1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This is the pathetic reminder of old fame of the jump-optimization pass
23 of the compiler. Now it contains basically a set of utility functions to
26 Each CODE_LABEL has a count of the times it is used
27 stored in the LABEL_NUSES internal field, and each JUMP_INSN
28 has one label that it refers to stored in the
29 JUMP_LABEL internal field. With this we can detect labels that
30 become unused because of the deletion of all the jumps that
31 formerly used them. The JUMP_LABEL info is sometimes looked
34 The subroutines redirect_jump and invert_jump are used
35 from other passes as well. */
39 #include "coretypes.h"
44 #include "hard-reg-set.h"
46 #include "insn-config.h"
47 #include "insn-attr.h"
50 #include "basic-block.h"
53 #include "diagnostic-core.h"
57 #include "tree-pass.h"
60 /* Optimize jump y; x: ... y: jumpif... x?
61 Don't know if it is worth bothering with. */
62 /* Optimize two cases of conditional jump to conditional jump?
63 This can never delete any instruction or make anything dead,
64 or even change what is live at any point.
65 So perhaps let combiner do it. */
67 static void init_label_info (rtx);
68 static void mark_all_labels (rtx);
69 static void mark_jump_label_1 (rtx, rtx, bool, bool);
70 static void mark_jump_label_asm (rtx, rtx);
71 static void redirect_exp_1 (rtx *, rtx, rtx, rtx);
72 static int invert_exp_1 (rtx, rtx);
73 static int returnjump_p_1 (rtx *, void *);
75 /* Worker for rebuild_jump_labels and rebuild_jump_labels_chain. */
77 rebuild_jump_labels_1 (rtx f, bool count_forced)
81 timevar_push (TV_REBUILD_JUMP);
85 /* Keep track of labels used from static data; we don't track them
86 closely enough to delete them here, so make sure their reference
87 count doesn't drop to zero. */
90 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
91 if (LABEL_P (XEXP (insn, 0)))
92 LABEL_NUSES (XEXP (insn, 0))++;
93 timevar_pop (TV_REBUILD_JUMP);
96 /* This function rebuilds the JUMP_LABEL field and REG_LABEL_TARGET
97 notes in jumping insns and REG_LABEL_OPERAND notes in non-jumping
98 instructions and jumping insns that have labels as operands
101 rebuild_jump_labels (rtx f)
103 rebuild_jump_labels_1 (f, true);
106 /* This function is like rebuild_jump_labels, but doesn't run over
107 forced_labels. It can be used on insn chains that aren't the
108 main function chain. */
110 rebuild_jump_labels_chain (rtx chain)
112 rebuild_jump_labels_1 (chain, false);
115 /* Some old code expects exactly one BARRIER as the NEXT_INSN of a
116 non-fallthru insn. This is not generally true, as multiple barriers
117 may have crept in, or the BARRIER may be separated from the last
118 real insn by one or more NOTEs.
120 This simple pass moves barriers and removes duplicates so that the
124 cleanup_barriers (void)
126 rtx insn, next, prev;
127 for (insn = get_insns (); insn; insn = next)
129 next = NEXT_INSN (insn);
130 if (BARRIER_P (insn))
132 prev = prev_nonnote_insn (insn);
135 if (BARRIER_P (prev))
137 else if (prev != PREV_INSN (insn))
138 reorder_insns (insn, insn, prev);
144 struct rtl_opt_pass pass_cleanup_barriers =
148 "barriers", /* name */
150 cleanup_barriers, /* execute */
153 0, /* static_pass_number */
155 0, /* properties_required */
156 0, /* properties_provided */
157 0, /* properties_destroyed */
158 0, /* todo_flags_start */
159 0 /* todo_flags_finish */
164 /* Initialize LABEL_NUSES and JUMP_LABEL fields, add REG_LABEL_TARGET
165 for remaining targets for JUMP_P. Delete any REG_LABEL_OPERAND
166 notes whose labels don't occur in the insn any more. */
169 init_label_info (rtx f)
173 for (insn = f; insn; insn = NEXT_INSN (insn))
176 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
178 /* REG_LABEL_TARGET notes (including the JUMP_LABEL field) are
179 sticky and not reset here; that way we won't lose association
180 with a label when e.g. the source for a target register
181 disappears out of reach for targets that may use jump-target
182 registers. Jump transformations are supposed to transform
183 any REG_LABEL_TARGET notes. The target label reference in a
184 branch may disappear from the branch (and from the
185 instruction before it) for other reasons, like register
192 for (note = REG_NOTES (insn); note; note = next)
194 next = XEXP (note, 1);
195 if (REG_NOTE_KIND (note) == REG_LABEL_OPERAND
196 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
197 remove_note (insn, note);
203 /* A subroutine of mark_all_labels. Trivially propagate a simple label
204 load into a jump_insn that uses it. */
207 maybe_propagate_label_ref (rtx jump_insn, rtx prev_nonjump_insn)
209 rtx label_note, pc, pc_src;
211 pc = pc_set (jump_insn);
212 pc_src = pc != NULL ? SET_SRC (pc) : NULL;
213 label_note = find_reg_note (prev_nonjump_insn, REG_LABEL_OPERAND, NULL);
215 /* If the previous non-jump insn sets something to a label,
216 something that this jump insn uses, make that label the primary
217 target of this insn if we don't yet have any. That previous
218 insn must be a single_set and not refer to more than one label.
