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Add support for inserting undef into a vector. This implements 

Transforms/InstCombine/vec_insert_to_shuffle.ll

llvm-svn: 27997
This commit is contained in:
Chris Lattner 2006-04-27 21:14:21 +00:00
parent 51fecaa8b3
commit b6cb64b7e6
1 changed files with 14 additions and 3 deletions
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17
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
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@ -6959,12 +6959,23 @@ static bool CollectSingleShuffleElements(Value *V, Value *LHS, Value *RHS,
Value *ScalarOp = IEI->getOperand(1);
Value *IdxOp = IEI->getOperand(2);
if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
if (!isa<ConstantInt>(IdxOp))
return false;
unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getRawValue();
if (isa<UndefValue>(ScalarOp)) { // inserting undef into vector.
// Okay, we can handle this if the vector we are insertinting into is
// transitively ok.
if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
// If so, update the mask to reflect the inserted undef.
Mask[InsertedIdx] = UndefValue::get(Type::UIntTy);
return true;
}
} else if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)){
if (isa<ConstantInt>(EI->getOperand(1)) &&
EI->getOperand(0)->getType() == V->getType()) {
unsigned ExtractedIdx =
cast<ConstantInt>(EI->getOperand(1))->getRawValue();
unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getRawValue();
// This must be extracting from either LHS or RHS.
if (EI->getOperand(0) == LHS || EI->getOperand(0) == RHS) {