Hi,
in the testcase we die in post-reload cprop because updating one insn clobber
actually affect other insn clobber. I actually introduced clobber sharing back
in 2005 to save memory for (clobber cc0). This broke with introduction of post-reload
code copying that is now done by shrink wrapping.
Fixed by unsharing those clobbers that originate from pseudos.
Bootstrapped/regtested x86_64-linux, OK?
PR middle-end/56571
* valtrack.c (cleanup_auto_inc_dec): Unshare clobbers originating
from pseudos.
* emit-rtl.c (verify_rtx_sharing): Likewise.
(copy_insn_1): Likewise.
* rtl.c (copy_rtx): Likewise.
* gcc.c-torture/compile/pr56571.c: New testcase.
Index: valtrack.c
===================================================================
*** valtrack.c (revision 196596)
--- valtrack.c (working copy)
*************** cleanup_auto_inc_dec (rtx src, enum mach
*** 71,77 ****
/* SCRATCH must be shared because they represent distinct values. */
return x;
case CLOBBER:
! if (REG_P (XEXP (x, 0)) && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER)
return x;
break;
--- 71,78 ----
/* SCRATCH must be shared because they represent distinct values. */
return x;
case CLOBBER:
! if (REG_P (XEXP (x, 0)) && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER
! && ORIGINAL_REGNO (XEXP (x, 0)) == REGNO (XEXP (x, 0)))
return x;
break;
*************** copy_insn_1 (rtx orig)
*** 5303,5309 ****
case SIMPLE_RETURN:
return orig;
case CLOBBER:
! if (REG_P (XEXP (orig, 0)) && REGNO (XEXP (orig, 0)) < FIRST_PSEUDO_REGISTER)
return orig;
break;
--- 5311,5318 ----
case SIMPLE_RETURN:
return orig;
case CLOBBER:
! if (REG_P (XEXP (orig, 0)) && REGNO (XEXP (orig, 0)) < FIRST_PSEUDO_REGISTER
! && ORIGINAL_REGNO (XEXP (orig, 0)) == REGNO (XEXP (orig, 0)))
return orig;
break;