1 /* Analyze RTL for C-Compiler
2 Copyright (C) 1987, 1988, 1991 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, 675 Mass Ave, Cambridge, MA 02139, USA. */
27 /* Bit flags that specify the machine subtype we are compiling for.
28 Bits are tested using macros TARGET_... defined in the tm.h file
29 and set by `-m...' switches. Must be defined in rtlanal.c. */
33 /* Return 1 if the value of X is unstable
34 (would be different at a different point in the program).
35 The frame pointer, arg pointer, etc. are considered stable
36 (within one function) and so is anything marked `unchanging'. */
42 register RTX_CODE code = GET_CODE (x);
47 return ! RTX_UNCHANGING_P (x);
52 if (code == CONST || code == CONST_INT)
56 return ! (REGNO (x) == FRAME_POINTER_REGNUM
57 || REGNO (x) == ARG_POINTER_REGNUM
58 || RTX_UNCHANGING_P (x));
60 fmt = GET_RTX_FORMAT (code);
61 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
63 if (rtx_unstable_p (XEXP (x, i)))
68 /* Return 1 if X has a value that can vary even between two
69 executions of the program. 0 means X can be compared reliably
70 against certain constants or near-constants.
71 The frame pointer and the arg pointer are considered constant. */
77 register RTX_CODE code = GET_CODE (x);
95 /* Note that we have to test for the actual rtx used for the frame
96 and arg pointers and not just the register number in case we have
97 eliminated the frame and/or arg pointer and are using it
99 return ! (x == frame_pointer_rtx || x == arg_pointer_rtx);
102 /* The operand 0 of a LO_SUM is considered constant
103 (in fact is it related specifically to operand 1). */
104 return rtx_varies_p (XEXP (x, 1));
107 fmt = GET_RTX_FORMAT (code);
108 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
110 if (rtx_varies_p (XEXP (x, i)))
115 /* Return 0 if the use of X as an address in a MEM can cause a trap. */
118 rtx_addr_can_trap_p (x)
121 register enum rtx_code code = GET_CODE (x);
127 /* SYMBOL_REF is problematic due to the possible presence of
128 a #pragma weak, but to say that loads from symbols can trap is
129 *very* costly. It's not at all clear what's best here. For
130 now, we ignore the impact of #pragma weak. */
134 /* As in rtx_varies_p, we have to use the actual rtx, not reg number. */
135 return ! (x == frame_pointer_rtx || x == stack_pointer_rtx
136 || x == arg_pointer_rtx);
139 return rtx_addr_can_trap_p (XEXP (x, 0));
142 /* An address is assumed not to trap if it is an address that can't
143 trap plus a constant integer. */
144 return (rtx_addr_can_trap_p (XEXP (x, 0))
145 || GET_CODE (XEXP (x, 1)) != CONST_INT);
148 return rtx_addr_can_trap_p (XEXP (x, 1));
151 /* If it isn't one of the case above, it can cause a trap. */
155 /* Return 1 if X refers to a memory location whose address
156 cannot be compared reliably with constant addresses,
157 or if X refers to a BLKmode memory object. */
160 rtx_addr_varies_p (x)
163 register enum rtx_code code;
172 return GET_MODE (x) == BLKmode || rtx_varies_p (XEXP (x, 0));
174 fmt = GET_RTX_FORMAT (code);
175 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
177 if (rtx_addr_varies_p (XEXP (x, i)))
182 /* Return the value of the integer term in X, if one is apparent;
184 Only obvious integer terms are detected.
185 This is used in cse.c with the `related_value' field.*/
191 if (GET_CODE (x) == CONST)
194 if (GET_CODE (x) == MINUS
195 && GET_CODE (XEXP (x, 1)) == CONST_INT)
196 return - INTVAL (XEXP (x, 1));
197 if (GET_CODE (x) == PLUS
198 && GET_CODE (XEXP (x, 1)) == CONST_INT)
199 return INTVAL (XEXP (x, 1));
203 /* If X is a constant, return the value sans apparent integer term;
205 Only obvious integer terms are detected. */
208 get_related_value (x)
211 if (GET_CODE (x) != CONST)
214 if (GET_CODE (x) == PLUS
215 && GET_CODE (XEXP (x, 1)) == CONST_INT)
217 else if (GET_CODE (x) == MINUS
218 && GET_CODE (XEXP (x, 1)) == CONST_INT)
223 /* Nonzero if register REG appears somewhere within IN.
