1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 1998, 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 /* This is the jump-optimization pass of the compiler.
24 It is run two or three times: once before cse, sometimes once after cse,
25 and once after reload (before final).
27 jump_optimize deletes unreachable code and labels that are not used.
28 It also deletes jumps that jump to the following insn,
29 and simplifies jumps around unconditional jumps and jumps
30 to unconditional jumps.
32 Each CODE_LABEL has a count of the times it is used
33 stored in the LABEL_NUSES internal field, and each JUMP_INSN
34 has one label that it refers to stored in the
35 JUMP_LABEL internal field. With this we can detect labels that
36 become unused because of the deletion of all the jumps that
37 formerly used them. The JUMP_LABEL info is sometimes looked
40 Optionally, cross-jumping can be done. Currently it is done
41 only the last time (when after reload and before final).
42 In fact, the code for cross-jumping now assumes that register
43 allocation has been done, since it uses `rtx_renumbered_equal_p'.
45 Jump optimization is done after cse when cse's constant-propagation
46 causes jumps to become unconditional or to be deleted.
48 Unreachable loops are not detected here, because the labels
49 have references and the insns appear reachable from the labels.
50 find_basic_blocks in flow.c finds and deletes such loops.
52 The subroutines delete_insn, redirect_jump, and invert_jump are used
53 from other passes as well. */
60 #include "hard-reg-set.h"
62 #include "insn-config.h"
63 #include "insn-flags.h"
64 #include "insn-attr.h"
72 /* ??? Eventually must record somehow the labels used by jumps
73 from nested functions. */
74 /* Pre-record the next or previous real insn for each label?
75 No, this pass is very fast anyway. */
76 /* Condense consecutive labels?
77 This would make life analysis faster, maybe. */
78 /* Optimize jump y; x: ... y: jumpif... x?
79 Don't know if it is worth bothering with. */
80 /* Optimize two cases of conditional jump to conditional jump?
81 This can never delete any instruction or make anything dead,
82 or even change what is live at any point.
83 So perhaps let combiner do it. */
85 /* Vector indexed by uid.
86 For each CODE_LABEL, index by its uid to get first unconditional jump
87 that jumps to the label.
88 For each JUMP_INSN, index by its uid to get the next unconditional jump
89 that jumps to the same label.
90 Element 0 is the start of a chain of all return insns.
91 (It is safe to use element 0 because insn uid 0 is not used. */
93 static rtx *jump_chain;
95 /* Maximum index in jump_chain. */
97 static int max_jump_chain;
99 /* Set nonzero by jump_optimize if control can fall through
100 to the end of the function. */
103 /* Indicates whether death notes are significant in cross jump analysis.
104 Normally they are not significant, because of A and B jump to C,
105 and R dies in A, it must die in B. But this might not be true after
106 stack register conversion, and we must compare death notes in that
109 static int cross_jump_death_matters = 0;
111 static int init_label_info PARAMS ((rtx));
112 static void delete_barrier_successors PARAMS ((rtx));
113 static void mark_all_labels PARAMS ((rtx, int));
114 static rtx delete_unreferenced_labels PARAMS ((rtx));
115 static void delete_noop_moves PARAMS ((rtx));
116 static int calculate_can_reach_end PARAMS ((rtx, int));
117 static int duplicate_loop_exit_test PARAMS ((rtx));
118 static void find_cross_jump PARAMS ((rtx, rtx, int, rtx *, rtx *));
119 static void do_cross_jump PARAMS ((rtx, rtx, rtx));
120 static int jump_back_p PARAMS ((rtx, rtx));
121 static int tension_vector_labels PARAMS ((rtx, int));
122 static void mark_jump_label PARAMS ((rtx, rtx, int, int));
123 static void delete_computation PARAMS ((rtx));
124 static void redirect_exp_1 PARAMS ((rtx *, rtx, rtx, rtx));
125 static void invert_exp_1 PARAMS ((rtx, rtx));
126 static void delete_from_jump_chain PARAMS ((rtx));
127 static int delete_labelref_insn PARAMS ((rtx, rtx, int));
128 static void mark_modified_reg PARAMS ((rtx, rtx, void *));
129 static void redirect_tablejump PARAMS ((rtx, rtx));
130 static void jump_optimize_1 PARAMS ((rtx, int, int, int, int, int));
131 #if ! defined(HAVE_cc0) && ! defined(HAVE_conditional_arithmetic)
132 static rtx find_insert_position PARAMS ((rtx, rtx));
134 static int returnjump_p_1 PARAMS ((rtx *, void *));
135 static void delete_prior_computation PARAMS ((rtx, rtx));
137 /* Main external entry point into the jump optimizer. See comments before
138 jump_optimize_1 for descriptions of the arguments. */
140 jump_optimize (f, cross_jump, noop_moves, after_regscan)
146 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, 0, 0);
149 /* Alternate entry into the jump optimizer. This entry point only rebuilds
150 the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
153 rebuild_jump_labels (f)
156 jump_optimize_1 (f, 0, 0, 0, 1, 0);
159 /* Alternate entry into the jump optimizer. Do only trivial optimizations. */
161 jump_optimize_minimal (f)
164 jump_optimize_1 (f, 0, 0, 0, 0, 1);
167 /* Delete no-op jumps and optimize jumps to jumps
168 and jumps around jumps.
169 Delete unused labels and unreachable code.
171 If CROSS_JUMP is 1, detect matching code
172 before a jump and its destination and unify them.
173 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
175 If NOOP_MOVES is nonzero, delete no-op move insns.
177 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
178 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
180 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
181 and JUMP_LABEL field for jumping insns.
183 If `optimize' is zero, don't change any code,
184 just determine whether control drops off the end of the function.
185 This case occurs when we have -W and not -O.
186 It works because `delete_insn' checks the value of `optimize'
187 and refrains from actually deleting when that is 0.
189 If MINIMAL is nonzero, then we only perform trivial optimizations:
191 * Removal of unreachable code after BARRIERs.
192 * Removal of unreferenced CODE_LABELs.
193 * Removal of a jump to the next instruction.
194 * Removal of a conditional jump followed by an unconditional jump
195 to the same target as the conditional jump.
196 * Simplify a conditional jump around an unconditional jump.
197 * Simplify a jump to a jump.
198 * Delete extraneous line number notes.
202 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan,
203 mark_labels_only, minimal)
208 int mark_labels_only;
211 register rtx insn, next;
218 cross_jump_death_matters = (cross_jump == 2);
219 max_uid = init_label_info (f) + 1;
221 /* If we are performing cross jump optimizations, then initialize
222 tables mapping UIDs to EH regions to avoid incorrect movement
223 of insns from one EH region to another. */
224 if (flag_exceptions && cross_jump)
225 init_insn_eh_region (f, max_uid);
227 if (! mark_labels_only)
228 delete_barrier_successors (f);
230 /* Leave some extra room for labels and duplicate exit test insns
232 max_jump_chain = max_uid * 14 / 10;
233 jump_chain = (rtx *) xcalloc (max_jump_chain, sizeof (rtx));
235 mark_all_labels (f, cross_jump);
237 /* Keep track of labels used from static data;
238 they cannot ever be deleted. */
240 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
241 LABEL_NUSES (XEXP (insn, 0))++;
243 check_exception_handler_labels ();
245 /* Keep track of labels used for marking handlers for exception
246 regions; they cannot usually be deleted. */
248 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
249 LABEL_NUSES (XEXP (insn, 0))++;
251 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
252 notes and recompute LABEL_NUSES. */
253 if (mark_labels_only)
257 exception_optimize ();
259 last_insn = delete_unreferenced_labels (f);
262 delete_noop_moves (f);
264 /* If we haven't yet gotten to reload and we have just run regscan,
265 delete any insn that sets a register that isn't used elsewhere.
266 This helps some of the optimizations below by having less insns
267 being jumped around. */
269 if (optimize && ! reload_completed && after_regscan)
270 for (insn = f; insn; insn = next)
272 rtx set = single_set (insn);
274 next = NEXT_INSN (insn);
276 if (set && GET_CODE (SET_DEST (set)) == REG
277 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
278 && REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
279 /* We use regno_last_note_uid so as not to delete the setting
280 of a reg that's used in notes. A subsequent optimization
281 might arrange to use that reg for real. */
282 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
283 && ! side_effects_p (SET_SRC (set))
284 && ! find_reg_note (insn, REG_RETVAL, 0)
285 /* An ADDRESSOF expression can turn into a use of the internal arg
286 pointer, so do not delete the initialization of the internal
287 arg pointer yet. If it is truly dead, flow will delete the
288 initializing insn. */
289 && SET_DEST (set) != current_function_internal_arg_pointer)
293 /* Now iterate optimizing jumps until nothing changes over one pass. */
295 old_max_reg = max_reg_num ();
300 for (insn = f; insn; insn = next)
303 rtx temp, temp1, temp2 = NULL_RTX, temp3, temp4, temp5, temp6;
305 int this_is_simplejump, this_is_condjump, reversep = 0;
306 int this_is_condjump_in_parallel;
308 next = NEXT_INSN (insn);
310 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
311 jump. Try to optimize by duplicating the loop exit test if so.
312 This is only safe immediately after regscan, because it uses
313 the values of regno_first_uid and regno_last_uid. */
314 if (after_regscan && GET_CODE (insn) == NOTE
315 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
316 && (temp1 = next_nonnote_insn (insn)) != 0
317 && simplejump_p (temp1))
319 temp = PREV_INSN (insn);
320 if (duplicate_loop_exit_test (insn))
323 next = NEXT_INSN (temp);
328 if (GET_CODE (insn) != JUMP_INSN)
331 this_is_simplejump = simplejump_p (insn);
332 this_is_condjump = condjump_p (insn);
333 this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
335 /* Tension the labels in dispatch tables. */
337 if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
338 changed |= tension_vector_labels (PATTERN (insn), 0);
339 if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
340 changed |= tension_vector_labels (PATTERN (insn), 1);
342 /* See if this jump goes to another jump and redirect if so. */
343 nlabel = follow_jumps (JUMP_LABEL (insn));
344 if (nlabel != JUMP_LABEL (insn))
345 changed |= redirect_jump (insn, nlabel);
347 if (! optimize || minimal)
350 /* If a dispatch table always goes to the same place,
351 get rid of it and replace the insn that uses it. */
353 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
354 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
357 rtx pat = PATTERN (insn);
358 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
359 int len = XVECLEN (pat, diff_vec_p);
360 rtx dispatch = prev_real_insn (insn);
363 for (i = 0; i < len; i++)
364 if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
365 != XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
370 && GET_CODE (dispatch) == JUMP_INSN
371 && JUMP_LABEL (dispatch) != 0
372 /* Don't mess with a casesi insn.
373 XXX according to the comment before computed_jump_p(),
374 all casesi insns should be a parallel of the jump
375 and a USE of a LABEL_REF. */
376 && ! ((set = single_set (dispatch)) != NULL
377 && (GET_CODE (SET_SRC (set)) == IF_THEN_ELSE))
378 && next_real_insn (JUMP_LABEL (dispatch)) == insn)
380 redirect_tablejump (dispatch,
381 XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
386 /* If a jump references the end of the function, try to turn
387 it into a RETURN insn, possibly a conditional one. */
388 if (JUMP_LABEL (insn) != 0
389 && (next_active_insn (JUMP_LABEL (insn)) == 0
390 || GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn))))
392 changed |= redirect_jump (insn, NULL_RTX);
394 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
396 /* Detect jump to following insn. */
397 if (reallabelprev == insn && this_is_condjump)
399 next = next_real_insn (JUMP_LABEL (insn));
405 /* Detect a conditional jump going to the same place
406 as an immediately following unconditional jump. */
407 else if (this_is_condjump
408 && (temp = next_active_insn (insn)) != 0
409 && simplejump_p (temp)
410 && (next_active_insn (JUMP_LABEL (insn))
411 == next_active_insn (JUMP_LABEL (temp))))
413 /* Don't mess up test coverage analysis. */
415 if (flag_test_coverage && !reload_completed)
416 for (temp2 = insn; temp2 != temp; temp2 = NEXT_INSN (temp2))
417 if (GET_CODE (temp2) == NOTE && NOTE_LINE_NUMBER (temp2) > 0)
428 /* Detect a conditional jump jumping over an unconditional jump. */
430 else if ((this_is_condjump || this_is_condjump_in_parallel)
431 && ! this_is_simplejump
432 && reallabelprev != 0
433 && GET_CODE (reallabelprev) == JUMP_INSN
434 && prev_active_insn (reallabelprev) == insn
435 && no_labels_between_p (insn, reallabelprev)
436 && simplejump_p (reallabelprev))
438 /* When we invert the unconditional jump, we will be
439 decrementing the usage count of its old label.
440 Make sure that we don't delete it now because that
441 might cause the following code to be deleted. */
442 rtx prev_uses = prev_nonnote_insn (reallabelprev);
443 rtx prev_label = JUMP_LABEL (insn);
446 ++LABEL_NUSES (prev_label);
448 if (invert_jump (insn, JUMP_LABEL (reallabelprev)))
450 /* It is very likely that if there are USE insns before
451 this jump, they hold REG_DEAD notes. These REG_DEAD
452 notes are no longer valid due to this optimization,
453 and will cause the life-analysis that following passes
454 (notably delayed-branch scheduling) to think that
455 these registers are dead when they are not.
457 To prevent this trouble, we just remove the USE insns
458 from the insn chain. */
460 while (prev_uses && GET_CODE (prev_uses) == INSN
461 && GET_CODE (PATTERN (prev_uses)) == USE)
463 rtx useless = prev_uses;
464 prev_uses = prev_nonnote_insn (prev_uses);
465 delete_insn (useless);
468 delete_insn (reallabelprev);
472 /* We can now safely delete the label if it is unreferenced
473 since the delete_insn above has deleted the BARRIER. */
474 if (prev_label && --LABEL_NUSES (prev_label) == 0)
475 delete_insn (prev_label);
477 next = NEXT_INSN (insn);
480 /* If we have an unconditional jump preceded by a USE, try to put
481 the USE before the target and jump there. This simplifies many
482 of the optimizations below since we don't have to worry about
483 dealing with these USE insns. We only do this if the label
484 being branch to already has the identical USE or if code
485 never falls through to that label. */
487 else if (this_is_simplejump
488 && (temp = prev_nonnote_insn (insn)) != 0
489 && GET_CODE (temp) == INSN
490 && GET_CODE (PATTERN (temp)) == USE
491 && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
492 && (GET_CODE (temp1) == BARRIER
493 || (GET_CODE (temp1) == INSN
494 && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
495 /* Don't do this optimization if we have a loop containing
496 only the USE instruction, and the loop start label has
497 a usage count of 1. This is because we will redo this
498 optimization everytime through the outer loop, and jump
499 opt will never exit. */
500 && ! ((temp2 = prev_nonnote_insn (temp)) != 0
501 && temp2 == JUMP_LABEL (insn)
502 && LABEL_NUSES (temp2) == 1))
504 if (GET_CODE (temp1) == BARRIER)
506 emit_insn_after (PATTERN (temp), temp1);
507 temp1 = NEXT_INSN (temp1);
511 redirect_jump (insn, get_label_before (temp1));
512 reallabelprev = prev_real_insn (temp1);
514 next = NEXT_INSN (insn);
517 /* Simplify if (...) x = a; else x = b; by converting it
518 to x = b; if (...) x = a;
519 if B is sufficiently simple, the test doesn't involve X,
520 and nothing in the test modifies B or X.
522 If we have small register classes, we also can't do this if X
525 If the "x = b;" insn has any REG_NOTES, we don't do this because
526 of the possibility that we are running after CSE and there is a
527 REG_EQUAL note that is only valid if the branch has already been
528 taken. If we move the insn with the REG_EQUAL note, we may
529 fold the comparison to always be false in a later CSE pass.
530 (We could also delete the REG_NOTES when moving the insn, but it
531 seems simpler to not move it.) An exception is that we can move
532 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
533 value is the same as "b".
