[llvm] [InstCombine] Fold (x + y) & (2^C) -> x & 2^C when y % 2^(C+1) == 0 (PR #157072)

[Yingwei Zheng via llvm-commits]

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@@ -2476,6 +2476,20 @@ Instruction *InstCombinerImpl::visitAnd(BinaryOperator &I) {
     return SelectInst::Create(Cmp, ConstantInt::getNullValue(Ty), Y);
   }
 
+  // (x + y) & (2^C) -> x & 2^C when y % 2^(C+1) == 0
+  if (match(Op0, m_Add(m_Value(X), m_Value(Y)))) {
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dtcxzyw wrote:

Please add a commuted test (i..e, `(x + y) & (2^C) -> y & 2^C when x % 2^(C+1) == 0`).

https://github.com/llvm/llvm-project/pull/157072