224 Also works if REG is not a register; in this case it checks
225 for a subexpression of IN that is Lisp "equal" to REG. */
228 reg_mentioned_p (reg, in)
229 register rtx reg, in;
233 register enum rtx_code code;
241 if (GET_CODE (in) == LABEL_REF)
242 return reg == XEXP (in, 0);
244 code = GET_CODE (in);
248 /* Compare registers by number. */
250 return GET_CODE (reg) == REG && REGNO (in) == REGNO (reg);
252 /* These codes have no constituent expressions
260 return GET_CODE (reg) == CONST_INT && INTVAL (in) == INTVAL (reg);
263 /* These are kept unique for a given value. */
267 if (GET_CODE (reg) == code && rtx_equal_p (reg, in))
270 fmt = GET_RTX_FORMAT (code);
272 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
277 for (j = XVECLEN (in, i) - 1; j >= 0; j--)
278 if (reg_mentioned_p (reg, XVECEXP (in, i, j)))
281 else if (fmt[i] == 'e'
282 && reg_mentioned_p (reg, XEXP (in, i)))
288 /* Return 1 if in between BEG and END, exclusive of BEG and END, there is
289 no CODE_LABEL insn. */
292 no_labels_between_p (beg, end)
296 for (p = NEXT_INSN (beg); p != end; p = NEXT_INSN (p))
297 if (GET_CODE (p) == CODE_LABEL)
302 /* Nonzero if register REG is used in an insn between
303 FROM_INSN and TO_INSN (exclusive of those two). */
306 reg_used_between_p (reg, from_insn, to_insn)
307 rtx reg, from_insn, to_insn;
311 if (from_insn == to_insn)
314 for (insn = NEXT_INSN (from_insn); insn != to_insn; insn = NEXT_INSN (insn))
315 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
316 && reg_overlap_mentioned_p (reg, PATTERN (insn)))
321 /* Nonzero if the old value of X, a register, is referenced in BODY. If X
322 is entirely replaced by a new value and the only use is as a SET_DEST,
323 we do not consider it a reference. */
326 reg_referenced_p (x, body)
332 switch (GET_CODE (body))
335 if (reg_overlap_mentioned_p (x, SET_SRC (body)))
338 /* If the destination is anything other than CC0, PC, a REG or a SUBREG
339 of a REG that occupies all of the REG, the insn references X if
340 it is mentioned in the destination. */
341 if (GET_CODE (SET_DEST (body)) != CC0
342 && GET_CODE (SET_DEST (body)) != PC
343 && GET_CODE (SET_DEST (body)) != REG
344 && ! (GET_CODE (SET_DEST (body)) == SUBREG
345 && GET_CODE (SUBREG_REG (SET_DEST (body))) == REG
346 && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (body))))
347 + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)
348 == ((GET_MODE_SIZE (GET_MODE (SET_DEST (body)))
349 + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)))
350 && reg_overlap_mentioned_p (x, SET_DEST (body)))
355 for (i = ASM_OPERANDS_INPUT_LENGTH (body) - 1; i >= 0; i--)
356 if (reg_overlap_mentioned_p (x, ASM_OPERANDS_INPUT (body, i)))
362 return reg_overlap_mentioned_p (x, body);
365 return reg_overlap_mentioned_p (x, TRAP_CONDITION (body));
368 case UNSPEC_VOLATILE:
370 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
371 if (reg_referenced_p (x, XVECEXP (body, 0, i)))
379 /* Nonzero if register REG is referenced in an insn between
380 FROM_INSN and TO_INSN (exclusive of those two). Sets of REG do
384 reg_referenced_between_p (reg, from_insn, to_insn)
385 rtx reg, from_insn, to_insn;
389 if (from_insn == to_insn)
392 for (insn = NEXT_INSN (from_insn); insn != to_insn; insn = NEXT_INSN (insn))
393 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
394 && reg_referenced_p (reg, PATTERN (insn)))
399 /* Nonzero if register REG is set or clobbered in an insn between
400 FROM_INSN and TO_INSN (exclusive of those two). */
403 reg_set_between_p (reg, from_insn, to_insn)
404 rtx reg, from_insn, to_insn;
