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XformToShuffleWithZero - Added clearer early outs and general tidy up. NFCI 

llvm-svn: 232557
This commit is contained in:
Simon Pilgrim 2015-03-17 22:19:08 +00:00
parent d0cf6c852a
commit 257849f11a
1 changed files with 38 additions and 31 deletions
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69
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -12236,44 +12236,51 @@ SDValue DAGCombiner::visitINSERT_SUBVECTOR(SDNode *N) {
/// vector_shuffle V, Zero, <0, 4, 2, 4>
SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) {
EVT VT = N->getValueType(0);
SDLoc dl(N);
SDValue LHS = N->getOperand(0);
SDValue RHS = N->getOperand(1);
if (N->getOpcode() == ISD::AND) {
if (RHS.getOpcode() == ISD::BITCAST)
RHS = RHS.getOperand(0);
if (RHS.getOpcode() == ISD::BUILD_VECTOR) {
SmallVector<int, 8> Indices;
unsigned NumElts = RHS.getNumOperands();
for (unsigned i = 0; i != NumElts; ++i) {
SDValue Elt = RHS.getOperand(i);
if (!isa<ConstantSDNode>(Elt))
return SDValue();
SDLoc dl(N);
if (cast<ConstantSDNode>(Elt)->isAllOnesValue())
Indices.push_back(i);
else if (cast<ConstantSDNode>(Elt)->isNullValue())
Indices.push_back(NumElts+i);
else
return SDValue();
}
// Make sure we're not running after operation legalization where it
// may have custom lowered the vector shuffles.
if (LegalOperations)
return SDValue();
// Let's see if the target supports this vector_shuffle and make sure
// we're not running after operation legalization where it may have
// custom lowered the vector shuffles.
EVT RVT = RHS.getValueType();
if (LegalOperations || !TLI.isVectorClearMaskLegal(Indices, RVT))
if (N->getOpcode() != ISD::AND)
return SDValue();
if (RHS.getOpcode() == ISD::BITCAST)
RHS = RHS.getOperand(0);
if (RHS.getOpcode() == ISD::BUILD_VECTOR) {
SmallVector<int, 8> Indices;
unsigned NumElts = RHS.getNumOperands();
for (unsigned i = 0; i != NumElts; ++i) {
SDValue Elt = RHS.getOperand(i);
if (!isa<ConstantSDNode>(Elt))
return SDValue();
// Return the new VECTOR_SHUFFLE node.
EVT EltVT = RVT.getVectorElementType();
SmallVector<SDValue,8> ZeroOps(RVT.getVectorNumElements(),
DAG.getConstant(0, EltVT));
SDValue Zero = DAG.getNode(ISD::BUILD_VECTOR, SDLoc(N), RVT, ZeroOps);
LHS = DAG.getNode(ISD::BITCAST, dl, RVT, LHS);
SDValue Shuf = DAG.getVectorShuffle(RVT, dl, LHS, Zero, &Indices[0]);
return DAG.getNode(ISD::BITCAST, dl, VT, Shuf);
if (cast<ConstantSDNode>(Elt)->isAllOnesValue())
Indices.push_back(i);
else if (cast<ConstantSDNode>(Elt)->isNullValue())
Indices.push_back(NumElts+i);
else
return SDValue();
}
// Let's see if the target supports this vector_shuffle.
EVT RVT = RHS.getValueType();
if (!TLI.isVectorClearMaskLegal(Indices, RVT))
return SDValue();
// Return the new VECTOR_SHUFFLE node.
EVT EltVT = RVT.getVectorElementType();
SmallVector<SDValue,8> ZeroOps(RVT.getVectorNumElements(),
DAG.getConstant(0, EltVT));
SDValue Zero = DAG.getNode(ISD::BUILD_VECTOR, SDLoc(N), RVT, ZeroOps);
LHS = DAG.getNode(ISD::BITCAST, dl, RVT, LHS);
SDValue Shuf = DAG.getVectorShuffle(RVT, dl, LHS, Zero, &Indices[0]);
return DAG.getNode(ISD::BITCAST, dl, VT, Shuf);
}
return SDValue();