+ // icmp pred (or X, Y), X
+ if (LBO && match(LBO, m_CombineOr(m_Or(m_Value(), m_Specific(RHS)),
+ m_Or(m_Specific(RHS), m_Value())))) {
+ if (Pred == ICmpInst::ICMP_ULT)
+ return getFalse(ITy);
+ if (Pred == ICmpInst::ICMP_UGE)
+ return getTrue(ITy);
+ }
+ // icmp pred X, (or X, Y)
+ if (RBO && match(RBO, m_CombineOr(m_Or(m_Value(), m_Specific(LHS)),
+ m_Or(m_Specific(LHS), m_Value())))) {
+ if (Pred == ICmpInst::ICMP_ULE)
+ return getTrue(ITy);
+ if (Pred == ICmpInst::ICMP_UGT)
+ return getFalse(ITy);
+ }
+
+ // icmp pred (and X, Y), X
+ if (LBO && match(LBO, m_CombineOr(m_And(m_Value(), m_Specific(RHS)),
+ m_And(m_Specific(RHS), m_Value())))) {
+ if (Pred == ICmpInst::ICMP_UGT)
+ return getFalse(ITy);
+ if (Pred == ICmpInst::ICMP_ULE)
+ return getTrue(ITy);
+ }
+ // icmp pred X, (and X, Y)
+ if (RBO && match(RBO, m_CombineOr(m_And(m_Value(), m_Specific(LHS)),
+ m_And(m_Specific(LHS), m_Value())))) {
+ if (Pred == ICmpInst::ICMP_UGE)
+ return getTrue(ITy);
+ if (Pred == ICmpInst::ICMP_ULT)
+ return getFalse(ITy);
+ }
+
+ // 0 - (zext X) pred C
+ if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
+ if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
+ if (RHSC->getValue().isStrictlyPositive()) {
+ if (Pred == ICmpInst::ICMP_SLT)
+ return ConstantInt::getTrue(RHSC->getContext());
+ if (Pred == ICmpInst::ICMP_SGE)
+ return ConstantInt::getFalse(RHSC->getContext());
+ if (Pred == ICmpInst::ICMP_EQ)
+ return ConstantInt::getFalse(RHSC->getContext());
+ if (Pred == ICmpInst::ICMP_NE)
+ return ConstantInt::getTrue(RHSC->getContext());
+ }
+ if (RHSC->getValue().isNonNegative()) {
+ if (Pred == ICmpInst::ICMP_SLE)
+ return ConstantInt::getTrue(RHSC->getContext());
+ if (Pred == ICmpInst::ICMP_SGT)
+ return ConstantInt::getFalse(RHSC->getContext());
+ }
+ }
+ }
+
+ // icmp pred (urem X, Y), Y
+ if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
+ bool KnownNonNegative, KnownNegative;
+ switch (Pred) {
+ default:
+ break;
+ case ICmpInst::ICMP_SGT:
+ case ICmpInst::ICMP_SGE:
+ ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
+ Q.CxtI, Q.DT);
+ if (!KnownNonNegative)
+ break;
+ // fall-through
+ case ICmpInst::ICMP_EQ:
+ case ICmpInst::ICMP_UGT:
+ case ICmpInst::ICMP_UGE:
+ return getFalse(ITy);
+ case ICmpInst::ICMP_SLT:
+ case ICmpInst::ICMP_SLE:
+ ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
+ Q.CxtI, Q.DT);
+ if (!KnownNonNegative)
+ break;
+ // fall-through
+ case ICmpInst::ICMP_NE:
+ case ICmpInst::ICMP_ULT:
+ case ICmpInst::ICMP_ULE:
+ return getTrue(ITy);
+ }
+ }
+
+ // icmp pred X, (urem Y, X)
+ if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
+ bool KnownNonNegative, KnownNegative;
+ switch (Pred) {
+ default:
+ break;
+ case ICmpInst::ICMP_SGT:
+ case ICmpInst::ICMP_SGE:
+ ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
+ Q.CxtI, Q.DT);
+ if (!KnownNonNegative)
+ break;
+ // fall-through
+ case ICmpInst::ICMP_NE:
+ case ICmpInst::ICMP_UGT:
+ case ICmpInst::ICMP_UGE:
+ return getTrue(ITy);
+ case ICmpInst::ICMP_SLT:
+ case ICmpInst::ICMP_SLE:
+ ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
+ Q.CxtI, Q.DT);
+ if (!KnownNonNegative)
+ break;
+ // fall-through
+ case ICmpInst::ICMP_EQ:
+ case ICmpInst::ICMP_ULT:
+ case ICmpInst::ICMP_ULE:
+ return getFalse(ITy);
+ }
+ }
+
+ // x udiv y <=u x.
