llvm-6502/include/llvm/Analysis/ScalarEvolution.h
Dan Gohman c40f17b087 Generalize ScalarEvolution to be able to analyze GEPs when
TargetData is not present. It still uses TargetData when available.
This generalization also fixed some limitations in the TargetData
case; the attached testcase covers this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79344 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-18 16:46:41 +00:00

617 lines
26 KiB
C++

//===- llvm/Analysis/ScalarEvolution.h - Scalar Evolution -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// The ScalarEvolution class is an LLVM pass which can be used to analyze and
// catagorize scalar expressions in loops. It specializes in recognizing
// general induction variables, representing them with the abstract and opaque
// SCEV class. Given this analysis, trip counts of loops and other important
// properties can be obtained.
//
// This analysis is primarily useful for induction variable substitution and
// strength reduction.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_H
#define LLVM_ANALYSIS_SCALAREVOLUTION_H
#include "llvm/Pass.h"
#include "llvm/Instructions.h"
#include "llvm/Function.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/ValueHandle.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/ConstantRange.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/DenseMap.h"
#include <iosfwd>
#include <map>
namespace llvm {
class APInt;
class Constant;
class ConstantInt;
class DominatorTree;
class Type;
class ScalarEvolution;
class TargetData;
class LLVMContext;
class Loop;
class LoopInfo;
class Operator;
/// 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 : public FastFoldingSetNode {
// The SCEV baseclass this node corresponds to
const unsigned short SCEVType;
protected:
/// SubclassData - This field is initialized to zero and may be used in
/// subclasses to store miscelaneous information.
unsigned short SubclassData;
private:
SCEV(const SCEV &); // DO NOT IMPLEMENT
void operator=(const SCEV &); // DO NOT IMPLEMENT
protected:
virtual ~SCEV();
public:
explicit SCEV(const FoldingSetNodeID &ID, unsigned SCEVTy) :
FastFoldingSetNode(ID), SCEVType(SCEVTy), SubclassData(0) {}
unsigned getSCEVType() const { return SCEVType; }
/// isLoopInvariant - Return true if the value of this SCEV is unchanging in
/// the specified loop.
virtual bool isLoopInvariant(const Loop *L) const = 0;
/// hasComputableLoopEvolution - Return true if this SCEV changes value in a
/// known way in the specified loop. This property being true implies that
/// the value is variant in the loop AND that we can emit an expression to
/// compute the value of the expression at any particular loop iteration.
virtual bool hasComputableLoopEvolution(const Loop *L) const = 0;
/// getType - Return the LLVM type of this SCEV expression.
///
virtual const Type *getType() const = 0;
/// isZero - Return true if the expression is a constant zero.
///
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;
/// hasOperand - Test whether this SCEV has Op as a direct or
/// indirect operand.
virtual bool hasOperand(const SCEV *Op) const = 0;
/// dominates - Return true if elements that makes up this SCEV dominates
/// the specified basic block.
virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const = 0;
/// print - Print out the internal representation of this scalar to the
/// specified stream. This should really only be used for debugging
/// purposes.
virtual void print(raw_ostream &OS) const = 0;
void print(std::ostream &OS) const;
void print(std::ostream *OS) const { if (OS) print(*OS); }
/// dump - This method is used for debugging.
///
void dump() const;
};
inline raw_ostream &operator<<(raw_ostream &OS, const SCEV &S) {
S.print(OS);
return OS;
}
inline std::ostream &operator<<(std::ostream &OS, const SCEV &S) {
S.print(OS);
return OS;
}
/// SCEVCouldNotCompute - An object of this class is returned by queries that
/// could not be answered. For example, if you ask for the number of
/// iterations of a linked-list traversal loop, you will get one of these.
/// None of the standard SCEV operations are valid on this class, it is just a
/// marker.
struct SCEVCouldNotCompute : public SCEV {
SCEVCouldNotCompute();
// None of these methods are valid for this object.
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 bool hasOperand(const SCEV *Op) const;
virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const {
return true;
}
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SCEVCouldNotCompute *S) { return true; }
static bool classof(const SCEV *S);
};
/// 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 struct SCEVExpander;
/// F - The function we are analyzing.
///
Function *F;
/// LI - The loop information for the function we are currently analyzing.
///
LoopInfo *LI;
/// TD - The target data information for the target we are targetting.
