//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#define LLVM_ANALYSIS_SCALAREVOLUTION_H
#include "llvm/Pass.h"
+#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Support/DataTypes.h"
-#include "llvm/Support/Streams.h"
-#include <set>
+#include "llvm/Support/ValueHandle.h"
+#include "llvm/ADT/DenseMap.h"
+#include <iosfwd>
namespace llvm {
- class Instruction;
+ class APInt;
+ class ConstantInt;
class Type;
- class ConstantRange;
- class Loop;
- class LoopInfo;
- class SCEVHandle;
-
- /// SCEV - This class represent an analyzed expression in the program. These
- /// are reference counted opaque objects that the client is not allowed to
+ class ScalarEvolution;
+ class TargetData;
+ class SCEVConstant;
+ class SCEVTruncateExpr;
+ class SCEVZeroExtendExpr;
+ class SCEVCommutativeExpr;
+ class SCEVUDivExpr;
+ class SCEVSignExtendExpr;
+ class SCEVAddRecExpr;
+ class SCEVUnknown;
+
+ /// SCEV - This class represents an analyzed expression in the program. These
+ /// are reference-counted opaque objects that the client is not allowed to
/// do much with directly.
///
class SCEV {
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) {}
-
- /// getNegativeSCEV - Return the SCEV object corresponding to -V.
- ///
- static SCEVHandle getNegativeSCEV(const SCEVHandle &V);
-
- /// getMinusSCEV - Return LHS-RHS.
- ///
- static SCEVHandle getMinusSCEV(const SCEVHandle &LHS,
- const SCEVHandle &RHS);
-
+ explicit SCEV(unsigned SCEVTy) :
+ SCEVType(SCEVTy) {}
unsigned getSCEVType() const { return SCEVType; }
- /// getValueRange - Return the tightest constant bounds that this value is
- /// known to have. This method is only valid on integer SCEV objects.
- virtual ConstantRange getValueRange() const;
-
/// isLoopInvariant - Return true if the value of this SCEV is unchanging in
/// the specified loop.
virtual bool isLoopInvariant(const Loop *L) const = 0;
///
virtual const Type *getType() const = 0;
- /// getBitWidth - Get the bit width of the type, if it has one, 0 otherwise.
- ///
- uint32_t getBitWidth() const;
+ /// 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;
/// 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) const = 0;
+ 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
+ /// 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(std::ostream &OS) const = 0;
+ 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;
virtual bool isLoopInvariant(const Loop *L) const;
virtual const Type *getType() const;
virtual bool hasComputableLoopEvolution(const Loop *L) const;
- virtual void print(std::ostream &OS) const;
- void print(std::ostream *OS) const { if (OS) print(*OS); }
- virtual SCEVHandle
- replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
- const SCEVHandle &Conc) const;
+ virtual void print(raw_ostream &OS) const;
+ virtual const SCEV*
+ replaceSymbolicValuesWithConcrete(const SCEV* Sym,
+ const SCEV* Conc,
+ ScalarEvolution &SE) 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);
};
- /// SCEVHandle - This class is used to maintain the SCEV object's refcounts,
- /// freeing the objects when the last reference is dropped.
- class SCEVHandle {
- SCEV *S;
- SCEVHandle(); // DO NOT IMPLEMENT
- public:
- SCEVHandle(const SCEV *s) : S(const_cast<SCEV*>(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(); }
+ /// 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.
+ ///
+ Function *F;
- operator SCEV*() const { return S; }
+ /// LI - The loop information for the function we are currently analyzing.
+ ///
+ LoopInfo *LI;
- SCEV &operator*() const { return *S; }
- SCEV *operator->() const { return S; }
+ /// TD - The target data information for the target we are targetting.
+ ///
+ TargetData *TD;
- bool operator==(SCEV *RHS) const { return S == RHS; }
- bool operator!=(SCEV *RHS) const { return S != RHS; }
+ /// CouldNotCompute - This SCEV is used to represent unknown trip
+ /// counts and things.
+ const SCEV* CouldNotCompute;
- const SCEVHandle &operator=(SCEV *RHS) {
- if (S != RHS) {
- S->dropRef();
- S = RHS;
- S->addRef();
- }
- return *this;
- }
+ /// Scalars - This is a cache of the scalars we have analyzed so far.
+ ///
+ std::map<SCEVCallbackVH, const SCEV*> Scalars;
- const SCEVHandle &operator=(const SCEVHandle &RHS) {
- if (S != RHS.S) {
- S->dropRef();
- S = RHS.S;
- S->addRef();
+ /// 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;
+
+ /// Exact - 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);
}
- return *this;
- }
- };
-
- template<typename From> struct simplify_type;
- template<> struct simplify_type<const SCEVHandle> {
- typedef SCEV* SimpleType;
- static SimpleType getSimplifiedValue(const SCEVHandle &Node) {
- return Node;
- }
- };
- template<> struct simplify_type<SCEVHandle>
- : public simplify_type<const SCEVHandle> {};
+ };
+
+ /// 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(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 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
+ /// 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 trip count.
+ const SCEV*
+ ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI,
+ Constant *RHS,
+ const Loop *L,
+ ICmpInst::Predicate p);
+
+ /// ComputeBackedgeTakenCountExhaustively - If the trip 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 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
+ /// 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);
+
+ /// 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
+ /// involving constants, fold it.
+ 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);
- /// 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 {
- void *Impl; // ScalarEvolution uses the pimpl pattern
public:
static char ID; // Pass identification, replacement for typeid
- ScalarEvolution() : FunctionPass((intptr_t)&ID), Impl(0) {}
+ ScalarEvolution();
+
+ /// 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.
- SCEVHandle getSCEV(Value *V) const;
+ 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* 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);
/// 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(Value *V, const Loop *L) const;
+ /// 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.
+ bool isLoopGuardedByCond(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);
- /// getIterationCount - If the specified loop has a predictable iteration
- /// count, return it, otherwise return a SCEVCouldNotCompute object.
- SCEVHandle getIterationCount(const Loop *L) const;
+ /// 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);
- /// hasLoopInvariantIterationCount - Return true if the specified loop has
- /// an analyzable loop-invariant iteration count.
- bool hasLoopInvariantIterationCount(const Loop *L) const;
+ /// 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);
- /// deleteValueFromRecords - This method should be called by the
- /// client before it removes a Value from the program, to make sure
- /// that no dangling references are left around.
- void deleteValueFromRecords(Value *V) const;
+ /// 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(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:
+ // Uniquing tables.
+ std::map<ConstantInt*, SCEVConstant*> SCEVConstants;
+ std::map<std::pair<const SCEV*, const Type*>,
+ SCEVTruncateExpr*> SCEVTruncates;
+ std::map<std::pair<const SCEV*, const Type*>,
+ SCEVZeroExtendExpr*> SCEVZeroExtends;
+ std::map<std::pair<unsigned, std::vector<const SCEV*> >,
+ SCEVCommutativeExpr*> SCEVCommExprs;
+ std::map<std::pair<const SCEV*, const SCEV*>,
+ SCEVUDivExpr*> SCEVUDivs;
+ std::map<std::pair<const SCEV*, const Type*>,
+ SCEVSignExtendExpr*> SCEVSignExtends;
+ std::map<std::pair<const Loop *, std::vector<const SCEV*> >,
+ SCEVAddRecExpr*> SCEVAddRecExprs;
+ std::map<Value*, SCEVUnknown*> SCEVUnknowns;
};
}
projects / oota-llvm.git / blobdiff