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[X86] combineINSERT_SUBVECTOR - use concatSubVectors instead of direct fold to X86ISD::SUBV_BROADCAST_LOAD #140919

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Merged
merged 1 commit into from
May 21, 2025
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[X86] combineINSERT_SUBVECTOR - use concatSubVectors instead of direct fold to X86ISD::SUBV_BROADCAST_LOAD #140919

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10 changes: 3 additions & 7 deletions llvm/lib/Target/X86/X86ISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -59360,7 +59360,8 @@ static SDValue combineINSERT_SUBVECTOR(SDNode *N, SelectionDAG &DAG,
}

// If we're splatting the lower half subvector of a full vector load into the
// upper half, attempt to create a subvector broadcast.
// upper half, just splat the subvector directly, potentially creating a
// subvector broadcast.
// TODO: Drop hasOneUse checks.
if ((int)IdxVal == (VecNumElts / 2) &&
Vec.getValueSizeInBits() == (2 * SubVec.getValueSizeInBits()) &&
Expand All @@ -59370,12 +59371,7 @@ static SDValue combineINSERT_SUBVECTOR(SDNode *N, SelectionDAG &DAG,
if (VecLd && SubLd &&
DAG.areNonVolatileConsecutiveLoads(
SubLd, VecLd, SubVec.getValueSizeInBits() / 8, 0)) {
SDValue BcastLd = getBROADCAST_LOAD(X86ISD::SUBV_BROADCAST_LOAD, dl, OpVT,
SubVecVT, SubLd, 0, DAG);
SDValue NewSubVec = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, SubVecVT,
BcastLd, DAG.getVectorIdxConstant(0, dl));
DCI.CombineTo(SubLd, NewSubVec, BcastLd.getValue(1));
return BcastLd;
return concatSubVectors(SubVec, SubVec, DAG, dl);
}
}

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