL_NUSES (nlabel
);
4697 if (olabel
&& --LABEL_NUSES (olabel
) == 0)
4698 delete_insn (olabel
);
4703 /* Delete the instruction JUMP from any jump chain it might be on. */
4706 delete_from_jump_chain (jump
)
4710 rtx olabel
= JUMP_LABEL (jump
);
4712 /* Handle unconditional jumps. */
4713 if (jump_chain
&& olabel
!= 0
4714 && INSN_UID (olabel
) < max_jump_chain
4715 && simplejump_p (jump
))
4716 index
= INSN_UID (olabel
);
4717 /* Handle return insns. */
4718 else if (jump_chain
&& GET_CODE (PATTERN (jump
)) == RETURN
)
4722 if (jump_chain
[index
] == jump
)
4723 jump_chain
[index
] = jump_chain
[INSN_UID (jump
)];
4728 for (insn
= jump_chain
[index
];
4730 insn
= jump_chain
[INSN_UID (insn
)])
4731 if (jump_chain
[INSN_UID (insn
)] == jump
)
4733 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (jump
)];
4739 /* If NLABEL is nonzero, throughout the rtx at LOC,
4740 alter (LABEL_REF OLABEL) to (LABEL_REF NLABEL). If OLABEL is
4741 zero, alter (RETURN) to (LABEL_REF NLABEL).
4743 If NLABEL is zero, alter (LABEL_REF OLABEL) to (RETURN) and check
4744 validity with validate_change. Convert (set (pc) (label_ref olabel))
4747 Return 0 if we found a change we would like to make but it is invalid.
4748 Otherwise, return 1. */
4751 redirect_exp (loc
, olabel
, nlabel
, insn
)
4756 register rtx x
= *loc
;
4757 register RTX_CODE code
= GET_CODE (x
);
4759 register const char *fmt
;
4761 if (code
== LABEL_REF
)
4763 if (XEXP (x
, 0) == olabel
)
4766 XEXP (x
, 0) = nlabel
;
4768 return validate_change (insn
, loc
, gen_rtx_RETURN (VOIDmode
), 0);
4772 else if (code
== RETURN
&& olabel
== 0)
4774 x
= gen_rtx_LABEL_REF (VOIDmode
, nlabel
);
4775 if (loc
== &PATTERN (insn
))
4776 x
= gen_rtx_SET (VOIDmode
, pc_rtx
, x
);
4777 return validate_change (insn
, loc
, x
, 0);
4780 if (code
== SET
&& nlabel
== 0 && SET_DEST (x
) == pc_rtx
4781 && GET_CODE (SET_SRC (x
)) == LABEL_REF
4782 && XEXP (SET_SRC (x
), 0) == olabel
)
4783 return validate_change (insn
, loc
, gen_rtx_RETURN (VOIDmode
), 0);
4785 fmt
= GET_RTX_FORMAT (code
);
4786 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4789 if (! redirect_exp (&XEXP (x
, i
), olabel
, nlabel
, insn
))
4794 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4795 if (! redirect_exp (&XVECEXP (x
, i
, j
), olabel
, nlabel
, insn
))
4803 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
4805 If the old jump target label (before the dispatch table) becomes unused,
4806 it and the dispatch table may be deleted. In that case, find the insn
4807 before the jump references that label and delete it and logical successors
4811 redirect_tablejump (jump
, nlabel
)
4814 register rtx olabel
= JUMP_LABEL (jump
);
4816 /* Add this jump to the jump_chain of NLABEL. */
4817 if (jump_chain
&& INSN_UID (nlabel
) < max_jump_chain
4818 && INSN_UID (jump
) < max_jump_chain
)
4820 jump_chain
[INSN_UID (jump
)] = jump_chain
[INSN_UID (nlabel
)];
4821 jump_chain
[INSN_UID (nlabel
)] = jump
;
4824 PATTERN (jump
) = gen_jump (nlabel
);
4825 JUMP_LABEL (jump
) = nlabel
;
4826 ++LABEL_NUSES (nlabel
);
4827 INSN_CODE (jump
) = -1;
4829 if (--LABEL_NUSES (olabel
) == 0)
4831 delete_labelref_insn (jump
, olabel
, 0);
4832 delete_insn (olabel
);
4836 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
4837 If we found one, delete it and then delete this insn if DELETE_THIS is
4838 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
4841 delete_labelref_insn (insn
, label
, delete_this
)
4848 if (GET_CODE (insn
) != NOTE
4849 && reg_mentioned_p (label
, PATTERN (insn
)))
4860 for (link
= LOG_LINKS (insn
); link
; link
= XEXP (link
, 1))
4861 if (delete_labelref_insn (XEXP (link
, 0), label
, 1))
4875 /* Like rtx_equal_p except that it considers two REGs as equal
4876 if they renumber to the same value and considers two commutative
4877 operations to be the same if the order of the operands has been
4880 ??? Addition is not commutative on the PA due to the weird implicit
4881 space register selection rules for memory addresses. Therefore, we
4882 don't consider a + b == b + a.
