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Simplify shuffle narrowing code a bit. No functional change intended. 

llvm-svn: 156154
This commit is contained in:
Craig Topper 2012-05-04 04:08:44 +00:00
parent dcb0e394a9
commit 59063c0a3d
1 changed files with 16 additions and 22 deletions
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38
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -5914,41 +5914,35 @@ SDValue LowerVECTOR_SHUFFLEv16i8(ShuffleVectorSDNode *SVOp,
static
SDValue RewriteAsNarrowerShuffle(ShuffleVectorSDNode *SVOp,
SelectionDAG &DAG, DebugLoc dl) {
EVT VT = SVOp->getValueType(0);
SDValue V1 = SVOp->getOperand(0);
SDValue V2 = SVOp->getOperand(1);
MVT VT = SVOp->getValueType(0).getSimpleVT();
unsigned NumElems = VT.getVectorNumElements();
unsigned NewWidth = (NumElems == 4) ? 2 : 4;
EVT NewVT;
switch (VT.getSimpleVT().SimpleTy) {
MVT NewVT;
unsigned Scale;
switch (VT.SimpleTy) {
default: llvm_unreachable("Unexpected!");
case MVT::v4f32: NewVT = MVT::v2f64; break;
case MVT::v4i32: NewVT = MVT::v2i64; break;
case MVT::v8i16: NewVT = MVT::v4i32; break;
case MVT::v16i8: NewVT = MVT::v4i32; break;
case MVT::v4f32: NewVT = MVT::v2f64; Scale = 2; break;
case MVT::v4i32: NewVT = MVT::v2i64; Scale = 2; break;
case MVT::v8i16: NewVT = MVT::v4i32; Scale = 2; break;
case MVT::v16i8: NewVT = MVT::v4i32; Scale = 4; break;
}
int Scale = NumElems / NewWidth;
SmallVector<int, 8> MaskVec;
for (unsigned i = 0; i < NumElems; i += Scale) {
for (unsigned i = 0; i != NumElems; i += Scale) {
int StartIdx = -1;
for (int j = 0; j < Scale; ++j) {
for (unsigned j = 0; j != Scale; ++j) {
int EltIdx = SVOp->getMaskElt(i+j);
if (EltIdx < 0)
continue;
if (StartIdx == -1)
StartIdx = EltIdx - (EltIdx % Scale);
if (EltIdx != StartIdx + j)
if (StartIdx < 0)
StartIdx = (EltIdx / Scale);
if (EltIdx != (int)(StartIdx*Scale + j))
return SDValue();
}
if (StartIdx == -1)
MaskVec.push_back(-1);
else
MaskVec.push_back(StartIdx / Scale);
MaskVec.push_back(StartIdx);
}
V1 = DAG.getNode(ISD::BITCAST, dl, NewVT, V1);
V2 = DAG.getNode(ISD::BITCAST, dl, NewVT, V2);
SDValue V1 = DAG.getNode(ISD::BITCAST, dl, NewVT, SVOp->getOperand(0));
SDValue V2 = DAG.getNode(ISD::BITCAST, dl, NewVT, SVOp->getOperand(1));
return DAG.getVectorShuffle(NewVT, dl, V1, V2, &MaskVec[0]);
}