1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 88, 89, 91-99, 2000 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
PARAMS ((rtx
));
111 static void delete_barrier_successors
PARAMS ((rtx
));
112 static void mark_all_labels
PARAMS ((rtx
, int));
113 static rtx delete_unreferenced_labels
PARAMS ((rtx
));
114 static void delete_noop_moves
PARAMS ((rtx
));
115 static int calculate_can_reach_end
PARAMS ((rtx
, int));
116 static int duplicate_loop_exit_test
PARAMS ((rtx
));
117 static void find_cross_jump
PARAMS ((rtx
, rtx
, int, rtx
*, rtx
*));
118 static void do_cross_jump
PARAMS ((rtx
, rtx
, rtx
));
119 static int jump_back_p
PARAMS ((rtx
, rtx
));
120 static int tension_vector_labels
PARAMS ((rtx
, int));
121 static void mark_jump_label
PARAMS ((rtx
, rtx
, int));
122 static void delete_computation
PARAMS ((rtx
));
123 static void delete_from_jump_chain
PARAMS ((rtx
));
124 static int delete_labelref_insn
PARAMS ((rtx
, rtx
, int));
125 static void mark_modified_reg
PARAMS ((rtx
, rtx
, void *));
126 static void redirect_tablejump
PARAMS ((rtx
, rtx
));
127 static void jump_optimize_1
PARAMS ((rtx
, int, int, int, int));
128 #if ! defined(HAVE_cc0) && ! defined(HAVE_conditional_arithmetic)
129 static rtx find_insert_position
PARAMS ((rtx
, rtx
));
131 static int returnjump_p_1
PARAMS ((rtx
*, void *));
132 static void delete_prior_computation
PARAMS ((rtx
, rtx
));
134 /* Main external entry point into the jump optimizer. See comments before
135 jump_optimize_1 for descriptions of the arguments. */
137 jump_optimize (f
, cross_jump
, noop_moves
, after_regscan
)
143 jump_optimize_1 (f
, cross_jump
, noop_moves
, after_regscan
, 0);
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
*) xcalloc (max_jump_chain
, sizeof (rtx
));
210 mark_all_labels (f
, cross_jump
);
212 /* Keep track of labels used from static data;
213 they cannot ever be deleted. */
215 for (insn
= forced_labels
; insn
; insn
= XEXP (insn
, 1))
216 LABEL_NUSES (XEXP (insn
, 0))++;
218 check_exception_handler_labels ();
220 /* Keep track of labels used for marking handlers for exception
221 regions; they cannot usually be deleted. */
223 for (insn
= exception_handler_labels
; insn
; insn
= XEXP (insn
, 1))
224 LABEL_NUSES (XEXP (insn
, 0))++;
226 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
227 notes and recompute LABEL_NUSES. */
228 if (mark_labels_only
)
231 exception_optimize ();
233 last_insn
= delete_unreferenced_labels (f
);
236 if (optimize
&& HAVE_return
)
238 /* If we fall through to the epilogue, see if we can insert a RETURN insn
239 in front of it. If the machine allows it at this point (we might be
240 after reload for a leaf routine), it will improve optimization for it
242 insn
= get_last_insn ();
243 while (insn
&& GET_CODE (insn
) == NOTE
)
244 insn
= PREV_INSN (insn
);
246 if (insn
&& GET_CODE (insn
) != BARRIER
)
248 emit_jump_insn (gen_return ());
255 delete_noop_moves (f
);
257 /* If we haven't yet gotten to reload and we have just run regscan,
258 delete any insn that sets a register that isn't used elsewhere.
259 This helps some of the optimizations below by having less insns
260 being jumped around. */
262 if (optimize
&& ! reload_completed
&& after_regscan
)
263 for (insn
= f
; insn
; insn
= next
)
265 rtx set
= single_set (insn
);
267 next
= NEXT_INSN (insn
);
269 if (set
&& GET_CODE (SET_DEST (set
)) == REG
270 && REGNO (SET_DEST (set
)) >= FIRST_PSEUDO_REGISTER
271 && REGNO_FIRST_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
272 /* We use regno_last_note_uid so as not to delete the setting
273 of a reg that's used in notes. A subsequent optimization
274 might arrange to use that reg for real. */
275 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
276 && ! side_effects_p (SET_SRC (set
))
277 && ! find_reg_note (insn
, REG_RETVAL
, 0)
278 /* An ADDRESSOF expression can turn into a use of the internal arg
279 pointer, so do not delete the initialization of the internal
280 arg pointer yet. If it is truly dead, flow will delete the
281 initializing insn. */
282 && SET_DEST (set
) != current_function_internal_arg_pointer
)
286 /* Now iterate optimizing jumps until nothing changes over one pass. */
288 old_max_reg
= max_reg_num ();
293 for (insn
= f
; insn
; insn
= next
)
296 rtx temp
, temp1
, temp2
= NULL_RTX
, temp3
, temp4
, temp5
, temp6
;
298 int this_is_simplejump
, this_is_condjump
, reversep
= 0;
299 int this_is_condjump_in_parallel
;
301 next
= NEXT_INSN (insn
);
303 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
304 jump. Try to optimize by duplicating the loop exit test if so.
305 This is only safe immediately after regscan, because it uses
306 the values of regno_first_uid and regno_last_uid. */
307 if (after_regscan
&& GET_CODE (insn
) == NOTE
308 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
309 && (temp1
= next_nonnote_insn (insn
)) != 0
310 && simplejump_p (temp1
))
312 temp
= PREV_INSN (insn
);
313 if (duplicate_loop_exit_test (insn
))
316 next
= NEXT_INSN (temp
);
321 if (GET_CODE (insn
) != JUMP_INSN
)
324 this_is_simplejump
= simplejump_p (insn
);
325 this_is_condjump
= condjump_p (insn
);
326 this_is_condjump_in_parallel
= condjump_in_parallel_p (insn
);
328 /* Tension the labels in dispatch tables. */
330 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
)
331 changed
|= tension_vector_labels (PATTERN (insn
), 0);
332 if (GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
333 changed
|= tension_vector_labels (PATTERN (insn
), 1);
335 /* See if this jump goes to another jump and redirect if so. */
336 nlabel
= follow_jumps (JUMP_LABEL (insn
));
337 if (nlabel
!= JUMP_LABEL (insn
))
338 changed
|= redirect_jump (insn
, nlabel
);
343 /* If a dispatch table always goes to the same place,
344 get rid of it and replace the insn that uses it. */
346 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
347 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
350 rtx pat
= PATTERN (insn
);
351 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
352 int len
= XVECLEN (pat
, diff_vec_p
);
353 rtx dispatch
= prev_real_insn (insn
);
356 for (i
= 0; i
< len
; i
++)
357 if (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)
358 != XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0))
363 && GET_CODE (dispatch
) == JUMP_INSN
364 && JUMP_LABEL (dispatch
) != 0
365 /* Don't mess with a casesi insn.
366 XXX according to the comment before computed_jump_p(),
367 all casesi insns should be a parallel of the jump
368 and a USE of a LABEL_REF. */
369 && ! ((set
= single_set (dispatch
)) != NULL
370 && (GET_CODE (SET_SRC (set
)) == IF_THEN_ELSE
))
371 && next_real_insn (JUMP_LABEL (dispatch
)) == insn
)
373 redirect_tablejump (dispatch
,
374 XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0));
379 /* If a jump references the end of the function, try to turn
380 it into a RETURN insn, possibly a conditional one. */
381 if (JUMP_LABEL (insn
) != 0
382 && (next_active_insn (JUMP_LABEL (insn
)) == 0
383 || GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn
))))
385 changed
|= redirect_jump (insn
, NULL_RTX
);
387 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
389 /* Detect jump to following insn. */
390 if (reallabelprev
== insn
&& this_is_condjump
)
392 next
= next_real_insn (JUMP_LABEL (insn
));
398 /* Detect a conditional jump going to the same place
399 as an immediately following unconditional jump. */
400 else if (this_is_condjump
401 && (temp
= next_active_insn (insn
)) != 0
402 && simplejump_p (temp
)
403 && (next_active_insn (JUMP_LABEL (insn
))
404 == next_active_insn (JUMP_LABEL (temp
))))
406 /* Don't mess up test coverage analysis. */
408 if (flag_test_coverage
&& !reload_completed
)
409 for (temp2
= insn
; temp2
!= temp
; temp2
= NEXT_INSN (temp2
))
410 if (GET_CODE (temp2
) == NOTE
&& NOTE_LINE_NUMBER (temp2
) > 0)
421 /* Detect a conditional jump jumping over an unconditional jump. */
423 else if ((this_is_condjump
|| this_is_condjump_in_parallel
)
424 && ! this_is_simplejump
425 && reallabelprev
!= 0
426 && GET_CODE (reallabelprev
) == JUMP_INSN
427 && prev_active_insn (reallabelprev
) == insn
428 && no_labels_between_p (insn
, reallabelprev
)
429 && simplejump_p (reallabelprev
))
431 /* When we invert the unconditional jump, we will be
432 decrementing the usage count of its old label.
433 Make sure that we don't delete it now because that
434 might cause the following code to be deleted. */
435 rtx prev_uses
= prev_nonnote_insn (reallabelprev
);
436 rtx prev_label
= JUMP_LABEL (insn
);
439 ++LABEL_NUSES (prev_label
);
441 if (invert_jump (insn
, JUMP_LABEL (reallabelprev
)))
443 /* It is very likely that if there are USE insns before
444 this jump, they hold REG_DEAD notes. These REG_DEAD
445 notes are no longer valid due to this optimization,
446 and will cause the life-analysis that following passes
447 (notably delayed-branch scheduling) to think that
448 these registers are dead when they are not.
450 To prevent this trouble, we just remove the USE insns
451 from the insn chain. */
453 while (prev_uses
&& GET_CODE (prev_uses
) == INSN
454 && GET_CODE (PATTERN (prev_uses
)) == USE
)
456 rtx useless
= prev_uses
;
457 prev_uses
= prev_nonnote_insn (prev_uses
);
458 delete_insn (useless
);
461 delete_insn (reallabelprev
);
465 /* We can now safely delete the label if it is unreferenced
466 since the delete_insn above has deleted the BARRIER. */
467 if (prev_label
&& --LABEL_NUSES (prev_label
) == 0)
468 delete_insn (prev_label
);
470 next
= NEXT_INSN (insn
);
473 /* If we have an unconditional jump preceded by a USE, try to put
474 the USE before the target and jump there. This simplifies many
475 of the optimizations below since we don't have to worry about
476 dealing with these USE insns. We only do this if the label
477 being branch to already has the identical USE or if code
478 never falls through to that label. */
480 else if (this_is_simplejump
481 && (temp
= prev_nonnote_insn (insn
)) != 0
482 && GET_CODE (temp
) == INSN
483 && GET_CODE (PATTERN (temp
)) == USE
484 && (temp1
= prev_nonnote_insn (JUMP_LABEL (insn
))) != 0
485 && (GET_CODE (temp1
) == BARRIER
486 || (GET_CODE (temp1
) == INSN
487 && rtx_equal_p (PATTERN (temp
), PATTERN (temp1
))))
488 /* Don't do this optimization if we have a loop containing
489 only the USE instruction, and the loop start label has
490 a usage count of 1. This is because we will redo this
491 optimization everytime through the outer loop, and jump
492 opt will never exit. */
493 && ! ((temp2
= prev_nonnote_insn (temp
)) != 0
494 && temp2
== JUMP_LABEL (insn
)
495 && LABEL_NUSES (temp2
) == 1))
497 if (GET_CODE (temp1
) == BARRIER
)
499 emit_insn_after (PATTERN (temp
), temp1
);
500 temp1
= NEXT_INSN (temp1
);
504 redirect_jump (insn
, get_label_before (temp1
));
505 reallabelprev
= prev_real_insn (temp1
);
507 next
= NEXT_INSN (insn
);
510 /* Simplify if (...) x = a; else x = b; by converting it
511 to x = b; if (...) x = a;
512 if B is sufficiently simple, the test doesn't involve X,
513 and nothing in the test modifies B or X.
515 If we have small register classes, we also can't do this if X
518 If the "x = b;" insn has any REG_NOTES, we don't do this because
519 of the possibility that we are running after CSE and there is a
520 REG_EQUAL note that is only valid if the branch has already been
521 taken. If we move the insn with the REG_EQUAL note, we may
522 fold the comparison to always be false in a later CSE pass.
523 (We could also delete the REG_NOTES when moving the insn, but it
524 seems simpler to not move it.) An exception is that we can move
525 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
526 value is the same as "b".
528 INSN is the branch over the `else' part.
532 TEMP to the jump insn preceding "x = a;"
534 TEMP2 to the insn that sets "x = b;"
535 TEMP3 to the insn that sets "x = a;"
536 TEMP4 to the set of "x = b"; */
538 if (this_is_simplejump
539 && (temp3
= prev_active_insn (insn
)) != 0
540 && GET_CODE (temp3
) == INSN
541 && (temp4
= single_set (temp3
)) != 0
542 && GET_CODE (temp1
= SET_DEST (temp4
)) == REG
543 && (! SMALL_REGISTER_CLASSES
544 || REGNO (temp1
) >= FIRST_PSEUDO_REGISTER
)
545 && (temp2
= next_active_insn (insn
)) != 0
546 && GET_CODE (temp2
) == INSN
547 && (temp4
= single_set (temp2
)) != 0
548 && rtx_equal_p (SET_DEST (temp4
), temp1
)
549 && ! side_effects_p (SET_SRC (temp4
))
550 && ! may_trap_p (SET_SRC (temp4
))
551 && (REG_NOTES (temp2
) == 0
552 || ((REG_NOTE_KIND (REG_NOTES (temp2
)) == REG_EQUAL
553 || REG_NOTE_KIND (REG_NOTES (temp2
)) == REG_EQUIV
)
554 && XEXP (REG_NOTES (temp2
), 1) == 0
555 && rtx_equal_p (XEXP (REG_NOTES (temp2
), 0),
557 && (temp
= prev_active_insn (temp3
)) != 0
558 && condjump_p (temp
) && ! simplejump_p (temp
)
559 /* TEMP must skip over the "x = a;" insn */
560 && prev_real_insn (JUMP_LABEL (temp
)) == insn
561 && no_labels_between_p (insn
, JUMP_LABEL (temp
))
562 /* There must be no other entries to the "x = b;" insn. */
563 && no_labels_between_p (JUMP_LABEL (temp
), temp2
)
564 /* INSN must either branch to the insn after TEMP2 or the insn
565 after TEMP2 must branch to the same place as INSN. */
566 && (reallabelprev
== temp2
567 || ((temp5
= next_active_insn (temp2
)) != 0
568 && simplejump_p (temp5
)
569 && JUMP_LABEL (temp5
) == JUMP_LABEL (insn
))))
571 /* The test expression, X, may be a complicated test with
572 multiple branches. See if we can find all the uses of
573 the label that TEMP branches to without hitting a CALL_INSN
574 or a jump to somewhere else. */
575 rtx target
= JUMP_LABEL (temp
);
576 int nuses
= LABEL_NUSES (target
);
582 /* Set P to the first jump insn that goes around "x = a;". */
583 for (p
= temp
; nuses
&& p
; p
= prev_nonnote_insn (p
))
585 if (GET_CODE (p
) == JUMP_INSN
)
587 if (condjump_p (p
) && ! simplejump_p (p
)
588 && JUMP_LABEL (p
) == target
)
597 else if (GET_CODE (p
) == CALL_INSN
)
602 /* We cannot insert anything between a set of cc and its use
603 so if P uses cc0, we must back up to the previous insn. */
604 q
= prev_nonnote_insn (p
);
605 if (q
&& GET_RTX_CLASS (GET_CODE (q
)) == 'i'
606 && sets_cc0_p (PATTERN (q
)))
613 /* If we found all the uses and there was no data conflict, we
614 can move the assignment unless we can branch into the middle
617 && no_labels_between_p (p
, insn
)
618 && ! reg_referenced_between_p (temp1
, p
, NEXT_INSN (temp3
))
619 && ! reg_set_between_p (temp1
, p
, temp3
)
620 && (GET_CODE (SET_SRC (temp4
)) == CONST_INT
621 || ! modified_between_p (SET_SRC (temp4
), p
, temp2
))
622 /* Verify that registers used by the jump are not clobbered
623 by the instruction being moved. */
624 && ! regs_set_between_p (PATTERN (temp
),
628 emit_insn_after_with_line_notes (PATTERN (temp2
), p
, temp2
);
631 /* Set NEXT to an insn that we know won't go away. */
632 next
= next_active_insn (insn
);
634 /* Delete the jump around the set. Note that we must do
635 this before we redirect the test jumps so that it won't
636 delete the code immediately following the assignment
637 we moved (which might be a jump). */
641 /* We either have two consecutive labels or a jump to
642 a jump, so adjust all the JUMP_INSNs to branch to where
644 for (p
= NEXT_INSN (p
); p
!= next
; p
= NEXT_INSN (p
))
645 if (GET_CODE (p
) == JUMP_INSN
)
646 redirect_jump (p
, target
);
649 next
= NEXT_INSN (insn
);
654 /* Simplify if (...) { x = a; goto l; } x = b; by converting it
655 to x = a; if (...) goto l; x = b;
656 if A is sufficiently simple, the test doesn't involve X,
657 and nothing in the test modifies A or X.
659 If we have small register classes, we also can't do this if X
662 If the "x = a;" insn has any REG_NOTES, we don't do this because
663 of the possibility that we are running after CSE and there is a
664 REG_EQUAL note that is only valid if the branch has already been
665 taken. If we move the insn with the REG_EQUAL note, we may
666 fold the comparison to always be false in a later CSE pass.
667 (We could also delete the REG_NOTES when moving the insn, but it
668 seems simpler to not move it.) An exception is that we can move
669 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
670 value is the same as "a".
676 TEMP to the jump insn preceding "x = a;"
678 TEMP2 to the insn that sets "x = b;"
679 TEMP3 to the insn that sets "x = a;"
680 TEMP4 to the set of "x = a"; */
682 if (this_is_simplejump
683 && (temp2
= next_active_insn (insn
)) != 0
684 && GET_CODE (temp2
) == INSN
685 && (temp4
= single_set (temp2
)) != 0
686 && GET_CODE (temp1
= SET_DEST (temp4
)) == REG
687 && (! SMALL_REGISTER_CLASSES
688 || REGNO (temp1
) >= FIRST_PSEUDO_REGISTER
)
689 && (temp3
= prev_active_insn (insn
)) != 0
690 && GET_CODE (temp3
) == INSN
691 && (temp4
= single_set (temp3
)) != 0
692 && rtx_equal_p (SET_DEST (temp4
), temp1
)
693 && ! side_effects_p (SET_SRC (temp4
))
694 && ! may_trap_p (SET_SRC (temp4
))
695 && (REG_NOTES (temp3
) == 0
696 || ((REG_NOTE_KIND (REG_NOTES (temp3
)) == REG_EQUAL
697 || REG_NOTE_KIND (REG_NOTES (temp3
)) == REG_EQUIV
)
698 && XEXP (REG_NOTES (temp3
), 1) == 0
699 && rtx_equal_p (XEXP (REG_NOTES (temp3
), 0),
701 && (temp
= prev_active_insn (temp3
)) != 0
702 && condjump_p (temp
) && ! simplejump_p (temp
)
703 /* TEMP must skip over the "x = a;" insn */
704 && prev_real_insn (JUMP_LABEL (temp
)) == insn
705 && no_labels_between_p (temp
, insn
))
707 rtx prev_label
= JUMP_LABEL (temp
);
708 rtx insert_after
= prev_nonnote_insn (temp
);
711 /* We cannot insert anything between a set of cc and its use. */
712 if (insert_after
&& GET_RTX_CLASS (GET_CODE (insert_after
)) == 'i'
713 && sets_cc0_p (PATTERN (insert_after
)))
714 insert_after
= prev_nonnote_insn (insert_after
);
716 ++LABEL_NUSES (prev_label
);
719 && no_labels_between_p (insert_after
, temp
)
720 && ! reg_referenced_between_p (temp1
, insert_after
, temp3
)
721 && ! reg_referenced_between_p (temp1
, temp3
,
723 && ! reg_set_between_p (temp1
, insert_after
, temp
)
724 && ! modified_between_p (SET_SRC (temp4
), insert_after
, temp
)
725 /* Verify that registers used by the jump are not clobbered
726 by the instruction being moved. */
727 && ! regs_set_between_p (PATTERN (temp
),
730 && invert_jump (temp
, JUMP_LABEL (insn
)))
732 emit_insn_after_with_line_notes (PATTERN (temp3
),
733 insert_after
, temp3
);
736 /* Set NEXT to an insn that we know won't go away. */
740 if (prev_label
&& --LABEL_NUSES (prev_label
) == 0)
741 delete_insn (prev_label
);
746 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
748 /* If we have if (...) x = exp; and branches are expensive,
749 EXP is a single insn, does not have any side effects, cannot
750 trap, and is not too costly, convert this to
751 t = exp; if (...) x = t;
753 Don't do this when we have CC0 because it is unlikely to help
754 and we'd need to worry about where to place the new insn and
755 the potential for conflicts. We also can't do this when we have
756 notes on the insn for the same reason as above.