4884 We could/should make this test a little tighter. Possibly only
4885 disabling it on the PA via some backend macro or only disabling this
4886 case when the PLUS is inside a MEM. */
4889 rtx_renumbered_equal_p (x
, y
)
4893 register RTX_CODE code
= GET_CODE (x
);
4894 register const char *fmt
;
4899 if ((code
== REG
|| (code
== SUBREG
&& GET_CODE (SUBREG_REG (x
)) == REG
))
4900 && (GET_CODE (y
) == REG
|| (GET_CODE (y
) == SUBREG
4901 && GET_CODE (SUBREG_REG (y
)) == REG
)))
4903 int reg_x
= -1, reg_y
= -1;
4904 int word_x
= 0, word_y
= 0;
4906 if (GET_MODE (x
) != GET_MODE (y
))
4909 /* If we haven't done any renumbering, don't
4910 make any assumptions. */
4911 if (reg_renumber
== 0)
4912 return rtx_equal_p (x
, y
);
4916 reg_x
= REGNO (SUBREG_REG (x
));
4917 word_x
= SUBREG_WORD (x
);
4919 if (reg_renumber
[reg_x
] >= 0)
4921 reg_x
= reg_renumber
[reg_x
] + word_x
;
4929 if (reg_renumber
[reg_x
] >= 0)
4930 reg_x
= reg_renumber
[reg_x
];
4933 if (GET_CODE (y
) == SUBREG
)
4935 reg_y
= REGNO (SUBREG_REG (y
));
4936 word_y
= SUBREG_WORD (y
);
4938 if (reg_renumber
[reg_y
] >= 0)
4940 reg_y
= reg_renumber
[reg_y
];
4948 if (reg_renumber
[reg_y
] >= 0)
4949 reg_y
= reg_renumber
[reg_y
];
4952 return reg_x
>= 0 && reg_x
== reg_y
&& word_x
== word_y
;
4955 /* Now we have disposed of all the cases
4956 in which different rtx codes can match. */
4957 if (code
!= GET_CODE (y
))
4969 return INTVAL (x
) == INTVAL (y
);
4972 /* We can't assume nonlocal labels have their following insns yet. */
4973 if (LABEL_REF_NONLOCAL_P (x
) || LABEL_REF_NONLOCAL_P (y
))
4974 return XEXP (x
, 0) == XEXP (y
, 0);
4976 /* Two label-refs are equivalent if they point at labels
4977 in the same position in the instruction stream. */
4978 return (next_real_insn (XEXP (x
, 0))
4979 == next_real_insn (XEXP (y
, 0)));
4982 return XSTR (x
, 0) == XSTR (y
, 0);
4985 /* If we didn't match EQ equality above, they aren't the same. */
4992 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
4994 if (GET_MODE (x
) != GET_MODE (y
))
4997 /* For commutative operations, the RTX match if the operand match in any
4998 order. Also handle the simple binary and unary cases without a loop.