535 INSN is the branch over the `else' part.
539 TEMP to the jump insn preceding "x = a;"
541 TEMP2 to the insn that sets "x = b;"
542 TEMP3 to the insn that sets "x = a;"
543 TEMP4 to the set of "x = b"; */
545 if (this_is_simplejump
546 && (temp3 = prev_active_insn (insn)) != 0
547 && GET_CODE (temp3) == INSN
548 && (temp4 = single_set (temp3)) != 0
549 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
550 && (! SMALL_REGISTER_CLASSES
551 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
552 && (temp2 = next_active_insn (insn)) != 0
553 && GET_CODE (temp2) == INSN
554 && (temp4 = single_set (temp2)) != 0
555 && rtx_equal_p (SET_DEST (temp4), temp1)
556 && ! side_effects_p (SET_SRC (temp4))
557 && ! may_trap_p (SET_SRC (temp4))
558 && (REG_NOTES (temp2) == 0
559 || ((REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUAL
560 || REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUIV)
561 && XEXP (REG_NOTES (temp2), 1) == 0
562 && rtx_equal_p (XEXP (REG_NOTES (temp2), 0),
564 && (temp = prev_active_insn (temp3)) != 0
565 && condjump_p (temp) && ! simplejump_p (temp)
566 /* TEMP must skip over the "x = a;" insn */
567 && prev_real_insn (JUMP_LABEL (temp)) == insn
568 && no_labels_between_p (insn, JUMP_LABEL (temp))
569 /* There must be no other entries to the "x = b;" insn. */
570 && no_labels_between_p (JUMP_LABEL (temp), temp2)
571 /* INSN must either branch to the insn after TEMP2 or the insn
572 after TEMP2 must branch to the same place as INSN. */
573 && (reallabelprev == temp2
574 || ((temp5 = next_active_insn (temp2)) != 0
575 && simplejump_p (temp5)
576 && JUMP_LABEL (temp5) == JUMP_LABEL (insn))))
578 /* The test expression, X, may be a complicated test with
579 multiple branches. See if we can find all the uses of
580 the label that TEMP branches to without hitting a CALL_INSN
581 or a jump to somewhere else. */
582 rtx target = JUMP_LABEL (temp);
583 int nuses = LABEL_NUSES (target);
589 /* Set P to the first jump insn that goes around "x = a;". */
590 for (p = temp; nuses && p; p = prev_nonnote_insn (p))
592 if (GET_CODE (p) == JUMP_INSN)
594 if (condjump_p (p) && ! simplejump_p (p)
595 && JUMP_LABEL (p) == target)
604 else if (GET_CODE (p) == CALL_INSN)
609 /* We cannot insert anything between a set of cc and its use
610 so if P uses cc0, we must back up to the previous insn. */
611 q = prev_nonnote_insn (p);
612 if (q && GET_RTX_CLASS (GET_CODE (q)) == 'i'
613 && sets_cc0_p (PATTERN (q)))
620 /* If we found all the uses and there was no data conflict, we
621 can move the assignment unless we can branch into the middle
624 && no_labels_between_p (p, insn)
625 && ! reg_referenced_between_p (temp1, p, NEXT_INSN (temp3))
626 && ! reg_set_between_p (temp1, p, temp3)
627 && (GET_CODE (SET_SRC (temp4)) == CONST_INT
628 || ! modified_between_p (SET_SRC (temp4), p, temp2))
629 /* Verify that registers used by the jump are not clobbered
630 by the instruction being moved. */
631 && ! regs_set_between_p (PATTERN (temp),
635 emit_insn_after_with_line_notes (PATTERN (temp2), p, temp2);
638 /* Set NEXT to an insn that we know won't go away. */
639 next = next_active_insn (insn);
641 /* Delete the jump around the set. Note that we must do
642 this before we redirect the test jumps so that it won't
643 delete the code immediately following the assignment
644 we moved (which might be a jump). */
648 /* We either have two consecutive labels or a jump to
649 a jump, so adjust all the JUMP_INSNs to branch to where
651 for (p = NEXT_INSN (p); p != next; p = NEXT_INSN (p))
652 if (GET_CODE (p) == JUMP_INSN)
653 redirect_jump (p, target);
656 next = NEXT_INSN (insn);
661 /* Simplify if (...) { x = a; goto l; } x = b; by converting it
662 to x = a; if (...) goto l; x = b;
663 if A is sufficiently simple, the test doesn't involve X,
664 and nothing in the test modifies A or X.
666 If we have small register classes, we also can't do this if X
669 If the "x = a;" insn has any REG_NOTES, we don't do this because
670 of the possibility that we are running after CSE and there is a
671 REG_EQUAL note that is only valid if the branch has already been
672 taken. If we move the insn with the REG_EQUAL note, we may
673 fold the comparison to always be false in a later CSE pass.
674 (We could also delete the REG_NOTES when moving the insn, but it
675 seems simpler to not move it.) An exception is that we can move
676 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
677 value is the same as "a".
683 TEMP to the jump insn preceding "x = a;"
685 TEMP2 to the insn that sets "x = b;"
686 TEMP3 to the insn that sets "x = a;"
687 TEMP4 to the set of "x = a"; */
689 if (this_is_simplejump
690 && (temp2 = next_active_insn (insn)) != 0
691 && GET_CODE (temp2) == INSN
692 && (temp4 = single_set (temp2)) != 0
693 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
694 && (! SMALL_REGISTER_CLASSES
695 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
696 && (temp3 = prev_active_insn (insn)) != 0
697 && GET_CODE (temp3) == INSN
698 && (temp4 = single_set (temp3)) != 0
699 && rtx_equal_p (SET_DEST (temp4), temp1)
700 && ! side_effects_p (SET_SRC (temp4))
701 && ! may_trap_p (SET_SRC (temp4))
702 && (REG_NOTES (temp3) == 0
703 || ((REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUAL
704 || REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUIV)
705 && XEXP (REG_NOTES (temp3), 1) == 0
706 && rtx_equal_p (XEXP (REG_NOTES (temp3), 0),
708 && (temp = prev_active_insn (temp3)) != 0
709 && condjump_p (temp) && ! simplejump_p (temp)
710 /* TEMP must skip over the "x = a;" insn */
711 && prev_real_insn (JUMP_LABEL (temp)) == insn
712 && no_labels_between_p (temp, insn))
714 rtx prev_label = JUMP_LABEL (temp);
715 rtx insert_after = prev_nonnote_insn (temp);
718 /* We cannot insert anything between a set of cc and its use. */
719 if (insert_after && GET_RTX_CLASS (GET_CODE (insert_after)) == 'i'
720 && sets_cc0_p (PATTERN (insert_after)))
721 insert_after = prev_nonnote_insn (insert_after);
723 ++LABEL_NUSES (prev_label);
726 && no_labels_between_p (insert_after, temp)
727 && ! reg_referenced_between_p (temp1, insert_after, temp3)
728 && ! reg_referenced_between_p (temp1, temp3,
730 && ! reg_set_between_p (temp1, insert_after, temp)
731 && ! modified_between_p (SET_SRC (temp4), insert_after, temp)
732 /* Verify that registers used by the jump are not clobbered
733 by the instruction being moved. */
734 && ! regs_set_between_p (PATTERN (temp),
737 && invert_jump (temp, JUMP_LABEL (insn)))
739 emit_insn_after_with_line_notes (PATTERN (temp3),
740 insert_after, temp3);
743 /* Set NEXT to an insn that we know won't go away. */
747 if (prev_label && --LABEL_NUSES (prev_label) == 0)
748 delete_insn (prev_label);
753 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
755 /* If we have if (...) x = exp; and branches are expensive,
756 EXP is a single insn, does not have any side effects, cannot
757 trap, and is not too costly, convert this to
758 t = exp; if (...) x = t;
760 Don't do this when we have CC0 because it is unlikely to help
761 and we'd need to worry about where to place the new insn and
762 the potential for conflicts. We also can't do this when we have
763 notes on the insn for the same reason as above.
765 If we have conditional arithmetic, this will make this
766 harder to optimize later and isn't needed, so don't do it
771 TEMP to the "x = exp;" insn.
772 TEMP1 to the single set in the "x = exp;" insn.
775 if (! reload_completed
776 && this_is_condjump && ! this_is_simplejump
778 && (temp = next_nonnote_insn (insn)) != 0
779 && GET_CODE (temp) == INSN
780 && REG_NOTES (temp) == 0
781 && (reallabelprev == temp
782 || ((temp2 = next_active_insn (temp)) != 0
783 && simplejump_p (temp2)
784 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
785 && (temp1 = single_set (temp)) != 0
786 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
787 && (! SMALL_REGISTER_CLASSES
788 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
789 && GET_CODE (SET_SRC (temp1)) != REG
790 && GET_CODE (SET_SRC (temp1)) != SUBREG
791 && GET_CODE (SET_SRC (temp1)) != CONST_INT
792 && ! side_effects_p (SET_SRC (temp1))
793 && ! may_trap_p (SET_SRC (temp1))
794 && rtx_cost (SET_SRC (temp1), SET) < 10)
796 rtx new = gen_reg_rtx (GET_MODE (temp2));
798 if ((temp3 = find_insert_position (insn, temp))
799 && validate_change (temp, &SET_DEST (temp1), new, 0))
801 next = emit_insn_after (gen_move_insn (temp2, new), insn);
802 emit_insn_after_with_line_notes (PATTERN (temp),
803 PREV_INSN (temp3), temp);
805 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
809 reg_scan_update (temp3, NEXT_INSN (next), old_max_reg);
810 old_max_reg = max_reg_num ();
815 /* Similarly, if it takes two insns to compute EXP but they
816 have the same destination. Here TEMP3 will be the second
817 insn and TEMP4 the SET from that insn. */
819 if (! reload_completed
820 && this_is_condjump && ! this_is_simplejump
822 && (temp = next_nonnote_insn (insn)) != 0
823 && GET_CODE (temp) == INSN
824 && REG_NOTES (temp) == 0
825 && (temp3 = next_nonnote_insn (temp)) != 0
826 && GET_CODE (temp3) == INSN
827 && REG_NOTES (temp3) == 0
828 && (reallabelprev == temp3
829 || ((temp2 = next_active_insn (temp3)) != 0
830 && simplejump_p (temp2)
831 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
832 && (temp1 = single_set (temp)) != 0
833 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
834 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
835 && (! SMALL_REGISTER_CLASSES
836 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
837 && ! side_effects_p (SET_SRC (temp1))
838 && ! may_trap_p (SET_SRC (temp1))
839 && rtx_cost (SET_SRC (temp1), SET) < 10
840 && (temp4 = single_set (temp3)) != 0
841 && rtx_equal_p (SET_DEST (temp4), temp2)
842 && ! side_effects_p (SET_SRC (temp4))
843 && ! may_trap_p (SET_SRC (temp4))
844 && rtx_cost (SET_SRC (temp4), SET) < 10)
846 rtx new = gen_reg_rtx (GET_MODE (temp2));
848 if ((temp5 = find_insert_position (insn, temp))
849 && (temp6 = find_insert_position (insn, temp3))
850 && validate_change (temp, &SET_DEST (temp1), new, 0))
852 /* Use the earliest of temp5 and temp6. */
855 next = emit_insn_after (gen_move_insn (temp2, new), insn);
856 emit_insn_after_with_line_notes (PATTERN (temp),
857 PREV_INSN (temp6), temp);
858 emit_insn_after_with_line_notes
859 (replace_rtx (PATTERN (temp3), temp2, new),
860 PREV_INSN (temp6), temp3);
863 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
867 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
868 old_max_reg = max_reg_num ();
873 /* Finally, handle the case where two insns are used to
874 compute EXP but a temporary register is used. Here we must
875 ensure that the temporary register is not used anywhere else. */
877 if (! reload_completed
879 && this_is_condjump && ! this_is_simplejump
881 && (temp = next_nonnote_insn (insn)) != 0
882 && GET_CODE (temp) == INSN
883 && REG_NOTES (temp) == 0
884 && (temp3 = next_nonnote_insn (temp)) != 0
885 && GET_CODE (temp3) == INSN
886 && REG_NOTES (temp3) == 0
887 && (reallabelprev == temp3
888 || ((temp2 = next_active_insn (temp3)) != 0
889 && simplejump_p (temp2)
890 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
891 && (temp1 = single_set (temp)) != 0
892 && (temp5 = SET_DEST (temp1),
893 (GET_CODE (temp5) == REG
894 || (GET_CODE (temp5) == SUBREG
895 && (temp5 = SUBREG_REG (temp5),
896 GET_CODE (temp5) == REG))))
897 && REGNO (temp5) >= FIRST_PSEUDO_REGISTER
898 && REGNO_FIRST_UID (REGNO (temp5)) == INSN_UID (temp)
899 && REGNO_LAST_UID (REGNO (temp5)) == INSN_UID (temp3)
900 && ! side_effects_p (SET_SRC (temp1))
901 && ! may_trap_p (SET_SRC (temp1))
902 && rtx_cost (SET_SRC (temp1), SET) < 10
903 && (temp4 = single_set (temp3)) != 0
904 && (temp2 = SET_DEST (temp4), GET_CODE (temp2) == REG)
905 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
906 && (! SMALL_REGISTER_CLASSES
907 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
908 && rtx_equal_p (SET_DEST (temp4), temp2)
909 && ! side_effects_p (SET_SRC (temp4))
910 && ! may_trap_p (SET_SRC (temp4))
911 && rtx_cost (SET_SRC (temp4), SET) < 10)
913 rtx new = gen_reg_rtx (GET_MODE (temp2));
915 if ((temp5 = find_insert_position (insn, temp))
916 && (temp6 = find_insert_position (insn, temp3))
917 && validate_change (temp3, &SET_DEST (temp4), new, 0))
919 /* Use the earliest of temp5 and temp6. */
922 next = emit_insn_after (gen_move_insn (temp2, new), insn);
923 emit_insn_after_with_line_notes (PATTERN (temp),
924 PREV_INSN (temp6), temp);
925 emit_insn_after_with_line_notes (PATTERN (temp3),
926 PREV_INSN (temp6), temp3);
929 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
933 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
934 old_max_reg = max_reg_num ();
938 #endif /* HAVE_cc0 */
940 #ifdef HAVE_conditional_arithmetic
941 /* ??? This is disabled in genconfig, as this simple-minded
942 transformation can incredibly lengthen register lifetimes.
944 Consider this example:
947 (if_then_else (ne (reg:DI 149) (const_int 0 [0x0]))
948 (label_ref 248) (pc)))
949 237 (set (reg/i:DI 0 $0) (const_int 1 [0x1]))
950 239 (set (pc) (label_ref 2382))
951 248 (code_label ("yybackup"))
953 This will be transformed to:
955 237 (set (reg/i:DI 0 $0)
956 (if_then_else:DI (eq (reg:DI 149) (const_int 0 [0x0]))
957 (const_int 1 [0x1]) (reg/i:DI 0 $0)))
959 (if_then_else (eq (reg:DI 149) (const_int 0 [0x0]))
960 (label_ref 2382) (pc)))
962 which, from this narrow viewpoint looks fine. Except that
963 between this and 3 other ocurrences of the same pattern, $0
964 is now live for basically the entire function, and we'll
965 get an abort in caller_save.
967 Any replacement for this code should recall that a set of
968 a register that is not live need not, and indeed should not,
969 be conditionalized. Either that, or delay the transformation
970 until after register allocation. */
972 /* See if this is a conditional jump around a small number of
973 instructions that we can conditionalize. Don't do this before
974 the initial CSE pass or after reload.
976 We reject any insns that have side effects or may trap.
977 Strictly speaking, this is not needed since the machine may
978 support conditionalizing these too, but we won't deal with that
979 now. Specifically, this means that we can't conditionalize a
980 CALL_INSN, which some machines, such as the ARC, can do, but
981 this is a very minor optimization. */
982 if (this_is_condjump && ! this_is_simplejump
983 && cse_not_expected && ! reload_completed
985 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (insn)), 0),
988 rtx ourcond = XEXP (SET_SRC (PATTERN (insn)), 0);
990 char *storage = (char *) oballoc (0);
991 int last_insn = 0, failed = 0;
992 rtx changed_jump = 0;
994 ourcond = gen_rtx (reverse_condition (GET_CODE (ourcond)),
995 VOIDmode, XEXP (ourcond, 0),
998 /* Scan forward BRANCH_COST real insns looking for the JUMP_LABEL
999 of this insn. We see if we think we can conditionalize the
1000 insns we pass. For now, we only deal with insns that have
1001 one SET. We stop after an insn that modifies anything in
1002 OURCOND, if we have too many insns, or if we have an insn
1003 with a side effect or that may trip. Note that we will
1004 be modifying any unconditional jumps we encounter to be
1005 conditional; this will have the effect of also doing this
1006 optimization on the "else" the next time around. */
1007 for (temp1 = NEXT_INSN (insn);
1008 num_insns <= BRANCH_COST && ! failed && temp1 != 0
1009 && GET_CODE (temp1) != CODE_LABEL;
1010 temp1 = NEXT_INSN (temp1))
1012 /* Ignore everything but an active insn. */
1013 if (GET_RTX_CLASS (GET_CODE (temp1)) != 'i'
1014 || GET_CODE (PATTERN (temp1)) == USE
1015 || GET_CODE (PATTERN (temp1)) == CLOBBER)
1018 /* If this was an unconditional jump, record it since we'll
1019 need to remove the BARRIER if we succeed. We can only
1020 have one such jump since there must be a label after
1021 the BARRIER and it's either ours, in which case it's the
1022 only one or some other, in which case we'd fail.