408 if (from_insn == to_insn)
411 for (insn = NEXT_INSN (from_insn); insn != to_insn; insn = NEXT_INSN (insn))
412 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
413 && reg_set_p (reg, insn))
418 /* Internals of reg_set_between_p. */
420 static rtx reg_set_reg;
421 static int reg_set_flag;
427 /* We don't want to return 1 if X is a MEM that contains a register
428 within REG_SET_REG. */
430 if ((GET_CODE (x) != MEM)
431 && reg_overlap_mentioned_p (reg_set_reg, x))
436 reg_set_p (reg, insn)
441 /* We can be passed an insn or part of one. If we are passed an insn,
442 check if a side-effect of the insn clobbers REG. */
443 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
445 if (FIND_REG_INC_NOTE (insn, reg)
446 || (GET_CODE (insn) == CALL_INSN
447 /* We'd like to test call_used_regs here, but rtlanal.c can't
448 reference that variable due to its use in genattrtab. So
449 we'll just be more conservative. */
450 && ((GET_CODE (reg) == REG
451 && REGNO (reg) < FIRST_PSEUDO_REGISTER)
452 || GET_CODE (reg) == MEM)))
455 body = PATTERN (insn);
460 note_stores (body, reg_set_p_1);
464 /* Similar to reg_set_between_p, but check all registers in X. Return 0
465 only if none of them are modified between START and END. Return 1 if
466 X contains a MEM; this routine does not perform any memory aliasing. */
469 modified_between_p (x, start, end)
473 enum rtx_code code = GET_CODE (x);
491 /* If the memory is not constant, assume it is modified. If it is
492 constant, we still have to check the address. */
493 if (! RTX_UNCHANGING_P (x))
498 return reg_set_between_p (x, start, end);
501 fmt = GET_RTX_FORMAT (code);
502 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
504 && modified_between_p (XEXP (x, i), start, end))
510 /* Given an INSN, return a SET expression if this insn has only a single SET.
511 It may also have CLOBBERs, USEs, or SET whose output
512 will not be used, which we ignore. */
521 if (GET_RTX_CLASS (GET_CODE (insn)) != 'i')
524 if (GET_CODE (PATTERN (insn)) == SET)
525 return PATTERN (insn);
527 else if (GET_CODE (PATTERN (insn)) == PARALLEL)
529 for (i = 0, set = 0; i < XVECLEN (PATTERN (insn), 0); i++)
530 if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET
531 && ! (find_reg_note (insn, REG_UNUSED,
532 SET_DEST (XVECEXP (PATTERN (insn), 0, i)))
533 || side_effects_p (XVECEXP (PATTERN (insn), 0, i))))
538 set = XVECEXP (PATTERN (insn), 0, i);
546 /* Return the last thing that X was assigned from before *PINSN. Verify that
547 the object is not modified up to VALID_TO. If it was, if we hit
548 a partial assignment to X, or hit a CODE_LABEL first, return X. If we
549 found an assignment, update *PINSN to point to it. */
552 find_last_value (x, pinsn, valid_to)
559 for (p = PREV_INSN (*pinsn); p && GET_CODE (p) != CODE_LABEL;
561 if (GET_RTX_CLASS (GET_CODE (p)) == 'i')
563 rtx set = single_set (p);
564 rtx note = find_reg_note (p, REG_EQUAL, 0);
566 if (set && rtx_equal_p (x, SET_DEST (set)))
568 rtx src = SET_SRC (set);
570 if (note && GET_CODE (XEXP (note, 0)) != EXPR_LIST)
571 src = XEXP (note, 0);
573 if (! modified_between_p (src, PREV_INSN (p), valid_to)
574 /* Reject hard registers because we don't usually want
575 to use them; we'd rather use a pseudo. */
576 && ! (GET_CODE (src) == REG
577 && REGNO (src) < FIRST_PSEUDO_REGISTER))
584 /* If set in non-simple way, we don't have a value. */
585 if (reg_set_p (x, p))
592 /* Return nonzero if register in range [REGNO, ENDREGNO)
593 appears either explicitly or implicitly in X
594 other than being stored into.