758 If we have conditional arithmetic, this will make this
759 harder to optimize later and isn't needed, so don't do it
764 TEMP to the "x = exp;" insn.
765 TEMP1 to the single set in the "x = exp;" insn.
768 if (! reload_completed
769 && this_is_condjump
&& ! this_is_simplejump
771 && (temp
= next_nonnote_insn (insn
)) != 0
772 && GET_CODE (temp
) == INSN
773 && REG_NOTES (temp
) == 0
774 && (reallabelprev
== temp
775 || ((temp2
= next_active_insn (temp
)) != 0
776 && simplejump_p (temp2
)
777 && JUMP_LABEL (temp2
) == JUMP_LABEL (insn
)))
778 && (temp1
= single_set (temp
)) != 0
779 && (temp2
= SET_DEST (temp1
), GET_CODE (temp2
) == REG
)
780 && (! SMALL_REGISTER_CLASSES
781 || REGNO (temp2
) >= FIRST_PSEUDO_REGISTER
)
782 && GET_CODE (SET_SRC (temp1
)) != REG
783 && GET_CODE (SET_SRC (temp1
)) != SUBREG
784 && GET_CODE (SET_SRC (temp1
)) != CONST_INT
785 && ! side_effects_p (SET_SRC (temp1
))
786 && ! may_trap_p (SET_SRC (temp1
))
787 && rtx_cost (SET_SRC (temp1
), SET
) < 10)
789 rtx
new = gen_reg_rtx (GET_MODE (temp2
));
791 if ((temp3
= find_insert_position (insn
, temp
))
792 && validate_change (temp
, &SET_DEST (temp1
), new, 0))
794 next
= emit_insn_after (gen_move_insn (temp2
, new), insn
);
795 emit_insn_after_with_line_notes (PATTERN (temp
),
796 PREV_INSN (temp3
), temp
);
798 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
802 reg_scan_update (temp3
, NEXT_INSN (next
), old_max_reg
);
803 old_max_reg
= max_reg_num ();
808 /* Similarly, if it takes two insns to compute EXP but they
809 have the same destination. Here TEMP3 will be the second
810 insn and TEMP4 the SET from that insn. */
812 if (! reload_completed
813 && this_is_condjump
&& ! this_is_simplejump
815 && (temp
= next_nonnote_insn (insn
)) != 0
816 && GET_CODE (temp
) == INSN
817 && REG_NOTES (temp
) == 0
818 && (temp3
= next_nonnote_insn (temp
)) != 0
819 && GET_CODE (temp3
) == INSN
820 && REG_NOTES (temp3
) == 0
821 && (reallabelprev
== temp3
822 || ((temp2
= next_active_insn (temp3
)) != 0
823 && simplejump_p (temp2
)
824 && JUMP_LABEL (temp2
) == JUMP_LABEL (insn
)))
825 && (temp1
= single_set (temp
)) != 0
826 && (temp2
= SET_DEST (temp1
), GET_CODE (temp2
) == REG
)
827 && GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
828 && (! SMALL_REGISTER_CLASSES
829 || REGNO (temp2
) >= FIRST_PSEUDO_REGISTER
)
830 && ! side_effects_p (SET_SRC (temp1
))
831 && ! may_trap_p (SET_SRC (temp1
))
832 && rtx_cost (SET_SRC (temp1
), SET
) < 10
833 && (temp4
= single_set (temp3
)) != 0
834 && rtx_equal_p (SET_DEST (temp4
), temp2
)
835 && ! side_effects_p (SET_SRC (temp4
))
836 && ! may_trap_p (SET_SRC (temp4
))
837 && rtx_cost (SET_SRC (temp4
), SET
) < 10)
839 rtx
new = gen_reg_rtx (GET_MODE (temp2
));
841 if ((temp5
= find_insert_position (insn
, temp
))
842 && (temp6
= find_insert_position (insn
, temp3
))
843 && validate_change (temp
, &SET_DEST (temp1
), new, 0))
845 /* Use the earliest of temp5 and temp6. */
848 next
= emit_insn_after (gen_move_insn (temp2
, new), insn
);
849 emit_insn_after_with_line_notes (PATTERN (temp
),
850 PREV_INSN (temp6
), temp
);
851 emit_insn_after_with_line_notes
852 (replace_rtx (PATTERN (temp3
), temp2
, new),
853 PREV_INSN (temp6
), temp3
);
856 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
860 reg_scan_update (temp6
, NEXT_INSN (next
), old_max_reg
);
861 old_max_reg
= max_reg_num ();
866 /* Finally, handle the case where two insns are used to
867 compute EXP but a temporary register is used. Here we must
868 ensure that the temporary register is not used anywhere else. */
870 if (! reload_completed
872 && this_is_condjump
&& ! this_is_simplejump
874 && (temp
= next_nonnote_insn (insn
)) != 0
875 && GET_CODE (temp
) == INSN
876 && REG_NOTES (temp
) == 0
877 && (temp3
= next_nonnote_insn (temp
)) != 0
878 && GET_CODE (temp3
) == INSN
879 && REG_NOTES (temp3
) == 0
880 && (reallabelprev
== temp3
881 || ((temp2
= next_active_insn (temp3
)) != 0
882 && simplejump_p (temp2
)
883 && JUMP_LABEL (temp2
) == JUMP_LABEL (insn
)))
884 && (temp1
= single_set (temp
)) != 0
885 && (temp5
= SET_DEST (temp1
),
886 (GET_CODE (temp5
) == REG
887 || (GET_CODE (temp5
) == SUBREG
888 && (temp5
= SUBREG_REG (temp5
),
889 GET_CODE (temp5
) == REG
))))
890 && REGNO (temp5
) >= FIRST_PSEUDO_REGISTER
891 && REGNO_FIRST_UID (REGNO (temp5
)) == INSN_UID (temp
)
892 && REGNO_LAST_UID (REGNO (temp5
)) == INSN_UID (temp3
)
893 && ! side_effects_p (SET_SRC (temp1
))
894 && ! may_trap_p (SET_SRC (temp1
))
895 && rtx_cost (SET_SRC (temp1
), SET
) < 10
896 && (temp4
= single_set (temp3
)) != 0
897 && (temp2
= SET_DEST (temp4
), GET_CODE (temp2
) == REG
)
898 && GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
899 && (! SMALL_REGISTER_CLASSES
900 || REGNO (temp2
) >= FIRST_PSEUDO_REGISTER
)
901 && rtx_equal_p (SET_DEST (temp4
), temp2
)
902 && ! side_effects_p (SET_SRC (temp4
))
903 && ! may_trap_p (SET_SRC (temp4
))
904 && rtx_cost (SET_SRC (temp4
), SET
) < 10)
906 rtx
new = gen_reg_rtx (GET_MODE (temp2
));
908 if ((temp5
= find_insert_position (insn
, temp
))
909 && (temp6
= find_insert_position (insn
, temp3
))
910 && validate_change (temp3
, &SET_DEST (temp4
), new, 0))
912 /* Use the earliest of temp5 and temp6. */
915 next
= emit_insn_after (gen_move_insn (temp2
, new), insn
);
916 emit_insn_after_with_line_notes (PATTERN (temp
),
917 PREV_INSN (temp6
), temp
);
918 emit_insn_after_with_line_notes (PATTERN (temp3
),
919 PREV_INSN (temp6
), temp3
);
922 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
926 reg_scan_update (temp6
, NEXT_INSN (next
), old_max_reg
);
927 old_max_reg
= max_reg_num ();
931 #endif /* HAVE_cc0 */
933 #ifdef HAVE_conditional_arithmetic
934 /* ??? This is disabled in genconfig, as this simple-minded
935 transformation can incredibly lengthen register lifetimes.
937 Consider this example from cexp.c's yyparse:
940 (if_then_else (ne (reg:DI 149) (const_int 0 [0x0]))
941 (label_ref 248) (pc)))
942 237 (set (reg/i:DI 0 $0) (const_int 1 [0x1]))
943 239 (set (pc) (label_ref 2382))
944 248 (code_label ("yybackup"))
946 This will be transformed to:
948 237 (set (reg/i:DI 0 $0)
949 (if_then_else:DI (eq (reg:DI 149) (const_int 0 [0x0]))
950 (const_int 1 [0x1]) (reg/i:DI 0 $0)))
952 (if_then_else (eq (reg:DI 149) (const_int 0 [0x0]))
953 (label_ref 2382) (pc)))
955 which, from this narrow viewpoint looks fine. Except that
956 between this and 3 other ocurrences of the same pattern, $0
957 is now live for basically the entire function, and we'll
958 get an abort in caller_save.
960 Any replacement for this code should recall that a set of
961 a register that is not live need not, and indeed should not,
962 be conditionalized. Either that, or delay the transformation
963 until after register allocation. */
965 /* See if this is a conditional jump around a small number of
966 instructions that we can conditionalize. Don't do this before
967 the initial CSE pass or after reload.
969 We reject any insns that have side effects or may trap.
970 Strictly speaking, this is not needed since the machine may
971 support conditionalizing these too, but we won't deal with that
972 now. Specifically, this means that we can't conditionalize a
973 CALL_INSN, which some machines, such as the ARC, can do, but
974 this is a very minor optimization. */
975 if (this_is_condjump
&& ! this_is_simplejump
976 && cse_not_expected
&& ! reload_completed
978 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (insn
)), 0),
981 rtx ourcond
= XEXP (SET_SRC (PATTERN (insn
)), 0);
983 char *storage
= (char *) oballoc (0);
984 int last_insn
= 0, failed
= 0;
985 rtx changed_jump
= 0;
987 ourcond
= gen_rtx (reverse_condition (GET_CODE (ourcond
)),
988 VOIDmode
, XEXP (ourcond
, 0),
991 /* Scan forward BRANCH_COST real insns looking for the JUMP_LABEL
992 of this insn. We see if we think we can conditionalize the
993 insns we pass. For now, we only deal with insns that have
994 one SET. We stop after an insn that modifies anything in
995 OURCOND, if we have too many insns, or if we have an insn
996 with a side effect or that may trip. Note that we will
997 be modifying any unconditional jumps we encounter to be
998 conditional; this will have the effect of also doing this
999 optimization on the "else" the next time around. */
1000 for (temp1
= NEXT_INSN (insn
);
1001 num_insns
<= BRANCH_COST
&& ! failed
&& temp1
!= 0
1002 && GET_CODE (temp1
) != CODE_LABEL
;
1003 temp1
= NEXT_INSN (temp1
))
1005 /* Ignore everything but an active insn. */
1006 if (GET_RTX_CLASS (GET_CODE (temp1
)) != 'i'
1007 || GET_CODE (PATTERN (temp1
)) == USE
1008 || GET_CODE (PATTERN (temp1
)) == CLOBBER
)
1011 /* If this was an unconditional jump, record it since we'll
1012 need to remove the BARRIER if we succeed. We can only
1013 have one such jump since there must be a label after
1014 the BARRIER and it's either ours, in which case it's the
1015 only one or some other, in which case we'd fail.
1016 Likewise if it's a CALL_INSN followed by a BARRIER. */
1018 if (simplejump_p (temp1
)
1019 || (GET_CODE (temp1
) == CALL_INSN
1020 && NEXT_INSN (temp1
) != 0
1021 && GET_CODE (NEXT_INSN (temp1
)) == BARRIER
))
1023 if (changed_jump
== 0)
1024 changed_jump
= temp1
;
1027 = gen_rtx_INSN_LIST (VOIDmode
, temp1
, changed_jump
);
1030 /* See if we are allowed another insn and if this insn
1031 if one we think we may be able to handle. */
1032 if (++num_insns
> BRANCH_COST
1034 || (((temp2
= single_set (temp1
)) == 0
1035 || side_effects_p (SET_SRC (temp2
))
1036 || may_trap_p (SET_SRC (temp2
)))
1037 && GET_CODE (temp1
) != CALL_INSN
))
1039 else if (temp2
!= 0)
1040 validate_change (temp1
, &SET_SRC (temp2
),
1041 gen_rtx_IF_THEN_ELSE
1042 (GET_MODE (SET_DEST (temp2
)),
1044 SET_SRC (temp2
), SET_DEST (temp2
)),
1048 /* This is a CALL_INSN that doesn't have a SET. */
1049 rtx
*call_loc
= &PATTERN (temp1
);
1051 if (GET_CODE (*call_loc
) == PARALLEL
)
1052 call_loc
= &XVECEXP (*call_loc
, 0, 0);
1054 validate_change (temp1
, call_loc
,
1055 gen_rtx_IF_THEN_ELSE
1056 (VOIDmode
, copy_rtx (ourcond
),
1057 *call_loc
, const0_rtx
),
1062 if (modified_in_p (ourcond
, temp1
))
1066 /* If we've reached our jump label, haven't failed, and all
1067 the changes above are valid, we can delete this jump
1068 insn. Also remove a BARRIER after any jump that used
1069 to be unconditional and remove any REG_EQUAL or REG_EQUIV
1070 that might have previously been present on insns we
1071 made conditional. */
1072 if (temp1
== JUMP_LABEL (insn
) && ! failed
1073 && apply_change_group ())
1075 for (temp1
= NEXT_INSN (insn
); temp1
!= JUMP_LABEL (insn
);
1076 temp1
= NEXT_INSN (temp1
))
1077 if (GET_RTX_CLASS (GET_CODE (temp1
)) == 'i')
1078 for (temp2
= REG_NOTES (temp1
); temp2
!= 0;
1079 temp2
= XEXP (temp2
, 1))
1080 if (REG_NOTE_KIND (temp2
) == REG_EQUAL
1081 || REG_NOTE_KIND (temp2
) == REG_EQUIV
)
1082 remove_note (temp1
, temp2
);
1084 if (changed_jump
!= 0)
1086 while (GET_CODE (changed_jump
) == INSN_LIST
)
1088 delete_barrier (NEXT_INSN (XEXP (changed_jump
, 0)));
1089 changed_jump
= XEXP (changed_jump
, 1);
1092 delete_barrier (NEXT_INSN (changed_jump
));
1106 /* If branches are expensive, convert
1107 if (foo) bar++; to bar += (foo != 0);
1108 and similarly for "bar--;"
1110 INSN is the conditional branch around the arithmetic. We set:
1112 TEMP is the arithmetic insn.
1113 TEMP1 is the SET doing the arithmetic.
1114 TEMP2 is the operand being incremented or decremented.
1115 TEMP3 to the condition being tested.
1116 TEMP4 to the earliest insn used to find the condition. */
1118 if ((BRANCH_COST
>= 2
1126 && ! reload_completed
1127 && this_is_condjump
&& ! this_is_simplejump
1128 && (temp
= next_nonnote_insn (insn
)) != 0
1129 && (temp1
= single_set (temp
)) != 0
1130 && (temp2
= SET_DEST (temp1
),
1131 GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
)
1132 && GET_CODE (SET_SRC (temp1
)) == PLUS
1133 && (XEXP (SET_SRC (temp1
), 1) == const1_rtx
1134 || XEXP (SET_SRC (temp1
), 1) == constm1_rtx
)
1135 && rtx_equal_p (temp2
, XEXP (SET_SRC (temp1
), 0))
1136 && ! side_effects_p (temp2
)
1137 && ! may_trap_p (temp2
)
1138 /* INSN must either branch to the insn after TEMP or the insn
1139 after TEMP must branch to the same place as INSN. */
1140 && (reallabelprev
== temp
1141 || ((temp3
= next_active_insn (temp
)) != 0
1142 && simplejump_p (temp3
)
1143 && JUMP_LABEL (temp3
) == JUMP_LABEL (insn
)))
1144 && (temp3
= get_condition (insn
, &temp4
)) != 0
1145 /* We must be comparing objects whose modes imply the size.
1146 We could handle BLKmode if (1) emit_store_flag could
1147 and (2) we could find the size reliably. */
1148 && GET_MODE (XEXP (temp3
, 0)) != BLKmode
1149 && can_reverse_comparison_p (temp3
, insn
))
1151 rtx temp6
, target
= 0, seq
, init_insn
= 0, init
= temp2
;
1152 enum rtx_code code
= reverse_condition (GET_CODE (temp3
));
1156 /* It must be the case that TEMP2 is not modified in the range
1157 [TEMP4, INSN). The one exception we make is if the insn
1158 before INSN sets TEMP2 to something which is also unchanged
1159 in that range. In that case, we can move the initialization
1160 into our sequence. */
1162 if ((temp5
= prev_active_insn (insn
)) != 0
1163 && no_labels_between_p (temp5
, insn
)
1164 && GET_CODE (temp5
) == INSN
1165 && (temp6
= single_set (temp5
)) != 0
1166 && rtx_equal_p (temp2
, SET_DEST (temp6
))
1167 && (CONSTANT_P (SET_SRC (temp6
))
1168 || GET_CODE (SET_SRC (temp6
)) == REG
1169 || GET_CODE (SET_SRC (temp6
)) == SUBREG
))
1171 emit_insn (PATTERN (temp5
));
1173 init
= SET_SRC (temp6
);
1176 if (CONSTANT_P (init
)
1177 || ! reg_set_between_p (init
, PREV_INSN (temp4
), insn
))
1178 target
= emit_store_flag (gen_reg_rtx (GET_MODE (temp2
)), code
,
1179 XEXP (temp3
, 0), XEXP (temp3
, 1),
1181 (code
== LTU
|| code
== LEU
1182 || code
== GTU
|| code
== GEU
), 1);
1184 /* If we can do the store-flag, do the addition or
1188 target
= expand_binop (GET_MODE (temp2
),
1189 (XEXP (SET_SRC (temp1
), 1) == const1_rtx
1190 ? add_optab
: sub_optab
),
1191 temp2
, target
, temp2
, 0, OPTAB_WIDEN
);
1195 /* Put the result back in temp2 in case it isn't already.
1196 Then replace the jump, possible a CC0-setting insn in
1197 front of the jump, and TEMP, with the sequence we have
1200 if (target
!= temp2
)
1201 emit_move_insn (temp2
, target
);
1206 emit_insns_before (seq
, temp4
);
1210 delete_insn (init_insn
);
1212 next
= NEXT_INSN (insn
);
1214 delete_insn (prev_nonnote_insn (insn
));
1220 reg_scan_update (seq
, NEXT_INSN (next
), old_max_reg
);
1221 old_max_reg
= max_reg_num ();
1231 /* Try to use a conditional move (if the target has them), or a
1232 store-flag insn. If the target has conditional arithmetic as
1233 well as conditional move, the above code will have done something.
1234 Note that we prefer the above code since it is more general: the
1235 code below can make changes that require work to undo.
1237 The general case here is:
1239 1) x = a; if (...) x = b; and
1242 If the jump would be faster, the machine should not have defined
1243 the movcc or scc insns!. These cases are often made by the
1244 previous optimization.
1246 The second case is treated as x = x; if (...) x = b;.
1248 INSN here is the jump around the store. We set:
1250 TEMP to the "x op= b;" insn.
1253 TEMP3 to A (X in the second case).
1254 TEMP4 to the condition being tested.
1255 TEMP5 to the earliest insn used to find the condition.
1256 TEMP6 to the SET of TEMP. */
1258 if (/* We can't do this after reload has completed. */
1260 #ifdef HAVE_conditional_arithmetic
1261 /* Defer this until after CSE so the above code gets the
1262 first crack at it. */
1265 && this_is_condjump
&& ! this_is_simplejump
1266 /* Set TEMP to the "x = b;" insn. */
1267 && (temp
= next_nonnote_insn (insn
)) != 0
1268 && GET_CODE (temp
) == INSN
1269 && (temp6
= single_set (temp
)) != NULL_RTX
1270 && GET_CODE (temp1
= SET_DEST (temp6
)) == REG
1271 && (! SMALL_REGISTER_CLASSES
1272 || REGNO (temp1
) >= FIRST_PSEUDO_REGISTER
)
1273 && ! side_effects_p (temp2
= SET_SRC (temp6
))
1274 && ! may_trap_p (temp2
)
1275 /* Allow either form, but prefer the former if both apply.
