Hi,
Currently reg_set_p doesn't handle sequence rtx, which I've identified
as the root cause of PR 64479. There is another alternative fix for the
PR, but I'd like to get some comments regarding letting reg_set_p also
handle sequence rtx:
Index: gcc/rtlanal.c
===================================================================
--- gcc/rtlanal.c (revision 218544)
+++ gcc/rtlanal.c (working copy)
@@ -875,17 +875,24 @@
{
/* We can be passed an insn or part of one. If we are passed an insn,
check if a side-effect of the insn clobbers REG. */
- if (INSN_P (insn)
- && (FIND_REG_INC_NOTE (insn, reg)
- || (CALL_P (insn)
- && ((REG_P (reg)
- && REGNO (reg) < FIRST_PSEUDO_REGISTER
- && overlaps_hard_reg_set_p (regs_invalidated_by_call,
- GET_MODE (reg), REGNO (reg)))
- || MEM_P (reg)
- || find_reg_fusage (insn, CLOBBER, reg)))))
- return 1;
+ if (INSN_P (insn) && FIND_REG_INC_NOTE (insn, reg))
+ return true;
+ /* After delay slot handling, call and branch insns might be in a
+ sequence. Check all the elements there. */
+ if (INSN_P (insn) && GET_CODE (PATTERN (insn)) == SEQUENCE)
+ for (int i = 0; i < XVECLEN (PATTERN (insn), 0); ++i)
+ if (reg_set_p (reg, XVECEXP (PATTERN (insn), 0, i)))
+ return true;
+
+ if (CALL_P (insn)
+ && ((REG_P (reg) && REGNO (reg) < FIRST_PSEUDO_REGISTER
+ && overlaps_hard_reg_set_p (regs_invalidated_by_call,
+ GET_MODE (reg), REGNO (reg)))
+ || MEM_P (reg)
+ || find_reg_fusage (insn, CLOBBER, reg)))
+ return true;
+
return set_of (reg, insn) != NULL_RTX;
}
Would that be OK to do if it passes testing, or is there something that
could potentially/obviously blow up?
Cheers,
Oleg
