#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/ValueHandle.h"
+#include "llvm/Support/Allocator.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/DenseMap.h"
#include <iosfwd>
namespace llvm {
class APInt;
class ConstantInt;
class Type;
- class SCEVHandle;
class ScalarEvolution;
class TargetData;
+ class LLVMContext;
- /// SCEV - This class represent an analyzed expression in the program. These
- /// are reference counted opaque objects that the client is not allowed to
- /// do much with directly.
+ /// SCEV - This class represents an analyzed expression in the program. These
+ /// are opaque objects that the client is not allowed to do much with
+ /// directly.
///
- class SCEV {
+ class SCEV : public FoldingSetNode {
const unsigned SCEVType; // The SCEV baseclass this node corresponds to
- mutable unsigned RefCount;
-
- friend class SCEVHandle;
- void addRef() const { ++RefCount; }
- void dropRef() const {
- if (--RefCount == 0)
- delete this;
- }
SCEV(const SCEV &); // DO NOT IMPLEMENT
void operator=(const SCEV &); // DO NOT IMPLEMENT
protected:
virtual ~SCEV();
public:
- explicit SCEV(unsigned SCEVTy) : SCEVType(SCEVTy), RefCount(0) {}
+ explicit SCEV(unsigned SCEVTy) :
+ SCEVType(SCEVTy) {}
+
+ virtual void Profile(FoldingSetNodeID &ID) const = 0;
unsigned getSCEVType() const { return SCEVType; }
///
bool isZero() const;
+ /// isOne - Return true if the expression is a constant one.
+ ///
+ bool isOne() const;
+
+ /// isAllOnesValue - Return true if the expression is a constant
+ /// all-ones value.
+ ///
+ bool isAllOnesValue() const;
+
/// replaceSymbolicValuesWithConcrete - If this SCEV internally references
/// the symbolic value "Sym", construct and return a new SCEV that produces
/// the same value, but which uses the concrete value Conc instead of the
/// symbolic value. If this SCEV does not use the symbolic value, it
/// returns itself.
- virtual SCEVHandle
- replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
- const SCEVHandle &Conc,
+ virtual const SCEV *
+ replaceSymbolicValuesWithConcrete(const SCEV *Sym,
+ const SCEV *Conc,
ScalarEvolution &SE) const = 0;
/// dominates - Return true if elements that makes up this SCEV dominates
/// marker.
struct SCEVCouldNotCompute : public SCEV {
SCEVCouldNotCompute();
- ~SCEVCouldNotCompute();
// None of these methods are valid for this object.
+ virtual void Profile(FoldingSetNodeID &ID) const;
virtual bool isLoopInvariant(const Loop *L) const;
virtual const Type *getType() const;
virtual bool hasComputableLoopEvolution(const Loop *L) const;
virtual void print(raw_ostream &OS) const;
- virtual SCEVHandle
- replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
- const SCEVHandle &Conc,
+ virtual const SCEV *
+ replaceSymbolicValuesWithConcrete(const SCEV *Sym,
+ const SCEV *Conc,
ScalarEvolution &SE) const;
virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const {
static bool classof(const SCEV *S);
};
- /// SCEVCallbackVH - A CallbackVH to arrange for ScalarEvolution to be
- /// notified whenever a Value is deleted.
- class SCEVCallbackVH : public CallbackVH {
- ScalarEvolution *SE;
- virtual void deleted();
- virtual void allUsesReplacedWith(Value *New);
- public:
- SCEVCallbackVH(Value *V, ScalarEvolution *SE = 0);
- };
-
- /// SCEVHandle - This class is used to maintain the SCEV object's refcounts,
- /// freeing the objects when the last reference is dropped.
