diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index bab6616deda..546f0f2709d 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -3363,13 +3363,28 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) { } { - Value *A = 0, *B = 0; - if (match(Op0, m_Or(m_Value(A), m_Value(B)))) + Value *A = 0, *B = 0, *C = 0, *D = 0; + if (match(Op0, m_Or(m_Value(A), m_Value(B)))) { if (A == Op1 || B == Op1) // (A | ?) & A --> A return ReplaceInstUsesWith(I, Op1); - if (match(Op1, m_Or(m_Value(A), m_Value(B)))) + + // (A|B) & ~(A&B) -> A^B + if (match(Op1, m_Not(m_And(m_Value(C), m_Value(D))))) { + if ((A == C && B == D) || (A == D && B == C)) + return BinaryOperator::createXor(A, B); + } + } + + if (match(Op1, m_Or(m_Value(A), m_Value(B)))) { if (A == Op0 || B == Op0) // A & (A | ?) --> A return ReplaceInstUsesWith(I, Op0); + + // ~(A&B) & (A|B) -> A^B + if (match(Op0, m_Not(m_And(m_Value(C), m_Value(D))))) { + if ((A == C && B == D) || (A == D && B == C)) + return BinaryOperator::createXor(A, B); + } + } if (Op0->hasOneUse() && match(Op0, m_Xor(m_Value(A), m_Value(B)))) { @@ -4137,15 +4152,20 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) { return BinaryOperator::createAdd(Op0I->getOperand(1), ConstantRHS); } - // ~(~X & Y) --> (X | ~Y) - if (Op0I->getOpcode() == Instruction::And && RHS->isAllOnesValue()) { + // ~(~X & Y) --> (X | ~Y) - De Morgan's Law + // ~(~X | Y) === (X & ~Y) - De Morgan's Law + if ((Op0I->getOpcode() == Instruction::And || + Op0I->getOpcode() == Instruction::Or) && RHS->isAllOnesValue()) { if (dyn_castNotVal(Op0I->getOperand(1))) Op0I->swapOperands(); if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) { Instruction *NotY = BinaryOperator::createNot(Op0I->getOperand(1), Op0I->getOperand(1)->getName()+".not"); InsertNewInstBefore(NotY, I); - return BinaryOperator::createOr(Op0NotVal, NotY); + if (Op0I->getOpcode() == Instruction::And) + return BinaryOperator::createOr(Op0NotVal, NotY); + else + return BinaryOperator::createAnd(Op0NotVal, NotY); } }