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 /* Look for if (foo) bar; else break; */
1999 /* The insns look like this:
2000 insn = condjump label1;
2001 ...range1 (some insns)...
2004 ...range2 (some insns)...
2005 jump somewhere unconditionally
2008 rtx label1 = next_label (insn);
2009 rtx range1end = label1 ? prev_active_insn (label1) : 0;
2010 /* Don't do this optimization on the first round, so that
2011 jump-around-a-jump gets simplified before we ask here
2012 whether a jump is unconditional.
2014 Also don't do it when we are called after reload since
2015 it will confuse reorg. */
2017 && (reload_completed ? ! flag_delayed_branch : 1)
2018 /* Make sure INSN is something we can invert. */
2019 && condjump_p (insn)
2021 && JUMP_LABEL (insn) == label1
2022 && LABEL_NUSES (label1) == 1
2023 && GET_CODE (range1end) == JUMP_INSN
2024 && simplejump_p (range1end))
2026 rtx label2 = next_label (label1);
2027 rtx range2end = label2 ? prev_active_insn (label2) : 0;
2028 if (range1end != range2end
2029 && JUMP_LABEL (range1end) == label2
2030 && GET_CODE (range2end) == JUMP_INSN
2031 && GET_CODE (NEXT_INSN (range2end)) == BARRIER
2032 /* Invert the jump condition, so we
2033 still execute the same insns in each case. */
2034 && invert_jump (insn, label1))
2036 rtx range1beg = next_active_insn (insn);
2037 rtx range2beg = next_active_insn (label1);
2038 rtx range1after, range2after;
2039 rtx range1before, range2before;
2042 /* Include in each range any notes before it, to be
2043 sure that we get the line number note if any, even
2044 if there are other notes here. */
2045 while (PREV_INSN (range1beg)
2046 && GET_CODE (PREV_INSN (range1beg)) == NOTE)
2047 range1beg = PREV_INSN (range1beg);
2049 while (PREV_INSN (range2beg)
2050 && GET_CODE (PREV_INSN (range2beg)) == NOTE)
2051 range2beg = PREV_INSN (range2beg);
2053 /* Don't move NOTEs for blocks or loops; shift them
2054 outside the ranges, where they'll stay put. */
2055 range1beg = squeeze_notes (range1beg, range1end);
2056 range2beg = squeeze_notes (range2beg, range2end);
2058 /* Get current surrounds of the 2 ranges. */
2059 range1before = PREV_INSN (range1beg);
2060 range2before = PREV_INSN (range2beg);
2061 range1after = NEXT_INSN (range1end);
2062 range2after = NEXT_INSN (range2end);
2064 /* Splice range2 where range1 was. */
2065 NEXT_INSN (range1before) = range2beg;
2066 PREV_INSN (range2beg) = range1before;
2067 NEXT_INSN (range2end) = range1after;
2068 PREV_INSN (range1after) = range2end;
2069 /* Splice range1 where range2 was. */
2070 NEXT_INSN (range2before) = range1beg;
2071 PREV_INSN (range1beg) = range2before;
2072 NEXT_INSN (range1end) = range2after;
2073 PREV_INSN (range2after) = range1end;
2075 /* Check for loop notes between the end of
2076 range2, and the next code label. If there is one,
2077 then what we have really seen is
2078 if (foo) break; end_of_loop;
2079 and moved the break sequence outside the loop.
2080 We must move LOOP_END, LOOP_VTOP and LOOP_CONT
2081 notes (in order) to where the loop really ends now,
2082 or we will confuse loop optimization. Stop if we
2083 find a LOOP_BEG note first, since we don't want to
2084 move the notes in that case. */
2085 for (;range2after != label2; range2after = rangenext)
2087 rangenext = NEXT_INSN (range2after);
2088 if (GET_CODE (range2after) == NOTE)
2090 int kind = NOTE_LINE_NUMBER (range2after);
2091 if (kind == NOTE_INSN_LOOP_END
2092 || kind == NOTE_INSN_LOOP_VTOP
2093 || kind == NOTE_INSN_LOOP_CONT)
2095 NEXT_INSN (PREV_INSN (range2after))
2097 PREV_INSN (rangenext)
2098 = PREV_INSN (range2after);
2099 PREV_INSN (range2after)
2100 = PREV_INSN (range1beg);
2101 NEXT_INSN (range2after) = range1beg;
2102 NEXT_INSN (PREV_INSN (range1beg))
2104 PREV_INSN (range1beg) = range2after;
2106 else if (NOTE_LINE_NUMBER (range2after)
2107 == NOTE_INSN_LOOP_BEG)
2117 /* Now that the jump has been tensioned,
2118 try cross jumping: check for identical code
2119 before the jump and before its target label. */
2121 /* First, cross jumping of conditional jumps: */
2123 if (cross_jump && condjump_p (insn))
2125 rtx newjpos, newlpos;
2126 rtx x = prev_real_insn (JUMP_LABEL (insn));
2128 /* A conditional jump may be crossjumped
2129 only if the place it jumps to follows
2130 an opposing jump that comes back here. */
2132 if (x != 0 && ! jump_back_p (x, insn))
2133 /* We have no opposing jump;
2134 cannot cross jump this insn. */
2138 /* TARGET is nonzero if it is ok to cross jump
2139 to code before TARGET. If so, see if matches. */
2141 find_cross_jump (insn, x, 2,
2142 &newjpos, &newlpos);
2146 do_cross_jump (insn, newjpos, newlpos);
2147 /* Make the old conditional jump
2148 into an unconditional one. */
2149 SET_SRC (PATTERN (insn))
2150 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
2151 INSN_CODE (insn) = -1;
2152 emit_barrier_after (insn);
2153 /* Add to jump_chain unless this is a new label
2154 whose UID is too large. */
2155 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
2157 jump_chain[INSN_UID (insn)]
2158 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2159 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2166 /* Cross jumping of unconditional jumps:
2167 a few differences. */
2169 if (cross_jump && simplejump_p (insn))
2171 rtx newjpos, newlpos;
2176 /* TARGET is nonzero if it is ok to cross jump
2177 to code before TARGET. If so, see if matches. */
2178 find_cross_jump (insn, JUMP_LABEL (insn), 1,
2179 &newjpos, &newlpos);
2181 /* If cannot cross jump to code before the label,
2182 see if we can cross jump to another jump to
2184 /* Try each other jump to this label. */
2185 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
2186 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2187 target != 0 && newjpos == 0;
2188 target = jump_chain[INSN_UID (target)])
2190 && JUMP_LABEL (target) == JUMP_LABEL (insn)
2191 /* Ignore TARGET if it's deleted. */
2192 && ! INSN_DELETED_P (target))
2193 find_cross_jump (insn, target, 2,
2194 &newjpos, &newlpos);
2198 do_cross_jump (insn, newjpos, newlpos);
2204 /* This code was dead in the previous jump.c! */
2205 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
2207 /* Return insns all "jump to the same place"
2208 so we can cross-jump between any two of them. */
2210 rtx newjpos, newlpos, target;
2214 /* If cannot cross jump to code before the label,
2215 see if we can cross jump to another jump to
2217 /* Try each other jump to this label. */
2218 for (target = jump_chain[0];
2219 target != 0 && newjpos == 0;
2220 target = jump_chain[INSN_UID (target)])
2222 && ! INSN_DELETED_P (target)
2223 && GET_CODE (PATTERN (target)) == RETURN)
2224 find_cross_jump (insn, target, 2,
2225 &newjpos, &newlpos);
2229 do_cross_jump (insn, newjpos, newlpos);
2240 /* Delete extraneous line number notes.
2241 Note that two consecutive notes for different lines are not really
2242 extraneous. There should be some indication where that line belonged,
2243 even if it became empty. */
2248 for (insn = f; insn; insn = NEXT_INSN (insn))
2249 if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
2251 /* Delete this note if it is identical to previous note. */
2253 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
2254 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
2267 /* If we fall through to the epilogue, see if we can insert a RETURN insn
2268 in front of it. If the machine allows it at this point (we might be
2269 after reload for a leaf routine), it will improve optimization for it
2270 to be there. We do this both here and at the start of this pass since
2271 the RETURN might have been deleted by some of our optimizations. */
2272 insn = get_last_insn ();
2273 while (insn && GET_CODE (insn) == NOTE)
2274 insn = PREV_INSN (insn);
2276 if (insn && GET_CODE (insn) != BARRIER)
2278 emit_jump_insn (gen_return ());
2284 /* CAN_REACH_END is persistent for each function. Once set it should
2285 not be cleared. This is especially true for the case where we
2286 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
2287 the front-end before compiling each function. */
2288 if (calculate_can_reach_end (last_insn, optimize != 0))
2297 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
2298 notes whose labels don't occur in the insn any more. Returns the
2299 largest INSN_UID found. */
2304 int largest_uid = 0;
2307 for (insn = f; insn; insn = NEXT_INSN (insn))
2309 if (GET_CODE (insn) == CODE_LABEL)
2310 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
2311 else if (GET_CODE (insn) == JUMP_INSN)
2312 JUMP_LABEL (insn) = 0;
2313 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2317 for (note = REG_NOTES (insn); note; note = next)
2319 next = XEXP (note, 1);
2320 if (REG_NOTE_KIND (note) == REG_LABEL
2321 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
2322 remove_note (insn, note);
2325 if (INSN_UID (insn) > largest_uid)
2326 largest_uid = INSN_UID (insn);
2332 /* Delete insns following barriers, up to next label.
2334 Also delete no-op jumps created by gcse. */
2336 delete_barrier_successors (f)
2341 for (insn = f; insn;)
2343 if (GET_CODE (insn) == BARRIER)
2345 insn = NEXT_INSN (insn);
2347 never_reached_warning (insn);
2349 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
2351 if (GET_CODE (insn) == NOTE
2352 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2353 insn = NEXT_INSN (insn);
2355 insn = delete_insn (insn);
2357 /* INSN is now the code_label. */
2359 /* Also remove (set (pc) (pc)) insns which can be created by
2360 gcse. We eliminate such insns now to avoid having them
2361 cause problems later. */
2362 else if (GET_CODE (insn) == JUMP_INSN
2363 && GET_CODE (PATTERN (insn)) == SET
2364 && SET_SRC (PATTERN (insn)) == pc_rtx
2365 && SET_DEST (PATTERN (insn)) == pc_rtx)
2366 insn = delete_insn (insn);
2369 insn = NEXT_INSN (insn);
2373 /* Mark the label each jump jumps to.
