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[DAGCombiner] Remove unneeded m_BitReverse from visitBITREVERSE. NFC (#168918)

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We already know we're looking at BITREVERSE, we can match on the source
operand.
This commit is contained in:
Craig Topper 2025-11-20 10:20:47 -08:00 committed by GitHub
parent 6d52efca67
commit 01e5e4fd00
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1 changed files with 2 additions and 2 deletions
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4
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -11763,12 +11763,12 @@ SDValue DAGCombiner::visitBITREVERSE(SDNode *N) {
// fold (bitreverse (lshr (bitreverse x), y)) -> (shl x, y)
if ((!LegalOperations || TLI.isOperationLegal(ISD::SHL, VT)) &&
sd_match(N, m_BitReverse(m_Srl(m_BitReverse(m_Value(X)), m_Value(Y)))))
sd_match(N0, m_Srl(m_BitReverse(m_Value(X)), m_Value(Y))))
return DAG.getNode(ISD::SHL, DL, VT, X, Y);
// fold (bitreverse (shl (bitreverse x), y)) -> (lshr x, y)
if ((!LegalOperations || TLI.isOperationLegal(ISD::SRL, VT)) &&
sd_match(N, m_BitReverse(m_Shl(m_BitReverse(m_Value(X)), m_Value(Y)))))
sd_match(N0, m_Shl(m_BitReverse(m_Value(X)), m_Value(Y))))
return DAG.getNode(ISD::SRL, DL, VT, X, Y);
return SDValue();