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basic instcombine support for CDS.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148806 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2012-01-24 14:31:22 +00:00
parent 29cc6cb4d1
commit bec2d03c4d
2 changed files with 32 additions and 14 deletions
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lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+24 -11
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@@ -855,23 +855,36 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
return NewCP != CV ? NewCP : 0;
}
if (isa<ConstantAggregateZero>(V)) {
// Simplify the CAZ to a ConstantVector where the non-demanded elements are
// set to undef.
if (ConstantDataVector *CDV = dyn_cast<ConstantDataVector>(V)) {
// Check if this is identity. If so, return 0 since we are not simplifying
// anything.
if (DemandedElts.isAllOnesValue())
return 0;
// Simplify to a ConstantVector where the non-demanded elements are undef.
Constant *Undef = UndefValue::get(CDV->getElementType());
SmallVector<Constant*, 16> Elts;
for (unsigned i = 0; i != VWidth; ++i)
Elts.push_back(DemandedElts[i] ? CDV->getElementAsConstant(i) : Undef);
UndefElts = DemandedElts ^ EltMask;
return ConstantVector::get(Elts);
}
if (ConstantAggregateZero *CAZ = dyn_cast<ConstantAggregateZero>(V)) {
// Check if this is identity. If so, return 0 since we are not simplifying
// anything.
if (DemandedElts.isAllOnesValue())
return 0;
Type *EltTy = cast<VectorType>(V->getType())->getElementType();
Constant *Zero = Constant::getNullValue(EltTy);
Constant *Undef = UndefValue::get(EltTy);
std::vector<Constant*> Elts;
for (unsigned i = 0; i != VWidth; ++i) {
Constant *Elt = DemandedElts[i] ? Zero : Undef;
Elts.push_back(Elt);
}
// Simplify the CAZ to a ConstantVector where the non-demanded elements are
// set to undef.
Constant *Zero = CAZ->getSequentialElement();
Constant *Undef = UndefValue::get(Zero->getType());
SmallVector<Constant*, 16> Elts;
for (unsigned i = 0; i != VWidth; ++i)
Elts.push_back(DemandedElts[i] ? Zero : Undef);
UndefElts = DemandedElts ^ EltMask;
return ConstantVector::get(Elts);
}