[llvm] Fujun.han/instcombine or to xor (PR #75129)

[Yingwei Zheng via llvm-commits]

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@@ -3343,6 +3343,27 @@ Instruction *InstCombinerImpl::visitOr(BinaryOperator &I) {
   if (Instruction *X = foldComplexAndOrPatterns(I, Builder))
     return X;
 
+  // Change (or (and (add x, half_c1), c3), (and x, c2)) to (xor x, half_c1),
+  // iff c1, c2, c3 is constant, and half_c1 = (lshr c1, 1),  and c1 is pow2,
+  // and c2 < c1, and c3 == (c1 - 1) ^ c2, and (c1 >> 1) & c3 == (c1 >> 1) and x
+  // is known to be less than c1.
+  Type *Ty = I.getType();
+  if (Ty->isIntegerTy()) {
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dtcxzyw wrote:

It also holds for vectors.
```suggestion
  
```

https://github.com/llvm/llvm-project/pull/75129