2374 Combine consecutive labels, and count uses of labels.
2376 For each label, make a chain (using `jump_chain')
2377 of all the *unconditional* jumps that jump to it;
2378 also make a chain of all returns.
2380 CROSS_JUMP indicates whether we are doing cross jumping
2381 and if we are whether we will be paying attention to
2382 death notes or not. */
2385 mark_all_labels (f, cross_jump)
2391 for (insn = f; insn; insn = NEXT_INSN (insn))
2392 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
2394 mark_jump_label (PATTERN (insn), insn, cross_jump);
2395 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
2397 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
2399 jump_chain[INSN_UID (insn)]
2400 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2401 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2403 if (GET_CODE (PATTERN (insn)) == RETURN)
2405 jump_chain[INSN_UID (insn)] = jump_chain[0];
2406 jump_chain[0] = insn;
2412 /* Delete all labels already not referenced.
2413 Also find and return the last insn. */
2416 delete_unreferenced_labels (f)
2419 rtx final = NULL_RTX;
2422 for (insn = f; insn; )
2424 if (GET_CODE (insn) == CODE_LABEL
2425 && LABEL_NUSES (insn) == 0
2426 && LABEL_ALTERNATE_NAME (insn) == NULL)
2427 insn = delete_insn (insn);
2431 insn = NEXT_INSN (insn);
2438 /* Delete various simple forms of moves which have no necessary
2442 delete_noop_moves (f)
2447 for (insn = f; insn; )
2449 next = NEXT_INSN (insn);
2451 if (GET_CODE (insn) == INSN)
2453 register rtx body = PATTERN (insn);
2455 /* Combine stack_adjusts with following push_insns. */
2456 #ifdef PUSH_ROUNDING
2457 if (GET_CODE (body) == SET
2458 && SET_DEST (body) == stack_pointer_rtx
2459 && GET_CODE (SET_SRC (body)) == PLUS
2460 && XEXP (SET_SRC (body), 0) == stack_pointer_rtx
2461 && GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
2462 && INTVAL (XEXP (SET_SRC (body), 1)) > 0)
2465 rtx stack_adjust_insn = insn;
2466 int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
2467 int total_pushed = 0;
2470 /* Find all successive push insns. */
2472 /* Don't convert more than three pushes;
2473 that starts adding too many displaced addresses
2474 and the whole thing starts becoming a losing
2479 p = next_nonnote_insn (p);
2480 if (p == 0 || GET_CODE (p) != INSN)
2482 pbody = PATTERN (p);
2483 if (GET_CODE (pbody) != SET)
2485 dest = SET_DEST (pbody);
2486 /* Allow a no-op move between the adjust and the push. */
2487 if (GET_CODE (dest) == REG
2488 && GET_CODE (SET_SRC (pbody)) == REG
2489 && REGNO (dest) == REGNO (SET_SRC (pbody)))
2491 if (! (GET_CODE (dest) == MEM
2492 && GET_CODE (XEXP (dest, 0)) == POST_INC
2493 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
2496 if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
2497 > stack_adjust_amount)
2499 total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
2502 /* Discard the amount pushed from the stack adjust;
2503 maybe eliminate it entirely. */
2504 if (total_pushed >= stack_adjust_amount)
2506 delete_computation (stack_adjust_insn);
2507 total_pushed = stack_adjust_amount;
2510 XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
2511 = GEN_INT (stack_adjust_amount - total_pushed);
2513 /* Change the appropriate push insns to ordinary stores. */
2515 while (total_pushed > 0)
2518 p = next_nonnote_insn (p);
2519 if (GET_CODE (p) != INSN)
2521 pbody = PATTERN (p);
2522 if (GET_CODE (pbody) != SET)
2524 dest = SET_DEST (pbody);
2525 /* Allow a no-op move between the adjust and the push. */
2526 if (GET_CODE (dest) == REG
2527 && GET_CODE (SET_SRC (pbody)) == REG
2528 && REGNO (dest) == REGNO (SET_SRC (pbody)))
2530 if (! (GET_CODE (dest) == MEM
2531 && GET_CODE (XEXP (dest, 0)) == POST_INC
2532 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
2534 total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
2535 /* If this push doesn't fully fit in the space
2536 of the stack adjust that we deleted,
2537 make another stack adjust here for what we
2538 didn't use up. There should be peepholes
2539 to recognize the resulting sequence of insns. */
2540 if (total_pushed < 0)
2542 emit_insn_before (gen_add2_insn (stack_pointer_rtx,
2543 GEN_INT (- total_pushed)),
2548 = plus_constant (stack_pointer_rtx, total_pushed);
2553 /* Detect and delete no-op move instructions
2554 resulting from not allocating a parameter in a register. */
2556 if (GET_CODE (body) == SET
2557 && (SET_DEST (body) == SET_SRC (body)
2558 || (GET_CODE (SET_DEST (body)) == MEM
2559 && GET_CODE (SET_SRC (body)) == MEM
2560 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
2561 && ! (GET_CODE (SET_DEST (body)) == MEM
2562 && MEM_VOLATILE_P (SET_DEST (body)))
2563 && ! (GET_CODE (SET_SRC (body)) == MEM
2564 && MEM_VOLATILE_P (SET_SRC (body))))
2565 delete_computation (insn);
2567 /* Detect and ignore no-op move instructions
2568 resulting from smart or fortuitous register allocation. */
2570 else if (GET_CODE (body) == SET)
2572 int sreg = true_regnum (SET_SRC (body));
2573 int dreg = true_regnum (SET_DEST (body));
2575 if (sreg == dreg && sreg >= 0)
2577 else if (sreg >= 0 && dreg >= 0)
2580 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
2581 sreg, NULL_PTR, dreg,
2582 GET_MODE (SET_SRC (body)));
2585 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
2587 /* DREG may have been the target of a REG_DEAD note in
2588 the insn which makes INSN redundant. If so, reorg
2589 would still think it is dead. So search for such a
2590 note and delete it if we find it. */
2591 if (! find_regno_note (insn, REG_UNUSED, dreg))
2592 for (trial = prev_nonnote_insn (insn);
2593 trial && GET_CODE (trial) != CODE_LABEL;
2594 trial = prev_nonnote_insn (trial))
2595 if (find_regno_note (trial, REG_DEAD, dreg))
2597 remove_death (dreg, trial);
2601 /* Deleting insn could lose a death-note for SREG. */
2602 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
2604 /* Change this into a USE so that we won't emit
2605 code for it, but still can keep the note. */
2607 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
2608 INSN_CODE (insn) = -1;
2609 /* Remove all reg notes but the REG_DEAD one. */
2610 REG_NOTES (insn) = trial;
2611 XEXP (trial, 1) = NULL_RTX;
2617 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
2618 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
2620 GET_MODE (SET_DEST (body))))
2622 /* This handles the case where we have two consecutive
2623 assignments of the same constant to pseudos that didn't
2624 get a hard reg. Each SET from the constant will be
2625 converted into a SET of the spill register and an
2626 output reload will be made following it. This produces
2627 two loads of the same constant into the same spill
2632 /* Look back for a death note for the first reg.
2633 If there is one, it is no longer accurate. */
2634 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
2636 if ((GET_CODE (in_insn) == INSN
2637 || GET_CODE (in_insn) == JUMP_INSN)
2638 && find_regno_note (in_insn, REG_DEAD, dreg))
2640 remove_death (dreg, in_insn);
2643 in_insn = PREV_INSN (in_insn);
2646 /* Delete the second load of the value. */
2650 else if (GET_CODE (body) == PARALLEL)
2652 /* If each part is a set between two identical registers or
2653 a USE or CLOBBER, delete the insn. */
2657 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
2659 tem = XVECEXP (body, 0, i);
2660 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
2663 if (GET_CODE (tem) != SET
2664 || (sreg = true_regnum (SET_SRC (tem))) < 0
2665 || (dreg = true_regnum (SET_DEST (tem))) < 0
2673 /* Also delete insns to store bit fields if they are no-ops. */
2674 /* Not worth the hair to detect this in the big-endian case. */
2675 else if (! BYTES_BIG_ENDIAN
2676 && GET_CODE (body) == SET
2677 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
2678 && XEXP (SET_DEST (body), 2) == const0_rtx
2679 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
2680 && ! (GET_CODE (SET_SRC (body)) == MEM
2681 && MEM_VOLATILE_P (SET_SRC (body))))
2688 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
2689 If so indicate that this function can drop off the end by returning
2692 CHECK_DELETED indicates whether we must check if the note being
2693 searched for has the deleted flag set.
2695 DELETE_FINAL_NOTE indicates whether we should delete the note
2699 calculate_can_reach_end (last, delete_final_note)
2701 int delete_final_note;
2706 while (insn != NULL_RTX)
2710 /* One label can follow the end-note: the return label. */
2711 if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
2713 /* Ordinary insns can follow it if returning a structure. */
2714 else if (GET_CODE (insn) == INSN)
2716 /* If machine uses explicit RETURN insns, no epilogue,
2717 then one of them follows the note. */
2718 else if (GET_CODE (insn) == JUMP_INSN
2719 && GET_CODE (PATTERN (insn)) == RETURN)
2721 /* A barrier can follow the return insn. */
2722 else if (GET_CODE (insn) == BARRIER)
2724 /* Other kinds of notes can follow also. */
2725 else if (GET_CODE (insn) == NOTE
2726 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2732 insn = PREV_INSN (insn);
2735 /* See if we backed up to the appropriate type of note. */
2736 if (insn != NULL_RTX
2737 && GET_CODE (insn) == NOTE
2738 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END)
2740 if (delete_final_note)
2748 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
2749 jump. Assume that this unconditional jump is to the exit test code. If
2750 the code is sufficiently simple, make a copy of it before INSN,
2751 followed by a jump to the exit of the loop. Then delete the unconditional
2754 Return 1 if we made the change, else 0.
2756 This is only safe immediately after a regscan pass because it uses the
2757 values of regno_first_uid and regno_last_uid. */
2760 duplicate_loop_exit_test (loop_start)
2763 rtx insn, set, reg, p, link;
2764 rtx copy = 0, first_copy = 0;
2766 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
2768 int max_reg = max_reg_num ();
2771 /* Scan the exit code. We do not perform this optimization if any insn:
2775 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
2776 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
2777 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
2780 We also do not do this if we find an insn with ASM_OPERANDS. While
2781 this restriction should not be necessary, copying an insn with
2782 ASM_OPERANDS can confuse asm_noperands in some cases.
2784 Also, don't do this if the exit code is more than 20 insns. */
2786 for (insn = exitcode;
2788 && ! (GET_CODE (insn) == NOTE
2789 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
2790 insn = NEXT_INSN (insn))
2792 switch (GET_CODE (insn))
2798 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
2799 a jump immediately after the loop start that branches outside
2800 the loop but within an outer loop, near the exit test.
