[llvm] [PatternMatch] Fix matching order for `m_c_Intrinsic` (PR #166047)

[Yingwei Zheng via llvm-commits]

https://github.com/dtcxzyw updated https://github.com/llvm/llvm-project/pull/166047

>From 2334872d26b1557019c513f07dd3dc620e1429e7 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Sun, 2 Nov 2025 15:55:45 +0800
Subject: [PATCH 1/2] [PatternMatch] Fix matching order for

---
 llvm/include/llvm/IR/PatternMatch.h | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/IR/PatternMatch.h b/llvm/include/llvm/IR/PatternMatch.h
index e3ec7e1764da7..54f9c28dcbf97 100644
--- a/llvm/include/llvm/IR/PatternMatch.h
+++ b/llvm/include/llvm/IR/PatternMatch.h
@@ -3069,12 +3069,28 @@ m_c_MaxOrMin(const LHS &L, const RHS &R) {
                      m_CombineOr(m_c_UMax(L, R), m_c_UMin(L, R)));
 }
 
+template <Intrinsic::ID IntrID, typename LHS, typename RHS>
+struct CommutativeBinaryIntrinsic_match {
+  unsigned ID;
+  LHS L;
+  RHS R;
+
+  CommutativeBinaryIntrinsic_match(const LHS &L, const RHS &R)
+      : ID(IntrID), L(L), R(R) {}
+
+  template <typename OpTy> bool match(OpTy *V) const {
+    const auto *II = dyn_cast<IntrinsicInst>(V);
+    if (!II || II->getIntrinsicID() != ID)
+      return false;
+    return (L.match(II->getArgOperand(0)) && R.match(II->getArgOperand(1))) ||
+           (L.match(II->getArgOperand(1)) && R.match(II->getArgOperand(0)));
+  }
+};
+
 template <Intrinsic::ID IntrID, typename T0, typename T1>
-inline match_combine_or<typename m_Intrinsic_Ty<T0, T1>::Ty,
-                        typename m_Intrinsic_Ty<T1, T0>::Ty>
+inline CommutativeBinaryIntrinsic_match<IntrID, T0, T1>
 m_c_Intrinsic(const T0 &Op0, const T1 &Op1) {
-  return m_CombineOr(m_Intrinsic<IntrID>(Op0, Op1),
-                     m_Intrinsic<IntrID>(Op1, Op0));
+  return CommutativeBinaryIntrinsic_match<IntrID, T0, T1>(Op0, Op1);
 }
 
 /// Matches FAdd with LHS and RHS in either order.

>From c9de923a34e608ce2dfbda94757266367cf96901 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Fri, 7 Nov 2025 00:08:41 +0800
Subject: [PATCH 2/2] [PatternMatch] Add a unit test

---
 llvm/include/llvm/IR/PatternMatch.h |  6 ++----
 llvm/unittests/IR/PatternMatch.cpp  | 27 +++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/IR/PatternMatch.h b/llvm/include/llvm/IR/PatternMatch.h
index 54f9c28dcbf97..bb3d7fff5c9bc 100644
--- a/llvm/include/llvm/IR/PatternMatch.h
+++ b/llvm/include/llvm/IR/PatternMatch.h
@@ -3071,16 +3071,14 @@ m_c_MaxOrMin(const LHS &L, const RHS &R) {
 
 template <Intrinsic::ID IntrID, typename LHS, typename RHS>
 struct CommutativeBinaryIntrinsic_match {
-  unsigned ID;
   LHS L;
   RHS R;
 
-  CommutativeBinaryIntrinsic_match(const LHS &L, const RHS &R)
-      : ID(IntrID), L(L), R(R) {}
+  CommutativeBinaryIntrinsic_match(const LHS &L, const RHS &R) : L(L), R(R) {}
 
   template <typename OpTy> bool match(OpTy *V) const {
     const auto *II = dyn_cast<IntrinsicInst>(V);
-    if (!II || II->getIntrinsicID() != ID)
+    if (!II || II->getIntrinsicID() != IntrID)
       return false;
     return (L.match(II->getArgOperand(0)) && R.match(II->getArgOperand(1))) ||
            (L.match(II->getArgOperand(1)) && R.match(II->getArgOperand(0)));
diff --git a/llvm/unittests/IR/PatternMatch.cpp b/llvm/unittests/IR/PatternMatch.cpp
index 972dac82d3331..1142c559c97f8 100644
--- a/llvm/unittests/IR/PatternMatch.cpp
+++ b/llvm/unittests/IR/PatternMatch.cpp
@@ -2657,4 +2657,31 @@ TEST_F(PatternMatchTest, ShiftOrSelf) {
   EXPECT_EQ(ShAmtC, 0U);
 }
 
+TEST_F(PatternMatchTest, CommutativeDeferredIntrinsicMatch) {
+  Value *X = ConstantFP::get(IRB.getDoubleTy(), 1.0);
+  Value *Y = ConstantFP::get(IRB.getDoubleTy(), 2.0);
+
+  auto CheckMatch = [X, Y](Value *Pattern) {
+    Value *tX = nullptr, *tY = nullptr;
+    EXPECT_TRUE(
+        match(Pattern, m_c_Intrinsic<Intrinsic::minimum>(
+                           m_Value(tX), m_c_Intrinsic<Intrinsic::minimum>(
+                                            m_Deferred(tX), m_Value(tY)))));
+    EXPECT_EQ(tX, X);
+    EXPECT_EQ(tY, Y);
+  };
+  CheckMatch(IRB.CreateBinaryIntrinsic(
+      Intrinsic::minimum, X,
+      IRB.CreateBinaryIntrinsic(Intrinsic::minimum, X, Y)));
+  CheckMatch(IRB.CreateBinaryIntrinsic(
+      Intrinsic::minimum, X,
+      IRB.CreateBinaryIntrinsic(Intrinsic::minimum, Y, X)));
+  CheckMatch(IRB.CreateBinaryIntrinsic(
+      Intrinsic::minimum, IRB.CreateBinaryIntrinsic(Intrinsic::minimum, X, Y),
+      X));
+  CheckMatch(IRB.CreateBinaryIntrinsic(
+      Intrinsic::minimum, IRB.CreateBinaryIntrinsic(Intrinsic::minimum, Y, X),
+      X));
+}
+
 } // anonymous namespace.