+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;
+ }
+
+ return nullptr;
+}
+
+// Simplify (and (icmp ...) (icmp ...)) to true when we can tell that the range
+// of possible values cannot be satisfied.
+static Value *SimplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
+ ICmpInst::Predicate Pred0, Pred1;
+ ConstantInt *CI1, *CI2;
+ Value *V;
+
+ if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
+ return X;
+
+ if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
+ m_ConstantInt(CI2))))
+ return nullptr;
+
+ if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
+ return nullptr;
+
+ Type *ITy = Op0->getType();
+
+ auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
+ bool isNSW = AddInst->hasNoSignedWrap();
+ bool isNUW = AddInst->hasNoUnsignedWrap();
+
+ const APInt &CI1V = CI1->getValue();
+ const APInt &CI2V = CI2->getValue();
+ const APInt Delta = CI2V - CI1V;
+ if (CI1V.isStrictlyPositive()) {
+ if (Delta == 2) {
+ if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
+ return getFalse(ITy);
+ if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
+ return getFalse(ITy);
+ }
+ if (Delta == 1) {
+ if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
+ return getFalse(ITy);
+ if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
+ return getFalse(ITy);
+ }
+ }
+ if (CI1V.getBoolValue() && isNUW) {
+ if (Delta == 2)
+ if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
+ return getFalse(ITy);
+ if (Delta == 1)
+ if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
+ return getFalse(ITy);
+ }
+
+ return nullptr;
+}
+