Index: lib/Transforms/InstCombine/InstCombineAndOrXor.cpp =================================================================== --- lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -2542,6 +2542,14 @@ if (match(Op0I, m_Xor(m_Value(A), m_Value(B))) && match(Op1I, m_And(m_Specific(A), m_Specific(B)))) return BinaryOperator::CreateOr(A, B); + // (A | ~B) ^ (~A ^ B) -> A & ~B + if (match(Op0I, m_Or(m_Value(A), m_Not(m_Value(B)))) && + match(Op1I, m_Xor(m_Not(m_Specific(A)), m_Specific(B)))) + return BinaryOperator::CreateAnd(A, Builder->CreateNot(B)); + // (B ^ ~A) ^ (~B | A) -> A & ~B + if (match(Op0I, m_Xor(m_Value(B), m_Not(m_Value(A)))) && + match(Op1I, m_Or(m_Not(m_Specific(B)), m_Specific(A)))) + return BinaryOperator::CreateAnd(A, Builder->CreateNot(B)); } // (A | B)^(~A) -> (A | ~B) Index: test/Transforms/InstCombine/or-xor.ll =================================================================== --- test/Transforms/InstCombine/or-xor.ll +++ test/Transforms/InstCombine/or-xor.ll @@ -160,3 +160,17 @@ ; CHECK-NEXT: %xor = xor i32 %x, %y ; CHECK-NEXT: ret i32 %xor } + +; ((x | ~y) ^ (~x ^ y)) -> (x & ~y) +define i32 @test18(i32 %x, i32 %y) { + %noty = xor i32 %y, -1 + %or = or i32 %x, %noty + %notx = xor i32 %x, -1 + %xor1 = xor i32 %notx, %y + %xor2 = xor i32 %or, %xor1 + ret i32 %xor2 +; CHECK-LABEL: @test18( +; CHECK-NEXT: %1 = xor i32 %y, -1 +; CHECK-NEXT: %xor2 = and i32 %x, %1 +; CHECK-NEXT: ret i32 %xor2 +}