Index: lib/Transforms/InstCombine/InstCombineAndOrXor.cpp =================================================================== --- lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -2143,6 +2143,16 @@ return BinaryOperator::CreateOr(Not, Op0); } + // (A & B) | ((~A) ^ B) -> (~A ^ B) + if (match(Op0, m_And(m_Value(A), m_Value(B))) && + match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B)))) + return BinaryOperator::CreateXor(Builder->CreateNot(A), B); + + // ((~A) ^ B) | (A & B) -> (~A ^ B) + if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) && + match(Op1, m_And(m_Specific(A), m_Specific(B)))) + return BinaryOperator::CreateXor(Builder->CreateNot(A), B); + if (SwappedForXor) std::swap(Op0, Op1); Index: test/Transforms/InstCombine/or.ll =================================================================== --- test/Transforms/InstCombine/or.ll +++ test/Transforms/InstCombine/or.ll @@ -427,3 +427,25 @@ %or = or i32 %and, %xor ret i32 %or } + +define i32 @test43(i32 %a, i32 %b) { +; CHECK-LABEL: test43( +; CHECK-NEXT: %1 = xor i32 %a, -1 +; CHECK-NEXT: %or = xor i32 %1, %b + %and = and i32 %a, %b + %nega = xor i32 %a, -1 + %xor = xor i32 %nega, %b + %or = or i32 %and, %xor + ret i32 %or +} + +define i32 @test44(i32 %a, i32 %b) { +; CHECK-LABEL: test44( +; CHECK-NEXT: %1 = xor i32 %a, -1 +; CHECK-NEXT: %or = xor i32 %1, %b + %nega = xor i32 %a, -1 + %xor = xor i32 %nega, %b + %and = and i32 %a, %b + %or = or i32 %xor, %and + ret i32 %or +}