1 /* Analyze RTL for C-Compiler
2 Copyright (C) 1987, 88, 92-97, 1998 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
26 static int rtx_addr_can_trap_p
PROTO((rtx
));
27 static void reg_set_p_1
PROTO((rtx
, rtx
));
28 static void reg_set_last_1
PROTO((rtx
, rtx
));
31 /* Forward declarations */
32 static int jmp_uses_reg_or_mem
PROTO((rtx
));
34 /* Bit flags that specify the machine subtype we are compiling for.
35 Bits are tested using macros TARGET_... defined in the tm.h file
36 and set by `-m...' switches. Must be defined in rtlanal.c. */
40 /* Return 1 if the value of X is unstable
41 (would be different at a different point in the program).
42 The frame pointer, arg pointer, etc. are considered stable
43 (within one function) and so is anything marked `unchanging'. */
49 register RTX_CODE code
= GET_CODE (x
);
54 return ! RTX_UNCHANGING_P (x
);
59 if (code
== CONST
|| code
== CONST_INT
)
63 return ! (REGNO (x
) == FRAME_POINTER_REGNUM
64 || REGNO (x
) == HARD_FRAME_POINTER_REGNUM
65 || REGNO (x
) == ARG_POINTER_REGNUM
66 || RTX_UNCHANGING_P (x
));
68 fmt
= GET_RTX_FORMAT (code
);
69 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
71 if (rtx_unstable_p (XEXP (x
, i
)))
76 /* Return 1 if X has a value that can vary even between two
77 executions of the program. 0 means X can be compared reliably
78 against certain constants or near-constants.
79 The frame pointer and the arg pointer are considered constant. */
85 register RTX_CODE code
= GET_CODE (x
);
103 /* Note that we have to test for the actual rtx used for the frame
104 and arg pointers and not just the register number in case we have
105 eliminated the frame and/or arg pointer and are using it
107 return ! (x
== frame_pointer_rtx
|| x
== hard_frame_pointer_rtx
108 || x
== arg_pointer_rtx
|| x
== pic_offset_table_rtx
);
111 /* The operand 0 of a LO_SUM is considered constant
112 (in fact is it related specifically to operand 1). */
113 return rtx_varies_p (XEXP (x
, 1));
119 fmt
= GET_RTX_FORMAT (code
);
120 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
122 if (rtx_varies_p (XEXP (x
, i
)))
127 /* Return 0 if the use of X as an address in a MEM can cause a trap. */
130 rtx_addr_can_trap_p (x
)
133 register enum rtx_code code
= GET_CODE (x
);
139 /* SYMBOL_REF is problematic due to the possible presence of
140 a #pragma weak, but to say that loads from symbols can trap is
141 *very* costly. It's not at all clear what's best here. For
142 now, we ignore the impact of #pragma weak. */
146 /* As in rtx_varies_p, we have to use the actual rtx, not reg number. */
147 return ! (x
== frame_pointer_rtx
|| x
== hard_frame_pointer_rtx
148 || x
== stack_pointer_rtx
|| x
== arg_pointer_rtx
);
151 return rtx_addr_can_trap_p (XEXP (x
, 0));
154 /* An address is assumed not to trap if it is an address that can't
155 trap plus a constant integer. */
156 return (rtx_addr_can_trap_p (XEXP (x
, 0))
157 || GET_CODE (XEXP (x
, 1)) != CONST_INT
);
160 return rtx_addr_can_trap_p (XEXP (x
, 1));
166 /* If it isn't one of the case above, it can cause a trap. */
170 /* Return 1 if X refers to a memory location whose address
171 cannot be compared reliably with constant addresses,
172 or if X refers to a BLKmode memory object. */
175 rtx_addr_varies_p (x
)
178 register enum rtx_code code
;
187 return GET_MODE (x
) == BLKmode
|| rtx_varies_p (XEXP (x
, 0));
189 fmt
= GET_RTX_FORMAT (code
);
190 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
193 if (rtx_addr_varies_p (XEXP (x
, i
)))
196 else if (fmt
[i
] == 'E')
199 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
200 if (rtx_addr_varies_p (XVECEXP (x
, i
, j
)))
206 /* Return the value of the integer term in X, if one is apparent;
208 Only obvious integer terms are detected.
209 This is used in cse.c with the `related_value' field.*/
215 if (GET_CODE (x
) == CONST
)
218 if (GET_CODE (x
) == MINUS
219 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
220 return - INTVAL (XEXP (x
, 1));
221 if (GET_CODE (x
) == PLUS
222 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
223 return INTVAL (XEXP (x
, 1));
227 /* If X is a constant, return the value sans apparent integer term;
229 Only obvious integer terms are detected. */
232 get_related_value (x
)
235 if (GET_CODE (x
) != CONST
)
238 if (GET_CODE (x
) == PLUS
239 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
241 else if (GET_CODE (x
) == MINUS
242 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
247 /* Nonzero if register REG appears somewhere within IN.