596 References contained within the substructure at LOC do not count.
597 LOC may be zero, meaning don't ignore anything. */
600 refers_to_regno_p (regno, endregno, x, loc)
606 register RTX_CODE code;
610 /* The contents of a REG_NONNEG note is always zero, so we must come here
611 upon repeat in case the last REG_NOTE is a REG_NONNEG note. */
622 && regno < i + (i < FIRST_PSEUDO_REGISTER
623 ? HARD_REGNO_NREGS (i, GET_MODE (x))
627 /* If this is a SUBREG of a hard reg, we can see exactly which
628 registers are being modified. Otherwise, handle normally. */
629 if (GET_CODE (SUBREG_REG (x)) == REG
630 && REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER)
632 int inner_regno = REGNO (SUBREG_REG (x)) + SUBREG_WORD (x);
634 = inner_regno + (inner_regno < FIRST_PSEUDO_REGISTER
635 ? HARD_REGNO_NREGS (regno, GET_MODE (x)) : 1);
637 return endregno > inner_regno && regno < inner_endregno;
643 if (&SET_DEST (x) != loc
644 /* Note setting a SUBREG counts as referring to the REG it is in for
645 a pseudo but not for hard registers since we can
646 treat each word individually. */
647 && ((GET_CODE (SET_DEST (x)) == SUBREG
648 && loc != &SUBREG_REG (SET_DEST (x))
649 && GET_CODE (SUBREG_REG (SET_DEST (x))) == REG
650 && REGNO (SUBREG_REG (SET_DEST (x))) >= FIRST_PSEUDO_REGISTER
651 && refers_to_regno_p (regno, endregno,
652 SUBREG_REG (SET_DEST (x)), loc))
653 || (GET_CODE (SET_DEST (x)) != REG
654 && refers_to_regno_p (regno, endregno, SET_DEST (x), loc))))
657 if (code == CLOBBER || loc == &SET_SRC (x))
663 /* X does not match, so try its subexpressions. */
665 fmt = GET_RTX_FORMAT (code);
666 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
668 if (fmt[i] == 'e' && loc != &XEXP (x, i))
676 if (refers_to_regno_p (regno, endregno, XEXP (x, i), loc))
679 else if (fmt[i] == 'E')
682 for (j = XVECLEN (x, i) - 1; j >=0; j--)
683 if (loc != &XVECEXP (x, i, j)
684 && refers_to_regno_p (regno, endregno, XVECEXP (x, i, j), loc))
691 /* Nonzero if modifying X will affect IN. If X is a register or a SUBREG,
692 we check if any register number in X conflicts with the relevant register
693 numbers. If X is a constant, return 0. If X is a MEM, return 1 iff IN
694 contains a MEM (we don't bother checking for memory addresses that can't
695 conflict because we expect this to be a rare case. */
698 reg_overlap_mentioned_p (x, in)
703 if (GET_CODE (x) == SUBREG)
705 regno = REGNO (SUBREG_REG (x));
706 if (regno < FIRST_PSEUDO_REGISTER)
707 regno += SUBREG_WORD (x);
709 else if (GET_CODE (x) == REG)
711 else if (CONSTANT_P (x))
713 else if (GET_CODE (x) == MEM)
718 if (GET_CODE (in) == MEM)
721 fmt = GET_RTX_FORMAT (GET_CODE (in));
723 for (i = GET_RTX_LENGTH (GET_CODE (in)) - 1; i >= 0; i--)
724 if (fmt[i] == 'e' && reg_overlap_mentioned_p (x, XEXP (in, i)))
729 else if (GET_CODE (x) == SCRATCH || GET_CODE (x) == PC
730 || GET_CODE (x) == CC0)
731 return reg_mentioned_p (x, in);
735 endregno = regno + (regno < FIRST_PSEUDO_REGISTER
736 ? HARD_REGNO_NREGS (regno, GET_MODE (x)) : 1);
738 return refers_to_regno_p (regno, endregno, in, 0);
741 /* Used for communications between the next few functions. */
743 static int reg_set_last_unknown;
744 static rtx reg_set_last_value;
745 static int reg_set_last_first_regno, reg_set_last_last_regno;
747 /* Called via note_stores from reg_set_last. */
750 reg_set_last_1 (x, pat)
756 /* If X is not a register, or is not one in the range we care
758 if (GET_CODE (x) != REG)
762 last = first + (first < FIRST_PSEUDO_REGISTER
763 ? HARD_REGNO_NREGS (first, GET_MODE (x)) : 1);
765 if (first >= reg_set_last_last_regno
766 || last <= reg_set_last_first_regno)
769 /* If this is a CLOBBER or is some complex LHS, or doesn't modify
770 exactly the registers we care about, show we don't know the value. */
771 if (GET_CODE (pat) == CLOBBER || SET_DEST (pat) != x
772 || first != reg_set_last_first_regno
773 || last != reg_set_last_last_regno)
774 reg_set_last_unknown = 1;
776 reg_set_last_value = SET_SRC (pat);
779 /* Return the last value to which REG was set prior to INSN. If we can't
780 find it easily, return 0.
