return Op->dominates(BB, DT);
}
+bool SCEVCastExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ return Op->properlyDominates(BB, DT);
+}
+
SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeID &ID,
const SCEV *op, const Type *ty)
: SCEVCastExpr(ID, scTruncate, op, ty) {
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))
+ return false;
+ }
+ return true;
+}
+
bool SCEVUDivExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
return LHS->dominates(BB, DT) && RHS->dominates(BB, DT);
}
+bool SCEVUDivExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ return LHS->properlyDominates(BB, DT) && RHS->properlyDominates(BB, DT);
+}
+
void SCEVUDivExpr::print(raw_ostream &OS) const {
OS << "(" << *LHS << " /u " << *RHS << ")";
}
return true;
}
+bool SCEVUnknown::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ if (Instruction *I = dyn_cast<Instruction>(getValue()))
+ return DT->properlyDominates(I->getParent(), BB);
+ return true;
+}
+
const Type *SCEVUnknown::getType() const {
return V->getType();
}
explicit SCEVComplexityCompare(LoopInfo *li) : LI(li) {}
bool operator()(const SCEV *LHS, const SCEV *RHS) const {
+ // Fast-path: SCEVs are uniqued so we can do a quick equality check.
+ if (LHS == RHS)
+ return false;
+
// Primarily, sort the SCEVs by their getSCEVType().
if (LHS->getSCEVType() != RHS->getSCEVType())
return LHS->getSCEVType() < RHS->getSCEVType();
/// getAddExpr - Get a canonical add expression, or something simpler if
/// possible.
-const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops) {
+const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
+ bool HasNUW, bool HasNSW) {
assert(!Ops.empty() && "Cannot get empty add!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
return Mul;
Ops.erase(Ops.begin()+i, Ops.begin()+i+2);
Ops.push_back(Mul);
- return getAddExpr(Ops);
+ return getAddExpr(Ops, HasNUW, HasNSW);
}
// Check for truncates. If all the operands are truncated from the same
}
if (Ok) {
// Evaluate the expression in the larger type.
- const SCEV *Fold = getAddExpr(LargeOps);
+ const SCEV *Fold = getAddExpr(LargeOps, HasNUW, HasNSW);
// If it folds to something simple, use it. Otherwise, don't.
if (isa<SCEVConstant>(Fold) || isa<SCEVUnknown>(Fold))
return getTruncateExpr(Fold, DstType);
ID.AddPointer(Ops[i]);
void *IP = 0;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- SCEV *S = SCEVAllocator.Allocate<SCEVAddExpr>();
+ SCEVAddExpr *S = SCEVAllocator.Allocate<SCEVAddExpr>();
new (S) SCEVAddExpr(ID, Ops);
UniqueSCEVs.InsertNode(S, IP);
+ if (HasNUW) S->setHasNoUnsignedWrap(true);
+ if (HasNSW) S->setHasNoSignedWrap(true);
return S;
}
/// getMulExpr - Get a canonical multiply expression, or something simpler if
/// possible.
-const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops) {
+const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
+ bool HasNUW, bool HasNSW) {
assert(!Ops.empty() && "Cannot get empty mul!");
#ifndef NDEBUG
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
void *IP = 0;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- SCEV *S = SCEVAllocator.Allocate<SCEVMulExpr>();
+ SCEVMulExpr *S = SCEVAllocator.Allocate<SCEVMulExpr>();
new (S) SCEVMulExpr(ID, Ops);
UniqueSCEVs.InsertNode(S, IP);
+ if (HasNUW) S->setHasNoUnsignedWrap(true);
+ if (HasNSW) S->setHasNoSignedWrap(true);
return S;
}
/// getAddRecExpr - Get an add recurrence expression for the specified loop.
/// Simplify the expression as much as possible.
const SCEV *ScalarEvolution::getAddRecExpr(const SCEV *Start,
- const SCEV *Step, const Loop *L) {
+ const SCEV *Step, const Loop *L,
+ bool HasNUW, bool HasNSW) {
SmallVector<const SCEV *, 4> Operands;
Operands.push_back(Start);
if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step))
}
Operands.push_back(Step);
- return getAddRecExpr(Operands, L);
+ return getAddRecExpr(Operands, L, HasNUW, HasNSW);
}
/// getAddRecExpr - Get an add recurrence expression for the specified loop.
/// Simplify the expression as much as possible.
const SCEV *
ScalarEvolution::getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
- const Loop *L) {
+ const Loop *L,
+ bool HasNUW, bool HasNSW) {
if (Operands.size() == 1) return Operands[0];
#ifndef NDEBUG
for (unsigned i = 1, e = Operands.size(); i != e; ++i)
if (Operands.back()->isZero()) {
Operands.pop_back();
- return getAddRecExpr(Operands, L); // {X,+,0} --> X
+ return getAddRecExpr(Operands, L, HasNUW, HasNSW); // {X,+,0} --> X
}
// Canonicalize nested AddRecs in by nesting them in order of loop depth.
}
if (AllInvariant)
// Ok, both add recurrences are valid after the transformation.