248 Also works if REG is not a register; in this case it checks
249 for a subexpression of IN that is Lisp "equal" to REG. */
252 reg_mentioned_p (reg
, in
)
253 register rtx reg
, in
;
257 register enum rtx_code code
;
265 if (GET_CODE (in
) == LABEL_REF
)
266 return reg
== XEXP (in
, 0);
268 code
= GET_CODE (in
);
272 /* Compare registers by number. */
274 return GET_CODE (reg
) == REG
&& REGNO (in
) == REGNO (reg
);
276 /* These codes have no constituent expressions
284 return GET_CODE (reg
) == CONST_INT
&& INTVAL (in
) == INTVAL (reg
);
287 /* These are kept unique for a given value. */
294 if (GET_CODE (reg
) == code
&& rtx_equal_p (reg
, in
))
297 fmt
= GET_RTX_FORMAT (code
);
299 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
304 for (j
= XVECLEN (in
, i
) - 1; j
>= 0; j
--)
305 if (reg_mentioned_p (reg
, XVECEXP (in
, i
, j
)))
308 else if (fmt
[i
] == 'e'
309 && reg_mentioned_p (reg
, XEXP (in
, i
)))
315 /* Return 1 if in between BEG and END, exclusive of BEG and END, there is
316 no CODE_LABEL insn. */
319 no_labels_between_p (beg
, end
)
323 for (p
= NEXT_INSN (beg
); p
!= end
; p
= NEXT_INSN (p
))
324 if (GET_CODE (p
) == CODE_LABEL
)
329 /* Nonzero if register REG is used in an insn between
330 FROM_INSN and TO_INSN (exclusive of those two). */
333 reg_used_between_p (reg
, from_insn
, to_insn
)
334 rtx reg
, from_insn
, to_insn
;
338 if (from_insn
== to_insn
)
341 for (insn
= NEXT_INSN (from_insn
); insn
!= to_insn
; insn
= NEXT_INSN (insn
))
342 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
343 && (reg_overlap_mentioned_p (reg
, PATTERN (insn
))
344 || (GET_CODE (insn
) == CALL_INSN
345 && (find_reg_fusage (insn
, USE
, reg
)
346 || find_reg_fusage (insn
, CLOBBER
, reg
)))))
351 /* Nonzero if the old value of X, a register, is referenced in BODY. If X
352 is entirely replaced by a new value and the only use is as a SET_DEST,
353 we do not consider it a reference. */
356 reg_referenced_p (x
, body
)
362 switch (GET_CODE (body
))
365 if (reg_overlap_mentioned_p (x
, SET_SRC (body
)))
368 /* If the destination is anything other than CC0, PC, a REG or a SUBREG
369 of a REG that occupies all of the REG, the insn references X if
370 it is mentioned in the destination. */
371 if (GET_CODE (SET_DEST (body
)) != CC0
372 && GET_CODE (SET_DEST (body
)) != PC
373 && GET_CODE (SET_DEST (body
)) != REG
374 && ! (GET_CODE (SET_DEST (body
)) == SUBREG
375 && GET_CODE (SUBREG_REG (SET_DEST (body
))) == REG
376 && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (body
))))
377 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)
378 == ((GET_MODE_SIZE (GET_MODE (SET_DEST (body
)))
379 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)))
380 && reg_overlap_mentioned_p (x
, SET_DEST (body
)))
385 for (i
= ASM_OPERANDS_INPUT_LENGTH (body
) - 1; i
>= 0; i
--)
386 if (reg_overlap_mentioned_p (x
, ASM_OPERANDS_INPUT (body
, i
)))
392 return reg_overlap_mentioned_p (x
, body
);
395 return reg_overlap_mentioned_p (x
, TRAP_CONDITION (body
));
398 case UNSPEC_VOLATILE
:
400 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; i
--)
401 if (reg_referenced_p (x
, XVECEXP (body
, 0, i
)))
410 /* Nonzero if register REG is referenced in an insn between
411 FROM_INSN and TO_INSN (exclusive of those two). Sets of REG do
415 reg_referenced_between_p (reg
, from_insn
, to_insn
)
416 rtx reg
, from_insn
, to_insn
;
420 if (from_insn
== to_insn
)
423 for (insn
= NEXT_INSN (from_insn
); insn
!= to_insn
; insn
= NEXT_INSN (insn
))
424 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
425 && (reg_referenced_p (reg
, PATTERN (insn
))
426 || (GET_CODE (insn
) == CALL_INSN
427 && find_reg_fusage (insn
, USE
, reg
))))
432 /* Nonzero if register REG is set or clobbered in an insn between
433 FROM_INSN and TO_INSN (exclusive of those two). */
436 reg_set_between_p (reg
, from_insn
, to_insn
)
437 rtx reg
, from_insn
, to_insn
;
441 if (from_insn
== to_insn
)
444 for (insn
= NEXT_INSN (from_insn
); insn
!= to_insn
; insn
= NEXT_INSN (insn
))
445 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
446 && reg_set_p (reg
, insn
))
451 /* Internals of reg_set_between_p. */
453 static rtx reg_set_reg
;
454 static int reg_set_flag
;
459 rtx pat ATTRIBUTE_UNUSED
;
461 /* We don't want to return 1 if X is a MEM that contains a register
462 within REG_SET_REG. */
464 if ((GET_CODE (x
) != MEM
)
465 && reg_overlap_mentioned_p (reg_set_reg
, x
))
470 reg_set_p (reg
, insn
)
475 /* We can be passed an insn or part of one. If we are passed an insn,
476 check if a side-effect of the insn clobbers REG. */
477 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
479 if (FIND_REG_INC_NOTE (insn
, reg
)
480 || (GET_CODE (insn
) == CALL_INSN
481 /* We'd like to test call_used_regs here, but rtlanal.c can't
482 reference that variable due to its use in genattrtab. So
483 we'll just be more conservative.