///
TargetData *TD;
/// 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, 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.
const SCEV *Exact;
/// Max - An expression indicating the least maximum backedge-taken
/// count of the loop that is known, or a SCEVCouldNotCompute.
const SCEV *Max;
/*implicit*/ BackedgeTakenInfo(const SCEV *exact) :
Exact(exact), Max(exact) {}
BackedgeTakenInfo(const SCEV *exact, const SCEV *max) :
Exact(exact), Max(max) {}
/// hasAnyInfo - Test whether this BackedgeTakenInfo contains any
/// computed information, or whether it's all SCEVCouldNotCompute
/// values.
bool hasAnyInfo() const {
return !isa<SCEVCouldNotCompute>(Exact) ||
!isa<SCEVCouldNotCompute>(Max);
}
};
/// BackedgeTakenCounts - Cache the backedge-taken count of the loops for
/// this function as they are computed.
std::map<const Loop*, BackedgeTakenInfo> BackedgeTakenCounts;
/// ConstantEvolutionLoopExitValue - This map contains entries for all of
/// the PHI instructions that we attempt to compute constant evolutions for.
/// This allows us to avoid potentially expensive recomputation of these
/// properties. An instruction maps to null if we are unable to compute its
/// exit value.
std::map<PHINode*, Constant*> ConstantEvolutionLoopExitValue;
/// ValuesAtScopes - This map contains entries for all the instructions
/// that we attempt to compute getSCEVAtScope information for without
/// using SCEV techniques, which can be expensive.
std::map<Instruction *, std::map<const Loop *, Constant *> > ValuesAtScopes;
/// createSCEV - We know that there is no SCEV for the specified value.
/// Analyze the expression.
const SCEV *createSCEV(Value *V);
/// createNodeForPHI - Provide the special handling we need to analyze PHI
/// SCEVs.
const SCEV *createNodeForPHI(PHINode *PN);
/// createNodeForGEP - Provide the special handling we need to analyze GEP
/// SCEVs.
const SCEV *createNodeForGEP(Operator *GEP);
/// ForgetSymbolicValue - This looks up computed SCEV values for all
/// instructions that depend on the given instruction and removes them from
/// the Scalars map if they reference SymName. This is used during PHI
/// resolution.
void ForgetSymbolicName(Instruction *I, const SCEV *SymName);
/// 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
/// yet.
const BackedgeTakenInfo &getBackedgeTakenInfo(const Loop *L);
/// ComputeBackedgeTakenCount - Compute the number of times the specified
/// 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
/// backedge-taken count.
const SCEV *
ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI,
Constant *RHS,
const Loop *L,
ICmpInst::Predicate p);
/// ComputeBackedgeTakenCountExhaustively - If the loop is known to execute
/// 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 backedge-taken 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
/// 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
/// 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
/// 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);
/// isImpliedCond - Test whether the condition described by Pred, LHS,
/// and RHS is true whenever the given Cond value evaluates to true.
bool isImpliedCond(Value *Cond, ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS,
bool Inverse);
/// isImpliedCondOperands - Test whether the condition described by Pred,
/// LHS, and RHS is true whenever the condition desribed by Pred, FoundLHS,
/// and FoundRHS is true.
bool isImpliedCondOperands(ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS,
const SCEV *FoundLHS, const SCEV *FoundRHS);
/// isImpliedCondOperandsHelper - Test whether the condition described by
/// Pred, LHS, and RHS is true whenever the condition desribed by Pred,
/// FoundLHS, and FoundRHS is true.
bool isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS,
const SCEV *FoundLHS, const SCEV *FoundRHS);
/// 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
/// involving constants, fold it.
Constant *getConstantEvolutionLoopExitValue(PHINode *PN, const APInt& BEs,
const Loop *L);
public:
static char ID; // Pass identification, replacement for typeid
ScalarEvolution();
LLVMContext &getContext() const { return F->getContext(); }
/// 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
/// has access to target-specific information.
bool isSCEVable(const Type *Ty) const;
/// getTypeSizeInBits - Return the size in bits of the specified type,
/// for which isSCEVable must return true.
uint64_t getTypeSizeInBits(const Type *Ty) const;
/// getEffectiveSCEVType - Return a type with the same bitwidth as
/// the given type and which represents how SCEV will treat the given
/// type, for which isSCEVable must return true. For pointer types,
/// this is the pointer-sized integer type.
const Type *getEffectiveSCEVType(const Type *Ty) const;
/// getSCEV - Return a SCEV expression handle for the full generality of the
/// specified expression.