1023 Likewise if it's a CALL_INSN followed by a BARRIER. */
1025 if (simplejump_p (temp1)
1026 || (GET_CODE (temp1) == CALL_INSN
1027 && NEXT_INSN (temp1) != 0
1028 && GET_CODE (NEXT_INSN (temp1)) == BARRIER))
1030 if (changed_jump == 0)
1031 changed_jump = temp1;
1034 = gen_rtx_INSN_LIST (VOIDmode, temp1, changed_jump);
1037 /* See if we are allowed another insn and if this insn
1038 if one we think we may be able to handle. */
1039 if (++num_insns > BRANCH_COST
1041 || (((temp2 = single_set (temp1)) == 0
1042 || side_effects_p (SET_SRC (temp2))
1043 || may_trap_p (SET_SRC (temp2)))
1044 && GET_CODE (temp1) != CALL_INSN))
1046 else if (temp2 != 0)
1047 validate_change (temp1, &SET_SRC (temp2),
1048 gen_rtx_IF_THEN_ELSE
1049 (GET_MODE (SET_DEST (temp2)),
1051 SET_SRC (temp2), SET_DEST (temp2)),
1055 /* This is a CALL_INSN that doesn't have a SET. */
1056 rtx *call_loc = &PATTERN (temp1);
1058 if (GET_CODE (*call_loc) == PARALLEL)
1059 call_loc = &XVECEXP (*call_loc, 0, 0);
1061 validate_change (temp1, call_loc,
1062 gen_rtx_IF_THEN_ELSE
1063 (VOIDmode, copy_rtx (ourcond),
1064 *call_loc, const0_rtx),
1069 if (modified_in_p (ourcond, temp1))
1073 /* If we've reached our jump label, haven't failed, and all
1074 the changes above are valid, we can delete this jump
1075 insn. Also remove a BARRIER after any jump that used
1076 to be unconditional and remove any REG_EQUAL or REG_EQUIV
1077 that might have previously been present on insns we
1078 made conditional. */
1079 if (temp1 == JUMP_LABEL (insn) && ! failed
1080 && apply_change_group ())
1082 for (temp1 = NEXT_INSN (insn); temp1 != JUMP_LABEL (insn);
1083 temp1 = NEXT_INSN (temp1))
1084 if (GET_RTX_CLASS (GET_CODE (temp1)) == 'i')
1085 for (temp2 = REG_NOTES (temp1); temp2 != 0;
1086 temp2 = XEXP (temp2, 1))
1087 if (REG_NOTE_KIND (temp2) == REG_EQUAL
1088 || REG_NOTE_KIND (temp2) == REG_EQUIV)
1089 remove_note (temp1, temp2);
1091 if (changed_jump != 0)
1093 while (GET_CODE (changed_jump) == INSN_LIST)
1095 delete_barrier (NEXT_INSN (XEXP (changed_jump, 0)));
1096 changed_jump = XEXP (changed_jump, 1);
1099 delete_barrier (NEXT_INSN (changed_jump));
1113 /* If branches are expensive, convert
1114 if (foo) bar++; to bar += (foo != 0);
1115 and similarly for "bar--;"
1117 INSN is the conditional branch around the arithmetic. We set:
1119 TEMP is the arithmetic insn.
1120 TEMP1 is the SET doing the arithmetic.
1121 TEMP2 is the operand being incremented or decremented.
1122 TEMP3 to the condition being tested.
1123 TEMP4 to the earliest insn used to find the condition. */
1125 if ((BRANCH_COST >= 2
1133 && ! reload_completed
1134 && this_is_condjump && ! this_is_simplejump
1135 && (temp = next_nonnote_insn (insn)) != 0
1136 && (temp1 = single_set (temp)) != 0
1137 && (temp2 = SET_DEST (temp1),
1138 GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT)
1139 && GET_CODE (SET_SRC (temp1)) == PLUS
1140 && (XEXP (SET_SRC (temp1), 1) == const1_rtx
1141 || XEXP (SET_SRC (temp1), 1) == constm1_rtx)
1142 && rtx_equal_p (temp2, XEXP (SET_SRC (temp1), 0))
1143 && ! side_effects_p (temp2)
1144 && ! may_trap_p (temp2)
1145 /* INSN must either branch to the insn after TEMP or the insn
1146 after TEMP must branch to the same place as INSN. */
1147 && (reallabelprev == temp
1148 || ((temp3 = next_active_insn (temp)) != 0
1149 && simplejump_p (temp3)
1150 && JUMP_LABEL (temp3) == JUMP_LABEL (insn)))
1151 && (temp3 = get_condition (insn, &temp4)) != 0
1152 /* We must be comparing objects whose modes imply the size.
1153 We could handle BLKmode if (1) emit_store_flag could
1154 and (2) we could find the size reliably. */
1155 && GET_MODE (XEXP (temp3, 0)) != BLKmode
1156 && can_reverse_comparison_p (temp3, insn))
1158 rtx temp6, target = 0, seq, init_insn = 0, init = temp2;
1159 enum rtx_code code = reverse_condition (GET_CODE (temp3));
1163 /* It must be the case that TEMP2 is not modified in the range
1164 [TEMP4, INSN). The one exception we make is if the insn
1165 before INSN sets TEMP2 to something which is also unchanged
1166 in that range. In that case, we can move the initialization
1167 into our sequence. */
1169 if ((temp5 = prev_active_insn (insn)) != 0
1170 && no_labels_between_p (temp5, insn)
1171 && GET_CODE (temp5) == INSN
1172 && (temp6 = single_set (temp5)) != 0
1173 && rtx_equal_p (temp2, SET_DEST (temp6))
1174 && (CONSTANT_P (SET_SRC (temp6))
1175 || GET_CODE (SET_SRC (temp6)) == REG
1176 || GET_CODE (SET_SRC (temp6)) == SUBREG))
1178 emit_insn (PATTERN (temp5));
1180 init = SET_SRC (temp6);
1183 if (CONSTANT_P (init)
1184 || ! reg_set_between_p (init, PREV_INSN (temp4), insn))
1185 target = emit_store_flag (gen_reg_rtx (GET_MODE (temp2)), code,
1186 XEXP (temp3, 0), XEXP (temp3, 1),
1188 (code == LTU || code == LEU
1189 || code == GTU || code == GEU), 1);
1191 /* If we can do the store-flag, do the addition or
1195 target = expand_binop (GET_MODE (temp2),
1196 (XEXP (SET_SRC (temp1), 1) == const1_rtx
1197 ? add_optab : sub_optab),
1198 temp2, target, temp2, 0, OPTAB_WIDEN);
1202 /* Put the result back in temp2 in case it isn't already.
1203 Then replace the jump, possible a CC0-setting insn in
1204 front of the jump, and TEMP, with the sequence we have
1207 if (target != temp2)
1208 emit_move_insn (temp2, target);
1213 emit_insns_before (seq, temp4);
1217 delete_insn (init_insn);
1219 next = NEXT_INSN (insn);
1221 delete_insn (prev_nonnote_insn (insn));
1227 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1228 old_max_reg = max_reg_num ();
1238 /* Try to use a conditional move (if the target has them), or a
1239 store-flag insn. If the target has conditional arithmetic as
1240 well as conditional move, the above code will have done something.
1241 Note that we prefer the above code since it is more general: the
1242 code below can make changes that require work to undo.
1244 The general case here is:
1246 1) x = a; if (...) x = b; and
1249 If the jump would be faster, the machine should not have defined
1250 the movcc or scc insns!. These cases are often made by the
1251 previous optimization.
1253 The second case is treated as x = x; if (...) x = b;.
1255 INSN here is the jump around the store. We set:
1257 TEMP to the "x op= b;" insn.
1260 TEMP3 to A (X in the second case).
1261 TEMP4 to the condition being tested.
1262 TEMP5 to the earliest insn used to find the condition.
1263 TEMP6 to the SET of TEMP. */
1265 if (/* We can't do this after reload has completed. */
1267 #ifdef HAVE_conditional_arithmetic
1268 /* Defer this until after CSE so the above code gets the
1269 first crack at it. */
1272 && this_is_condjump && ! this_is_simplejump
1273 /* Set TEMP to the "x = b;" insn. */
1274 && (temp = next_nonnote_insn (insn)) != 0
1275 && GET_CODE (temp) == INSN
1276 && (temp6 = single_set (temp)) != NULL_RTX
1277 && GET_CODE (temp1 = SET_DEST (temp6)) == REG
1278 && (! SMALL_REGISTER_CLASSES
1279 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
1280 && ! side_effects_p (temp2 = SET_SRC (temp6))
1281 && ! may_trap_p (temp2)
1282 /* Allow either form, but prefer the former if both apply.
1283 There is no point in using the old value of TEMP1 if
1284 it is a register, since cse will alias them. It can
1285 lose if the old value were a hard register since CSE
1286 won't replace hard registers. Avoid using TEMP3 if
1287 small register classes and it is a hard register. */
1288 && (((temp3 = reg_set_last (temp1, insn)) != 0
1289 && ! (SMALL_REGISTER_CLASSES && GET_CODE (temp3) == REG
1290 && REGNO (temp3) < FIRST_PSEUDO_REGISTER))
1291 /* Make the latter case look like x = x; if (...) x = b; */
1292 || (temp3 = temp1, 1))
1293 /* INSN must either branch to the insn after TEMP or the insn
1294 after TEMP must branch to the same place as INSN. */
1295 && (reallabelprev == temp
1296 || ((temp4 = next_active_insn (temp)) != 0
1297 && simplejump_p (temp4)
1298 && JUMP_LABEL (temp4) == JUMP_LABEL (insn)))
1299 && (temp4 = get_condition (insn, &temp5)) != 0
1300 /* We must be comparing objects whose modes imply the size.
1301 We could handle BLKmode if (1) emit_store_flag could
1302 and (2) we could find the size reliably. */
1303 && GET_MODE (XEXP (temp4, 0)) != BLKmode
1304 /* Even if branches are cheap, the store_flag optimization
1305 can win when the operation to be performed can be
1306 expressed directly. */
1308 /* If the previous insn sets CC0 and something else, we can't
1309 do this since we are going to delete that insn. */
1311 && ! ((temp6 = prev_nonnote_insn (insn)) != 0
1312 && GET_CODE (temp6) == INSN
1313 && (sets_cc0_p (PATTERN (temp6)) == -1
1314 || (sets_cc0_p (PATTERN (temp6)) == 1
1315 && FIND_REG_INC_NOTE (temp6, NULL_RTX))))
1319 #ifdef HAVE_conditional_move
1320 /* First try a conditional move. */
1322 enum rtx_code code = GET_CODE (temp4);
1324 rtx cond0, cond1, aval, bval;
1325 rtx target, new_insn;
1327 /* Copy the compared variables into cond0 and cond1, so that
1328 any side effects performed in or after the old comparison,
1329 will not affect our compare which will come later. */
1330 /* ??? Is it possible to just use the comparison in the jump
1331 insn? After all, we're going to delete it. We'd have
1332 to modify emit_conditional_move to take a comparison rtx
1333 instead or write a new function. */
1335 /* We want the target to be able to simplify comparisons with
1336 zero (and maybe other constants as well), so don't create
1337 pseudos for them. There's no need to either. */
1338 if (GET_CODE (XEXP (temp4, 0)) == CONST_INT
1339 || GET_CODE (XEXP (temp4, 0)) == CONST_DOUBLE)
1340 cond0 = XEXP (temp4, 0);
1342 cond0 = gen_reg_rtx (GET_MODE (XEXP (temp4, 0)));
1344 if (GET_CODE (XEXP (temp4, 1)) == CONST_INT
1345 || GET_CODE (XEXP (temp4, 1)) == CONST_DOUBLE)
1346 cond1 = XEXP (temp4, 1);
1348 cond1 = gen_reg_rtx (GET_MODE (XEXP (temp4, 1)));
1350 /* Careful about copying these values -- an IOR or what may
1351 need to do other things, like clobber flags. */
1352 /* ??? Assume for the moment that AVAL is ok. */
1357 /* We're dealing with a single_set insn with no side effects
1358 on SET_SRC. We do need to be reasonably certain that if
1359 we need to force BVAL into a register that we won't
1360 clobber the flags -- general_operand should suffice. */
1361 if (general_operand (temp2, GET_MODE (var)))
1365 bval = gen_reg_rtx (GET_MODE (var));
1366 new_insn = copy_rtx (temp);
1367 temp6 = single_set (new_insn);
1368 SET_DEST (temp6) = bval;
1369 emit_insn (PATTERN (new_insn));
1372 target = emit_conditional_move (var, code,
1373 cond0, cond1, VOIDmode,
1374 aval, bval, GET_MODE (var),
1375 (code == LTU || code == GEU
1376 || code == LEU || code == GTU));
1380 rtx seq1, seq2, last;
1383 /* Save the conditional move sequence but don't emit it
1384 yet. On some machines, like the alpha, it is possible
1385 that temp5 == insn, so next generate the sequence that
1386 saves the compared values and then emit both
1387 sequences ensuring seq1 occurs before seq2. */
1388 seq2 = get_insns ();
1391 /* "Now that we can't fail..." Famous last words.
1392 Generate the copy insns that preserve the compared
1395 emit_move_insn (cond0, XEXP (temp4, 0));
1396 if (cond1 != XEXP (temp4, 1))
1397 emit_move_insn (cond1, XEXP (temp4, 1));
1398 seq1 = get_insns ();
1401 /* Validate the sequence -- this may be some weird
1402 bit-extract-and-test instruction for which there
1403 exists no complimentary bit-extract insn. */
1405 for (last = seq1; last ; last = NEXT_INSN (last))
1406 if (recog_memoized (last) < 0)
1414 emit_insns_before (seq1, temp5);
1416 /* Insert conditional move after insn, to be sure
1417 that the jump and a possible compare won't be
1419 last = emit_insns_after (seq2, insn);
1421 /* ??? We can also delete the insn that sets X to A.
1422 Flow will do it too though. */
1424 next = NEXT_INSN (insn);
1429 reg_scan_update (seq1, NEXT_INSN (last),
1431 old_max_reg = max_reg_num ();
1443 /* That didn't work, try a store-flag insn.
1445 We further divide the cases into:
1447 1) x = a; if (...) x = b; and either A or B is zero,
1448 2) if (...) x = 0; and jumps are expensive,
1449 3) x = a; if (...) x = b; and A and B are constants where all
1450 the set bits in A are also set in B and jumps are expensive,
1451 4) x = a; if (...) x = b; and A and B non-zero, and jumps are
1453 5) if (...) x = b; if jumps are even more expensive. */
1455 if (GET_MODE_CLASS (GET_MODE (temp1)) == MODE_INT
1456 /* We will be passing this as operand into expand_and. No
1457 good if it's not valid as an operand. */
1458 && general_operand (temp2, GET_MODE (temp2))
1459 && ((GET_CODE (temp3) == CONST_INT)
1460 /* Make the latter case look like
1461 x = x; if (...) x = 0; */
1464 && temp2 == const0_rtx)
1465 || BRANCH_COST >= 3)))
1466 /* If B is zero, OK; if A is zero, can only do (1) if we
1467 can reverse the condition. See if (3) applies possibly
1468 by reversing the condition. Prefer reversing to (4) when
1469 branches are very expensive. */
1470 && (((BRANCH_COST >= 2
1471 || STORE_FLAG_VALUE == -1
1472 || (STORE_FLAG_VALUE == 1
1473 /* Check that the mask is a power of two,
1474 so that it can probably be generated
1476 && GET_CODE (temp3) == CONST_INT
1477 && exact_log2 (INTVAL (temp3)) >= 0))
1478 && (reversep = 0, temp2 == const0_rtx))
1479 || ((BRANCH_COST >= 2
1480 || STORE_FLAG_VALUE == -1
1481 || (STORE_FLAG_VALUE == 1
1482 && GET_CODE (temp2) == CONST_INT
1483 && exact_log2 (INTVAL (temp2)) >= 0))
1484 && temp3 == const0_rtx
1485 && (reversep = can_reverse_comparison_p (temp4, insn)))
1486 || (BRANCH_COST >= 2
1487 && GET_CODE (temp2) == CONST_INT
1488 && GET_CODE (temp3) == CONST_INT
1489 && ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp2)
1490 || ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp3)
1491 && (reversep = can_reverse_comparison_p (temp4,
1493 || BRANCH_COST >= 3)
1496 enum rtx_code code = GET_CODE (temp4);
1497 rtx uval, cval, var = temp1;
1501 /* If necessary, reverse the condition. */
1503 code = reverse_condition (code), uval = temp2, cval = temp3;
1505 uval = temp3, cval = temp2;
1507 /* If CVAL is non-zero, normalize to -1. Otherwise, if UVAL
1508 is the constant 1, it is best to just compute the result
1509 directly. If UVAL is constant and STORE_FLAG_VALUE
1510 includes all of its bits, it is best to compute the flag
1511 value unnormalized and `and' it with UVAL. Otherwise,
1512 normalize to -1 and `and' with UVAL. */
1513 normalizep = (cval != const0_rtx ? -1
1514 : (uval == const1_rtx ? 1
1515 : (GET_CODE (uval) == CONST_INT
1516 && (INTVAL (uval) & ~STORE_FLAG_VALUE) == 0)
1519 /* We will be putting the store-flag insn immediately in
1520 front of the comparison that was originally being done,
1521 so we know all the variables in TEMP4 will be valid.
1522 However, this might be in front of the assignment of
1523 A to VAR. If it is, it would clobber the store-flag
1524 we will be emitting.
1526 Therefore, emit into a temporary which will be copied to
1527 VAR immediately after TEMP. */
1530 target = emit_store_flag (gen_reg_rtx (GET_MODE (var)), code,
1531 XEXP (temp4, 0), XEXP (temp4, 1),
1533 (code == LTU || code == LEU
1534 || code == GEU || code == GTU),
1544 /* Put the store-flag insns in front of the first insn
1545 used to compute the condition to ensure that we
1546 use the same values of them as the current
1547 comparison. However, the remainder of the insns we
1548 generate will be placed directly in front of the
1549 jump insn, in case any of the pseudos we use
1550 are modified earlier. */
1552 emit_insns_before (seq, temp5);
1556 /* Both CVAL and UVAL are non-zero. */
1557 if (cval != const0_rtx && uval != const0_rtx)
1561 tem1 = expand_and (uval, target, NULL_RTX);
1562 if (GET_CODE (cval) == CONST_INT
1563 && GET_CODE (uval) == CONST_INT
1564 && (INTVAL (cval) & INTVAL (uval)) == INTVAL (cval))
1568 tem2 = expand_unop (GET_MODE (var), one_cmpl_optab,
1569 target, NULL_RTX, 0);
1570 tem2 = expand_and (cval, tem2,
1571 (GET_CODE (tem2) == REG
1575 /* If we usually make new pseudos, do so here. This
1576 turns out to help machines that have conditional
1578 /* ??? Conditional moves have already been handled.