- class SCEVHandle {
- const SCEV *S;
- SCEVHandle(); // DO NOT IMPLEMENT
- public:
- SCEVHandle(const SCEV *s) : S(s) {
- assert(S && "Cannot create a handle to a null SCEV!");
- S->addRef();
- }
- SCEVHandle(const SCEVHandle &RHS) : S(RHS.S) {
- S->addRef();
- }
- ~SCEVHandle() { S->dropRef(); }
-
- operator const SCEV*() const { return S; }
-
- const SCEV &operator*() const { return *S; }
- const SCEV *operator->() const { return S; }
-
- bool operator==(const SCEV *RHS) const { return S == RHS; }
- bool operator!=(const SCEV *RHS) const { return S != RHS; }
-
- const SCEVHandle &operator=(SCEV *RHS) {
- if (S != RHS) {
- S->dropRef();
- S = RHS;
- S->addRef();
- }
- return *this;
- }
-
- const SCEVHandle &operator=(const SCEVHandle &RHS) {
- if (S != RHS.S) {
- S->dropRef();
- S = RHS.S;
- S->addRef();
- }
- return *this;
- }
- };
-
- template<typename From> struct simplify_type;
- template<> struct simplify_type<const SCEVHandle> {
- typedef const SCEV* SimpleType;
- static SimpleType getSimplifiedValue(const SCEVHandle &Node) {
- return Node;
- }
- };
- template<> struct simplify_type<SCEVHandle>
- : public simplify_type<const SCEVHandle> {};
-
/// ScalarEvolution - This class is the main scalar evolution driver. Because
/// client code (intentionally) can't do much with the SCEV objects directly,
/// they must ask this class for services.
///
class ScalarEvolution : public FunctionPass {
+ /// SCEVCallbackVH - A CallbackVH to arrange for ScalarEvolution to be
+ /// notified whenever a Value is deleted.
+ class SCEVCallbackVH : public CallbackVH {
+ ScalarEvolution *SE;
+ virtual void deleted();
+ virtual void allUsesReplacedWith(Value *New);
+ public:
+ SCEVCallbackVH(Value *V, ScalarEvolution *SE = 0);
+ };
+
friend class SCEVCallbackVH;
+ friend class SCEVExpander;
/// F - The function we are analyzing.
///
///
TargetData *TD;
- /// UnknownValue - This SCEV is used to represent unknown trip counts and
- /// things.
- SCEVHandle UnknownValue;
+ /// CouldNotCompute - This SCEV is used to represent unknown trip
+ /// counts and things.
+ SCEVCouldNotCompute CouldNotCompute;
/// Scalars - This is a cache of the scalars we have analyzed so far.
///
- std::map<SCEVCallbackVH, SCEVHandle> Scalars;
+ std::map<SCEVCallbackVH, const SCEV *> Scalars;
/// BackedgeTakenInfo - Information about the backedge-taken count
/// of a loop. This currently inclues an exact count and a maximum count.
struct BackedgeTakenInfo {
/// Exact - An expression indicating the exact backedge-taken count of
/// the loop if it is known, or a SCEVCouldNotCompute otherwise.
- SCEVHandle Exact;
+ const SCEV *Exact;
/// Exact - An expression indicating the least maximum backedge-taken
/// count of the loop that is known, or a SCEVCouldNotCompute.
- SCEVHandle Max;
-
- /*implicit*/ BackedgeTakenInfo(SCEVHandle exact) :
- Exact(exact), Max(exact) {}
+ const SCEV *Max;
/*implicit*/ BackedgeTakenInfo(const SCEV *exact) :
Exact(exact), Max(exact) {}
- BackedgeTakenInfo(SCEVHandle exact, SCEVHandle max) :
+ BackedgeTakenInfo(const SCEV *exact, const SCEV *max) :
Exact(exact), Max(max) {}
/// hasAnyInfo - Test whether this BackedgeTakenInfo contains any
/// createSCEV - We know that there is no SCEV for the specified value.
/// Analyze the expression.
- SCEVHandle createSCEV(Value *V);
+ const SCEV *createSCEV(Value *V);
/// createNodeForPHI - Provide the special handling we need to analyze PHI
/// SCEVs.
- SCEVHandle createNodeForPHI(PHINode *PN);
+ const SCEV *createNodeForPHI(PHINode *PN);
/// createNodeForGEP - Provide the special handling we need to analyze GEP
/// SCEVs.