782 We only return a REG or constant because it is too hard to check if a
783 MEM remains unchanged. */
786 reg_set_last (x, insn)
790 rtx orig_insn = insn;
792 reg_set_last_first_regno = REGNO (x);
794 reg_set_last_last_regno
795 = reg_set_last_first_regno
796 + (reg_set_last_first_regno < FIRST_PSEUDO_REGISTER
797 ? HARD_REGNO_NREGS (reg_set_last_first_regno, GET_MODE (x)) : 1);
799 reg_set_last_unknown = 0;
800 reg_set_last_value = 0;
802 /* Scan backwards until reg_set_last_1 changed one of the above flags.
803 Stop when we reach a label or X is a hard reg and we reach a
804 CALL_INSN (if reg_set_last_last_regno is a hard reg).
806 If we find a set of X, ensure that its SET_SRC remains unchanged. */
809 insn && GET_CODE (insn) != CODE_LABEL
810 && ! (GET_CODE (insn) == CALL_INSN
811 && reg_set_last_last_regno <= FIRST_PSEUDO_REGISTER);
812 insn = PREV_INSN (insn))
813 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
815 note_stores (PATTERN (insn), reg_set_last_1);
816 if (reg_set_last_unknown)
818 else if (reg_set_last_value)
820 if (CONSTANT_P (reg_set_last_value)
821 || (GET_CODE (reg_set_last_value) == REG
822 && ! reg_set_between_p (reg_set_last_value,
823 NEXT_INSN (insn), orig_insn)))
824 return reg_set_last_value;
833 /* This is 1 until after reload pass. */
834 int rtx_equal_function_value_matters;
836 /* Return 1 if X and Y are identical-looking rtx's.
837 This is the Lisp function EQUAL for rtx arguments. */
845 register enum rtx_code code;
850 if (x == 0 || y == 0)
854 /* Rtx's of different codes cannot be equal. */
855 if (code != GET_CODE (y))
858 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
859 (REG:SI x) and (REG:HI x) are NOT equivalent. */
861 if (GET_MODE (x) != GET_MODE (y))
864 /* REG, LABEL_REF, and SYMBOL_REF can be compared nonrecursively. */
867 /* Until rtl generation is complete, don't consider a reference to the
868 return register of the current function the same as the return from a
869 called function. This eases the job of function integration. Once the
870 distinction is no longer needed, they can be considered equivalent. */
871 return (REGNO (x) == REGNO (y)
872 && (! rtx_equal_function_value_matters
873 || REG_FUNCTION_VALUE_P (x) == REG_FUNCTION_VALUE_P (y)));
874 else if (code == LABEL_REF)
875 return XEXP (x, 0) == XEXP (y, 0);
876 else if (code == SYMBOL_REF)
877 return XSTR (x, 0) == XSTR (y, 0);
878 else if (code == SCRATCH || code == CONST_DOUBLE)
881 /* Compare the elements. If any pair of corresponding elements
882 fail to match, return 0 for the whole things. */
884 fmt = GET_RTX_FORMAT (code);
885 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
891 if (XINT (x, i) != XINT (y, i))
897 /* Two vectors must have the same length. */
898 if (XVECLEN (x, i) != XVECLEN (y, i))
901 /* And the corresponding elements must match. */
902 for (j = 0; j < XVECLEN (x, i); j++)
903 if (rtx_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)) == 0)
908 if (rtx_equal_p (XEXP (x, i), XEXP (y, i)) == 0)
914 if (strcmp (XSTR (x, i), XSTR (y, i)))
919 /* These are just backpointers, so they don't matter. */
925 /* It is believed that rtx's at this level will never
926 contain anything but integers and other rtx's,
927 except for within LABEL_REFs and SYMBOL_REFs. */
935 /* Call FUN on each register or MEM that is stored into or clobbered by X.
936 (X would be the pattern of an insn).
937 FUN receives two arguments:
938 the REG, MEM, CC0 or PC being stored in or clobbered,
939 the SET or CLOBBER rtx that does the store.