485 ??? Unless we could ensure that the CALL_INSN_FUNCTION_USAGE
486 information holds all clobbered registers. */
487 && ((GET_CODE (reg
) == REG
488 && REGNO (reg
) < FIRST_PSEUDO_REGISTER
)
489 || GET_CODE (reg
) == MEM
490 || find_reg_fusage (insn
, CLOBBER
, reg
))))
493 body
= PATTERN (insn
);
498 note_stores (body
, reg_set_p_1
);
502 /* Similar to reg_set_between_p, but check all registers in X. Return 0
503 only if none of them are modified between START and END. Return 1 if
504 X contains a MEM; this routine does not perform any memory aliasing. */
507 modified_between_p (x
, start
, end
)
511 enum rtx_code code
= GET_CODE (x
);
529 /* If the memory is not constant, assume it is modified. If it is
530 constant, we still have to check the address. */
531 if (! RTX_UNCHANGING_P (x
))
536 return reg_set_between_p (x
, start
, end
);
542 fmt
= GET_RTX_FORMAT (code
);
543 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
545 if (fmt
[i
] == 'e' && modified_between_p (XEXP (x
, i
), start
, end
))
549 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
550 if (modified_between_p (XVECEXP (x
, i
, j
), start
, end
))
557 /* Similar to reg_set_p, but check all registers in X. Return 0 only if none
558 of them are modified in INSN. Return 1 if X contains a MEM; this routine
559 does not perform any memory aliasing. */
562 modified_in_p (x
, insn
)
566 enum rtx_code code
= GET_CODE (x
);
584 /* If the memory is not constant, assume it is modified. If it is
585 constant, we still have to check the address. */
586 if (! RTX_UNCHANGING_P (x
))
591 return reg_set_p (x
, insn
);
597 fmt
= GET_RTX_FORMAT (code
);
598 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
600 if (fmt
[i
] == 'e' && modified_in_p (XEXP (x
, i
), insn
))
604 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
605 if (modified_in_p (XVECEXP (x
, i
, j
), insn
))
612 /* Given an INSN, return a SET expression if this insn has only a single SET.
613 It may also have CLOBBERs, USEs, or SET whose output
614 will not be used, which we ignore. */
623 if (GET_RTX_CLASS (GET_CODE (insn
)) != 'i')
626 if (GET_CODE (PATTERN (insn
)) == SET
)
627 return PATTERN (insn
);
629 else if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
631 for (i
= 0, set
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
632 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, i
)) == SET
633 && (! find_reg_note (insn
, REG_UNUSED
,
634 SET_DEST (XVECEXP (PATTERN (insn
), 0, i
)))
635 || side_effects_p (XVECEXP (PATTERN (insn
), 0, i
))))
640 set
= XVECEXP (PATTERN (insn
), 0, i
);
648 /* Return the last thing that X was assigned from before *PINSN. Verify that
649 the object is not modified up to VALID_TO. If it was, if we hit
650 a partial assignment to X, or hit a CODE_LABEL first, return X. If we
651 found an assignment, update *PINSN to point to it. */
654 find_last_value (x
, pinsn
, valid_to
)
661 for (p
= PREV_INSN (*pinsn
); p
&& GET_CODE (p
) != CODE_LABEL
;
663 if (GET_RTX_CLASS (GET_CODE (p
)) == 'i')
665 rtx set
= single_set (p
);
666 rtx note
= find_reg_note (p
, REG_EQUAL
, NULL_RTX
);
668 if (set
&& rtx_equal_p (x
, SET_DEST (set
)))
670 rtx src
= SET_SRC (set
);
672 if (note
&& GET_CODE (XEXP (note
, 0)) != EXPR_LIST
)
673 src
= XEXP (note
, 0);
675 if (! modified_between_p (src
, PREV_INSN (p
), valid_to
)
676 /* Reject hard registers because we don't usually want
677 to use them; we'd rather use a pseudo. */
678 && ! (GET_CODE (src
) == REG
679 && REGNO (src
) < FIRST_PSEUDO_REGISTER
))
686 /* If set in non-simple way, we don't have a value. */
687 if (reg_set_p (x
, p
))
694 /* Return nonzero if register in range [REGNO, ENDREGNO)
695 appears either explicitly or implicitly in X
696 other than being stored into.
698 References contained within the substructure at LOC do not count.
699 LOC may be zero, meaning don't ignore anything. */
702 refers_to_regno_p (regno
, endregno
, x
, loc
)
708 register RTX_CODE code
;
712 /* The contents of a REG_NONNEG note is always zero, so we must come here
713 upon repeat in case the last REG_NOTE is a REG_NONNEG note. */
724 /* If we modifying the stack, frame, or argument pointer, it will
725 clobber a virtual register. In fact, we could be more precise,
726 but it isn't worth it. */
727 if ((i
== STACK_POINTER_REGNUM
728 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
729 || i
== ARG_POINTER_REGNUM
731 || i
== FRAME_POINTER_REGNUM
)
732 && regno
>= FIRST_VIRTUAL_REGISTER
&& regno
<= LAST_VIRTUAL_REGISTER
)
736 && regno
< i
+ (i
< FIRST_PSEUDO_REGISTER
737 ? HARD_REGNO_NREGS (i
, GET_MODE (x
))
741 /* If this is a SUBREG of a hard reg, we can see exactly which
742 registers are being modified. Otherwise, handle normally. */
743 if (GET_CODE (SUBREG_REG (x
)) == REG
744 && REGNO (SUBREG_REG (x
)) < FIRST_PSEUDO_REGISTER
)
746 int inner_regno
= REGNO (SUBREG_REG (x
)) + SUBREG_WORD (x
);
748 = inner_regno
+ (inner_regno
< FIRST_PSEUDO_REGISTER
