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Fold A^(B&A) -> (B&A)^A

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Fold (B&A)^A == ~B & A

This implements InstCombine/xor.ll:test2[56]

llvm-svn: 27328
This commit is contained in:
Chris Lattner 2006-04-01 08:03:55 +00:00
parent bce001c462
commit 497bbd4650
1 changed files with 46 additions and 7 deletions
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53
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -2508,6 +2508,30 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
if (match(Op1, m_Or(m_Value(A), m_Value(B))))
if (A == Op0 || B == Op0) // A & (A | ?) --> A
return ReplaceInstUsesWith(I, Op0);
if (Op0->hasOneUse() &&
match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
if (A == Op1) { // (A^B)&A -> A&(A^B)
I.swapOperands(); // Simplify below
std::swap(Op0, Op1);
} else if (B == Op1) { // (A^B)&B -> B&(B^A)
cast<BinaryOperator>(Op0)->swapOperands();
I.swapOperands(); // Simplify below
std::swap(Op0, Op1);
}
}
if (Op1->hasOneUse() &&
match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
if (B == Op0) { // B&(A^B) -> B&(B^A)
cast<BinaryOperator>(Op1)->swapOperands();
std::swap(A, B);
}
if (A == Op0) { // A&(A^B) -> A & ~B
Instruction *NotB = BinaryOperator::createNot(B, "tmp");
InsertNewInstBefore(NotB, I);
return BinaryOperator::createAnd(A, NotB);
}
}
}
@ -2943,14 +2967,14 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
return ReplaceInstUsesWith(I,
ConstantIntegral::getAllOnesValue(I.getType()));
if (Instruction *Op1I = dyn_cast<Instruction>(Op1))
if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1))
if (Op1I->getOpcode() == Instruction::Or) {
if (Op1I->getOperand(0) == Op0) { // B^(B|A) == (A|B)^B
cast<BinaryOperator>(Op1I)->swapOperands();
Op1I->swapOperands();
I.swapOperands();
std::swap(Op0, Op1);
} else if (Op1I->getOperand(1) == Op0) { // B^(A|B) == (A|B)^B
I.swapOperands();
I.swapOperands(); // Simplified below.
std::swap(Op0, Op1);
}
} else if (Op1I->getOpcode() == Instruction::Xor) {
@ -2958,15 +2982,22 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
return ReplaceInstUsesWith(I, Op1I->getOperand(1));
else if (Op0 == Op1I->getOperand(1)) // A^(B^A) == B
return ReplaceInstUsesWith(I, Op1I->getOperand(0));
} else if (Op1I->getOpcode() == Instruction::And && Op1I->hasOneUse()) {
if (Op1I->getOperand(0) == Op0) // A^(A&B) -> A^(B&A)
Op1I->swapOperands();
if (Op0 == Op1I->getOperand(1)) { // A^(B&A) -> (B&A)^A
I.swapOperands(); // Simplified below.
std::swap(Op0, Op1);
}
}
if (Instruction *Op0I = dyn_cast<Instruction>(Op0))
if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0))
if (Op0I->getOpcode() == Instruction::Or && Op0I->hasOneUse()) {
if (Op0I->getOperand(0) == Op1) // (B|A)^B == (A|B)^B
cast<BinaryOperator>(Op0I)->swapOperands();
Op0I->swapOperands();
if (Op0I->getOperand(1) == Op1) { // (A|B)^B == A & ~B
Value *NotB = InsertNewInstBefore(BinaryOperator::createNot(Op1,
Op1->getName()+".not"), I);
Instruction *NotB = BinaryOperator::createNot(Op1, "tmp");
InsertNewInstBefore(NotB, I);
return BinaryOperator::createAnd(Op0I->getOperand(0), NotB);
}
} else if (Op0I->getOpcode() == Instruction::Xor) {
@ -2974,6 +3005,14 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
return ReplaceInstUsesWith(I, Op0I->getOperand(1));
else if (Op1 == Op0I->getOperand(1)) // (B^A)^A == B
return ReplaceInstUsesWith(I, Op0I->getOperand(0));
} else if (Op0I->getOpcode() == Instruction::And && Op0I->hasOneUse()) {
if (Op0I->getOperand(0) == Op1) // (A&B)^A -> (B&A)^A
Op0I->swapOperands();
if (Op0I->getOperand(1) == Op1) { // (B&A)^A == ~B & A
Instruction *N = BinaryOperator::createNot(Op0I->getOperand(0), "tmp");
InsertNewInstBefore(N, I);
return BinaryOperator::createAnd(N, Op1);
}
}
// (setcc1 A, B) ^ (setcc2 A, B) --> (setcc3 A, B)