1579 This may be obsolete. */
1581 if (flag_expensive_optimizations)
1584 target = expand_binop (GET_MODE (var), ior_optab,
1588 else if (normalizep != 1)
1590 /* We know that either CVAL or UVAL is zero. If
1591 UVAL is zero, negate TARGET and `and' with CVAL.
1592 Otherwise, `and' with UVAL. */
1593 if (uval == const0_rtx)
1595 target = expand_unop (GET_MODE (var), one_cmpl_optab,
1596 target, NULL_RTX, 0);
1600 target = expand_and (uval, target,
1601 (GET_CODE (target) == REG
1602 && ! preserve_subexpressions_p ()
1603 ? target : NULL_RTX));
1606 emit_move_insn (var, target);
1610 /* If INSN uses CC0, we must not separate it from the
1611 insn that sets cc0. */
1612 if (reg_mentioned_p (cc0_rtx, PATTERN (before)))
1613 before = prev_nonnote_insn (before);
1615 emit_insns_before (seq, before);
1618 next = NEXT_INSN (insn);
1623 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1624 old_max_reg = max_reg_num ();
1636 /* Simplify if (...) x = 1; else {...} if (x) ...
1637 We recognize this case scanning backwards as well.
1639 TEMP is the assignment to x;
1640 TEMP1 is the label at the head of the second if. */
1641 /* ?? This should call get_condition to find the values being
1642 compared, instead of looking for a COMPARE insn when HAVE_cc0
1643 is not defined. This would allow it to work on the m88k. */
1644 /* ?? This optimization is only safe before cse is run if HAVE_cc0
1645 is not defined and the condition is tested by a separate compare
1646 insn. This is because the code below assumes that the result
1647 of the compare dies in the following branch.
1649 Not only that, but there might be other insns between the
1650 compare and branch whose results are live. Those insns need
1653 A way to fix this is to move the insns at JUMP_LABEL (insn)
1654 to before INSN. If we are running before flow, they will
1655 be deleted if they aren't needed. But this doesn't work
1658 This is really a special-case of jump threading, anyway. The
1659 right thing to do is to replace this and jump threading with
1660 much simpler code in cse.
1662 This code has been turned off in the non-cc0 case in the
1666 else if (this_is_simplejump
1667 /* Safe to skip USE and CLOBBER insns here
1668 since they will not be deleted. */
1669 && (temp = prev_active_insn (insn))
1670 && no_labels_between_p (temp, insn)
1671 && GET_CODE (temp) == INSN
1672 && GET_CODE (PATTERN (temp)) == SET
1673 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1674 && CONSTANT_P (SET_SRC (PATTERN (temp)))
1675 && (temp1 = next_active_insn (JUMP_LABEL (insn)))
1676 /* If we find that the next value tested is `x'
1677 (TEMP1 is the insn where this happens), win. */
1678 && GET_CODE (temp1) == INSN
1679 && GET_CODE (PATTERN (temp1)) == SET
1681 /* Does temp1 `tst' the value of x? */
1682 && SET_SRC (PATTERN (temp1)) == SET_DEST (PATTERN (temp))
1683 && SET_DEST (PATTERN (temp1)) == cc0_rtx
1684 && (temp1 = next_nonnote_insn (temp1))
1686 /* Does temp1 compare the value of x against zero? */
1687 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1688 && XEXP (SET_SRC (PATTERN (temp1)), 1) == const0_rtx
1689 && (XEXP (SET_SRC (PATTERN (temp1)), 0)
1690 == SET_DEST (PATTERN (temp)))
1691 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1692 && (temp1 = find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1694 && condjump_p (temp1))
1696 /* Get the if_then_else from the condjump. */
1697 rtx choice = SET_SRC (PATTERN (temp1));
1698 if (GET_CODE (choice) == IF_THEN_ELSE)
1700 enum rtx_code code = GET_CODE (XEXP (choice, 0));
1701 rtx val = SET_SRC (PATTERN (temp));
1703 = simplify_relational_operation (code, GET_MODE (SET_DEST (PATTERN (temp))),
1707 if (cond == const_true_rtx)
1708 ultimate = XEXP (choice, 1);
1709 else if (cond == const0_rtx)
1710 ultimate = XEXP (choice, 2);
1714 if (ultimate == pc_rtx)
1715 ultimate = get_label_after (temp1);
1716 else if (ultimate && GET_CODE (ultimate) != RETURN)
1717 ultimate = XEXP (ultimate, 0);
1719 if (ultimate && JUMP_LABEL(insn) != ultimate)
1720 changed |= redirect_jump (insn, ultimate);
1726 /* @@ This needs a bit of work before it will be right.
1728 Any type of comparison can be accepted for the first and
1729 second compare. When rewriting the first jump, we must
1730 compute the what conditions can reach label3, and use the
1731 appropriate code. We can not simply reverse/swap the code
1732 of the first jump. In some cases, the second jump must be
1736 < == converts to > ==
1737 < != converts to == >
1740 If the code is written to only accept an '==' test for the second
1741 compare, then all that needs to be done is to swap the condition
1742 of the first branch.
1744 It is questionable whether we want this optimization anyways,
1745 since if the user wrote code like this because he/she knew that
1746 the jump to label1 is taken most of the time, then rewriting
1747 this gives slower code. */
1748 /* @@ This should call get_condition to find the values being
1749 compared, instead of looking for a COMPARE insn when HAVE_cc0
1750 is not defined. This would allow it to work on the m88k. */
1751 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1752 is not defined and the condition is tested by a separate compare
1753 insn. This is because the code below assumes that the result
1754 of the compare dies in the following branch. */
1756 /* Simplify test a ~= b
1770 where ~= is an inequality, e.g. >, and ~~= is the swapped
1773 We recognize this case scanning backwards.
1775 TEMP is the conditional jump to `label2';
1776 TEMP1 is the test for `a == b';
1777 TEMP2 is the conditional jump to `label1';
1778 TEMP3 is the test for `a ~= b'. */
1779 else if (this_is_simplejump
1780 && (temp = prev_active_insn (insn))
1781 && no_labels_between_p (temp, insn)
1782 && condjump_p (temp)
1783 && (temp1 = prev_active_insn (temp))
1784 && no_labels_between_p (temp1, temp)
1785 && GET_CODE (temp1) == INSN
1786 && GET_CODE (PATTERN (temp1)) == SET
1788 && sets_cc0_p (PATTERN (temp1)) == 1
1790 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1791 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1792 && (temp == find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1794 && (temp2 = prev_active_insn (temp1))
1795 && no_labels_between_p (temp2, temp1)
1796 && condjump_p (temp2)
1797 && JUMP_LABEL (temp2) == next_nonnote_insn (NEXT_INSN (insn))
1798 && (temp3 = prev_active_insn (temp2))
1799 && no_labels_between_p (temp3, temp2)
1800 && GET_CODE (PATTERN (temp3)) == SET
1801 && rtx_equal_p (SET_DEST (PATTERN (temp3)),
1802 SET_DEST (PATTERN (temp1)))
1803 && rtx_equal_p (SET_SRC (PATTERN (temp1)),
1804 SET_SRC (PATTERN (temp3)))
1805 && ! inequality_comparisons_p (PATTERN (temp))
1806 && inequality_comparisons_p (PATTERN (temp2)))
1808 rtx fallthrough_label = JUMP_LABEL (temp2);
1810 ++LABEL_NUSES (fallthrough_label);
1811 if (swap_jump (temp2, JUMP_LABEL (insn)))
1817 if (--LABEL_NUSES (fallthrough_label) == 0)
1818 delete_insn (fallthrough_label);
1821 /* Simplify if (...) {... x = 1;} if (x) ...
1823 We recognize this case backwards.
1825 TEMP is the test of `x';
1826 TEMP1 is the assignment to `x' at the end of the
1827 previous statement. */
1828 /* @@ This should call get_condition to find the values being
1829 compared, instead of looking for a COMPARE insn when HAVE_cc0
1830 is not defined. This would allow it to work on the m88k. */
1831 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1832 is not defined and the condition is tested by a separate compare
1833 insn. This is because the code below assumes that the result
1834 of the compare dies in the following branch. */
1836 /* ??? This has to be turned off. The problem is that the
1837 unconditional jump might indirectly end up branching to the
1838 label between TEMP1 and TEMP. We can't detect this, in general,
1839 since it may become a jump to there after further optimizations.
1840 If that jump is done, it will be deleted, so we will retry
1841 this optimization in the next pass, thus an infinite loop.
1843 The present code prevents this by putting the jump after the
1844 label, but this is not logically correct. */
1846 else if (this_is_condjump
1847 /* Safe to skip USE and CLOBBER insns here
1848 since they will not be deleted. */
1849 && (temp = prev_active_insn (insn))
1850 && no_labels_between_p (temp, insn)
1851 && GET_CODE (temp) == INSN
1852 && GET_CODE (PATTERN (temp)) == SET
1854 && sets_cc0_p (PATTERN (temp)) == 1
1855 && GET_CODE (SET_SRC (PATTERN (temp))) == REG
1857 /* Temp must be a compare insn, we can not accept a register
1858 to register move here, since it may not be simply a
1860 && GET_CODE (SET_SRC (PATTERN (temp))) == COMPARE
1861 && XEXP (SET_SRC (PATTERN (temp)), 1) == const0_rtx
1862 && GET_CODE (XEXP (SET_SRC (PATTERN (temp)), 0)) == REG
1863 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1864 && insn == find_next_ref (SET_DEST (PATTERN (temp)), temp)
1866 /* May skip USE or CLOBBER insns here
1867 for checking for opportunity, since we
1868 take care of them later. */
1869 && (temp1 = prev_active_insn (temp))
1870 && GET_CODE (temp1) == INSN
1871 && GET_CODE (PATTERN (temp1)) == SET
1873 && SET_SRC (PATTERN (temp)) == SET_DEST (PATTERN (temp1))
1875 && (XEXP (SET_SRC (PATTERN (temp)), 0)
1876 == SET_DEST (PATTERN (temp1)))
1878 && CONSTANT_P (SET_SRC (PATTERN (temp1)))
1879 /* If this isn't true, cse will do the job. */
1880 && ! no_labels_between_p (temp1, temp))
1882 /* Get the if_then_else from the condjump. */
1883 rtx choice = SET_SRC (PATTERN (insn));
1884 if (GET_CODE (choice) == IF_THEN_ELSE
1885 && (GET_CODE (XEXP (choice, 0)) == EQ
1886 || GET_CODE (XEXP (choice, 0)) == NE))
1888 int want_nonzero = (GET_CODE (XEXP (choice, 0)) == NE);
1893 /* Get the place that condjump will jump to
1894 if it is reached from here. */
1895 if ((SET_SRC (PATTERN (temp1)) != const0_rtx)
1897 ultimate = XEXP (choice, 1);
1899 ultimate = XEXP (choice, 2);
1900 /* Get it as a CODE_LABEL. */
1901 if (ultimate == pc_rtx)
1902 ultimate = get_label_after (insn);
1904 /* Get the label out of the LABEL_REF. */
1905 ultimate = XEXP (ultimate, 0);
1907 /* Insert the jump immediately before TEMP, specifically
1908 after the label that is between TEMP1 and TEMP. */
1909 last_insn = PREV_INSN (temp);
1911 /* If we would be branching to the next insn, the jump
1912 would immediately be deleted and the re-inserted in
1913 a subsequent pass over the code. So don't do anything
1915 if (next_active_insn (last_insn)
1916 != next_active_insn (ultimate))
1918 emit_barrier_after (last_insn);
1919 p = emit_jump_insn_after (gen_jump (ultimate),
1921 JUMP_LABEL (p) = ultimate;
1922 ++LABEL_NUSES (ultimate);
1923 if (INSN_UID (ultimate) < max_jump_chain
1924 && INSN_CODE (p) < max_jump_chain)
1926 jump_chain[INSN_UID (p)]
1927 = jump_chain[INSN_UID (ultimate)];
1928 jump_chain[INSN_UID (ultimate)] = p;
1937 /* Detect a conditional jump jumping over an unconditional trap. */
1939 && this_is_condjump && ! this_is_simplejump
1940 && reallabelprev != 0
1941 && GET_CODE (reallabelprev) == INSN
1942 && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
1943 && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
1944 && prev_active_insn (reallabelprev) == insn
1945 && no_labels_between_p (insn, reallabelprev)
1946 && (temp2 = get_condition (insn, &temp4))
1947 && can_reverse_comparison_p (temp2, insn))
1949 rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
1950 XEXP (temp2, 0), XEXP (temp2, 1),
1951 TRAP_CODE (PATTERN (reallabelprev)));
1955 emit_insn_before (new, temp4);
1956 delete_insn (reallabelprev);
1962 /* Detect a jump jumping to an unconditional trap. */
1963 else if (HAVE_trap && this_is_condjump
1964 && (temp = next_active_insn (JUMP_LABEL (insn)))
1965 && GET_CODE (temp) == INSN
1966 && GET_CODE (PATTERN (temp)) == TRAP_IF
1967 && (this_is_simplejump
1968 || (temp2 = get_condition (insn, &temp4))))
1970 rtx tc = TRAP_CONDITION (PATTERN (temp));
1972 if (tc == const_true_rtx
1973 || (! this_is_simplejump && rtx_equal_p (temp2, tc)))
1976 /* Replace an unconditional jump to a trap with a trap. */
1977 if (this_is_simplejump)
1979 emit_barrier_after (emit_insn_before (gen_trap (), insn));
1984 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
1986 TRAP_CODE (PATTERN (temp)));
1989 emit_insn_before (new, temp4);
1995 /* If the trap condition and jump condition are mutually
1996 exclusive, redirect the jump to the following insn. */
1997 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
1998 && ! this_is_simplejump
1999 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
2000 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
2001 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
2002 && redirect_jump (insn, get_label_after (temp)))
2011 /* Now that the jump has been tensioned,
2012 try cross jumping: check for identical code
2013 before the jump and before its target label. */
2015 /* First, cross jumping of conditional jumps: */
2017 if (cross_jump && condjump_p (insn))
2019 rtx newjpos, newlpos;
2020 rtx x = prev_real_insn (JUMP_LABEL (insn));
2022 /* A conditional jump may be crossjumped
2023 only if the place it jumps to follows
2024 an opposing jump that comes back here. */
2026 if (x != 0 && ! jump_back_p (x, insn))
2027 /* We have no opposing jump;
2028 cannot cross jump this insn. */
2032 /* TARGET is nonzero if it is ok to cross jump
2033 to code before TARGET. If so, see if matches. */
2035 find_cross_jump (insn, x, 2,
2036 &newjpos, &newlpos);
2040 do_cross_jump (insn, newjpos, newlpos);
2041 /* Make the old conditional jump
2042 into an unconditional one. */
2043 SET_SRC (PATTERN (insn))
2044 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
2045 INSN_CODE (insn) = -1;
2046 emit_barrier_after (insn);
2047 /* Add to jump_chain unless this is a new label
2048 whose UID is too large. */
2049 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
2051 jump_chain[INSN_UID (insn)]
2052 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2053 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2060 /* Cross jumping of unconditional jumps:
2061 a few differences. */
2063 if (cross_jump && simplejump_p (insn))
2065 rtx newjpos, newlpos;
2070 /* TARGET is nonzero if it is ok to cross jump
2071 to code before TARGET. If so, see if matches. */
2072 find_cross_jump (insn, JUMP_LABEL (insn), 1,
2073 &newjpos, &newlpos);
2075 /* If cannot cross jump to code before the label,
2076 see if we can cross jump to another jump to
2078 /* Try each other jump to this label. */
2079 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
2080 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2081 target != 0 && newjpos == 0;
2082 target = jump_chain[INSN_UID (target)])
2084 && JUMP_LABEL (target) == JUMP_LABEL (insn)
2085 /* Ignore TARGET if it's deleted. */
2086 && ! INSN_DELETED_P (target))
2087 find_cross_jump (insn, target, 2,
2088 &newjpos, &newlpos);
2092 do_cross_jump (insn, newjpos, newlpos);
2098 /* This code was dead in the previous jump.c! */
2099 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
2101 /* Return insns all "jump to the same place"
2102 so we can cross-jump between any two of them. */
2104 rtx newjpos, newlpos, target;
2108 /* If cannot cross jump to code before the label,
2109 see if we can cross jump to another jump to
2111 /* Try each other jump to this label. */
2112 for (target = jump_chain[0];
2113 target != 0 && newjpos == 0;
2114 target = jump_chain[INSN_UID (target)])
2116 && ! INSN_DELETED_P (target)
2117 && GET_CODE (PATTERN (target)) == RETURN)
2118 find_cross_jump (insn, target, 2,
2119 &newjpos, &newlpos);
2123 do_cross_jump (insn, newjpos, newlpos);
2134 /* Delete extraneous line number notes.
2135 Note that two consecutive notes for different lines are not really
2136 extraneous. There should be some indication where that line belonged,
2137 even if it became empty. */
2142 for (insn = f; insn; insn = NEXT_INSN (insn))
2143 if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
2145 /* Delete this note if it is identical to previous note. */
2147 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
2148 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
2158 /* CAN_REACH_END is persistent for each function. Once set it should
2159 not be cleared. This is especially true for the case where we
2160 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
2161 the front-end before compiling each function. */
2162 if (! minimal && calculate_can_reach_end (last_insn, optimize != 0))
2171 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
2172 notes whose labels don't occur in the insn any more. Returns the
2173 largest INSN_UID found. */
2178 int largest_uid = 0;
2181 for (insn = f; insn; insn = NEXT_INSN (insn))
2183 if (GET_CODE (insn) == CODE_LABEL)
2184 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
2185 else if (GET_CODE (insn) == JUMP_INSN)
2186 JUMP_LABEL (insn) = 0;
2187 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2191 for (note = REG_NOTES (insn); note; note = next)
2193 next = XEXP (note, 1);
2194 if (REG_NOTE_KIND (note) == REG_LABEL
2195 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
2196 remove_note (insn, note);
2199 if (INSN_UID (insn) > largest_uid)
2200 largest_uid = INSN_UID (insn);
2206 /* Delete insns following barriers, up to next label.
