}
bool SCEVNAryExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- if (!getOperand(i)->dominates(BB, DT))
+ for (op_iterator I = op_begin(), E = op_end(); I != E; ++I)
+ if (!(*I)->dominates(BB, DT))
return false;
- }
return true;
}
bool SCEVNAryExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
- if (!getOperand(i)->properlyDominates(BB, DT))
+ for (op_iterator I = op_begin(), E = op_end(); I != E; ++I)
+ if (!(*I)->properlyDominates(BB, DT))
+ return false;
+ return true;
+}
+
+bool SCEVNAryExpr::isLoopInvariant(const Loop *L) const {
+ for (op_iterator I = op_begin(), E = op_end(); I != E; ++I)
+ if (!(*I)->isLoopInvariant(L))
return false;
- }
return true;
}
+// hasComputableLoopEvolution - N-ary expressions have computable loop
+// evolutions iff they have at least one operand that varies with the loop,
+// but that all varying operands are computable.
+bool SCEVNAryExpr::hasComputableLoopEvolution(const Loop *L) const {
+ bool HasVarying = false;
+ for (op_iterator I = op_begin(), E = op_end(); I != E; ++I) {
+ const SCEV *S = *I;
+ if (!S->isLoopInvariant(L)) {
+ if (S->hasComputableLoopEvolution(L))
+ HasVarying = true;
+ else
+ return false;
+ }
+ }
+ return HasVarying;
+}
+
+bool SCEVNAryExpr::hasOperand(const SCEV *O) const {
+ for (op_iterator I = op_begin(), E = op_end(); I != E; ++I) {
+ const SCEV *S = *I;
+ if (O == S || S->hasOperand(O))
+ return true;
+ }
+ return false;
+}
+
bool SCEVUDivExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
return LHS->dominates(BB, DT) && RHS->dominates(BB, DT);
}
if (QueryLoop->contains(L))
return false;
+ // This recurrence is invariant w.r.t. QueryLoop if L contains QueryLoop.
+ if (L->contains(QueryLoop))
+ return true;
+
// This recurrence is variant w.r.t. QueryLoop if any of its operands
// are variant.
for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
// SCEV Utilities
//===----------------------------------------------------------------------===//
-static bool CompareTypes(const Type *A, const Type *B) {
- if (A->getTypeID() != B->getTypeID())
- return A->getTypeID() < B->getTypeID();
- if (const IntegerType *AI = dyn_cast<IntegerType>(A)) {
- const IntegerType *BI = cast<IntegerType>(B);
- return AI->getBitWidth() < BI->getBitWidth();
- }
- if (const PointerType *AI = dyn_cast<PointerType>(A)) {
- const PointerType *BI = cast<PointerType>(B);
- return CompareTypes(AI->getElementType(), BI->getElementType());
- }
- if (const ArrayType *AI = dyn_cast<ArrayType>(A)) {
- const ArrayType *BI = cast<ArrayType>(B);
- if (AI->getNumElements() != BI->getNumElements())
- return AI->getNumElements() < BI->getNumElements();
- return CompareTypes(AI->getElementType(), BI->getElementType());
- }
- if (const VectorType *AI = dyn_cast<VectorType>(A)) {
- const VectorType *BI = cast<VectorType>(B);
- if (AI->getNumElements() != BI->getNumElements())
- return AI->getNumElements() < BI->getNumElements();
- return CompareTypes(AI->getElementType(), BI->getElementType());
- }
- if (const StructType *AI = dyn_cast<StructType>(A)) {
- const StructType *BI = cast<StructType>(B);
- if (AI->getNumElements() != BI->getNumElements())
- return AI->getNumElements() < BI->getNumElements();
- for (unsigned i = 0, e = AI->getNumElements(); i != e; ++i)
- if (CompareTypes(AI->getElementType(i), BI->getElementType(i)) ||
- CompareTypes(BI->getElementType(i), AI->getElementType(i)))
- return CompareTypes(AI->getElementType(i), BI->getElementType(i));
- }
- return false;
-}
-
namespace {
/// SCEVComplexityCompare - Return true if the complexity of the LHS is less
/// than the complexity of the RHS. This comparator is used to canonicalize
/// expressions.