941 If the item being stored in or clobbered is a SUBREG of a hard register,
942 the SUBREG will be passed. */
949 if ((GET_CODE (x) == SET || GET_CODE (x) == CLOBBER))
951 register rtx dest = SET_DEST (x);
952 while ((GET_CODE (dest) == SUBREG
953 && (GET_CODE (SUBREG_REG (dest)) != REG
954 || REGNO (SUBREG_REG (dest)) >= FIRST_PSEUDO_REGISTER))
955 || GET_CODE (dest) == ZERO_EXTRACT
956 || GET_CODE (dest) == SIGN_EXTRACT
957 || GET_CODE (dest) == STRICT_LOW_PART)
958 dest = XEXP (dest, 0);
961 else if (GET_CODE (x) == PARALLEL)
964 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
966 register rtx y = XVECEXP (x, 0, i);
967 if (GET_CODE (y) == SET || GET_CODE (y) == CLOBBER)
969 register rtx dest = SET_DEST (y);
970 while ((GET_CODE (dest) == SUBREG
971 && (GET_CODE (SUBREG_REG (dest)) != REG
972 || (REGNO (SUBREG_REG (dest))
973 >= FIRST_PSEUDO_REGISTER)))
974 || GET_CODE (dest) == ZERO_EXTRACT
975 || GET_CODE (dest) == SIGN_EXTRACT
976 || GET_CODE (dest) == STRICT_LOW_PART)
977 dest = XEXP (dest, 0);
984 /* Return nonzero if X's old contents don't survive after INSN.
985 This will be true if X is (cc0) or if X is a register and
986 X dies in INSN or because INSN entirely sets X.
988 "Entirely set" means set directly and not through a SUBREG,
989 ZERO_EXTRACT or SIGN_EXTRACT, so no trace of the old contents remains.
990 Likewise, REG_INC does not count.
992 REG may be a hard or pseudo reg. Renumbering is not taken into account,
993 but for this use that makes no difference, since regs don't overlap
994 during their lifetimes. Therefore, this function may be used
995 at any time after deaths have been computed (in flow.c).
997 If REG is a hard reg that occupies multiple machine registers, this
998 function will only return 1 if each of those registers will be replaced
1002 dead_or_set_p (insn, x)
1006 register int regno, last_regno;
1009 /* Can't use cc0_rtx below since this file is used by genattrtab.c. */
1010 if (GET_CODE (x) == CC0)
1013 if (GET_CODE (x) != REG)
1017 last_regno = (regno >= FIRST_PSEUDO_REGISTER ? regno
1018 : regno + HARD_REGNO_NREGS (regno, GET_MODE (x)) - 1);
1020 for (i = regno; i <= last_regno; i++)
1021 if (! dead_or_set_regno_p (insn, i))
1027 /* Utility function for dead_or_set_p to check an individual register. Also
1028 called from flow.c. */
1031 dead_or_set_regno_p (insn, test_regno)
1035 int regno, endregno;
1038 /* See if there is a death note for something that includes TEST_REGNO. */
1039 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1041 if (REG_NOTE_KIND (link) != REG_DEAD || GET_CODE (XEXP (link, 0)) != REG)
1044 regno = REGNO (XEXP (link, 0));
1045 endregno = (regno >= FIRST_PSEUDO_REGISTER ? regno + 1
1046 : regno + HARD_REGNO_NREGS (regno,
1047 GET_MODE (XEXP (link, 0))));
1049 if (test_regno >= regno && test_regno < endregno)
1053 if (GET_CODE (PATTERN (insn)) == SET)
1055 rtx dest = SET_DEST (PATTERN (insn));
1057 /* A value is totally replaced if it is the destination or the
1058 destination is a SUBREG of REGNO that does not change the number of
1060 if (GET_CODE (dest) == SUBREG
1061 && (((GET_MODE_SIZE (GET_MODE (dest))
1062 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
1063 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest)))
1064 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))
1065 dest = SUBREG_REG (dest);
1067 if (GET_CODE (dest) != REG)
1070 regno = REGNO (dest);
1071 endregno = (regno >= FIRST_PSEUDO_REGISTER ? regno + 1
1072 : regno + HARD_REGNO_NREGS (regno, GET_MODE (dest)));
1074 return (test_regno >= regno && test_regno < endregno);
1076 else if (GET_CODE (PATTERN (insn)) == PARALLEL)
1080 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
1082 rtx body = XVECEXP (PATTERN (insn), 0, i);
1084 if (GET_CODE (body) == SET || GET_CODE (body) == CLOBBER)
1086 rtx dest = SET_DEST (body);
1088 if (GET_CODE (dest) == SUBREG
1089 && (((GET_MODE_SIZE (GET_MODE (dest))
1090 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
1091 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest)))
1092 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))
1093 dest = SUBREG_REG (dest);
1095 if (GET_CODE (dest) != REG)
1098 regno = REGNO (dest);
1099 endregno = (regno >= FIRST_PSEUDO_REGISTER ? regno + 1
1100 : regno + HARD_REGNO_NREGS (regno, GET_MODE (dest)));
1102 if (test_regno >= regno && test_regno < endregno)
1111 /* Return the reg-note of kind KIND in insn INSN, if there is one.
