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Fix a performance regression. Use {p}shuf* when there are only two distinct elements in a build_vector. 

llvm-svn: 27945
This commit is contained in:
Evan Cheng 2006-04-22 06:21:46 +00:00
parent 40ff2928ed
commit 16ef94f4e8
1 changed files with 17 additions and 13 deletions
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30
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -3274,22 +3274,26 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
return DAG.getNode(ISD::VECTOR_SHUFFLE, VT, V[0], V[1], ShufMask);
}
// Expand into a number of unpckl*.
// e.g. for v4f32
// Step 1: unpcklps 0, 2 ==> X: <?, ?, 2, 0>
// : unpcklps 1, 3 ==> Y: <?, ?, 3, 1>
// Step 2: unpcklps X, Y ==> <3, 2, 1, 0>
SDOperand UnpckMask = getUnpacklMask(NumElems, DAG);
for (unsigned i = 0; i < NumElems; ++i)
V[i] = DAG.getNode(ISD::SCALAR_TO_VECTOR, VT, Op.getOperand(i));
NumElems >>= 1;
while (NumElems != 0) {
if (Values.size() > 2) {
// Expand into a number of unpckl*.
// e.g. for v4f32
// Step 1: unpcklps 0, 2 ==> X: <?, ?, 2, 0>
// : unpcklps 1, 3 ==> Y: <?, ?, 3, 1>
// Step 2: unpcklps X, Y ==> <3, 2, 1, 0>
SDOperand UnpckMask = getUnpacklMask(NumElems, DAG);
for (unsigned i = 0; i < NumElems; ++i)
V[i] = DAG.getNode(ISD::VECTOR_SHUFFLE, VT, V[i], V[i + NumElems],
UnpckMask);
V[i] = DAG.getNode(ISD::SCALAR_TO_VECTOR, VT, Op.getOperand(i));
NumElems >>= 1;
while (NumElems != 0) {
for (unsigned i = 0; i < NumElems; ++i)
V[i] = DAG.getNode(ISD::VECTOR_SHUFFLE, VT, V[i], V[i + NumElems],
UnpckMask);
NumElems >>= 1;
}
return V[0];
}
return V[0];
return SDOperand();
}
case ISD::EXTRACT_VECTOR_ELT: {
if (!isa<ConstantSDNode>(Op.getOperand(1)))