1276 There is no point in using the old value of TEMP1 if
1277 it is a register, since cse will alias them. It can
1278 lose if the old value were a hard register since CSE
1279 won't replace hard registers. Avoid using TEMP3 if
1280 small register classes and it is a hard register. */
1281 && (((temp3
= reg_set_last (temp1
, insn
)) != 0
1282 && ! (SMALL_REGISTER_CLASSES
&& GET_CODE (temp3
) == REG
1283 && REGNO (temp3
) < FIRST_PSEUDO_REGISTER
))
1284 /* Make the latter case look like x = x; if (...) x = b; */
1285 || (temp3
= temp1
, 1))
1286 /* INSN must either branch to the insn after TEMP or the insn
1287 after TEMP must branch to the same place as INSN. */
1288 && (reallabelprev
== temp
1289 || ((temp4
= next_active_insn (temp
)) != 0
1290 && simplejump_p (temp4
)
1291 && JUMP_LABEL (temp4
) == JUMP_LABEL (insn
)))
1292 && (temp4
= get_condition (insn
, &temp5
)) != 0
1293 /* We must be comparing objects whose modes imply the size.
1294 We could handle BLKmode if (1) emit_store_flag could
1295 and (2) we could find the size reliably. */
1296 && GET_MODE (XEXP (temp4
, 0)) != BLKmode
1297 /* Even if branches are cheap, the store_flag optimization
1298 can win when the operation to be performed can be
1299 expressed directly. */
1301 /* If the previous insn sets CC0 and something else, we can't
1302 do this since we are going to delete that insn. */
1304 && ! ((temp6
= prev_nonnote_insn (insn
)) != 0
1305 && GET_CODE (temp6
) == INSN
1306 && (sets_cc0_p (PATTERN (temp6
)) == -1
1307 || (sets_cc0_p (PATTERN (temp6
)) == 1
1308 && FIND_REG_INC_NOTE (temp6
, NULL_RTX
))))
1312 #ifdef HAVE_conditional_move
1313 /* First try a conditional move. */
1315 enum rtx_code code
= GET_CODE (temp4
);
1317 rtx cond0
, cond1
, aval
, bval
;
1318 rtx target
, new_insn
;
1320 /* Copy the compared variables into cond0 and cond1, so that
1321 any side effects performed in or after the old comparison,
1322 will not affect our compare which will come later. */
1323 /* ??? Is it possible to just use the comparison in the jump
1324 insn? After all, we're going to delete it. We'd have
1325 to modify emit_conditional_move to take a comparison rtx
1326 instead or write a new function. */
1327 cond0
= gen_reg_rtx (GET_MODE (XEXP (temp4
, 0)));
1328 /* We want the target to be able to simplify comparisons with
1329 zero (and maybe other constants as well), so don't create
1330 pseudos for them. There's no need to either. */
1331 if (GET_CODE (XEXP (temp4
, 1)) == CONST_INT
1332 || GET_CODE (XEXP (temp4
, 1)) == CONST_DOUBLE
)
1333 cond1
= XEXP (temp4
, 1);
1335 cond1
= gen_reg_rtx (GET_MODE (XEXP (temp4
, 1)));
1337 /* Careful about copying these values -- an IOR or what may
1338 need to do other things, like clobber flags. */
1339 /* ??? Assume for the moment that AVAL is ok. */
1344 /* We're dealing with a single_set insn with no side effects
1345 on SET_SRC. We do need to be reasonably certain that if
1346 we need to force BVAL into a register that we won't
1347 clobber the flags -- general_operand should suffice. */
1348 if (general_operand (temp2
, GET_MODE (var
)))
1352 bval
= gen_reg_rtx (GET_MODE (var
));
1353 new_insn
= copy_rtx (temp
);
1354 temp6
= single_set (new_insn
);
1355 SET_DEST (temp6
) = bval
;
1356 emit_insn (PATTERN (new_insn
));
1359 target
= emit_conditional_move (var
, code
,
1360 cond0
, cond1
, VOIDmode
,
1361 aval
, bval
, GET_MODE (var
),
1362 (code
== LTU
|| code
== GEU
1363 || code
== LEU
|| code
== GTU
));
1367 rtx seq1
, seq2
, last
;
1370 /* Save the conditional move sequence but don't emit it
1371 yet. On some machines, like the alpha, it is possible
1372 that temp5 == insn, so next generate the sequence that
1373 saves the compared values and then emit both
1374 sequences ensuring seq1 occurs before seq2. */
1375 seq2
= get_insns ();
1378 /* "Now that we can't fail..." Famous last words.
1379 Generate the copy insns that preserve the compared
1382 emit_move_insn (cond0
, XEXP (temp4
, 0));
1383 if (cond1
!= XEXP (temp4
, 1))
1384 emit_move_insn (cond1
, XEXP (temp4
, 1));
1385 seq1
= get_insns ();
1388 /* Validate the sequence -- this may be some weird
1389 bit-extract-and-test instruction for which there
1390 exists no complimentary bit-extract insn. */
1392 for (last
= seq1
; last
; last
= NEXT_INSN (last
))
1393 if (recog_memoized (last
) < 0)
1401 emit_insns_before (seq1
, temp5
);
1403 /* Insert conditional move after insn, to be sure
1404 that the jump and a possible compare won't be
1406 last
= emit_insns_after (seq2
, insn
);
1408 /* ??? We can also delete the insn that sets X to A.
1409 Flow will do it too though. */
1411 next
= NEXT_INSN (insn
);
1416 reg_scan_update (seq1
, NEXT_INSN (last
),
1418 old_max_reg
= max_reg_num ();
1430 /* That didn't work, try a store-flag insn.
1432 We further divide the cases into:
1434 1) x = a; if (...) x = b; and either A or B is zero,
1435 2) if (...) x = 0; and jumps are expensive,
1436 3) x = a; if (...) x = b; and A and B are constants where all
1437 the set bits in A are also set in B and jumps are expensive,
1438 4) x = a; if (...) x = b; and A and B non-zero, and jumps are
1440 5) if (...) x = b; if jumps are even more expensive. */
1442 if (GET_MODE_CLASS (GET_MODE (temp1
)) == MODE_INT
1443 /* We will be passing this as operand into expand_and. No
1444 good if it's not valid as an operand. */
1445 && general_operand (temp2
, GET_MODE (temp2
))
1446 && ((GET_CODE (temp3
) == CONST_INT
)
1447 /* Make the latter case look like
1448 x = x; if (...) x = 0; */
1451 && temp2
== const0_rtx
)
1452 || BRANCH_COST
>= 3)))
1453 /* If B is zero, OK; if A is zero, can only do (1) if we
1454 can reverse the condition. See if (3) applies possibly
1455 by reversing the condition. Prefer reversing to (4) when
1456 branches are very expensive. */
1457 && (((BRANCH_COST
>= 2
1458 || STORE_FLAG_VALUE
== -1
1459 || (STORE_FLAG_VALUE
== 1
1460 /* Check that the mask is a power of two,
1461 so that it can probably be generated
1463 && GET_CODE (temp3
) == CONST_INT
1464 && exact_log2 (INTVAL (temp3
)) >= 0))
1465 && (reversep
= 0, temp2
== const0_rtx
))
1466 || ((BRANCH_COST
>= 2
1467 || STORE_FLAG_VALUE
== -1
1468 || (STORE_FLAG_VALUE
== 1
1469 && GET_CODE (temp2
) == CONST_INT
1470 && exact_log2 (INTVAL (temp2
)) >= 0))
1471 && temp3
== const0_rtx
1472 && (reversep
= can_reverse_comparison_p (temp4
, insn
)))
1473 || (BRANCH_COST
>= 2
1474 && GET_CODE (temp2
) == CONST_INT
1475 && GET_CODE (temp3
) == CONST_INT
1476 && ((INTVAL (temp2
) & INTVAL (temp3
)) == INTVAL (temp2
)
1477 || ((INTVAL (temp2
) & INTVAL (temp3
)) == INTVAL (temp3
)
1478 && (reversep
= can_reverse_comparison_p (temp4
,
1480 || BRANCH_COST
>= 3)
1483 enum rtx_code code
= GET_CODE (temp4
);
1484 rtx uval
, cval
, var
= temp1
;
1488 /* If necessary, reverse the condition. */
1490 code
= reverse_condition (code
), uval
= temp2
, cval
= temp3
;
1492 uval
= temp3
, cval
= temp2
;
1494 /* If CVAL is non-zero, normalize to -1. Otherwise, if UVAL
1495 is the constant 1, it is best to just compute the result
1496 directly. If UVAL is constant and STORE_FLAG_VALUE
1497 includes all of its bits, it is best to compute the flag
1498 value unnormalized and `and' it with UVAL. Otherwise,
1499 normalize to -1 and `and' with UVAL. */
1500 normalizep
= (cval
!= const0_rtx
? -1
1501 : (uval
== const1_rtx
? 1
1502 : (GET_CODE (uval
) == CONST_INT
1503 && (INTVAL (uval
) & ~STORE_FLAG_VALUE
) == 0)
1506 /* We will be putting the store-flag insn immediately in
1507 front of the comparison that was originally being done,
1508 so we know all the variables in TEMP4 will be valid.
1509 However, this might be in front of the assignment of
1510 A to VAR. If it is, it would clobber the store-flag
1511 we will be emitting.
1513 Therefore, emit into a temporary which will be copied to
1514 VAR immediately after TEMP. */
1517 target
= emit_store_flag (gen_reg_rtx (GET_MODE (var
)), code
,
1518 XEXP (temp4
, 0), XEXP (temp4
, 1),
1520 (code
== LTU
|| code
== LEU
1521 || code
== GEU
|| code
== GTU
),
1531 /* Put the store-flag insns in front of the first insn
1532 used to compute the condition to ensure that we
1533 use the same values of them as the current
1534 comparison. However, the remainder of the insns we
1535 generate will be placed directly in front of the
1536 jump insn, in case any of the pseudos we use
1537 are modified earlier. */
1539 emit_insns_before (seq
, temp5
);
1543 /* Both CVAL and UVAL are non-zero. */
1544 if (cval
!= const0_rtx
&& uval
!= const0_rtx
)
1548 tem1
= expand_and (uval
, target
, NULL_RTX
);
1549 if (GET_CODE (cval
) == CONST_INT
1550 && GET_CODE (uval
) == CONST_INT
1551 && (INTVAL (cval
) & INTVAL (uval
)) == INTVAL (cval
))
1555 tem2
= expand_unop (GET_MODE (var
), one_cmpl_optab
,
1556 target
, NULL_RTX
, 0);
1557 tem2
= expand_and (cval
, tem2
,
1558 (GET_CODE (tem2
) == REG
1562 /* If we usually make new pseudos, do so here. This
1563 turns out to help machines that have conditional
1565 /* ??? Conditional moves have already been handled.
1566 This may be obsolete. */
1568 if (flag_expensive_optimizations
)
1571 target
= expand_binop (GET_MODE (var
), ior_optab
,
1575 else if (normalizep
!= 1)
1577 /* We know that either CVAL or UVAL is zero. If
1578 UVAL is zero, negate TARGET and `and' with CVAL.
1579 Otherwise, `and' with UVAL. */
1580 if (uval
== const0_rtx
)
1582 target
= expand_unop (GET_MODE (var
), one_cmpl_optab
,
1583 target
, NULL_RTX
, 0);
1587 target
= expand_and (uval
, target
,
1588 (GET_CODE (target
) == REG
1589 && ! preserve_subexpressions_p ()
1590 ? target
: NULL_RTX
));
1593 emit_move_insn (var
, target
);
1597 /* If INSN uses CC0, we must not separate it from the
1598 insn that sets cc0. */
1599 if (reg_mentioned_p (cc0_rtx
, PATTERN (before
)))
1600 before
= prev_nonnote_insn (before
);
1602 emit_insns_before (seq
, before
);
1605 next
= NEXT_INSN (insn
);
1610 reg_scan_update (seq
, NEXT_INSN (next
), old_max_reg
);
1611 old_max_reg
= max_reg_num ();
1623 /* Simplify if (...) x = 1; else {...} if (x) ...
1624 We recognize this case scanning backwards as well.
1626 TEMP is the assignment to x;
1627 TEMP1 is the label at the head of the second if. */
1628 /* ?? This should call get_condition to find the values being
1629 compared, instead of looking for a COMPARE insn when HAVE_cc0
1630 is not defined. This would allow it to work on the m88k. */
1631 /* ?? This optimization is only safe before cse is run if HAVE_cc0
1632 is not defined and the condition is tested by a separate compare
1633 insn. This is because the code below assumes that the result
1634 of the compare dies in the following branch.
1636 Not only that, but there might be other insns between the
1637 compare and branch whose results are live. Those insns need
1640 A way to fix this is to move the insns at JUMP_LABEL (insn)
1641 to before INSN. If we are running before flow, they will
1642 be deleted if they aren't needed. But this doesn't work
1645 This is really a special-case of jump threading, anyway. The
1646 right thing to do is to replace this and jump threading with
1647 much simpler code in cse.
1649 This code has been turned off in the non-cc0 case in the
1653 else if (this_is_simplejump
1654 /* Safe to skip USE and CLOBBER insns here
1655 since they will not be deleted. */
1656 && (temp
= prev_active_insn (insn
))
1657 && no_labels_between_p (temp
, insn
)
1658 && GET_CODE (temp
) == INSN
1659 && GET_CODE (PATTERN (temp
)) == SET
1660 && GET_CODE (SET_DEST (PATTERN (temp
))) == REG
1661 && CONSTANT_P (SET_SRC (PATTERN (temp
)))
1662 && (temp1
= next_active_insn (JUMP_LABEL (insn
)))
1663 /* If we find that the next value tested is `x'
1664 (TEMP1 is the insn where this happens), win. */
1665 && GET_CODE (temp1
) == INSN
1666 && GET_CODE (PATTERN (temp1
)) == SET
1668 /* Does temp1 `tst' the value of x? */
1669 && SET_SRC (PATTERN (temp1
)) == SET_DEST (PATTERN (temp
))
1670 && SET_DEST (PATTERN (temp1
)) == cc0_rtx
1671 && (temp1
= next_nonnote_insn (temp1
))
1673 /* Does temp1 compare the value of x against zero? */
1674 && GET_CODE (SET_SRC (PATTERN (temp1
))) == COMPARE
1675 && XEXP (SET_SRC (PATTERN (temp1
)), 1) == const0_rtx
1676 && (XEXP (SET_SRC (PATTERN (temp1
)), 0)
1677 == SET_DEST (PATTERN (temp
)))
1678 && GET_CODE (SET_DEST (PATTERN (temp1
))) == REG
1679 && (temp1
= find_next_ref (SET_DEST (PATTERN (temp1
)), temp1
))
1681 && condjump_p (temp1
))
1683 /* Get the if_then_else from the condjump. */
1684 rtx choice
= SET_SRC (PATTERN (temp1
));
1685 if (GET_CODE (choice
) == IF_THEN_ELSE
)
1687 enum rtx_code code
= GET_CODE (XEXP (choice
, 0));
1688 rtx val
= SET_SRC (PATTERN (temp
));
1690 = simplify_relational_operation (code
, GET_MODE (SET_DEST (PATTERN (temp
))),
1694 if (cond
== const_true_rtx
)
1695 ultimate
= XEXP (choice
, 1);
1696 else if (cond
== const0_rtx
)
1697 ultimate
= XEXP (choice
, 2);
1701 if (ultimate
== pc_rtx
)
1702 ultimate
= get_label_after (temp1
);
1703 else if (ultimate
&& GET_CODE (ultimate
) != RETURN
)
1704 ultimate
= XEXP (ultimate
, 0);
1706 if (ultimate
&& JUMP_LABEL(insn
) != ultimate
)
1707 changed
|= redirect_jump (insn
, ultimate
);
1713 /* @@ This needs a bit of work before it will be right.
1715 Any type of comparison can be accepted for the first and
1716 second compare. When rewriting the first jump, we must
1717 compute the what conditions can reach label3, and use the
1718 appropriate code. We can not simply reverse/swap the code
1719 of the first jump. In some cases, the second jump must be
1723 < == converts to > ==
1724 < != converts to == >
1727 If the code is written to only accept an '==' test for the second
1728 compare, then all that needs to be done is to swap the condition
1729 of the first branch.
1731 It is questionable whether we want this optimization anyways,
1732 since if the user wrote code like this because he/she knew that
1733 the jump to label1 is taken most of the time, then rewriting
1734 this gives slower code. */
1735 /* @@ This should call get_condition to find the values being
1736 compared, instead of looking for a COMPARE insn when HAVE_cc0
1737 is not defined. This would allow it to work on the m88k. */
1738 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1739 is not defined and the condition is tested by a separate compare
1740 insn. This is because the code below assumes that the result
1741 of the compare dies in the following branch. */
1743 /* Simplify test a ~= b
1757 where ~= is an inequality, e.g. >, and ~~= is the swapped
1760 We recognize this case scanning backwards.
1762 TEMP is the conditional jump to `label2';
1763 TEMP1 is the test for `a == b';
1764 TEMP2 is the conditional jump to `label1';
1765 TEMP3 is the test for `a ~= b'. */
1766 else if (this_is_simplejump
1767 && (temp
= prev_active_insn (insn
))
1768 && no_labels_between_p (temp
, insn
)
1769 && condjump_p (temp
)
1770 && (temp1
= prev_active_insn (temp
))
1771 && no_labels_between_p (temp1
, temp
)
1772 && GET_CODE (temp1
) == INSN
1773 && GET_CODE (PATTERN (temp1
)) == SET
1775 && sets_cc0_p (PATTERN (temp1
)) == 1
1777 && GET_CODE (SET_SRC (PATTERN (temp1
))) == COMPARE
1778 && GET_CODE (SET_DEST (PATTERN (temp1
))) == REG
1779 && (temp
== find_next_ref (SET_DEST (PATTERN (temp1
)), temp1
))
1781 && (temp2
= prev_active_insn (temp1
))
1782 && no_labels_between_p (temp2
, temp1
)
1783 && condjump_p (temp2
)
1784 && JUMP_LABEL (temp2
) == next_nonnote_insn (NEXT_INSN (insn
))
1785 && (temp3
= prev_active_insn (temp2
))
1786 && no_labels_between_p (temp3
, temp2
)
1787 && GET_CODE (PATTERN (temp3
)) == SET
1788 && rtx_equal_p (SET_DEST (PATTERN (temp3
)),
1789 SET_DEST (PATTERN (temp1
)))
1790 && rtx_equal_p (SET_SRC (PATTERN (temp1
)),
1791 SET_SRC (PATTERN (temp3
)))
1792 && ! inequality_comparisons_p (PATTERN (temp
))
1793 && inequality_comparisons_p (PATTERN (temp2
)))
1795 rtx fallthrough_label
= JUMP_LABEL (temp2
);
1797 ++LABEL_NUSES (fallthrough_label
);
1798 if (swap_jump (temp2
, JUMP_LABEL (insn
)))
1804 if (--LABEL_NUSES (fallthrough_label
) == 0)
1805 delete_insn (fallthrough_label
);
1808 /* Simplify if (...) {... x = 1;} if (x) ...
1810 We recognize this case backwards.
1812 TEMP is the test of `x';
1813 TEMP1 is the assignment to `x' at the end of the
1814 previous statement. */
1815 /* @@ This should call get_condition to find the values being
1816 compared, instead of looking for a COMPARE insn when HAVE_cc0
1817 is not defined. This would allow it to work on the m88k. */
1818 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1819 is not defined and the condition is tested by a separate compare
1820 insn. This is because the code below assumes that the result
1821 of the compare dies in the following branch. */
1823 /* ??? This has to be turned off. The problem is that the
1824 unconditional jump might indirectly end up branching to the
1825 label between TEMP1 and TEMP. We can't detect this, in general,
1826 since it may become a jump to there after further optimizations.
1827 If that jump is done, it will be deleted, so we will retry
1828 this optimization in the next pass, thus an infinite loop.