749 ? HARD_REGNO_NREGS (regno
, GET_MODE (x
)) : 1);
751 return endregno
> inner_regno
&& regno
< inner_endregno
;
757 if (&SET_DEST (x
) != loc
758 /* Note setting a SUBREG counts as referring to the REG it is in for
759 a pseudo but not for hard registers since we can
760 treat each word individually. */
761 && ((GET_CODE (SET_DEST (x
)) == SUBREG
762 && loc
!= &SUBREG_REG (SET_DEST (x
))
763 && GET_CODE (SUBREG_REG (SET_DEST (x
))) == REG
764 && REGNO (SUBREG_REG (SET_DEST (x
))) >= FIRST_PSEUDO_REGISTER
765 && refers_to_regno_p (regno
, endregno
,
766 SUBREG_REG (SET_DEST (x
)), loc
))
767 || (GET_CODE (SET_DEST (x
)) != REG
768 && refers_to_regno_p (regno
, endregno
, SET_DEST (x
), loc
))))
771 if (code
== CLOBBER
|| loc
== &SET_SRC (x
))
780 /* X does not match, so try its subexpressions. */
782 fmt
= GET_RTX_FORMAT (code
);
783 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
785 if (fmt
[i
] == 'e' && loc
!= &XEXP (x
, i
))
793 if (refers_to_regno_p (regno
, endregno
, XEXP (x
, i
), loc
))
796 else if (fmt
[i
] == 'E')
799 for (j
= XVECLEN (x
, i
) - 1; j
>=0; j
--)
800 if (loc
!= &XVECEXP (x
, i
, j
)
801 && refers_to_regno_p (regno
, endregno
, XVECEXP (x
, i
, j
), loc
))
808 /* Nonzero if modifying X will affect IN. If X is a register or a SUBREG,
809 we check if any register number in X conflicts with the relevant register
810 numbers. If X is a constant, return 0. If X is a MEM, return 1 iff IN
811 contains a MEM (we don't bother checking for memory addresses that can't
812 conflict because we expect this to be a rare case. */
815 reg_overlap_mentioned_p (x
, in
)
820 if (GET_CODE (x
) == SUBREG
)
822 regno
= REGNO (SUBREG_REG (x
));
823 if (regno
< FIRST_PSEUDO_REGISTER
)
824 regno
+= SUBREG_WORD (x
);
826 else if (GET_CODE (x
) == REG
)
828 else if (CONSTANT_P (x
))
830 else if (GET_CODE (x
) == MEM
)
835 if (GET_CODE (in
) == MEM
)
838 fmt
= GET_RTX_FORMAT (GET_CODE (in
));
840 for (i
= GET_RTX_LENGTH (GET_CODE (in
)) - 1; i
>= 0; i
--)
841 if (fmt
[i
] == 'e' && reg_overlap_mentioned_p (x
, XEXP (in
, i
)))
846 else if (GET_CODE (x
) == SCRATCH
|| GET_CODE (x
) == PC
847 || GET_CODE (x
) == CC0
)
848 return reg_mentioned_p (x
, in
);
852 endregno
= regno
+ (regno
< FIRST_PSEUDO_REGISTER
853 ? HARD_REGNO_NREGS (regno
, GET_MODE (x
)) : 1);
855 return refers_to_regno_p (regno
, endregno
, in
, NULL_PTR
);
858 /* Used for communications between the next few functions. */
860 static int reg_set_last_unknown
;
861 static rtx reg_set_last_value
;
862 static int reg_set_last_first_regno
, reg_set_last_last_regno
;
864 /* Called via note_stores from reg_set_last. */
867 reg_set_last_1 (x
, pat
)
873 /* If X is not a register, or is not one in the range we care
875 if (GET_CODE (x
) != REG
)
879 last
= first
+ (first
< FIRST_PSEUDO_REGISTER
880 ? HARD_REGNO_NREGS (first
, GET_MODE (x
)) : 1);
882 if (first
>= reg_set_last_last_regno
883 || last
<= reg_set_last_first_regno
)
886 /* If this is a CLOBBER or is some complex LHS, or doesn't modify
887 exactly the registers we care about, show we don't know the value. */
888 if (GET_CODE (pat
) == CLOBBER
|| SET_DEST (pat
) != x
889 || first
!= reg_set_last_first_regno
890 || last
!= reg_set_last_last_regno
)
891 reg_set_last_unknown
= 1;
893 reg_set_last_value
= SET_SRC (pat
);
896 /* Return the last value to which REG was set prior to INSN. If we can't
897 find it easily, return 0.
899 We only return a REG, SUBREG, or constant because it is too hard to
900 check if a MEM remains unchanged. */
903 reg_set_last (x
, insn
)
907 rtx orig_insn
= insn
;
909 reg_set_last_first_regno
= REGNO (x
);
911 reg_set_last_last_regno
912 = reg_set_last_first_regno
913 + (reg_set_last_first_regno
< FIRST_PSEUDO_REGISTER
914 ? HARD_REGNO_NREGS (reg_set_last_first_regno
, GET_MODE (x
)) : 1);
916 reg_set_last_unknown
= 0;
917 reg_set_last_value
= 0;
919 /* Scan backwards until reg_set_last_1 changed one of the above flags.
920 Stop when we reach a label or X is a hard reg and we reach a
921 CALL_INSN (if reg_set_last_last_regno is a hard reg).
923 If we find a set of X, ensure that its SET_SRC remains unchanged. */
925 /* We compare with <= here, because reg_set_last_last_regno
926 is actually the number of the first reg *not* in X. */
928 insn
&& GET_CODE (insn
) != CODE_LABEL
929 && ! (GET_CODE (insn
) == CALL_INSN
930 && reg_set_last_last_regno
<= FIRST_PSEUDO_REGISTER
);
931 insn
= PREV_INSN (insn
))
932 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
934 note_stores (PATTERN (insn
), reg_set_last_1
);
935 if (reg_set_last_unknown
)
937 else if (reg_set_last_value
)
939 if (CONSTANT_P (reg_set_last_value
)
940 || ((GET_CODE (reg_set_last_value
) == REG
941 || GET_CODE (reg_set_last_value
) == SUBREG
)
942 && ! reg_set_between_p (reg_set_last_value
,
944 return reg_set_last_value
;
953 /* This is 1 until after the rtl generation pass. */
954 int rtx_equal_function_value_matters
;
956 /* Return 1 if X and Y are identical-looking rtx's.