219 The jump insn must not refer to other labels as jump targets
220 and must be a plain (set (pc) ...), maybe in a parallel, and
221 may refer to the item being set only directly or as one of the
222 arms in an IF_THEN_ELSE. */
224 if (label_note != NULL && pc_src != NULL)
226 rtx label_set = single_set (prev_nonjump_insn);
227 rtx label_dest = label_set != NULL ? SET_DEST (label_set) : NULL;
229 if (label_set != NULL
230 /* The source must be the direct LABEL_REF, not a
231 PLUS, UNSPEC, IF_THEN_ELSE etc. */
232 && GET_CODE (SET_SRC (label_set)) == LABEL_REF
233 && (rtx_equal_p (label_dest, pc_src)
234 || (GET_CODE (pc_src) == IF_THEN_ELSE
235 && (rtx_equal_p (label_dest, XEXP (pc_src, 1))
236 || rtx_equal_p (label_dest, XEXP (pc_src, 2))))))
238 /* The CODE_LABEL referred to in the note must be the
239 CODE_LABEL in the LABEL_REF of the "set". We can
240 conveniently use it for the marker function, which
241 requires a LABEL_REF wrapping. */
242 gcc_assert (XEXP (label_note, 0) == XEXP (SET_SRC (label_set), 0));
244 mark_jump_label_1 (label_set, jump_insn, false, true);
246 gcc_assert (JUMP_LABEL (jump_insn) == XEXP (label_note, 0));
251 /* Mark the label each jump jumps to.
252 Combine consecutive labels, and count uses of labels. */
255 mark_all_labels (rtx f)
259 if (current_ir_type () == IR_RTL_CFGLAYOUT)
264 /* In cfglayout mode, we don't bother with trivial next-insn
265 propagation of LABEL_REFs into JUMP_LABEL. This will be
266 handled by other optimizers using better algorithms. */
267 FOR_BB_INSNS (bb, insn)
269 gcc_assert (! INSN_DELETED_P (insn));
270 if (NONDEBUG_INSN_P (insn))
271 mark_jump_label (PATTERN (insn), insn, 0);
274 /* In cfglayout mode, there may be non-insns between the
275 basic blocks. If those non-insns represent tablejump data,
276 they contain label references that we must record. */
277 for (insn = bb->il.rtl->header; insn; insn = NEXT_INSN (insn))
280 gcc_assert (JUMP_TABLE_DATA_P (insn));
281 mark_jump_label (PATTERN (insn), insn, 0);
283 for (insn = bb->il.rtl->footer; insn; insn = NEXT_INSN (insn))
286 gcc_assert (JUMP_TABLE_DATA_P (insn));
287 mark_jump_label (PATTERN (insn), insn, 0);
293 rtx prev_nonjump_insn = NULL;
294 for (insn = f; insn; insn = NEXT_INSN (insn))
296 if (INSN_DELETED_P (insn))
298 else if (LABEL_P (insn))
299 prev_nonjump_insn = NULL;
300 else if (NONDEBUG_INSN_P (insn))
302 mark_jump_label (PATTERN (insn), insn, 0);
305 if (JUMP_LABEL (insn) == NULL && prev_nonjump_insn != NULL)
306 maybe_propagate_label_ref (insn, prev_nonjump_insn);
309 prev_nonjump_insn = insn;
315 /* Given a comparison (CODE ARG0 ARG1), inside an insn, INSN, return a code
316 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
317 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
318 know whether it's source is floating point or integer comparison. Machine
319 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
320 to help this function avoid overhead in these cases. */
322 reversed_comparison_code_parts (enum rtx_code code, const_rtx arg0,
323 const_rtx arg1, const_rtx insn)
325 enum machine_mode mode;
327 /* If this is not actually a comparison, we can't reverse it. */
328 if (GET_RTX_CLASS (code) != RTX_COMPARE
329 && GET_RTX_CLASS (code) != RTX_COMM_COMPARE)
332 mode = GET_MODE (arg0);
333 if (mode == VOIDmode)
334 mode = GET_MODE (arg1);
336 /* First see if machine description supplies us way to reverse the
337 comparison. Give it priority over everything else to allow
338 machine description to do tricks. */
339 if (GET_MODE_CLASS (mode) == MODE_CC
340 && REVERSIBLE_CC_MODE (mode))
342 #ifdef REVERSE_CONDITION
343 return REVERSE_CONDITION (code, mode);
345 return reverse_condition (code);
349 /* Try a few special cases based on the comparison code. */
358 /* It is always safe to reverse EQ and NE, even for the floating
359 point. Similarly the unsigned comparisons are never used for
360 floating point so we can reverse them in the default way. */
361 return reverse_condition (code);
366 /* In case we already see unordered comparison, we can be sure to
367 be dealing with floating point so we don't need any more tests. */
368 return reverse_condition_maybe_unordered (code);
373 /* We don't have safe way to reverse these yet. */
379 if (GET_MODE_CLASS (mode) == MODE_CC || CC0_P (arg0))
382 /* Try to search for the comparison to determine the real mode.