2801 If we copied this exit test and created a phony
2802 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
2803 before the exit test look like these could be safely moved
2804 out of the loop even if they actually may be never executed.
2805 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
2807 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
2808 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
2812 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2813 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2814 /* If we were to duplicate this code, we would not move
2815 the BLOCK notes, and so debugging the moved code would
2816 be difficult. Thus, we only move the code with -O2 or
2823 /* The code below would grossly mishandle REG_WAS_0 notes,
2824 so get rid of them here. */
2825 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
2826 remove_note (insn, p);
2827 if (++num_insns > 20
2828 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
2829 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
2837 /* Unless INSN is zero, we can do the optimization. */
2843 /* See if any insn sets a register only used in the loop exit code and
2844 not a user variable. If so, replace it with a new register. */
2845 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2846 if (GET_CODE (insn) == INSN
2847 && (set = single_set (insn)) != 0
2848 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
2849 || (GET_CODE (reg) == SUBREG
2850 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
2851 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
2852 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
2854 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
2855 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
2860 /* We can do the replacement. Allocate reg_map if this is the
2861 first replacement we found. */
2863 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
2865 REG_LOOP_TEST_P (reg) = 1;
2867 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
2871 /* Now copy each insn. */
2872 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2874 switch (GET_CODE (insn))
2877 copy = emit_barrier_before (loop_start);
2880 /* Only copy line-number notes. */
2881 if (NOTE_LINE_NUMBER (insn) >= 0)
2883 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
2884 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
2889 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
2891 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2893 mark_jump_label (PATTERN (copy), copy, 0);
2895 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
2897 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2898 if (REG_NOTE_KIND (link) != REG_LABEL)
2900 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
2903 if (reg_map && REG_NOTES (copy))
2904 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2908 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)), loop_start);
2910 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2911 mark_jump_label (PATTERN (copy), copy, 0);
2912 if (REG_NOTES (insn))
2914 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
2916 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2919 /* If this is a simple jump, add it to the jump chain. */
2921 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
2922 && simplejump_p (copy))
2924 jump_chain[INSN_UID (copy)]
2925 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2926 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2934 /* Record the first insn we copied. We need it so that we can
2935 scan the copied insns for new pseudo registers. */
2940 /* Now clean up by emitting a jump to the end label and deleting the jump
2941 at the start of the loop. */
2942 if (! copy || GET_CODE (copy) != BARRIER)
2944 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
2947 /* Record the first insn we copied. We need it so that we can
2948 scan the copied insns for new pseudo registers. This may not
2949 be strictly necessary since we should have copied at least one
2950 insn above. But I am going to be safe. */
2954 mark_jump_label (PATTERN (copy), copy, 0);
2955 if (INSN_UID (copy) < max_jump_chain
2956 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
2958 jump_chain[INSN_UID (copy)]
2959 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2960 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2962 emit_barrier_before (loop_start);
2965 /* Now scan from the first insn we copied to the last insn we copied
2966 (copy) for new pseudo registers. Do this after the code to jump to
2967 the end label since that might create a new pseudo too. */
2968 reg_scan_update (first_copy, copy, max_reg);
2970 /* Mark the exit code as the virtual top of the converted loop. */
2971 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
2973 delete_insn (next_nonnote_insn (loop_start));
2982 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
2983 loop-end notes between START and END out before START. Assume that
2984 END is not such a note. START may be such a note. Returns the value
2985 of the new starting insn, which may be different if the original start
2989 squeeze_notes (start, end)
2995 for (insn = start; insn != end; insn = next)
2997 next = NEXT_INSN (insn);
2998 if (GET_CODE (insn) == NOTE
2999 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
3000 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
3001 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
3002 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
3003 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
3004 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
3010 rtx prev = PREV_INSN (insn);
3011 PREV_INSN (insn) = PREV_INSN (start);
3012 NEXT_INSN (insn) = start;
3013 NEXT_INSN (PREV_INSN (insn)) = insn;
3014 PREV_INSN (NEXT_INSN (insn)) = insn;
3015 NEXT_INSN (prev) = next;
3016 PREV_INSN (next) = prev;
3024 /* Compare the instructions before insn E1 with those before E2
3025 to find an opportunity for cross jumping.
3026 (This means detecting identical sequences of insns followed by
3027 jumps to the same place, or followed by a label and a jump
3028 to that label, and replacing one with a jump to the other.)
3030 Assume E1 is a jump that jumps to label E2
3031 (that is not always true but it might as well be).
3032 Find the longest possible equivalent sequences
3033 and store the first insns of those sequences into *F1 and *F2.
3034 Store zero there if no equivalent preceding instructions are found.
3036 We give up if we find a label in stream 1.
3037 Actually we could transfer that label into stream 2. */
3040 find_cross_jump (e1, e2, minimum, f1, f2)
3045 register rtx i1 = e1, i2 = e2;
3046 register rtx p1, p2;
3049 rtx last1 = 0, last2 = 0;
3050 rtx afterlast1 = 0, afterlast2 = 0;
3057 i1 = prev_nonnote_insn (i1);
3059 i2 = PREV_INSN (i2);
3060 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
3061 i2 = PREV_INSN (i2);
3066 /* Don't allow the range of insns preceding E1 or E2
3067 to include the other (E2 or E1). */
3068 if (i2 == e1 || i1 == e2)
3071 /* If we will get to this code by jumping, those jumps will be
3072 tensioned to go directly to the new label (before I2),
3073 so this cross-jumping won't cost extra. So reduce the minimum. */
3074 if (GET_CODE (i1) == CODE_LABEL)
3080 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
3083 /* Avoid moving insns across EH regions if either of the insns
3086 && (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
3087 && !in_same_eh_region (i1, i2))
3093 /* If this is a CALL_INSN, compare register usage information.
3094 If we don't check this on stack register machines, the two
3095 CALL_INSNs might be merged leaving reg-stack.c with mismatching
3096 numbers of stack registers in the same basic block.
3097 If we don't check this on machines with delay slots, a delay slot may
3098 be filled that clobbers a parameter expected by the subroutine.
3100 ??? We take the simple route for now and assume that if they're
3101 equal, they were constructed identically. */
3103 if (GET_CODE (i1) == CALL_INSN
3104 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
3105 CALL_INSN_FUNCTION_USAGE (i2)))
3109 /* If cross_jump_death_matters is not 0, the insn's mode
3110 indicates whether or not the insn contains any stack-like
3113 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
3115 /* If register stack conversion has already been done, then
3116 death notes must also be compared before it is certain that
3117 the two instruction streams match. */
3120 HARD_REG_SET i1_regset, i2_regset;
3122 CLEAR_HARD_REG_SET (i1_regset);
3123 CLEAR_HARD_REG_SET (i2_regset);
3125 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
3126 if (REG_NOTE_KIND (note) == REG_DEAD
3127 && STACK_REG_P (XEXP (note, 0)))
3128 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
3130 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
3131 if (REG_NOTE_KIND (note) == REG_DEAD
3132 && STACK_REG_P (XEXP (note, 0)))
3133 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
3135 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
3144 /* Don't allow old-style asm or volatile extended asms to be accepted
3145 for cross jumping purposes. It is conceptually correct to allow
3146 them, since cross-jumping preserves the dynamic instruction order
3147 even though it is changing the static instruction order. However,
3148 if an asm is being used to emit an assembler pseudo-op, such as
3149 the MIPS `.set reorder' pseudo-op, then the static instruction order
3150 matters and it must be preserved. */
3151 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
3152 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
3153 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
3156 if (lose || GET_CODE (p1) != GET_CODE (p2)
3157 || ! rtx_renumbered_equal_p (p1, p2))
3159 /* The following code helps take care of G++ cleanups. */
3163 if (!lose && GET_CODE (p1) == GET_CODE (p2)
3164 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
3165 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
3166 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
3167 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
3168 /* If the equivalences are not to a constant, they may
3169 reference pseudos that no longer exist, so we can't
3171 && CONSTANT_P (XEXP (equiv1, 0))
3172 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
3174 rtx s1 = single_set (i1);
3175 rtx s2 = single_set (i2);
3176 if (s1 != 0 && s2 != 0
3177 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
3179 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
3180 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
3181 if (! rtx_renumbered_equal_p (p1, p2))
3183 else if (apply_change_group ())
3188 /* Insns fail to match; cross jumping is limited to the following
3192 /* Don't allow the insn after a compare to be shared by
3193 cross-jumping unless the compare is also shared.