- SCEVHandle createNodeForGEP(GetElementPtrInst *GEP);
+ const SCEV *createNodeForGEP(User *GEP);
/// ReplaceSymbolicValueWithConcrete - This looks up the computed SCEV value
/// for the specified instruction and replaces any references to the
/// symbolic value SymName with the specified value. This is used during
/// PHI resolution.
void ReplaceSymbolicValueWithConcrete(Instruction *I,
- const SCEVHandle &SymName,
- const SCEVHandle &NewVal);
+ const SCEV *SymName,
+ const SCEV *NewVal);
+
+ /// getBECount - Subtract the end and start values and divide by the step,
+ /// rounding up, to get the number of times the backedge is executed. Return
+ /// CouldNotCompute if an intermediate computation overflows.
+ const SCEV *getBECount(const SCEV *Start,
+ const SCEV *End,
+ const SCEV *Step);
/// getBackedgeTakenInfo - Return the BackedgeTakenInfo for the given
/// loop, lazily computing new values if the loop hasn't been analyzed
/// loop will iterate.
BackedgeTakenInfo ComputeBackedgeTakenCount(const Loop *L);
+ /// ComputeBackedgeTakenCountFromExit - Compute the number of times the
+ /// backedge of the specified loop will execute if it exits via the
+ /// specified block.
+ BackedgeTakenInfo ComputeBackedgeTakenCountFromExit(const Loop *L,
+ BasicBlock *ExitingBlock);
+
+ /// ComputeBackedgeTakenCountFromExitCond - Compute the number of times the
+ /// backedge of the specified loop will execute if its exit condition
+ /// were a conditional branch of ExitCond, TBB, and FBB.
+ BackedgeTakenInfo
+ ComputeBackedgeTakenCountFromExitCond(const Loop *L,
+ Value *ExitCond,
+ BasicBlock *TBB,
+ BasicBlock *FBB);
+
+ /// ComputeBackedgeTakenCountFromExitCondICmp - Compute the number of
+ /// times the backedge of the specified loop will execute if its exit
+ /// condition were a conditional branch of the ICmpInst ExitCond, TBB,
+ /// and FBB.
+ BackedgeTakenInfo
+ ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L,
+ ICmpInst *ExitCond,
+ BasicBlock *TBB,
+ BasicBlock *FBB);
+
/// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition
/// of 'icmp op load X, cst', try to see if we can compute the trip count.
- SCEVHandle
+ const SCEV *
ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI,
Constant *RHS,
const Loop *L,
/// a constant number of times (the condition evolves only from constants),
/// try to evaluate a few iterations of the loop until we get the exit
/// condition gets a value of ExitWhen (true or false). If we cannot
- /// evaluate the trip count of the loop, return UnknownValue.
- SCEVHandle ComputeBackedgeTakenCountExhaustively(const Loop *L, Value *Cond,
- bool ExitWhen);
+ /// evaluate the trip count of the loop, return CouldNotCompute.
+ const SCEV *ComputeBackedgeTakenCountExhaustively(const Loop *L,
+ Value *Cond,
+ bool ExitWhen);
/// HowFarToZero - Return the number of times a backedge comparing the
/// specified value to zero will execute. If not computable, return
- /// UnknownValue.
- SCEVHandle HowFarToZero(const SCEV *V, const Loop *L);
+ /// CouldNotCompute.
+ const SCEV *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
- /// UnknownValue.
- SCEVHandle HowFarToNonZero(const SCEV *V, const Loop *L);
+ /// CouldNotCompute.
+ const SCEV *HowFarToNonZero(const SCEV *V, const Loop *L);
/// HowManyLessThans - Return the number of times a backedge containing the
/// specified less-than comparison will execute. If not computable, return
- /// UnknownValue. isSigned specifies whether the less-than is signed.
+ /// CouldNotCompute. isSigned specifies whether the less-than is signed.
BackedgeTakenInfo HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
const Loop *L, bool isSigned);
+ /// getLoopPredecessor - If the given loop's header has exactly one unique
+ /// predecessor outside the loop, return it. Otherwise return null.
