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IC: (X & C1) | C2 --> (X | C2) & (C1|C2)

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IC: (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)

We are now guaranteed that all 'or's will be inside of 'and's, and all 'and's
will be inside of 'xor's, if the second operands are constants.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7264 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-07-23 18:29:44 +00:00
parent 31a7f85346
commit ad44ebfff0
1 changed files with 26 additions and 1 deletions
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27
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -538,10 +538,35 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
return ReplaceInstUsesWith(I, Op0);
// or X, -1 == -1
if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1))
if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) {
if (RHS->isAllOnesValue())
return ReplaceInstUsesWith(I, Op1);
if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) {
// (X & C1) | C2 --> (X | C2) & (C1|C2)
if (Op0I->getOpcode() == Instruction::And && isOnlyUse(Op0))
if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
std::string Op0Name = Op0I->getName(); Op0I->setName("");
Instruction *Or = BinaryOperator::create(Instruction::Or,
Op0I->getOperand(0), RHS,
Op0Name);
InsertNewInstBefore(Or, I);
return BinaryOperator::create(Instruction::And, Or, *RHS | *Op0CI);
}
// (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)
if (Op0I->getOpcode() == Instruction::Xor && isOnlyUse(Op0))
if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
std::string Op0Name = Op0I->getName(); Op0I->setName("");
Instruction *Or = BinaryOperator::create(Instruction::Or,
Op0I->getOperand(0), RHS,
Op0Name);
InsertNewInstBefore(Or, I);
return BinaryOperator::create(Instruction::Xor, Or, *Op0CI & *~*RHS);
}
}
}
Value *Op0NotVal = dyn_castNotVal(Op0);
Value *Op1NotVal = dyn_castNotVal(Op1);