3194 Here, if either of these non-matching insns is a compare,
3195 exclude the following insn from possible cross-jumping. */
3196 if (sets_cc0_p (p1) || sets_cc0_p (p2))
3197 last1 = afterlast1, last2 = afterlast2, ++minimum;
3200 /* If cross-jumping here will feed a jump-around-jump
3201 optimization, this jump won't cost extra, so reduce
3203 if (GET_CODE (i1) == JUMP_INSN
3205 && prev_real_insn (JUMP_LABEL (i1)) == e1)
3211 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
3213 /* Ok, this insn is potentially includable in a cross-jump here. */
3214 afterlast1 = last1, afterlast2 = last2;
3215 last1 = i1, last2 = i2, --minimum;
3219 if (minimum <= 0 && last1 != 0 && last1 != e1)
3220 *f1 = last1, *f2 = last2;
3224 do_cross_jump (insn, newjpos, newlpos)
3225 rtx insn, newjpos, newlpos;
3227 /* Find an existing label at this point
3228 or make a new one if there is none. */
3229 register rtx label = get_label_before (newlpos);
3231 /* Make the same jump insn jump to the new point. */
3232 if (GET_CODE (PATTERN (insn)) == RETURN)
3234 /* Remove from jump chain of returns. */
3235 delete_from_jump_chain (insn);
3236 /* Change the insn. */
3237 PATTERN (insn) = gen_jump (label);
3238 INSN_CODE (insn) = -1;
3239 JUMP_LABEL (insn) = label;
3240 LABEL_NUSES (label)++;
3241 /* Add to new the jump chain. */
3242 if (INSN_UID (label) < max_jump_chain
3243 && INSN_UID (insn) < max_jump_chain)
3245 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
3246 jump_chain[INSN_UID (label)] = insn;
3250 redirect_jump (insn, label);
3252 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
3253 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
3254 the NEWJPOS stream. */
3256 while (newjpos != insn)
3260 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
3261 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
3262 || REG_NOTE_KIND (lnote) == REG_EQUIV)
3263 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
3264 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
3265 remove_note (newlpos, lnote);
3267 delete_insn (newjpos);
3268 newjpos = next_real_insn (newjpos);
3269 newlpos = next_real_insn (newlpos);
3273 /* Return the label before INSN, or put a new label there. */
3276 get_label_before (insn)
3281 /* Find an existing label at this point
3282 or make a new one if there is none. */
3283 label = prev_nonnote_insn (insn);
3285 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3287 rtx prev = PREV_INSN (insn);
3289 label = gen_label_rtx ();
3290 emit_label_after (label, prev);
3291 LABEL_NUSES (label) = 0;
3296 /* Return the label after INSN, or put a new label there. */
3299 get_label_after (insn)
3304 /* Find an existing label at this point
3305 or make a new one if there is none. */
3306 label = next_nonnote_insn (insn);
3308 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3310 label = gen_label_rtx ();
3311 emit_label_after (label, insn);
3312 LABEL_NUSES (label) = 0;
3317 /* Return 1 if INSN is a jump that jumps to right after TARGET
3318 only on the condition that TARGET itself would drop through.
3319 Assumes that TARGET is a conditional jump. */
3322 jump_back_p (insn, target)
3326 enum rtx_code codei, codet;
3328 if (simplejump_p (insn) || ! condjump_p (insn)
3329 || simplejump_p (target)
3330 || target != prev_real_insn (JUMP_LABEL (insn)))
3333 cinsn = XEXP (SET_SRC (PATTERN (insn)), 0);
3334 ctarget = XEXP (SET_SRC (PATTERN (target)), 0);
3336 codei = GET_CODE (cinsn);
3337 codet = GET_CODE (ctarget);
3339 if (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx)
3341 if (! can_reverse_comparison_p (cinsn, insn))
3343 codei = reverse_condition (codei);
3346 if (XEXP (SET_SRC (PATTERN (target)), 2) == pc_rtx)
3348 if (! can_reverse_comparison_p (ctarget, target))
3350 codet = reverse_condition (codet);
3353 return (codei == codet
3354 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
3355 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
3358 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
3359 return non-zero if it is safe to reverse this comparison. It is if our
3360 floating-point is not IEEE, if this is an NE or EQ comparison, or if
3361 this is known to be an integer comparison. */
3364 can_reverse_comparison_p (comparison, insn)
3370 /* If this is not actually a comparison, we can't reverse it. */
3371 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
3374 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3375 /* If this is an NE comparison, it is safe to reverse it to an EQ
3376 comparison and vice versa, even for floating point. If no operands
3377 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
3378 always false and NE is always true, so the reversal is also valid. */
3380 || GET_CODE (comparison) == NE
3381 || GET_CODE (comparison) == EQ)
3384 arg0 = XEXP (comparison, 0);
3386 /* Make sure ARG0 is one of the actual objects being compared. If we
3387 can't do this, we can't be sure the comparison can be reversed.
3389 Handle cc0 and a MODE_CC register. */
3390 if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
3396 rtx prev = prev_nonnote_insn (insn);
3399 /* First see if the condition code mode alone if enough to say we can
3400 reverse the condition. If not, then search backwards for a set of
3401 ARG0. We do not need to check for an insn clobbering it since valid
3402 code will contain set a set with no intervening clobber. But
3403 stop when we reach a label. */
3404 #ifdef REVERSIBLE_CC_MODE
3405 if (GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC
3406 && REVERSIBLE_CC_MODE (GET_MODE (arg0)))
3410 for (prev = prev_nonnote_insn (insn);
3411 prev != 0 && GET_CODE (prev) != CODE_LABEL;
3412 prev = prev_nonnote_insn (prev))
3413 if ((set = single_set (prev)) != 0
3414 && rtx_equal_p (SET_DEST (set), arg0))
3416 arg0 = SET_SRC (set);
3418 if (GET_CODE (arg0) == COMPARE)
3419 arg0 = XEXP (arg0, 0);
3424 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
3425 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
3426 return (GET_CODE (arg0) == CONST_INT
3427 || (GET_MODE (arg0) != VOIDmode
3428 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
3429 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
3432 /* Given an rtx-code for a comparison, return the code for the negated
3433 comparison. If no such code exists, return UNKNOWN.
3435 WATCH OUT! reverse_condition is not safe to use on a jump that might
3436 be acting on the results of an IEEE floating point comparison, because
3437 of the special treatment of non-signaling nans in comparisons.
3438 Use can_reverse_comparison_p to be sure. */
3441 reverse_condition (code)
3484 /* Similar, but return the code when two operands of a comparison are swapped.
3485 This IS safe for IEEE floating-point. */
3488 swap_condition (code)
3532 /* Given a comparison CODE, return the corresponding unsigned comparison.
3533 If CODE is an equality comparison or already an unsigned comparison,
3534 CODE is returned. */
3537 unsigned_condition (code)
3567 /* Similarly, return the signed version of a comparison. */
3570 signed_condition (code)
3600 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
3601 truth of CODE1 implies the truth of CODE2. */
3604 comparison_dominates_p (code1, code2)
3605 enum rtx_code code1, code2;
3613 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU)
3618 if (code2 == LE || code2 == NE)
3623 if (code2 == GE || code2 == NE)
3628 if (code2 == LEU || code2 == NE)
3633 if (code2 == GEU || code2 == NE)
3644 /* Return 1 if INSN is an unconditional jump and nothing else. */
3650 return (GET_CODE (insn) == JUMP_INSN
3651 && GET_CODE (PATTERN (insn)) == SET
3652 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
3653 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
3656 /* Return nonzero if INSN is a (possibly) conditional jump
3657 and nothing more. */
3663 register rtx x = PATTERN (insn);
3665 if (GET_CODE (x) != SET
3666 || GET_CODE (SET_DEST (x)) != PC)
3670 if (GET_CODE (x) == LABEL_REF)
3672 else return (GET_CODE (x) == IF_THEN_ELSE
3673 && ((GET_CODE (XEXP (x, 2)) == PC
3674 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
3675 || GET_CODE (XEXP (x, 1)) == RETURN))
3676 || (GET_CODE (XEXP (x, 1)) == PC
3677 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
3678 || GET_CODE (XEXP (x, 2)) == RETURN))));
3683 /* Return nonzero if INSN is a (possibly) conditional jump inside a
3687 condjump_in_parallel_p (insn)
3690 register rtx x = PATTERN (insn);
3692 if (GET_CODE (x) != PARALLEL)
3695 x = XVECEXP (x, 0, 0);
3697 if (GET_CODE (x) != SET)
3699 if (GET_CODE (SET_DEST (x)) != PC)
3701 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
3703 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
3705 if (XEXP (SET_SRC (x), 2) == pc_rtx
3706 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
3707 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
3709 if (XEXP (SET_SRC (x), 1) == pc_rtx
3710 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
3711 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
3716 /* Return the label of a conditional jump. */
3719 condjump_label (insn)
3722 register rtx x = PATTERN (insn);
3724 if (GET_CODE (x) == PARALLEL)
3725 x = XVECEXP (x, 0, 0);
3726 if (GET_CODE (x) != SET)
3728 if (GET_CODE (SET_DEST (x)) != PC)
3731 if (GET_CODE (x) == LABEL_REF)
3733 if (GET_CODE (x) != IF_THEN_ELSE)
3735 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
3737 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
3742 /* Return true if INSN is a (possibly conditional) return insn. */
3745 returnjump_p_1 (loc, data)
3747 void *data ATTRIBUTE_UNUSED;
3750 return x && GET_CODE (x) == RETURN;
3757 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
3760 /* Return true if INSN is a jump that only transfers control and
3769 if (GET_CODE (insn) != JUMP_INSN)
3772 set = single_set (insn);
3775 if (GET_CODE (SET_DEST (set)) != PC)
3777 if (side_effects_p (SET_SRC (set)))
3785 /* Return 1 if X is an RTX that does nothing but set the condition codes
3786 and CLOBBER or USE registers.
3787 Return -1 if X does explicitly set the condition codes,
3788 but also does other things. */
3792 rtx x ATTRIBUTE_UNUSED;
3794 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
3796 if (GET_CODE (x) == PARALLEL)
3800 int other_things = 0;
3801 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
3803 if (GET_CODE (XVECEXP (x, 0, i)) == SET
3804 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
3806 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
3809 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
3815 /* Follow any unconditional jump at LABEL;
3816 return the ultimate label reached by any such chain of jumps.
3817 If LABEL is not followed by a jump, return LABEL.
3818 If the chain loops or we can't find end, return LABEL,
3819 since that tells caller to avoid changing the insn.