5000 ??? Don't consider PLUS a commutative operator; see comments above. */
5001 if ((code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
5003 return ((rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
5004 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)))
5005 || (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 1))
5006 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 0))));
5007 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
5008 return (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
5009 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)));
5010 else if (GET_RTX_CLASS (code
) == '1')
5011 return rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0));
5013 /* Compare the elements. If any pair of corresponding elements
5014 fail to match, return 0 for the whole things. */
5016 fmt
= GET_RTX_FORMAT (code
);
5017 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
5023 if (XWINT (x
, i
) != XWINT (y
, i
))
5028 if (XINT (x
, i
) != XINT (y
, i
))
5033 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
5038 if (! rtx_renumbered_equal_p (XEXP (x
, i
), XEXP (y
, i
)))
5043 if (XEXP (x
, i
) != XEXP (y
, i
))
5050 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
5052 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
5053 if (!rtx_renumbered_equal_p (XVECEXP (x
, i
, j
), XVECEXP (y
, i
, j
)))
5064 /* If X is a hard register or equivalent to one or a subregister of one,
5065 return the hard register number. If X is a pseudo register that was not
5066 assigned a hard register, return the pseudo register number. Otherwise,
5067 return -1. Any rtx is valid for X. */
5073 if (GET_CODE (x
) == REG
)
5075 if (REGNO (x
) >= FIRST_PSEUDO_REGISTER
&& reg_renumber
[REGNO (x
)] >= 0)
5076 return reg_renumber
[REGNO (x
)];
5079 if (GET_CODE (x
) == SUBREG
)
5081 int base
= true_regnum (SUBREG_REG (x
));
5082 if (base
>= 0 && base
< FIRST_PSEUDO_REGISTER
)
5083 return SUBREG_WORD (x
) + base
;
5088 /* Optimize code of the form:
5090 for (x = a[i]; x; ...)
5092 for (x = a[i]; x; ...)
5096 Loop optimize will change the above code into
5100 { ...; if (! (x = ...)) break; }
5103 { ...; if (! (x = ...)) break; }
5106 In general, if the first test fails, the program can branch
5107 directly to `foo' and skip the second try which is doomed to fail.
5108 We run this after loop optimization and before flow analysis. */
5110 /* When comparing the insn patterns, we track the fact that different
5111 pseudo-register numbers may have been used in each computation.
5112 The following array stores an equivalence -- same_regs[I] == J means
5113 that pseudo register I was used in the first set of tests in a context
5114 where J was used in the second set. We also count the number of such
5115 pending equivalences. If nonzero, the expressions really aren't the
5118 static int *same_regs
;
5120 static int num_same_regs
;
5122 /* Track any registers modified between the target of the first jump and
5123 the second jump. They never compare equal. */
5125 static char *modified_regs
;
5127 /* Record if memory was modified. */
5129 static int modified_mem
;
5131 /* Called via note_stores on each insn between the target of the first
5132 branch and the second branch. It marks any changed registers. */
5135 mark_modified_reg (dest
, x
, data
)
5137 rtx x ATTRIBUTE_UNUSED
;
5138 void *data ATTRIBUTE_UNUSED
;
5142 if (GET_CODE (dest
) == SUBREG
)
5143 dest
= SUBREG_REG (dest
);
5145 if (GET_CODE (dest
) == MEM
)
5148 if (GET_CODE (dest
) != REG
)
5151 regno
= REGNO (dest
);
5152 if (regno
>= FIRST_PSEUDO_REGISTER
)
5153 modified_regs
[regno
] = 1;
5155 for (i
= 0; i
< HARD_REGNO_NREGS (regno
, GET_MODE (dest
)); i
++)
5156 modified_regs
[regno
+ i
] = 1;
5159 /* F is the first insn in the chain of insns. */
5162 thread_jumps (f