383 This code is expensive, but with sane machine description it
384 will be never used, since REVERSIBLE_CC_MODE will return true
389 /* These CONST_CAST's are okay because prev_nonnote_insn just
390 returns its argument and we assign it to a const_rtx
392 for (prev = prev_nonnote_insn (CONST_CAST_RTX(insn));
393 prev != 0 && !LABEL_P (prev);
394 prev = prev_nonnote_insn (CONST_CAST_RTX(prev)))
396 const_rtx set = set_of (arg0, prev);
397 if (set && GET_CODE (set) == SET
398 && rtx_equal_p (SET_DEST (set), arg0))
400 rtx src = SET_SRC (set);
402 if (GET_CODE (src) == COMPARE)
404 rtx comparison = src;
405 arg0 = XEXP (src, 0);
406 mode = GET_MODE (arg0);
407 if (mode == VOIDmode)
408 mode = GET_MODE (XEXP (comparison, 1));
411 /* We can get past reg-reg moves. This may be useful for model
412 of i387 comparisons that first move flag registers around. */
419 /* If register is clobbered in some ununderstandable way,
426 /* Test for an integer condition, or a floating-point comparison
427 in which NaNs can be ignored. */
428 if (CONST_INT_P (arg0)
429 || (GET_MODE (arg0) != VOIDmode
430 && GET_MODE_CLASS (mode) != MODE_CC
431 && !HONOR_NANS (mode)))
432 return reverse_condition (code);
437 /* A wrapper around the previous function to take COMPARISON as rtx
438 expression. This simplifies many callers. */
440 reversed_comparison_code (const_rtx comparison, const_rtx insn)
442 if (!COMPARISON_P (comparison))
444 return reversed_comparison_code_parts (GET_CODE (comparison),
445 XEXP (comparison, 0),
446 XEXP (comparison, 1), insn);
449 /* Return comparison with reversed code of EXP.
450 Return NULL_RTX in case we fail to do the reversal. */
452 reversed_comparison (const_rtx exp, enum machine_mode mode)
454 enum rtx_code reversed_code = reversed_comparison_code (exp, NULL_RTX);
455 if (reversed_code == UNKNOWN)
458 return simplify_gen_relational (reversed_code, mode, VOIDmode,
459 XEXP (exp, 0), XEXP (exp, 1));
463 /* Given an rtx-code for a comparison, return the code for the negated
464 comparison. If no such code exists, return UNKNOWN.
466 WATCH OUT! reverse_condition is not safe to use on a jump that might
467 be acting on the results of an IEEE floating point comparison, because
468 of the special treatment of non-signaling nans in comparisons.
469 Use reversed_comparison_code instead. */
472 reverse_condition (enum rtx_code code)
514 /* Similar, but we're allowed to generate unordered comparisons, which
515 makes it safe for IEEE floating-point. Of course, we have to recognize
516 that the target will support them too... */
519 reverse_condition_maybe_unordered (enum rtx_code code)
557 /* Similar, but return the code when two operands of a comparison are swapped.
558 This IS safe for IEEE floating-point. */
561 swap_condition (enum rtx_code code)
603 /* Given a comparison CODE, return the corresponding unsigned comparison.
604 If CODE is an equality comparison or already an unsigned comparison,
608 unsigned_condition (enum rtx_code code)
634 /* Similarly, return the signed version of a comparison. */
637 signed_condition (enum rtx_code code)
663 /* Return nonzero if CODE1 is more strict than CODE2, i.e., if the
664 truth of CODE1 implies the truth of CODE2. */
667 comparison_dominates_p (enum rtx_code code1, enum rtx_code code2)
669 /* UNKNOWN comparison codes can happen as a result of trying to revert
671 They can't match anything, so we have to reject them here. */
672 if (code1 == UNKNOWN || code2 == UNKNOWN)
681 if (code2 == UNLE || code2 == UNGE)
686 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
692 if (code2 == UNLE || code2 == NE)
697 if (code2 == LE || code2 == NE || code2 == ORDERED || code2 == LTGT)
702 if (code2 == UNGE || code2 == NE)
707 if (code2 == GE || code2 == NE || code2 == ORDERED || code2 == LTGT)
713 if (code2 == ORDERED)
718 if (code2 == NE || code2 == ORDERED)
723 if (code2 == LEU || code2 == NE)
728 if (code2 == GEU || code2 == NE)
733 if (code2 == NE || code2 == UNEQ || code2 == UNLE || code2 == UNLT
734 || code2 == UNGE || code2 == UNGT)
745 /* Return 1 if INSN is an unconditional jump and nothing else. */
748 simplejump_p (const_rtx insn)
750 return (JUMP_P (insn)
751 && GET_CODE (PATTERN (insn)) == SET
752 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
753 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
756 /* Return nonzero if INSN is a (possibly) conditional jump