1830 The present code prevents this by putting the jump after the
1831 label, but this is not logically correct. */
1833 else if (this_is_condjump
1834 /* Safe to skip USE and CLOBBER insns here
1835 since they will not be deleted. */
1836 && (temp
= prev_active_insn (insn
))
1837 && no_labels_between_p (temp
, insn
)
1838 && GET_CODE (temp
) == INSN
1839 && GET_CODE (PATTERN (temp
)) == SET
1841 && sets_cc0_p (PATTERN (temp
)) == 1
1842 && GET_CODE (SET_SRC (PATTERN (temp
))) == REG
1844 /* Temp must be a compare insn, we can not accept a register
1845 to register move here, since it may not be simply a
1847 && GET_CODE (SET_SRC (PATTERN (temp
))) == COMPARE
1848 && XEXP (SET_SRC (PATTERN (temp
)), 1) == const0_rtx
1849 && GET_CODE (XEXP (SET_SRC (PATTERN (temp
)), 0)) == REG
1850 && GET_CODE (SET_DEST (PATTERN (temp
))) == REG
1851 && insn
== find_next_ref (SET_DEST (PATTERN (temp
)), temp
)
1853 /* May skip USE or CLOBBER insns here
1854 for checking for opportunity, since we
1855 take care of them later. */
1856 && (temp1
= prev_active_insn (temp
))
1857 && GET_CODE (temp1
) == INSN
1858 && GET_CODE (PATTERN (temp1
)) == SET
1860 && SET_SRC (PATTERN (temp
)) == SET_DEST (PATTERN (temp1
))
1862 && (XEXP (SET_SRC (PATTERN (temp
)), 0)
1863 == SET_DEST (PATTERN (temp1
)))
1865 && CONSTANT_P (SET_SRC (PATTERN (temp1
)))
1866 /* If this isn't true, cse will do the job. */
1867 && ! no_labels_between_p (temp1
, temp
))
1869 /* Get the if_then_else from the condjump. */
1870 rtx choice
= SET_SRC (PATTERN (insn
));
1871 if (GET_CODE (choice
) == IF_THEN_ELSE
1872 && (GET_CODE (XEXP (choice
, 0)) == EQ
1873 || GET_CODE (XEXP (choice
, 0)) == NE
))
1875 int want_nonzero
= (GET_CODE (XEXP (choice
, 0)) == NE
);
1880 /* Get the place that condjump will jump to
1881 if it is reached from here. */
1882 if ((SET_SRC (PATTERN (temp1
)) != const0_rtx
)
1884 ultimate
= XEXP (choice
, 1);
1886 ultimate
= XEXP (choice
, 2);
1887 /* Get it as a CODE_LABEL. */
1888 if (ultimate
== pc_rtx
)
1889 ultimate
= get_label_after (insn
);
1891 /* Get the label out of the LABEL_REF. */
1892 ultimate
= XEXP (ultimate
, 0);
1894 /* Insert the jump immediately before TEMP, specifically
1895 after the label that is between TEMP1 and TEMP. */
1896 last_insn
= PREV_INSN (temp
);
1898 /* If we would be branching to the next insn, the jump
1899 would immediately be deleted and the re-inserted in
1900 a subsequent pass over the code. So don't do anything
1902 if (next_active_insn (last_insn
)
1903 != next_active_insn (ultimate
))
1905 emit_barrier_after (last_insn
);
1906 p
= emit_jump_insn_after (gen_jump (ultimate
),
1908 JUMP_LABEL (p
) = ultimate
;
1909 ++LABEL_NUSES (ultimate
);
1910 if (INSN_UID (ultimate
) < max_jump_chain
1911 && INSN_CODE (p
) < max_jump_chain
)
1913 jump_chain
[INSN_UID (p
)]
1914 = jump_chain
[INSN_UID (ultimate
)];
1915 jump_chain
[INSN_UID (ultimate
)] = p
;
1924 /* Detect a conditional jump jumping over an unconditional trap. */
1926 && this_is_condjump
&& ! this_is_simplejump
1927 && reallabelprev
!= 0
1928 && GET_CODE (reallabelprev
) == INSN
1929 && GET_CODE (PATTERN (reallabelprev
)) == TRAP_IF
1930 && TRAP_CONDITION (PATTERN (reallabelprev
)) == const_true_rtx
1931 && prev_active_insn (reallabelprev
) == insn
1932 && no_labels_between_p (insn
, reallabelprev
)
1933 && (temp2
= get_condition (insn
, &temp4
))
1934 && can_reverse_comparison_p (temp2
, insn
))
1936 rtx
new = gen_cond_trap (reverse_condition (GET_CODE (temp2
)),
1937 XEXP (temp2
, 0), XEXP (temp2
, 1),
1938 TRAP_CODE (PATTERN (reallabelprev
)));
1942 emit_insn_before (new, temp4
);
1943 delete_insn (reallabelprev
);
1949 /* Detect a jump jumping to an unconditional trap. */
1950 else if (HAVE_trap
&& this_is_condjump
1951 && (temp
= next_active_insn (JUMP_LABEL (insn
)))
1952 && GET_CODE (temp
) == INSN
1953 && GET_CODE (PATTERN (temp
)) == TRAP_IF
1954 && (this_is_simplejump
1955 || (temp2
= get_condition (insn
, &temp4
))))
1957 rtx tc
= TRAP_CONDITION (PATTERN (temp
));
1959 if (tc
== const_true_rtx
1960 || (! this_is_simplejump
&& rtx_equal_p (temp2
, tc
)))
1963 /* Replace an unconditional jump to a trap with a trap. */
1964 if (this_is_simplejump
)
1966 emit_barrier_after (emit_insn_before (gen_trap (), insn
));
1971 new = gen_cond_trap (GET_CODE (temp2
), XEXP (temp2
, 0),
1973 TRAP_CODE (PATTERN (temp
)));
1976 emit_insn_before (new, temp4
);
1982 /* If the trap condition and jump condition are mutually
1983 exclusive, redirect the jump to the following insn. */
1984 else if (GET_RTX_CLASS (GET_CODE (tc
)) == '<'
1985 && ! this_is_simplejump
1986 && swap_condition (GET_CODE (temp2
)) == GET_CODE (tc
)
1987 && rtx_equal_p (XEXP (tc
, 0), XEXP (temp2
, 0))
1988 && rtx_equal_p (XEXP (tc
, 1), XEXP (temp2
, 1))
1989 && redirect_jump (insn
, get_label_after (temp
)))
1998 /* Now that the jump has been tensioned,
1999 try cross jumping: check for identical code
2000 before the jump and before its target label. */
2002 /* First, cross jumping of conditional jumps: */
2004 if (cross_jump
&& condjump_p (insn
))
2006 rtx newjpos
, newlpos
;
2007 rtx x
= prev_real_insn (JUMP_LABEL (insn
));
2009 /* A conditional jump may be crossjumped
2010 only if the place it jumps to follows
2011 an opposing jump that comes back here. */
2013 if (x
!= 0 && ! jump_back_p (x
, insn
))
2014 /* We have no opposing jump;
2015 cannot cross jump this insn. */
2019 /* TARGET is nonzero if it is ok to cross jump
2020 to code before TARGET. If so, see if matches. */
2022 find_cross_jump (insn
, x
, 2,
2023 &newjpos
, &newlpos
);
2027 do_cross_jump (insn
, newjpos
, newlpos
);
2028 /* Make the old conditional jump
2029 into an unconditional one. */
2030 SET_SRC (PATTERN (insn
))
2031 = gen_rtx_LABEL_REF (VOIDmode
, JUMP_LABEL (insn
));
2032 INSN_CODE (insn
) = -1;
2033 emit_barrier_after (insn
);
2034 /* Add to jump_chain unless this is a new label
2035 whose UID is too large. */
2036 if (INSN_UID (JUMP_LABEL (insn
)) < max_jump_chain
)
2038 jump_chain
[INSN_UID (insn
)]
2039 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
2040 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
2047 /* Cross jumping of unconditional jumps:
2048 a few differences. */
2050 if (cross_jump
&& simplejump_p (insn
))
2052 rtx newjpos
, newlpos
;
2057 /* TARGET is nonzero if it is ok to cross jump
2058 to code before TARGET. If so, see if matches. */
2059 find_cross_jump (insn
, JUMP_LABEL (insn
), 1,
2060 &newjpos
, &newlpos
);
2062 /* If cannot cross jump to code before the label,
2063 see if we can cross jump to another jump to
2065 /* Try each other jump to this label. */
2066 if (INSN_UID (JUMP_LABEL (insn
)) < max_uid
)
2067 for (target
= jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
2068 target
!= 0 && newjpos
== 0;
2069 target
= jump_chain
[INSN_UID (target
)])
2071 && JUMP_LABEL (target
) == JUMP_LABEL (insn
)
2072 /* Ignore TARGET if it's deleted. */
2073 && ! INSN_DELETED_P (target
))
2074 find_cross_jump (insn
, target
, 2,
2075 &newjpos
, &newlpos
);
2079 do_cross_jump (insn
, newjpos
, newlpos
);
2085 /* This code was dead in the previous jump.c! */
2086 if (cross_jump
&& GET_CODE (PATTERN (insn
)) == RETURN
)
2088 /* Return insns all "jump to the same place"
2089 so we can cross-jump between any two of them. */
2091 rtx newjpos
, newlpos
, target
;
2095 /* If cannot cross jump to code before the label,
2096 see if we can cross jump to another jump to
2098 /* Try each other jump to this label. */
2099 for (target
= jump_chain
[0];
2100 target
!= 0 && newjpos
== 0;
2101 target
= jump_chain
[INSN_UID (target
)])
2103 && ! INSN_DELETED_P (target
)
2104 && GET_CODE (PATTERN (target
)) == RETURN
)
2105 find_cross_jump (insn
, target
, 2,
2106 &newjpos
, &newlpos
);
2110 do_cross_jump (insn
, newjpos
, newlpos
);
2121 /* Delete extraneous line number notes.
2122 Note that two consecutive notes for different lines are not really
2123 extraneous. There should be some indication where that line belonged,
2124 even if it became empty. */
2129 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
2130 if (GET_CODE (insn
) == NOTE
&& NOTE_LINE_NUMBER (insn
) >= 0)
2132 /* Delete this note if it is identical to previous note. */
2134 && NOTE_SOURCE_FILE (insn
) == NOTE_SOURCE_FILE (last_note
)
2135 && NOTE_LINE_NUMBER (insn
) == NOTE_LINE_NUMBER (last_note
))
2148 /* If we fall through to the epilogue, see if we can insert a RETURN insn
2149 in front of it. If the machine allows it at this point (we might be
2150 after reload for a leaf routine), it will improve optimization for it
2151 to be there. We do this both here and at the start of this pass since
2152 the RETURN might have been deleted by some of our optimizations. */
2153 insn
= get_last_insn ();
2154 while (insn
&& GET_CODE (insn
) == NOTE
)
2155 insn
= PREV_INSN (insn
);
2157 if (insn
&& GET_CODE (insn
) != BARRIER
)
2159 emit_jump_insn (gen_return ());
2165 /* CAN_REACH_END is persistent for each function. Once set it should
2166 not be cleared. This is especially true for the case where we
2167 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
2168 the front-end before compiling each function. */
2169 if (calculate_can_reach_end (last_insn
, optimize
!= 0))
2178 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
2179 notes whose labels don't occur in the insn any more. Returns the
2180 largest INSN_UID found. */
2185 int largest_uid
= 0;
2188 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
2190 if (GET_CODE (insn
) == CODE_LABEL
)
2191 LABEL_NUSES (insn
) = (LABEL_PRESERVE_P (insn
) != 0);
2192 else if (GET_CODE (insn
) == JUMP_INSN
)
2193 JUMP_LABEL (insn
) = 0;
2194 else if (GET_CODE (insn
) == INSN
|| GET_CODE (insn
) == CALL_INSN
)
2198 for (note
= REG_NOTES (insn
); note
; note
= next
)
2200 next
= XEXP (note
, 1);
2201 if (REG_NOTE_KIND (note
) == REG_LABEL
2202 && ! reg_mentioned_p (XEXP (note
, 0), PATTERN (insn
)))
2203 remove_note (insn
, note
);
2206 if (INSN_UID (insn
) > largest_uid
)
2207 largest_uid
= INSN_UID (insn
);
2213 /* Delete insns following barriers, up to next label.
2215 Also delete no-op jumps created by gcse. */
2217 delete_barrier_successors (f
)
2222 for (insn
= f
; insn
;)
2224 if (GET_CODE (insn
) == BARRIER
)
2226 insn
= NEXT_INSN (insn
);
2228 never_reached_warning (insn
);
2230 while (insn
!= 0 && GET_CODE (insn
) != CODE_LABEL
)
2232 if (GET_CODE (insn
) == NOTE
2233 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)
2234 insn
= NEXT_INSN (insn
);
2236 insn
= delete_insn (insn
);
2238 /* INSN is now the code_label. */
2240 /* Also remove (set (pc) (pc)) insns which can be created by
2241 gcse. We eliminate such insns now to avoid having them
2242 cause problems later. */
2243 else if (GET_CODE (insn
) == JUMP_INSN
2244 && GET_CODE (PATTERN (insn
)) == SET
2245 && SET_SRC (PATTERN (insn
)) == pc_rtx
2246 && SET_DEST (PATTERN (insn
)) == pc_rtx
)
2247 insn
= delete_insn (insn
);
2250 insn
= NEXT_INSN (insn
);
2254 /* Mark the label each jump jumps to.
2255 Combine consecutive labels, and count uses of labels.
2257 For each label, make a chain (using `jump_chain')
2258 of all the *unconditional* jumps that jump to it;
2259 also make a chain of all returns.
2261 CROSS_JUMP indicates whether we are doing cross jumping
2262 and if we are whether we will be paying attention to
2263 death notes or not. */
2266 mark_all_labels (f
, cross_jump
)
2272 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
2273 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
2275 mark_jump_label (PATTERN (insn
), insn
, cross_jump
);
2276 if (! INSN_DELETED_P (insn
) && GET_CODE (insn
) == JUMP_INSN
)
2278 if (JUMP_LABEL (insn
) != 0 && simplejump_p (insn
))
2280 jump_chain
[INSN_UID (insn
)]
2281 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
2282 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
2284 if (GET_CODE (PATTERN (insn
)) == RETURN
)
2286 jump_chain
[INSN_UID (insn
)] = jump_chain
[0];
2287 jump_chain
[0] = insn
;
2293 /* Delete all labels already not referenced.
2294 Also find and return the last insn. */
2297 delete_unreferenced_labels (f
)
2300 rtx final
= NULL_RTX
;
2303 for (insn
= f
; insn
; )
2305 if (GET_CODE (insn
) == CODE_LABEL
2306 && LABEL_NUSES (insn
) == 0
2307 && LABEL_ALTERNATE_NAME (insn
) == NULL
)
2308 insn
= delete_insn (insn
);
2312 insn
= NEXT_INSN (insn
);
2319 /* Delete various simple forms of moves which have no necessary
2323 delete_noop_moves (f
)
2328 for (insn
= f
; insn
; )
2330 next
= NEXT_INSN (insn
);
2332 if (GET_CODE (insn
) == INSN
)
2334 register rtx body
= PATTERN (insn
);
2336 /* Combine stack_adjusts with following push_insns. */
2337 #ifdef PUSH_ROUNDING
2338 if (GET_CODE (body
) == SET
2339 && SET_DEST (body
) == stack_pointer_rtx
2340 && GET_CODE (SET_SRC (body
)) == PLUS
2341 && XEXP (SET_SRC (body
), 0) == stack_pointer_rtx
2342 && GET_CODE (XEXP (SET_SRC (body
), 1)) == CONST_INT
2343 && INTVAL (XEXP (SET_SRC (body
), 1)) > 0)
2346 rtx stack_adjust_insn
= insn
;
2347 int stack_adjust_amount
= INTVAL (XEXP (SET_SRC (body
), 1));
2348 int total_pushed
= 0;
2351 /* Find all successive push insns. */
2353 /* Don't convert more than three pushes;
2354 that starts adding too many displaced addresses
2355 and the whole thing starts becoming a losing
2360 p
= next_nonnote_insn (p
);
2361 if (p
== 0 || GET_CODE (p
) != INSN
)
2363 pbody
= PATTERN (p
);
2364 if (GET_CODE (pbody
) != SET
)
2366 dest
= SET_DEST (pbody
);
2367 /* Allow a no-op move between the adjust and the push. */
2368 if (GET_CODE (dest
) == REG
2369 && GET_CODE (SET_SRC (pbody
)) == REG
2370 && REGNO (dest
) == REGNO (SET_SRC (pbody
)))
2372 if (! (GET_CODE (dest
) == MEM
2373 && GET_CODE (XEXP (dest
, 0)) == POST_INC
2374 && XEXP (XEXP (dest
, 0), 0) == stack_pointer_rtx
))
2377 if (total_pushed
+ GET_MODE_SIZE (GET_MODE (SET_DEST (pbody
)))
2378 > stack_adjust_amount
)
2380 total_pushed
+= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody
)));
2383 /* Discard the amount pushed from the stack adjust;
2384 maybe eliminate it entirely. */
2385 if (total_pushed
>= stack_adjust_amount
)
2387 delete_computation (stack_adjust_insn
);
2388 total_pushed
= stack_adjust_amount
;
2391 XEXP (SET_SRC (PATTERN (stack_adjust_insn
)), 1)
2392 = GEN_INT (stack_adjust_amount
- total_pushed
);
2394 /* Change the appropriate push insns to ordinary stores. */
2396 while (total_pushed
> 0)
2399 p
= next_nonnote_insn (p
);
2400 if (GET_CODE (p
) != INSN
)
2402 pbody
= PATTERN (p
);
2403 if (GET_CODE (pbody
) != SET
)
2405 dest
= SET_DEST (pbody
);
2406 /* Allow a no-op move between the adjust and the push. */
2407 if (GET_CODE (dest
) == REG
2408 && GET_CODE (SET_SRC (pbody
)) == REG
2409 && REGNO (dest
) == REGNO (SET_SRC (pbody
)))
2411 if (! (GET_CODE (dest
) == MEM
2412 && GET_CODE (XEXP (dest
, 0)) == POST_INC
2413 && XEXP (XEXP (dest
, 0), 0) == stack_pointer_rtx
))
2415 total_pushed
-= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody
)));
2416 /* If this push doesn't fully fit in the space
2417 of the stack adjust that we deleted,
2418 make another stack adjust here for what we
2419 didn't use up. There should be peepholes
2420 to recognize the resulting sequence of insns. */
2421 if (total_pushed
< 0)
2423 emit_insn_before (gen_add2_insn (stack_pointer_rtx
,
2424 GEN_INT (- total_pushed
)),
2429 = plus_constant (stack_pointer_rtx
, total_pushed
);
2434 /* Detect and delete no-op move instructions
2435 resulting from not allocating a parameter in a register. */
2437 if (GET_CODE (body
) == SET
2438 && (SET_DEST (body
) == SET_SRC (body
)
2439 || (GET_CODE (SET_DEST (body
)) == MEM
2440 && GET_CODE (SET_SRC (body
)) == MEM
2441 && rtx_equal_p (SET_SRC (body
), SET_DEST (body
))))
2442 && ! (GET_CODE (SET_DEST (body
)) == MEM
2443 && MEM_VOLATILE_P (SET_DEST (body
)))
2444 && ! (GET_CODE (SET_SRC (body
)) == MEM
2445 && MEM_VOLATILE_P (SET_SRC (body
))))
2446 delete_computation (insn
);
2448 /* Detect and ignore no-op move instructions
2449 resulting from smart or fortuitous register allocation. */
2451 else if (GET_CODE (body
) == SET
)
2453 int sreg
= true_regnum (SET_SRC (body
));
2454 int dreg
= true_regnum (SET_DEST (body
));
2456 if (sreg
== dreg
&& sreg
>= 0)
2458 else if (sreg
>= 0 && dreg
>= 0)
2461 rtx tem
= find_equiv_reg (NULL_RTX
, insn
, 0,
2462 sreg
, NULL_PTR
, dreg
,
2463 GET_MODE (SET_SRC (body
)));
2466 && GET_MODE (tem
) == GET_MODE (SET_DEST (body
)))
2468 /* DREG may have been the target of a REG_DEAD note in
2469 the insn which makes INSN redundant. If so, reorg
2470 would still think it is dead. So search for such a
2471 note and delete it if we find it. */
2472 if (! find_regno_note (insn
, REG_UNUSED
, dreg
))
2473 for (trial
= prev_nonnote_insn (insn
);
2474 trial
&& GET_CODE (trial
) != CODE_LABEL
;
2475 trial
= prev_nonnote_insn (trial
))
2476 if (find_regno_note (trial
, REG_DEAD
, dreg
))
2478 remove_death (dreg
, trial
);
2482 /* Deleting insn could lose a death-note for SREG. */
2483 if ((trial
= find_regno_note (insn
, REG_DEAD
, sreg
)))
2485 /* Change this into a USE so that we won't emit
2486 code for it, but still can keep the note. */
2488 = gen_rtx_USE (VOIDmode
, XEXP (trial
, 0));
2489 INSN_CODE (insn
) = -1;
2490 /* Remove all reg notes but the REG_DEAD one. */
2491 REG_NOTES (insn
) = trial
;
2492 XEXP (trial
, 1) = NULL_RTX
;
2498 else if (dreg
>= 0 && CONSTANT_P (SET_SRC (body
))
2499 && find_equiv_reg (SET_SRC (body
), insn
, 0, dreg
,
2501 GET_MODE (SET_DEST (body
))))
2503 /* This handles the case where we have two consecutive
2504 assignments of the same constant to pseudos that didn't
2505 get a hard reg. Each SET from the constant will be
2506 converted into a SET of the spill register and an
2507 output reload will be made following it. This produces
2508 two loads of the same constant into the same spill
2513 /* Look back for a death note for the first reg.
