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SROA: Generate selects instead of shuffles when blending values because this is the cannonical form.

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Shuffles are more difficult to lower and we usually don't touch them, while we do optimize selects more often.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180875 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nadav Rotem
2013-05-01 19:53:30 +00:00
parent f0b0755b6e
commit fee6969463
2 changed files with 20 additions and 22 deletions
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14
lib/Transforms/Scalar/SROA.cpp
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@ -2322,17 +2322,15 @@ static Value *insertVector(IRBuilderTy &IRB, Value *Old, Value *V,
V = IRB.CreateShuffleVector(V, UndefValue::get(V->getType()),
ConstantVector::get(Mask),
Name + ".expand");
DEBUG(dbgs() << " shuffle1: " << *V << "\n");
DEBUG(dbgs() << " shuffle: " << *V << "\n");
Mask.clear();
for (unsigned i = 0; i != VecTy->getNumElements(); ++i)
if (i >= BeginIndex && i < EndIndex)
Mask.push_back(IRB.getInt32(i));
else
Mask.push_back(IRB.getInt32(i + VecTy->getNumElements()));
V = IRB.CreateShuffleVector(V, Old, ConstantVector::get(Mask),
Name + "insert");
DEBUG(dbgs() << " shuffle2: " << *V << "\n");
Mask.push_back(IRB.getInt1(i >= BeginIndex && i < EndIndex));
V = IRB.CreateSelect(ConstantVector::get(Mask), V, Old, Name + "blend");
DEBUG(dbgs() << " blend: " << *V << "\n");
return V;
}