[llvm] [InstCombine] Canonicalize `icmp eq/ne (A ^ C), B` to `icmp eq/ne (A ^ B), C` (PR #67273)

[Nikita Popov via llvm-commits]

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@@ -5437,6 +5437,15 @@ Instruction *InstCombinerImpl::foldICmpEquality(ICmpInst &I) {
         Pred, A,
         Builder.CreateIntrinsic(Op0->getType(), Intrinsic::fshl, {A, A, B}));
 
+  // Canonicalize:
+  // icmp eq/ne OneUse(A ^ Cst), B --> icmp eq/ne (A ^ B), Cst
+  Constant *Cst;
+  if (match(&I, m_c_ICmp(PredUnused,
+                         m_OneUse(m_Xor(m_Value(A), m_ImmConstant(Cst))),
+                         m_Value(B))))
+    return ICmpInst::Create(Instruction::ICmp, Pred, Builder.CreateXor(A, B),
+                            Cst);
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nikic wrote:

Use `new ICmpInst` instead.

https://github.com/llvm/llvm-project/pull/67273