class SCEVComplexityCompare {
- const LoopInfo *LI;
+ const LoopInfo *const LI;
public:
explicit SCEVComplexityCompare(const LoopInfo *li) : LI(li) {}
// not as complete as it could be.
if (const SCEVUnknown *LU = dyn_cast<SCEVUnknown>(LHS)) {
const SCEVUnknown *RU = cast<SCEVUnknown>(RHS);
+ const Value *LV = LU->getValue(), *RV = RU->getValue();
// Order pointer values after integer values. This helps SCEVExpander
// form GEPs.
- bool LIsPointer = LU->getType()->isPointerTy(),
- RIsPointer = RU->getType()->isPointerTy();
+ bool LIsPointer = LV->getType()->isPointerTy(),
+ RIsPointer = RV->getType()->isPointerTy();
if (LIsPointer != RIsPointer)
return RIsPointer;
// Compare getValueID values.
- unsigned LID = LU->getValue()->getValueID(),
- RID = RU->getValue()->getValueID();
+ unsigned LID = LV->getValueID(),
+ RID = RV->getValueID();
if (LID != RID)
return LID < RID;
// Sort arguments by their position.
- if (const Argument *LA = dyn_cast<Argument>(LU->getValue())) {
- const Argument *RA = cast<Argument>(RU->getValue());
+ if (const Argument *LA = dyn_cast<Argument>(LV)) {
+ const Argument *RA = cast<Argument>(RV);
return LA->getArgNo() < RA->getArgNo();
}
// For instructions, compare their loop depth, and their opcode.
// This is pretty loose.
- if (const Instruction *LV = dyn_cast<Instruction>(LU->getValue())) {
- const Instruction *RV = cast<Instruction>(RU->getValue());
+ if (const Instruction *LInst = dyn_cast<Instruction>(LV)) {
+ const Instruction *RInst = cast<Instruction>(RV);
// Compare loop depths.
- unsigned LDepth = LI->getLoopDepth(LV->getParent()),
- RDepth = LI->getLoopDepth(RV->getParent());
- if (LDepth != RDepth)
- return LDepth < RDepth;
+ const BasicBlock *LParent = LInst->getParent(),
+ *RParent = RInst->getParent();
+ if (LParent != RParent) {
+ unsigned LDepth = LI->getLoopDepth(LParent),
+ RDepth = LI->getLoopDepth(RParent);
+ if (LDepth != RDepth)
+ return LDepth < RDepth;
+ }
// Compare the number of operands.
- unsigned LNumOps = LV->getNumOperands(),
- RNumOps = RV->getNumOperands();
+ unsigned LNumOps = LInst->getNumOperands(),
+ RNumOps = RInst->getNumOperands();
if (LNumOps != RNumOps)
return LNumOps < RNumOps;
}
// Compare constant values.
if (const SCEVConstant *LC = dyn_cast<SCEVConstant>(LHS)) {
const SCEVConstant *RC = cast<SCEVConstant>(RHS);
- const ConstantInt *LCC = LC->getValue();
- const ConstantInt *RCC = RC->getValue();
- unsigned LBitWidth = LCC->getBitWidth(), RBitWidth = RCC->getBitWidth();
+ const APInt &LA = LC->getValue()->getValue();
+ const APInt &RA = RC->getValue()->getValue();
+ unsigned LBitWidth = LA.getBitWidth(), RBitWidth = RA.getBitWidth();
if (LBitWidth != RBitWidth)
return LBitWidth < RBitWidth;
- return LCC->getValue().ult(RCC->getValue());
+ return LA.ult(RA);
}
// Compare addrec loop depths.
if (const SCEVAddRecExpr *LA = dyn_cast<SCEVAddRecExpr>(LHS)) {
const SCEVAddRecExpr *RA = cast<SCEVAddRecExpr>(RHS);
- unsigned LDepth = LA->getLoop()->getLoopDepth(),
- RDepth = RA->getLoop()->getLoopDepth();
- if (LDepth != RDepth)
- return LDepth < RDepth;
+ const Loop *LLoop = LA->getLoop(), *RLoop = RA->getLoop();
+ if (LLoop != RLoop) {
+ unsigned LDepth = LLoop->getLoopDepth(),
+ RDepth = RLoop->getLoopDepth();
+ if (LDepth != RDepth)
+ return LDepth < RDepth;
+ }
}
// Lexicographically compare n-ary expressions.