957 This is the Lisp function EQUAL for rtx arguments. */
965 register enum rtx_code code
;
970 if (x
== 0 || y
== 0)
974 /* Rtx's of different codes cannot be equal. */
975 if (code
!= GET_CODE (y
))
978 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
979 (REG:SI x) and (REG:HI x) are NOT equivalent. */
981 if (GET_MODE (x
) != GET_MODE (y
))
984 /* REG, LABEL_REF, and SYMBOL_REF can be compared nonrecursively. */
987 /* Until rtl generation is complete, don't consider a reference to the
988 return register of the current function the same as the return from a
989 called function. This eases the job of function integration. Once the
990 distinction is no longer needed, they can be considered equivalent. */
991 return (REGNO (x
) == REGNO (y
)
992 && (! rtx_equal_function_value_matters
993 || REG_FUNCTION_VALUE_P (x
) == REG_FUNCTION_VALUE_P (y
)));
994 else if (code
== LABEL_REF
)
995 return XEXP (x
, 0) == XEXP (y
, 0);
996 else if (code
== SYMBOL_REF
)
997 return XSTR (x
, 0) == XSTR (y
, 0);
998 else if (code
== SCRATCH
|| code
== CONST_DOUBLE
)
1001 /* Compare the elements. If any pair of corresponding elements
1002 fail to match, return 0 for the whole things. */
1004 fmt
= GET_RTX_FORMAT (code
);
1005 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1010 if (XWINT (x
, i
) != XWINT (y
, i
))
1016 if (XINT (x
, i
) != XINT (y
, i
))
1022 /* Two vectors must have the same length. */
1023 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
1026 /* And the corresponding elements must match. */
1027 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1028 if (rtx_equal_p (XVECEXP (x
, i
, j
), XVECEXP (y
, i
, j
)) == 0)
1033 if (rtx_equal_p (XEXP (x
, i
), XEXP (y
, i
)) == 0)
1039 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
1044 /* These are just backpointers, so they don't matter. */
1050 /* It is believed that rtx's at this level will never
1051 contain anything but integers and other rtx's,
1052 except for within LABEL_REFs and SYMBOL_REFs. */
1060 /* Call FUN on each register or MEM that is stored into or clobbered by X.
1061 (X would be the pattern of an insn).
1062 FUN receives two arguments:
1063 the REG, MEM, CC0 or PC being stored in or clobbered,
1064 the SET or CLOBBER rtx that does the store.
1066 If the item being stored in or clobbered is a SUBREG of a hard register,
1067 the SUBREG will be passed. */
1070 note_stores (x
, fun
)
1074 if ((GET_CODE (x
) == SET
|| GET_CODE (x
) == CLOBBER
))
1076 register rtx dest
= SET_DEST (x
);
1077 while ((GET_CODE (dest
) == SUBREG
1078 && (GET_CODE (SUBREG_REG (dest
)) != REG
1079 || REGNO (SUBREG_REG (dest
)) >= FIRST_PSEUDO_REGISTER
))
1080 || GET_CODE (dest
) == ZERO_EXTRACT
1081 || GET_CODE (dest
) == SIGN_EXTRACT
1082 || GET_CODE (dest
) == STRICT_LOW_PART
)
1083 dest
= XEXP (dest
, 0);
1086 else if (GET_CODE (x
) == PARALLEL
)
1089 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
1091 register rtx y
= XVECEXP (x
, 0, i
);
1092 if (GET_CODE (y
) == SET
|| GET_CODE (y
) == CLOBBER
)
1094 register rtx dest
= SET_DEST (y
);
1095 while ((GET_CODE (dest
) == SUBREG
1096 && (GET_CODE (SUBREG_REG (dest
)) != REG
1097 || (REGNO (SUBREG_REG (dest
))
1098 >= FIRST_PSEUDO_REGISTER
)))
1099 || GET_CODE (dest
) == ZERO_EXTRACT
1100 || GET_CODE (dest
) == SIGN_EXTRACT
1101 || GET_CODE (dest
) == STRICT_LOW_PART
)
1102 dest
= XEXP (dest
, 0);
1109 /* Return nonzero if X's old contents don't survive after INSN.
1110 This will be true if X is (cc0) or if X is a register and
1111 X dies in INSN or because INSN entirely sets X.
1113 "Entirely set" means set directly and not through a SUBREG,
1114 ZERO_EXTRACT or SIGN_EXTRACT, so no trace of the old contents remains.
1115 Likewise, REG_INC does not count.
1117 REG may be a hard or pseudo reg. Renumbering is not taken into account,
1118 but for this use that makes no difference, since regs don't overlap
1119 during their lifetimes. Therefore, this function may be used
1120 at any time after deaths have been computed (in flow.c).
