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-rw-r--r--lib/Analysis/ScalarEvolution.cpp241
1 files changed, 155 insertions, 86 deletions
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 82be9cd..b979f33 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -214,8 +214,8 @@ bool SCEVCastExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeID &ID,
const SCEV *op, const Type *ty)
: SCEVCastExpr(ID, scTruncate, op, ty) {
- assert((Op->getType()->isInteger() || isa<PointerType>(Op->getType())) &&
- (Ty->isInteger() || isa<PointerType>(Ty)) &&
+ assert((Op->getType()->isIntegerTy() || Op->getType()->isPointerTy()) &&
+ (Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot truncate non-integer value!");
}
@@ -226,8 +226,8 @@ void SCEVTruncateExpr::print(raw_ostream &OS) const {
SCEVZeroExtendExpr::SCEVZeroExtendExpr(const FoldingSetNodeID &ID,
const SCEV *op, const Type *ty)
: SCEVCastExpr(ID, scZeroExtend, op, ty) {
- assert((Op->getType()->isInteger() || isa<PointerType>(Op->getType())) &&
- (Ty->isInteger() || isa<PointerType>(Ty)) &&
+ assert((Op->getType()->isIntegerTy() || Op->getType()->isPointerTy()) &&
+ (Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot zero extend non-integer value!");
}
@@ -238,8 +238,8 @@ void SCEVZeroExtendExpr::print(raw_ostream &OS) const {
SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeID &ID,
const SCEV *op, const Type *ty)
: SCEVCastExpr(ID, scSignExtend, op, ty) {
- assert((Op->getType()->isInteger() || isa<PointerType>(Op->getType())) &&
- (Ty->isInteger() || isa<PointerType>(Ty)) &&
+ assert((Op->getType()->isIntegerTy() || Op->getType()->isPointerTy()) &&
+ (Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot sign extend non-integer value!");
}
@@ -312,6 +312,21 @@ bool SCEVAddRecExpr::isLoopInvariant(const Loop *QueryLoop) const {
return true;
}
+bool
+SCEVAddRecExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
+ return DT->dominates(L->getHeader(), BB) &&
+ SCEVNAryExpr::dominates(BB, DT);
+}
+
+bool
+SCEVAddRecExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+ // This uses a "dominates" query instead of "properly dominates" query because
+ // the instruction which produces the addrec's value is a PHI, and a PHI
+ // effectively properly dominates its entire containing block.
+ return DT->dominates(L->getHeader(), BB) &&
+ SCEVNAryExpr::properlyDominates(BB, DT);
+}
+
void SCEVAddRecExpr::print(raw_ostream &OS) const {
OS << "{" << *Operands[0];
for (unsigned i = 1, e = Operands.size(); i != e; ++i)
@@ -379,7 +394,7 @@ bool SCEVUnknown::isAlignOf(const Type *&AllocTy) const {
if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(2)))
if (CI->isOne() &&
STy->getNumElements() == 2 &&
- STy->getElementType(0)->isInteger(1)) {
+ STy->getElementType(0)->isIntegerTy(1)) {
AllocTy = STy->getElementType(1);
return true;
}
@@ -401,7 +416,7 @@ bool SCEVUnknown::isOffsetOf(const Type *&CTy, Constant *&FieldNo) const {
cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
// Ignore vector types here so that ScalarEvolutionExpander doesn't
// emit getelementptrs that index into vectors.
- if (isa<StructType>(Ty) || isa<ArrayType>(Ty)) {
+ if (Ty->isStructTy() || Ty->isArrayTy()) {
CTy = Ty;
FieldNo = CE->getOperand(2);
return true;
@@ -503,9 +518,9 @@ namespace {
// Order pointer values after integer values. This helps SCEVExpander
// form GEPs.
- if (isa<PointerType>(LU->getType()) && !isa<PointerType>(RU->getType()))
+ if (LU->getType()->isPointerTy() && !RU->getType()->isPointerTy())
return false;
- if (isa<PointerType>(RU->getType()) && !isa<PointerType>(LU->getType()))
+ if (RU->getType()->isPointerTy() && !LU->getType()->isPointerTy())
return true;
// Compare getValueID values.
