commit 0a33532500a90668f5cfe485134e9c9c388d3614
author goldsteinn <35538541+goldsteinn@users.noreply.github.com> Sat Jan 18 11:23:01 2025 -0600
committer GitHub <noreply@github.com> Sat Jan 18 11:23:01 2025 -0600
tree 04e32e4d804618ea09b013f9fe26b4c32db78a1d
parent bc386a82686d5f40f9f7325cc41aadc43f09cc79

[PatternMatch] Add `m_c_XorLike` matcher; NFC (#122642)

`m_c_XorLike` matches either:
    `(xor L, R)`, `(xor R, L)`, or `(sub nuw R, L)` iff `R.isMask()`.

This is in preperation for dropping the fold from:
    `(sub C_Mask, X)` -> `(xor X, C_Mask)`

llvm/unittests/IR/PatternMatch.cpp

diff --git a/llvm/unittests/IR/PatternMatch.cpp b/llvm/unittests/IR/PatternMatch.cpp
index 47fde57..d06ada5 100644
--- a/llvm/unittests/IR/PatternMatch.cpp
+++ b/llvm/unittests/IR/PatternMatch.cpp
@@ -533,6 +533,72 @@
   EXPECT_FALSE(m_c_BitwiseLogic(m_Zero(), m_Zero()).match(Xor));
 }
 
+TEST_F(PatternMatchTest, XorLike) {
+  Value *AllocaX = IRB.CreateAlloca(IRB.getInt32Ty());
+  Value *X = IRB.CreateLoad(IRB.getInt32Ty(), AllocaX);
+  Value *AllocaY = IRB.CreateAlloca(IRB.getInt32Ty());
+  Value *Y = IRB.CreateLoad(IRB.getInt32Ty(), AllocaY);
+  Value *MaskC = IRB.getInt32(31);
+  Value *NonMaskC = IRB.getInt32(32);
+
+  Value *OpA, *OpB;
+  {
+    Value *Xor = IRB.CreateXor(X, Y);
+    Value *Sub = IRB.CreateNUWSub(X, Y);
+    OpA = nullptr;
+    OpB = nullptr;
+    EXPECT_TRUE(m_c_XorLike(m_Value(OpA), m_Value(OpB)).match(Xor));
+    EXPECT_TRUE(OpA != OpB && (OpA == X || OpB == X) && (OpA == Y || OpB == Y));
+    OpA = nullptr;
+    OpB = nullptr;
+    EXPECT_FALSE(m_c_XorLike(m_Value(OpA), m_Value(OpB)).match(Sub));
+  }
+  {
+    Value *Xor = IRB.CreateXor(X, MaskC);
+    Value *Sub = IRB.CreateNUWSub(MaskC, X);
+    OpA = nullptr;
+    OpB = nullptr;
+    EXPECT_TRUE(m_c_XorLike(m_Value(OpA), m_Value(OpB)).match(Xor));
+    EXPECT_TRUE(OpA != OpB && (OpA == X || OpB == X) &&
+                (OpA == MaskC || OpB == MaskC));
+    OpA = nullptr;
+    OpB = nullptr;
+    EXPECT_TRUE(m_c_XorLike(m_Value(OpA), m_Value(OpB)).match(Sub));
+    EXPECT_TRUE(OpA != OpB && (OpA == X || OpB == X) &&
+                (OpA == MaskC || OpB == MaskC));
+  }
+  {
+    Value *Xor = IRB.CreateXor(X, MaskC);
+    Value *Sub = IRB.CreateNSWSub(MaskC, X);
+    OpA = nullptr;
+    OpB = nullptr;
+    EXPECT_TRUE(m_c_XorLike(m_Value(OpA), m_Value(OpB)).match(Xor));
+    EXPECT_TRUE(OpA != OpB && (OpA == X || OpB == X) &&
+                (OpA == MaskC || OpB == MaskC));
+    OpA = nullptr;
+    OpB = nullptr;
+    EXPECT_FALSE(m_c_XorLike(m_Value(OpA), m_Value(OpB)).match(Sub));
+  }
+  {
+    Value *Sub = IRB.CreateNUWSub(X, MaskC);
+    OpA = nullptr;
+    OpB = nullptr;
+    EXPECT_FALSE(m_c_XorLike(m_Value(OpA), m_Value(OpB)).match(Sub));
+  }
+  {
+    Value *Xor = IRB.CreateXor(X, NonMaskC);
+    Value *Sub = IRB.CreateNUWSub(NonMaskC, X);
+    OpA = nullptr;
+    OpB = nullptr;
+    EXPECT_TRUE(m_c_XorLike(m_Value(OpA), m_Value(OpB)).match(Xor));
+    EXPECT_TRUE(OpA != OpB && (OpA == X || OpB == X) &&
+                (OpA == NonMaskC || OpB == NonMaskC));
+    OpA = nullptr;
+    OpB = nullptr;
+    EXPECT_FALSE(m_c_XorLike(m_Value(OpA), m_Value(OpB)).match(Sub));
+  }
+}
+
 TEST_F(PatternMatchTest, ZExtSExtSelf) {
   LLVMContext &Ctx = IRB.getContext();