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basic instcombine support for CDS. 

llvm-svn: 148806
This commit is contained in:
Chris Lattner 2012-01-24 14:31:22 +00:00
parent 139822fc83
commit a0d01ff567
2 changed files with 32 additions and 14 deletions
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35
llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
View File

@ -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);
}

11
llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
View File

@ -16,7 +16,8 @@
using namespace llvm;
/// CheapToScalarize - Return true if the value is cheaper to scalarize than it
/// is to leave as a vector operation.
/// is to leave as a vector operation. isConstant indicates whether we're
/// extracting one known element. If false we're extracting a variable index.
static bool CheapToScalarize(Value *V, bool isConstant) {
if (isa<ConstantAggregateZero>(V))
return true;
@ -335,10 +336,14 @@ static Value *CollectShuffleElements(Value *V, std::vector<Constant*> &Mask,
if (isa<UndefValue>(V)) {
Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext())));
return V;
} else if (isa<ConstantAggregateZero>(V)) {
}
if (isa<ConstantAggregateZero>(V)) {
Mask.assign(NumElts, ConstantInt::get(Type::getInt32Ty(V->getContext()),0));
return V;
} else if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) {
}
if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) {
// If this is an insert of an extract from some other vector, include it.
Value *VecOp = IEI->getOperand(0);
Value *ScalarOp = IEI->getOperand(1);