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[DAG] Add SDPatternMatch::m_Result to match a specific SDValue result #145775

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Merged
merged 1 commit into from
Jun 26, 2025
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[DAG] Add SDPatternMatch::m_Result to match a specific SDValue result #145775

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17 changes: 17 additions & 0 deletions llvm/include/llvm/CodeGen/SDPatternMatch.h
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Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,23 @@ inline Value_match m_Specific(SDValue N) {
return Value_match(N);
}

template <unsigned ResNo, typename Pattern> struct Result_match {
Pattern P;

explicit Result_match(const Pattern &P) : P(P) {}

template <typename MatchContext>
bool match(const MatchContext &Ctx, SDValue N) {
return N.getResNo() == ResNo && P.match(Ctx, N);
}
};

/// Match only if the SDValue is a certain result at ResNo.
template <unsigned ResNo, typename Pattern>
inline Result_match<ResNo, Pattern> m_Result(const Pattern &P) {
return Result_match<ResNo, Pattern>(P);
}

struct DeferredValue_match {
SDValue &MatchVal;

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14 changes: 14 additions & 0 deletions llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
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Expand Up @@ -264,6 +264,11 @@ TEST_F(SelectionDAGPatternMatchTest, matchBinaryOp) {
SDValue Rotl = DAG->getNode(ISD::ROTL, DL, Int32VT, Op0, Op1);
SDValue Rotr = DAG->getNode(ISD::ROTR, DL, Int32VT, Op1, Op0);

SDValue SMulLoHi = DAG->getNode(ISD::SMUL_LOHI, DL,
DAG->getVTList(Int32VT, Int32VT), Op0, Op1);
SDValue PartsDiff =
DAG->getNode(ISD::SUB, DL, Int32VT, SMulLoHi, SMulLoHi.getValue(1));

SDValue ICMP_GT = DAG->getSetCC(DL, MVT::i1, Op0, Op1, ISD::SETGT);
SDValue ICMP_GE = DAG->getSetCC(DL, MVT::i1, Op0, Op1, ISD::SETGE);
SDValue ICMP_UGT = DAG->getSetCC(DL, MVT::i1, Op0, Op1, ISD::SETUGT);
Expand Down Expand Up @@ -347,6 +352,15 @@ TEST_F(SelectionDAGPatternMatchTest, matchBinaryOp) {
EXPECT_TRUE(sd_match(UMinLikeULT, m_UMinLike(m_Value(), m_Value())));
EXPECT_TRUE(sd_match(UMinLikeULE, m_UMinLike(m_Value(), m_Value())));

// By default, it matches any of the results.
EXPECT_TRUE(
sd_match(PartsDiff, m_Sub(m_Opc(ISD::SMUL_LOHI), m_Opc(ISD::SMUL_LOHI))));
// Matching a specific result.
EXPECT_TRUE(sd_match(PartsDiff, m_Sub(m_Opc(ISD::SMUL_LOHI),
m_Result<1>(m_Opc(ISD::SMUL_LOHI)))));
EXPECT_FALSE(sd_match(PartsDiff, m_Sub(m_Opc(ISD::SMUL_LOHI),
m_Result<0>(m_Opc(ISD::SMUL_LOHI)))));

SDValue BindVal;
EXPECT_TRUE(sd_match(SFAdd, m_ChainedBinOp(ISD::STRICT_FADD, m_Value(BindVal),
m_Deferred(BindVal))));
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