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);
}
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);
}
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);
}
const SCEV *getUDivExpr(const SCEV *LHS, const SCEV *RHS);
const SCEV *getAddRecExpr(const SCEV *Start, const SCEV *Step,
const Loop *L);
const SCEV *getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
const Loop *L);
const SCEV *getAddRecExpr(const SmallVectorImpl<const SCEV *> &Operands,
const Loop *L) {
SmallVector<const SCEV *, 4> NewOp(Operands.begin(), Operands.end());
return getAddRecExpr(NewOp, L);
}
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 *getFieldOffsetExpr(const StructType *STy, unsigned FieldNo);
const SCEV *getAllocSizeExpr(const Type *AllocTy);
const SCEV *getUnknown(Value *V);
const SCEV *getCouldNotCompute();
/// getNegativeSCEV - Return the SCEV object corresponding to -V.
///
const SCEV *getNegativeSCEV(const SCEV *V);
/// getNotSCEV - Return the SCEV object corresponding to ~V.
///
const SCEV *getNotSCEV(const SCEV *V);
/// getMinusSCEV - Return LHS-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.
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.
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.
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);
/// getSCEVAtScope - Return a SCEV expression handle 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.
///
/// 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.
///
/// 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).
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
/// expressions in loop trip counts, and to eliminate casts.
bool isLoopGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS);
/// isLoopBackedgeGuardedByCond - Test whether the backedge of the loop is
/// protected by a conditional between LHS and RHS. This is used to
/// to eliminate casts.
bool isLoopBackedgeGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS);
/// getBackedgeTakenCount - If the specified loop has a predictable
/// backedge-taken count, return it, otherwise return a SCEVCouldNotCompute
/// object. The backedge-taken count is the number of times the loop header
/// will be branched to from within the loop. This is one less than the
/// trip count of the loop, since it doesn't count the first iteration,
/// when the header is branched to from outside the loop.
///
/// Note that it is not valid to call this method on a loop without a
/// loop-invariant backedge-taken count (see
/// hasLoopInvariantBackedgeTakenCount).
///
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.
const SCEV *getMaxBackedgeTakenCount(const Loop *L);
/// hasLoopInvariantBackedgeTakenCount - Return true if the specified loop
/// has an analyzable loop-invariant backedge-taken count.
bool hasLoopInvariantBackedgeTakenCount(const Loop *L);
/// forgetLoopBackedgeTakenCount - This method should be called by the
/// client when it has changed a loop in a way that may effect
/// ScalarEvolution's ability to compute a trip count, or if the loop
/// 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);
/// getUnsignedRange - Determine the unsigned range for a particular SCEV.
///
ConstantRange getUnsignedRange(const SCEV *S);
/// getSignedRange - Determine the signed range for a particular SCEV.
///
ConstantRange getSignedRange(const SCEV *S);
/// isKnownNegative - Test if the given expression is known to be negative.
///
bool isKnownNegative(const SCEV *S);
/// isKnownPositive - Test if the given expression is known to be positive.
///
bool isKnownPositive(const SCEV *S);
/// isKnownNonNegative - Test if the given expression is known to be
/// non-negative.
///
bool isKnownNonNegative(const SCEV *S);
/// isKnownNonPositive - Test if the given expression is known to be
/// non-positive.
///
bool isKnownNonPositive(const SCEV *S);
/// isKnownNonZero - Test if the given expression is known to be
/// non-zero.
///
bool isKnownNonZero(const SCEV *S);
/// isKnownNonZero - Test if the given expression is known to satisfy
/// the condition described by Pred, LHS, and RHS.
///
bool isKnownPredicate(ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS);
virtual bool runOnFunction(Function &F);
virtual void releaseMemory();
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
void print(raw_ostream &OS, const Module* = 0) const;
virtual void print(std::ostream &OS, const Module* = 0) const;
void print(std::ostream *OS, const Module* M = 0) const {
if (OS) print(*OS, M);
}
private:
FoldingSet<SCEV> UniqueSCEVs;
BumpPtrAllocator SCEVAllocator;
};
}
#endif