2514 If there is one, it is no longer accurate. */
2515 while (in_insn
&& GET_CODE (in_insn
) != CODE_LABEL
)
2517 if ((GET_CODE (in_insn
) == INSN
2518 || GET_CODE (in_insn
) == JUMP_INSN
)
2519 && find_regno_note (in_insn
, REG_DEAD
, dreg
))
2521 remove_death (dreg
, in_insn
);
2524 in_insn
= PREV_INSN (in_insn
);
2527 /* Delete the second load of the value. */
2531 else if (GET_CODE (body
) == PARALLEL
)
2533 /* If each part is a set between two identical registers or
2534 a USE or CLOBBER, delete the insn. */
2538 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; i
--)
2540 tem
= XVECEXP (body
, 0, i
);
2541 if (GET_CODE (tem
) == USE
|| GET_CODE (tem
) == CLOBBER
)
2544 if (GET_CODE (tem
) != SET
2545 || (sreg
= true_regnum (SET_SRC (tem
))) < 0
2546 || (dreg
= true_regnum (SET_DEST (tem
))) < 0
2554 /* Also delete insns to store bit fields if they are no-ops. */
2555 /* Not worth the hair to detect this in the big-endian case. */
2556 else if (! BYTES_BIG_ENDIAN
2557 && GET_CODE (body
) == SET
2558 && GET_CODE (SET_DEST (body
)) == ZERO_EXTRACT
2559 && XEXP (SET_DEST (body
), 2) == const0_rtx
2560 && XEXP (SET_DEST (body
), 0) == SET_SRC (body
)
2561 && ! (GET_CODE (SET_SRC (body
)) == MEM
2562 && MEM_VOLATILE_P (SET_SRC (body
))))
2569 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
2570 If so indicate that this function can drop off the end by returning
2573 CHECK_DELETED indicates whether we must check if the note being
2574 searched for has the deleted flag set.
2576 DELETE_FINAL_NOTE indicates whether we should delete the note
2580 calculate_can_reach_end (last
, delete_final_note
)
2582 int delete_final_note
;
2587 while (insn
!= NULL_RTX
)
2591 /* One label can follow the end-note: the return label. */
2592 if (GET_CODE (insn
) == CODE_LABEL
&& n_labels
-- > 0)
2594 /* Ordinary insns can follow it if returning a structure. */
2595 else if (GET_CODE (insn
) == INSN
)
2597 /* If machine uses explicit RETURN insns, no epilogue,
2598 then one of them follows the note. */
2599 else if (GET_CODE (insn
) == JUMP_INSN
2600 && GET_CODE (PATTERN (insn
)) == RETURN
)
2602 /* A barrier can follow the return insn. */
2603 else if (GET_CODE (insn
) == BARRIER
)
2605 /* Other kinds of notes can follow also. */
2606 else if (GET_CODE (insn
) == NOTE
2607 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)
2613 insn
= PREV_INSN (insn
);
2616 /* See if we backed up to the appropriate type of note. */
2617 if (insn
!= NULL_RTX
2618 && GET_CODE (insn
) == NOTE
2619 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_FUNCTION_END
)
2621 if (delete_final_note
)
2629 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
2630 jump. Assume that this unconditional jump is to the exit test code. If
2631 the code is sufficiently simple, make a copy of it before INSN,
2632 followed by a jump to the exit of the loop. Then delete the unconditional
2635 Return 1 if we made the change, else 0.
2637 This is only safe immediately after a regscan pass because it uses the
2638 values of regno_first_uid and regno_last_uid. */
2641 duplicate_loop_exit_test (loop_start
)
2644 rtx insn
, set
, reg
, p
, link
;
2645 rtx copy
= 0, first_copy
= 0;
2647 rtx exitcode
= NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start
)));
2649 int max_reg
= max_reg_num ();
2652 /* Scan the exit code. We do not perform this optimization if any insn:
2656 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
2657 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
2658 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
2661 We also do not do this if we find an insn with ASM_OPERANDS. While
2662 this restriction should not be necessary, copying an insn with
2663 ASM_OPERANDS can confuse asm_noperands in some cases.
2665 Also, don't do this if the exit code is more than 20 insns. */
2667 for (insn
= exitcode
;
2669 && ! (GET_CODE (insn
) == NOTE
2670 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
);
2671 insn
= NEXT_INSN (insn
))
2673 switch (GET_CODE (insn
))
2679 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
2680 a jump immediately after the loop start that branches outside
2681 the loop but within an outer loop, near the exit test.
2682 If we copied this exit test and created a phony
2683 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
2684 before the exit test look like these could be safely moved
2685 out of the loop even if they actually may be never executed.
2686 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
2688 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
2689 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
)
2693 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
2694 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
))
2695 /* If we were to duplicate this code, we would not move
2696 the BLOCK notes, and so debugging the moved code would
2697 be difficult. Thus, we only move the code with -O2 or
2704 /* The code below would grossly mishandle REG_WAS_0 notes,
2705 so get rid of them here. */
2706 while ((p
= find_reg_note (insn
, REG_WAS_0
, NULL_RTX
)) != 0)
2707 remove_note (insn
, p
);
2708 if (++num_insns
> 20
2709 || find_reg_note (insn
, REG_RETVAL
, NULL_RTX
)
2710 || find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
2718 /* Unless INSN is zero, we can do the optimization. */
2724 /* See if any insn sets a register only used in the loop exit code and
2725 not a user variable. If so, replace it with a new register. */
2726 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
2727 if (GET_CODE (insn
) == INSN
2728 && (set
= single_set (insn
)) != 0
2729 && ((reg
= SET_DEST (set
), GET_CODE (reg
) == REG
)
2730 || (GET_CODE (reg
) == SUBREG
2731 && (reg
= SUBREG_REG (reg
), GET_CODE (reg
) == REG
)))
2732 && REGNO (reg
) >= FIRST_PSEUDO_REGISTER
2733 && REGNO_FIRST_UID (REGNO (reg
)) == INSN_UID (insn
))
2735 for (p
= NEXT_INSN (insn
); p
!= lastexit
; p
= NEXT_INSN (p
))
2736 if (REGNO_LAST_UID (REGNO (reg
)) == INSN_UID (p
))
2741 /* We can do the replacement. Allocate reg_map if this is the
2742 first replacement we found. */
2744 reg_map
= (rtx
*) xcalloc (max_reg
, sizeof (rtx
));
2746 REG_LOOP_TEST_P (reg
) = 1;
2748 reg_map
[REGNO (reg
)] = gen_reg_rtx (GET_MODE (reg
));
2752 /* Now copy each insn. */
2753 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
2755 switch (GET_CODE (insn
))
2758 copy
= emit_barrier_before (loop_start
);
2761 /* Only copy line-number notes. */
2762 if (NOTE_LINE_NUMBER (insn
) >= 0)
2764 copy
= emit_note_before (NOTE_LINE_NUMBER (insn
), loop_start
);
2765 NOTE_SOURCE_FILE (copy
) = NOTE_SOURCE_FILE (insn
);
2770 copy
= emit_insn_before (copy_insn (PATTERN (insn
)), loop_start
);
2772 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
2774 mark_jump_label (PATTERN (copy
), copy
, 0);
2776 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
2778 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2779 if (REG_NOTE_KIND (link
) != REG_LABEL
)
2781 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link
),
2784 if (reg_map
&& REG_NOTES (copy
))
2785 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
2789 copy
= emit_jump_insn_before (copy_insn (PATTERN (insn
)), loop_start
);
2791 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
2792 mark_jump_label (PATTERN (copy
), copy
, 0);
2793 if (REG_NOTES (insn
))
2795 REG_NOTES (copy
) = copy_insn_1 (REG_NOTES (insn
));
2797 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
2800 /* If this is a simple jump, add it to the jump chain. */
2802 if (INSN_UID (copy
) < max_jump_chain
&& JUMP_LABEL (copy
)
2803 && simplejump_p (copy
))
2805 jump_chain
[INSN_UID (copy
)]
2806 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
2807 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
2815 /* Record the first insn we copied. We need it so that we can
2816 scan the copied insns for new pseudo registers. */
2821 /* Now clean up by emitting a jump to the end label and deleting the jump
2822 at the start of the loop. */
2823 if (! copy
|| GET_CODE (copy
) != BARRIER
)
2825 copy
= emit_jump_insn_before (gen_jump (get_label_after (insn
)),
2828 /* Record the first insn we copied. We need it so that we can
2829 scan the copied insns for new pseudo registers. This may not
2830 be strictly necessary since we should have copied at least one
2831 insn above. But I am going to be safe. */
2835 mark_jump_label (PATTERN (copy
), copy
, 0);
2836 if (INSN_UID (copy
) < max_jump_chain
2837 && INSN_UID (JUMP_LABEL (copy
)) < max_jump_chain
)
2839 jump_chain
[INSN_UID (copy
)]
2840 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
2841 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
2843 emit_barrier_before (loop_start
);
2846 /* Now scan from the first insn we copied to the last insn we copied
2847 (copy) for new pseudo registers. Do this after the code to jump to
2848 the end label since that might create a new pseudo too. */
2849 reg_scan_update (first_copy
, copy
, max_reg
);
2851 /* Mark the exit code as the virtual top of the converted loop. */
2852 emit_note_before (NOTE_INSN_LOOP_VTOP
, exitcode
);
2854 delete_insn (next_nonnote_insn (loop_start
));
2863 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
2864 loop-end notes between START and END out before START. Assume that
2865 END is not such a note. START may be such a note. Returns the value
2866 of the new starting insn, which may be different if the original start
2870 squeeze_notes (start
, end
)
2876 for (insn
= start
; insn
!= end
; insn
= next
)
2878 next
= NEXT_INSN (insn
);
2879 if (GET_CODE (insn
) == NOTE
2880 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
2881 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
2882 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
2883 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
2884 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
2885 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_VTOP
))
2891 rtx prev
= PREV_INSN (insn
);
2892 PREV_INSN (insn
) = PREV_INSN (start
);
2893 NEXT_INSN (insn
) = start
;
2894 NEXT_INSN (PREV_INSN (insn
)) = insn
;
2895 PREV_INSN (NEXT_INSN (insn
)) = insn
;
2896 NEXT_INSN (prev
) = next
;
2897 PREV_INSN (next
) = prev
;
2905 /* Compare the instructions before insn E1 with those before E2
2906 to find an opportunity for cross jumping.
2907 (This means detecting identical sequences of insns followed by
2908 jumps to the same place, or followed by a label and a jump
2909 to that label, and replacing one with a jump to the other.)
2911 Assume E1 is a jump that jumps to label E2
2912 (that is not always true but it might as well be).
2913 Find the longest possible equivalent sequences
2914 and store the first insns of those sequences into *F1 and *F2.
2915 Store zero there if no equivalent preceding instructions are found.
2917 We give up if we find a label in stream 1.
2918 Actually we could transfer that label into stream 2. */
2921 find_cross_jump (e1
, e2
, minimum
, f1
, f2
)
2926 register rtx i1
= e1
, i2
= e2
;
2927 register rtx p1
, p2
;
2930 rtx last1
= 0, last2
= 0;
2931 rtx afterlast1
= 0, afterlast2
= 0;
2938 i1
= prev_nonnote_insn (i1
);
2940 i2
= PREV_INSN (i2
);
2941 while (i2
&& (GET_CODE (i2
) == NOTE
|| GET_CODE (i2
) == CODE_LABEL
))
2942 i2
= PREV_INSN (i2
);
2947 /* Don't allow the range of insns preceding E1 or E2
2948 to include the other (E2 or E1). */
2949 if (i2
== e1
|| i1
== e2
)
2952 /* If we will get to this code by jumping, those jumps will be
2953 tensioned to go directly to the new label (before I2),
2954 so this cross-jumping won't cost extra. So reduce the minimum. */
2955 if (GET_CODE (i1
) == CODE_LABEL
)
2961 if (i2
== 0 || GET_CODE (i1
) != GET_CODE (i2
))
2964 /* Avoid moving insns across EH regions if either of the insns
2967 && (asynchronous_exceptions
|| GET_CODE (i1
) == CALL_INSN
)
2968 && !in_same_eh_region (i1
, i2
))
2974 /* If this is a CALL_INSN, compare register usage information.
2975 If we don't check this on stack register machines, the two
2976 CALL_INSNs might be merged leaving reg-stack.c with mismatching
2977 numbers of stack registers in the same basic block.
2978 If we don't check this on machines with delay slots, a delay slot may
2979 be filled that clobbers a parameter expected by the subroutine.
2981 ??? We take the simple route for now and assume that if they're
2982 equal, they were constructed identically. */
2984 if (GET_CODE (i1
) == CALL_INSN
2985 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1
),
2986 CALL_INSN_FUNCTION_USAGE (i2
)))
2990 /* If cross_jump_death_matters is not 0, the insn's mode
2991 indicates whether or not the insn contains any stack-like
2994 if (!lose
&& cross_jump_death_matters
&& stack_regs_mentioned (i1
))
2996 /* If register stack conversion has already been done, then
2997 death notes must also be compared before it is certain that
2998 the two instruction streams match. */
3001 HARD_REG_SET i1_regset
, i2_regset
;
3003 CLEAR_HARD_REG_SET (i1_regset
);
3004 CLEAR_HARD_REG_SET (i2_regset
);
3006 for (note
= REG_NOTES (i1
); note
; note
= XEXP (note
, 1))
3007 if (REG_NOTE_KIND (note
) == REG_DEAD
3008 && STACK_REG_P (XEXP (note
, 0)))
3009 SET_HARD_REG_BIT (i1_regset
, REGNO (XEXP (note
, 0)));
3011 for (note
= REG_NOTES (i2
); note
; note
= XEXP (note
, 1))
3012 if (REG_NOTE_KIND (note
) == REG_DEAD
3013 && STACK_REG_P (XEXP (note
, 0)))
3014 SET_HARD_REG_BIT (i2_regset
, REGNO (XEXP (note
, 0)));
3016 GO_IF_HARD_REG_EQUAL (i1_regset
, i2_regset
, done
);
3025 /* Don't allow old-style asm or volatile extended asms to be accepted
3026 for cross jumping purposes. It is conceptually correct to allow
3027 them, since cross-jumping preserves the dynamic instruction order
3028 even though it is changing the static instruction order. However,
3029 if an asm is being used to emit an assembler pseudo-op, such as
3030 the MIPS `.set reorder' pseudo-op, then the static instruction order
3031 matters and it must be preserved. */
3032 if (GET_CODE (p1
) == ASM_INPUT
|| GET_CODE (p2
) == ASM_INPUT
3033 || (GET_CODE (p1
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p1
))
3034 || (GET_CODE (p2
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p2
)))
3037 if (lose
|| GET_CODE (p1
) != GET_CODE (p2
)
3038 || ! rtx_renumbered_equal_p (p1
, p2
))
3040 /* The following code helps take care of G++ cleanups. */
3044 if (!lose
&& GET_CODE (p1
) == GET_CODE (p2
)
3045 && ((equiv1
= find_reg_note (i1
, REG_EQUAL
, NULL_RTX
)) != 0
3046 || (equiv1
= find_reg_note (i1
, REG_EQUIV
, NULL_RTX
)) != 0)
3047 && ((equiv2
= find_reg_note (i2
, REG_EQUAL
, NULL_RTX
)) != 0
3048 || (equiv2
= find_reg_note (i2
, REG_EQUIV
, NULL_RTX
)) != 0)
3049 /* If the equivalences are not to a constant, they may
3050 reference pseudos that no longer exist, so we can't
3052 && CONSTANT_P (XEXP (equiv1
, 0))
3053 && rtx_equal_p (XEXP (equiv1
, 0), XEXP (equiv2
, 0)))
3055 rtx s1
= single_set (i1
);
3056 rtx s2
= single_set (i2
);
3057 if (s1
!= 0 && s2
!= 0
3058 && rtx_renumbered_equal_p (SET_DEST (s1
), SET_DEST (s2
)))
3060 validate_change (i1
, &SET_SRC (s1
), XEXP (equiv1
, 0), 1);
3061 validate_change (i2
, &SET_SRC (s2
), XEXP (equiv2
, 0), 1);
3062 if (! rtx_renumbered_equal_p (p1
, p2
))
3064 else if (apply_change_group ())
3069 /* Insns fail to match; cross jumping is limited to the following
3073 /* Don't allow the insn after a compare to be shared by
3074 cross-jumping unless the compare is also shared.
3075 Here, if either of these non-matching insns is a compare,
3076 exclude the following insn from possible cross-jumping. */
3077 if (sets_cc0_p (p1
) || sets_cc0_p (p2
))
3078 last1
= afterlast1
, last2
= afterlast2
, ++minimum
;
3081 /* If cross-jumping here will feed a jump-around-jump
3082 optimization, this jump won't cost extra, so reduce
3084 if (GET_CODE (i1
) == JUMP_INSN
3086 && prev_real_insn (JUMP_LABEL (i1
)) == e1
)
3092 if (GET_CODE (p1
) != USE
&& GET_CODE (p1
) != CLOBBER
)
3094 /* Ok, this insn is potentially includable in a cross-jump here. */
3095 afterlast1
= last1
, afterlast2
= last2
;
3096 last1
= i1
, last2
= i2
, --minimum
;
3100 if (minimum
<= 0 && last1
!= 0 && last1
!= e1
)
3101 *f1
= last1
, *f2
= last2
;
3105 do_cross_jump (insn
, newjpos
, newlpos
)
3106 rtx insn
, newjpos
, newlpos
;
3108 /* Find an existing label at this point
3109 or make a new one if there is none. */
3110 register rtx label
= get_label_before (newlpos
);
3112 /* Make the same jump insn jump to the new point. */
3113 if (GET_CODE (PATTERN (insn
)) == RETURN
)
3115 /* Remove from jump chain of returns. */
3116 delete_from_jump_chain (insn
);
3117 /* Change the insn. */
3118 PATTERN (insn
) = gen_jump (label
);
3119 INSN_CODE (insn
) = -1;
3120 JUMP_LABEL (insn
) = label
;
3121 LABEL_NUSES (label
)++;
3122 /* Add to new the jump chain. */
3123 if (INSN_UID (label
) < max_jump_chain
3124 && INSN_UID (insn
) < max_jump_chain
)
3126 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (label
)];
3127 jump_chain
[INSN_UID (label
)] = insn
;
3131 redirect_jump (insn
, label
);
3133 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
3134 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
3135 the NEWJPOS stream. */
3137 while (newjpos
!= insn
)
3141 for (lnote
= REG_NOTES (newlpos
); lnote
; lnote
= XEXP (lnote
, 1))
3142 if ((REG_NOTE_KIND (lnote
) == REG_EQUAL
3143 || REG_NOTE_KIND (lnote
) == REG_EQUIV
)
3144 && ! find_reg_note (newjpos
, REG_EQUAL
, XEXP (lnote
, 0))
3145 && ! find_reg_note (newjpos
, REG_EQUIV
, XEXP (lnote
, 0)))
3146 remove_note (newlpos
, lnote
);
3148 delete_insn (newjpos
);
3149 newjpos
= next_real_insn (newjpos
);
3150 newlpos
= next_real_insn (newlpos
);
3154 /* Return the label before INSN, or put a new label there. */
3157 get_label_before (insn
)
3162 /* Find an existing label at this point
3163 or make a new one if there is none. */
3164 label
= prev_nonnote_insn (insn
);
3166 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
3168 rtx prev
= PREV_INSN (insn
);
3170 label
= gen_label_rtx ();
3171 emit_label_after (label
, prev
);
3172 LABEL_NUSES (label
) = 0;
3177 /* Return the label after INSN, or put a new label there. */
3180 get_label_after (insn
)
3185 /* Find an existing label at this point
3186 or make a new one if there is none. */
3187 label
= next_nonnote_insn (insn
);
3189 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
3191 label
= gen_label_rtx ();
3192 emit_label_after (label
, insn
);
3193 LABEL_NUSES (label
) = 0;
3198 /* Return 1 if INSN is a jump that jumps to right after TARGET
3199 only on the condition that TARGET itself would drop through.