1122 If REG is a hard reg that occupies multiple machine registers, this
1123 function will only return 1 if each of those registers will be replaced
1127 dead_or_set_p (insn
, x
)
1131 register int regno
, last_regno
;
1134 /* Can't use cc0_rtx below since this file is used by genattrtab.c. */
1135 if (GET_CODE (x
) == CC0
)
1138 if (GET_CODE (x
) != REG
)
1142 last_regno
= (regno
>= FIRST_PSEUDO_REGISTER
? regno
1143 : regno
+ HARD_REGNO_NREGS (regno
, GET_MODE (x
)) - 1);
1145 for (i
= regno
; i
<= last_regno
; i
++)
1146 if (! dead_or_set_regno_p (insn
, i
))
1152 /* Utility function for dead_or_set_p to check an individual register. Also
1153 called from flow.c. */
1156 dead_or_set_regno_p (insn
, test_regno
)
1160 int regno
, endregno
;
1163 /* REG_READ notes are not normally maintained after reload, so we
1164 ignore them if the are invalid. */
1165 if (! reload_completed
1166 #ifdef PRESERVE_DEATH_INFO_REGNO_P
1167 || PRESERVE_DEATH_INFO_REGNO_P (test_regno
)
1171 /* See if there is a death note for something that includes
1173 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
1175 if (REG_NOTE_KIND (link
) != REG_DEAD
1176 || GET_CODE (XEXP (link
, 0)) != REG
)
1179 regno
= REGNO (XEXP (link
, 0));
1180 endregno
= (regno
>= FIRST_PSEUDO_REGISTER
? regno
+ 1
1181 : regno
+ HARD_REGNO_NREGS (regno
,
1182 GET_MODE (XEXP (link
, 0))));
1184 if (test_regno
>= regno
&& test_regno
< endregno
)
1189 if (GET_CODE (insn
) == CALL_INSN
1190 && find_regno_fusage (insn
, CLOBBER
, test_regno
))
1193 if (GET_CODE (PATTERN (insn
)) == SET
)
1195 rtx dest
= SET_DEST (PATTERN (insn
));
1197 /* A value is totally replaced if it is the destination or the
1198 destination is a SUBREG of REGNO that does not change the number of
1200 if (GET_CODE (dest
) == SUBREG
1201 && (((GET_MODE_SIZE (GET_MODE (dest
))
1202 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
1203 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest
)))
1204 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)))
1205 dest
= SUBREG_REG (dest
);
1207 if (GET_CODE (dest
) != REG
)
1210 regno
= REGNO (dest
);
1211 endregno
= (regno
>= FIRST_PSEUDO_REGISTER
? regno
+ 1
1212 : regno
+ HARD_REGNO_NREGS (regno
, GET_MODE (dest
)));
1214 return (test_regno
>= regno
&& test_regno
< endregno
);
1216 else if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
1220 for (i
= XVECLEN (PATTERN (insn
), 0) - 1; i
>= 0; i
--)
1222 rtx body
= XVECEXP (PATTERN (insn
), 0, i
);
1224 if (GET_CODE (body
) == SET
|| GET_CODE (body
) == CLOBBER
)
1226 rtx dest
= SET_DEST (body
);
1228 if (GET_CODE (dest
) == SUBREG
1229 && (((GET_MODE_SIZE (GET_MODE (dest
))
1230 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
1231 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest
)))
1232 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)))
1233 dest
= SUBREG_REG (dest
);
1235 if (GET_CODE (dest
) != REG
)
1238 regno
= REGNO (dest
);
1239 endregno
= (regno
>= FIRST_PSEUDO_REGISTER
? regno
+ 1
1240 : regno
+ HARD_REGNO_NREGS (regno
, GET_MODE (dest
)));
1242 if (test_regno
>= regno
&& test_regno
< endregno
)
1251 /* Return the reg-note of kind KIND in insn INSN, if there is one.
1252 If DATUM is nonzero, look for one whose datum is DATUM. */
1255 find_reg_note (insn
, kind
, datum
)
1262 /* Ignore anything that is not an INSN, JUMP_INSN or CALL_INSN. */
1263 if (GET_RTX_CLASS (GET_CODE (insn
)) != 'i')
1266 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
1267 if (REG_NOTE_KIND (link
) == kind
1268 && (datum
== 0 || datum
== XEXP (link
, 0)))
1273 /* Return the reg-note of kind KIND in insn INSN which applies to register
1274 number REGNO, if any. Return 0 if there is no such reg-note. Note that
1275 the REGNO of this NOTE need not be REGNO if REGNO is a hard register;
1276 it might be the case that the note overlaps REGNO. */
1279 find_regno_note (insn
, kind
, regno
)
1286 /* Ignore anything that is not an INSN, JUMP_INSN or CALL_INSN. */
1287 if (GET_RTX_CLASS (GET_CODE (insn
)) != 'i')
1290 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
1291 if (REG_NOTE_KIND (link
) == kind
1292 /* Verify that it is a register, so that scratch and MEM won't cause a
1294 && GET_CODE (XEXP (link
, 0)) == REG
1295 && REGNO (XEXP (link
, 0)) <= regno
1296 && ((REGNO (XEXP (link
, 0))
1297 + (REGNO (XEXP (link
, 0)) >= FIRST_PSEUDO_REGISTER
? 1
1298 : HARD_REGNO_NREGS (REGNO (XEXP (link
, 0)),
1299 GET_MODE (XEXP (link
, 0)))))
1305 /* Return true if DATUM, or any overlap of DATUM, of kind CODE is found
1306 in the CALL_INSN_FUNCTION_USAGE information of INSN. */
1309 find_reg_fusage (insn
, code
, datum
)
1314 /* If it's not a CALL_INSN, it can't possibly have a
1315 CALL_INSN_FUNCTION_USAGE field, so don't bother checking. */
1316 if (GET_CODE (insn
) != CALL_INSN
)
1322 if (GET_CODE (datum
) != REG
)
1326 for (link
= CALL_INSN_FUNCTION_USAGE (insn
);
1328 link
= XEXP (link
, 1))
1329 if (GET_CODE (XEXP (link
, 0)) == code
1330 && rtx_equal_p (datum
, SET_DEST (XEXP (link
, 0))))
1335 register int regno
= REGNO (datum
);
1337 /* CALL_INSN_FUNCTION_USAGE information cannot contain references
1338 to pseudo registers, so don't bother checking. */
1340 if (regno
< FIRST_PSEUDO_REGISTER
)
1342 int end_regno
= regno
+ HARD_REGNO_NREGS (regno
, GET_MODE (datum
));
1345 for (i
= regno
; i
< end_regno
; i
++)
1346 if (find_regno_fusage (insn
, code
, i
))
1354 /* Return true if REGNO, or any overlap of REGNO, of kind CODE is found