// If HasNSW is true and all the operands are non-negative, infer HasNUW.
if (!HasNUW && HasNSW) {
bool All = true;
- for (unsigned i = 0, e = Ops.size(); i != e; ++i)
- if (!isKnownNonNegative(Ops[i])) {
+ for (SmallVectorImpl<const SCEV *>::const_iterator I = Ops.begin(),
+ E = Ops.end(); I != E; ++I)
+ if (!isKnownNonNegative(*I)) {
All = false;
break;
}
// so, merge them together into an multiply expression. Since we sorted the
// list, these values are required to be adjacent.
const Type *Ty = Ops[0]->getType();
+ bool FoundMatch = false;
for (unsigned i = 0, e = Ops.size()-1; i != e; ++i)
if (Ops[i] == Ops[i+1]) { // X + Y + Y --> X + Y*2
// Found a match, merge the two values into a multiply, and add any
// remaining values to the result.
const SCEV *Two = getConstant(Ty, 2);
- const SCEV *Mul = getMulExpr(Ops[i], Two);
+ const SCEV *Mul = getMulExpr(Two, Ops[i]);
if (Ops.size() == 2)
return Mul;
- Ops.erase(Ops.begin()+i, Ops.begin()+i+2);
- Ops.push_back(Mul);
- return getAddExpr(Ops, HasNUW, HasNSW);
+ Ops[i] = Mul;
+ Ops.erase(Ops.begin()+i+1);
+ --i; --e;
+ FoundMatch = true;
}
+ if (FoundMatch)
+ return getAddExpr(Ops, HasNUW, HasNSW);
// Check for truncates. If all the operands are truncated from the same
// type, see if factoring out the truncate would permit the result to be
// re-generate the operands list. Group the operands by constant scale,
// to avoid multiplying by the same constant scale multiple times.
std::map<APInt, SmallVector<const SCEV *, 4>, APIntCompare> MulOpLists;
- for (SmallVector<const SCEV *, 8>::iterator I = NewOps.begin(),
+ for (SmallVector<const SCEV *, 8>::const_iterator I = NewOps.begin(),
E = NewOps.end(); I != E; ++I)
MulOpLists[M.find(*I)->second].push_back(*I);
// Re-generate the operands list.
const SCEVMulExpr *Mul = cast<SCEVMulExpr>(Ops[Idx]);
for (unsigned MulOp = 0, e = Mul->getNumOperands(); MulOp != e; ++MulOp) {
const SCEV *MulOpSCEV = Mul->getOperand(MulOp);
+ if (isa<SCEVConstant>(MulOpSCEV))
+ continue;
for (unsigned AddOp = 0, e = Ops.size(); AddOp != e; ++AddOp)
- if (MulOpSCEV == Ops[AddOp] && !isa<SCEVConstant>(Ops[AddOp])) {
+ if (MulOpSCEV == Ops[AddOp]) {
// Fold W + X + (X * Y * Z) --> W + (X * ((Y*Z)+1))
const SCEV *InnerMul = Mul->getOperand(MulOp == 0);
if (Mul->getNumOperands() != 2) {
// If the multiply has more than two operands, we must get the
// Y*Z term.
- SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(), Mul->op_end());
- MulOps.erase(MulOps.begin()+MulOp);
+ SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(),
+ Mul->op_begin()+MulOp);
+ MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end());
InnerMul = getMulExpr(MulOps);
}
const SCEV *One = getConstant(Ty, 1);
- const SCEV *AddOne = getAddExpr(InnerMul, One);
- const SCEV *OuterMul = getMulExpr(AddOne, Ops[AddOp]);
+ const SCEV *AddOne = getAddExpr(One, InnerMul);
+ const SCEV *OuterMul = getMulExpr(AddOne, MulOpSCEV);
if (Ops.size() == 2) return OuterMul;
if (AddOp < Idx) {
Ops.erase(Ops.begin()+AddOp);
}
// Check this multiply against other multiplies being added together.