2208 Also delete no-op jumps created by gcse. */
2211 delete_barrier_successors (f)
2216 for (insn = f; insn;)
2218 if (GET_CODE (insn) == BARRIER)
2220 insn = NEXT_INSN (insn);
2222 never_reached_warning (insn);
2224 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
2226 if (GET_CODE (insn) == NOTE
2227 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2228 insn = NEXT_INSN (insn);
2230 insn = delete_insn (insn);
2232 /* INSN is now the code_label. */
2235 /* Also remove (set (pc) (pc)) insns which can be created by
2236 gcse. We eliminate such insns now to avoid having them
2237 cause problems later. */
2238 else if (GET_CODE (insn) == JUMP_INSN
2239 && GET_CODE (PATTERN (insn)) == SET
2240 && SET_SRC (PATTERN (insn)) == pc_rtx
2241 && SET_DEST (PATTERN (insn)) == pc_rtx)
2242 insn = delete_insn (insn);
2245 insn = NEXT_INSN (insn);
2249 /* Mark the label each jump jumps to.
2250 Combine consecutive labels, and count uses of labels.
2252 For each label, make a chain (using `jump_chain')
2253 of all the *unconditional* jumps that jump to it;
2254 also make a chain of all returns.
2256 CROSS_JUMP indicates whether we are doing cross jumping
2257 and if we are whether we will be paying attention to
2258 death notes or not. */
2261 mark_all_labels (f, cross_jump)
2267 for (insn = f; insn; insn = NEXT_INSN (insn))
2268 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
2270 if (GET_CODE (insn) == CALL_INSN
2271 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
2273 mark_all_labels (XEXP (PATTERN (insn), 0), cross_jump);
2274 mark_all_labels (XEXP (PATTERN (insn), 1), cross_jump);
2275 mark_all_labels (XEXP (PATTERN (insn), 2), cross_jump);
2279 mark_jump_label (PATTERN (insn), insn, cross_jump, 0);
2280 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
2282 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
2284 jump_chain[INSN_UID (insn)]
2285 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2286 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2288 if (GET_CODE (PATTERN (insn)) == RETURN)
2290 jump_chain[INSN_UID (insn)] = jump_chain[0];
2291 jump_chain[0] = insn;
2297 /* Delete all labels already not referenced.
2298 Also find and return the last insn. */
2301 delete_unreferenced_labels (f)
2304 rtx final = NULL_RTX;
2307 for (insn = f; insn; )
2309 if (GET_CODE (insn) == CODE_LABEL
2310 && LABEL_NUSES (insn) == 0
2311 && LABEL_ALTERNATE_NAME (insn) == NULL)
2312 insn = delete_insn (insn);
2316 insn = NEXT_INSN (insn);
2323 /* Delete various simple forms of moves which have no necessary
2327 delete_noop_moves (f)
2332 for (insn = f; insn; )
2334 next = NEXT_INSN (insn);
2336 if (GET_CODE (insn) == INSN)
2338 register rtx body = PATTERN (insn);
2340 /* Detect and delete no-op move instructions
2341 resulting from not allocating a parameter in a register. */
2343 if (GET_CODE (body) == SET
2344 && (SET_DEST (body) == SET_SRC (body)
2345 || (GET_CODE (SET_DEST (body)) == MEM
2346 && GET_CODE (SET_SRC (body)) == MEM
2347 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
2348 && ! (GET_CODE (SET_DEST (body)) == MEM
2349 && MEM_VOLATILE_P (SET_DEST (body)))
2350 && ! (GET_CODE (SET_SRC (body)) == MEM
2351 && MEM_VOLATILE_P (SET_SRC (body))))
2352 delete_computation (insn);
2354 /* Detect and ignore no-op move instructions
2355 resulting from smart or fortuitous register allocation. */
2357 else if (GET_CODE (body) == SET)
2359 int sreg = true_regnum (SET_SRC (body));
2360 int dreg = true_regnum (SET_DEST (body));
2362 if (sreg == dreg && sreg >= 0)
2364 else if (sreg >= 0 && dreg >= 0)
2367 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
2368 sreg, NULL_PTR, dreg,
2369 GET_MODE (SET_SRC (body)));
2372 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
2374 /* DREG may have been the target of a REG_DEAD note in
2375 the insn which makes INSN redundant. If so, reorg
2376 would still think it is dead. So search for such a
2377 note and delete it if we find it. */
2378 if (! find_regno_note (insn, REG_UNUSED, dreg))
2379 for (trial = prev_nonnote_insn (insn);
2380 trial && GET_CODE (trial) != CODE_LABEL;
2381 trial = prev_nonnote_insn (trial))
2382 if (find_regno_note (trial, REG_DEAD, dreg))
2384 remove_death (dreg, trial);
2388 /* Deleting insn could lose a death-note for SREG. */
2389 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
2391 /* Change this into a USE so that we won't emit
2392 code for it, but still can keep the note. */
2394 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
2395 INSN_CODE (insn) = -1;
2396 /* Remove all reg notes but the REG_DEAD one. */
2397 REG_NOTES (insn) = trial;
2398 XEXP (trial, 1) = NULL_RTX;
2404 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
2405 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
2407 GET_MODE (SET_DEST (body))))
2409 /* This handles the case where we have two consecutive
2410 assignments of the same constant to pseudos that didn't
2411 get a hard reg. Each SET from the constant will be
2412 converted into a SET of the spill register and an
2413 output reload will be made following it. This produces
2414 two loads of the same constant into the same spill
2419 /* Look back for a death note for the first reg.
2420 If there is one, it is no longer accurate. */
2421 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
2423 if ((GET_CODE (in_insn) == INSN
2424 || GET_CODE (in_insn) == JUMP_INSN)
2425 && find_regno_note (in_insn, REG_DEAD, dreg))
2427 remove_death (dreg, in_insn);
2430 in_insn = PREV_INSN (in_insn);
2433 /* Delete the second load of the value. */
2437 else if (GET_CODE (body) == PARALLEL)
2439 /* If each part is a set between two identical registers or
2440 a USE or CLOBBER, delete the insn. */
2444 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
2446 tem = XVECEXP (body, 0, i);
2447 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
2450 if (GET_CODE (tem) != SET
2451 || (sreg = true_regnum (SET_SRC (tem))) < 0
2452 || (dreg = true_regnum (SET_DEST (tem))) < 0
2460 /* Also delete insns to store bit fields if they are no-ops. */
2461 /* Not worth the hair to detect this in the big-endian case. */
2462 else if (! BYTES_BIG_ENDIAN
2463 && GET_CODE (body) == SET
2464 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
2465 && XEXP (SET_DEST (body), 2) == const0_rtx
2466 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
2467 && ! (GET_CODE (SET_SRC (body)) == MEM
2468 && MEM_VOLATILE_P (SET_SRC (body))))
2475 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
2476 If so indicate that this function can drop off the end by returning
2479 CHECK_DELETED indicates whether we must check if the note being
2480 searched for has the deleted flag set.
2482 DELETE_FINAL_NOTE indicates whether we should delete the note
2486 calculate_can_reach_end (last, delete_final_note)
2488 int delete_final_note;
2493 while (insn != NULL_RTX)
2497 /* One label can follow the end-note: the return label. */
2498 if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
2500 /* Ordinary insns can follow it if returning a structure. */
2501 else if (GET_CODE (insn) == INSN)
2503 /* If machine uses explicit RETURN insns, no epilogue,
2504 then one of them follows the note. */
2505 else if (GET_CODE (insn) == JUMP_INSN
2506 && GET_CODE (PATTERN (insn)) == RETURN)
2508 /* A barrier can follow the return insn. */
2509 else if (GET_CODE (insn) == BARRIER)
2511 /* Other kinds of notes can follow also. */
2512 else if (GET_CODE (insn) == NOTE
2513 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2519 insn = PREV_INSN (insn);
2522 /* See if we backed up to the appropriate type of note. */
2523 if (insn != NULL_RTX
2524 && GET_CODE (insn) == NOTE
2525 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END)
2527 if (delete_final_note)
2535 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
2536 jump. Assume that this unconditional jump is to the exit test code. If
2537 the code is sufficiently simple, make a copy of it before INSN,
2538 followed by a jump to the exit of the loop. Then delete the unconditional
2541 Return 1 if we made the change, else 0.
2543 This is only safe immediately after a regscan pass because it uses the
2544 values of regno_first_uid and regno_last_uid. */
2547 duplicate_loop_exit_test (loop_start)
2550 rtx insn, set, reg, p, link;
2551 rtx copy = 0, first_copy = 0;
2553 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
2555 int max_reg = max_reg_num ();
2558 /* Scan the exit code. We do not perform this optimization if any insn:
2562 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
2563 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
2564 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
2567 We also do not do this if we find an insn with ASM_OPERANDS. While
2568 this restriction should not be necessary, copying an insn with
2569 ASM_OPERANDS can confuse asm_noperands in some cases.
2571 Also, don't do this if the exit code is more than 20 insns. */
2573 for (insn = exitcode;
2575 && ! (GET_CODE (insn) == NOTE
2576 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
2577 insn = NEXT_INSN (insn))
2579 switch (GET_CODE (insn))
2585 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
2586 a jump immediately after the loop start that branches outside
2587 the loop but within an outer loop, near the exit test.
2588 If we copied this exit test and created a phony
2589 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
2590 before the exit test look like these could be safely moved
2591 out of the loop even if they actually may be never executed.
2592 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
2594 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
2595 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
2599 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2600 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2601 /* If we were to duplicate this code, we would not move
2602 the BLOCK notes, and so debugging the moved code would
2603 be difficult. Thus, we only move the code with -O2 or
2610 /* The code below would grossly mishandle REG_WAS_0 notes,
2611 so get rid of them here. */
2612 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
2613 remove_note (insn, p);
2614 if (++num_insns > 20
2615 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
2616 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
2624 /* Unless INSN is zero, we can do the optimization. */
2630 /* See if any insn sets a register only used in the loop exit code and
2631 not a user variable. If so, replace it with a new register. */
2632 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2633 if (GET_CODE (insn) == INSN
2634 && (set = single_set (insn)) != 0
2635 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
2636 || (GET_CODE (reg) == SUBREG
2637 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
2638 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
2639 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
2641 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
2642 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
2647 /* We can do the replacement. Allocate reg_map if this is the
2648 first replacement we found. */
2650 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
2652 REG_LOOP_TEST_P (reg) = 1;
2654 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
2658 /* Now copy each insn. */
2659 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2661 switch (GET_CODE (insn))
2664 copy = emit_barrier_before (loop_start);
2667 /* Only copy line-number notes. */
2668 if (NOTE_LINE_NUMBER (insn) >= 0)
2670 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
2671 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
2676 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
2678 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2680 mark_jump_label (PATTERN (copy), copy, 0, 0);
2682 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
2684 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2685 if (REG_NOTE_KIND (link) != REG_LABEL)
2687 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
2690 if (reg_map && REG_NOTES (copy))
2691 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2695 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)), loop_start);
2697 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2698 mark_jump_label (PATTERN (copy), copy, 0, 0);
2699 if (REG_NOTES (insn))
2701 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
2703 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2706 /* If this is a simple jump, add it to the jump chain. */
2708 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
2709 && simplejump_p (copy))
2711 jump_chain[INSN_UID (copy)]
2712 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2713 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2721 /* Record the first insn we copied. We need it so that we can
2722 scan the copied insns for new pseudo registers. */
2727 /* Now clean up by emitting a jump to the end label and deleting the jump
2728 at the start of the loop. */
2729 if (! copy || GET_CODE (copy) != BARRIER)
2731 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
2734 /* Record the first insn we copied. We need it so that we can
2735 scan the copied insns for new pseudo registers. This may not
2736 be strictly necessary since we should have copied at least one
2737 insn above. But I am going to be safe. */
2741 mark_jump_label (PATTERN (copy), copy, 0, 0);
2742 if (INSN_UID (copy) < max_jump_chain
2743 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
2745 jump_chain[INSN_UID (copy)]
2746 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2747 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2749 emit_barrier_before (loop_start);
2752 /* Now scan from the first insn we copied to the last insn we copied
2753 (copy) for new pseudo registers. Do this after the code to jump to
2754 the end label since that might create a new pseudo too. */
2755 reg_scan_update (first_copy, copy, max_reg);
2757 /* Mark the exit code as the virtual top of the converted loop. */
2758 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
2760 delete_insn (next_nonnote_insn (loop_start));
2769 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
2770 loop-end notes between START and END out before START. Assume that
2771 END is not such a note. START may be such a note. Returns the value
2772 of the new starting insn, which may be different if the original start
2776 squeeze_notes (start, end)
2782 for (insn = start; insn != end; insn = next)
2784 next = NEXT_INSN (insn);
2785 if (GET_CODE (insn) == NOTE
2786 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
2787 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2788 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
2789 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
2790 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
2791 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
2797 rtx prev = PREV_INSN (insn);
2798 PREV_INSN (insn) = PREV_INSN (start);
2799 NEXT_INSN (insn) = start;
2800 NEXT_INSN (PREV_INSN (insn)) = insn;
2801 PREV_INSN (NEXT_INSN (insn)) = insn;
2802 NEXT_INSN (prev) = next;
2803 PREV_INSN (next) = prev;
2811 /* Compare the instructions before insn E1 with those before E2
2812 to find an opportunity for cross jumping.
2813 (This means detecting identical sequences of insns followed by
2814 jumps to the same place, or followed by a label and a jump
2815 to that label, and replacing one with a jump to the other.)
2817 Assume E1 is a jump that jumps to label E2
2818 (that is not always true but it might as well be).
2819 Find the longest possible equivalent sequences
2820 and store the first insns of those sequences into *F1 and *F2.
2821 Store zero there if no equivalent preceding instructions are found.
2823 We give up if we find a label in stream 1.
2824 Actually we could transfer that label into stream 2. */
2827 find_cross_jump (e1, e2, minimum, f1, f2)
2832 register rtx i1 = e1, i2 = e2;
2833 register rtx p1, p2;
2836 rtx last1 = 0, last2 = 0;
2837 rtx afterlast1 = 0, afterlast2 = 0;
2844 i1 = prev_nonnote_insn (i1);
2846 i2 = PREV_INSN (i2);
2847 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
2848 i2 = PREV_INSN (i2);
2853 /* Don't allow the range of insns preceding E1 or E2
2854 to include the other (E2 or E1). */
2855 if (i2 == e1 || i1 == e2)
2858 /* If we will get to this code by jumping, those jumps will be
2859 tensioned to go directly to the new label (before I2),
2860 so this cross-jumping won't cost extra. So reduce the minimum. */
2861 if (GET_CODE (i1) == CODE_LABEL)
2867 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
2870 /* Avoid moving insns across EH regions if either of the insns
2873 && (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
2874 && !in_same_eh_region (i1, i2))
2880 /* If this is a CALL_INSN, compare register usage information.
2881 If we don't check this on stack register machines, the two
2882 CALL_INSNs might be merged leaving reg-stack.c with mismatching
2883 numbers of stack registers in the same basic block.
2884 If we don't check this on machines with delay slots, a delay slot may
2885 be filled that clobbers a parameter expected by the subroutine.
2887 ??? We take the simple route for now and assume that if they're
2888 equal, they were constructed identically. */
2890 if (GET_CODE (i1) == CALL_INSN
2891 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
2892 CALL_INSN_FUNCTION_USAGE (i2)))
2896 /* If cross_jump_death_matters is not 0, the insn's mode
2897 indicates whether or not the insn contains any stack-like
2900 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
2902 /* If register stack conversion has already been done, then
2903 death notes must also be compared before it is certain that
2904 the two instruction streams match. */
2907 HARD_REG_SET i1_regset, i2_regset;
2909 CLEAR_HARD_REG_SET (i1_regset);
2910 CLEAR_HARD_REG_SET (i2_regset);
2912 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
2913 if (REG_NOTE_KIND (note) == REG_DEAD
2914 && STACK_REG_P (XEXP (note, 0)))
2915 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
2917 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
2918 if (REG_NOTE_KIND (note) == REG_DEAD
2919 && STACK_REG_P (XEXP (note, 0)))
2920 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
2922 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
2931 /* Don't allow old-style asm or volatile extended asms to be accepted
2932 for cross jumping purposes. It is conceptually correct to allow
2933 them, since cross-jumping preserves the dynamic instruction order
2934 even though it is changing the static instruction order. However,
2935 if an asm is being used to emit an assembler pseudo-op, such as
2936 the MIPS `.set reorder' pseudo-op, then the static instruction order
2937 matters and it must be preserved. */
2938 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
2939 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
2940 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
2943 if (lose || GET_CODE (p1) != GET_CODE (p2)
2944 || ! rtx_renumbered_equal_p (p1, p2))
2946 /* The following code helps take care of G++ cleanups. */
2950 if (!lose && GET_CODE (p1) == GET_CODE (p2)
2951 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
2952 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
2953 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
2954 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
2955 /* If the equivalences are not to a constant, they may
2956 reference pseudos that no longer exist, so we can't
2958 && CONSTANT_P (XEXP (equiv1, 0))
2959 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
2961 rtx s1 = single_set (i1);
2962 rtx s2 = single_set (i2);
2963 if (s1 != 0 && s2 != 0
2964 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
2966 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
2967 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
2968 if (! rtx_renumbered_equal_p (p1, p2))
2970 else if (apply_change_group ())
2975 /* Insns fail to match; cross jumping is limited to the following
2979 /* Don't allow the insn after a compare to be shared by
2980 cross-jumping unless the compare is also shared.