@@ -601,7 +616,7 @@ namespace {
/// When this routine is finished, we know that any duplicates in the vector are
/// consecutive and that complexity is monotonically increasing.
///
-/// Note that we go take special precautions to ensure that we get determinstic
+/// Note that we go take special precautions to ensure that we get deterministic
/// results from this routine. In other words, we don't want the results of
/// this to depend on where the addresses of various SCEV objects happened to
/// land in memory.
@@ -729,7 +744,7 @@ static const SCEV *BinomialCoefficient(const SCEV *It, unsigned K,
// We need at least W + T bits for the multiplication step
unsigned CalculationBits = W + T;
- // Calcuate 2^T, at width T+W.
+ // Calculate 2^T, at width T+W.
APInt DivFactor = APInt(CalculationBits, 1).shl(T);
// Calculate the multiplicative inverse of K! / 2^T;
@@ -906,9 +921,7 @@ const SCEV *ScalarEvolution::getZeroExtendExpr(const SCEV *Op,
if (MaxBECount == RecastedMaxBECount) {
const Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
// Check whether Start+Step*MaxBECount has no unsigned overflow.
- const SCEV *ZMul =
- getMulExpr(CastedMaxBECount,
- getTruncateOrZeroExtend(Step, Start->getType()));
+ const SCEV *ZMul = getMulExpr(CastedMaxBECount, Step);
const SCEV *Add = getAddExpr(Start, ZMul);
const SCEV *OperandExtendedAdd =
getAddExpr(getZeroExtendExpr(Start, WideTy),
@@ -922,9 +935,7 @@ const SCEV *ScalarEvolution::getZeroExtendExpr(const SCEV *Op,
// Similar to above, only this time treat the step value as signed.
// This covers loops that count down.
- const SCEV *SMul =
- getMulExpr(CastedMaxBECount,
- getTruncateOrSignExtend(Step, Start->getType()));
+ const SCEV *SMul = getMulExpr(CastedMaxBECount, Step);
Add = getAddExpr(Start, SMul);
OperandExtendedAdd =
getAddExpr(getZeroExtendExpr(Start, WideTy),
@@ -1045,9 +1056,7 @@ const SCEV *ScalarEvolution::getSignExtendExpr(const SCEV *Op,
if (MaxBECount == RecastedMaxBECount) {
const Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
// Check whether Start+Step*MaxBECount has no signed overflow.
- const SCEV *SMul =
- getMulExpr(CastedMaxBECount,
- getTruncateOrSignExtend(Step, Start->getType()));
+ const SCEV *SMul = getMulExpr(CastedMaxBECount, Step);
const SCEV *Add = getAddExpr(Start, SMul);
const SCEV *OperandExtendedAdd =
getAddExpr(getSignExtendExpr(Start, WideTy),
@@ -1061,9 +1070,7 @@ const SCEV *ScalarEvolution::getSignExtendExpr(const SCEV *Op,
// Similar to above, only this time treat the step value as unsigned.
// This covers loops that count up with an unsigned step.
- const SCEV *UMul =
- getMulExpr(CastedMaxBECount,
- getTruncateOrZeroExtend(Step, Start->getType()));
+ const SCEV *UMul = getMulExpr(CastedMaxBECount, Step);
Add = getAddExpr(Start, UMul);
OperandExtendedAdd =
getAddExpr(getSignExtendExpr(Start, WideTy),
@@ -1403,7 +1410,7 @@ const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
// If we deleted at least one add, we added operands to the end of the list,
// and they are not necessarily sorted. Recurse to resort and resimplify
- // any operands we just aquired.
+ // any operands we just acquired.
if (DeletedAdd)
return getAddExpr(Ops);
}
@@ -1710,7 +1717,7 @@ const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
// If we deleted at least one mul, we added operands to the end of the list,
// and they are not necessarily sorted. Recurse to resort and resimplify
- // any operands we just aquired.