+ bool AnyFold = false;
for (unsigned OtherMulIdx = Idx+1;
OtherMulIdx < Ops.size() && isa<SCEVMulExpr>(Ops[OtherMulIdx]);
++OtherMulIdx) {
const SCEV *InnerMul1 = Mul->getOperand(MulOp == 0);
if (Mul->getNumOperands() != 2) {
SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(),
- Mul->op_end());
- MulOps.erase(MulOps.begin()+MulOp);
+ Mul->op_begin()+MulOp);
+ MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end());
InnerMul1 = getMulExpr(MulOps);
}
const SCEV *InnerMul2 = OtherMul->getOperand(OMulOp == 0);
if (OtherMul->getNumOperands() != 2) {
SmallVector<const SCEV *, 4> MulOps(OtherMul->op_begin(),
- OtherMul->op_end());
- MulOps.erase(MulOps.begin()+OMulOp);
+ OtherMul->op_begin()+OMulOp);
+ MulOps.append(OtherMul->op_begin()+OMulOp+1, OtherMul->op_end());
InnerMul2 = getMulExpr(MulOps);
}
const SCEV *InnerMulSum = getAddExpr(InnerMul1,InnerMul2);
const SCEV *OuterMul = getMulExpr(MulOpSCEV, InnerMulSum);
if (Ops.size() == 2) return OuterMul;
- Ops.erase(Ops.begin()+Idx);
- Ops.erase(Ops.begin()+OtherMulIdx-1);
- Ops.push_back(OuterMul);
- return getAddExpr(Ops);
+ Ops[Idx] = OuterMul;
+ Ops.erase(Ops.begin()+OtherMulIdx);
+ OtherMulIdx = Idx;
+ AnyFold = true;
}
}
+ if (AnyFold)
+ return getAddExpr(Ops);
}
}
assert(!Ops.empty() && "Cannot get empty mul!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
+ const Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
- assert(getEffectiveSCEVType(Ops[i]->getType()) ==
- getEffectiveSCEVType(Ops[0]->getType()) &&
+ assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
"SCEVMulExpr operand types don't match!");
#endif
// If HasNSW is true and all the operands are non-negative, infer HasNUW.
if (!HasNUW && HasNSW) {
bool All = true;
- for (unsigned i = 0, e = Ops.size(); i != e; ++i)
- if (!isKnownNonNegative(Ops[i])) {
+ for (SmallVectorImpl<const SCEV *>::const_iterator I = Ops.begin(),
+ E = Ops.end(); I != E; ++I)
+ if (!isKnownNonNegative(*I)) {
All = false;
break;
}
if (AddRec->getLoop() == OtherAddRec->getLoop()) {
// F * G --> {A,+,B} * {C,+,D} --> {A*C,+,F*D + G*B + B*D}
const SCEVAddRecExpr *F = AddRec, *G = OtherAddRec;
- const SCEV *NewStart = getMulExpr(F->getStart(),
- G->getStart());
+ const SCEV *NewStart = getMulExpr(F->getStart(), G->getStart());
const SCEV *B = F->getStepRecurrence(*this);
const SCEV *D = G->getStepRecurrence(*this);
const SCEV *NewStep = getAddExpr(getMulExpr(F, D),
- getMulExpr(G, B),
- getMulExpr(B, D));
+ getMulExpr(G, B),
+ getMulExpr(B, D));
const SCEV *NewAddRec = getAddRecExpr(NewStart, NewStep,
- F->getLoop());
+ F->getLoop());
if (Ops.size() == 2) return NewAddRec;
Ops.erase(Ops.begin()+Idx);
bool HasNUW, bool HasNSW) {
if (Operands.size() == 1) return Operands[0];
#ifndef NDEBUG
+ const Type *ETy = getEffectiveSCEVType(Operands[0]->getType());
for (unsigned i = 1, e = Operands.size(); i != e; ++i)
- assert(getEffectiveSCEVType(Operands[i]->getType()) ==
- getEffectiveSCEVType(Operands[0]->getType()) &&
+ assert(getEffectiveSCEVType(Operands[i]->getType()) == ETy &&
"SCEVAddRecExpr operand types don't match!");
#endif
// If HasNSW is true and all the operands are non-negative, infer HasNUW.