3821 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
3822 a USE or CLOBBER. */
3825 follow_jumps (label)
3830 register rtx value = label;
3835 && (insn = next_active_insn (value)) != 0
3836 && GET_CODE (insn) == JUMP_INSN
3837 && ((JUMP_LABEL (insn) != 0 && simplejump_p (insn))
3838 || GET_CODE (PATTERN (insn)) == RETURN)
3839 && (next = NEXT_INSN (insn))
3840 && GET_CODE (next) == BARRIER);
3843 /* Don't chain through the insn that jumps into a loop
3844 from outside the loop,
3845 since that would create multiple loop entry jumps
3846 and prevent loop optimization. */
3848 if (!reload_completed)
3849 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
3850 if (GET_CODE (tem) == NOTE
3851 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
3852 /* ??? Optional. Disables some optimizations, but makes
3853 gcov output more accurate with -O. */
3854 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
3857 /* If we have found a cycle, make the insn jump to itself. */
3858 if (JUMP_LABEL (insn) == label)
3861 tem = next_active_insn (JUMP_LABEL (insn));
3862 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
3863 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
3866 value = JUMP_LABEL (insn);
3873 /* Assuming that field IDX of X is a vector of label_refs,
3874 replace each of them by the ultimate label reached by it.
3875 Return nonzero if a change is made.
3876 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
3879 tension_vector_labels (x, idx)
3885 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
3887 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
3888 register rtx nlabel = follow_jumps (olabel);
3889 if (nlabel && nlabel != olabel)
3891 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
3892 ++LABEL_NUSES (nlabel);
3893 if (--LABEL_NUSES (olabel) == 0)
3894 delete_insn (olabel);
3901 /* Find all CODE_LABELs referred to in X, and increment their use counts.
3902 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
3903 in INSN, then store one of them in JUMP_LABEL (INSN).
3904 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
3905 referenced in INSN, add a REG_LABEL note containing that label to INSN.
3906 Also, when there are consecutive labels, canonicalize on the last of them.
3908 Note that two labels separated by a loop-beginning note
3909 must be kept distinct if we have not yet done loop-optimization,
3910 because the gap between them is where loop-optimize
3911 will want to move invariant code to. CROSS_JUMP tells us
3912 that loop-optimization is done with.
3914 Once reload has completed (CROSS_JUMP non-zero), we need not consider
3915 two labels distinct if they are separated by only USE or CLOBBER insns. */
3918 mark_jump_label (x, insn, cross_jump)
3923 register RTX_CODE code = GET_CODE (x);
3925 register const char *fmt;
3941 /* If this is a constant-pool reference, see if it is a label. */
3942 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3943 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3944 mark_jump_label (get_pool_constant (XEXP (x, 0)), insn, cross_jump);
3949 rtx label = XEXP (x, 0);
3954 if (GET_CODE (label) != CODE_LABEL)
3957 /* Ignore references to labels of containing functions. */
3958 if (LABEL_REF_NONLOCAL_P (x))
3961 /* If there are other labels following this one,
3962 replace it with the last of the consecutive labels. */
3963 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
3965 if (GET_CODE (next) == CODE_LABEL)
3967 else if (cross_jump && GET_CODE (next) == INSN
3968 && (GET_CODE (PATTERN (next)) == USE
3969 || GET_CODE (PATTERN (next)) == CLOBBER))
3971 else if (GET_CODE (next) != NOTE)
3973 else if (! cross_jump
3974 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
3975 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
3976 /* ??? Optional. Disables some optimizations, but
3977 makes gcov output more accurate with -O. */
3978 || (flag_test_coverage && NOTE_LINE_NUMBER (next) > 0)))
3982 XEXP (x, 0) = label;
3983 if (! insn || ! INSN_DELETED_P (insn))
3984 ++LABEL_NUSES (label);
3988 if (GET_CODE (insn) == JUMP_INSN)
3989 JUMP_LABEL (insn) = label;
3991 /* If we've changed OLABEL and we had a REG_LABEL note
3992 for it, update it as well. */
3993 else if (label != olabel
3994 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
3995 XEXP (note, 0) = label;
3997 /* Otherwise, add a REG_LABEL note for LABEL unless there already
3999 else if (! find_reg_note (insn, REG_LABEL, label))
4001 /* This code used to ignore labels which refered to dispatch
4002 tables to avoid flow.c generating worse code.
4004 However, in the presense of global optimizations like
4005 gcse which call find_basic_blocks without calling
4006 life_analysis, not recording such labels will lead
4007 to compiler aborts because of inconsistencies in the
4008 flow graph. So we go ahead and record the label.
4010 It may also be the case that the optimization argument
4011 is no longer valid because of the more accurate cfg
4012 we build in find_basic_blocks -- it no longer pessimizes
4013 code when it finds a REG_LABEL note. */
4014 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_LABEL, label,
4021 /* Do walk the labels in a vector, but not the first operand of an
4022 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
4025 if (! INSN_DELETED_P (insn))
4027 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
4029 for (i = 0; i < XVECLEN (x, eltnum); i++)
4030 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX, cross_jump);
4038 fmt = GET_RTX_FORMAT (code);
4039 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4042 mark_jump_label (XEXP (x, i), insn, cross_jump);
4043 else if (fmt[i] == 'E')
4046 for (j = 0; j < XVECLEN (x, i); j++)
4047 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump);
4052 /* If all INSN does is set the pc, delete it,
4053 and delete the insn that set the condition codes for it
4054 if that's what the previous thing was. */
4060 register rtx set = single_set (insn);
4062 if (set && GET_CODE (SET_DEST (set)) == PC)
4063 delete_computation (insn);
4066 /* Verify INSN is a BARRIER and delete it. */
4069 delete_barrier (insn)
4072 if (GET_CODE (insn) != BARRIER)
4078 /* Recursively delete prior insns that compute the value (used only by INSN
4079 which the caller is deleting) stored in the register mentioned by NOTE
4080 which is a REG_DEAD note associated with INSN. */
4083 delete_prior_computation (note, insn)
4088 rtx reg = XEXP (note, 0);
4090 for (our_prev = prev_nonnote_insn (insn);
4091 our_prev && (GET_CODE (our_prev) == INSN
4092 || GET_CODE (our_prev) == CALL_INSN);
4093 our_prev = prev_nonnote_insn (our_prev))
4095 rtx pat = PATTERN (our_prev);
4097 /* If we reach a CALL which is not calling a const function
4098 or the callee pops the arguments, then give up. */
4099 if (GET_CODE (our_prev) == CALL_INSN
4100 && (! CONST_CALL_P (our_prev)
4101 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
4104 /* If we reach a SEQUENCE, it is too complex to try to
4105 do anything with it, so give up. */
4106 if (GET_CODE (pat) == SEQUENCE)
4109 if (GET_CODE (pat) == USE
4110 && GET_CODE (XEXP (pat, 0)) == INSN)
4111 /* reorg creates USEs that look like this. We leave them
4112 alone because reorg needs them for its own purposes. */
4115 if (reg_set_p (reg, pat))
4117 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
4120 if (GET_CODE (pat) == PARALLEL)
4122 /* If we find a SET of something else, we can't
4127 for (i = 0; i < XVECLEN (pat, 0); i++)
4129 rtx part = XVECEXP (pat, 0, i);
4131 if (GET_CODE (part) == SET
4132 && SET_DEST (part) != reg)
4136 if (i == XVECLEN (pat, 0))
4137 delete_computation (our_prev);
4139 else if (GET_CODE (pat) == SET
4140 && GET_CODE (SET_DEST (pat)) == REG)
4142 int dest_regno = REGNO (SET_DEST (pat));
4144 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4145 ? HARD_REGNO_NREGS (dest_regno,
4146 GET_MODE (SET_DEST (pat))) : 1);
4147 int regno = REGNO (reg);
4148 int endregno = regno + (regno < FIRST_PSEUDO_REGISTER
4149 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1);
4151 if (dest_regno >= regno
4152 && dest_endregno <= endregno)
4153 delete_computation (our_prev);
4155 /* We may have a multi-word hard register and some, but not
4156 all, of the words of the register are needed in subsequent
4157 insns. Write REG_UNUSED notes for those parts that were not
4159 else if (dest_regno <= regno
4160 && dest_endregno >= endregno)
4164 REG_NOTES (our_prev)
4165 = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (our_prev));
4167 for (i = dest_regno; i < dest_endregno; i++)
4168 if (! find_regno_note (our_prev, REG_UNUSED, i))
4171 if (i == dest_endregno)
4172 delete_computation (our_prev);
4179 /* If PAT references the register that dies here, it is an
4180 additional use. Hence any prior SET isn't dead. However, this
4181 insn becomes the new place for the REG_DEAD note. */
4182 if (reg_overlap_mentioned_p (reg, pat))
4184 XEXP (note, 1) = REG_NOTES (our_prev);
4185 REG_NOTES (our_prev) = note;
4191 /* Delete INSN and recursively delete insns that compute values used only
4192 by INSN. This uses the REG_DEAD notes computed during flow analysis.
4193 If we are running before flow.c, we need do nothing since flow.c will
4194 delete dead code. We also can't know if the registers being used are
4195 dead or not at this point.