+ if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
+ // icmp pred (X /u Y), X
+ if (Pred == ICmpInst::ICMP_UGT)
+ return getFalse(ITy);
+ if (Pred == ICmpInst::ICMP_ULE)
+ return getTrue(ITy);
+ }
+
+ // handle:
+ // CI2 << X == CI
+ // CI2 << X != CI
+ //
+ // where CI2 is a power of 2 and CI isn't
+ if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
+ const APInt *CI2Val, *CIVal = &CI->getValue();
+ if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
+ CI2Val->isPowerOf2()) {
+ if (!CIVal->isPowerOf2()) {
+ // CI2 << X can equal zero in some circumstances,
+ // this simplification is unsafe if CI is zero.
+ //
+ // We know it is safe if:
+ // - The shift is nsw, we can't shift out the one bit.
+ // - The shift is nuw, we can't shift out the one bit.
+ // - CI2 is one
+ // - CI isn't zero
+ if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
+ *CI2Val == 1 || !CI->isZero()) {
+ if (Pred == ICmpInst::ICMP_EQ)
+ return ConstantInt::getFalse(RHS->getContext());
+ if (Pred == ICmpInst::ICMP_NE)
+ return ConstantInt::getTrue(RHS->getContext());
+ }
+ }
+ if (CIVal->isSignBit() && *CI2Val == 1) {
+ if (Pred == ICmpInst::ICMP_UGT)
+ return ConstantInt::getFalse(RHS->getContext());
+ if (Pred == ICmpInst::ICMP_ULE)
+ return ConstantInt::getTrue(RHS->getContext());
+ }
+ }
+ }
+
+ if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
+ LBO->getOperand(1) == RBO->getOperand(1)) {
+ switch (LBO->getOpcode()) {
+ default: break;
+ case Instruction::UDiv:
+ case Instruction::LShr:
+ if (ICmpInst::isSigned(Pred))
+ break;
+ // fall-through
+ case Instruction::SDiv:
+ case Instruction::AShr:
+ if (!LBO->isExact() || !RBO->isExact())
+ break;
+ if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
+ RBO->getOperand(0), Q, MaxRecurse-1))
+ return V;
+ break;
+ case Instruction::Shl: {
+ bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
+ bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
+ if (!NUW && !NSW)
+ break;
+ if (!NSW && ICmpInst::isSigned(Pred))
+ break;
+ if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
+ RBO->getOperand(0), Q, MaxRecurse-1))
+ return V;
+ break;
+ }
+ }
+ }
+
+ // Simplify comparisons involving max/min.
+ Value *A, *B;
+ CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
+ CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
+
+ // Signed variants on "max(a,b)>=a -> true".
+ if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
+ if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
+ EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
+ // We analyze this as smax(A, B) pred A.
+ P = Pred;
+ } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
+ (A == LHS || B == LHS)) {
+ if (A != LHS) std::swap(A, B); // A pred smax(A, B).
+ EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
+ // We analyze this as smax(A, B) swapped-pred A.
+ P = CmpInst::getSwappedPredicate(Pred);
+ } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
+ (A == RHS || B == RHS)) {
+ if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
+ EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
+ // We analyze this as smax(-A, -B) swapped-pred -A.
+ // Note that we do not need to actually form -A or -B thanks to EqP.
+ P = CmpInst::getSwappedPredicate(Pred);
+ } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
+ (A == LHS || B == LHS)) {
+ if (A != LHS) std::swap(A, B); // A pred smin(A, B).
+ EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
+ // We analyze this as smax(-A, -B) pred -A.
+ // Note that we do not need to actually form -A or -B thanks to EqP.
+ P = Pred;
+ }
+ if (P != CmpInst::BAD_ICMP_PREDICATE) {
+ // Cases correspond to "max(A, B) p A".
+ switch (P) {
+ default:
+ break;
+ case CmpInst::ICMP_EQ:
+ case CmpInst::ICMP_SLE:
+ // Equivalent to "A EqP B". This may be the same as the condition tested
+ // in the max/min; if so, we can just return that.
+ if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
+ return V;
+ if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
+ return V;
+ // Otherwise, see if "A EqP B" simplifies.
+ if (MaxRecurse)
+ if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
+ return V;
+ break;
+ case CmpInst::ICMP_NE:
+ case CmpInst::ICMP_SGT: {
+ CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
+ // Equivalent to "A InvEqP B". This may be the same as the condition
+ // tested in the max/min; if so, we can just return that.
+ if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
+ return V;
+ if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
+ return V;
+ // Otherwise, see if "A InvEqP B" simplifies.
+ if (MaxRecurse)
+ if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
+ return V;
+ break;
+ }
+ case CmpInst::ICMP_SGE:
+ // Always true.
+ return getTrue(ITy);
+ case CmpInst::ICMP_SLT:
+ // Always false.
+ return getFalse(ITy);
+ }
+ }
+
+ // Unsigned variants on "max(a,b)>=a -> true".
+ P = CmpInst::BAD_ICMP_PREDICATE;
+ if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
+ if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
+ EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
+ // We analyze this as umax(A, B) pred A.