, max_reg
, flag_before_loop
)
5165 int flag_before_loop
;
5167 /* Basic algorithm is to find a conditional branch,
5168 the label it may branch to, and the branch after
5169 that label. If the two branches test the same condition,
5170 walk back from both branch paths until the insn patterns
5171 differ, or code labels are hit. If we make it back to
5172 the target of the first branch, then we know that the first branch
5173 will either always succeed or always fail depending on the relative
5174 senses of the two branches. So adjust the first branch accordingly
5177 rtx label
, b1
, b2
, t1
, t2
;
5178 enum rtx_code code1
, code2
;
5179 rtx b1op0
, b1op1
, b2op0
, b2op1
;
5184 /* Allocate register tables and quick-reset table. */
5185 modified_regs
= (char *) alloca (max_reg
* sizeof (char));
5186 same_regs
= (int *) alloca (max_reg
* sizeof (int));
5187 all_reset
= (int *) alloca (max_reg
* sizeof (int));
5188 for (i
= 0; i
< max_reg
; i
++)
5195 for (b1
= f
; b1
; b1
= NEXT_INSN (b1
))
5197 /* Get to a candidate branch insn. */
5198 if (GET_CODE (b1
) != JUMP_INSN
5199 || ! condjump_p (b1
) || simplejump_p (b1
)
5200 || JUMP_LABEL (b1
) == 0)
5203 bzero (modified_regs
, max_reg
* sizeof (char));
5206 bcopy ((char *) all_reset
, (char *) same_regs
,
5207 max_reg
* sizeof (int));
5210 label
= JUMP_LABEL (b1
);
5212 /* Look for a branch after the target. Record any registers and
5213 memory modified between the target and the branch. Stop when we
5214 get to a label since we can't know what was changed there. */
5215 for (b2
= NEXT_INSN (label
); b2
; b2
= NEXT_INSN (b2
))
5217 if (GET_CODE (b2
) == CODE_LABEL
)
5220 else if (GET_CODE (b2
) == JUMP_INSN
)
5222 /* If this is an unconditional jump and is the only use of
5223 its target label, we can follow it. */
5224 if (simplejump_p (b2
)
5225 && JUMP_LABEL (b2
) != 0
5226 && LABEL_NUSES (JUMP_LABEL (b2
)) == 1)
5228 b2
= JUMP_LABEL (b2
);
5235 if (GET_CODE (b2
) != CALL_INSN
&& GET_CODE (b2
) != INSN
)
5238 if (GET_CODE (b2
) == CALL_INSN
)
5241 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
5242 if (call_used_regs
[i
] && ! fixed_regs
[i
]
5243 && i
!= STACK_POINTER_REGNUM
5244 && i
!= FRAME_POINTER_REGNUM
5245 && i
!= HARD_FRAME_POINTER_REGNUM
5246 && i
!= ARG_POINTER_REGNUM
)
5247 modified_regs
[i
] = 1;
5250 note_stores (PATTERN (b2
), mark_modified_reg
, NULL
);
5253 /* Check the next candidate branch insn from the label
5256 || GET_CODE (b2
) != JUMP_INSN
5258 || ! condjump_p (b2
)
5259 || simplejump_p (b2
))
5262 /* Get the comparison codes and operands, reversing the
5263 codes if appropriate. If we don't have comparison codes,
5264 we can't do anything. */
5265 b1op0
= XEXP (XEXP (SET_SRC (PATTERN (b1
)), 0), 0);
5266 b1op1
= XEXP (XEXP (SET_SRC (PATTERN (b1
)), 0), 1);
5267 code1
= GET_CODE (XEXP (SET_SRC (PATTERN (b1
)), 0));
5268 if (XEXP (SET_SRC (PATTERN (b1
)), 1) == pc_rtx
)
5269 code1
= reverse_condition (code1
);
5271 b2op0
= XEXP (XEXP (SET_SRC (PATTERN (b2
)), 0), 0);
5272 b2op1
= XEXP (XEXP (SET_SRC (PATTERN (b2
)), 0), 1);
5273 code2
= GET_CODE (XEXP (SET_SRC (PATTERN (b2
)), 0));
5274 if (XEXP (SET_SRC (PATTERN (b2
)), 1) == pc_rtx
)
5275 code2
= reverse_condition (code2
);
5277 /* If they test the same things and knowing that B1 branches
5278 tells us whether or not B2 branches, check if we
5279 can thread the branch. */
5280 if (rtx_equal_for_thread_p (b1op0
, b2op0
, b2
)
5281 && rtx_equal_for_thread_p (b1op1
, b2op1
, b2
)
5282 && (comparison_dominates_p (code1
, code2
)
5283 || (comparison_dominates_p (code1
, reverse_condition (code2
))
5284 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1
)),
5288 t1
= prev_nonnote_insn (b1
);
5289 t2
= prev_nonnote_insn (b2
);
5291 while (t1
!= 0 && t2
!= 0)
5295 /* We have reached the target of the first branch.