+ // any operands we just acquired.
if (DeletedMul)
return getMulExpr(Ops);
}
@@ -1958,6 +1965,12 @@ ScalarEvolution::getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
return getAddRecExpr(Operands, L, HasNUW, HasNSW); // {X,+,0} --> X
}
+ // It's tempting to want to call getMaxBackedgeTakenCount count here and
+ // use that information to infer NUW and NSW flags. However, computing a
+ // BE count requires calling getAddRecExpr, so we may not yet have a
+ // meaningful BE count at this point (and if we don't, we'd be stuck
+ // with a SCEVCouldNotCompute as the cached BE count).
+
// If HasNSW is true and all the operands are non-negative, infer HasNUW.
if (!HasNUW && HasNSW) {
bool All = true;
@@ -2293,7 +2306,7 @@ const SCEV *ScalarEvolution::getUnknown(Value *V) {
/// has access to target-specific information.
bool ScalarEvolution::isSCEVable(const Type *Ty) const {
// Integers and pointers are always SCEVable.
- return Ty->isInteger() || isa<PointerType>(Ty);
+ return Ty->isIntegerTy() || Ty->isPointerTy();
}
/// getTypeSizeInBits - Return the size in bits of the specified type,
@@ -2306,12 +2319,12 @@ uint64_t ScalarEvolution::getTypeSizeInBits(const Type *Ty) const {
return TD->getTypeSizeInBits(Ty);
// Integer types have fixed sizes.
- if (Ty->isInteger())
+ if (Ty->isIntegerTy())
return Ty->getPrimitiveSizeInBits();
// The only other support type is pointer. Without TargetData, conservatively
// assume pointers are 64-bit.
- assert(isa<PointerType>(Ty) && "isSCEVable permitted a non-SCEVable type!");
+ assert(Ty->isPointerTy() && "isSCEVable permitted a non-SCEVable type!");
return 64;
}
@@ -2322,11 +2335,11 @@ uint64_t ScalarEvolution::getTypeSizeInBits(const Type *Ty) const {
const Type *ScalarEvolution::getEffectiveSCEVType(const Type *Ty) const {
assert(isSCEVable(Ty) && "Type is not SCEVable!");
- if (Ty->isInteger())
+ if (Ty->isIntegerTy())
return Ty;
// The only other support type is pointer.
- assert(isa<PointerType>(Ty) && "Unexpected non-pointer non-integer type!");
+ assert(Ty->isPointerTy() && "Unexpected non-pointer non-integer type!");
if (TD) return TD->getIntPtrType(getContext());
// Without TargetData, conservatively assume pointers are 64-bit.
@@ -2397,8 +2410,8 @@ const SCEV *
ScalarEvolution::getTruncateOrZeroExtend(const SCEV *V,
const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
- (Ty->isInteger() || isa<PointerType>(Ty)) &&
+ assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
+ (Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot truncate or zero extend with non-integer arguments!");
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
return V; // No conversion
@@ -2414,8 +2427,8 @@ const SCEV *
ScalarEvolution::getTruncateOrSignExtend(const SCEV *V,
const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
- (Ty->isInteger() || isa<PointerType>(Ty)) &&
+ assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
+ (Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot truncate or zero extend with non-integer arguments!");
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
return V; // No conversion
@@ -2430,8 +2443,8 @@ ScalarEvolution::getTruncateOrSignExtend(const SCEV *V,
const SCEV *
ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
- (Ty->isInteger() || isa<PointerType>(Ty)) &&
+ assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
+ (Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot noop or zero extend with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
"getNoopOrZeroExtend cannot truncate!");
@@ -2446,8 +2459,8 @@ ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, const Type *Ty) {
const SCEV *
ScalarEvolution::getNoopOrSignExtend(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
- (Ty->isInteger() || isa<PointerType>(Ty)) &&
+ assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
+ (Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot noop or sign extend with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
"getNoopOrSignExtend cannot truncate!");
@@ -2463,8 +2476,8 @@ ScalarEvolution::getNoopOrSignExtend(const SCEV *V, const Type *Ty) {
const SCEV *
ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
- (Ty->isInteger() || isa<PointerType>(Ty)) &&
+ assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
+ (Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot noop or any extend with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
"getNoopOrAnyExtend cannot truncate!");
@@ -2478,8 +2491,8 @@ ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, const Type *Ty) {
const SCEV *
ScalarEvolution::getTruncateOrNoop(const SCEV *V, const Type *Ty) {
const Type *SrcTy = V->getType();
- assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
- (Ty->isInteger() || isa<PointerType>(Ty)) &&
+ assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
+ (Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot truncate or noop with non-integer arguments!");
assert(getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&
"getTruncateOrNoop cannot extend!");
@@ -2536,12 +2549,12 @@ PushDefUseChildren(Instruction *I,
/// the Scalars map if they reference SymName. This is used during PHI
/// resolution.