2981 Here, if either of these non-matching insns is a compare,
2982 exclude the following insn from possible cross-jumping. */
2983 if (sets_cc0_p (p1) || sets_cc0_p (p2))
2984 last1 = afterlast1, last2 = afterlast2, ++minimum;
2987 /* If cross-jumping here will feed a jump-around-jump
2988 optimization, this jump won't cost extra, so reduce
2990 if (GET_CODE (i1) == JUMP_INSN
2992 && prev_real_insn (JUMP_LABEL (i1)) == e1)
2998 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
3000 /* Ok, this insn is potentially includable in a cross-jump here. */
3001 afterlast1 = last1, afterlast2 = last2;
3002 last1 = i1, last2 = i2, --minimum;
3006 if (minimum <= 0 && last1 != 0 && last1 != e1)
3007 *f1 = last1, *f2 = last2;
3011 do_cross_jump (insn, newjpos, newlpos)
3012 rtx insn, newjpos, newlpos;
3014 /* Find an existing label at this point
3015 or make a new one if there is none. */
3016 register rtx label = get_label_before (newlpos);
3018 /* Make the same jump insn jump to the new point. */
3019 if (GET_CODE (PATTERN (insn)) == RETURN)
3021 /* Remove from jump chain of returns. */
3022 delete_from_jump_chain (insn);
3023 /* Change the insn. */
3024 PATTERN (insn) = gen_jump (label);
3025 INSN_CODE (insn) = -1;
3026 JUMP_LABEL (insn) = label;
3027 LABEL_NUSES (label)++;
3028 /* Add to new the jump chain. */
3029 if (INSN_UID (label) < max_jump_chain
3030 && INSN_UID (insn) < max_jump_chain)
3032 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
3033 jump_chain[INSN_UID (label)] = insn;
3037 redirect_jump (insn, label);
3039 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
3040 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
3041 the NEWJPOS stream. */
3043 while (newjpos != insn)
3047 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
3048 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
3049 || REG_NOTE_KIND (lnote) == REG_EQUIV)
3050 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
3051 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
3052 remove_note (newlpos, lnote);
3054 delete_insn (newjpos);
3055 newjpos = next_real_insn (newjpos);
3056 newlpos = next_real_insn (newlpos);
3060 /* Return the label before INSN, or put a new label there. */
3063 get_label_before (insn)
3068 /* Find an existing label at this point
3069 or make a new one if there is none. */
3070 label = prev_nonnote_insn (insn);
3072 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3074 rtx prev = PREV_INSN (insn);
3076 label = gen_label_rtx ();
3077 emit_label_after (label, prev);
3078 LABEL_NUSES (label) = 0;
3083 /* Return the label after INSN, or put a new label there. */
3086 get_label_after (insn)
3091 /* Find an existing label at this point
3092 or make a new one if there is none. */
3093 label = next_nonnote_insn (insn);
3095 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3097 label = gen_label_rtx ();
3098 emit_label_after (label, insn);
3099 LABEL_NUSES (label) = 0;
3104 /* Return 1 if INSN is a jump that jumps to right after TARGET
3105 only on the condition that TARGET itself would drop through.
3106 Assumes that TARGET is a conditional jump. */
3109 jump_back_p (insn, target)
3113 enum rtx_code codei, codet;
3115 if (simplejump_p (insn) || ! condjump_p (insn)
3116 || simplejump_p (target)
3117 || target != prev_real_insn (JUMP_LABEL (insn)))
3120 cinsn = XEXP (SET_SRC (PATTERN (insn)), 0);
3121 ctarget = XEXP (SET_SRC (PATTERN (target)), 0);
3123 codei = GET_CODE (cinsn);
3124 codet = GET_CODE (ctarget);
3126 if (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx)
3128 if (! can_reverse_comparison_p (cinsn, insn))
3130 codei = reverse_condition (codei);
3133 if (XEXP (SET_SRC (PATTERN (target)), 2) == pc_rtx)
3135 if (! can_reverse_comparison_p (ctarget, target))
3137 codet = reverse_condition (codet);
3140 return (codei == codet
3141 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
3142 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
3145 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
3146 return non-zero if it is safe to reverse this comparison. It is if our
3147 floating-point is not IEEE, if this is an NE or EQ comparison, or if
3148 this is known to be an integer comparison. */
3151 can_reverse_comparison_p (comparison, insn)
3157 /* If this is not actually a comparison, we can't reverse it. */
3158 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
3161 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3162 /* If this is an NE comparison, it is safe to reverse it to an EQ
3163 comparison and vice versa, even for floating point. If no operands
3164 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
3165 always false and NE is always true, so the reversal is also valid. */
3167 || GET_CODE (comparison) == NE
3168 || GET_CODE (comparison) == EQ)
3171 arg0 = XEXP (comparison, 0);
3173 /* Make sure ARG0 is one of the actual objects being compared. If we
3174 can't do this, we can't be sure the comparison can be reversed.
3176 Handle cc0 and a MODE_CC register. */
3177 if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
3183 rtx prev = prev_nonnote_insn (insn);
3186 /* First see if the condition code mode alone if enough to say we can
3187 reverse the condition. If not, then search backwards for a set of
3188 ARG0. We do not need to check for an insn clobbering it since valid
3189 code will contain set a set with no intervening clobber. But
3190 stop when we reach a label. */
3191 #ifdef REVERSIBLE_CC_MODE
3192 if (GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC
3193 && REVERSIBLE_CC_MODE (GET_MODE (arg0)))
3197 for (prev = prev_nonnote_insn (insn);
3198 prev != 0 && GET_CODE (prev) != CODE_LABEL;
3199 prev = prev_nonnote_insn (prev))
3200 if ((set = single_set (prev)) != 0
3201 && rtx_equal_p (SET_DEST (set), arg0))
3203 arg0 = SET_SRC (set);
3205 if (GET_CODE (arg0) == COMPARE)
3206 arg0 = XEXP (arg0, 0);
3211 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
3212 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
3213 return (GET_CODE (arg0) == CONST_INT
3214 || (GET_MODE (arg0) != VOIDmode
3215 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
3216 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
3219 /* Given an rtx-code for a comparison, return the code for the negated
3220 comparison. If no such code exists, return UNKNOWN.
3222 WATCH OUT! reverse_condition is not safe to use on a jump that might
3223 be acting on the results of an IEEE floating point comparison, because
3224 of the special treatment of non-signaling nans in comparisons.
3225 Use can_reverse_comparison_p to be sure. */
3228 reverse_condition (code)
3271 /* Similar, but we're allowed to generate unordered comparisons, which
3272 makes it safe for IEEE floating-point. Of course, we have to recognize
3273 that the target will support them too... */
3276 reverse_condition_maybe_unordered (code)
3279 /* Non-IEEE formats don't have unordered conditions. */
3280 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
3281 return reverse_condition (code);
3327 /* Similar, but return the code when two operands of a comparison are swapped.
3328 This IS safe for IEEE floating-point. */
3331 swap_condition (code)
3374 /* Given a comparison CODE, return the corresponding unsigned comparison.
3375 If CODE is an equality comparison or already an unsigned comparison,
3376 CODE is returned. */
3379 unsigned_condition (code)
3406 /* Similarly, return the signed version of a comparison. */
3409 signed_condition (code)
3436 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
3437 truth of CODE1 implies the truth of CODE2. */
3440 comparison_dominates_p (code1, code2)
3441 enum rtx_code code1, code2;
3449 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
3450 || code2 == ORDERED)
3455 if (code2 == LE || code2 == NE || code2 == ORDERED)
3460 if (code2 == GE || code2 == NE || code2 == ORDERED)
3466 if (code2 == ORDERED)
3471 if (code2 == NE || code2 == ORDERED)
3476 if (code2 == LEU || code2 == NE)
3481 if (code2 == GEU || code2 == NE)
3497 /* Return 1 if INSN is an unconditional jump and nothing else. */
3503 return (GET_CODE (insn) == JUMP_INSN
3504 && GET_CODE (PATTERN (insn)) == SET
3505 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
3506 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
3509 /* Return nonzero if INSN is a (possibly) conditional jump
3510 and nothing more. */
3516 register rtx x = PATTERN (insn);
3518 if (GET_CODE (x) != SET
3519 || GET_CODE (SET_DEST (x)) != PC)
3523 if (GET_CODE (x) == LABEL_REF)
3525 else return (GET_CODE (x) == IF_THEN_ELSE
3526 && ((GET_CODE (XEXP (x, 2)) == PC
3527 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
3528 || GET_CODE (XEXP (x, 1)) == RETURN))
3529 || (GET_CODE (XEXP (x, 1)) == PC
3530 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
3531 || GET_CODE (XEXP (x, 2)) == RETURN))));
3536 /* Return nonzero if INSN is a (possibly) conditional jump inside a
3540 condjump_in_parallel_p (insn)
3543 register rtx x = PATTERN (insn);
3545 if (GET_CODE (x) != PARALLEL)
3548 x = XVECEXP (x, 0, 0);
3550 if (GET_CODE (x) != SET)
3552 if (GET_CODE (SET_DEST (x)) != PC)
3554 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
3556 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
3558 if (XEXP (SET_SRC (x), 2) == pc_rtx
3559 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
3560 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
3562 if (XEXP (SET_SRC (x), 1) == pc_rtx
3563 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
3564 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
3569 /* Return the label of a conditional jump. */
3572 condjump_label (insn)
3575 register rtx x = PATTERN (insn);
3577 if (GET_CODE (x) == PARALLEL)
3578 x = XVECEXP (x, 0, 0);
3579 if (GET_CODE (x) != SET)
3581 if (GET_CODE (SET_DEST (x)) != PC)
3584 if (GET_CODE (x) == LABEL_REF)
3586 if (GET_CODE (x) != IF_THEN_ELSE)
3588 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
3590 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
3595 /* Return true if INSN is a (possibly conditional) return insn. */
3598 returnjump_p_1 (loc, data)
3600 void *data ATTRIBUTE_UNUSED;
3603 return x && GET_CODE (x) == RETURN;
3610 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
3613 /* Return true if INSN is a jump that only transfers control and
3622 if (GET_CODE (insn) != JUMP_INSN)
3625 set = single_set (insn);
3628 if (GET_CODE (SET_DEST (set)) != PC)
3630 if (side_effects_p (SET_SRC (set)))
3638 /* Return 1 if X is an RTX that does nothing but set the condition codes
3639 and CLOBBER or USE registers.
3640 Return -1 if X does explicitly set the condition codes,
3641 but also does other things. */
3645 rtx x ATTRIBUTE_UNUSED;
3647 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
3649 if (GET_CODE (x) == PARALLEL)
3653 int other_things = 0;
3654 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
3656 if (GET_CODE (XVECEXP (x, 0, i)) == SET
3657 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
3659 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
3662 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
3668 /* Follow any unconditional jump at LABEL;
3669 return the ultimate label reached by any such chain of jumps.
3670 If LABEL is not followed by a jump, return LABEL.
3671 If the chain loops or we can't find end, return LABEL,
3672 since that tells caller to avoid changing the insn.
3674 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
3675 a USE or CLOBBER. */
3678 follow_jumps (label)
3683 register rtx value = label;
3688 && (insn = next_active_insn (value)) != 0
3689 && GET_CODE (insn) == JUMP_INSN
3690 && ((JUMP_LABEL (insn) != 0 && simplejump_p (insn))
3691 || GET_CODE (PATTERN (insn)) == RETURN)
3692 && (next = NEXT_INSN (insn))
3693 && GET_CODE (next) == BARRIER);
3696 /* Don't chain through the insn that jumps into a loop
3697 from outside the loop,
3698 since that would create multiple loop entry jumps
3699 and prevent loop optimization. */
3701 if (!reload_completed)
3702 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
3703 if (GET_CODE (tem) == NOTE
3704 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
3705 /* ??? Optional. Disables some optimizations, but makes
3706 gcov output more accurate with -O. */
3707 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
3710 /* If we have found a cycle, make the insn jump to itself. */
3711 if (JUMP_LABEL (insn) == label)
3714 tem = next_active_insn (JUMP_LABEL (insn));
3715 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
3716 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
3719 value = JUMP_LABEL (insn);
3726 /* Assuming that field IDX of X is a vector of label_refs,
3727 replace each of them by the ultimate label reached by it.
3728 Return nonzero if a change is made.
3729 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
3732 tension_vector_labels (x, idx)
3738 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
3740 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
3741 register rtx nlabel = follow_jumps (olabel);
3742 if (nlabel && nlabel != olabel)
3744 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
3745 ++LABEL_NUSES (nlabel);
3746 if (--LABEL_NUSES (olabel) == 0)
3747 delete_insn (olabel);
3754 /* Find all CODE_LABELs referred to in X, and increment their use counts.
3755 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
3756 in INSN, then store one of them in JUMP_LABEL (INSN).
3757 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
3758 referenced in INSN, add a REG_LABEL note containing that label to INSN.
3759 Also, when there are consecutive labels, canonicalize on the last of them.
3761 Note that two labels separated by a loop-beginning note
3762 must be kept distinct if we have not yet done loop-optimization,
3763 because the gap between them is where loop-optimize
3764 will want to move invariant code to. CROSS_JUMP tells us
3765 that loop-optimization is done with.
3767 Once reload has completed (CROSS_JUMP non-zero), we need not consider
3768 two labels distinct if they are separated by only USE or CLOBBER insns. */
3771 mark_jump_label (x, insn, cross_jump, in_mem)
3777 register RTX_CODE code = GET_CODE (x);
3779 register const char *fmt;
3801 /* If this is a constant-pool reference, see if it is a label. */
3802 if (CONSTANT_POOL_ADDRESS_P (x))
3803 mark_jump_label (get_pool_constant (x), insn, cross_jump, in_mem);
3808 rtx label = XEXP (x, 0);
3813 if (GET_CODE (label) != CODE_LABEL)
3816 /* Ignore references to labels of containing functions. */
3817 if (LABEL_REF_NONLOCAL_P (x))
3820 /* If there are other labels following this one,
3821 replace it with the last of the consecutive labels. */
3822 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
3824 if (GET_CODE (next) == CODE_LABEL)
3826 else if (cross_jump && GET_CODE (next) == INSN
3827 && (GET_CODE (PATTERN (next)) == USE
3828 || GET_CODE (PATTERN (next)) == CLOBBER))
3830 else if (GET_CODE (next) != NOTE)
3832 else if (! cross_jump
3833 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
3834 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
3835 /* ??? Optional. Disables some optimizations, but
3836 makes gcov output more accurate with -O. */
3837 || (flag_test_coverage && NOTE_LINE_NUMBER (next) > 0)))
3841 XEXP (x, 0) = label;
3842 if (! insn || ! INSN_DELETED_P (insn))
3843 ++LABEL_NUSES (label);
3847 if (GET_CODE (insn) == JUMP_INSN)
3848 JUMP_LABEL (insn) = label;
3850 /* If we've changed OLABEL and we had a REG_LABEL note
3851 for it, update it as well. */
3852 else if (label != olabel
3853 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
3854 XEXP (note, 0) = label;
3856 /* Otherwise, add a REG_LABEL note for LABEL unless there already
3858 else if (! find_reg_note (insn, REG_LABEL, label))
3860 /* This code used to ignore labels which refered to dispatch
3861 tables to avoid flow.c generating worse code.
3863 However, in the presense of global optimizations like
3864 gcse which call find_basic_blocks without calling
3865 life_analysis, not recording such labels will lead
3866 to compiler aborts because of inconsistencies in the
3867 flow graph. So we go ahead and record the label.
