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DAG: Use poison for some vector result widening #168290

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DAG: Use poison for some vector result widening #168290

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24 changes: 12 additions & 12 deletions llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5654,7 +5654,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_Convert(SDNode *N) {
// Widen the input and call convert on the widened input vector.
unsigned NumConcat =
WidenEC.getKnownMinValue() / InVTEC.getKnownMinValue();
SmallVector<SDValue, 16> Ops(NumConcat, DAG.getUNDEF(InVT));
SmallVector<SDValue, 16> Ops(NumConcat, DAG.getPOISON(InVT));
Ops[0] = InOp;
SDValue InVec = DAG.getNode(ISD::CONCAT_VECTORS, DL, InWidenVT, Ops);
if (N->getNumOperands() == 1)
Expand All @@ -5673,7 +5673,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_Convert(SDNode *N) {

// Otherwise unroll into some nasty scalar code and rebuild the vector.
EVT EltVT = WidenVT.getVectorElementType();
SmallVector<SDValue, 16> Ops(WidenEC.getFixedValue(), DAG.getUNDEF(EltVT));
SmallVector<SDValue, 16> Ops(WidenEC.getFixedValue(), DAG.getPOISON(EltVT));
// Use the original element count so we don't do more scalar opts than
// necessary.
unsigned MinElts = N->getValueType(0).getVectorNumElements();
Expand Down Expand Up @@ -5756,7 +5756,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_Convert_StrictFP(SDNode *N) {
// Otherwise unroll into some nasty scalar code and rebuild the vector.
EVT EltVT = WidenVT.getVectorElementType();
std::array<EVT, 2> EltVTs = {{EltVT, MVT::Other}};
SmallVector<SDValue, 16> Ops(WidenNumElts, DAG.getUNDEF(EltVT));
SmallVector<SDValue, 16> Ops(WidenNumElts, DAG.getPOISON(EltVT));
SmallVector<SDValue, 32> OpChains;
// Use the original element count so we don't do more scalar opts than
// necessary.
Expand Down Expand Up @@ -5819,7 +5819,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_EXTEND_VECTOR_INREG(SDNode *N) {
}

while (Ops.size() != WidenNumElts)
Ops.push_back(DAG.getUNDEF(WidenSVT));
Ops.push_back(DAG.getPOISON(WidenSVT));

return DAG.getBuildVector(WidenVT, DL, Ops);
}
Expand Down Expand Up @@ -6026,15 +6026,15 @@ SDValue DAGTypeLegalizer::WidenVecRes_BITCAST(SDNode *N) {
// input and then widening it. To avoid this, we widen the input only if
// it results in a legal type.
if (WidenSize % InSize == 0) {
SmallVector<SDValue, 16> Ops(NewNumParts, DAG.getUNDEF(InVT));
SmallVector<SDValue, 16> Ops(NewNumParts, DAG.getPOISON(InVT));
Ops[0] = InOp;

NewVec = DAG.getNode(ISD::CONCAT_VECTORS, dl, NewInVT, Ops);
} else {
SmallVector<SDValue, 16> Ops;
DAG.ExtractVectorElements(InOp, Ops);
Ops.append(WidenSize / InScalarSize - Ops.size(),
DAG.getUNDEF(InVT.getVectorElementType()));
DAG.getPOISON(InVT.getVectorElementType()));