759 Use of this function is deprecated, since we need to support combined
760 branch and compare insns. Use any_condjump_p instead whenever possible. */
763 condjump_p (const_rtx insn)
765 const_rtx x = PATTERN (insn);
767 if (GET_CODE (x) != SET
768 || GET_CODE (SET_DEST (x)) != PC)
772 if (GET_CODE (x) == LABEL_REF)
775 return (GET_CODE (x) == IF_THEN_ELSE
776 && ((GET_CODE (XEXP (x, 2)) == PC
777 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
778 || GET_CODE (XEXP (x, 1)) == RETURN))
779 || (GET_CODE (XEXP (x, 1)) == PC
780 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
781 || GET_CODE (XEXP (x, 2)) == RETURN))));
784 /* Return nonzero if INSN is a (possibly) conditional jump inside a
787 Use this function is deprecated, since we need to support combined
788 branch and compare insns. Use any_condjump_p instead whenever possible. */
791 condjump_in_parallel_p (const_rtx insn)
793 const_rtx x = PATTERN (insn);
795 if (GET_CODE (x) != PARALLEL)
798 x = XVECEXP (x, 0, 0);
800 if (GET_CODE (x) != SET)
802 if (GET_CODE (SET_DEST (x)) != PC)
804 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
806 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
808 if (XEXP (SET_SRC (x), 2) == pc_rtx
809 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
810 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
812 if (XEXP (SET_SRC (x), 1) == pc_rtx
813 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
814 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
819 /* Return set of PC, otherwise NULL. */
822 pc_set (const_rtx insn)
827 pat = PATTERN (insn);
829 /* The set is allowed to appear either as the insn pattern or
830 the first set in a PARALLEL. */
831 if (GET_CODE (pat) == PARALLEL)
832 pat = XVECEXP (pat, 0, 0);
833 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
839 /* Return true when insn is an unconditional direct jump,
840 possibly bundled inside a PARALLEL. */
843 any_uncondjump_p (const_rtx insn)
845 const_rtx x = pc_set (insn);
848 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
850 if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
855 /* Return true when insn is a conditional jump. This function works for
856 instructions containing PC sets in PARALLELs. The instruction may have
857 various other effects so before removing the jump you must verify
860 Note that unlike condjump_p it returns false for unconditional jumps. */
863 any_condjump_p (const_rtx insn)
865 const_rtx x = pc_set (insn);
870 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
873 a = GET_CODE (XEXP (SET_SRC (x), 1));
874 b = GET_CODE (XEXP (SET_SRC (x), 2));
876 return ((b == PC && (a == LABEL_REF || a == RETURN))
877 || (a == PC && (b == LABEL_REF || b == RETURN)));
880 /* Return the label of a conditional jump. */
883 condjump_label (const_rtx insn)
885 rtx x = pc_set (insn);
890 if (GET_CODE (x) == LABEL_REF)
892 if (GET_CODE (x) != IF_THEN_ELSE)
894 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
896 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
901 /* Return true if INSN is a (possibly conditional) return insn. */
904 returnjump_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
911 switch (GET_CODE (x))
918 return SET_IS_RETURN_P (x);
925 /* Return TRUE if INSN is a return jump. */
928 returnjump_p (rtx insn)
932 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
935 /* Return true if INSN is a (possibly conditional) return insn. */
938 eh_returnjump_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
940 return *loc && GET_CODE (*loc) == EH_RETURN;
944 eh_returnjump_p (rtx insn)
948 return for_each_rtx (&PATTERN (insn), eh_returnjump_p_1, NULL);
951 /* Return true if INSN is a jump that only transfers control and
955 onlyjump_p (const_rtx insn)
962 set = single_set (insn);
965 if (GET_CODE (SET_DEST (set)) != PC)
967 if (side_effects_p (SET_SRC (set)))
975 /* Return nonzero if X is an RTX that only sets the condition codes
976 and has no side effects. */
979 only_sets_cc0_p (const_rtx x)
987 return sets_cc0_p (x) == 1 && ! side_effects_p (x);
990 /* Return 1 if X is an RTX that does nothing but set the condition codes
991 and CLOBBER or USE registers.
992 Return -1 if X does explicitly set the condition codes,
993 but also does other things. */
996 sets_cc0_p (const_rtx x)
1004 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
1006 if (GET_CODE (x) == PARALLEL)
1010 int other_things = 0;
