+static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
+ ICmpInst *UnsignedICmp, bool IsAnd) {
+ Value *X, *Y;
+
+ ICmpInst::Predicate EqPred;
+ if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
+ !ICmpInst::isEquality(EqPred))
+ return nullptr;
+
+ ICmpInst::Predicate UnsignedPred;
+ if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
+ ICmpInst::isUnsigned(UnsignedPred))
+ ;
+ else if (match(UnsignedICmp,
+ m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
+ ICmpInst::isUnsigned(UnsignedPred))
+ UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
+ else
+ return nullptr;
+
+ // X < Y && Y != 0 --> X < Y
+ // X < Y || Y != 0 --> Y != 0
+ if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
+ return IsAnd ? UnsignedICmp : ZeroICmp;
+
+ // X >= Y || Y != 0 --> true
+ // X >= Y || Y == 0 --> X >= Y
+ if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
+ if (EqPred == ICmpInst::ICMP_NE)
+ return getTrue(UnsignedICmp->getType());
+ return UnsignedICmp;
+ }
+
+ // X < Y && Y == 0 --> false
+ if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
+ IsAnd)
+ return getFalse(UnsignedICmp->getType());
+
+ return nullptr;
+}
+