+ BasicBlock *getLoopPredecessor(const Loop *L);
+
/// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB
/// (which may not be an immediate predecessor) which has exactly one
/// successor from which BB is reachable, or null if no such block is
/// found.
BasicBlock* getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB);
+ /// isNecessaryCond - Test whether the given CondValue value is a condition
+ /// which is at least as strict as the one described by Pred, LHS, and RHS.
+ bool isNecessaryCond(Value *Cond, ICmpInst::Predicate Pred,
+ const SCEV *LHS, const SCEV *RHS,
+ bool Inverse);
+
/// getConstantEvolutionLoopExitValue - If we know that the specified Phi is
/// in the header of its containing loop, we know the loop executes a
/// constant number of times, and the PHI node is just a recurrence
Constant *getConstantEvolutionLoopExitValue(PHINode *PN, const APInt& BEs,
const Loop *L);
- /// forgetLoopPHIs - Delete the memoized SCEVs associated with the
- /// PHI nodes in the given loop. This is used when the trip count of
- /// the loop may have changed.
- void forgetLoopPHIs(const Loop *L);
-
public:
static char ID; // Pass identification, replacement for typeid
ScalarEvolution();
+ LLVMContext *getContext() const { return Context; }
+
/// isSCEVable - Test if values of the given type are analyzable within
/// the SCEV framework. This primarily includes integer types, and it
/// can optionally include pointer types if the ScalarEvolution class
/// getSCEV - Return a SCEV expression handle for the full generality of the
/// specified expression.
- SCEVHandle getSCEV(Value *V);
-
- SCEVHandle getConstant(ConstantInt *V);
- SCEVHandle getConstant(const APInt& Val);
- SCEVHandle getTruncateExpr(const SCEVHandle &Op, const Type *Ty);
- SCEVHandle getZeroExtendExpr(const SCEVHandle &Op, const Type *Ty);
- SCEVHandle getSignExtendExpr(const SCEVHandle &Op, const Type *Ty);
- SCEVHandle getAddExpr(std::vector<SCEVHandle> &Ops);
- SCEVHandle getAddExpr(const SCEVHandle &LHS, const SCEVHandle &RHS) {
- std::vector<SCEVHandle> Ops;
+ const SCEV *getSCEV(Value *V);
+
+ const SCEV *getConstant(ConstantInt *V);
+ const SCEV *getConstant(const APInt& Val);
+ const SCEV *getConstant(const Type *Ty, uint64_t V, bool isSigned = false);
+ const SCEV *getTruncateExpr(const SCEV *Op, const Type *Ty);
+ const SCEV *getZeroExtendExpr(const SCEV *Op, const Type *Ty);
+ const SCEV *getSignExtendExpr(const SCEV *Op, const Type *Ty);
+ const SCEV *getAnyExtendExpr(const SCEV *Op, const Type *Ty);
+ const SCEV *getAddExpr(SmallVectorImpl<const SCEV *> &Ops);
+ const SCEV *getAddExpr(const SCEV *LHS, const SCEV *RHS) {
+ SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
return getAddExpr(Ops);
}
- SCEVHandle getAddExpr(const SCEVHandle &Op0, const SCEVHandle &Op1,
- const SCEVHandle &Op2) {
- std::vector<SCEVHandle> Ops;
+ const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1,
+ const SCEV *Op2) {
+ SmallVector<const SCEV *, 3> Ops;
Ops.push_back(Op0);
Ops.push_back(Op1);
Ops.push_back(Op2);
return getAddExpr(Ops);
}
- SCEVHandle getMulExpr(std::vector<SCEVHandle> &Ops);
- SCEVHandle getMulExpr(const SCEVHandle &LHS, const SCEVHandle &RHS) {
- std::vector<SCEVHandle> Ops;
+ const SCEV *getMulExpr(SmallVectorImpl<const SCEV *> &Ops);
+ const SCEV *getMulExpr(const SCEV *LHS, const SCEV *RHS) {
+ SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
return getMulExpr(Ops);
}
- SCEVHandle getUDivExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
- SCEVHandle getAddRecExpr(const SCEVHandle &Start, const SCEVHandle &Step,
+ const SCEV *getUDivExpr(const SCEV *LHS, const SCEV *RHS);