3869 It may also be the case that the optimization argument
3870 is no longer valid because of the more accurate cfg
3871 we build in find_basic_blocks -- it no longer pessimizes
3872 code when it finds a REG_LABEL note. */
3873 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_LABEL, label,
3880 /* Do walk the labels in a vector, but not the first operand of an
3881 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
3884 if (! INSN_DELETED_P (insn))
3886 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
3888 for (i = 0; i < XVECLEN (x, eltnum); i++)
3889 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX,
3890 cross_jump, in_mem);
3898 fmt = GET_RTX_FORMAT (code);
3899 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3902 mark_jump_label (XEXP (x, i), insn, cross_jump, in_mem);
3903 else if (fmt[i] == 'E')
3906 for (j = 0; j < XVECLEN (x, i); j++)
3907 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump, in_mem);
3912 /* If all INSN does is set the pc, delete it,
3913 and delete the insn that set the condition codes for it
3914 if that's what the previous thing was. */
3920 register rtx set = single_set (insn);
3922 if (set && GET_CODE (SET_DEST (set)) == PC)
3923 delete_computation (insn);
3926 /* Verify INSN is a BARRIER and delete it. */
3929 delete_barrier (insn)
3932 if (GET_CODE (insn) != BARRIER)
3938 /* Recursively delete prior insns that compute the value (used only by INSN
3939 which the caller is deleting) stored in the register mentioned by NOTE
3940 which is a REG_DEAD note associated with INSN. */
3943 delete_prior_computation (note, insn)
3948 rtx reg = XEXP (note, 0);
3950 for (our_prev = prev_nonnote_insn (insn);
3951 our_prev && (GET_CODE (our_prev) == INSN
3952 || GET_CODE (our_prev) == CALL_INSN);
3953 our_prev = prev_nonnote_insn (our_prev))
3955 rtx pat = PATTERN (our_prev);
3957 /* If we reach a CALL which is not calling a const function
3958 or the callee pops the arguments, then give up. */
3959 if (GET_CODE (our_prev) == CALL_INSN
3960 && (! CONST_CALL_P (our_prev)
3961 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
3964 /* If we reach a SEQUENCE, it is too complex to try to
3965 do anything with it, so give up. */
3966 if (GET_CODE (pat) == SEQUENCE)
3969 if (GET_CODE (pat) == USE
3970 && GET_CODE (XEXP (pat, 0)) == INSN)
3971 /* reorg creates USEs that look like this. We leave them
3972 alone because reorg needs them for its own purposes. */
3975 if (reg_set_p (reg, pat))
3977 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
3980 if (GET_CODE (pat) == PARALLEL)
3982 /* If we find a SET of something else, we can't
3987 for (i = 0; i < XVECLEN (pat, 0); i++)
3989 rtx part = XVECEXP (pat, 0, i);
3991 if (GET_CODE (part) == SET
3992 && SET_DEST (part) != reg)
3996 if (i == XVECLEN (pat, 0))
3997 delete_computation (our_prev);
3999 else if (GET_CODE (pat) == SET
4000 && GET_CODE (SET_DEST (pat)) == REG)
4002 int dest_regno = REGNO (SET_DEST (pat));
4004 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4005 ? HARD_REGNO_NREGS (dest_regno,
4006 GET_MODE (SET_DEST (pat))) : 1);
4007 int regno = REGNO (reg);
4008 int endregno = regno + (regno < FIRST_PSEUDO_REGISTER
4009 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1);
4011 if (dest_regno >= regno
4012 && dest_endregno <= endregno)
4013 delete_computation (our_prev);
4015 /* We may have a multi-word hard register and some, but not
4016 all, of the words of the register are needed in subsequent
4017 insns. Write REG_UNUSED notes for those parts that were not
4019 else if (dest_regno <= regno
4020 && dest_endregno >= endregno)
4024 REG_NOTES (our_prev)
4025 = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (our_prev));
4027 for (i = dest_regno; i < dest_endregno; i++)
4028 if (! find_regno_note (our_prev, REG_UNUSED, i))
4031 if (i == dest_endregno)
4032 delete_computation (our_prev);
4039 /* If PAT references the register that dies here, it is an
4040 additional use. Hence any prior SET isn't dead. However, this
4041 insn becomes the new place for the REG_DEAD note. */
4042 if (reg_overlap_mentioned_p (reg, pat))
4044 XEXP (note, 1) = REG_NOTES (our_prev);
4045 REG_NOTES (our_prev) = note;
4051 /* Delete INSN and recursively delete insns that compute values used only
4052 by INSN. This uses the REG_DEAD notes computed during flow analysis.
4053 If we are running before flow.c, we need do nothing since flow.c will
4054 delete dead code. We also can't know if the registers being used are
4055 dead or not at this point.
4057 Otherwise, look at all our REG_DEAD notes. If a previous insn does
4058 nothing other than set a register that dies in this insn, we can delete
4061 On machines with CC0, if CC0 is used in this insn, we may be able to
4062 delete the insn that set it. */
4065 delete_computation (insn)
4072 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
4074 rtx prev = prev_nonnote_insn (insn);
4075 /* We assume that at this stage
4076 CC's are always set explicitly
4077 and always immediately before the jump that
4078 will use them. So if the previous insn
4079 exists to set the CC's, delete it
4080 (unless it performs auto-increments, etc.). */
4081 if (prev && GET_CODE (prev) == INSN
4082 && sets_cc0_p (PATTERN (prev)))
4084 if (sets_cc0_p (PATTERN (prev)) > 0
4085 && ! side_effects_p (PATTERN (prev)))
4086 delete_computation (prev);
4088 /* Otherwise, show that cc0 won't be used. */
4089 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
4090 cc0_rtx, REG_NOTES (prev));
4095 #ifdef INSN_SCHEDULING
4096 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
4097 reload has completed. The schedulers need to be fixed. Until
4098 they are, we must not rely on the death notes here. */
4099 if (reload_completed && flag_schedule_insns_after_reload)
4106 /* The REG_DEAD note may have been omitted for a register
4107 which is both set and used by the insn. */
4108 set = single_set (insn);
4109 if (set && GET_CODE (SET_DEST (set)) == REG)
4111 int dest_regno = REGNO (SET_DEST (set));
4113 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4114 ? HARD_REGNO_NREGS (dest_regno,
4115 GET_MODE (SET_DEST (set))) : 1);
4118 for (i = dest_regno; i < dest_endregno; i++)
4120 if (! refers_to_regno_p (i, i + 1, SET_SRC (set), NULL_PTR)
4121 || find_regno_note (insn, REG_DEAD, i))
4124 note = gen_rtx_EXPR_LIST (REG_DEAD, (i < FIRST_PSEUDO_REGISTER
4125 ? gen_rtx_REG (reg_raw_mode[i], i)
4126 : SET_DEST (set)), NULL_RTX);
4127 delete_prior_computation (note, insn);
4131 for (note = REG_NOTES (insn); note; note = next)
4133 next = XEXP (note, 1);
4135 if (REG_NOTE_KIND (note) != REG_DEAD
4136 /* Verify that the REG_NOTE is legitimate. */
4137 || GET_CODE (XEXP (note, 0)) != REG)
4140 delete_prior_computation (note, insn);
4146 /* Delete insn INSN from the chain of insns and update label ref counts.
4147 May delete some following insns as a consequence; may even delete
4148 a label elsewhere and insns that follow it.
4150 Returns the first insn after INSN that was not deleted. */
4156 register rtx next = NEXT_INSN (insn);
4157 register rtx prev = PREV_INSN (insn);
4158 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
4159 register int dont_really_delete = 0;
4161 while (next && INSN_DELETED_P (next))
4162 next = NEXT_INSN (next);
4164 /* This insn is already deleted => return first following nondeleted. */
4165 if (INSN_DELETED_P (insn))
4169 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
4171 /* Don't delete user-declared labels. When optimizing, convert them
4172 to special NOTEs instead. When not optimizing, leave them alone. */
4173 if (was_code_label && LABEL_NAME (insn) != 0)
4176 dont_really_delete = 1;
4177 else if (! dont_really_delete)
4179 PUT_CODE (insn, NOTE);
4180 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
4181 NOTE_SOURCE_FILE (insn) = 0;
4182 dont_really_delete = 1;
4186 /* Mark this insn as deleted. */
4187 INSN_DELETED_P (insn) = 1;
4189 /* If this is an unconditional jump, delete it from the jump chain. */
4190 if (simplejump_p (insn))
4191 delete_from_jump_chain (insn);
4193 /* If instruction is followed by a barrier,
4194 delete the barrier too. */
4196 if (next != 0 && GET_CODE (next) == BARRIER)
4198 INSN_DELETED_P (next) = 1;
4199 next = NEXT_INSN (next);
4202 /* Patch out INSN (and the barrier if any) */
4204 if (! dont_really_delete)
4208 NEXT_INSN (prev) = next;
4209 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
4210 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
4211 XVECLEN (PATTERN (prev), 0) - 1)) = next;
4216 PREV_INSN (next) = prev;
4217 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
4218 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
4221 if (prev && NEXT_INSN (prev) == 0)
4222 set_last_insn (prev);
4225 /* If deleting a jump, decrement the count of the label,
4226 and delete the label if it is now unused. */
4228 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
4230 rtx lab = JUMP_LABEL (insn), lab_next;
4232 if (--LABEL_NUSES (lab) == 0)
4234 /* This can delete NEXT or PREV,
4235 either directly if NEXT is JUMP_LABEL (INSN),
4236 or indirectly through more levels of jumps. */
4239 /* I feel a little doubtful about this loop,
4240 but I see no clean and sure alternative way
4241 to find the first insn after INSN that is not now deleted.
4242 I hope this works. */
4243 while (next && INSN_DELETED_P (next))
4244 next = NEXT_INSN (next);
4247 else if ((lab_next = next_nonnote_insn (lab)) != NULL
4248 && GET_CODE (lab_next) == JUMP_INSN
4249 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
4250 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
4252 /* If we're deleting the tablejump, delete the dispatch table.
4253 We may not be able to kill the label immediately preceeding
4254 just yet, as it might be referenced in code leading up to
4256 delete_insn (lab_next);
4260 /* Likewise if we're deleting a dispatch table. */
4262 if (GET_CODE (insn) == JUMP_INSN
4263 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
4264 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
4266 rtx pat = PATTERN (insn);
4267 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
4268 int len = XVECLEN (pat, diff_vec_p);
4270 for (i = 0; i < len; i++)
4271 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
4272 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
4273 while (next && INSN_DELETED_P (next))
4274 next = NEXT_INSN (next);
4278 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
4279 prev = PREV_INSN (prev);
4281 /* If INSN was a label and a dispatch table follows it,
4282 delete the dispatch table. The tablejump must have gone already.
4283 It isn't useful to fall through into a table. */
4286 && NEXT_INSN (insn) != 0
4287 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
4288 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
4289 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
4290 next = delete_insn (NEXT_INSN (insn));
4292 /* If INSN was a label, delete insns following it if now unreachable. */
4294 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
4296 register RTX_CODE code;
4298 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
4299 || code == NOTE || code == BARRIER
4300 || (code == CODE_LABEL && INSN_DELETED_P (next))))
4303 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
4304 next = NEXT_INSN (next);
4305 /* Keep going past other deleted labels to delete what follows. */
4306 else if (code == CODE_LABEL && INSN_DELETED_P (next))
4307 next = NEXT_INSN (next);
4309 /* Note: if this deletes a jump, it can cause more
4310 deletion of unreachable code, after a different label.
4311 As long as the value from this recursive call is correct,
4312 this invocation functions correctly. */
4313 next = delete_insn (next);
4320 /* Advance from INSN till reaching something not deleted
4321 then return that. May return INSN itself. */
4324 next_nondeleted_insn (insn)
4327 while (INSN_DELETED_P (insn))
4328 insn = NEXT_INSN (insn);
4332 /* Delete a range of insns from FROM to TO, inclusive.
4333 This is for the sake of peephole optimization, so assume
4334 that whatever these insns do will still be done by a new
4335 peephole insn that will replace them. */
4338 delete_for_peephole (from, to)
4339 register rtx from, to;
4341 register rtx insn = from;
4345 register rtx next = NEXT_INSN (insn);
4346 register rtx prev = PREV_INSN (insn);
4348 if (GET_CODE (insn) != NOTE)
4350 INSN_DELETED_P (insn) = 1;
4352 /* Patch this insn out of the chain. */
4353 /* We don't do this all at once, because we
4354 must preserve all NOTEs. */
4356 NEXT_INSN (prev) = next;
4359 PREV_INSN (next) = prev;
4367 /* Note that if TO is an unconditional jump
4368 we *do not* delete the BARRIER that follows,
4369 since the peephole that replaces this sequence
4370 is also an unconditional jump in that case. */
4373 /* We have determined that INSN is never reached, and are about to
4374 delete it. Print a warning if the user asked for one.
4376 To try to make this warning more useful, this should only be called
4377 once per basic block not reached, and it only warns when the basic
4378 block contains more than one line from the current function, and
4379 contains at least one operation. CSE and inlining can duplicate insns,
4380 so it's possible to get spurious warnings from this. */
4383 never_reached_warning (avoided_insn)
4387 rtx a_line_note = NULL;
4388 int two_avoided_lines = 0;
4389 int contains_insn = 0;
4391 if (! warn_notreached)
4394 /* Scan forwards, looking at LINE_NUMBER notes, until
4395 we hit a LABEL or we run out of insns. */
4397 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
4399 if (GET_CODE (insn) == CODE_LABEL)
4401 else if (GET_CODE (insn) == NOTE /* A line number note? */
4402 && NOTE_LINE_NUMBER (insn) >= 0)
4404 if (a_line_note == NULL)
4407 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
4408 != NOTE_LINE_NUMBER (insn));
4410 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
4413 if (two_avoided_lines && contains_insn)
4414 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
4415 NOTE_LINE_NUMBER (a_line_note),
4416 "will never be executed");
4419 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
4420 NLABEL as a return. Accrue modifications into the change group. */
4423 redirect_exp_1 (loc, olabel, nlabel, insn)
4428 register rtx x = *loc;
4429 register RTX_CODE code = GET_CODE (x);
4431 register const char *fmt;
4433 if (code == LABEL_REF)
4435 if (XEXP (x, 0) == olabel)
4439 n = gen_rtx_LABEL_REF (VOIDmode, nlabel);
4441 n = gen_rtx_RETURN (VOIDmode);
4443 validate_change (insn, loc, n, 1);
4447 else if (code == RETURN && olabel == 0)
4449 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
4450 if (loc == &PATTERN (insn))
4451 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
4452 validate_change (insn, loc, x, 1);
4456 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
4457 && GET_CODE (SET_SRC (x)) == LABEL_REF
4458 && XEXP (SET_SRC (x), 0) == olabel)
4460 validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1);
4464 fmt = GET_RTX_FORMAT (code);
4465 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4468 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
4469 else if (fmt[i] == 'E')
4472 for (j = 0; j < XVECLEN (x, i); j++)
4473 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
4478 /* Similar, but apply the change group and report success or failure. */
4481 redirect_exp (loc, olabel, nlabel, insn)
4486 redirect_exp_1 (loc, olabel, nlabel, insn);
4487 if (num_validated_changes () == 0)
4490 return apply_change_group ();
4493 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
4494 the modifications into the change group. Return false if we did
4495 not see how to do that. */
4498 redirect_jump_1 (jump, nlabel)
4501 int ochanges = num_validated_changes ();
4502 redirect_exp_1 (&PATTERN (jump), JUMP_LABEL (jump), nlabel, jump);
4503 return num_validated_changes () > ochanges;
4506 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
4507 jump target label is unused as a result, it and the code following
4510 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
4513 The return value will be 1 if the change was made, 0 if it wasn't
4514 (this can only occur for NLABEL == 0). */
4517 redirect_jump (jump, nlabel)
4520 register rtx olabel = JUMP_LABEL (jump);
4522 if (nlabel == olabel)
4525 if (! redirect_exp (&PATTERN (jump), olabel, nlabel, jump))
4528 /* If this is an unconditional branch, delete it from the jump_chain of
4529 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
4530 have UID's in range and JUMP_CHAIN is valid). */
4531 if (jump_chain && (simplejump_p (jump)
4532 || GET_CODE (PATTERN (jump)) == RETURN))
4534 int label_index = nlabel ? INSN_UID (nlabel) : 0;
4536 delete_from_jump_chain (jump);
4537 if (label_index < max_jump_chain
4538 && INSN_UID (jump) < max_jump_chain)
4540 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
4541 jump_chain[label_index] = jump;
4545 JUMP_LABEL (jump) = nlabel;
4547 ++LABEL_NUSES (nlabel);
4549 /* If we're eliding the jump over exception cleanups at the end of a
4550 function, move the function end note so that -Wreturn-type works. */
4551 if (olabel && NEXT_INSN (olabel)
4552 && GET_CODE (NEXT_INSN (olabel)) == NOTE
4553 && NOTE_LINE_NUMBER (NEXT_INSN (olabel)) == NOTE_INSN_FUNCTION_END)
4554 emit_note_after (NOTE_INSN_FUNCTION_END, nlabel);
4556 if (olabel && --LABEL_NUSES (olabel) == 0)
4557 delete_insn (olabel);
4562 /* Invert the jump condition of rtx X contained in jump insn, INSN.
4563 Accrue the modifications into the change group. */
4566 invert_exp_1 (x, insn)
4570 register RTX_CODE code;
4572 register const char *fmt;
4574 code = GET_CODE (x);
4576 if (code == IF_THEN_ELSE)
4578 register rtx comp = XEXP (x, 0);
4581 /* We can do this in two ways: The preferable way, which can only
4582 be done if this is not an integer comparison, is to reverse
4583 the comparison code. Otherwise, swap the THEN-part and ELSE-part
4584 of the IF_THEN_ELSE. If we can't do either, fail. */
4586 if (can_reverse_comparison_p (comp, insn))
4588 validate_change (insn, &XEXP (x, 0),
4589 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
4590 GET_MODE (comp), XEXP (comp, 0),
4597 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
4598 validate_change (insn, &XEXP (x, 2), tem, 1);
4602 fmt = GET_RTX_FORMAT (code);
4603 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4606 invert_exp_1 (XEXP (x, i), insn);
4607 else if (fmt[i] == 'E')
4610 for (j = 0; j < XVECLEN (x, i); j++)
4611 invert_exp_1 (XVECEXP (x, i, j), insn);
4616 /* Invert the jump condition of rtx X contained in jump insn, INSN.