1011 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
1013 if (GET_CODE (XVECEXP (x, 0, i)) == SET
1014 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
1016 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
1019 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
1025 /* Find all CODE_LABELs referred to in X, and increment their use
1026 counts. If INSN is a JUMP_INSN and there is at least one
1027 CODE_LABEL referenced in INSN as a jump target, then store the last
1028 one in JUMP_LABEL (INSN). For a tablejump, this must be the label
1029 for the ADDR_VEC. Store any other jump targets as REG_LABEL_TARGET
1030 notes. If INSN is an INSN or a CALL_INSN or non-target operands of
1031 a JUMP_INSN, and there is at least one CODE_LABEL referenced in
1032 INSN, add a REG_LABEL_OPERAND note containing that label to INSN.
1034 Note that two labels separated by a loop-beginning note
1035 must be kept distinct if we have not yet done loop-optimization,
1036 because the gap between them is where loop-optimize
1037 will want to move invariant code to. CROSS_JUMP tells us
1038 that loop-optimization is done with. */
1041 mark_jump_label (rtx x, rtx insn, int in_mem)
1043 rtx asmop = extract_asm_operands (x);
1045 mark_jump_label_asm (asmop, insn);
1047 mark_jump_label_1 (x, insn, in_mem != 0,
1048 (insn != NULL && x == PATTERN (insn) && JUMP_P (insn)));
1051 /* Worker function for mark_jump_label. IN_MEM is TRUE when X occurs
1052 within a (MEM ...). IS_TARGET is TRUE when X is to be treated as a
1053 jump-target; when the JUMP_LABEL field of INSN should be set or a
1054 REG_LABEL_TARGET note should be added, not a REG_LABEL_OPERAND
1058 mark_jump_label_1 (rtx x, rtx insn, bool in_mem, bool is_target)
1060 RTX_CODE code = GET_CODE (x);
1080 for (i = 0; i < XVECLEN (x, 0); i++)
1081 mark_jump_label (PATTERN (XVECEXP (x, 0, i)),
1082 XVECEXP (x, 0, i), 0);
1089 /* If this is a constant-pool reference, see if it is a label. */
1090 if (CONSTANT_POOL_ADDRESS_P (x))
1091 mark_jump_label_1 (get_pool_constant (x), insn, in_mem, is_target);
1094 /* Handle operands in the condition of an if-then-else as for a
1099 mark_jump_label_1 (XEXP (x, 0), insn, in_mem, false);
1100 mark_jump_label_1 (XEXP (x, 1), insn, in_mem, true);
1101 mark_jump_label_1 (XEXP (x, 2), insn, in_mem, true);
1106 rtx label = XEXP (x, 0);
1108 /* Ignore remaining references to unreachable labels that
1109 have been deleted. */
1111 && NOTE_KIND (label) == NOTE_INSN_DELETED_LABEL)
1114 gcc_assert (LABEL_P (label));
1116 /* Ignore references to labels of containing functions. */
1117 if (LABEL_REF_NONLOCAL_P (x))
1120 XEXP (x, 0) = label;
1121 if (! insn || ! INSN_DELETED_P (insn))
1122 ++LABEL_NUSES (label);
1127 /* Do not change a previous setting of JUMP_LABEL. If the
1128 JUMP_LABEL slot is occupied by a different label,
1129 create a note for this label. */
1130 && (JUMP_LABEL (insn) == NULL || JUMP_LABEL (insn) == label))
1131 JUMP_LABEL (insn) = label;
1135 = is_target ? REG_LABEL_TARGET : REG_LABEL_OPERAND;
1137 /* Add a REG_LABEL_OPERAND or REG_LABEL_TARGET note
1138 for LABEL unless there already is one. All uses of
1139 a label, except for the primary target of a jump,
1140 must have such a note. */
1141 if (! find_reg_note (insn, kind, label))
1142 add_reg_note (insn, kind, label);
1148 /* Do walk the labels in a vector, but not the first operand of an
1149 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
1152 if (! INSN_DELETED_P (insn))
1154 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
1156 for (i = 0; i < XVECLEN (x, eltnum); i++)
1157 mark_jump_label_1 (XVECEXP (x, eltnum, i), NULL_RTX, in_mem,
1166 fmt = GET_RTX_FORMAT (code);
1168 /* The primary target of a tablejump is the label of the ADDR_VEC,
1169 which is canonically mentioned *last* in the insn. To get it
1170 marked as JUMP_LABEL, we iterate over items in reverse order. */
1171 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1174 mark_jump_label_1 (XEXP (x, i), insn, in_mem, is_target);
1175 else if (fmt[i] == 'E')
1179 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
1180 mark_jump_label_1 (XVECEXP (x, i, j), insn, in_mem,
1186 /* Worker function for mark_jump_label. Handle asm insns specially.
1187 In particular, output operands need not be considered so we can
1188 avoid re-scanning the replicated asm_operand. Also, the asm_labels
1189 need to be considered targets. */
1192 mark_jump_label_asm (rtx asmop, rtx insn)
1196 for (i = ASM_OPERANDS_INPUT_LENGTH (asmop) - 1; i >= 0; --i)
1197 mark_jump_label_1 (ASM_OPERANDS_INPUT (asmop, i), insn, false, false);
1199 for (i = ASM_OPERANDS_LABEL_LENGTH (asmop) - 1; i >= 0; --i)
1200 mark_jump_label_1 (ASM_OPERANDS_LABEL (asmop, i), insn, false, true);
1203 /* Delete insn INSN from the chain of insns and update label ref counts
1204 and delete insns now unreachable.
1206 Returns the first insn after INSN that was not deleted.
1208 Usage of this instruction is deprecated. Use delete_insn instead and
1209 subsequent cfg_cleanup pass to delete unreachable code if needed. */
1212 delete_related_insns (rtx insn)
1214 int was_code_label = (LABEL_P (insn));
1216 rtx next = NEXT_INSN (insn), prev = PREV_INSN (insn);
1218 while (next && INSN_DELETED_P (next))
1219 next = NEXT_INSN (next);
1221 /* This insn is already deleted => return first following nondeleted. */
1222 if (INSN_DELETED_P (insn))
1227 /* If instruction is followed by a barrier,
1228 delete the barrier too. */
1230 if (next != 0 && BARRIER_P (next))
1233 /* If deleting a jump, decrement the count of the label,
1234 and delete the label if it is now unused. */
1236 if (JUMP_P (insn) && JUMP_LABEL (insn))
1238 rtx lab = JUMP_LABEL (insn), lab_next;
1240 if (LABEL_NUSES (lab) == 0)
1241 /* This can delete NEXT or PREV,
1242 either directly if NEXT is JUMP_LABEL (INSN),
1243 or indirectly through more levels of jumps. */
1244 delete_related_insns (lab);
1245 else if (tablejump_p (insn, NULL, &lab_next))
1247 /* If we're deleting the tablejump, delete the dispatch table.