if (!HasNUW && HasNSW) {
bool All = true;
- for (unsigned i = 0, e = Operands.size(); i != e; ++i)
- if (!isKnownNonNegative(Operands[i])) {
+ for (SmallVectorImpl<const SCEV *>::const_iterator I = Operands.begin(),
+ E = Operands.end(); I != E; ++I)
+ if (!isKnownNonNegative(*I)) {
All = false;
break;
}
// Canonicalize nested AddRecs in by nesting them in order of loop depth.
if (const SCEVAddRecExpr *NestedAR = dyn_cast<SCEVAddRecExpr>(Operands[0])) {
const Loop *NestedLoop = NestedAR->getLoop();
- if (L->contains(NestedLoop->getHeader()) ?
+ if (L->contains(NestedLoop) ?
(L->getLoopDepth() < NestedLoop->getLoopDepth()) :
- (!NestedLoop->contains(L->getHeader()) &&
+ (!NestedLoop->contains(L) &&
DT->dominates(L->getHeader(), NestedLoop->getHeader()))) {
SmallVector<const SCEV *, 4> NestedOperands(NestedAR->op_begin(),
NestedAR->op_end());
assert(!Ops.empty() && "Cannot get empty smax!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
+ const Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
- assert(getEffectiveSCEVType(Ops[i]->getType()) ==
- getEffectiveSCEVType(Ops[0]->getType()) &&
+ assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
"SCEVSMaxExpr operand types don't match!");
#endif
assert(!Ops.empty() && "Cannot get empty umax!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
+ const Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
- assert(getEffectiveSCEVType(Ops[i]->getType()) ==
- getEffectiveSCEVType(Ops[0]->getType()) &&
+ assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
"SCEVUMaxExpr operand types don't match!");
#endif
const SCEV *ScalarEvolution::getSCEV(Value *V) {
assert(isSCEVable(V->getType()) && "Value is not SCEVable!");
- std::map<SCEVCallbackVH, const SCEV *>::iterator I = Scalars.find(V);
+ std::map<SCEVCallbackVH, const SCEV *>::const_iterator I = Scalars.find(V);
if (I != Scalars.end()) return I->second;
const SCEV *S = createSCEV(V);
+
+ // The process of creating a SCEV for V may have caused other SCEVs
+ // to have been created, so it's necessary to insert the new entry
+ // from scratch, rather than trying to remember the insert position
+ // above.
Scalars.insert(std::make_pair(SCEVCallbackVH(V, this), S));
return S;
}
Operator *U = cast<Operator>(V);
switch (Opcode) {
- case Instruction::Add:
- return getAddExpr(getSCEV(U->getOperand(0)),
- getSCEV(U->getOperand(1)));
- case Instruction::Mul:
- return getMulExpr(getSCEV(U->getOperand(0)),
- getSCEV(U->getOperand(1)));
+ case Instruction::Add: {
+ // The simple thing to do would be to just call getSCEV on both operands
+ // and call getAddExpr with the result. However if we're looking at a
+ // bunch of things all added together, this can be quite inefficient,
+ // because it leads to N-1 getAddExpr calls for N ultimate operands.
+ // Instead, gather up all the operands and make a single getAddExpr call.
+ // LLVM IR canonical form means we need only traverse the left operands.
