Index: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp =================================================================== --- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -2512,6 +2512,16 @@ if ((A == C && B == D) || (A == D && B == C)) return BinaryOperator::CreateXor(A, B); } + // (A | ~B) ^ (~A | B) -> A ^ B + if (match(Op0I, m_Or(m_Value(A), m_Not(m_Value(B)))) && + match(Op1I, m_Or(m_Not(m_Specific(A)), m_Specific(B)))) { + return BinaryOperator::CreateXor(A, B); + } + // (~A | B) ^ (A | ~B) -> A ^ B + if (match(Op0I, m_Or(m_Not(m_Value(A)), m_Value(B))) && + match(Op1I, m_Or(m_Specific(A), m_Not(m_Specific(B))))) { + return BinaryOperator::CreateXor(A, B); + } // (A ^ B)^(A | B) -> A & B if (match(Op0I, m_Xor(m_Value(A), m_Value(B))) && match(Op1I, m_Or(m_Value(C), m_Value(D)))) { Index: llvm/trunk/test/Transforms/InstCombine/or-xor.ll =================================================================== --- llvm/trunk/test/Transforms/InstCombine/or-xor.ll +++ llvm/trunk/test/Transforms/InstCombine/or-xor.ll @@ -147,3 +147,16 @@ ; CHECK-NEXT: %1 = and i32 %y, %x ; CHECK-NEXT: ret i32 %1 } + +; ((x | ~y) ^ (~x | y)) -> x ^ y +define i32 @test16(i32 %x, i32 %y) { + %noty = xor i32 %y, -1 + %notx = xor i32 %x, -1 + %or1 = or i32 %x, %noty + %or2 = or i32 %notx, %y + %xor = xor i32 %or1, %or2 + ret i32 %xor +; CHECK-LABEL: @test16( +; CHECK-NEXT: %xor = xor i32 %x, %y +; CHECK-NEXT: ret i32 %xor +}