1112 If DATUM is nonzero, look for one whose datum is DATUM. */
1115 find_reg_note (insn, kind, datum)
1122 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1123 if (REG_NOTE_KIND (link) == kind
1124 && (datum == 0 || datum == XEXP (link, 0)))
1129 /* Return the reg-note of kind KIND in insn INSN which applies to register
1130 number REGNO, if any. Return 0 if there is no such reg-note. */
1133 find_regno_note (insn, kind, regno)
1140 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1141 if (REG_NOTE_KIND (link) == kind
1142 /* Verify that it is a register, so that scratch and MEM won't cause a
1144 && GET_CODE (XEXP (link, 0)) == REG
1145 && REGNO (XEXP (link, 0)) == regno)
1150 /* Remove register note NOTE from the REG_NOTES of INSN. */
1153 remove_note (insn, note)
1159 if (REG_NOTES (insn) == note)
1161 REG_NOTES (insn) = XEXP (note, 1);
1165 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1166 if (XEXP (link, 1) == note)
1168 XEXP (link, 1) = XEXP (note, 1);
1175 /* Nonzero if X contains any volatile memory references
1176 UNSPEC_VOLATILE operations or volatile ASM_OPERANDS expressions. */
1182 register RTX_CODE code;
1184 code = GET_CODE (x);
1203 case UNSPEC_VOLATILE:
1204 /* case TRAP_IF: This isn't clear yet. */
1209 if (MEM_VOLATILE_P (x))
1213 /* Recursively scan the operands of this expression. */
1216 register char *fmt = GET_RTX_FORMAT (code);
1219 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1223 if (volatile_refs_p (XEXP (x, i)))
1229 for (j = 0; j < XVECLEN (x, i); j++)
1230 if (volatile_refs_p (XVECEXP (x, i, j)))
1238 /* Similar to above, except that it also rejects register pre- and post-
1245 register RTX_CODE code;
1247 code = GET_CODE (x);
1265 /* Reject CLOBBER with a non-VOID mode. These are made by combine.c
1266 when some combination can't be done. If we see one, don't think
1267 that we can simplify the expression. */
1268 return (GET_MODE (x) != VOIDmode);
1275 case UNSPEC_VOLATILE:
1276 /* case TRAP_IF: This isn't clear yet. */
1281 if (MEM_VOLATILE_P (x))
1285 /* Recursively scan the operands of this expression. */
1288 register char *fmt = GET_RTX_FORMAT (code);
1291 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1295 if (side_effects_p (XEXP (x, i)))
1301 for (j = 0; j < XVECLEN (x, i); j++)
1302 if (side_effects_p (XVECEXP (x, i, j)))
1310 /* Return nonzero if evaluating rtx X might cause a trap. */
1322 code = GET_CODE (x);
1325 /* Handle these cases quickly. */
1337 /* Conditional trap can trap! */
1338 case UNSPEC_VOLATILE:
1342 /* Memory ref can trap unless it's a static var or a stack slot. */
1344 return rtx_addr_can_trap_p (XEXP (x, 0));
1346 /* Division by a non-constant might trap. */
1351 if (! CONSTANT_P (XEXP (x, 1)))
1353 /* This was const0_rtx, but by not using that,
1354 we can link this file into other programs. */
1355 if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) == 0)
1358 /* Any floating arithmetic may trap. */
1359 if (GET_MODE_CLASS (GET_MODE (x)) == MODE_FLOAT)
1363 fmt = GET_RTX_FORMAT (code);
1364 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1368 if (may_trap_p (XEXP (x, i)))
1371 else if (fmt[i] == 'E')
1374 for (j = 0; j < XVECLEN (x, i); j++)
1375 if (may_trap_p (XVECEXP (x, i, j)))
1382 /* Return nonzero if X contains a comparison that is not either EQ or NE,
1383 i.e., an inequality. */
1386 inequality_comparisons_p (x)
1390 register int len, i;
1391 register enum rtx_code code = GET_CODE (x);
1417 len = GET_RTX_LENGTH (code);
1418 fmt = GET_RTX_FORMAT (code);
1420 for (i = 0; i < len; i++)
1424 if (inequality_comparisons_p (XEXP (x, i)))
1427 else if (fmt[i] == 'E')
1430 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
1431 if (inequality_comparisons_p (XVECEXP (x, i, j)))
1439 /* Replace any occurrence of FROM in X with TO.