void
-ScalarEvolution::ForgetSymbolicName(Instruction *I, const SCEV *SymName) {
+ScalarEvolution::ForgetSymbolicName(Instruction *PN, const SCEV *SymName) {
SmallVector<Instruction *, 16> Worklist;
- PushDefUseChildren(I, Worklist);
+ PushDefUseChildren(PN, Worklist);
SmallPtrSet<Instruction *, 8> Visited;
- Visited.insert(I);
+ Visited.insert(PN);
while (!Worklist.empty()) {
Instruction *I = Worklist.pop_back_val();
if (!Visited.insert(I)) continue;
@@ -2551,16 +2564,19 @@ ScalarEvolution::ForgetSymbolicName(Instruction *I, const SCEV *SymName) {
if (It != Scalars.end()) {
// Short-circuit the def-use traversal if the symbolic name
// ceases to appear in expressions.
- if (!It->second->hasOperand(SymName))
+ if (It->second != SymName && !It->second->hasOperand(SymName))
continue;
// SCEVUnknown for a PHI either means that it has an unrecognized
- // structure, or it's a PHI that's in the progress of being computed
- // by createNodeForPHI. In the former case, additional loop trip
- // 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)) {
+ // structure, it's a PHI that's in the progress of being computed
+ // by createNodeForPHI, or it's a single-value PHI. In the first case,
+ // additional loop trip count information isn't going to change anything.
+ // In the second case, createNodeForPHI will perform the necessary
+ // updates on its own when it gets to that point. In the third, we do
+ // want to forget the SCEVUnknown.
+ if (!isa<PHINode>(I) ||
+ !isa<SCEVUnknown>(It->second) ||
+ (I != PN && It->second == SymName)) {
ValuesAtScopes.erase(It->second);
Scalars.erase(It);
}
@@ -2683,9 +2699,21 @@ const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) {
return SymbolicName;
}
- // It's tempting to recognize PHIs with a unique incoming value, however
- // this leads passes like indvars to break LCSSA form. Fortunately, such
- // PHIs are rare, as instcombine zaps them.
+ // If the PHI has a single incoming value, follow that value, unless the
+ // PHI's incoming blocks are in a different loop, in which case doing so
+ // risks breaking LCSSA form. Instcombine would normally zap these, but
+ // it doesn't have DominatorTree information, so it may miss cases.
+ if (Value *V = PN->hasConstantValue(DT)) {
+ bool AllSameLoop = true;
+ Loop *PNLoop = LI->getLoopFor(PN->getParent());
+ for (size_t i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+ if (LI->getLoopFor(PN->getIncomingBlock(i)) != PNLoop) {
+ AllSameLoop = false;
+ break;
+ }
+ if (AllSameLoop)
+ return getSCEV(V);
+ }
// If it's not a loop phi, we can't handle it yet.
return getUnknown(PN);
@@ -2718,7 +2746,7 @@ const SCEV *ScalarEvolution::createNodeForGEP(GEPOperator *GEP) {
} else {
// For an array, add the element offset, explicitly scaled.
const SCEV *LocalOffset = getSCEV(Index);
- // Getelementptr indicies are signed.
+ // Getelementptr indices are signed.
LocalOffset = getTruncateOrSignExtend(LocalOffset, IntPtrTy);
// Lower "inbounds" GEPs to NSW arithmetic.
LocalOffset = getMulExpr(LocalOffset, getSizeOfExpr(*GTI),
@@ -2921,7 +2949,6 @@ ScalarEvolution::getUnsignedRange(const SCEV *S) {
if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
// For a SCEVUnknown, ask ValueTracking.