+ SmallVector<const SCEV *, 4> AddOps;
+ AddOps.push_back(getSCEV(U->getOperand(1)));
+ for (Value *Op = U->getOperand(0);
+ Op->getValueID() == Instruction::Add + Value::InstructionVal;
+ Op = U->getOperand(0)) {
+ U = cast<Operator>(Op);
+ AddOps.push_back(getSCEV(U->getOperand(1)));
+ }
+ AddOps.push_back(getSCEV(U->getOperand(0)));
+ return getAddExpr(AddOps);
+ }
+ case Instruction::Mul: {
+ // See the Add code above.
+ SmallVector<const SCEV *, 4> MulOps;
+ MulOps.push_back(getSCEV(U->getOperand(1)));
+ for (Value *Op = U->getOperand(0);
+ Op->getValueID() == Instruction::Mul + Value::InstructionVal;
+ Op = U->getOperand(0)) {
+ U = cast<Operator>(Op);
+ MulOps.push_back(getSCEV(U->getOperand(1)));
+ }
+ MulOps.push_back(getSCEV(U->getOperand(0)));
+ return getMulExpr(MulOps);
+ }
case Instruction::UDiv:
return getUDivExpr(getSCEV(U->getOperand(0)),
getSCEV(U->getOperand(1)));
const SCEV *LDiff = getMinusSCEV(LA, LS);
const SCEV *RDiff = getMinusSCEV(RA, One);
if (LDiff == RDiff)
- return getAddExpr(getUMaxExpr(LS, One), LDiff);
+ return getAddExpr(getUMaxExpr(One, LS), LDiff);
}
break;
case ICmpInst::ICMP_EQ:
const SCEV *LDiff = getMinusSCEV(LA, One);
const SCEV *RDiff = getMinusSCEV(RA, LS);
if (LDiff == RDiff)
- return getAddExpr(getUMaxExpr(LS, One), LDiff);
+ return getAddExpr(getUMaxExpr(One, LS), LDiff);
}
break;
default:
else
MaxBECount = getUMinFromMismatchedTypes(BTI0.Max, BTI1.Max);
} else {
- // Both conditions must be true for the loop to exit.
+ // Both conditions must be true at the same time for the loop to exit.
+ // For now, be conservative.
assert(L->contains(FBB) && "Loop block has no successor in loop!");
- if (BTI0.Exact != getCouldNotCompute() &&
- BTI1.Exact != getCouldNotCompute())
- BECount = getUMaxFromMismatchedTypes(BTI0.Exact, BTI1.Exact);
- if (BTI0.Max != getCouldNotCompute() &&
- BTI1.Max != getCouldNotCompute())
- MaxBECount = getUMaxFromMismatchedTypes(BTI0.Max, BTI1.Max);
+ if (BTI0.Max == BTI1.Max)
+ MaxBECount = BTI0.Max;
+ if (BTI0.Exact == BTI1.Exact)
+ BECount = BTI0.Exact;
}
return BackedgeTakenInfo(BECount, MaxBECount);
else
MaxBECount = getUMinFromMismatchedTypes(BTI0.Max, BTI1.Max);
} else {
- // Both conditions must be false for the loop to exit.
+ // Both conditions must be false at the same time for the loop to exit.
+ // For now, be conservative.
assert(L->contains(TBB) && "Loop block has no successor in loop!");
- if (BTI0.Exact != getCouldNotCompute() &&
- BTI1.Exact != getCouldNotCompute())
- BECount = getUMaxFromMismatchedTypes(BTI0.Exact, BTI1.Exact);
- if (BTI0.Max != getCouldNotCompute() &&
- BTI1.Max != getCouldNotCompute())
- MaxBECount = getUMaxFromMismatchedTypes(BTI0.Max, BTI1.Max);
+ if (BTI0.Max == BTI1.Max)
+ MaxBECount = BTI0.Max;
+ if (BTI0.Exact == BTI1.Exact)
+ BECount = BTI0.Exact;
}
return BackedgeTakenInfo(BECount, MaxBECount);
ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN,
const APInt &BEs,
const Loop *L) {
- std::map<PHINode*, Constant*>::iterator I =
+ std::map<PHINode*, Constant*>::const_iterator I =
ConstantEvolutionLoopExitValue.find(PN);
if (I != ConstantEvolutionLoopExitValue.end())
return I->second;