- // If a bit is known to be zero for A and known to be one for B,
- // then A and B cannot be equal.
- if (ICmpInst::isEquality(Pred)) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
- uint32_t BitWidth = CI->getBitWidth();
- APInt LHSKnownZero(BitWidth, 0);
- APInt LHSKnownOne(BitWidth, 0);
- computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL,
- 0, Q.AT, Q.CxtI, Q.DT);
- APInt RHSKnownZero(BitWidth, 0);
- APInt RHSKnownOne(BitWidth, 0);
- computeKnownBits(RHS, RHSKnownZero, RHSKnownOne, Q.DL,
- 0, Q.AT, Q.CxtI, Q.DT);
- if (((LHSKnownOne & RHSKnownZero) != 0) ||
- ((LHSKnownZero & RHSKnownOne) != 0))
- return (Pred == ICmpInst::ICMP_EQ)
- ? ConstantInt::getFalse(CI->getContext())
- : ConstantInt::getTrue(CI->getContext());
- }
- }
-