- unsigned BitWidth = getTypeSizeInBits(U->getType());
APInt Mask = APInt::getAllOnesValue(BitWidth);
APInt Zeros(BitWidth, 0), Ones(BitWidth, 0);
ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones, TD);
@@ -3053,7 +3080,7 @@ ScalarEvolution::getSignedRange(const SCEV *S) {
if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
// For a SCEVUnknown, ask ValueTracking.
- if (!U->getValue()->getType()->isInteger() && !TD)
+ if (!U->getValue()->getType()->isIntegerTy() && !TD)
return ConservativeResult;
unsigned NS = ComputeNumSignBits(U->getValue(), TD);
if (NS == 1)
@@ -3193,7 +3220,7 @@ const SCEV *ScalarEvolution::createSCEV(Value *V) {
const Type *Z0Ty = Z0->getType();
unsigned Z0TySize = getTypeSizeInBits(Z0Ty);
- // If C is a low-bits mask, the zero extend is zerving to
+ // If C is a low-bits mask, the zero extend is serving to
// mask off the high bits. Complement the operand and
// re-apply the zext.
if (APIntOps::isMask(Z0TySize, CI->getValue()))
@@ -3378,7 +3405,7 @@ PushLoopPHIs(const Loop *L, SmallVectorImpl<Instruction *> &Worklist) {
const ScalarEvolution::BackedgeTakenInfo &
ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
// Initially insert a CouldNotCompute for this loop. If the insertion
- // succeeds, procede to actually compute a backedge-taken count and
+ // succeeds, proceed to actually compute a backedge-taken count and
// update the value. The temporary CouldNotCompute value tells SCEV
// code elsewhere that it shouldn't attempt to request a new
// backedge-taken count, which could result in infinite recursion.
@@ -3470,6 +3497,35 @@ void ScalarEvolution::forgetLoop(const Loop *L) {
}
}
+/// forgetValue - This method should be called by the client when it has
+/// changed a value in a way that may effect its value, or which may
+/// disconnect it from a def-use chain linking it to a loop.
+void ScalarEvolution::forgetValue(Value *V) {
+ Instruction *I = dyn_cast<Instruction>(V);
+ if (!I) return;
+
+ // Drop information about expressions based on loop-header PHIs.
+ SmallVector<Instruction *, 16> Worklist;
+ Worklist.push_back(I);
+
+ SmallPtrSet<Instruction *, 8> Visited;
+ while (!Worklist.empty()) {
+ I = Worklist.pop_back_val();
+ if (!Visited.insert(I)) continue;
+
+ std::map<SCEVCallbackVH, const SCEV *>::iterator It =
+ Scalars.find(static_cast<Value *>(I));
+ if (It != Scalars.end()) {
+ ValuesAtScopes.erase(It->second);
+ Scalars.erase(It);
+ if (PHINode *PN = dyn_cast<PHINode>(I))
+ ConstantEvolutionLoopExitValue.erase(PN);
+ }
+
+ PushDefUseChildren(I, Worklist);
+ }
+}
+
/// ComputeBackedgeTakenCount - Compute the number of times the backedge
/// of the specified loop will execute.
ScalarEvolution::BackedgeTakenInfo
@@ -3566,7 +3622,7 @@ ScalarEvolution::ComputeBackedgeTakenCountFromExit(const Loop *L,
return getCouldNotCompute();
}
- // Procede to the next level to examine the exit condition expression.
+ // Proceed to the next level to examine the exit condition expression.
return ComputeBackedgeTakenCountFromExitCond(L, ExitBr->getCondition(),
ExitBr->getSuccessor(0),
ExitBr->getSuccessor(1));
@@ -3655,10 +3711,23 @@ ScalarEvolution::ComputeBackedgeTakenCountFromExitCond(const Loop *L,
}
// With an icmp, it may be feasible to compute an exact backedge-taken count.
- // Procede to the next level to examine the icmp.
+ // Proceed to the next level to examine the icmp.
if (ICmpInst *ExitCondICmp = dyn_cast<ICmpInst>(ExitCond))
return ComputeBackedgeTakenCountFromExitCondICmp(L, ExitCondICmp, TBB, FBB);
+ // Check for a constant condition. These are normally stripped out by
+ // SimplifyCFG, but ScalarEvolution may be used by a pass which wishes to
+ // preserve the CFG and is temporarily leaving constant conditions
+ // in place.
