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Revert parts of the change for PR25130.

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* cse.c (exp_equiv_p): For MEMs, if for_gcse, only compare
	MEM_ALIAS_SET.

From-SVN: r161534
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Bernd Schmidt 2010-06-29 13:51:37 +00:00 committed by Bernd Schmidt
parent 810c4bf4f0
commit 3df41baf91
2 changed files with 10 additions and 16 deletions
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4
gcc/ChangeLog
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@ -5,6 +5,10 @@
(maddhisi4): Renamed from mulhisi3addsi. Operands renumbered.
(maddhidi4): Likewise.
Revert parts of the change for PR25130.
* cse.c (exp_equiv_p): For MEMs, if for_gcse, only compare
MEM_ALIAS_SET.
2010-06-29 Nathan Froyd <froydnj@codesourcery.com>
* calls.c, dse.c, expr.c, function.c: Call targetm.calls.function_arg,

22
gcc/cse.c
View File

@ -2669,26 +2669,16 @@ exp_equiv_p (const_rtx x, const_rtx y, int validate, bool for_gcse)
case MEM:
if (for_gcse)
{
/* Can't merge two expressions in different alias sets, since we
can decide that the expression is transparent in a block when
it isn't, due to it being set with the different alias set. */
if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y))
return 0;
/* A volatile mem should not be considered equivalent to any
other. */
if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
return 0;
/* Can't merge two expressions in different alias sets, since we
can decide that the expression is transparent in a block when
it isn't, due to it being set with the different alias set.
Also, can't merge two expressions with different MEM_ATTRS.
They could e.g. be two different entities allocated into the
same space on the stack (see e.g. PR25130). In that case, the
MEM addresses can be the same, even though the two MEMs are
absolutely not equivalent.
But because really all MEM attributes should be the same for
equivalent MEMs, we just use the invariant that MEMs that have
the same attributes share the same mem_attrs data structure. */
if (MEM_ATTRS (x) != MEM_ATTRS (y))
return 0;
}
break;