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If a shuffle is unary, i.e. one of the vector argument is not needed, turn the 

operand into a undef and adjust mask accordingly.

llvm-svn: 29232
This commit is contained in:
Evan Cheng 2006-07-20 22:44:41 +00:00
parent db3c520931
commit 8472e0c4af
1 changed files with 56 additions and 10 deletions
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66
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -2597,10 +2597,33 @@ SDOperand DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
}
}
if (isIdentity) return N->getOperand(1);
// If the LHS and the RHS are the same node, turn the RHS into an undef.
if (N->getOperand(0) == N->getOperand(1)) {
if (N->getOperand(0).getOpcode() == ISD::UNDEF)
// Check if the shuffle is a unary shuffle, i.e. one of the vectors is not
// needed at all.
bool isUnary = true;
int VecNum = -1;
for (unsigned i = 0; i != NumElts; ++i)
if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) {
unsigned Idx = cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue();
int V = (Idx < NumElts) ? 0 : 1;
if (VecNum == -1)
VecNum = V;
else if (VecNum != V) {
isUnary = false;
break;
}
}
SDOperand N0 = N->getOperand(0);
SDOperand N1 = N->getOperand(1);
// Normalize unary shuffle so the RHS is undef.
if (isUnary && VecNum == 1)
std::swap(N0, N1);
// If it is a unary or the LHS and the RHS are the same node, turn the RHS
// into an undef.
if (isUnary || N0 == N1) {
if (N0.getOpcode() == ISD::UNDEF)
return DAG.getNode(ISD::UNDEF, N->getValueType(0));
// Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the
// first operand.
@ -2619,7 +2642,7 @@ SDOperand DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
MappedOps);
AddToWorkList(ShufMask.Val);
return DAG.getNode(ISD::VECTOR_SHUFFLE, N->getValueType(0),
N->getOperand(0),
N0,
DAG.getNode(ISD::UNDEF, N->getValueType(0)),
ShufMask);
}
@ -2653,8 +2676,31 @@ SDOperand DAGCombiner::visitVVECTOR_SHUFFLE(SDNode *N) {
}
if (isIdentity) return N->getOperand(1);
// If the LHS and the RHS are the same node, turn the RHS into an undef.
if (N->getOperand(0) == N->getOperand(1)) {
// Check if the shuffle is a unary shuffle, i.e. one of the vectors is not
// needed at all.
bool isUnary = true;
int VecNum = -1;
for (unsigned i = 0; i != NumElts; ++i)
if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) {
unsigned Idx = cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue();
int V = (Idx < NumElts) ? 0 : 1;
if (VecNum == -1)
VecNum = V;
else if (VecNum != V) {
isUnary = false;
break;
}
}
SDOperand N0 = N->getOperand(0);
SDOperand N1 = N->getOperand(1);
// Normalize unary shuffle so the RHS is undef.
if (isUnary && VecNum == 1)
std::swap(N0, N1);
// If it is a unary or the LHS and the RHS are the same node, turn the RHS
// into an undef.
if (isUnary || N0 == N1) {
// Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the
// first operand.
std::vector<SDOperand> MappedOps;
@ -2680,12 +2726,12 @@ SDOperand DAGCombiner::visitVVECTOR_SHUFFLE(SDNode *N) {
SDOperand UDVal = DAG.getNode(ISD::UNDEF, MappedOps[0].getValueType());
for (unsigned i = 0; i != NumElts; ++i)
MappedOps[i] = UDVal;
MappedOps[NumElts ] = *(N->getOperand(0).Val->op_end()-2);
MappedOps[NumElts+1] = *(N->getOperand(0).Val->op_end()-1);
MappedOps[NumElts ] = *(N0.Val->op_end()-2);
MappedOps[NumElts+1] = *(N0.Val->op_end()-1);
UDVal = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, MappedOps);
return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector,
N->getOperand(0), UDVal, ShufMask,
N0, UDVal, ShufMask,
MappedOps[NumElts], MappedOps[NumElts+1]);
}