NewVec = DAG.getNode(ISD::BUILD_VECTOR, dl, NewInVT, Ops);
}
Expand Down Expand Up @@ -6088,7 +6088,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_CONCAT_VECTORS(SDNode *N) {
if (WidenNumElts % NumInElts == 0) {
// Add undef vectors to widen to correct length.
unsigned NumConcat = WidenNumElts / NumInElts;
SDValue UndefVal = DAG.getUNDEF(InVT);
SDValue UndefVal = DAG.getPOISON(InVT);
SmallVector<SDValue, 16> Ops(NumConcat);
for (unsigned i=0; i < NumOperands; ++i)
Ops[i] = N->getOperand(i);
Expand Down Expand Up @@ -6146,7 +6146,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_CONCAT_VECTORS(SDNode *N) {
for (unsigned j = 0; j < NumInElts; ++j)
Ops[Idx++] = DAG.getExtractVectorElt(dl, EltVT, InOp, j);
}
SDValue UndefVal = DAG.getUNDEF(EltVT);
SDValue UndefVal = DAG.getPOISON(EltVT);
for (; Idx < WidenNumElts; ++Idx)
Ops[Idx] = UndefVal;
return DAG.getBuildVector(WidenVT, dl, Ops);
Expand Down Expand Up @@ -6213,7 +6213,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_EXTRACT_SUBVECTOR(SDNode *N) {
Parts.push_back(
DAG.getExtractSubvector(dl, PartVT, InOp, IdxVal + I * GCD));
for (; I < WidenNumElts / GCD; ++I)
Parts.push_back(DAG.getUNDEF(PartVT));
Parts.push_back(DAG.getPOISON(PartVT));

return DAG.getNode(ISD::CONCAT_VECTORS, dl, WidenVT, Parts);
}
Expand All @@ -6229,7 +6229,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_EXTRACT_SUBVECTOR(SDNode *N) {
for (i = 0; i < VTNumElts; ++i)
Ops[i] = DAG.getExtractVectorElt(dl, EltVT, InOp, IdxVal + i);

SDValue UndefVal = DAG.getUNDEF(EltVT);
SDValue UndefVal = DAG.getPOISON(EltVT);
for (; i < WidenNumElts; ++i)
Ops[i] = UndefVal;
return DAG.getBuildVector(WidenVT, dl, Ops);
Expand Down Expand Up @@ -6903,7 +6903,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_VECTOR_REVERSE(SDNode *N) {
Parts.push_back(
DAG.getExtractSubvector(dl, PartVT, ReverseVal, IdxVal + i * GCD));
for (; i < WidenNumElts / GCD; ++i)
Parts.push_back(DAG.getUNDEF(PartVT));
Parts.push_back(DAG.getPOISON(PartVT));

return DAG.getNode(ISD::CONCAT_VECTORS, dl, WidenVT, Parts);
}
Expand Down Expand Up @@ -6992,7 +6992,7 @@ SDValue DAGTypeLegalizer::WidenVecRes_STRICT_FSETCC(SDNode *N) {
EVT TmpEltVT = LHS.getValueType().getVectorElementType();

// Fully unroll and reassemble.
SmallVector<SDValue, 8> Scalars(WidenNumElts, DAG.getUNDEF(EltVT));
SmallVector<SDValue, 8> Scalars(WidenNumElts, DAG.getPOISON(EltVT));
SmallVector<SDValue, 8> Chains(NumElts);
for (unsigned i = 0; i != NumElts; ++i) {
SDValue LHSElem = DAG.getExtractVectorElt(dl, TmpEltVT, LHS, i);
Expand Down
7 changes: 0 additions & 7 deletions llvm/test/CodeGen/AArch64/sve-extract-scalable-vector.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -612,13 +612,6 @@ define <vscale x 14 x i8> @extract_nxv14i8_nxv28i8_14(<vscale x 28 x i8> %in) {
; CHECK-NEXT: uunpkhi z3.d, z3.s
; CHECK-NEXT: uzp1 z1.s, z1.s, z3.s
; CHECK-NEXT: uzp1 z1.h, z2.h, z1.h
; CHECK-NEXT: uzp1 z1.b, z0.b, z1.b
; CHECK-NEXT: uunpkhi z1.h, z1.b
; CHECK-NEXT: uunpkhi z2.s, z1.h
; CHECK-NEXT: uunpklo z1.s, z1.h
; CHECK-NEXT: uunpklo z2.d, z2.s
; CHECK-NEXT: uzp1 z2.s, z2.s, z0.s
; CHECK-NEXT: uzp1 z1.h, z1.h, z2.h
; CHECK-NEXT: uzp1 z0.b, z0.b, z1.b
; CHECK-NEXT: ret
%res = call <vscale x 14 x i8> @llvm.vector.extract.nxv14i8.nxv28i8(<vscale x 28 x i8> %in, i64 14)
Expand Down
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