Remove <def,read-undef> flags from partial redefinitions.

The new coalescer can turn a full virtual register definition into a
partial redef by merging another value into an unused vector lane.

Make sure to clear the <read-undef> flag on such defs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164807 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2012-09-27 23:31:32 +00:00
parent 6f6ea93c92
commit 83ef63efce

View File

@ -1732,6 +1732,12 @@ void JoinVals::pruneValues(JoinVals &Other,
case CR_Replace:
// This value takes precedence over the value in Other.LI.
LIS->pruneValue(&Other.LI, Def, &EndPoints);
// Remove <def,read-undef> flags. This def is now a partial redef.
if (!Def.isBlock())
for (MIOperands MO(Indexes->getInstructionFromIndex(Def));
MO.isValid(); ++MO)
if (MO->isReg() && MO->isDef() && MO->getReg() == LI.reg)
MO->setIsUndef(false);
DEBUG(dbgs() << "\t\tpruned " << PrintReg(Other.LI.reg) << " at " << Def
<< ": " << Other.LI << '\n');
break;