3200 Assumes that TARGET is a conditional jump. */
3203 jump_back_p (insn
, target
)
3207 enum rtx_code codei
, codet
;
3209 if (simplejump_p (insn
) || ! condjump_p (insn
)
3210 || simplejump_p (target
)
3211 || target
!= prev_real_insn (JUMP_LABEL (insn
)))
3214 cinsn
= XEXP (SET_SRC (PATTERN (insn
)), 0);
3215 ctarget
= XEXP (SET_SRC (PATTERN (target
)), 0);
3217 codei
= GET_CODE (cinsn
);
3218 codet
= GET_CODE (ctarget
);
3220 if (XEXP (SET_SRC (PATTERN (insn
)), 1) == pc_rtx
)
3222 if (! can_reverse_comparison_p (cinsn
, insn
))
3224 codei
= reverse_condition (codei
);
3227 if (XEXP (SET_SRC (PATTERN (target
)), 2) == pc_rtx
)
3229 if (! can_reverse_comparison_p (ctarget
, target
))
3231 codet
= reverse_condition (codet
);
3234 return (codei
== codet
3235 && rtx_renumbered_equal_p (XEXP (cinsn
, 0), XEXP (ctarget
, 0))
3236 && rtx_renumbered_equal_p (XEXP (cinsn
, 1), XEXP (ctarget
, 1)));
3239 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
3240 return non-zero if it is safe to reverse this comparison. It is if our
3241 floating-point is not IEEE, if this is an NE or EQ comparison, or if
3242 this is known to be an integer comparison. */
3245 can_reverse_comparison_p (comparison
, insn
)
3251 /* If this is not actually a comparison, we can't reverse it. */
3252 if (GET_RTX_CLASS (GET_CODE (comparison
)) != '<')
3255 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
3256 /* If this is an NE comparison, it is safe to reverse it to an EQ
3257 comparison and vice versa, even for floating point. If no operands
3258 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
3259 always false and NE is always true, so the reversal is also valid. */
3261 || GET_CODE (comparison
) == NE
3262 || GET_CODE (comparison
) == EQ
)
3265 arg0
= XEXP (comparison
, 0);
3267 /* Make sure ARG0 is one of the actual objects being compared. If we
3268 can't do this, we can't be sure the comparison can be reversed.
3270 Handle cc0 and a MODE_CC register. */
3271 if ((GET_CODE (arg0
) == REG
&& GET_MODE_CLASS (GET_MODE (arg0
)) == MODE_CC
)
3277 rtx prev
= prev_nonnote_insn (insn
);
3280 /* First see if the condition code mode alone if enough to say we can
3281 reverse the condition. If not, then search backwards for a set of
3282 ARG0. We do not need to check for an insn clobbering it since valid
3283 code will contain set a set with no intervening clobber. But
3284 stop when we reach a label. */
3285 #ifdef REVERSIBLE_CC_MODE
3286 if (GET_MODE_CLASS (GET_MODE (arg0
)) == MODE_CC
3287 && REVERSIBLE_CC_MODE (GET_MODE (arg0
)))
3291 for (prev
= prev_nonnote_insn (insn
);
3292 prev
!= 0 && GET_CODE (prev
) != CODE_LABEL
;
3293 prev
= prev_nonnote_insn (prev
))
3294 if ((set
= single_set (prev
)) != 0
3295 && rtx_equal_p (SET_DEST (set
), arg0
))
3297 arg0
= SET_SRC (set
);
3299 if (GET_CODE (arg0
) == COMPARE
)
3300 arg0
= XEXP (arg0
, 0);
3305 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
3306 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
3307 return (GET_CODE (arg0
) == CONST_INT
3308 || (GET_MODE (arg0
) != VOIDmode
3309 && GET_MODE_CLASS (GET_MODE (arg0
)) != MODE_CC
3310 && GET_MODE_CLASS (GET_MODE (arg0
)) != MODE_FLOAT
));
3313 /* Given an rtx-code for a comparison, return the code for the negated
3314 comparison. If no such code exists, return UNKNOWN.
3316 WATCH OUT! reverse_condition is not safe to use on a jump that might
3317 be acting on the results of an IEEE floating point comparison, because
3318 of the special treatment of non-signaling nans in comparisons.
3319 Use can_reverse_comparison_p to be sure. */
3322 reverse_condition (code
)
3365 /* Similar, but we're allowed to generate unordered comparisons, which
3366 makes it safe for IEEE floating-point. Of course, we have to recognize
3367 that the target will support them too... */
3370 reverse_condition_maybe_unordered (code
)
3373 /* Non-IEEE formats don't have unordered conditions. */
3374 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
)
3375 return reverse_condition (code
);
3421 /* Similar, but return the code when two operands of a comparison are swapped.
3422 This IS safe for IEEE floating-point. */
3425 swap_condition (code
)
3468 /* Given a comparison CODE, return the corresponding unsigned comparison.
3469 If CODE is an equality comparison or already an unsigned comparison,
3470 CODE is returned. */
3473 unsigned_condition (code
)
3500 /* Similarly, return the signed version of a comparison. */
3503 signed_condition (code
)
3530 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
3531 truth of CODE1 implies the truth of CODE2. */
3534 comparison_dominates_p (code1
, code2
)
3535 enum rtx_code code1
, code2
;
3543 if (code2
== LE
|| code2
== LEU
|| code2
== GE
|| code2
== GEU
3544 || code2
== ORDERED
)
3549 if (code2
== LE
|| code2
== NE
|| code2
== ORDERED
)
3554 if (code2
== GE
|| code2
== NE
|| code2
== ORDERED
)
3560 if (code2
== ORDERED
)
3565 if (code2
== NE
|| code2
== ORDERED
)
3570 if (code2
== LEU
|| code2
== NE
)
3575 if (code2
== GEU
|| code2
== NE
)
3591 /* Return 1 if INSN is an unconditional jump and nothing else. */
3597 return (GET_CODE (insn
) == JUMP_INSN
3598 && GET_CODE (PATTERN (insn
)) == SET
3599 && GET_CODE (SET_DEST (PATTERN (insn
))) == PC
3600 && GET_CODE (SET_SRC (PATTERN (insn
))) == LABEL_REF
);
3603 /* Return nonzero if INSN is a (possibly) conditional jump
3604 and nothing more. */
3610 register rtx x
= PATTERN (insn
);
3612 if (GET_CODE (x
) != SET
3613 || GET_CODE (SET_DEST (x
)) != PC
)
3617 if (GET_CODE (x
) == LABEL_REF
)
3619 else return (GET_CODE (x
) == IF_THEN_ELSE
3620 && ((GET_CODE (XEXP (x
, 2)) == PC
3621 && (GET_CODE (XEXP (x
, 1)) == LABEL_REF
3622 || GET_CODE (XEXP (x
, 1)) == RETURN
))
3623 || (GET_CODE (XEXP (x
, 1)) == PC
3624 && (GET_CODE (XEXP (x
, 2)) == LABEL_REF
3625 || GET_CODE (XEXP (x
, 2)) == RETURN
))));
3630 /* Return nonzero if INSN is a (possibly) conditional jump inside a
3634 condjump_in_parallel_p (insn
)
3637 register rtx x
= PATTERN (insn
);
3639 if (GET_CODE (x
) != PARALLEL
)
3642 x
= XVECEXP (x
, 0, 0);
3644 if (GET_CODE (x
) != SET
)
3646 if (GET_CODE (SET_DEST (x
)) != PC
)
3648 if (GET_CODE (SET_SRC (x
)) == LABEL_REF
)
3650 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
3652 if (XEXP (SET_SRC (x
), 2) == pc_rtx
3653 && (GET_CODE (XEXP (SET_SRC (x
), 1)) == LABEL_REF
3654 || GET_CODE (XEXP (SET_SRC (x
), 1)) == RETURN
))
3656 if (XEXP (SET_SRC (x
), 1) == pc_rtx
3657 && (GET_CODE (XEXP (SET_SRC (x
), 2)) == LABEL_REF
3658 || GET_CODE (XEXP (SET_SRC (x
), 2)) == RETURN
))
3663 /* Return the label of a conditional jump. */
3666 condjump_label (insn
)
3669 register rtx x
= PATTERN (insn
);
3671 if (GET_CODE (x
) == PARALLEL
)
3672 x
= XVECEXP (x
, 0, 0);
3673 if (GET_CODE (x
) != SET
)
3675 if (GET_CODE (SET_DEST (x
)) != PC
)
3678 if (GET_CODE (x
) == LABEL_REF
)
3680 if (GET_CODE (x
) != IF_THEN_ELSE
)
3682 if (XEXP (x
, 2) == pc_rtx
&& GET_CODE (XEXP (x
, 1)) == LABEL_REF
)
3684 if (XEXP (x
, 1) == pc_rtx
&& GET_CODE (XEXP (x
, 2)) == LABEL_REF
)
3689 /* Return true if INSN is a (possibly conditional) return insn. */
3692 returnjump_p_1 (loc
, data
)
3694 void *data ATTRIBUTE_UNUSED
;
3697 return x
&& GET_CODE (x
) == RETURN
;
3704 return for_each_rtx (&PATTERN (insn
), returnjump_p_1
, NULL
);
3707 /* Return true if INSN is a jump that only transfers control and
3716 if (GET_CODE (insn
) != JUMP_INSN
)
3719 set
= single_set (insn
);
3722 if (GET_CODE (SET_DEST (set
)) != PC
)
3724 if (side_effects_p (SET_SRC (set
)))
3732 /* Return 1 if X is an RTX that does nothing but set the condition codes
3733 and CLOBBER or USE registers.
3734 Return -1 if X does explicitly set the condition codes,
3735 but also does other things. */
3739 rtx x ATTRIBUTE_UNUSED
;
3741 if (GET_CODE (x
) == SET
&& SET_DEST (x
) == cc0_rtx
)
3743 if (GET_CODE (x
) == PARALLEL
)
3747 int other_things
= 0;
3748 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
3750 if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
3751 && SET_DEST (XVECEXP (x
, 0, i
)) == cc0_rtx
)
3753 else if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
)
3756 return ! sets_cc0
? 0 : other_things
? -1 : 1;
3762 /* Follow any unconditional jump at LABEL;
3763 return the ultimate label reached by any such chain of jumps.
3764 If LABEL is not followed by a jump, return LABEL.
3765 If the chain loops or we can't find end, return LABEL,
3766 since that tells caller to avoid changing the insn.
3768 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
3769 a USE or CLOBBER. */
3772 follow_jumps (label
)
3777 register rtx value
= label
;
3782 && (insn
= next_active_insn (value
)) != 0
3783 && GET_CODE (insn
) == JUMP_INSN
3784 && ((JUMP_LABEL (insn
) != 0 && simplejump_p (insn
))
3785 || GET_CODE (PATTERN (insn
)) == RETURN
)
3786 && (next
= NEXT_INSN (insn
))
3787 && GET_CODE (next
) == BARRIER
);
3790 /* Don't chain through the insn that jumps into a loop
3791 from outside the loop,
3792 since that would create multiple loop entry jumps
3793 and prevent loop optimization. */
3795 if (!reload_completed
)
3796 for (tem
= value
; tem
!= insn
; tem
= NEXT_INSN (tem
))
3797 if (GET_CODE (tem
) == NOTE
3798 && (NOTE_LINE_NUMBER (tem
) == NOTE_INSN_LOOP_BEG
3799 /* ??? Optional. Disables some optimizations, but makes
3800 gcov output more accurate with -O. */
3801 || (flag_test_coverage
&& NOTE_LINE_NUMBER (tem
) > 0)))
3804 /* If we have found a cycle, make the insn jump to itself. */
3805 if (JUMP_LABEL (insn
) == label
)
3808 tem
= next_active_insn (JUMP_LABEL (insn
));
3809 if (tem
&& (GET_CODE (PATTERN (tem
)) == ADDR_VEC
3810 || GET_CODE (PATTERN (tem
)) == ADDR_DIFF_VEC
))
3813 value
= JUMP_LABEL (insn
);
3820 /* Assuming that field IDX of X is a vector of label_refs,
3821 replace each of them by the ultimate label reached by it.
3822 Return nonzero if a change is made.
3823 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
3826 tension_vector_labels (x
, idx
)
3832 for (i
= XVECLEN (x
, idx
) - 1; i
>= 0; i
--)
3834 register rtx olabel
= XEXP (XVECEXP (x
, idx
, i
), 0);
3835 register rtx nlabel
= follow_jumps (olabel
);
3836 if (nlabel
&& nlabel
!= olabel
)
3838 XEXP (XVECEXP (x
, idx
, i
), 0) = nlabel
;
3839 ++LABEL_NUSES (nlabel
);
3840 if (--LABEL_NUSES (olabel
) == 0)
3841 delete_insn (olabel
);
3848 /* Find all CODE_LABELs referred to in X, and increment their use counts.
3849 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
3850 in INSN, then store one of them in JUMP_LABEL (INSN).
3851 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
3852 referenced in INSN, add a REG_LABEL note containing that label to INSN.
3853 Also, when there are consecutive labels, canonicalize on the last of them.
3855 Note that two labels separated by a loop-beginning note
3856 must be kept distinct if we have not yet done loop-optimization,
3857 because the gap between them is where loop-optimize
3858 will want to move invariant code to. CROSS_JUMP tells us
3859 that loop-optimization is done with.
3861 Once reload has completed (CROSS_JUMP non-zero), we need not consider
3862 two labels distinct if they are separated by only USE or CLOBBER insns. */
3865 mark_jump_label (x
, insn
, cross_jump
)
3870 register RTX_CODE code
= GET_CODE (x
);
3872 register const char *fmt
;
3888 /* If this is a constant-pool reference, see if it is a label. */
3889 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3890 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3891 mark_jump_label (get_pool_constant (XEXP (x
, 0)), insn
, cross_jump
);
3896 rtx label
= XEXP (x
, 0);
3901 if (GET_CODE (label
) != CODE_LABEL
)
3904 /* Ignore references to labels of containing functions. */
3905 if (LABEL_REF_NONLOCAL_P (x
))
3908 /* If there are other labels following this one,
3909 replace it with the last of the consecutive labels. */
3910 for (next
= NEXT_INSN (label
); next
; next
= NEXT_INSN (next
))
3912 if (GET_CODE (next
) == CODE_LABEL
)
3914 else if (cross_jump
&& GET_CODE (next
) == INSN
3915 && (GET_CODE (PATTERN (next
)) == USE
3916 || GET_CODE (PATTERN (next
)) == CLOBBER
))
3918 else if (GET_CODE (next
) != NOTE
)
3920 else if (! cross_jump
3921 && (NOTE_LINE_NUMBER (next
) == NOTE_INSN_LOOP_BEG
3922 || NOTE_LINE_NUMBER (next
) == NOTE_INSN_FUNCTION_END
3923 /* ??? Optional. Disables some optimizations, but
3924 makes gcov output more accurate with -O. */
3925 || (flag_test_coverage
&& NOTE_LINE_NUMBER (next
) > 0)))
3929 XEXP (x
, 0) = label
;
3930 if (! insn
|| ! INSN_DELETED_P (insn
))
3931 ++LABEL_NUSES (label
);
3935 if (GET_CODE (insn
) == JUMP_INSN
)
3936 JUMP_LABEL (insn
) = label
;
3938 /* If we've changed OLABEL and we had a REG_LABEL note
3939 for it, update it as well. */
3940 else if (label
!= olabel
3941 && (note
= find_reg_note (insn
, REG_LABEL
, olabel
)) != 0)
3942 XEXP (note
, 0) = label
;
3944 /* Otherwise, add a REG_LABEL note for LABEL unless there already
3946 else if (! find_reg_note (insn
, REG_LABEL
, label
))
3948 /* This code used to ignore labels which refered to dispatch
3949 tables to avoid flow.c generating worse code.
3951 However, in the presense of global optimizations like
3952 gcse which call find_basic_blocks without calling
3953 life_analysis, not recording such labels will lead
3954 to compiler aborts because of inconsistencies in the
3955 flow graph. So we go ahead and record the label.
3957 It may also be the case that the optimization argument
3958 is no longer valid because of the more accurate cfg
3959 we build in find_basic_blocks -- it no longer pessimizes
3960 code when it finds a REG_LABEL note. */
3961 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_LABEL
, label
,
3968 /* Do walk the labels in a vector, but not the first operand of an
3969 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
3972 if (! INSN_DELETED_P (insn
))
3974 int eltnum
= code
== ADDR_DIFF_VEC
? 1 : 0;
3976 for (i
= 0; i
< XVECLEN (x
, eltnum
); i
++)
3977 mark_jump_label (XVECEXP (x
, eltnum
, i
), NULL_RTX
, cross_jump
);
3985 fmt
= GET_RTX_FORMAT (code
);
3986 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3989 mark_jump_label (XEXP (x
, i
), insn
, cross_jump
);
3990 else if (fmt
[i
] == 'E')
3993 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3994 mark_jump_label (XVECEXP (x
, i
, j
), insn
, cross_jump
);
3999 /* If all INSN does is set the pc, delete it,
4000 and delete the insn that set the condition codes for it
4001 if that's what the previous thing was. */
4007 register rtx set
= single_set (insn
);
4009 if (set
&& GET_CODE (SET_DEST (set
)) == PC
)
4010 delete_computation (insn
);
4013 /* Verify INSN is a BARRIER and delete it. */
4016 delete_barrier (insn
)
4019 if (GET_CODE (insn
) != BARRIER
)
4025 /* Recursively delete prior insns that compute the value (used only by INSN
4026 which the caller is deleting) stored in the register mentioned by NOTE
4027 which is a REG_DEAD note associated with INSN. */
4030 delete_prior_computation (note
, insn
)
4035 rtx reg
= XEXP (note
, 0);
4037 for (our_prev
= prev_nonnote_insn (insn
);
4038 our_prev
&& (GET_CODE (our_prev
) == INSN
4039 || GET_CODE (our_prev
) == CALL_INSN
);
4040 our_prev
= prev_nonnote_insn (our_prev
))
4042 rtx pat
= PATTERN (our_prev
);
4044 /* If we reach a CALL which is not calling a const function
4045 or the callee pops the arguments, then give up. */
4046 if (GET_CODE (our_prev
) == CALL_INSN
4047 && (! CONST_CALL_P (our_prev
)
4048 || GET_CODE (pat
) != SET
|| GET_CODE (SET_SRC (pat
)) != CALL
))
4051 /* If we reach a SEQUENCE, it is too complex to try to
4052 do anything with it, so give up. */
4053 if (GET_CODE (pat
) == SEQUENCE
)
4056 if (GET_CODE (pat
) == USE
4057 && GET_CODE (XEXP (pat
, 0)) == INSN
)
4058 /* reorg creates USEs that look like this. We leave them
4059 alone because reorg needs them for its own purposes. */
4062 if (reg_set_p (reg
, pat
))
4064 if (side_effects_p (pat
) && GET_CODE (our_prev
) != CALL_INSN
)
4067 if (GET_CODE (pat
) == PARALLEL
)
4069 /* If we find a SET of something else, we can't
4074 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
4076 rtx part
= XVECEXP (pat
, 0, i
);
4078 if (GET_CODE (part
) == SET
4079 && SET_DEST (part
) != reg
)
4083 if (i
== XVECLEN (pat
, 0))
4084 delete_computation (our_prev
);
4086 else if (GET_CODE (pat
) == SET
4087 && GET_CODE (SET_DEST (pat
)) == REG
)
4089 int dest_regno
= REGNO (SET_DEST (pat
));
4091 = dest_regno
+ (dest_regno
< FIRST_PSEUDO_REGISTER
4092 ? HARD_REGNO_NREGS (dest_regno
,
4093 GET_MODE (SET_DEST (pat
))) : 1);
4094 int regno
= REGNO (reg
);
4095 int endregno
= regno
+ (regno
< FIRST_PSEUDO_REGISTER
4096 ? HARD_REGNO_NREGS (regno
, GET_MODE (reg
)) : 1);
4098 if (dest_regno
>= regno
4099 && dest_endregno
<= endregno
)
4100 delete_computation (our_prev
);
4102 /* We may have a multi-word hard register and some, but not
4103 all, of the words of the register are needed in subsequent
4104 insns. Write REG_UNUSED notes for those parts that were not
4106 else if (dest_regno
<= regno
4107 && dest_endregno
>= endregno
)
4111 REG_NOTES (our_prev
)
4112 = gen_rtx_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (our_prev
));
4114 for (i
= dest_regno
; i
< dest_endregno
; i
++)
4115 if (! find_regno_note (our_prev
, REG_UNUSED
, i
))
4118 if (i
== dest_endregno
)
4119 delete_computation (our_prev
);
4126 /* If PAT references the register that dies here, it is an
4127 additional use. Hence any prior SET isn't dead. However, this
4128 insn becomes the new place for the REG_DEAD note. */
4129 if (reg_overlap_mentioned_p (reg
, pat
))
4131 XEXP (note
, 1) = REG_NOTES (our_prev
);
4132 REG_NOTES (our_prev
) = note
;
4138 /* Delete INSN and recursively delete insns that compute values used only
4139 by INSN. This uses the REG_DEAD notes computed during flow analysis.
