switch (I->getOpcode()) {
case Instruction::And:
// (X & C1) & C2 == 0 iff C1 & C2 == 0.
- if (ConstantIntegral *CI = dyn_cast<ConstantIntegral>(I->getOperand(1)))
- if (ConstantExpr::getAnd(CI, Mask)->isNullValue())
+ if (ConstantIntegral *CI = dyn_cast<ConstantIntegral>(I->getOperand(1))) {
+ ConstantIntegral *C1C2 =
+ cast<ConstantIntegral>(ConstantExpr::getAnd(CI, Mask));
+ if (MaskedValueIsZero(I->getOperand(0), C1C2))
return true;
- break;
+ }
+ // If either the LHS or the RHS are MaskedValueIsZero, the result is zero.
+ return MaskedValueIsZero(I->getOperand(1), Mask) ||
+ MaskedValueIsZero(I->getOperand(0), Mask);
case Instruction::Or:
+ case Instruction::Xor:
// If the LHS and the RHS are MaskedValueIsZero, the result is also zero.
return MaskedValueIsZero(I->getOperand(1), Mask) &&
MaskedValueIsZero(I->getOperand(0), Mask);