+ const SCEV *getAddRecExpr(const SCEV *Start, const SCEV *Step,
const Loop *L);
- SCEVHandle getAddRecExpr(std::vector<SCEVHandle> &Operands,
+ const SCEV *getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
const Loop *L);
- SCEVHandle getAddRecExpr(const std::vector<SCEVHandle> &Operands,
+ const SCEV *getAddRecExpr(const SmallVectorImpl<const SCEV *> &Operands,
const Loop *L) {
- std::vector<SCEVHandle> NewOp(Operands);
+ SmallVector<const SCEV *, 4> NewOp(Operands.begin(), Operands.end());
return getAddRecExpr(NewOp, L);
}
- SCEVHandle getSMaxExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
- SCEVHandle getSMaxExpr(std::vector<SCEVHandle> Operands);
- SCEVHandle getUMaxExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
- SCEVHandle getUMaxExpr(std::vector<SCEVHandle> Operands);
- SCEVHandle getUnknown(Value *V);
- SCEVHandle getCouldNotCompute();
+ const SCEV *getSMaxExpr(const SCEV *LHS, const SCEV *RHS);
+ const SCEV *getSMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
+ const SCEV *getUMaxExpr(const SCEV *LHS, const SCEV *RHS);
+ const SCEV *getUMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
+ const SCEV *getSMinExpr(const SCEV *LHS, const SCEV *RHS);
+ const SCEV *getUMinExpr(const SCEV *LHS, const SCEV *RHS);
+ const SCEV *getUnknown(Value *V);
+ const SCEV *getCouldNotCompute();
/// getNegativeSCEV - Return the SCEV object corresponding to -V.
///
- SCEVHandle getNegativeSCEV(const SCEVHandle &V);
+ const SCEV *getNegativeSCEV(const SCEV *V);
/// getNotSCEV - Return the SCEV object corresponding to ~V.
///
- SCEVHandle getNotSCEV(const SCEVHandle &V);
+ const SCEV *getNotSCEV(const SCEV *V);
/// getMinusSCEV - Return LHS-RHS.
///
- SCEVHandle getMinusSCEV(const SCEVHandle &LHS,
- const SCEVHandle &RHS);
+ const SCEV *getMinusSCEV(const SCEV *LHS,
+ const SCEV *RHS);
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
/// extended, it is zero extended.
- SCEVHandle getTruncateOrZeroExtend(const SCEVHandle &V, const Type *Ty);
+ const SCEV *getTruncateOrZeroExtend(const SCEV *V, const Type *Ty);
/// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
/// extended, it is sign extended.
- SCEVHandle getTruncateOrSignExtend(const SCEVHandle &V, const Type *Ty);
-
- /// getIntegerSCEV - Given an integer or FP type, create a constant for the
+ const SCEV *getTruncateOrSignExtend(const SCEV *V, const Type *Ty);
+
+ /// getNoopOrZeroExtend - Return a SCEV corresponding to a conversion of
+ /// the input value to the specified type. If the type must be extended,
+ /// it is zero extended. The conversion must not be narrowing.
+ const SCEV *getNoopOrZeroExtend(const SCEV *V, const Type *Ty);
+
+ /// getNoopOrSignExtend - Return a SCEV corresponding to a conversion of
+ /// the input value to the specified type. If the type must be extended,
+ /// it is sign extended. The conversion must not be narrowing.
+ const SCEV *getNoopOrSignExtend(const SCEV *V, const Type *Ty);
+
+ /// getNoopOrAnyExtend - Return a SCEV corresponding to a conversion of
+ /// the input value to the specified type. If the type must be extended,
+ /// it is extended with unspecified bits. The conversion must not be
+ /// narrowing.
+ const SCEV *getNoopOrAnyExtend(const SCEV *V, const Type *Ty);
+
+ /// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the
+ /// input value to the specified type. The conversion must not be
+ /// widening.
+ const SCEV *getTruncateOrNoop(const SCEV *V, const Type *Ty);
+
+ /// getIntegerSCEV - Given a SCEVable type, create a constant for the
/// specified signed integer value and return a SCEV for the constant.