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(ExitCond)) {
+ if (L->contains(FBB) == !CI->getZExtValue())
+ // The backedge is always taken.
+ return getCouldNotCompute();
+ else
+ // The backedge is never taken.
+ return getIntegerSCEV(0, CI->getType());
+ }
+
// If it's not an integer or pointer comparison then compute it the hard way.
return ComputeBackedgeTakenCountExhaustively(L, ExitCond, !L->contains(TBB));
}
@@ -3682,14 +3751,10 @@ ScalarEvolution::ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L,
// Handle common loops like: for (X = "string"; *X; ++X)
if (LoadInst *LI = dyn_cast<LoadInst>(ExitCond->getOperand(0)))
if (Constant *RHS = dyn_cast<Constant>(ExitCond->getOperand(1))) {
- const SCEV *ItCnt =
+ BackedgeTakenInfo ItCnt =
ComputeLoadConstantCompareBackedgeTakenCount(LI, RHS, L, Cond);
- if (!isa<SCEVCouldNotCompute>(ItCnt)) {
- unsigned BitWidth = getTypeSizeInBits(ItCnt->getType());
- return BackedgeTakenInfo(ItCnt,
- isa<SCEVConstant>(ItCnt) ? ItCnt :
- getConstant(APInt::getMaxValue(BitWidth)-1));
- }
+ if (ItCnt.hasAnyInfo())
+ return ItCnt;
}
const SCEV *LHS = getSCEV(ExitCond->getOperand(0));
@@ -3723,14 +3788,14 @@ ScalarEvolution::ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L,
switch (Cond) {
case ICmpInst::ICMP_NE: { // while (X != Y)
// Convert to: while (X-Y != 0)
- const SCEV *TC = HowFarToZero(getMinusSCEV(LHS, RHS), L);
- if (!isa<SCEVCouldNotCompute>(TC)) return TC;
+ BackedgeTakenInfo BTI = HowFarToZero(getMinusSCEV(LHS, RHS), L);
+ if (BTI.hasAnyInfo()) return BTI;
break;
}
case ICmpInst::ICMP_EQ: { // while (X == Y)
// Convert to: while (X-Y == 0)
- const SCEV *TC = HowFarToNonZero(getMinusSCEV(LHS, RHS), L);
- if (!isa<SCEVCouldNotCompute>(TC)) return TC;
+ BackedgeTakenInfo BTI = HowFarToNonZero(getMinusSCEV(LHS, RHS), L);
+ if (BTI.hasAnyInfo()) return BTI;
break;
}
case ICmpInst::ICMP_SLT: {
@@ -3817,7 +3882,7 @@ GetAddressedElementFromGlobal(GlobalVariable *GV,
/// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition of
/// 'icmp op load X, cst', try to see if we can compute the backedge
/// execution count.
-const SCEV *
+ScalarEvolution::BackedgeTakenInfo
ScalarEvolution::ComputeLoadConstantCompareBackedgeTakenCount(
LoadInst *LI,
Constant *RHS,
@@ -3826,6 +3891,7 @@ ScalarEvolution::ComputeLoadConstantCompareBackedgeTakenCount(
if (LI->isVolatile()) return getCouldNotCompute();
// Check to see if the loaded pointer is a getelementptr of a global.
+ // TODO: Use SCEV instead of manually grubbing with GEPs.
GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getOperand(0));
if (!GEP) return getCouldNotCompute();
@@ -4175,14 +4241,15 @@ const SCEV *ScalarEvolution::computeSCEVAtScope(const SCEV *V, const Loop *L) {
}
}
- Constant *C;
+ Constant *C = 0;
if (const CmpInst *CI = dyn_cast<CmpInst>(I))
C = ConstantFoldCompareInstOperands(CI->getPredicate(),
Operands[0], Operands[1], TD);
else
C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
&Operands[0], Operands.size(), TD);
- return getSCEV(C);
+ if (C)
+ return getSCEV(C);
}
}
@@ -4390,7 +4457,8 @@ SolveQuadraticEquation(const SCEVAddRecExpr *AddRec, ScalarEvolution &SE) {
/// HowFarToZero - Return the number of times a backedge comparing the specified
/// value to zero will execute. If not computable, return CouldNotCompute.