5296 If there are no pending register equivalents,
5297 we know that this branch will either always
5298 succeed (if the senses of the two branches are
5299 the same) or always fail (if not). */
5302 if (num_same_regs
!= 0)
5305 if (comparison_dominates_p (code1
, code2
))
5306 new_label
= JUMP_LABEL (b2
);
5308 new_label
= get_label_after (b2
);
5310 if (JUMP_LABEL (b1
) != new_label
)
5312 rtx prev
= PREV_INSN (new_label
);
5314 if (flag_before_loop
5315 && GET_CODE (prev
) == NOTE
5316 && NOTE_LINE_NUMBER (prev
) == NOTE_INSN_LOOP_BEG
)
5318 /* Don't thread to the loop label. If a loop
5319 label is reused, loop optimization will
5320 be disabled for that loop. */
5321 new_label
= gen_label_rtx ();
5322 emit_label_after (new_label
, PREV_INSN (prev
));
5324 changed
|= redirect_jump (b1
, new_label
);
5329 /* If either of these is not a normal insn (it might be
5330 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
5331 have already been skipped above.) Similarly, fail
5332 if the insns are different. */
5333 if (GET_CODE (t1
) != INSN
|| GET_CODE (t2
) != INSN
5334 || recog_memoized (t1
) != recog_memoized (t2
)
5335 || ! rtx_equal_for_thread_p (PATTERN (t1
),
5339 t1
= prev_nonnote_insn (t1
);
5340 t2
= prev_nonnote_insn (t2
);
5347 /* This is like RTX_EQUAL_P except that it knows about our handling of
5348 possibly equivalent registers and knows to consider volatile and
5349 modified objects as not equal.
5351 YINSN is the insn containing Y. */
5354 rtx_equal_for_thread_p (x
, y
, yinsn
)
5360 register enum rtx_code code
;
5361 register const char *fmt
;
5363 code
= GET_CODE (x
);
5364 /* Rtx's of different codes cannot be equal. */
5365 if (code
!= GET_CODE (y
))
5368 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
5369 (REG:SI x) and (REG:HI x) are NOT equivalent. */
5371 if (GET_MODE (x
) != GET_MODE (y
))
5374 /* For floating-point, consider everything unequal. This is a bit
5375 pessimistic, but this pass would only rarely do anything for FP
5377 if (TARGET_FLOAT_FORMAT
== IEEE_FLOAT_FORMAT
5378 && FLOAT_MODE_P (GET_MODE (x
)) && ! flag_fast_math
)
5381 /* For commutative operations, the RTX match if the operand match in any
5382 order. Also handle the simple binary and unary cases without a loop. */
5383 if (code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
5384 return ((rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
5385 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
))
5386 || (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 1), yinsn
)
5387 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 0), yinsn
)));
5388 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
5389 return (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
5390 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
));
5391 else if (GET_RTX_CLASS (code
) == '1')
5392 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
5394 /* Handle special-cases first. */
5398 if (REGNO (x
) == REGNO (y
) && ! modified_regs
[REGNO (x
)])
5401 /* If neither is user variable or hard register, check for possible
5403 if (REG_USERVAR_P (x
) || REG_USERVAR_P (y
)
5404 || REGNO (x
) < FIRST_PSEUDO_REGISTER
5405 || REGNO (y
) < FIRST_PSEUDO_REGISTER
)
5408 if (same_regs
[REGNO (x
)] == -1)
5410 same_regs
[REGNO (x
)] = REGNO (y
);
5413 /* If this is the first time we are seeing a register on the `Y'
5414 side, see if it is the last use. If not, we can't thread the
5415 jump, so mark it as not equivalent. */
5416 if (REGNO_LAST_UID (REGNO (y
)) != INSN_UID (yinsn
))
5422 return (same_regs
[REGNO (x
)] == REGNO (y
));
5427 /* If memory modified or either volatile, not equivalent.
