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Implement two xforms:
1. ~(~X | Y) === (X & ~Y) 2. (A|B) & ~(A&B) -> A^B This allows us to transform ~(~(a|b) | (a&b)) -> a^b. This implements PR1510 for scalar values. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37584 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -3363,14 +3363,29 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
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}
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}
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{
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{
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Value *A = 0, *B = 0;
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Value *A = 0, *B = 0, *C = 0, *D = 0;
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if (match(Op0, m_Or(m_Value(A), m_Value(B))))
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if (match(Op0, m_Or(m_Value(A), m_Value(B)))) {
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if (A == Op1 || B == Op1) // (A | ?) & A --> A
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if (A == Op1 || B == Op1) // (A | ?) & A --> A
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return ReplaceInstUsesWith(I, Op1);
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return ReplaceInstUsesWith(I, Op1);
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if (match(Op1, m_Or(m_Value(A), m_Value(B))))
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// (A|B) & ~(A&B) -> A^B
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if (match(Op1, m_Not(m_And(m_Value(C), m_Value(D))))) {
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if ((A == C && B == D) || (A == D && B == C))
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return BinaryOperator::createXor(A, B);
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}
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}
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if (match(Op1, m_Or(m_Value(A), m_Value(B)))) {
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if (A == Op0 || B == Op0) // A & (A | ?) --> A
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if (A == Op0 || B == Op0) // A & (A | ?) --> A
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return ReplaceInstUsesWith(I, Op0);
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return ReplaceInstUsesWith(I, Op0);
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// ~(A&B) & (A|B) -> A^B
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if (match(Op0, m_Not(m_And(m_Value(C), m_Value(D))))) {
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if ((A == C && B == D) || (A == D && B == C))
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return BinaryOperator::createXor(A, B);
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}
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}
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if (Op0->hasOneUse() &&
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if (Op0->hasOneUse() &&
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match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
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match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
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if (A == Op1) { // (A^B)&A -> A&(A^B)
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if (A == Op1) { // (A^B)&A -> A&(A^B)
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@ -4137,15 +4152,20 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
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return BinaryOperator::createAdd(Op0I->getOperand(1), ConstantRHS);
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return BinaryOperator::createAdd(Op0I->getOperand(1), ConstantRHS);
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}
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}
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// ~(~X & Y) --> (X | ~Y)
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// ~(~X & Y) --> (X | ~Y) - De Morgan's Law
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if (Op0I->getOpcode() == Instruction::And && RHS->isAllOnesValue()) {
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// ~(~X | Y) === (X & ~Y) - De Morgan's Law
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if ((Op0I->getOpcode() == Instruction::And ||
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Op0I->getOpcode() == Instruction::Or) && RHS->isAllOnesValue()) {
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if (dyn_castNotVal(Op0I->getOperand(1))) Op0I->swapOperands();
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if (dyn_castNotVal(Op0I->getOperand(1))) Op0I->swapOperands();
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if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) {
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if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) {
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Instruction *NotY =
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Instruction *NotY =
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BinaryOperator::createNot(Op0I->getOperand(1),
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BinaryOperator::createNot(Op0I->getOperand(1),
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Op0I->getOperand(1)->getName()+".not");
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Op0I->getOperand(1)->getName()+".not");
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InsertNewInstBefore(NotY, I);
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InsertNewInstBefore(NotY, I);
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if (Op0I->getOpcode() == Instruction::And)
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return BinaryOperator::createOr(Op0NotVal, NotY);
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return BinaryOperator::createOr(Op0NotVal, NotY);
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else
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return BinaryOperator::createAnd(Op0NotVal, NotY);
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}
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}
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}
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}
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