1441 Note that copying is not done so X must not be shared unless all copies
1442 are to be modified. */
1445 replace_rtx (x, from, to)
1454 /* Allow this function to make replacements in EXPR_LISTs. */
1458 fmt = GET_RTX_FORMAT (GET_CODE (x));
1459 for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
1462 XEXP (x, i) = replace_rtx (XEXP (x, i), from, to);
1463 else if (fmt[i] == 'E')
1464 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
1465 XVECEXP (x, i, j) = replace_rtx (XVECEXP (x, i, j), from, to);
1471 /* Throughout the rtx X, replace many registers according to REG_MAP.
1472 Return the replacement for X (which may be X with altered contents).
1473 REG_MAP[R] is the replacement for register R, or 0 for don't replace.
1474 NREGS is the length of REG_MAP; regs >= NREGS are not mapped.
1476 We only support REG_MAP entries of REG or SUBREG. Also, hard registers
1477 should not be mapped to pseudos or vice versa since validate_change
1480 If REPLACE_DEST is 1, replacements are also done in destinations;
1481 otherwise, only sources are replaced. */
1484 replace_regs (x, reg_map, nregs, replace_dest)
1490 register enum rtx_code code;
1497 code = GET_CODE (x);
1511 /* Verify that the register has an entry before trying to access it. */
1512 if (REGNO (x) < nregs && reg_map[REGNO (x)] != 0)
1513 return reg_map[REGNO (x)];
1517 /* Prevent making nested SUBREGs. */
1518 if (GET_CODE (SUBREG_REG (x)) == REG && REGNO (SUBREG_REG (x)) < nregs
1519 && reg_map[REGNO (SUBREG_REG (x))] != 0
1520 && GET_CODE (reg_map[REGNO (SUBREG_REG (x))]) == SUBREG)
1522 rtx map_val = reg_map[REGNO (SUBREG_REG (x))];
1523 rtx map_inner = SUBREG_REG (map_val);
1525 if (GET_MODE (x) == GET_MODE (map_inner))
1529 /* We cannot call gen_rtx here since we may be linked with
1531 /* Let's try clobbering the incoming SUBREG and see
1532 if this is really safe. */
1533 SUBREG_REG (x) = map_inner;
1534 SUBREG_WORD (x) += SUBREG_WORD (map_val);
1537 rtx new = rtx_alloc (SUBREG);
1538 PUT_MODE (new, GET_MODE (x));
1539 SUBREG_REG (new) = map_inner;
1540 SUBREG_WORD (new) = SUBREG_WORD (x) + SUBREG_WORD (map_val);
1548 SET_DEST (x) = replace_regs (SET_DEST (x), reg_map, nregs, 0);
1550 else if (GET_CODE (SET_DEST (x)) == MEM
1551 || GET_CODE (SET_DEST (x)) == STRICT_LOW_PART)
1552 /* Even if we are not to replace destinations, replace register if it
1553 is CONTAINED in destination (destination is memory or
1554 STRICT_LOW_PART). */
1555 XEXP (SET_DEST (x), 0) = replace_regs (XEXP (SET_DEST (x), 0),
1557 else if (GET_CODE (SET_DEST (x)) == ZERO_EXTRACT)
1558 /* Similarly, for ZERO_EXTRACT we replace all operands. */
1561 SET_SRC (x) = replace_regs (SET_SRC (x), reg_map, nregs, 0);
1565 fmt = GET_RTX_FORMAT (code);
1566 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1569 XEXP (x, i) = replace_regs (XEXP (x, i), reg_map, nregs, replace_dest);
1573 for (j = 0; j < XVECLEN (x, i); j++)
1574 XVECEXP (x, i, j) = replace_regs (XVECEXP (x, i, j), reg_map,
1575 nregs, replace_dest);