- return getAddRecExpr(NestedOperands, NestedLoop);
+ return getAddRecExpr(NestedOperands, NestedLoop, HasNUW, HasNSW);
}
// Reset Operands to its original state.
Operands[0] = NestedAR;
ID.AddPointer(L);
void *IP = 0;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
- SCEV *S = SCEVAllocator.Allocate<SCEVAddRecExpr>();
+ SCEVAddRecExpr *S = SCEVAllocator.Allocate<SCEVAddRecExpr>();
new (S) SCEVAddRecExpr(ID, Operands, L);
UniqueSCEVs.InsertNode(S, IP);
+ if (HasNUW) S->setHasNoUnsignedWrap(true);
+ if (HasNSW) S->setHasNoSignedWrap(true);
return S;
}
// count information isn't going to change anything. In the later
// case, createNodeForPHI will perform the necessary updates on its
// own when it gets to that point.
- if (!isa<PHINode>(I) || !isa<SCEVUnknown>(It->second))
+ if (!isa<PHINode>(I) || !isa<SCEVUnknown>(It->second)) {
+ ValuesAtScopes.erase(It->second);
Scalars.erase(It);
- ValuesAtScopes.erase(I);
+ }
}
PushDefUseChildren(I, Worklist);
const SCEV *LHS = getSCEV(U->getOperand(0));
const APInt &CIVal = CI->getValue();
if (GetMinTrailingZeros(LHS) >=
- (CIVal.getBitWidth() - CIVal.countLeadingZeros()))
- return getAddExpr(LHS, getSCEV(U->getOperand(1)));
+ (CIVal.getBitWidth() - CIVal.countLeadingZeros())) {
+ // Build a plain add SCEV.
+ const SCEV *S = getAddExpr(LHS, getSCEV(CI));
+ // If the LHS of the add was an addrec and it has no-wrap flags,
+ // transfer the no-wrap flags, since an or won't introduce a wrap.
+ if (const SCEVAddRecExpr *NewAR = dyn_cast<SCEVAddRecExpr>(S)) {
+ const SCEVAddRecExpr *OldAR = cast<SCEVAddRecExpr>(LHS);
+ if (OldAR->hasNoUnsignedWrap())
+ const_cast<SCEVAddRecExpr *>(NewAR)->setHasNoUnsignedWrap(true);
+ if (OldAR->hasNoSignedWrap())
+ const_cast<SCEVAddRecExpr *>(NewAR)->setHasNoSignedWrap(true);
+ }
+ return S;
+ }
}
break;
case Instruction::Xor:
// count information isn't going to change anything. In the later
// case, createNodeForPHI will perform the necessary updates on its
// own when it gets to that point.
- if (!isa<PHINode>(I) || !isa<SCEVUnknown>(It->second))
+ if (!isa<PHINode>(I) || !isa<SCEVUnknown>(It->second)) {
+ ValuesAtScopes.erase(It->second);
Scalars.erase(It);
- ValuesAtScopes.erase(I);
+ }
if (PHINode *PN = dyn_cast<PHINode>(I))
ConstantEvolutionLoopExitValue.erase(PN);
}
std::map<SCEVCallbackVH, const SCEV*>::iterator It =
Scalars.find(static_cast<Value *>(I));
if (It != Scalars.end()) {
+ ValuesAtScopes.erase(It->second);
Scalars.erase(It);
- ValuesAtScopes.erase(I);
if (PHINode *PN = dyn_cast<PHINode>(I))
ConstantEvolutionLoopExitValue.erase(PN);
}
return getCouldNotCompute();
}
-/// getSCEVAtScope - Return a SCEV expression handle for the specified value
+/// getSCEVAtScope - Return a SCEV expression for the specified value
/// at the specified scope in the program. The L value specifies a loop
/// nest to evaluate the expression at, where null is the top-level or a
/// specified loop is immediately inside of the loop.
/// In the case that a relevant loop exit value cannot be computed, the
/// original value V is returned.
const SCEV *ScalarEvolution::getSCEVAtScope(const SCEV *V, const Loop *L) {
- // FIXME: this should be turned into a virtual method on SCEV!
+ // Check to see if we've folded this expression at this loop before.
+ std::map<const Loop *, const SCEV *> &Values = ValuesAtScopes[V];
+ std::pair<std::map<const Loop *, const SCEV *>::iterator, bool> Pair =
+ Values.insert(std::make_pair(L, static_cast<const SCEV *>(0)));
+ if (!Pair.second)
+ return Pair.first->second ? Pair.first->second : V;
+ // Otherwise compute it.
+ const SCEV *C = computeSCEVAtScope(V, L);
+ ValuesAtScopes[V][L] = C;
+ return C;
+}
+
+const SCEV *ScalarEvolution::computeSCEVAtScope(const SCEV *V, const Loop *L) {
if (isa<SCEVConstant>(V)) return V;
// If this instruction is evolved from a constant-evolving PHI, compute the
// the arguments into constants, and if so, try to constant propagate the
// result. This is particularly useful for computing loop exit values.
if (CanConstantFold(I)) {
- // Check to see if we've folded this instruction at this loop before.