-const SCEV *ScalarEvolution::HowFarToZero(const SCEV *V, const Loop *L) {
+ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::HowFarToZero(const SCEV *V, const Loop *L) {
// If the value is a constant
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
// If the value is already zero, the branch will execute zero times.
@@ -4435,7 +4503,7 @@ const SCEV *ScalarEvolution::HowFarToZero(const SCEV *V, const Loop *L) {
-StartC->getValue()->getValue(),
*this);
}
- } else if (AddRec->isQuadratic() && AddRec->getType()->isInteger()) {
+ } else if (AddRec->isQuadratic() && AddRec->getType()->isIntegerTy()) {
// If this is a quadratic (3-term) AddRec {L,+,M,+,N}, find the roots of
// the quadratic equation to solve it.
std::pair<const SCEV *,const SCEV *> Roots = SolveQuadraticEquation(AddRec,
@@ -4470,7 +4538,8 @@ const SCEV *ScalarEvolution::HowFarToZero(const SCEV *V, const Loop *L) {
/// HowFarToNonZero - Return the number of times a backedge checking the
/// specified value for nonzero will execute. If not computable, return
/// CouldNotCompute
-const SCEV *ScalarEvolution::HowFarToNonZero(const SCEV *V, const Loop *L) {
+ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::HowFarToNonZero(const SCEV *V, const Loop *L) {
// Loops that look like: while (X == 0) are very strange indeed. We don't
// handle them yet except for the trivial case. This could be expanded in the
// future as needed.
@@ -4711,7 +4780,7 @@ bool ScalarEvolution::isImpliedCond(Value *CondValue,
ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS,
bool Inverse) {
- // Recursivly handle And and Or conditions.
+ // Recursively handle And and Or conditions.
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(CondValue)) {
if (BO->getOpcode() == Instruction::And) {
if (!Inverse)
@@ -4914,7 +4983,7 @@ bool ScalarEvolution::isImpliedCond(Value *CondValue,
}
/// isImpliedCondOperands - Test whether the condition described by Pred,
-/// LHS, and RHS is true whenever the condition desribed by Pred, FoundLHS,
+/// LHS, and RHS is true whenever the condition described by Pred, FoundLHS,
/// and FoundRHS is true.
bool ScalarEvolution::isImpliedCondOperands(ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS,
@@ -4929,7 +4998,7 @@ bool ScalarEvolution::isImpliedCondOperands(ICmpInst::Predicate Pred,
}
/// isImpliedCondOperandsHelper - Test whether the condition described by
-/// Pred, LHS, and RHS is true whenever the condition desribed by Pred,
+/// Pred, LHS, and RHS is true whenever the condition described by Pred,
/// FoundLHS, and FoundRHS is true.
bool
ScalarEvolution::isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
@@ -5087,7 +5156,7 @@ ScalarEvolution::HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
// If MaxEnd is within a step of the maximum integer value in its type,
// adjust it down to the minimum value which would produce the same effect.
- // This allows the subsequent ceiling divison of (N+(step-1))/step to
+ // This allows the subsequent ceiling division of (N+(step-1))/step to
// compute the correct value.
const SCEV *StepMinusOne = getMinusSCEV(Step,
getIntegerSCEV(1, Step->getType()));
@@ -5304,8 +5373,8 @@ ScalarEvolution::ScalarEvolution()
bool ScalarEvolution::runOnFunction(Function &F) {
this->F = &F;
LI = &getAnalysis<LoopInfo>();
- DT = &getAnalysis<DominatorTree>();
TD = getAnalysisIfAvailable<TargetData>();
+ DT = &getAnalysis<DominatorTree>();
return false;
}
@@ -5364,7 +5433,7 @@ static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE,
}
void ScalarEvolution::print(raw_ostream &OS, const Module *) const {
- // ScalarEvolution's implementaiton of the print method is to print
+ // ScalarEvolution's implementation of the print method is to print
// out SCEV values of all instructions that are interesting. Doing
// this potentially causes it to create new SCEV objects though,
// which technically conflicts with the const qualifier. This isn't
generated by cgit v1.1 at 2024-05-23 02:34:49 +0000