5428 Else, check address. */
5429 if (modified_mem
|| MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
5432 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
5435 if (MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
5441 /* Cancel a pending `same_regs' if setting equivalenced registers.
5442 Then process source. */
5443 if (GET_CODE (SET_DEST (x
)) == REG
5444 && GET_CODE (SET_DEST (y
)) == REG
)
5446 if (same_regs
[REGNO (SET_DEST (x
))] == REGNO (SET_DEST (y
)))
5448 same_regs
[REGNO (SET_DEST (x
))] = -1;
5451 else if (REGNO (SET_DEST (x
)) != REGNO (SET_DEST (y
)))
5455 if (rtx_equal_for_thread_p (SET_DEST (x
), SET_DEST (y
), yinsn
) == 0)
5458 return rtx_equal_for_thread_p (SET_SRC (x
), SET_SRC (y
), yinsn
);
5461 return XEXP (x
, 0) == XEXP (y
, 0);
5464 return XSTR (x
, 0) == XSTR (y
, 0);
5473 fmt
= GET_RTX_FORMAT (code
);
5474 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
5479 if (XWINT (x
, i
) != XWINT (y
, i
))
5485 if (XINT (x
, i
) != XINT (y
, i
))
5491 /* Two vectors must have the same length. */
5492 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
5495 /* And the corresponding elements must match. */
5496 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
5497 if (rtx_equal_for_thread_p (XVECEXP (x
, i
, j
),
5498 XVECEXP (y
, i
, j
), yinsn
) == 0)
5503 if (rtx_equal_for_thread_p (XEXP (x
, i
), XEXP (y
, i
), yinsn
) == 0)
5509 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
5514 /* These are just backpointers, so they don't matter. */
5521 /* It is believed that rtx's at this level will never
5522 contain anything but integers and other rtx's,
5523 except for within LABEL_REFs and SYMBOL_REFs. */
5532 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
5533 /* Return the insn that NEW can be safely inserted in front of starting at
5534 the jump insn INSN. Return 0 if it is not safe to do this jump
5535 optimization. Note that NEW must contain a single set. */
5538 find_insert_position (insn
, new)
5545 /* If NEW does not clobber, it is safe to insert NEW before INSN. */
5546 if (GET_CODE (PATTERN (new)) != PARALLEL
)
5549 for (i
= XVECLEN (PATTERN (new), 0) - 1; i
>= 0; i
--)
5550 if (GET_CODE (XVECEXP (PATTERN (new), 0, i
)) == CLOBBER
5551 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i
), 0),
5558 /* There is a good chance that the previous insn PREV sets the thing
5559 being clobbered (often the CC in a hard reg). If PREV does not
5560 use what NEW sets, we can insert NEW before PREV. */
5562 prev
= prev_active_insn (insn
);
5563 for (i
= XVECLEN (PATTERN (new), 0) - 1; i
>= 0; i
--)
5564 if (GET_CODE (XVECEXP (PATTERN (new), 0, i
)) == CLOBBER
5565 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i
), 0),
5567 && ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i
), 0),
5571 return reg_mentioned_p (SET_DEST (single_set (new)), prev
) ? 0 : prev
;
5573 #endif /* !HAVE_cc0 */