1355 in the CALL_INSN_FUNCTION_USAGE information of INSN. */
1358 find_regno_fusage (insn
, code
, regno
)
1365 /* CALL_INSN_FUNCTION_USAGE information cannot contain references
1366 to pseudo registers, so don't bother checking. */
1368 if (regno
>= FIRST_PSEUDO_REGISTER
1369 || GET_CODE (insn
) != CALL_INSN
)
1372 for (link
= CALL_INSN_FUNCTION_USAGE (insn
); link
; link
= XEXP (link
, 1))
1374 register int regnote
;
1377 if (GET_CODE (op
= XEXP (link
, 0)) == code
1378 && GET_CODE (SET_DEST (op
)) == REG
1379 && (regnote
= REGNO (SET_DEST (op
))) <= regno
1381 + HARD_REGNO_NREGS (regnote
, GET_MODE (SET_DEST (op
)))
1389 /* Remove register note NOTE from the REG_NOTES of INSN. */
1392 remove_note (insn
, note
)
1398 if (REG_NOTES (insn
) == note
)
1400 REG_NOTES (insn
) = XEXP (note
, 1);
1404 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
1405 if (XEXP (link
, 1) == note
)
1407 XEXP (link
, 1) = XEXP (note
, 1);
1414 /* Nonzero if X contains any volatile instructions. These are instructions
1415 which may cause unpredictable machine state instructions, and thus no
1416 instructions should be moved or combined across them. This includes
1417 only volatile asms and UNSPEC_VOLATILE instructions. */
1423 register RTX_CODE code
;
1425 code
= GET_CODE (x
);
1445 case UNSPEC_VOLATILE
:
1446 /* case TRAP_IF: This isn't clear yet. */
1450 if (MEM_VOLATILE_P (x
))
1457 /* Recursively scan the operands of this expression. */
1460 register char *fmt
= GET_RTX_FORMAT (code
);
1463 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1467 if (volatile_insn_p (XEXP (x
, i
)))
1473 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1474 if (volatile_insn_p (XVECEXP (x
, i
, j
)))
1482 /* Nonzero if X contains any volatile memory references
1483 UNSPEC_VOLATILE operations or volatile ASM_OPERANDS expressions. */
1489 register RTX_CODE code
;
1491 code
= GET_CODE (x
);
1510 case UNSPEC_VOLATILE
:
1511 /* case TRAP_IF: This isn't clear yet. */
1516 if (MEM_VOLATILE_P (x
))
1523 /* Recursively scan the operands of this expression. */
1526 register char *fmt
= GET_RTX_FORMAT (code
);
1529 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1533 if (volatile_refs_p (XEXP (x
, i
)))
1539 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1540 if (volatile_refs_p (XVECEXP (x
, i
, j
)))
1548 /* Similar to above, except that it also rejects register pre- and post-
1555 register RTX_CODE code
;
1557 code
= GET_CODE (x
);
1575 /* Reject CLOBBER with a non-VOID mode. These are made by combine.c
1576 when some combination can't be done. If we see one, don't think
1577 that we can simplify the expression. */
1578 return (GET_MODE (x
) != VOIDmode
);
1585 case UNSPEC_VOLATILE
:
1586 /* case TRAP_IF: This isn't clear yet. */
1591 if (MEM_VOLATILE_P (x
))
1598 /* Recursively scan the operands of this expression. */
1601 register char *fmt
= GET_RTX_FORMAT (code
);
1604 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1608 if (side_effects_p (XEXP (x
, i
)))
1614 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1615 if (side_effects_p (XVECEXP (x
, i
, j
)))
1623 /* Return nonzero if evaluating rtx X might cause a trap. */
1635 code
= GET_CODE (x
);
1638 /* Handle these cases quickly. */
1650 /* Conditional trap can trap! */
1651 case UNSPEC_VOLATILE
:
1655 /* Memory ref can trap unless it's a static var or a stack slot. */
1657 return rtx_addr_can_trap_p (XEXP (x
, 0));
1659 /* Division by a non-constant might trap. */
1664 if (! CONSTANT_P (XEXP (x
, 1))
1665 || GET_MODE_CLASS (GET_MODE (x
)) == MODE_FLOAT
)
1667 /* This was const0_rtx, but by not using that,
1668 we can link this file into other programs. */
1669 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
&& INTVAL (XEXP (x
, 1)) == 0)
1674 /* An EXPR_LIST is used to represent a function call. This
1675 certainly may trap. */
1679 /* Any floating arithmetic may trap. */
1680 if (GET_MODE_CLASS (GET_MODE (x
)) == MODE_FLOAT
)
1684 fmt
= GET_RTX_FORMAT (code
);
1685 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1689 if (may_trap_p (XEXP (x
, i
)))
1692 else if (fmt
[i
] == 'E')
1695 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1696 if (may_trap_p (XVECEXP (x
, i
, j
)))
1703 /* Return nonzero if X contains a comparison that is not either EQ or NE,
1704 i.e., an inequality. */
1707 inequality_comparisons_p (x
)
1711 register int len
, i
;
1712 register enum rtx_code code
= GET_CODE (x
);
1741 len
= GET_RTX_LENGTH (code
);
1742 fmt
= GET_RTX_FORMAT (code
);
1744 for (i
= 0; i
< len
; i
++)
1748 if (inequality_comparisons_p (XEXP (x
, i
)))
1751 else if (fmt
[i
] == 'E')
1754 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
1755 if (inequality_comparisons_p (XVECEXP (x
, i
, j
)))
1763 /* Replace any occurrence of FROM in X with TO.
1765 Note that copying is not done so X must not be shared unless all copies
1766 are to be modified. */
1769 replace_rtx (x
, from
, to
)
1778 /* Allow this function to make replacements in EXPR_LISTs. */
1782 fmt
= GET_RTX_FORMAT (GET_CODE (x
));
1783 for (i
= GET_RTX_LENGTH (GET_CODE (x
)) - 1; i
>= 0; i
--)
1786 XEXP (x
, i
) = replace_rtx (XEXP (x
, i
), from
, to
);
1787 else if (fmt
[i
] == 'E')
1788 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
1789 XVECEXP (x
, i
, j
) = replace_rtx (XVECEXP (x
, i
, j
), from
, to
);
1795 /* Throughout the rtx X, replace many registers according to REG_MAP.
