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[X86] canonicalizeShuffleWithOp - don't bother trying to move shuffles across binops to fold the load. #126894

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Merged
merged 1 commit into from
Feb 12, 2025
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[X86] canonicalizeShuffleWithOp - don't bother trying to move shuffles across binops to fold the load. #126894

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9 changes: 3 additions & 6 deletions llvm/lib/Target/X86/X86ISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -41579,8 +41579,7 @@ static SDValue canonicalizeShuffleWithOp(SDValue N, SelectionDAG &DAG,
EVT ShuffleVT = N.getValueType();
unsigned Opc = N.getOpcode();

auto IsMergeableWithShuffle = [Opc, &DAG](SDValue Op, bool FoldShuf = true,
bool FoldLoad = false) {
auto IsMergeableWithShuffle = [Opc, &DAG](SDValue Op, bool FoldShuf = true) {
// AllZeros/AllOnes constants are freely shuffled and will peek through
// bitcasts. Other constant build vectors do not peek through bitcasts. Only
// merge with target shuffles if it has one use so shuffle combining is
Expand All @@ -41593,7 +41592,6 @@ static SDValue canonicalizeShuffleWithOp(SDValue N, SelectionDAG &DAG,
(Op.getOpcode() == Opc && Op->hasOneUse()) ||
(Op.getOpcode() == ISD::INSERT_SUBVECTOR && Op->hasOneUse()) ||
(FoldShuf && isTargetShuffle(Op.getOpcode()) && Op->hasOneUse()) ||
(FoldLoad && isShuffleFoldableLoad(Op)) ||
DAG.isSplatValue(Op, /*AllowUndefs*/ false);
};
auto IsSafeToMoveShuffle = [ShuffleVT](SDValue Op, unsigned BinOp) {
Expand Down Expand Up @@ -41629,9 +41627,8 @@ static SDValue canonicalizeShuffleWithOp(SDValue N, SelectionDAG &DAG,
SDValue Op00 = peekThroughOneUseBitcasts(N0.getOperand(0));
SDValue Op01 = peekThroughOneUseBitcasts(N0.getOperand(1));
bool FoldShuf = Opc != X86ISD::VPERMI;
bool FoldLoad = Opc != X86ISD::PSHUFB;
if (IsMergeableWithShuffle(Op00, FoldShuf, FoldLoad) ||
IsMergeableWithShuffle(Op01, FoldShuf, FoldLoad)) {
if (IsMergeableWithShuffle(Op00, FoldShuf) ||
IsMergeableWithShuffle(Op01, FoldShuf)) {
SDValue LHS, RHS;
Op00 = DAG.getBitcast(ShuffleVT, Op00);
Op01 = DAG.getBitcast(ShuffleVT, Op01);
Expand Down