Index: lib/Transforms/InstCombine/InstCombineAndOrXor.cpp =================================================================== --- lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -2508,6 +2508,34 @@ if ((A == C && B == D) || (A == D && B == C)) return BinaryOperator::CreateXor(A, B); } + // (A | ~B) ^ (~A | B) -> A ^ B + // (A | ~B) ^ (B | ~A) -> 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))) || + match(Op1I, m_Or(m_Specific(B), m_Not(m_Specific(A)))))) { + return BinaryOperator::CreateXor(A, B); + } + // (~B | A) ^ (~A | B) -> A ^ B + // (~B | A) ^ (B | ~A) -> A ^ B + if (match(Op0I, m_Or(m_Not(m_Value(B)), m_Value(A))) && + (match(Op1I, m_Or(m_Not(m_Specific(A)), m_Specific(B))) || + match(Op1I, m_Or(m_Specific(B), m_Not(m_Specific(A)))))) { + return BinaryOperator::CreateXor(A, B); + } + // (~A | B) ^ (A | ~B) -> A ^ B + // (~A | B) ^ (~B | A) -> 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)))) || + match(Op1I, m_Or(m_Not(m_Specific(B)), m_Specific(A))))) { + return BinaryOperator::CreateXor(A, B); + } + // (B | ~A) ^ (A | ~B) -> A ^ B + // (B | ~A) ^ (~B | A) -> A ^ B + if (match(Op0I, m_Or(m_Value(B), m_Not(m_Value(A)))) && + (match(Op1I, m_Or(m_Specific(A), m_Not(m_Specific(B)))) || + match(Op1I, m_Or(m_Not(m_Specific(B)), m_Specific(A))))) { + 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: test/Transforms/InstCombine/or-xor.ll =================================================================== --- test/Transforms/InstCombine/or-xor.ll +++ 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) { + %1 = xor i32 %y, -1 + %2 = xor i32 %x, -1 + %3 = or i32 %x, %1 + %4 = or i32 %2, %y + %5 = xor i32 %3, %4 + ret i32 %5 +; CHECK-LABEL: @test16( +; CHECK-NEXT: %1 = xor i32 %x, %y +; CHECK-NEXT: ret i32 %1 +}