Index: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp =================================================================== --- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -2454,6 +2454,14 @@ if ((A == C && B == D) || (A == D && B == C)) return BinaryOperator::CreateXor(A, B); } + // (A & B) ^ (A ^ B) -> (A | B) + if (match(Op0I, m_And(m_Value(A), m_Value(B))) && + match(Op1I, m_Xor(m_Specific(A), m_Specific(B)))) + return BinaryOperator::CreateOr(A, B); + // (A ^ B) ^ (A & B) -> (A | B) + 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) -> (A | ~B) Index: llvm/trunk/test/Transforms/InstCombine/xor2.ll =================================================================== --- llvm/trunk/test/Transforms/InstCombine/xor2.ll +++ llvm/trunk/test/Transforms/InstCombine/xor2.ll @@ -105,3 +105,23 @@ ; CHECK-NEXT: %1 = xor i32 %b, -1 ; CHECK-NEXT: %xor = or i32 %a, %1 } + +; (A & B) ^ (A ^ B) -> (A | B) +define i32 @test9(i32 %b, i32 %c) { + %and = and i32 %b, %c + %xor = xor i32 %b, %c + %xor2 = xor i32 %and, %xor + ret i32 %xor2 +; CHECK-LABEL: @test9( +; CHECK-NEXT: %xor2 = or i32 %b, %c +} + +; (A ^ B) ^ (A & B) -> (A | B) +define i32 @test10(i32 %b, i32 %c) { + %xor = xor i32 %b, %c + %and = and i32 %b, %c + %xor2 = xor i32 %xor, %and + ret i32 %xor2 +; CHECK-LABEL: @test10( +; CHECK-NEXT: %xor2 = or i32 %b, %c +}