4140 If we are running before flow.c, we need do nothing since flow.c will
4141 delete dead code. We also can't know if the registers being used are
4142 dead or not at this point.
4144 Otherwise, look at all our REG_DEAD notes. If a previous insn does
4145 nothing other than set a register that dies in this insn, we can delete
4148 On machines with CC0, if CC0 is used in this insn, we may be able to
4149 delete the insn that set it. */
4152 delete_computation (insn
)
4159 if (reg_referenced_p (cc0_rtx
, PATTERN (insn
)))
4161 rtx prev
= prev_nonnote_insn (insn
);
4162 /* We assume that at this stage
4163 CC's are always set explicitly
4164 and always immediately before the jump that
4165 will use them. So if the previous insn
4166 exists to set the CC's, delete it
4167 (unless it performs auto-increments, etc.). */
4168 if (prev
&& GET_CODE (prev
) == INSN
4169 && sets_cc0_p (PATTERN (prev
)))
4171 if (sets_cc0_p (PATTERN (prev
)) > 0
4172 && ! side_effects_p (PATTERN (prev
)))
4173 delete_computation (prev
);
4175 /* Otherwise, show that cc0 won't be used. */
4176 REG_NOTES (prev
) = gen_rtx_EXPR_LIST (REG_UNUSED
,
4177 cc0_rtx
, REG_NOTES (prev
));
4182 #ifdef INSN_SCHEDULING
4183 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
4184 reload has completed. The schedulers need to be fixed. Until
4185 they are, we must not rely on the death notes here. */
4186 if (reload_completed
&& flag_schedule_insns_after_reload
)
4193 /* The REG_DEAD note may have been omitted for a register
4194 which is both set and used by the insn. */
4195 set
= single_set (insn
);
4196 if (set
&& GET_CODE (SET_DEST (set
)) == REG
)
4198 int dest_regno
= REGNO (SET_DEST (set
));
4200 = dest_regno
+ (dest_regno
< FIRST_PSEUDO_REGISTER
4201 ? HARD_REGNO_NREGS (dest_regno
,
4202 GET_MODE (SET_DEST (set
))) : 1);
4205 for (i
= dest_regno
; i
< dest_endregno
; i
++)
4207 if (! refers_to_regno_p (i
, i
+ 1, SET_SRC (set
), NULL_PTR
)
4208 || find_regno_note (insn
, REG_DEAD
, i
))
4211 note
= gen_rtx_EXPR_LIST (REG_DEAD
, (i
< FIRST_PSEUDO_REGISTER
4212 ? gen_rtx_REG (reg_raw_mode
[i
], i
)
4213 : SET_DEST (set
)), NULL_RTX
);
4214 delete_prior_computation (note
, insn
);
4218 for (note
= REG_NOTES (insn
); note
; note
= next
)
4220 next
= XEXP (note
, 1);
4222 if (REG_NOTE_KIND (note
) != REG_DEAD
4223 /* Verify that the REG_NOTE is legitimate. */
4224 || GET_CODE (XEXP (note
, 0)) != REG
)
4227 delete_prior_computation (note
, insn
);
4233 /* Delete insn INSN from the chain of insns and update label ref counts.
4234 May delete some following insns as a consequence; may even delete
4235 a label elsewhere and insns that follow it.
4237 Returns the first insn after INSN that was not deleted. */
4243 register rtx next
= NEXT_INSN (insn
);
4244 register rtx prev
= PREV_INSN (insn
);
4245 register int was_code_label
= (GET_CODE (insn
) == CODE_LABEL
);
4246 register int dont_really_delete
= 0;
4248 while (next
&& INSN_DELETED_P (next
))
4249 next
= NEXT_INSN (next
);
4251 /* This insn is already deleted => return first following nondeleted. */
4252 if (INSN_DELETED_P (insn
))
4256 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
4258 /* Don't delete user-declared labels. Convert them to special NOTEs
4260 if (was_code_label
&& LABEL_NAME (insn
) != 0
4261 && optimize
&& ! dont_really_delete
)
4263 PUT_CODE (insn
, NOTE
);
4264 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED_LABEL
;
4265 NOTE_SOURCE_FILE (insn
) = 0;
4266 dont_really_delete
= 1;
4269 /* Mark this insn as deleted. */
4270 INSN_DELETED_P (insn
) = 1;
4272 /* If this is an unconditional jump, delete it from the jump chain. */
4273 if (simplejump_p (insn
))
4274 delete_from_jump_chain (insn
);
4276 /* If instruction is followed by a barrier,
4277 delete the barrier too. */
4279 if (next
!= 0 && GET_CODE (next
) == BARRIER
)
4281 INSN_DELETED_P (next
) = 1;
4282 next
= NEXT_INSN (next
);
4285 /* Patch out INSN (and the barrier if any) */
4287 if (! dont_really_delete
)
4291 NEXT_INSN (prev
) = next
;
4292 if (GET_CODE (prev
) == INSN
&& GET_CODE (PATTERN (prev
)) == SEQUENCE
)
4293 NEXT_INSN (XVECEXP (PATTERN (prev
), 0,
4294 XVECLEN (PATTERN (prev
), 0) - 1)) = next
;
4299 PREV_INSN (next
) = prev
;
4300 if (GET_CODE (next
) == INSN
&& GET_CODE (PATTERN (next
)) == SEQUENCE
)
4301 PREV_INSN (XVECEXP (PATTERN (next
), 0, 0)) = prev
;
4304 if (prev
&& NEXT_INSN (prev
) == 0)
4305 set_last_insn (prev
);
4308 /* If deleting a jump, decrement the count of the label,
4309 and delete the label if it is now unused. */
4311 if (GET_CODE (insn
) == JUMP_INSN
&& JUMP_LABEL (insn
))
4313 rtx lab
= JUMP_LABEL (insn
), lab_next
;
4315 if (--LABEL_NUSES (lab
) == 0)
4317 /* This can delete NEXT or PREV,
4318 either directly if NEXT is JUMP_LABEL (INSN),
4319 or indirectly through more levels of jumps. */
4322 /* I feel a little doubtful about this loop,
4323 but I see no clean and sure alternative way
4324 to find the first insn after INSN that is not now deleted.
4325 I hope this works. */
4326 while (next
&& INSN_DELETED_P (next
))
4327 next
= NEXT_INSN (next
);
4330 else if ((lab_next
= next_nonnote_insn (lab
)) != NULL
4331 && GET_CODE (lab_next
) == JUMP_INSN
4332 && (GET_CODE (PATTERN (lab_next
)) == ADDR_VEC
4333 || GET_CODE (PATTERN (lab_next
)) == ADDR_DIFF_VEC
))
4335 /* If we're deleting the tablejump, delete the dispatch table.
4336 We may not be able to kill the label immediately preceeding
4337 just yet, as it might be referenced in code leading up to
4339 delete_insn (lab_next
);
4343 /* Likewise if we're deleting a dispatch table. */
4345 if (GET_CODE (insn
) == JUMP_INSN
4346 && (GET_CODE (PATTERN (insn
)) == ADDR_VEC
4347 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
))
4349 rtx pat
= PATTERN (insn
);
4350 int i
, diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
4351 int len
= XVECLEN (pat
, diff_vec_p
);
4353 for (i
= 0; i
< len
; i
++)
4354 if (--LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)) == 0)
4355 delete_insn (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0));
4356 while (next
&& INSN_DELETED_P (next
))
4357 next
= NEXT_INSN (next
);
4361 while (prev
&& (INSN_DELETED_P (prev
) || GET_CODE (prev
) == NOTE
))
4362 prev
= PREV_INSN (prev
);
4364 /* If INSN was a label and a dispatch table follows it,
4365 delete the dispatch table. The tablejump must have gone already.
4366 It isn't useful to fall through into a table. */
4369 && NEXT_INSN (insn
) != 0
4370 && GET_CODE (NEXT_INSN (insn
)) == JUMP_INSN
4371 && (GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_VEC
4372 || GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_DIFF_VEC
))
4373 next
= delete_insn (NEXT_INSN (insn
));
4375 /* If INSN was a label, delete insns following it if now unreachable. */
4377 if (was_code_label
&& prev
&& GET_CODE (prev
) == BARRIER
)
4379 register RTX_CODE code
;
4381 && (GET_RTX_CLASS (code
= GET_CODE (next
)) == 'i'
4382 || code
== NOTE
|| code
== BARRIER
4383 || (code
== CODE_LABEL
&& INSN_DELETED_P (next
))))
4386 && NOTE_LINE_NUMBER (next
) != NOTE_INSN_FUNCTION_END
)
4387 next
= NEXT_INSN (next
);
4388 /* Keep going past other deleted labels to delete what follows. */
4389 else if (code
== CODE_LABEL
&& INSN_DELETED_P (next
))
4390 next
= NEXT_INSN (next
);
4392 /* Note: if this deletes a jump, it can cause more
4393 deletion of unreachable code, after a different label.
4394 As long as the value from this recursive call is correct,
4395 this invocation functions correctly. */
4396 next
= delete_insn (next
);
4403 /* Advance from INSN till reaching something not deleted
4404 then return that. May return INSN itself. */
4407 next_nondeleted_insn (insn
)
4410 while (INSN_DELETED_P (insn
))
4411 insn
= NEXT_INSN (insn
);
4415 /* Delete a range of insns from FROM to TO, inclusive.
4416 This is for the sake of peephole optimization, so assume
4417 that whatever these insns do will still be done by a new
4418 peephole insn that will replace them. */
4421 delete_for_peephole (from
, to
)
4422 register rtx from
, to
;
4424 register rtx insn
= from
;
4428 register rtx next
= NEXT_INSN (insn
);
4429 register rtx prev
= PREV_INSN (insn
);
4431 if (GET_CODE (insn
) != NOTE
)
4433 INSN_DELETED_P (insn
) = 1;
4435 /* Patch this insn out of the chain. */
4436 /* We don't do this all at once, because we
4437 must preserve all NOTEs. */
4439 NEXT_INSN (prev
) = next
;
4442 PREV_INSN (next
) = prev
;
4450 /* Note that if TO is an unconditional jump
4451 we *do not* delete the BARRIER that follows,
4452 since the peephole that replaces this sequence
4453 is also an unconditional jump in that case. */
4456 /* We have determined that INSN is never reached, and are about to
4457 delete it. Print a warning if the user asked for one.
4459 To try to make this warning more useful, this should only be called
4460 once per basic block not reached, and it only warns when the basic
4461 block contains more than one line from the current function, and
4462 contains at least one operation. CSE and inlining can duplicate insns,
4463 so it's possible to get spurious warnings from this. */
4466 never_reached_warning (avoided_insn
)
4470 rtx a_line_note
= NULL
;
4471 int two_avoided_lines
= 0;
4472 int contains_insn
= 0;
4474 if (! warn_notreached
)
4477 /* Scan forwards, looking at LINE_NUMBER notes, until
4478 we hit a LABEL or we run out of insns. */
4480 for (insn
= avoided_insn
; insn
!= NULL
; insn
= NEXT_INSN (insn
))
4482 if (GET_CODE (insn
) == CODE_LABEL
)
4484 else if (GET_CODE (insn
) == NOTE
/* A line number note? */
4485 && NOTE_LINE_NUMBER (insn
) >= 0)
4487 if (a_line_note
== NULL
)
4490 two_avoided_lines
|= (NOTE_LINE_NUMBER (a_line_note
)
4491 != NOTE_LINE_NUMBER (insn
));
4493 else if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
4496 if (two_avoided_lines
&& contains_insn
)
4497 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note
),
4498 NOTE_LINE_NUMBER (a_line_note
),
4499 "will never be executed");
4502 /* Invert the condition of the jump JUMP, and make it jump
4503 to label NLABEL instead of where it jumps now. */
4506 invert_jump (jump
, nlabel
)
4509 /* We have to either invert the condition and change the label or
4510 do neither. Either operation could fail. We first try to invert
4511 the jump. If that succeeds, we try changing the label. If that fails,
4512 we invert the jump back to what it was. */
4514 if (! invert_exp (PATTERN (jump
), jump
))
4517 if (redirect_jump (jump
, nlabel
))
4519 if (flag_branch_probabilities
)
4521 rtx note
= find_reg_note (jump
, REG_BR_PROB
, 0);
4523 /* An inverted jump means that a probability taken becomes a
4524 probability not taken. Subtract the branch probability from the
4525 probability base to convert it back to a taken probability.
4526 (We don't flip the probability on a branch that's never taken. */
4527 if (note
&& XINT (XEXP (note
, 0), 0) >= 0)
4528 XINT (XEXP (note
, 0), 0) = REG_BR_PROB_BASE
- XINT (XEXP (note
, 0), 0);
4534 if (! invert_exp (PATTERN (jump
), jump
))
4535 /* This should just be putting it back the way it was. */
4541 /* Invert the jump condition of rtx X contained in jump insn, INSN.
4543 Return 1 if we can do so, 0 if we cannot find a way to do so that
4544 matches a pattern. */
4547 invert_exp (x
, insn
)
4551 register RTX_CODE code
;
4553 register const char *fmt
;
4555 code
= GET_CODE (x
);
4557 if (code
== IF_THEN_ELSE
)
4559 register rtx comp
= XEXP (x
, 0);
4562 /* We can do this in two ways: The preferable way, which can only
4563 be done if this is not an integer comparison, is to reverse
4564 the comparison code. Otherwise, swap the THEN-part and ELSE-part
4565 of the IF_THEN_ELSE. If we can't do either, fail. */
4567 if (can_reverse_comparison_p (comp
, insn
)
4568 && validate_change (insn
, &XEXP (x
, 0),
4569 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp
)),
4570 GET_MODE (comp
), XEXP (comp
, 0),
4571 XEXP (comp
, 1)), 0))
4575 validate_change (insn
, &XEXP (x
, 1), XEXP (x
, 2), 1);
4576 validate_change (insn
, &XEXP (x
, 2), tem
, 1);
4577 return apply_change_group ();
4580 fmt
= GET_RTX_FORMAT (code
);
4581 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4585 if (! invert_exp (XEXP (x
, i
), insn
))
4588 else if (fmt
[i
] == 'E')
4591 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4592 if (!invert_exp (XVECEXP (x
, i
, j
), insn
))
4600 /* Make jump JUMP jump to label NLABEL instead of where it jumps now.
4601 If the old jump target label is unused as a result,
4602 it and the code following it may be deleted.
4604 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
4607 The return value will be 1 if the change was made, 0 if it wasn't (this
4608 can only occur for NLABEL == 0). */
4611 redirect_jump (jump
, nlabel
)
4614 register rtx olabel
= JUMP_LABEL (jump
);
4616 if (nlabel
== olabel
)
4619 if (! redirect_exp (&PATTERN (jump
), olabel
, nlabel
, jump
))
4622 /* If this is an unconditional branch, delete it from the jump_chain of
4623 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
4624 have UID's in range and JUMP_CHAIN is valid). */
4625 if (jump_chain
&& (simplejump_p (jump
)
4626 || GET_CODE (PATTERN (jump
)) == RETURN
))
4628 int label_index
= nlabel
? INSN_UID (nlabel
) : 0;
4630 delete_from_jump_chain (jump
);
4631 if (label_index
< max_jump_chain
4632 && INSN_UID (jump
) < max_jump_chain
)
4634 jump_chain
[INSN_UID (jump
)] = jump_chain
[label_index
];
4635 jump_chain
[label_index
] = jump
;
4639 JUMP_LABEL (jump
) = nlabel
;
4641 ++LABEL_NUSES (nlabel
);
4643 /* If we're eliding the jump over exception cleanups at the end of a
4644 function, move the function end note so that -Wreturn-type works. */
4645 if (olabel
&& NEXT_INSN (olabel
)
4646 && GET_CODE (NEXT_INSN (olabel
)) == NOTE
4647 && NOTE_LINE_NUMBER (NEXT_INSN (olabel
)) == NOTE_INSN_FUNCTION_END
)
4648 emit_note_after (NOTE_INSN_FUNCTION_END
, nlabel
);
4650 if (olabel
&& --LABEL_NUSES (olabel
) == 0)
4651 delete_insn (olabel
);
4656 /* Delete the instruction JUMP from any jump chain it might be on. */
4659 delete_from_jump_chain (jump
)
4663 rtx olabel
= JUMP_LABEL (jump
);
4665 /* Handle unconditional jumps. */
4666 if (jump_chain
&& olabel
!= 0
4667 && INSN_UID (olabel
) < max_jump_chain
4668 && simplejump_p (jump
))
4669 index
= INSN_UID (olabel
);
4670 /* Handle return insns. */
4671 else if (jump_chain
&& GET_CODE (PATTERN (jump
)) == RETURN
)
4675 if (jump_chain
[index
] == jump
)
4676 jump_chain
[index
] = jump_chain
[INSN_UID (jump
)];
4681 for (insn
= jump_chain
[index
];
4683 insn
= jump_chain
[INSN_UID (insn
)])
4684 if (jump_chain
[INSN_UID (insn
)] == jump
)
4686 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (jump
)];
4692 /* If NLABEL is nonzero, throughout the rtx at LOC,
4693 alter (LABEL_REF OLABEL) to (LABEL_REF NLABEL). If OLABEL is
4694 zero, alter (RETURN) to (LABEL_REF NLABEL).