4197 Otherwise, look at all our REG_DEAD notes. If a previous insn does
4198 nothing other than set a register that dies in this insn, we can delete
4201 On machines with CC0, if CC0 is used in this insn, we may be able to
4202 delete the insn that set it. */
4205 delete_computation (insn)
4212 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
4214 rtx prev = prev_nonnote_insn (insn);
4215 /* We assume that at this stage
4216 CC's are always set explicitly
4217 and always immediately before the jump that
4218 will use them. So if the previous insn
4219 exists to set the CC's, delete it
4220 (unless it performs auto-increments, etc.). */
4221 if (prev && GET_CODE (prev) == INSN
4222 && sets_cc0_p (PATTERN (prev)))
4224 if (sets_cc0_p (PATTERN (prev)) > 0
4225 && ! side_effects_p (PATTERN (prev)))
4226 delete_computation (prev);
4228 /* Otherwise, show that cc0 won't be used. */
4229 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
4230 cc0_rtx, REG_NOTES (prev));
4235 #ifdef INSN_SCHEDULING
4236 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
4237 reload has completed. The schedulers need to be fixed. Until
4238 they are, we must not rely on the death notes here. */
4239 if (reload_completed && flag_schedule_insns_after_reload)
4246 /* The REG_DEAD note may have been omitted for a register
4247 which is both set and used by the insn. */
4248 set = single_set (insn);
4249 if (set && GET_CODE (SET_DEST (set)) == REG)
4251 int dest_regno = REGNO (SET_DEST (set));
4253 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4254 ? HARD_REGNO_NREGS (dest_regno,
4255 GET_MODE (SET_DEST (set))) : 1);
4258 for (i = dest_regno; i < dest_endregno; i++)
4260 if (! refers_to_regno_p (i, i + 1, SET_SRC (set), NULL_PTR)
4261 || find_regno_note (insn, REG_DEAD, i))
4264 note = gen_rtx_EXPR_LIST (REG_DEAD, (i < FIRST_PSEUDO_REGISTER
4265 ? gen_rtx_REG (reg_raw_mode[i], i)
4266 : SET_DEST (set)), NULL_RTX);
4267 delete_prior_computation (note, insn);
4271 for (note = REG_NOTES (insn); note; note = next)
4273 next = XEXP (note, 1);
4275 if (REG_NOTE_KIND (note) != REG_DEAD
4276 /* Verify that the REG_NOTE is legitimate. */
4277 || GET_CODE (XEXP (note, 0)) != REG)
4280 delete_prior_computation (note, insn);
4286 /* Delete insn INSN from the chain of insns and update label ref counts.
4287 May delete some following insns as a consequence; may even delete
4288 a label elsewhere and insns that follow it.
4290 Returns the first insn after INSN that was not deleted. */
4296 register rtx next = NEXT_INSN (insn);
4297 register rtx prev = PREV_INSN (insn);
4298 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
4299 register int dont_really_delete = 0;
4301 while (next && INSN_DELETED_P (next))
4302 next = NEXT_INSN (next);
4304 /* This insn is already deleted => return first following nondeleted. */
4305 if (INSN_DELETED_P (insn))
4309 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
4311 /* Don't delete user-declared labels. Convert them to special NOTEs
4313 if (was_code_label && LABEL_NAME (insn) != 0 && ! dont_really_delete)
4315 PUT_CODE (insn, NOTE);
4316 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
4317 NOTE_SOURCE_FILE (insn) = 0;
4318 dont_really_delete = 1;
4321 /* Mark this insn as deleted. */
4322 INSN_DELETED_P (insn) = 1;
4324 /* If this is an unconditional jump, delete it from the jump chain. */
4325 if (simplejump_p (insn))
4326 delete_from_jump_chain (insn);
4328 /* If instruction is followed by a barrier,
4329 delete the barrier too. */
4331 if (next != 0 && GET_CODE (next) == BARRIER)
4333 INSN_DELETED_P (next) = 1;
4334 next = NEXT_INSN (next);
4337 /* Patch out INSN (and the barrier if any) */
4339 if (! dont_really_delete)
4343 NEXT_INSN (prev) = next;
4344 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
4345 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
4346 XVECLEN (PATTERN (prev), 0) - 1)) = next;
4351 PREV_INSN (next) = prev;
4352 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
4353 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
4356 if (prev && NEXT_INSN (prev) == 0)
4357 set_last_insn (prev);
4360 /* If deleting a jump, decrement the count of the label,
4361 and delete the label if it is now unused. */
4363 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
4365 rtx lab = JUMP_LABEL (insn), lab_next;
4367 if (--LABEL_NUSES (lab) == 0)
4369 /* This can delete NEXT or PREV,
4370 either directly if NEXT is JUMP_LABEL (INSN),
4371 or indirectly through more levels of jumps. */
4374 /* I feel a little doubtful about this loop,
4375 but I see no clean and sure alternative way
4376 to find the first insn after INSN that is not now deleted.
4377 I hope this works. */
4378 while (next && INSN_DELETED_P (next))
4379 next = NEXT_INSN (next);
4382 else if ((lab_next = next_nonnote_insn (lab)) != NULL
4383 && GET_CODE (lab_next) == JUMP_INSN
4384 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
4385 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
4387 /* If we're deleting the tablejump, delete the dispatch table.
4388 We may not be able to kill the label immediately preceeding
4389 just yet, as it might be referenced in code leading up to
4391 delete_insn (lab_next);
4395 /* Likewise if we're deleting a dispatch table. */
4397 if (GET_CODE (insn) == JUMP_INSN
4398 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
4399 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
4401 rtx pat = PATTERN (insn);
4402 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
4403 int len = XVECLEN (pat, diff_vec_p);
4405 for (i = 0; i < len; i++)
4406 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
4407 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
4408 while (next && INSN_DELETED_P (next))
4409 next = NEXT_INSN (next);
4413 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
4414 prev = PREV_INSN (prev);
4416 /* If INSN was a label and a dispatch table follows it,
4417 delete the dispatch table. The tablejump must have gone already.
4418 It isn't useful to fall through into a table. */
4421 && NEXT_INSN (insn) != 0
4422 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
4423 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
4424 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
4425 next = delete_insn (NEXT_INSN (insn));
4427 /* If INSN was a label, delete insns following it if now unreachable. */
4429 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
4431 register RTX_CODE code;
4433 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
4434 || code == NOTE || code == BARRIER
4435 || (code == CODE_LABEL && INSN_DELETED_P (next))))
4438 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
4439 next = NEXT_INSN (next);
4440 /* Keep going past other deleted labels to delete what follows. */
4441 else if (code == CODE_LABEL && INSN_DELETED_P (next))
4442 next = NEXT_INSN (next);
4444 /* Note: if this deletes a jump, it can cause more
4445 deletion of unreachable code, after a different label.
4446 As long as the value from this recursive call is correct,
4447 this invocation functions correctly. */
4448 next = delete_insn (next);
4455 /* Advance from INSN till reaching something not deleted
4456 then return that. May return INSN itself. */
4459 next_nondeleted_insn (insn)
4462 while (INSN_DELETED_P (insn))
4463 insn = NEXT_INSN (insn);
4467 /* Delete a range of insns from FROM to TO, inclusive.
4468 This is for the sake of peephole optimization, so assume
4469 that whatever these insns do will still be done by a new
4470 peephole insn that will replace them. */
4473 delete_for_peephole (from, to)
4474 register rtx from, to;
4476 register rtx insn = from;
4480 register rtx next = NEXT_INSN (insn);
4481 register rtx prev = PREV_INSN (insn);
4483 if (GET_CODE (insn) != NOTE)
4485 INSN_DELETED_P (insn) = 1;
4487 /* Patch this insn out of the chain. */
4488 /* We don't do this all at once, because we
4489 must preserve all NOTEs. */
4491 NEXT_INSN (prev) = next;
4494 PREV_INSN (next) = prev;
4502 /* Note that if TO is an unconditional jump
4503 we *do not* delete the BARRIER that follows,
4504 since the peephole that replaces this sequence
4505 is also an unconditional jump in that case. */
4508 /* We have determined that INSN is never reached, and are about to
4509 delete it. Print a warning if the user asked for one.
4511 To try to make this warning more useful, this should only be called
4512 once per basic block not reached, and it only warns when the basic
4513 block contains more than one line from the current function, and
4514 contains at least one operation. CSE and inlining can duplicate insns,
4515 so it's possible to get spurious warnings from this. */
4518 never_reached_warning (avoided_insn)
4522 rtx a_line_note = NULL;
4523 int two_avoided_lines = 0;
4524 int contains_insn = 0;
4526 if (! warn_notreached)
4529 /* Scan forwards, looking at LINE_NUMBER notes, until
4530 we hit a LABEL or we run out of insns. */
4532 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
4534 if (GET_CODE (insn) == CODE_LABEL)
4536 else if (GET_CODE (insn) == NOTE /* A line number note? */
4537 && NOTE_LINE_NUMBER (insn) >= 0)
4539 if (a_line_note == NULL)
4542 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
4543 != NOTE_LINE_NUMBER (insn));
4545 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
4548 if (two_avoided_lines && contains_insn)
4549 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
4550 NOTE_LINE_NUMBER (a_line_note),
4551 "will never be executed");
4554 /* Invert the condition of the jump JUMP, and make it jump
4555 to label NLABEL instead of where it jumps now. */
4558 invert_jump (jump, nlabel)
4561 /* We have to either invert the condition and change the label or
4562 do neither. Either operation could fail. We first try to invert
4563 the jump. If that succeeds, we try changing the label. If that fails,
4564 we invert the jump back to what it was. */
4566 if (! invert_exp (PATTERN (jump), jump))
4569 if (redirect_jump (jump, nlabel))
4571 if (flag_branch_probabilities)
4573 rtx note = find_reg_note (jump, REG_BR_PROB, 0);
4575 /* An inverted jump means that a probability taken becomes a
4576 probability not taken. Subtract the branch probability from the
4577 probability base to convert it back to a taken probability.
4578 (We don't flip the probability on a branch that's never taken. */
4579 if (note && XINT (XEXP (note, 0), 0) >= 0)
4580 XINT (XEXP (note, 0), 0) = REG_BR_PROB_BASE - XINT (XEXP (note, 0), 0);
4586 if (! invert_exp (PATTERN (jump), jump))
4587 /* This should just be putting it back the way it was. */
4593 /* Invert the jump condition of rtx X contained in jump insn, INSN.
4595 Return 1 if we can do so, 0 if we cannot find a way to do so that
4596 matches a pattern. */
4599 invert_exp (x, insn)
4603 register RTX_CODE code;
4605 register const char *fmt;
4607 code = GET_CODE (x);
4609 if (code == IF_THEN_ELSE)
4611 register rtx comp = XEXP (x, 0);
4614 /* We can do this in two ways: The preferable way, which can only
4615 be done if this is not an integer comparison, is to reverse
4616 the comparison code. Otherwise, swap the THEN-part and ELSE-part
4617 of the IF_THEN_ELSE. If we can't do either, fail. */
4619 if (can_reverse_comparison_p (comp, insn)
4620 && validate_change (insn, &XEXP (x, 0),
4621 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
4622 GET_MODE (comp), XEXP (comp, 0),
4623 XEXP (comp, 1)), 0))
4627 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
4628 validate_change (insn, &XEXP (x, 2), tem, 1);
4629 return apply_change_group ();
4632 fmt = GET_RTX_FORMAT (code);
4633 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4637 if (! invert_exp (XEXP (x, i), insn))
4640 else if (fmt[i] == 'E')
4643 for (j = 0; j < XVECLEN (x, i); j++)
4644 if (!invert_exp (XVECEXP (x, i, j), insn))
4652 /* Make jump JUMP jump to label NLABEL instead of where it jumps now.
