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InstCombine: (X ^ 4) == 8 --> X == 12

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7260 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-07-23 17:26:36 +00:00
parent 347319a4c9
commit 00b1a7e23e
1 changed files with 6 additions and 1 deletions
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7
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -711,7 +711,7 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) {
return BinaryOperator::createNot(Val, I.getName());
}
// If the first operand is (and|or) with a constant, and the second
// If the first operand is (and|or|xor) with a constant, and the second
// operand is a constant, simplify a bit.
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0))
if (ConstantInt *BOC = dyn_cast<ConstantInt>(BO->getOperand(1)))
@ -725,6 +725,11 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) {
// comparison can never succeed!
if (!(*CI & *~*BOC)->isNullValue())
return ReplaceInstUsesWith(I, ConstantBool::get(isSetNE));
} else if (BO->getOpcode() == Instruction::Xor) {
// For the xor case, we can always just xor the two constants
// together, potentially eliminating the explicit xor.
return BinaryOperator::create(I.getOpcode(), BO->getOperand(0),
*CI ^ *BOC);
}
}