- SCEVHandle getIntegerSCEV(int Val, const Type *Ty);
+ const SCEV *getIntegerSCEV(int Val, const Type *Ty);
+
+ /// getUMaxFromMismatchedTypes - Promote the operands to the wider of
+ /// the types using zero-extension, and then perform a umax operation
+ /// with them.
+ const SCEV *getUMaxFromMismatchedTypes(const SCEV *LHS,
+ const SCEV *RHS);
+
+ /// getUMinFromMismatchedTypes - Promote the operands to the wider of
+ /// the types using zero-extension, and then perform a umin operation
+ /// with them.
+ const SCEV *getUMinFromMismatchedTypes(const SCEV *LHS,
+ const SCEV *RHS);
/// hasSCEV - Return true if the SCEV for this value has already been
/// computed.
/// setSCEV - Insert the specified SCEV into the map of current SCEVs for
/// the specified value.
- void setSCEV(Value *V, const SCEVHandle &H);
+ void setSCEV(Value *V, const SCEV *H);
/// getSCEVAtScope - Return a SCEV expression handle for the specified value
/// at the specified scope in the program. The L value specifies a loop
/// This method can be used to compute the exit value for a variable defined
/// in a loop by querying what the value will hold in the parent loop.
///
- /// If this value is not computable at this scope, a SCEVCouldNotCompute
- /// object is returned.
- SCEVHandle getSCEVAtScope(const SCEV *S, const Loop *L);
+ /// In the case that a relevant loop exit value cannot be computed, the
+ /// original value V is returned.
+ const SCEV *getSCEVAtScope(const SCEV *S, const Loop *L);
/// getSCEVAtScope - This is a convenience function which does
/// getSCEVAtScope(getSCEV(V), L).
- SCEVHandle getSCEVAtScope(Value *V, const Loop *L);
+ const SCEV *getSCEVAtScope(Value *V, const Loop *L);
/// isLoopGuardedByCond - Test whether entry to the loop is protected by
/// a conditional between LHS and RHS. This is used to help avoid max
/// loop-invariant backedge-taken count (see
/// hasLoopInvariantBackedgeTakenCount).
///
- SCEVHandle getBackedgeTakenCount(const Loop *L);
+ const SCEV *getBackedgeTakenCount(const Loop *L);
/// getMaxBackedgeTakenCount - Similar to getBackedgeTakenCount, except
/// return the least SCEV value that is known never to be less than the
/// actual backedge taken count.
- SCEVHandle getMaxBackedgeTakenCount(const Loop *L);
+ const SCEV *getMaxBackedgeTakenCount(const Loop *L);
/// hasLoopInvariantBackedgeTakenCount - Return true if the specified loop
/// has an analyzable loop-invariant backedge-taken count.
/// is deleted.
void forgetLoopBackedgeTakenCount(const Loop *L);
+ /// GetMinTrailingZeros - Determine the minimum number of zero bits that S
+ /// is guaranteed to end in (at every loop iteration). It is, at the same
+ /// time, the minimum number of times S is divisible by 2. For example,
+ /// given {4,+,8} it returns 2. If S is guaranteed to be 0, it returns the
+ /// bitwidth of S.
+ uint32_t GetMinTrailingZeros(const SCEV *S);
+
+ /// GetMinLeadingZeros - Determine the minimum number of zero bits that S is
+ /// guaranteed to begin with (at every loop iteration).
+ uint32_t GetMinLeadingZeros(const SCEV *S);
+
+ /// GetMinSignBits - Determine the minimum number of sign bits that S is
+ /// guaranteed to begin with.
+ uint32_t GetMinSignBits(const SCEV *S);
+
virtual bool runOnFunction(Function &F);
virtual void releaseMemory();
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
void print(std::ostream *OS, const Module* M = 0) const {
if (OS) print(*OS, M);
}
+
+ private:
+ FoldingSet<SCEV> UniqueSCEVs;
+ BumpPtrAllocator SCEVAllocator;
};
}