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re PR rtl-optimization/6086 (Reload misoptimizes DImode PREINC on PPC)

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PR optimization/6086
	* combine.c (combine_simplify_rtx): If simplify_rtx failed because
	of SUBREG of volatile MEM or because the MEM was mode dependent,
	return CLOBBER instead of unmodified SUBREG.

From-SVN: r51606
This commit is contained in:
Jakub Jelinek 2002-03-30 19:50:34 +01:00 • committed by Jakub Jelinek
parent 1540f9ebc4
commit 30984c5791
2 changed files with 14 additions and 0 deletions
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gcc/ChangeLog
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@ -1,3 +1,10 @@
2002-03-30 Jakub Jelinek <jakub@redhat.com>
PR optimization/6086
* combine.c (combine_simplify_rtx): If simplify_rtx failed because
of SUBREG of volatile MEM or because the MEM was mode dependent,
return CLOBBER instead of unmodified SUBREG.
Sat Mar 30 14:08:55 CET 2002 Jan Hubicka <jh@suse.cz>
* local-alloc.c (local_alloc): Avoid call of update_equiv_regs when not optimizing.

7
gcc/combine.c
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@ -3875,6 +3875,13 @@ combine_simplify_rtx (x, op0_mode, last, in_dest)
return temp;
}
/* Don't change the mode of the MEM if that would change the meaning
of the address. */
if (GET_CODE (SUBREG_REG (x)) == MEM
&& (MEM_VOLATILE_P (SUBREG_REG (x))
|| mode_dependent_address_p (XEXP (SUBREG_REG (x), 0))))
return gen_rtx_CLOBBER (mode, const0_rtx);
/* Note that we cannot do any narrowing for non-constants since
we might have been counting on using the fact that some bits were
zero. We now do this in the SET. */