1248 We may not be able to kill the label immediately preceding
1249 just yet, as it might be referenced in code leading up to
1251 delete_related_insns (lab_next);
1255 /* Likewise if we're deleting a dispatch table. */
1257 if (JUMP_TABLE_DATA_P (insn))
1259 rtx pat = PATTERN (insn);
1260 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1261 int len = XVECLEN (pat, diff_vec_p);
1263 for (i = 0; i < len; i++)
1264 if (LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
1265 delete_related_insns (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
1266 while (next && INSN_DELETED_P (next))
1267 next = NEXT_INSN (next);
1271 /* Likewise for any JUMP_P / INSN / CALL_INSN with a
1272 REG_LABEL_OPERAND or REG_LABEL_TARGET note. */
1274 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1275 if ((REG_NOTE_KIND (note) == REG_LABEL_OPERAND
1276 || REG_NOTE_KIND (note) == REG_LABEL_TARGET)
1277 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
1278 && LABEL_P (XEXP (note, 0)))
1279 if (LABEL_NUSES (XEXP (note, 0)) == 0)
1280 delete_related_insns (XEXP (note, 0));
1282 while (prev && (INSN_DELETED_P (prev) || NOTE_P (prev)))
1283 prev = PREV_INSN (prev);
1285 /* If INSN was a label and a dispatch table follows it,
1286 delete the dispatch table. The tablejump must have gone already.
1287 It isn't useful to fall through into a table. */
1290 && NEXT_INSN (insn) != 0
1291 && JUMP_TABLE_DATA_P (NEXT_INSN (insn)))
1292 next = delete_related_insns (NEXT_INSN (insn));
1294 /* If INSN was a label, delete insns following it if now unreachable. */
1296 if (was_code_label && prev && BARRIER_P (prev))
1301 code = GET_CODE (next);
1303 next = NEXT_INSN (next);
1304 /* Keep going past other deleted labels to delete what follows. */
1305 else if (code == CODE_LABEL && INSN_DELETED_P (next))
1306 next = NEXT_INSN (next);
1307 else if (code == BARRIER || INSN_P (next))
1308 /* Note: if this deletes a jump, it can cause more
1309 deletion of unreachable code, after a different label.
1310 As long as the value from this recursive call is correct,
1311 this invocation functions correctly. */
1312 next = delete_related_insns (next);
1318 /* I feel a little doubtful about this loop,
1319 but I see no clean and sure alternative way
1320 to find the first insn after INSN that is not now deleted.
1321 I hope this works. */
1322 while (next && INSN_DELETED_P (next))
1323 next = NEXT_INSN (next);
1327 /* Delete a range of insns from FROM to TO, inclusive.
1328 This is for the sake of peephole optimization, so assume
1329 that whatever these insns do will still be done by a new
1330 peephole insn that will replace them. */
1333 delete_for_peephole (rtx from, rtx to)
1339 rtx next = NEXT_INSN (insn);
1340 rtx prev = PREV_INSN (insn);
1344 INSN_DELETED_P (insn) = 1;
1346 /* Patch this insn out of the chain. */
1347 /* We don't do this all at once, because we
1348 must preserve all NOTEs. */
1350 NEXT_INSN (prev) = next;
1353 PREV_INSN (next) = prev;
1361 /* Note that if TO is an unconditional jump
1362 we *do not* delete the BARRIER that follows,
1363 since the peephole that replaces this sequence
1364 is also an unconditional jump in that case. */
1367 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
1368 NLABEL as a return. Accrue modifications into the change group. */
1371 redirect_exp_1 (rtx *loc, rtx olabel, rtx nlabel, rtx insn)
1374 RTX_CODE code = GET_CODE (x);
1378 if (code == LABEL_REF)
1380 if (XEXP (x, 0) == olabel)
1384 n = gen_rtx_LABEL_REF (Pmode, nlabel);
1388 validate_change (insn, loc, n, 1);
1392 else if (code == RETURN && olabel == 0)
1395 x = gen_rtx_LABEL_REF (Pmode, nlabel);
1398 if (loc == &PATTERN (insn))
1399 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
1400 validate_change (insn, loc, x, 1);
1404 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
1405 && GET_CODE (SET_SRC (x)) == LABEL_REF
1406 && XEXP (SET_SRC (x), 0) == olabel)
1408 validate_change (insn, loc, ret_rtx, 1);
1412 if (code == IF_THEN_ELSE)
1414 /* Skip the condition of an IF_THEN_ELSE. We only want to
1415 change jump destinations, not eventual label comparisons. */
1416 redirect_exp_1 (&XEXP (x, 1), olabel, nlabel, insn);
1417 redirect_exp_1 (&XEXP (x, 2), olabel, nlabel, insn);
1421 fmt = GET_RTX_FORMAT (code);
1422 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1425 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
1426 else if (fmt[i] == 'E')
1429 for (j = 0; j < XVECLEN (x, i); j++)
1430 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