4653 If the old jump target label is unused as a result,
4654 it and the code following it may be deleted.
4656 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
4659 The return value will be 1 if the change was made, 0 if it wasn't (this
4660 can only occur for NLABEL == 0). */
4663 redirect_jump (jump, nlabel)
4666 register rtx olabel = JUMP_LABEL (jump);
4668 if (nlabel == olabel)
4671 if (! redirect_exp (&PATTERN (jump), olabel, nlabel, jump))
4674 /* If this is an unconditional branch, delete it from the jump_chain of
4675 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
4676 have UID's in range and JUMP_CHAIN is valid). */
4677 if (jump_chain && (simplejump_p (jump)
4678 || GET_CODE (PATTERN (jump)) == RETURN))
4680 int label_index = nlabel ? INSN_UID (nlabel) : 0;
4682 delete_from_jump_chain (jump);
4683 if (label_index < max_jump_chain
4684 && INSN_UID (jump) < max_jump_chain)
4686 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
4687 jump_chain[label_index] = jump;
4691 JUMP_LABEL (jump) = nlabel;
4693 ++LABEL_NUSES (nlabel);
4695 if (olabel && --LABEL_NUSES (olabel) == 0)
4696 delete_insn (olabel);
4701 /* Delete the instruction JUMP from any jump chain it might be on. */
4704 delete_from_jump_chain (jump)
4708 rtx olabel = JUMP_LABEL (jump);
4710 /* Handle unconditional jumps. */
4711 if (jump_chain && olabel != 0
4712 && INSN_UID (olabel) < max_jump_chain
4713 && simplejump_p (jump))
4714 index = INSN_UID (olabel);
4715 /* Handle return insns. */
4716 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
4720 if (jump_chain[index] == jump)
4721 jump_chain[index] = jump_chain[INSN_UID (jump)];
4726 for (insn = jump_chain[index];
4728 insn = jump_chain[INSN_UID (insn)])
4729 if (jump_chain[INSN_UID (insn)] == jump)
4731 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
4737 /* If NLABEL is nonzero, throughout the rtx at LOC,
4738 alter (LABEL_REF OLABEL) to (LABEL_REF NLABEL). If OLABEL is
4739 zero, alter (RETURN) to (LABEL_REF NLABEL).
4741 If NLABEL is zero, alter (LABEL_REF OLABEL) to (RETURN) and check
4742 validity with validate_change. Convert (set (pc) (label_ref olabel))
4745 Return 0 if we found a change we would like to make but it is invalid.
4746 Otherwise, return 1. */
4749 redirect_exp (loc, olabel, nlabel, insn)
4754 register rtx x = *loc;
4755 register RTX_CODE code = GET_CODE (x);
4757 register const char *fmt;
4759 if (code == LABEL_REF)
4761 if (XEXP (x, 0) == olabel)
4764 XEXP (x, 0) = nlabel;
4766 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4770 else if (code == RETURN && olabel == 0)
4772 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
4773 if (loc == &PATTERN (insn))
4774 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
4775 return validate_change (insn, loc, x, 0);
4778 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
4779 && GET_CODE (SET_SRC (x)) == LABEL_REF
4780 && XEXP (SET_SRC (x), 0) == olabel)
4781 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4783 fmt = GET_RTX_FORMAT (code);
4784 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4788 if (! redirect_exp (&XEXP (x, i), olabel, nlabel, insn))
4791 else if (fmt[i] == 'E')
4794 for (j = 0; j < XVECLEN (x, i); j++)
4795 if (! redirect_exp (&XVECEXP (x, i, j), olabel, nlabel, insn))
4803 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
4805 If the old jump target label (before the dispatch table) becomes unused,
4806 it and the dispatch table may be deleted. In that case, find the insn
4807 before the jump references that label and delete it and logical successors
4811 redirect_tablejump (jump, nlabel)
4814 register rtx olabel = JUMP_LABEL (jump);
4816 /* Add this jump to the jump_chain of NLABEL. */
4817 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
4818 && INSN_UID (jump) < max_jump_chain)
4820 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
4821 jump_chain[INSN_UID (nlabel)] = jump;
4824 PATTERN (jump) = gen_jump (nlabel);
4825 JUMP_LABEL (jump) = nlabel;
4826 ++LABEL_NUSES (nlabel);
4827 INSN_CODE (jump) = -1;
4829 if (--LABEL_NUSES (olabel) == 0)
4831 delete_labelref_insn (jump, olabel, 0);
4832 delete_insn (olabel);
4836 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
4837 If we found one, delete it and then delete this insn if DELETE_THIS is
4838 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
4841 delete_labelref_insn (insn, label, delete_this)
4848 if (GET_CODE (insn) != NOTE
4849 && reg_mentioned_p (label, PATTERN (insn)))
4860 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
4861 if (delete_labelref_insn (XEXP (link, 0), label, 1))
4875 /* Like rtx_equal_p except that it considers two REGs as equal
4876 if they renumber to the same value and considers two commutative
4877 operations to be the same if the order of the operands has been
4880 ??? Addition is not commutative on the PA due to the weird implicit
4881 space register selection rules for memory addresses. Therefore, we
4882 don't consider a + b == b + a.
4884 We could/should make this test a little tighter. Possibly only
4885 disabling it on the PA via some backend macro or only disabling this
4886 case when the PLUS is inside a MEM. */
4889 rtx_renumbered_equal_p (x, y)
4893 register RTX_CODE code = GET_CODE (x);
4894 register const char *fmt;
4899 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
4900 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
4901 && GET_CODE (SUBREG_REG (y)) == REG)))
4903 int reg_x = -1, reg_y = -1;
4904 int word_x = 0, word_y = 0;
4906 if (GET_MODE (x) != GET_MODE (y))
4909 /* If we haven't done any renumbering, don't
4910 make any assumptions. */
4911 if (reg_renumber == 0)
4912 return rtx_equal_p (x, y);
4916 reg_x = REGNO (SUBREG_REG (x));
4917 word_x = SUBREG_WORD (x);
4919 if (reg_renumber[reg_x] >= 0)
4921 reg_x = reg_renumber[reg_x] + word_x;
4929 if (reg_renumber[reg_x] >= 0)
4930 reg_x = reg_renumber[reg_x];
4933 if (GET_CODE (y) == SUBREG)
4935 reg_y = REGNO (SUBREG_REG (y));
4936 word_y = SUBREG_WORD (y);
4938 if (reg_renumber[reg_y] >= 0)
4940 reg_y = reg_renumber[reg_y];
4948 if (reg_renumber[reg_y] >= 0)
4949 reg_y = reg_renumber[reg_y];
4952 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
4955 /* Now we have disposed of all the cases
4956 in which different rtx codes can match. */
4957 if (code != GET_CODE (y))
4969 return INTVAL (x) == INTVAL (y);
4972 /* We can't assume nonlocal labels have their following insns yet. */
4973 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
4974 return XEXP (x, 0) == XEXP (y, 0);
4976 /* Two label-refs are equivalent if they point at labels
4977 in the same position in the instruction stream. */
4978 return (next_real_insn (XEXP (x, 0))
4979 == next_real_insn (XEXP (y, 0)));
4982 return XSTR (x, 0) == XSTR (y, 0);
4985 /* If we didn't match EQ equality above, they aren't the same. */
4992 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
4994 if (GET_MODE (x) != GET_MODE (y))
4997 /* For commutative operations, the RTX match if the operand match in any
4998 order. Also handle the simple binary and unary cases without a loop.
5000 ??? Don't consider PLUS a commutative operator; see comments above. */
5001 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5003 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
5004 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
5005 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
5006 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
5007 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
5008 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
5009 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
5010 else if (GET_RTX_CLASS (code) == '1')
5011 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
5013 /* Compare the elements. If any pair of corresponding elements
5014 fail to match, return 0 for the whole things. */
5016 fmt = GET_RTX_FORMAT (code);
5017 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5023 if (XWINT (x, i) != XWINT (y, i))
5028 if (XINT (x, i) != XINT (y, i))
5033 if (strcmp (XSTR (x, i), XSTR (y, i)))
5038 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
5043 if (XEXP (x, i) != XEXP (y, i))
5050 if (XVECLEN (x, i) != XVECLEN (y, i))
5052 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
5053 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
5064 /* If X is a hard register or equivalent to one or a subregister of one,
5065 return the hard register number. If X is a pseudo register that was not
5066 assigned a hard register, return the pseudo register number. Otherwise,
5067 return -1. Any rtx is valid for X. */
5073 if (GET_CODE (x) == REG)
5075 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
5076 return reg_renumber[REGNO (x)];
5079 if (GET_CODE (x) == SUBREG)
5081 int base = true_regnum (SUBREG_REG (x));
5082 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
5083 return SUBREG_WORD (x) + base;
5088 /* Optimize code of the form:
5090 for (x = a[i]; x; ...)
5092 for (x = a[i]; x; ...)
5096 Loop optimize will change the above code into
5100 { ...; if (! (x = ...)) break; }
5103 { ...; if (! (x = ...)) break; }
5106 In general, if the first test fails, the program can branch
5107 directly to `foo' and skip the second try which is doomed to fail.
5108 We run this after loop optimization and before flow analysis. */
5110 /* When comparing the insn patterns, we track the fact that different
5111 pseudo-register numbers may have been used in each computation.