- std::map<const Loop *, Constant *> &Values = ValuesAtScopes[I];
- std::pair<std::map<const Loop *, Constant *>::iterator, bool> Pair =
- Values.insert(std::make_pair(L, static_cast<Constant *>(0)));
- if (!Pair.second)
- return Pair.first->second ? &*getSCEV(Pair.first->second) : V;
-
std::vector<Constant*> Operands;
Operands.reserve(I->getNumOperands());
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
&Operands[0], Operands.size(),
getContext());
- Pair.first->second = C;
return getSCEV(C);
}
}
/// CouldNotCompute if an intermediate computation overflows.
const SCEV *ScalarEvolution::getBECount(const SCEV *Start,
const SCEV *End,
- const SCEV *Step) {
+ const SCEV *Step,
+ bool NoWrap) {
const Type *Ty = Start->getType();
const SCEV *NegOne = getIntegerSCEV(-1, Ty);
const SCEV *Diff = getMinusSCEV(End, Start);
// the division will effectively round up.
const SCEV *Add = getAddExpr(Diff, RoundUp);
- // Check Add for unsigned overflow.
- // TODO: More sophisticated things could be done here.
- const Type *WideTy = IntegerType::get(getContext(),
- getTypeSizeInBits(Ty) + 1);
- const SCEV *EDiff = getZeroExtendExpr(Diff, WideTy);
- const SCEV *ERoundUp = getZeroExtendExpr(RoundUp, WideTy);
- const SCEV *OperandExtendedAdd = getAddExpr(EDiff, ERoundUp);
- if (getZeroExtendExpr(Add, WideTy) != OperandExtendedAdd)
- return getCouldNotCompute();
+ if (!NoWrap) {
+ // Check Add for unsigned overflow.
+ // TODO: More sophisticated things could be done here.
+ const Type *WideTy = IntegerType::get(getContext(),
+ getTypeSizeInBits(Ty) + 1);
+ const SCEV *EDiff = getZeroExtendExpr(Diff, WideTy);
+ const SCEV *ERoundUp = getZeroExtendExpr(RoundUp, WideTy);
+ const SCEV *OperandExtendedAdd = getAddExpr(EDiff, ERoundUp);
+ if (getZeroExtendExpr(Add, WideTy) != OperandExtendedAdd)
+ return getCouldNotCompute();
+ }
return getUDivExpr(Add, Step);
}
if (!AddRec || AddRec->getLoop() != L)
return getCouldNotCompute();
+ // Check to see if we have a flag which makes analysis easy.
+ bool NoWrap = isSigned ? AddRec->hasNoSignedWrap() :
+ AddRec->hasNoUnsignedWrap();
+
if (AddRec->isAffine()) {
// FORNOW: We only support unit strides.
unsigned BitWidth = getTypeSizeInBits(AddRec->getType());
if (CStep->isOne()) {
// With unit stride, the iteration never steps past the limit value.
} else if (CStep->getValue()->getValue().isStrictlyPositive()) {
- if (const SCEVConstant *CLimit = dyn_cast<SCEVConstant>(RHS)) {
+ if (NoWrap) {
+ // We know the iteration won't step past the maximum value for its type.
+ ;
+ } else if (const SCEVConstant *CLimit = dyn_cast<SCEVConstant>(RHS)) {
// Test whether a positive iteration iteration can step past the limit
// value and past the maximum value for its type in a single step.
if (isSigned) {
// Finally, we subtract these two values and divide, rounding up, to get
// the number of times the backedge is executed.
- const SCEV *BECount = getBECount(Start, End, Step);
+ const SCEV *BECount = getBECount(Start, End, Step, NoWrap);
// The maximum backedge count is similar, except using the minimum start
// value and the maximum end value.
- const SCEV *MaxBECount = getBECount(MinStart, MaxEnd, Step);
+ const SCEV *MaxBECount = getBECount(MinStart, MaxEnd, Step, NoWrap);
return BackedgeTakenInfo(BECount, MaxBECount);
}
assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!");
if (PHINode *PN = dyn_cast<PHINode>(getValPtr()))
SE->ConstantEvolutionLoopExitValue.erase(PN);
- if (Instruction *I = dyn_cast<Instruction>(getValPtr()))
- SE->ValuesAtScopes.erase(I);
SE->Scalars.erase(getValPtr());
// this now dangles!
}
continue;
if (PHINode *PN = dyn_cast<PHINode>(U))
SE->ConstantEvolutionLoopExitValue.erase(PN);
- if (Instruction *I = dyn_cast<Instruction>(U))
- SE->ValuesAtScopes.erase(I);
SE->Scalars.erase(U);
for (Value::use_iterator UI = U->use_begin(), UE = U->use_end();
UI != UE; ++UI)
if (DeleteOld) {
if (PHINode *PN = dyn_cast<PHINode>(Old))
SE->ConstantEvolutionLoopExitValue.erase(PN);
- if (Instruction *I = dyn_cast<Instruction>(Old))
- SE->ValuesAtScopes.erase(I);
SE->Scalars.erase(Old);
// this now dangles!
}
projects / oota-llvm.git / blobdiff