1435 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
1436 the modifications into the change group. Return false if we did
1437 not see how to do that. */
1440 redirect_jump_1 (rtx jump, rtx nlabel)
1442 int ochanges = num_validated_changes ();
1445 asmop = extract_asm_operands (PATTERN (jump));
1450 gcc_assert (ASM_OPERANDS_LABEL_LENGTH (asmop) == 1);
1451 loc = &ASM_OPERANDS_LABEL (asmop, 0);
1453 else if (GET_CODE (PATTERN (jump)) == PARALLEL)
1454 loc = &XVECEXP (PATTERN (jump), 0, 0);
1456 loc = &PATTERN (jump);
1458 redirect_exp_1 (loc, JUMP_LABEL (jump), nlabel, jump);
1459 return num_validated_changes () > ochanges;
1462 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
1463 jump target label is unused as a result, it and the code following
1466 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
1469 The return value will be 1 if the change was made, 0 if it wasn't
1470 (this can only occur for NLABEL == 0). */
1473 redirect_jump (rtx jump, rtx nlabel, int delete_unused)
1475 rtx olabel = JUMP_LABEL (jump);
1477 if (nlabel == olabel)
1480 if (! redirect_jump_1 (jump, nlabel) || ! apply_change_group ())
1483 redirect_jump_2 (jump, olabel, nlabel, delete_unused, 0);
1487 /* Fix up JUMP_LABEL and label ref counts after OLABEL has been replaced with
1489 If DELETE_UNUSED is positive, delete related insn to OLABEL if its ref
1490 count has dropped to zero. */
1492 redirect_jump_2 (rtx jump, rtx olabel, rtx nlabel, int delete_unused,
1497 gcc_assert (JUMP_LABEL (jump) == olabel);
1499 /* Negative DELETE_UNUSED used to be used to signalize behavior on
1500 moving FUNCTION_END note. Just sanity check that no user still worry
1502 gcc_assert (delete_unused >= 0);
1503 JUMP_LABEL (jump) = nlabel;
1505 ++LABEL_NUSES (nlabel);
1507 /* Update labels in any REG_EQUAL note. */
1508 if ((note = find_reg_note (jump, REG_EQUAL, NULL_RTX)) != NULL_RTX)
1510 if (!nlabel || (invert && !invert_exp_1 (XEXP (note, 0), jump)))
1511 remove_note (jump, note);
1514 redirect_exp_1 (&XEXP (note, 0), olabel, nlabel, jump);
1515 confirm_change_group ();
1519 if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused > 0
1520 /* Undefined labels will remain outside the insn stream. */
1521 && INSN_UID (olabel))
1522 delete_related_insns (olabel);
1524 invert_br_probabilities (jump);
1527 /* Invert the jump condition X contained in jump insn INSN. Accrue the
1528 modifications into the change group. Return nonzero for success. */
1530 invert_exp_1 (rtx x, rtx insn)
1532 RTX_CODE code = GET_CODE (x);
1534 if (code == IF_THEN_ELSE)
1536 rtx comp = XEXP (x, 0);
1538 enum rtx_code reversed_code;
1540 /* We can do this in two ways: The preferable way, which can only
1541 be done if this is not an integer comparison, is to reverse
1542 the comparison code. Otherwise, swap the THEN-part and ELSE-part
1543 of the IF_THEN_ELSE. If we can't do either, fail. */
1545 reversed_code = reversed_comparison_code (comp, insn);
1547 if (reversed_code != UNKNOWN)
1549 validate_change (insn, &XEXP (x, 0),
1550 gen_rtx_fmt_ee (reversed_code,
1551 GET_MODE (comp), XEXP (comp, 0),
1558 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
1559 validate_change (insn, &XEXP (x, 2), tem, 1);
1566 /* Invert the condition of the jump JUMP, and make it jump to label
1567 NLABEL instead of where it jumps now. Accrue changes into the
1568 change group. Return false if we didn't see how to perform the
1569 inversion and redirection. */
1572 invert_jump_1 (rtx jump, rtx nlabel)
1574 rtx x = pc_set (jump);
1578 ochanges = num_validated_changes ();
1581 ok = invert_exp_1 (SET_SRC (x), jump);
1584 if (num_validated_changes () == ochanges)
1587 /* redirect_jump_1 will fail of nlabel == olabel, and the current use is
1588 in Pmode, so checking this is not merely an optimization. */
1589 return nlabel == JUMP_LABEL (jump) || redirect_jump_1 (jump, nlabel);
1592 /* Invert the condition of the jump JUMP, and make it jump to label
1593 NLABEL instead of where it jumps now. Return true if successful. */
1596 invert_jump (rtx jump, rtx nlabel, int delete_unused)
1598 rtx olabel = JUMP_LABEL (jump);
1600 if (invert_jump_1 (jump, nlabel) && apply_change_group ())
1602 redirect_jump_2 (jump, olabel, nlabel, delete_unused, 1);
1610 /* Like rtx_equal_p except that it considers two REGs as equal
1611 if they renumber to the same value and considers two commutative
1612 operations to be the same if the order of the operands has been