4618 Return 1 if we can do so, 0 if we cannot find a way to do so that
4619 matches a pattern. */
4622 invert_exp (x, insn)
4626 invert_exp_1 (x, insn);
4627 if (num_validated_changes () == 0)
4630 return apply_change_group ();
4633 /* Invert the condition of the jump JUMP, and make it jump to label
4634 NLABEL instead of where it jumps now. Accrue changes into the
4635 change group. Return false if we didn't see how to perform the
4636 inversion and redirection. */
4639 invert_jump_1 (jump, nlabel)
4644 ochanges = num_validated_changes ();
4645 invert_exp_1 (PATTERN (jump), jump);
4646 if (num_validated_changes () == ochanges)
4649 return redirect_jump_1 (jump, nlabel);
4652 /* Invert the condition of the jump JUMP, and make it jump to label
4653 NLABEL instead of where it jumps now. Return true if successful. */
4656 invert_jump (jump, nlabel)
4659 /* We have to either invert the condition and change the label or
4660 do neither. Either operation could fail. We first try to invert
4661 the jump. If that succeeds, we try changing the label. If that fails,
4662 we invert the jump back to what it was. */
4664 if (! invert_exp (PATTERN (jump), jump))
4667 if (redirect_jump (jump, nlabel))
4669 /* An inverted jump means that a probability taken becomes a
4670 probability not taken. Subtract the branch probability from the
4671 probability base to convert it back to a taken probability. */
4673 rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
4675 XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
4680 if (! invert_exp (PATTERN (jump), jump))
4681 /* This should just be putting it back the way it was. */
4687 /* Delete the instruction JUMP from any jump chain it might be on. */
4690 delete_from_jump_chain (jump)
4694 rtx olabel = JUMP_LABEL (jump);
4696 /* Handle unconditional jumps. */
4697 if (jump_chain && olabel != 0
4698 && INSN_UID (olabel) < max_jump_chain
4699 && simplejump_p (jump))
4700 index = INSN_UID (olabel);
4701 /* Handle return insns. */
4702 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
4706 if (jump_chain[index] == jump)
4707 jump_chain[index] = jump_chain[INSN_UID (jump)];
4712 for (insn = jump_chain[index];
4714 insn = jump_chain[INSN_UID (insn)])
4715 if (jump_chain[INSN_UID (insn)] == jump)
4717 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
4723 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
4725 If the old jump target label (before the dispatch table) becomes unused,
4726 it and the dispatch table may be deleted. In that case, find the insn
4727 before the jump references that label and delete it and logical successors
4731 redirect_tablejump (jump, nlabel)
4734 register rtx olabel = JUMP_LABEL (jump);
4736 /* Add this jump to the jump_chain of NLABEL. */
4737 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
4738 && INSN_UID (jump) < max_jump_chain)
4740 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
4741 jump_chain[INSN_UID (nlabel)] = jump;
4744 PATTERN (jump) = gen_jump (nlabel);
4745 JUMP_LABEL (jump) = nlabel;
4746 ++LABEL_NUSES (nlabel);
4747 INSN_CODE (jump) = -1;
4749 if (--LABEL_NUSES (olabel) == 0)
4751 delete_labelref_insn (jump, olabel, 0);
4752 delete_insn (olabel);
4756 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
4757 If we found one, delete it and then delete this insn if DELETE_THIS is
4758 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
4761 delete_labelref_insn (insn, label, delete_this)
4768 if (GET_CODE (insn) != NOTE
4769 && reg_mentioned_p (label, PATTERN (insn)))
4780 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
4781 if (delete_labelref_insn (XEXP (link, 0), label, 1))
4795 /* Like rtx_equal_p except that it considers two REGs as equal
4796 if they renumber to the same value and considers two commutative
4797 operations to be the same if the order of the operands has been
4800 ??? Addition is not commutative on the PA due to the weird implicit
4801 space register selection rules for memory addresses. Therefore, we
4802 don't consider a + b == b + a.
4804 We could/should make this test a little tighter. Possibly only
4805 disabling it on the PA via some backend macro or only disabling this
4806 case when the PLUS is inside a MEM. */
4809 rtx_renumbered_equal_p (x, y)
4813 register RTX_CODE code = GET_CODE (x);
4814 register const char *fmt;
4819 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
4820 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
4821 && GET_CODE (SUBREG_REG (y)) == REG)))
4823 int reg_x = -1, reg_y = -1;
4824 int word_x = 0, word_y = 0;
4826 if (GET_MODE (x) != GET_MODE (y))
4829 /* If we haven't done any renumbering, don't
4830 make any assumptions. */
4831 if (reg_renumber == 0)
4832 return rtx_equal_p (x, y);
4836 reg_x = REGNO (SUBREG_REG (x));
4837 word_x = SUBREG_WORD (x);
4839 if (reg_renumber[reg_x] >= 0)
4841 reg_x = reg_renumber[reg_x] + word_x;
4849 if (reg_renumber[reg_x] >= 0)
4850 reg_x = reg_renumber[reg_x];
4853 if (GET_CODE (y) == SUBREG)
4855 reg_y = REGNO (SUBREG_REG (y));
4856 word_y = SUBREG_WORD (y);
4858 if (reg_renumber[reg_y] >= 0)
4860 reg_y = reg_renumber[reg_y];
4868 if (reg_renumber[reg_y] >= 0)
4869 reg_y = reg_renumber[reg_y];
4872 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
4875 /* Now we have disposed of all the cases
4876 in which different rtx codes can match. */
4877 if (code != GET_CODE (y))
4889 return INTVAL (x) == INTVAL (y);
4892 /* We can't assume nonlocal labels have their following insns yet. */
4893 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
4894 return XEXP (x, 0) == XEXP (y, 0);
4896 /* Two label-refs are equivalent if they point at labels
4897 in the same position in the instruction stream. */
4898 return (next_real_insn (XEXP (x, 0))
4899 == next_real_insn (XEXP (y, 0)));
4902 return XSTR (x, 0) == XSTR (y, 0);
4905 /* If we didn't match EQ equality above, they aren't the same. */
4912 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
4914 if (GET_MODE (x) != GET_MODE (y))
4917 /* For commutative operations, the RTX match if the operand match in any
4918 order. Also handle the simple binary and unary cases without a loop.
4920 ??? Don't consider PLUS a commutative operator; see comments above. */
4921 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
4923 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
4924 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
4925 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
4926 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
4927 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
4928 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
4929 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
4930 else if (GET_RTX_CLASS (code) == '1')
4931 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
4933 /* Compare the elements. If any pair of corresponding elements
4934 fail to match, return 0 for the whole things. */
4936 fmt = GET_RTX_FORMAT (code);
4937 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4943 if (XWINT (x, i) != XWINT (y, i))
4948 if (XINT (x, i) != XINT (y, i))
4953 if (strcmp (XSTR (x, i), XSTR (y, i)))
4958 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
4963 if (XEXP (x, i) != XEXP (y, i))
4970 if (XVECLEN (x, i) != XVECLEN (y, i))
4972 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4973 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
4984 /* If X is a hard register or equivalent to one or a subregister of one,
4985 return the hard register number. If X is a pseudo register that was not
4986 assigned a hard register, return the pseudo register number. Otherwise,
4987 return -1. Any rtx is valid for X. */
4993 if (GET_CODE (x) == REG)
4995 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
4996 return reg_renumber[REGNO (x)];
4999 if (GET_CODE (x) == SUBREG)
5001 int base = true_regnum (SUBREG_REG (x));
5002 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
5003 return SUBREG_WORD (x) + base;
5008 /* Optimize code of the form:
5010 for (x = a[i]; x; ...)
5012 for (x = a[i]; x; ...)
5016 Loop optimize will change the above code into
5020 { ...; if (! (x = ...)) break; }
5023 { ...; if (! (x = ...)) break; }
5026 In general, if the first test fails, the program can branch
5027 directly to `foo' and skip the second try which is doomed to fail.
5028 We run this after loop optimization and before flow analysis. */
5030 /* When comparing the insn patterns, we track the fact that different
5031 pseudo-register numbers may have been used in each computation.
5032 The following array stores an equivalence -- same_regs[I] == J means
5033 that pseudo register I was used in the first set of tests in a context
5034 where J was used in the second set. We also count the number of such
5035 pending equivalences. If nonzero, the expressions really aren't the
5038 static int *same_regs;
5040 static int num_same_regs;
5042 /* Track any registers modified between the target of the first jump and
5043 the second jump. They never compare equal. */
5045 static char *modified_regs;
5047 /* Record if memory was modified. */
5049 static int modified_mem;
5051 /* Called via note_stores on each insn between the target of the first
5052 branch and the second branch. It marks any changed registers. */
5055 mark_modified_reg (dest, x, data)
5057 rtx x ATTRIBUTE_UNUSED;
5058 void *data ATTRIBUTE_UNUSED;
5063 if (GET_CODE (dest) == SUBREG)
5064 dest = SUBREG_REG (dest);
5066 if (GET_CODE (dest) == MEM)
5069 if (GET_CODE (dest) != REG)
5072 regno = REGNO (dest);
5073 if (regno >= FIRST_PSEUDO_REGISTER)
5074 modified_regs[regno] = 1;
5076 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
5077 modified_regs[regno + i] = 1;
5080 /* F is the first insn in the chain of insns. */
5083 thread_jumps (f, max_reg, flag_before_loop)
5086 int flag_before_loop;
5088 /* Basic algorithm is to find a conditional branch,
5089 the label it may branch to, and the branch after
5090 that label. If the two branches test the same condition,
5091 walk back from both branch paths until the insn patterns
5092 differ, or code labels are hit. If we make it back to
5093 the target of the first branch, then we know that the first branch
5094 will either always succeed or always fail depending on the relative
5095 senses of the two branches. So adjust the first branch accordingly
5098 rtx label, b1, b2, t1, t2;
5099 enum rtx_code code1, code2;
5100 rtx b1op0, b1op1, b2op0, b2op1;
5105 /* Allocate register tables and quick-reset table. */
5106 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
5107 same_regs = (int *) xmalloc (max_reg * sizeof (int));
5108 all_reset = (int *) xmalloc (max_reg * sizeof (int));
5109 for (i = 0; i < max_reg; i++)
5116 for (b1 = f; b1; b1 = NEXT_INSN (b1))
5118 /* Get to a candidate branch insn. */
5119 if (GET_CODE (b1) != JUMP_INSN
5120 || ! condjump_p (b1) || simplejump_p (b1)
5121 || JUMP_LABEL (b1) == 0)
5124 bzero (modified_regs, max_reg * sizeof (char));
5127 bcopy ((char *) all_reset, (char *) same_regs,
5128 max_reg * sizeof (int));
5131 label = JUMP_LABEL (b1);
5133 /* Look for a branch after the target. Record any registers and
5134 memory modified between the target and the branch. Stop when we
5135 get to a label since we can't know what was changed there. */
5136 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
5138 if (GET_CODE (b2) == CODE_LABEL)
5141 else if (GET_CODE (b2) == JUMP_INSN)
5143 /* If this is an unconditional jump and is the only use of
5144 its target label, we can follow it. */
5145 if (simplejump_p (b2)
5146 && JUMP_LABEL (b2) != 0
5147 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
5149 b2 = JUMP_LABEL (b2);
5156 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
5159 if (GET_CODE (b2) == CALL_INSN)
5162 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
5163 if (call_used_regs[i] && ! fixed_regs[i]
5164 && i != STACK_POINTER_REGNUM
5165 && i != FRAME_POINTER_REGNUM
5166 && i != HARD_FRAME_POINTER_REGNUM
5167 && i != ARG_POINTER_REGNUM)
5168 modified_regs[i] = 1;
5171 note_stores (PATTERN (b2), mark_modified_reg, NULL);
5174 /* Check the next candidate branch insn from the label
5177 || GET_CODE (b2) != JUMP_INSN
5179 || ! condjump_p (b2)
5180 || simplejump_p (b2))
5183 /* Get the comparison codes and operands, reversing the
5184 codes if appropriate. If we don't have comparison codes,
5185 we can't do anything. */
5186 b1op0 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 0);
5187 b1op1 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 1);
5188 code1 = GET_CODE (XEXP (SET_SRC (PATTERN (b1)), 0));
5189 if (XEXP (SET_SRC (PATTERN (b1)), 1) == pc_rtx)
5190 code1 = reverse_condition (code1);
5192 b2op0 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 0);
5193 b2op1 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 1);
5194 code2 = GET_CODE (XEXP (SET_SRC (PATTERN (b2)), 0));
5195 if (XEXP (SET_SRC (PATTERN (b2)), 1) == pc_rtx)
5196 code2 = reverse_condition (code2);
5198 /* If they test the same things and knowing that B1 branches
5199 tells us whether or not B2 branches, check if we
5200 can thread the branch. */
5201 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
5202 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
5203 && (comparison_dominates_p (code1, code2)
5204 || (can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1)),
5207 && comparison_dominates_p (code1, reverse_condition (code2)))))
5210 t1 = prev_nonnote_insn (b1);
5211 t2 = prev_nonnote_insn (b2);
5213 while (t1 != 0 && t2 != 0)
5217 /* We have reached the target of the first branch.
5218 If there are no pending register equivalents,
5219 we know that this branch will either always
5220 succeed (if the senses of the two branches are
5221 the same) or always fail (if not). */
5224 if (num_same_regs != 0)
5227 if (comparison_dominates_p (code1, code2))
5228 new_label = JUMP_LABEL (b2);
5230 new_label = get_label_after (b2);
5232 if (JUMP_LABEL (b1) != new_label)
5234 rtx prev = PREV_INSN (new_label);
5236 if (flag_before_loop
5237 && GET_CODE (prev) == NOTE
5238 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
5240 /* Don't thread to the loop label. If a loop
5241 label is reused, loop optimization will
5242 be disabled for that loop. */
5243 new_label = gen_label_rtx ();
5244 emit_label_after (new_label, PREV_INSN (prev));
5246 changed |= redirect_jump (b1, new_label);
5251 /* If either of these is not a normal insn (it might be
5252 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
5253 have already been skipped above.) Similarly, fail
5254 if the insns are different. */
5255 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
5256 || recog_memoized (t1) != recog_memoized (t2)
5257 || ! rtx_equal_for_thread_p (PATTERN (t1),
5261 t1 = prev_nonnote_insn (t1);
5262 t2 = prev_nonnote_insn (t2);
5269 free (modified_regs);
5274 /* This is like RTX_EQUAL_P except that it knows about our handling of
5275 possibly equivalent registers and knows to consider volatile and
5276 modified objects as not equal.
5278 YINSN is the insn containing Y. */
5281 rtx_equal_for_thread_p (x, y, yinsn)
5287 register enum rtx_code code;
5288 register const char *fmt;
5290 code = GET_CODE (x);
5291 /* Rtx's of different codes cannot be equal. */
5292 if (code != GET_CODE (y))
5295 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
5296 (REG:SI x) and (REG:HI x) are NOT equivalent. */
5298 if (GET_MODE (x) != GET_MODE (y))
5301 /* For floating-point, consider everything unequal. This is a bit
5302 pessimistic, but this pass would only rarely do anything for FP
5304 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
5305 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
5308 /* For commutative operations, the RTX match if the operand match in any
5309 order. Also handle the simple binary and unary cases without a loop. */
5310 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5311 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5312 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
5313 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
5314 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
5315 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
5316 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5317 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
5318 else if (GET_RTX_CLASS (code) == '1')
5319 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5321 /* Handle special-cases first. */
5325 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
5328 /* If neither is user variable or hard register, check for possible
5330 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
5331 || REGNO (x) < FIRST_PSEUDO_REGISTER
5332 || REGNO (y) < FIRST_PSEUDO_REGISTER)
5335 if (same_regs[REGNO (x)] == -1)
5337 same_regs[REGNO (x)] = REGNO (y);
5340 /* If this is the first time we are seeing a register on the `Y'
5341 side, see if it is the last use. If not, we can't thread the
5342 jump, so mark it as not equivalent. */
5343 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
5349 return (same_regs[REGNO (x)] == (int) REGNO (y));
5354 /* If memory modified or either volatile, not equivalent.
5355 Else, check address. */
5356 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5359 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5362 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5368 /* Cancel a pending `same_regs' if setting equivalenced registers.
5369 Then process source. */
5370 if (GET_CODE (SET_DEST (x)) == REG
5371 && GET_CODE (SET_DEST (y)) == REG)
5373 if (same_regs[REGNO (SET_DEST (x))] == (int) REGNO (SET_DEST (y)))
5375 same_regs[REGNO (SET_DEST (x))] = -1;
5378 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
5382 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
5385 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
5388 return XEXP (x, 0) == XEXP (y, 0);
5391 return XSTR (x, 0) == XSTR (y, 0);
5400 fmt = GET_RTX_FORMAT (code);
5401 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5406 if (XWINT (x, i) != XWINT (y, i))
5412 if (XINT (x, i) != XINT (y, i))
5418 /* Two vectors must have the same length. */
5419 if (XVECLEN (x, i) != XVECLEN (y, i))
5422 /* And the corresponding elements must match. */
5423 for (j = 0; j < XVECLEN (x, i); j++)
5424 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
5425 XVECEXP (y, i, j), yinsn) == 0)
5430 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
5436 if (strcmp (XSTR (x, i), XSTR (y, i)))
5441 /* These are just backpointers, so they don't matter. */
5448 /* It is believed that rtx's at this level will never
5449 contain anything but integers and other rtx's,
5450 except for within LABEL_REFs and SYMBOL_REFs. */
5459 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
5460 /* Return the insn that NEW can be safely inserted in front of starting at
5461 the jump insn INSN. Return 0 if it is not safe to do this jump
5462 optimization. Note that NEW must contain a single set. */
5465 find_insert_position (insn, new)
5472 /* If NEW does not clobber, it is safe to insert NEW before INSN. */
5473 if (GET_CODE (PATTERN (new)) != PARALLEL)
5476 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5477 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5478 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5485 /* There is a good chance that the previous insn PREV sets the thing
5486 being clobbered (often the CC in a hard reg). If PREV does not
5487 use what NEW sets, we can insert NEW before PREV. */
5489 prev = prev_active_insn (insn);
5490 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5491 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5492 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5494 && ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5498 return reg_mentioned_p (SET_DEST (single_set (new)), prev) ? 0 : prev;
5500 #endif /* !HAVE_cc0 */
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