+ P = Pred;
+ } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
+ (A == LHS || B == LHS)) {
+ if (A != LHS) std::swap(A, B); // A pred umax(A, B).
+ EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
+ // We analyze this as umax(A, B) swapped-pred A.
+ P = CmpInst::getSwappedPredicate(Pred);
+ } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
+ (A == RHS || B == RHS)) {
+ if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
+ EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
+ // We analyze this as umax(-A, -B) swapped-pred -A.
+ // Note that we do not need to actually form -A or -B thanks to EqP.
+ P = CmpInst::getSwappedPredicate(Pred);
+ } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
+ (A == LHS || B == LHS)) {
+ if (A != LHS) std::swap(A, B); // A pred umin(A, B).
+ EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
+ // We analyze this as umax(-A, -B) pred -A.
+ // Note that we do not need to actually form -A or -B thanks to EqP.
+ P = Pred;
+ }
+ if (P != CmpInst::BAD_ICMP_PREDICATE) {
+ // Cases correspond to "max(A, B) p A".
+ switch (P) {
+ default:
+ break;
+ case CmpInst::ICMP_EQ:
+ case CmpInst::ICMP_ULE:
+ // Equivalent to "A EqP B". This may be the same as the condition tested
+ // in the max/min; if so, we can just return that.
+ if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
+ return V;
+ if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
+ return V;
+ // Otherwise, see if "A EqP B" simplifies.
+ if (MaxRecurse)
+ if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
+ return V;
+ break;
+ case CmpInst::ICMP_NE:
+ case CmpInst::ICMP_UGT: {
+ CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
+ // Equivalent to "A InvEqP B". This may be the same as the condition
+ // tested in the max/min; if so, we can just return that.
+ if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
+ return V;
+ if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
+ return V;
+ // Otherwise, see if "A InvEqP B" simplifies.
+ if (MaxRecurse)
+ if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
+ return V;
+ break;
+ }
+ case CmpInst::ICMP_UGE:
+ // Always true.
+ return getTrue(ITy);
+ case CmpInst::ICMP_ULT:
+ // Always false.
+ return getFalse(ITy);
+ }
+ }
+
+ // Variants on "max(x,y) >= min(x,z)".
+ Value *C, *D;
+ if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
+ match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
+ (A == C || A == D || B == C || B == D)) {
+ // max(x, ?) pred min(x, ?).
+ if (Pred == CmpInst::ICMP_SGE)
+ // Always true.
+ return getTrue(ITy);
+ if (Pred == CmpInst::ICMP_SLT)
+ // Always false.
+ return getFalse(ITy);
+ } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
+ match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
+ (A == C || A == D || B == C || B == D)) {
+ // min(x, ?) pred max(x, ?).
+ if (Pred == CmpInst::ICMP_SLE)
+ // Always true.
+ return getTrue(ITy);
+ if (Pred == CmpInst::ICMP_SGT)
+ // Always false.
+ return getFalse(ITy);
+ } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
+ match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
+ (A == C || A == D || B == C || B == D)) {
+ // max(x, ?) pred min(x, ?).
+ if (Pred == CmpInst::ICMP_UGE)
+ // Always true.
+ return getTrue(ITy);
+ if (Pred == CmpInst::ICMP_ULT)
+ // Always false.
+ return getFalse(ITy);
+ } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
+ match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
+ (A == C || A == D || B == C || B == D)) {
+ // min(x, ?) pred max(x, ?).
+ if (Pred == CmpInst::ICMP_ULE)
+ // Always true.
+ return getTrue(ITy);
+ if (Pred == CmpInst::ICMP_UGT)
+ // Always false.
+ return getFalse(ITy);
+ }
+
+ // Simplify comparisons of related pointers using a powerful, recursive
+ // GEP-walk when we have target data available..
+ if (LHS->getType()->isPointerTy())
+ if (Constant *C = computePointerICmp(Q.DL, Q.TLI, Pred, LHS, RHS))
+ return C;
+
+ if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
+ if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
+ if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
+ GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
+ (ICmpInst::isEquality(Pred) ||
+ (GLHS->isInBounds() && GRHS->isInBounds() &&
+ Pred == ICmpInst::getSignedPredicate(Pred)))) {
+ // The bases are equal and the indices are constant. Build a constant
+ // expression GEP with the same indices and a null base pointer to see
+ // what constant folding can make out of it.
+ Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
+ SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
+ Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
+
+ SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
+ Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
+ return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
+ }
+ }
+ }
+
+ // 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, /*Depth=*/0, Q.AC,
+ Q.CxtI, Q.DT);
+ const APInt &RHSVal = CI->getValue();
+ if (((LHSKnownZero & RHSVal) != 0) || ((LHSKnownOne & ~RHSVal) != 0))
+ return Pred == ICmpInst::ICMP_EQ
+ ? ConstantInt::getFalse(CI->getContext())
+ : ConstantInt::getTrue(CI->getContext());
+ }
+ }
+