1616 rtx_renumbered_equal_p (const_rtx x, const_rtx y)
1619 const enum rtx_code code = GET_CODE (x);
1625 if ((code == REG || (code == SUBREG && REG_P (SUBREG_REG (x))))
1626 && (REG_P (y) || (GET_CODE (y) == SUBREG
1627 && REG_P (SUBREG_REG (y)))))
1629 int reg_x = -1, reg_y = -1;
1630 int byte_x = 0, byte_y = 0;
1631 struct subreg_info info;
1633 if (GET_MODE (x) != GET_MODE (y))
1636 /* If we haven't done any renumbering, don't
1637 make any assumptions. */
1638 if (reg_renumber == 0)
1639 return rtx_equal_p (x, y);
1643 reg_x = REGNO (SUBREG_REG (x));
1644 byte_x = SUBREG_BYTE (x);
1646 if (reg_renumber[reg_x] >= 0)
1648 subreg_get_info (reg_renumber[reg_x],
1649 GET_MODE (SUBREG_REG (x)), byte_x,
1650 GET_MODE (x), &info);
1651 if (!info.representable_p)
1653 reg_x = info.offset;
1660 if (reg_renumber[reg_x] >= 0)
1661 reg_x = reg_renumber[reg_x];
1664 if (GET_CODE (y) == SUBREG)
1666 reg_y = REGNO (SUBREG_REG (y));
1667 byte_y = SUBREG_BYTE (y);
1669 if (reg_renumber[reg_y] >= 0)
1671 subreg_get_info (reg_renumber[reg_y],
1672 GET_MODE (SUBREG_REG (y)), byte_y,
1673 GET_MODE (y), &info);
1674 if (!info.representable_p)
1676 reg_y = info.offset;
1683 if (reg_renumber[reg_y] >= 0)
1684 reg_y = reg_renumber[reg_y];
1687 return reg_x >= 0 && reg_x == reg_y && byte_x == byte_y;
1690 /* Now we have disposed of all the cases
1691 in which different rtx codes can match. */
1692 if (code != GET_CODE (y))
1706 /* We can't assume nonlocal labels have their following insns yet. */
1707 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
1708 return XEXP (x, 0) == XEXP (y, 0);
1710 /* Two label-refs are equivalent if they point at labels
1711 in the same position in the instruction stream. */
1712 return (next_real_insn (XEXP (x, 0))
1713 == next_real_insn (XEXP (y, 0)));
1716 return XSTR (x, 0) == XSTR (y, 0);
1719 /* If we didn't match EQ equality above, they aren't the same. */
1726 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
1728 if (GET_MODE (x) != GET_MODE (y))
1731 /* MEMs refering to different address space are not equivalent. */
1732 if (code == MEM && MEM_ADDR_SPACE (x) != MEM_ADDR_SPACE (y))
1735 /* For commutative operations, the RTX match if the operand match in any
1736 order. Also handle the simple binary and unary cases without a loop. */
1737 if (targetm.commutative_p (x, UNKNOWN))
1738 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
1739 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
1740 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
1741 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
1742 else if (NON_COMMUTATIVE_P (x))
1743 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
1744 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
1745 else if (UNARY_P (x))
1746 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
1748 /* Compare the elements. If any pair of corresponding elements
1749 fail to match, return 0 for the whole things. */
1751 fmt = GET_RTX_FORMAT (code);
1752 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1758 if (XWINT (x, i) != XWINT (y, i))
1763 if (XINT (x, i) != XINT (y, i))
1765 if (((code == ASM_OPERANDS && i == 6)
1766 || (code == ASM_INPUT && i == 1))
1767 && locator_eq (XINT (x, i), XINT (y, i)))
1774 if (XTREE (x, i) != XTREE (y, i))
1779 if (strcmp (XSTR (x, i), XSTR (y, i)))
1784 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
1789 if (XEXP (x, i) != XEXP (y, i))
1796 if (XVECLEN (x, i) != XVECLEN (y, i))
1798 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
1799 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
1810 /* If X is a hard register or equivalent to one or a subregister of one,
1811 return the hard register number. If X is a pseudo register that was not
1812 assigned a hard register, return the pseudo register number. Otherwise,
1813 return -1. Any rtx is valid for X. */
1816 true_regnum (const_rtx x)
1820 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
1821 return reg_renumber[REGNO (x)];
1824 if (GET_CODE (x) == SUBREG)
1826 int base = true_regnum (SUBREG_REG (x));
1828 && base < FIRST_PSEUDO_REGISTER)
1830 struct subreg_info info;
1832 subreg_get_info (REGNO (SUBREG_REG (x)),
1833 GET_MODE (SUBREG_REG (x)),
1834 SUBREG_BYTE (x), GET_MODE (x), &info);
1836 if (info.representable_p)
1837 return base + info.offset;
1843 /* Return regno of the register REG and handle subregs too. */
1845 reg_or_subregno (const_rtx reg)
1847 if (GET_CODE (reg) == SUBREG)
1848 reg = SUBREG_REG (reg);
1849 gcc_assert (REG_P (reg));