1796 Return the replacement for X (which may be X with altered contents).
1797 REG_MAP[R] is the replacement for register R, or 0 for don't replace.
1798 NREGS is the length of REG_MAP; regs >= NREGS are not mapped.
1800 We only support REG_MAP entries of REG or SUBREG. Also, hard registers
1801 should not be mapped to pseudos or vice versa since validate_change
1804 If REPLACE_DEST is 1, replacements are also done in destinations;
1805 otherwise, only sources are replaced. */
1808 replace_regs (x
, reg_map
, nregs
, replace_dest
)
1814 register enum rtx_code code
;
1821 code
= GET_CODE (x
);
1835 /* Verify that the register has an entry before trying to access it. */
1836 if (REGNO (x
) < nregs
&& reg_map
[REGNO (x
)] != 0)
1838 /* SUBREGs can't be shared. Always return a copy to ensure that if
1839 this replacement occurs more than once then each instance will
1840 get distinct rtx. */
1841 if (GET_CODE (reg_map
[REGNO (x
)]) == SUBREG
)
1842 return copy_rtx (reg_map
[REGNO (x
)]);
1843 return reg_map
[REGNO (x
)];
1848 /* Prevent making nested SUBREGs. */
1849 if (GET_CODE (SUBREG_REG (x
)) == REG
&& REGNO (SUBREG_REG (x
)) < nregs
1850 && reg_map
[REGNO (SUBREG_REG (x
))] != 0
1851 && GET_CODE (reg_map
[REGNO (SUBREG_REG (x
))]) == SUBREG
)
1853 rtx map_val
= reg_map
[REGNO (SUBREG_REG (x
))];
1854 rtx map_inner
= SUBREG_REG (map_val
);
1856 if (GET_MODE (x
) == GET_MODE (map_inner
))
1860 /* We cannot call gen_rtx here since we may be linked with
1862 /* Let's try clobbering the incoming SUBREG and see
1863 if this is really safe. */
1864 SUBREG_REG (x
) = map_inner
;
1865 SUBREG_WORD (x
) += SUBREG_WORD (map_val
);
1868 rtx
new = rtx_alloc (SUBREG
);
1869 PUT_MODE (new, GET_MODE (x
));
1870 SUBREG_REG (new) = map_inner
;
1871 SUBREG_WORD (new) = SUBREG_WORD (x
) + SUBREG_WORD (map_val
);
1879 SET_DEST (x
) = replace_regs (SET_DEST (x
), reg_map
, nregs
, 0);
1881 else if (GET_CODE (SET_DEST (x
)) == MEM
1882 || GET_CODE (SET_DEST (x
)) == STRICT_LOW_PART
)
1883 /* Even if we are not to replace destinations, replace register if it
1884 is CONTAINED in destination (destination is memory or
1885 STRICT_LOW_PART). */
1886 XEXP (SET_DEST (x
), 0) = replace_regs (XEXP (SET_DEST (x
), 0),
1888 else if (GET_CODE (SET_DEST (x
)) == ZERO_EXTRACT
)
1889 /* Similarly, for ZERO_EXTRACT we replace all operands. */
1892 SET_SRC (x
) = replace_regs (SET_SRC (x
), reg_map
, nregs
, 0);
1899 fmt
= GET_RTX_FORMAT (code
);
1900 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1903 XEXP (x
, i
) = replace_regs (XEXP (x
, i
), reg_map
, nregs
, replace_dest
);
1907 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1908 XVECEXP (x
, i
, j
) = replace_regs (XVECEXP (x
, i
, j
), reg_map
,
1909 nregs
, replace_dest
);
1915 /* Return 1 if X, the SRC_SRC of SET of (pc) contain a REG or MEM that is
1916 not in the constant pool and not in the condition of an IF_THEN_ELSE. */
1919 jmp_uses_reg_or_mem (x
)
1922 enum rtx_code code
= GET_CODE (x
);
1937 return ! (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
1938 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)));
1941 return (jmp_uses_reg_or_mem (XEXP (x
, 1))
1942 || jmp_uses_reg_or_mem (XEXP (x
, 2)));
1944 case PLUS
: case MINUS
: case MULT
:
1945 return (jmp_uses_reg_or_mem (XEXP (x
, 0))
1946 || jmp_uses_reg_or_mem (XEXP (x
, 1)));
1952 fmt
= GET_RTX_FORMAT (code
);
1953 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1956 && jmp_uses_reg_or_mem (XEXP (x
, i
)))
1960 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1961 if (jmp_uses_reg_or_mem (XVECEXP (x
, i
, j
)))
1968 /* Return nonzero if INSN is an indirect jump (aka computed jump).
1970 Tablejumps and casesi insns are not considered indirect jumps;
1971 we can recognize them by a (use (lael_ref)). */
1974 computed_jump_p (insn
)
1978 if (GET_CODE (insn
) == JUMP_INSN
)
1980 rtx pat
= PATTERN (insn
);
1982 if (GET_CODE (pat
) == PARALLEL
)
1984 int len
= XVECLEN (pat
, 0);
1985 int has_use_labelref
= 0;
1987 for (i
= len
- 1; i
>= 0; i
--)
1988 if (GET_CODE (XVECEXP (pat
, 0, i
)) == USE
1989 && (GET_CODE (XEXP (XVECEXP (pat
, 0, i
), 0))
1991 has_use_labelref
= 1;
1993 if (! has_use_labelref
)
1994 for (i
= len
- 1; i
>= 0; i
--)
1995 if (GET_CODE (XVECEXP (pat
, 0, i
)) == SET
1996 && SET_DEST (XVECEXP (pat
, 0, i
)) == pc_rtx
1997 && jmp_uses_reg_or_mem (SET_SRC (XVECEXP (pat
, 0, i
))))
2000 else if (GET_CODE (pat
) == SET
2001 && SET_DEST (pat
) == pc_rtx
2002 && jmp_uses_reg_or_mem (SET_SRC (pat
)))