5112 The following array stores an equivalence -- same_regs[I] == J means
5113 that pseudo register I was used in the first set of tests in a context
5114 where J was used in the second set. We also count the number of such
5115 pending equivalences. If nonzero, the expressions really aren't the
5118 static int *same_regs;
5120 static int num_same_regs;
5122 /* Track any registers modified between the target of the first jump and
5123 the second jump. They never compare equal. */
5125 static char *modified_regs;
5127 /* Record if memory was modified. */
5129 static int modified_mem;
5131 /* Called via note_stores on each insn between the target of the first
5132 branch and the second branch. It marks any changed registers. */
5135 mark_modified_reg (dest, x, data)
5137 rtx x ATTRIBUTE_UNUSED;
5138 void *data ATTRIBUTE_UNUSED;
5142 if (GET_CODE (dest) == SUBREG)
5143 dest = SUBREG_REG (dest);
5145 if (GET_CODE (dest) == MEM)
5148 if (GET_CODE (dest) != REG)
5151 regno = REGNO (dest);
5152 if (regno >= FIRST_PSEUDO_REGISTER)
5153 modified_regs[regno] = 1;
5155 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
5156 modified_regs[regno + i] = 1;
5159 /* F is the first insn in the chain of insns. */
5162 thread_jumps (f, max_reg, flag_before_loop)
5165 int flag_before_loop;
5167 /* Basic algorithm is to find a conditional branch,
5168 the label it may branch to, and the branch after
5169 that label. If the two branches test the same condition,
5170 walk back from both branch paths until the insn patterns
5171 differ, or code labels are hit. If we make it back to
5172 the target of the first branch, then we know that the first branch
5173 will either always succeed or always fail depending on the relative
5174 senses of the two branches. So adjust the first branch accordingly
5177 rtx label, b1, b2, t1, t2;
5178 enum rtx_code code1, code2;
5179 rtx b1op0, b1op1, b2op0, b2op1;
5184 /* Allocate register tables and quick-reset table. */
5185 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
5186 same_regs = (int *) xmalloc (max_reg * sizeof (int));
5187 all_reset = (int *) xmalloc (max_reg * sizeof (int));
5188 for (i = 0; i < max_reg; i++)
5195 for (b1 = f; b1; b1 = NEXT_INSN (b1))
5197 /* Get to a candidate branch insn. */
5198 if (GET_CODE (b1) != JUMP_INSN
5199 || ! condjump_p (b1) || simplejump_p (b1)
5200 || JUMP_LABEL (b1) == 0)
5203 bzero (modified_regs, max_reg * sizeof (char));
5206 bcopy ((char *) all_reset, (char *) same_regs,
5207 max_reg * sizeof (int));
5210 label = JUMP_LABEL (b1);
5212 /* Look for a branch after the target. Record any registers and
5213 memory modified between the target and the branch. Stop when we
5214 get to a label since we can't know what was changed there. */
5215 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
5217 if (GET_CODE (b2) == CODE_LABEL)
5220 else if (GET_CODE (b2) == JUMP_INSN)
5222 /* If this is an unconditional jump and is the only use of
5223 its target label, we can follow it. */
5224 if (simplejump_p (b2)
5225 && JUMP_LABEL (b2) != 0
5226 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
5228 b2 = JUMP_LABEL (b2);
5235 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
5238 if (GET_CODE (b2) == CALL_INSN)
5241 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
5242 if (call_used_regs[i] && ! fixed_regs[i]
5243 && i != STACK_POINTER_REGNUM
5244 && i != FRAME_POINTER_REGNUM
5245 && i != HARD_FRAME_POINTER_REGNUM
5246 && i != ARG_POINTER_REGNUM)
5247 modified_regs[i] = 1;
5250 note_stores (PATTERN (b2), mark_modified_reg, NULL);
5253 /* Check the next candidate branch insn from the label
5256 || GET_CODE (b2) != JUMP_INSN
5258 || ! condjump_p (b2)
5259 || simplejump_p (b2))
5262 /* Get the comparison codes and operands, reversing the
5263 codes if appropriate. If we don't have comparison codes,
5264 we can't do anything. */
5265 b1op0 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 0);
5266 b1op1 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 1);
5267 code1 = GET_CODE (XEXP (SET_SRC (PATTERN (b1)), 0));
5268 if (XEXP (SET_SRC (PATTERN (b1)), 1) == pc_rtx)
5269 code1 = reverse_condition (code1);
5271 b2op0 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 0);
5272 b2op1 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 1);
5273 code2 = GET_CODE (XEXP (SET_SRC (PATTERN (b2)), 0));
5274 if (XEXP (SET_SRC (PATTERN (b2)), 1) == pc_rtx)
5275 code2 = reverse_condition (code2);
5277 /* If they test the same things and knowing that B1 branches
5278 tells us whether or not B2 branches, check if we
5279 can thread the branch. */
5280 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
5281 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
5282 && (comparison_dominates_p (code1, code2)
5283 || (can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1)),
5286 && comparison_dominates_p (code1, reverse_condition (code2)))))
5289 t1 = prev_nonnote_insn (b1);
5290 t2 = prev_nonnote_insn (b2);
5292 while (t1 != 0 && t2 != 0)
5296 /* We have reached the target of the first branch.
5297 If there are no pending register equivalents,
5298 we know that this branch will either always
5299 succeed (if the senses of the two branches are
5300 the same) or always fail (if not). */
5303 if (num_same_regs != 0)
5306 if (comparison_dominates_p (code1, code2))
5307 new_label = JUMP_LABEL (b2);
5309 new_label = get_label_after (b2);
5311 if (JUMP_LABEL (b1) != new_label)
5313 rtx prev = PREV_INSN (new_label);
5315 if (flag_before_loop
5316 && GET_CODE (prev) == NOTE
5317 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
5319 /* Don't thread to the loop label. If a loop
5320 label is reused, loop optimization will
5321 be disabled for that loop. */
5322 new_label = gen_label_rtx ();
5323 emit_label_after (new_label, PREV_INSN (prev));
5325 changed |= redirect_jump (b1, new_label);
5330 /* If either of these is not a normal insn (it might be
5331 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
5332 have already been skipped above.) Similarly, fail
5333 if the insns are different. */
5334 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
5335 || recog_memoized (t1) != recog_memoized (t2)
5336 || ! rtx_equal_for_thread_p (PATTERN (t1),
5340 t1 = prev_nonnote_insn (t1);
5341 t2 = prev_nonnote_insn (t2);
5348 free (modified_regs);
5353 /* This is like RTX_EQUAL_P except that it knows about our handling of
5354 possibly equivalent registers and knows to consider volatile and
5355 modified objects as not equal.
5357 YINSN is the insn containing Y. */
5360 rtx_equal_for_thread_p (x, y, yinsn)
5366 register enum rtx_code code;
5367 register const char *fmt;
5369 code = GET_CODE (x);
5370 /* Rtx's of different codes cannot be equal. */
5371 if (code != GET_CODE (y))
5374 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
5375 (REG:SI x) and (REG:HI x) are NOT equivalent. */
5377 if (GET_MODE (x) != GET_MODE (y))
5380 /* For floating-point, consider everything unequal. This is a bit
5381 pessimistic, but this pass would only rarely do anything for FP
5383 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
5384 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
5387 /* For commutative operations, the RTX match if the operand match in any
5388 order. Also handle the simple binary and unary cases without a loop. */
5389 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5390 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5391 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
5392 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
5393 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
5394 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
5395 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5396 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
5397 else if (GET_RTX_CLASS (code) == '1')
5398 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5400 /* Handle special-cases first. */
5404 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
5407 /* If neither is user variable or hard register, check for possible
5409 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
5410 || REGNO (x) < FIRST_PSEUDO_REGISTER
5411 || REGNO (y) < FIRST_PSEUDO_REGISTER)
5414 if (same_regs[REGNO (x)] == -1)
5416 same_regs[REGNO (x)] = REGNO (y);
5419 /* If this is the first time we are seeing a register on the `Y'
5420 side, see if it is the last use. If not, we can't thread the
5421 jump, so mark it as not equivalent. */
5422 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
5428 return (same_regs[REGNO (x)] == REGNO (y));
5433 /* If memory modified or either volatile, not equivalent.
5434 Else, check address. */
5435 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5438 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5441 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5447 /* Cancel a pending `same_regs' if setting equivalenced registers.
5448 Then process source. */
5449 if (GET_CODE (SET_DEST (x)) == REG
5450 && GET_CODE (SET_DEST (y)) == REG)
5452 if (same_regs[REGNO (SET_DEST (x))] == REGNO (SET_DEST (y)))
5454 same_regs[REGNO (SET_DEST (x))] = -1;
5457 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
5461 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
5464 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
5467 return XEXP (x, 0) == XEXP (y, 0);
5470 return XSTR (x, 0) == XSTR (y, 0);
5479 fmt = GET_RTX_FORMAT (code);
5480 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5485 if (XWINT (x, i) != XWINT (y, i))
5491 if (XINT (x, i) != XINT (y, i))
5497 /* Two vectors must have the same length. */
5498 if (XVECLEN (x, i) != XVECLEN (y, i))
5501 /* And the corresponding elements must match. */
5502 for (j = 0; j < XVECLEN (x, i); j++)
5503 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
5504 XVECEXP (y, i, j), yinsn) == 0)
5509 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
5515 if (strcmp (XSTR (x, i), XSTR (y, i)))
5520 /* These are just backpointers, so they don't matter. */
5527 /* It is believed that rtx's at this level will never
5528 contain anything but integers and other rtx's,
5529 except for within LABEL_REFs and SYMBOL_REFs. */
5538 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
5539 /* Return the insn that NEW can be safely inserted in front of starting at
5540 the jump insn INSN. Return 0 if it is not safe to do this jump
5541 optimization. Note that NEW must contain a single set. */
5544 find_insert_position (insn, new)
5551 /* If NEW does not clobber, it is safe to insert NEW before INSN. */
5552 if (GET_CODE (PATTERN (new)) != PARALLEL)
5555 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5556 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5557 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5564 /* There is a good chance that the previous insn PREV sets the thing
5565 being clobbered (often the CC in a hard reg). If PREV does not
5566 use what NEW sets, we can insert NEW before PREV. */
5568 prev = prev_active_insn (insn);
5569 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5570 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5571 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5573 && ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5577 return reg_mentioned_p (SET_DEST (single_set (new)), prev) ? 0 : prev;
5579 #endif /* !HAVE_cc0 */
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