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Fix an expensive-checks error. 

The Mask and LHSMask may not be of the same size, so don't do the
transformation if they're different.

llvm-svn: 88972
This commit is contained in:
David Greene 2009-11-16 21:52:23 +00:00
parent c2ef215bda
commit a3ce7828b2
1 changed files with 24 additions and 20 deletions
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44
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
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@ -12917,29 +12917,33 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
if (isa<UndefValue>(RHS)) { if (isa<UndefValue>(RHS)) {
std::vector<unsigned> LHSMask = getShuffleMask(LHSSVI); std::vector<unsigned> LHSMask = getShuffleMask(LHSSVI);
std::vector<unsigned> NewMask; if (LHSMask.size() == Mask.size()) {
for (unsigned i = 0, e = Mask.size(); i != e; ++i) std::vector<unsigned> NewMask;
if (Mask[i] >= 2*e) for (unsigned i = 0, e = Mask.size(); i != e; ++i)
NewMask.push_back(2*e); if (Mask[i] >= 2*e)
else NewMask.push_back(2*e);
NewMask.push_back(LHSMask[Mask[i]]); else
NewMask.push_back(LHSMask[Mask[i]]);
// If the result mask is equal to the src shuffle or this shuffle mask, do // If the result mask is equal to the src shuffle or this
// the replacement. // shuffle mask, do the replacement.
if (NewMask == LHSMask || NewMask == Mask) { if (NewMask == LHSMask || NewMask == Mask) {
unsigned LHSInNElts = unsigned LHSInNElts =
cast<VectorType>(LHSSVI->getOperand(0)->getType())->getNumElements(); cast<VectorType>(LHSSVI->getOperand(0)->getType())->
std::vector<Constant*> Elts; getNumElements();
for (unsigned i = 0, e = NewMask.size(); i != e; ++i) { std::vector<Constant*> Elts;
if (NewMask[i] >= LHSInNElts*2) { for (unsigned i = 0, e = NewMask.size(); i != e; ++i) {
Elts.push_back(UndefValue::get(Type::getInt32Ty(*Context))); if (NewMask[i] >= LHSInNElts*2) {
} else { Elts.push_back(UndefValue::get(Type::getInt32Ty(*Context)));
Elts.push_back(ConstantInt::get(Type::getInt32Ty(*Context), NewMask[i])); } else {
Elts.push_back(ConstantInt::get(Type::getInt32Ty(*Context),
NewMask[i]));
}
} }
return new ShuffleVectorInst(LHSSVI->getOperand(0),
LHSSVI->getOperand(1),
ConstantVector::get(Elts));
} }
return new ShuffleVectorInst(LHSSVI->getOperand(0),
LHSSVI->getOperand(1),
ConstantVector::get(Elts));
} }
} }
} }