[llvm] f0c1a9a - [DAG] Add SDPatternMatch::m_Result to match a specific SDValue result (#145775)
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Thu Jun 26 09:38:26 PDT 2025
Author: Min-Yih Hsu
Date: 2025-06-26T22:08:22+05:30
New Revision: f0c1a9a85d1864aef23b3aa9157df1c48c9f2a5e
URL: https://github.com/llvm/llvm-project/commit/f0c1a9a85d1864aef23b3aa9157df1c48c9f2a5e
DIFF: https://github.com/llvm/llvm-project/commit/f0c1a9a85d1864aef23b3aa9157df1c48c9f2a5e.diff
LOG: [DAG] Add SDPatternMatch::m_Result to match a specific SDValue result (#145775)
`m_Result<N>` matches a SDValue that is the N-th result of the defining
SDNode. This is useful for creating a more fine-grained matching on
SDNode with multiple results.
-----
Inspired by #145481
Added:
Modified:
llvm/include/llvm/CodeGen/SDPatternMatch.h
llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/CodeGen/SDPatternMatch.h b/llvm/include/llvm/CodeGen/SDPatternMatch.h
index 9eb6dd45f912f..9228ccd433b27 100644
--- a/llvm/include/llvm/CodeGen/SDPatternMatch.h
+++ b/llvm/include/llvm/CodeGen/SDPatternMatch.h
@@ -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;
diff --git a/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp b/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
index 2b1fa75a1475a..e33fc30a7affe 100644
--- a/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
+++ b/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
@@ -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);
@@ -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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