4696 If NLABEL is zero, alter (LABEL_REF OLABEL) to (RETURN) and check
4697 validity with validate_change. Convert (set (pc) (label_ref olabel))
4700 Return 0 if we found a change we would like to make but it is invalid.
4701 Otherwise, return 1. */
4704 redirect_exp (loc
, olabel
, nlabel
, insn
)
4709 register rtx x
= *loc
;
4710 register RTX_CODE code
= GET_CODE (x
);
4712 register const char *fmt
;
4714 if (code
== LABEL_REF
)
4716 if (XEXP (x
, 0) == olabel
)
4719 XEXP (x
, 0) = nlabel
;
4721 return validate_change (insn
, loc
, gen_rtx_RETURN (VOIDmode
), 0);
4725 else if (code
== RETURN
&& olabel
== 0)
4727 x
= gen_rtx_LABEL_REF (VOIDmode
, nlabel
);
4728 if (loc
== &PATTERN (insn
))
4729 x
= gen_rtx_SET (VOIDmode
, pc_rtx
, x
);
4730 return validate_change (insn
, loc
, x
, 0);
4733 if (code
== SET
&& nlabel
== 0 && SET_DEST (x
) == pc_rtx
4734 && GET_CODE (SET_SRC (x
)) == LABEL_REF
4735 && XEXP (SET_SRC (x
), 0) == olabel
)
4736 return validate_change (insn
, loc
, gen_rtx_RETURN (VOIDmode
), 0);
4738 fmt
= GET_RTX_FORMAT (code
);
4739 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4743 if (! redirect_exp (&XEXP (x
, i
), olabel
, nlabel
, insn
))
4746 else if (fmt
[i
] == 'E')
4749 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4750 if (! redirect_exp (&XVECEXP (x
, i
, j
), olabel
, nlabel
, insn
))
4758 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
4760 If the old jump target label (before the dispatch table) becomes unused,
4761 it and the dispatch table may be deleted. In that case, find the insn
4762 before the jump references that label and delete it and logical successors
4766 redirect_tablejump (jump
, nlabel
)
4769 register rtx olabel
= JUMP_LABEL (jump
);
4771 /* Add this jump to the jump_chain of NLABEL. */
4772 if (jump_chain
&& INSN_UID (nlabel
) < max_jump_chain
4773 && INSN_UID (jump
) < max_jump_chain
)
4775 jump_chain
[INSN_UID (jump
)] = jump_chain
[INSN_UID (nlabel
)];
4776 jump_chain
[INSN_UID (nlabel
)] = jump
;
4779 PATTERN (jump
) = gen_jump (nlabel
);
4780 JUMP_LABEL (jump
) = nlabel
;
4781 ++LABEL_NUSES (nlabel
);
4782 INSN_CODE (jump
) = -1;
4784 if (--LABEL_NUSES (olabel
) == 0)
4786 delete_labelref_insn (jump
, olabel
, 0);
4787 delete_insn (olabel
);
4791 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
4792 If we found one, delete it and then delete this insn if DELETE_THIS is
4793 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
4796 delete_labelref_insn (insn
, label
, delete_this
)
4803 if (GET_CODE (insn
) != NOTE
4804 && reg_mentioned_p (label
, PATTERN (insn
)))
4815 for (link
= LOG_LINKS (insn
); link
; link
= XEXP (link
, 1))
4816 if (delete_labelref_insn (XEXP (link
, 0), label
, 1))
4830 /* Like rtx_equal_p except that it considers two REGs as equal
4831 if they renumber to the same value and considers two commutative
4832 operations to be the same if the order of the operands has been
4835 ??? Addition is not commutative on the PA due to the weird implicit
4836 space register selection rules for memory addresses. Therefore, we
4837 don't consider a + b == b + a.
4839 We could/should make this test a little tighter. Possibly only
4840 disabling it on the PA via some backend macro or only disabling this
4841 case when the PLUS is inside a MEM. */
4844 rtx_renumbered_equal_p (x
, y
)
4848 register RTX_CODE code
= GET_CODE (x
);
4849 register const char *fmt
;
4854 if ((code
== REG
|| (code
== SUBREG
&& GET_CODE (SUBREG_REG (x
)) == REG
))
4855 && (GET_CODE (y
) == REG
|| (GET_CODE (y
) == SUBREG
4856 && GET_CODE (SUBREG_REG (y
)) == REG
)))
4858 int reg_x
= -1, reg_y
= -1;
4859 int word_x
= 0, word_y
= 0;
4861 if (GET_MODE (x
) != GET_MODE (y
))
4864 /* If we haven't done any renumbering, don't
4865 make any assumptions. */
4866 if (reg_renumber
== 0)
4867 return rtx_equal_p (x
, y
);
4871 reg_x
= REGNO (SUBREG_REG (x
));
4872 word_x
= SUBREG_WORD (x
);
4874 if (reg_renumber
[reg_x
] >= 0)
4876 reg_x
= reg_renumber
[reg_x
] + word_x
;
4884 if (reg_renumber
[reg_x
] >= 0)
4885 reg_x
= reg_renumber
[reg_x
];
4888 if (GET_CODE (y
) == SUBREG
)
4890 reg_y
= REGNO (SUBREG_REG (y
));
4891 word_y
= SUBREG_WORD (y
);
4893 if (reg_renumber
[reg_y
] >= 0)
4895 reg_y
= reg_renumber
[reg_y
];
4903 if (reg_renumber
[reg_y
] >= 0)
4904 reg_y
= reg_renumber
[reg_y
];
4907 return reg_x
>= 0 && reg_x
== reg_y
&& word_x
== word_y
;
4910 /* Now we have disposed of all the cases
4911 in which different rtx codes can match. */
4912 if (code
!= GET_CODE (y
))
4924 return INTVAL (x
) == INTVAL (y
);
4927 /* We can't assume nonlocal labels have their following insns yet. */
4928 if (LABEL_REF_NONLOCAL_P (x
) || LABEL_REF_NONLOCAL_P (y
))
4929 return XEXP (x
, 0) == XEXP (y
, 0);
4931 /* Two label-refs are equivalent if they point at labels
4932 in the same position in the instruction stream. */
4933 return (next_real_insn (XEXP (x
, 0))
4934 == next_real_insn (XEXP (y
, 0)));
4937 return XSTR (x
, 0) == XSTR (y
, 0);
4940 /* If we didn't match EQ equality above, they aren't the same. */
4947 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
4949 if (GET_MODE (x
) != GET_MODE (y
))
4952 /* For commutative operations, the RTX match if the operand match in any
4953 order. Also handle the simple binary and unary cases without a loop.
4955 ??? Don't consider PLUS a commutative operator; see comments above. */
4956 if ((code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
4958 return ((rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
4959 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)))
4960 || (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 1))
4961 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 0))));
4962 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
4963 return (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
4964 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)));
4965 else if (GET_RTX_CLASS (code
) == '1')
4966 return rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0));
4968 /* Compare the elements. If any pair of corresponding elements
4969 fail to match, return 0 for the whole things. */
4971 fmt
= GET_RTX_FORMAT (code
);
4972 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4978 if (XWINT (x
, i
) != XWINT (y
, i
))
4983 if (XINT (x
, i
) != XINT (y
, i
))
4988 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
4993 if (! rtx_renumbered_equal_p (XEXP (x
, i
), XEXP (y
, i
)))
4998 if (XEXP (x
, i
) != XEXP (y
, i
))
5005 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
5007 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
5008 if (!rtx_renumbered_equal_p (XVECEXP (x
, i
, j
), XVECEXP (y
, i
, j
)))
5019 /* If X is a hard register or equivalent to one or a subregister of one,
5020 return the hard register number. If X is a pseudo register that was not
5021 assigned a hard register, return the pseudo register number. Otherwise,
5022 return -1. Any rtx is valid for X. */
5028 if (GET_CODE (x
) == REG
)
5030 if (REGNO (x
) >= FIRST_PSEUDO_REGISTER
&& reg_renumber
[REGNO (x
)] >= 0)
5031 return reg_renumber
[REGNO (x
)];
5034 if (GET_CODE (x
) == SUBREG
)
5036 int base
= true_regnum (SUBREG_REG (x
));
5037 if (base
>= 0 && base
< FIRST_PSEUDO_REGISTER
)
5038 return SUBREG_WORD (x
) + base
;
5043 /* Optimize code of the form:
5045 for (x = a[i]; x; ...)
5047 for (x = a[i]; x; ...)
5051 Loop optimize will change the above code into
5055 { ...; if (! (x = ...)) break; }
5058 { ...; if (! (x = ...)) break; }
5061 In general, if the first test fails, the program can branch
5062 directly to `foo' and skip the second try which is doomed to fail.
5063 We run this after loop optimization and before flow analysis. */
5065 /* When comparing the insn patterns, we track the fact that different
5066 pseudo-register numbers may have been used in each computation.
5067 The following array stores an equivalence -- same_regs[I] == J means
5068 that pseudo register I was used in the first set of tests in a context
5069 where J was used in the second set. We also count the number of such
5070 pending equivalences. If nonzero, the expressions really aren't the
5073 static int *same_regs
;
5075 static int num_same_regs
;
5077 /* Track any registers modified between the target of the first jump and
5078 the second jump. They never compare equal. */
5080 static char *modified_regs
;
5082 /* Record if memory was modified. */
5084 static int modified_mem
;
5086 /* Called via note_stores on each insn between the target of the first
5087 branch and the second branch. It marks any changed registers. */
5090 mark_modified_reg (dest
, x
, data
)
5092 rtx x ATTRIBUTE_UNUSED
;
5093 void *data ATTRIBUTE_UNUSED
;
5097 if (GET_CODE (dest
) == SUBREG
)
5098 dest
= SUBREG_REG (dest
);
5100 if (GET_CODE (dest
) == MEM
)
5103 if (GET_CODE (dest
) != REG
)
5106 regno
= REGNO (dest
);
5107 if (regno
>= FIRST_PSEUDO_REGISTER
)
5108 modified_regs
[regno
] = 1;
5110 for (i
= 0; i
< HARD_REGNO_NREGS (regno
, GET_MODE (dest
)); i
++)
5111 modified_regs
[regno
+ i
] = 1;
5114 /* F is the first insn in the chain of insns. */
5117 thread_jumps (f
, max_reg
, flag_before_loop
)
5120 int flag_before_loop
;
5122 /* Basic algorithm is to find a conditional branch,
5123 the label it may branch to, and the branch after
5124 that label. If the two branches test the same condition,
5125 walk back from both branch paths until the insn patterns
5126 differ, or code labels are hit. If we make it back to
5127 the target of the first branch, then we know that the first branch
5128 will either always succeed or always fail depending on the relative
5129 senses of the two branches. So adjust the first branch accordingly
5132 rtx label
, b1
, b2
, t1
, t2
;
5133 enum rtx_code code1
, code2
;
5134 rtx b1op0
, b1op1
, b2op0
, b2op1
;
5139 /* Allocate register tables and quick-reset table. */
5140 modified_regs
= (char *) xmalloc (max_reg
* sizeof (char));
5141 same_regs
= (int *) xmalloc (max_reg
* sizeof (int));
5142 all_reset
= (int *) xmalloc (max_reg
* sizeof (int));
5143 for (i
= 0; i
< max_reg
; i
++)
5150 for (b1
= f
; b1
; b1
= NEXT_INSN (b1
))
5152 /* Get to a candidate branch insn. */
5153 if (GET_CODE (b1
) != JUMP_INSN
5154 || ! condjump_p (b1
) || simplejump_p (b1
)
5155 || JUMP_LABEL (b1
) == 0)
5158 bzero (modified_regs
, max_reg
* sizeof (char));
5161 bcopy ((char *) all_reset
, (char *) same_regs
,
5162 max_reg
* sizeof (int));
5165 label
= JUMP_LABEL (b1
);
5167 /* Look for a branch after the target. Record any registers and
5168 memory modified between the target and the branch. Stop when we
5169 get to a label since we can't know what was changed there. */
5170 for (b2
= NEXT_INSN (label
); b2
; b2
= NEXT_INSN (b2
))
5172 if (GET_CODE (b2
) == CODE_LABEL
)
5175 else if (GET_CODE (b2
) == JUMP_INSN
)
5177 /* If this is an unconditional jump and is the only use of
5178 its target label, we can follow it. */
5179 if (simplejump_p (b2
)
5180 && JUMP_LABEL (b2
) != 0
5181 && LABEL_NUSES (JUMP_LABEL (b2
)) == 1)
5183 b2
= JUMP_LABEL (b2
);
5190 if (GET_CODE (b2
) != CALL_INSN
&& GET_CODE (b2
) != INSN
)
5193 if (GET_CODE (b2
) == CALL_INSN
)
5196 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
5197 if (call_used_regs
[i
] && ! fixed_regs
[i
]
5198 && i
!= STACK_POINTER_REGNUM
5199 && i
!= FRAME_POINTER_REGNUM
5200 && i
!= HARD_FRAME_POINTER_REGNUM
5201 && i
!= ARG_POINTER_REGNUM
)
5202 modified_regs
[i
] = 1;
5205 note_stores (PATTERN (b2
), mark_modified_reg
, NULL
);
5208 /* Check the next candidate branch insn from the label
5211 || GET_CODE (b2
) != JUMP_INSN
5213 || ! condjump_p (b2
)
5214 || simplejump_p (b2
))
5217 /* Get the comparison codes and operands, reversing the
5218 codes if appropriate. If we don't have comparison codes,
5219 we can't do anything. */
5220 b1op0
= XEXP (XEXP (SET_SRC (PATTERN (b1
)), 0), 0);
5221 b1op1
= XEXP (XEXP (SET_SRC (PATTERN (b1
)), 0), 1);
5222 code1
= GET_CODE (XEXP (SET_SRC (PATTERN (b1
)), 0));
5223 if (XEXP (SET_SRC (PATTERN (b1
)), 1) == pc_rtx
)
5224 code1
= reverse_condition (code1
);
5226 b2op0
= XEXP (XEXP (SET_SRC (PATTERN (b2
)), 0), 0);
5227 b2op1
= XEXP (XEXP (SET_SRC (PATTERN (b2
)), 0), 1);
5228 code2
= GET_CODE (XEXP (SET_SRC (PATTERN (b2
)), 0));
5229 if (XEXP (SET_SRC (PATTERN (b2
)), 1) == pc_rtx
)
5230 code2
= reverse_condition (code2
);
5232 /* If they test the same things and knowing that B1 branches
5233 tells us whether or not B2 branches, check if we
5234 can thread the branch. */
5235 if (rtx_equal_for_thread_p (b1op0
, b2op0
, b2
)
5236 && rtx_equal_for_thread_p (b1op1
, b2op1
, b2
)
5237 && (comparison_dominates_p (code1
, code2
)
5238 || (can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1
)),
5241 && comparison_dominates_p (code1
, reverse_condition (code2
)))))
5244 t1
= prev_nonnote_insn (b1
);
5245 t2
= prev_nonnote_insn (b2
);
5247 while (t1
!= 0 && t2
!= 0)
5251 /* We have reached the target of the first branch.
5252 If there are no pending register equivalents,
5253 we know that this branch will either always
5254 succeed (if the senses of the two branches are
5255 the same) or always fail (if not). */
5258 if (num_same_regs
!= 0)
5261 if (comparison_dominates_p (code1
, code2
))
5262 new_label
= JUMP_LABEL (b2
);
5264 new_label
= get_label_after (b2
);
5266 if (JUMP_LABEL (b1
) != new_label
)
5268 rtx prev
= PREV_INSN (new_label
);
5270 if (flag_before_loop
5271 && GET_CODE (prev
) == NOTE
5272 && NOTE_LINE_NUMBER (prev
) == NOTE_INSN_LOOP_BEG
)
5274 /* Don't thread to the loop label. If a loop
5275 label is reused, loop optimization will
5276 be disabled for that loop. */
5277 new_label
= gen_label_rtx ();
5278 emit_label_after (new_label
, PREV_INSN (prev
));
5280 changed
|= redirect_jump (b1
, new_label
);
5285 /* If either of these is not a normal insn (it might be
5286 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
5287 have already been skipped above.) Similarly, fail
5288 if the insns are different. */
5289 if (GET_CODE (t1
) != INSN
|| GET_CODE (t2
) != INSN
5290 || recog_memoized (t1
) != recog_memoized (t2
)
5291 || ! rtx_equal_for_thread_p (PATTERN (t1
),
5295 t1
= prev_nonnote_insn (t1
);
5296 t2
= prev_nonnote_insn (t2
);
5303 free (modified_regs
);
5308 /* This is like RTX_EQUAL_P except that it knows about our handling of
5309 possibly equivalent registers and knows to consider volatile and
5310 modified objects as not equal.
5312 YINSN is the insn containing Y. */
5315 rtx_equal_for_thread_p (x
, y
, yinsn
)
5321 register enum rtx_code code
;
5322 register const char *fmt
;
5324 code
= GET_CODE (x
);
5325 /* Rtx's of different codes cannot be equal. */
5326 if (code
!= GET_CODE (y
))
5329 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
5330 (REG:SI x) and (REG:HI x) are NOT equivalent. */
5332 if (GET_MODE (x
) != GET_MODE (y
))
5335 /* For floating-point, consider everything unequal. This is a bit
5336 pessimistic, but this pass would only rarely do anything for FP
5338 if (TARGET_FLOAT_FORMAT
== IEEE_FLOAT_FORMAT
5339 && FLOAT_MODE_P (GET_MODE (x
)) && ! flag_fast_math
)
5342 /* For commutative operations, the RTX match if the operand match in any
5343 order. Also handle the simple binary and unary cases without a loop. */
5344 if (code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
5345 return ((rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
5346 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
))
5347 || (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 1), yinsn
)
5348 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 0), yinsn
)));
5349 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
5350 return (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
5351 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
));
5352 else if (GET_RTX_CLASS (code
) == '1')
5353 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
5355 /* Handle special-cases first. */
5359 if (REGNO (x
) == REGNO (y
) && ! modified_regs
[REGNO (x
)])
5362 /* If neither is user variable or hard register, check for possible
5364 if (REG_USERVAR_P (x
) || REG_USERVAR_P (y
)
5365 || REGNO (x
) < FIRST_PSEUDO_REGISTER
5366 || REGNO (y
) < FIRST_PSEUDO_REGISTER
)
5369 if (same_regs
[REGNO (x
)] == -1)
5371 same_regs
[REGNO (x
)] = REGNO (y
);
5374 /* If this is the first time we are seeing a register on the `Y'
5375 side, see if it is the last use. If not, we can't thread the
5376 jump, so mark it as not equivalent. */
5377 if (REGNO_LAST_UID (REGNO (y
)) != INSN_UID (yinsn
))
5383 return (same_regs
[REGNO (x
)] == REGNO (y
));
5388 /* If memory modified or either volatile, not equivalent.
5389 Else, check address. */
5390 if (modified_mem
|| MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
5393 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
5396 if (MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
5402 /* Cancel a pending `same_regs' if setting equivalenced registers.
5403 Then process source. */
5404 if (GET_CODE (SET_DEST (x
)) == REG
5405 && GET_CODE (SET_DEST (y
)) == REG
)
5407 if (same_regs
[REGNO (SET_DEST (x
))] == REGNO (SET_DEST (y
)))
5409 same_regs
[REGNO (SET_DEST (x
))] = -1;
5412 else if (REGNO (SET_DEST (x
)) != REGNO (SET_DEST (y
)))
5416 if (rtx_equal_for_thread_p (SET_DEST (x
), SET_DEST (y
), yinsn
) == 0)
5419 return rtx_equal_for_thread_p (SET_SRC (x
), SET_SRC (y
), yinsn
);
5422 return XEXP (x
, 0) == XEXP (y
, 0);
5425 return XSTR (x
, 0) == XSTR (y
, 0);
5434 fmt
= GET_RTX_FORMAT (code
);
5435 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
5440 if (XWINT (x
, i
) != XWINT (y
, i
))
5446 if (XINT (x
, i
) != XINT (y
, i
))
5452 /* Two vectors must have the same length. */
5453 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
5456 /* And the corresponding elements must match. */
5457 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
5458 if (rtx_equal_for_thread_p (XVECEXP (x
, i
, j
),
5459 XVECEXP (y
, i
, j
), yinsn
) == 0)
5464 if (rtx_equal_for_thread_p (XEXP (x
, i
), XEXP (y
, i
), yinsn
) == 0)
5470 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
5475 /* These are just backpointers, so they don't matter. */
5482 /* It is believed that rtx's at this level will never
5483 contain anything but integers and other rtx's,
5484 except for within LABEL_REFs and SYMBOL_REFs. */
5493 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
5494 /* Return the insn that NEW can be safely inserted in front of starting at
5495 the jump insn INSN. Return 0 if it is not safe to do this jump
5496 optimization. Note that NEW must contain a single set. */
5499 find_insert_position (insn
, new)
5506 /* If NEW does not clobber, it is safe to insert NEW before INSN. */
5507 if (GET_CODE (PATTERN (new)) != PARALLEL
)
5510 for (i
= XVECLEN (PATTERN (new), 0) - 1; i
>= 0; i
--)
5511 if (GET_CODE (XVECEXP (PATTERN (new), 0, i
)) == CLOBBER
5512 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i
), 0),
5519 /* There is a good chance that the previous insn PREV sets the thing
5520 being clobbered (often the CC in a hard reg). If PREV does not
5521 use what NEW sets, we can insert NEW before PREV. */
5523 prev
= prev_active_insn (insn
);
5524 for (i
= XVECLEN (PATTERN (new), 0) - 1; i
>= 0; i
--)
5525 if (GET_CODE (XVECEXP (PATTERN (new), 0, i
)) == CLOBBER
5526 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i
), 0),
5528 && ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i
), 0),
5532 return reg_mentioned_p (SET_DEST (single_set (new)), prev
) ? 0 : prev
;
5534 #endif /* !HAVE_cc0 */