#include "llvm/Pass.h"
#include "llvm/Instructions.h"
#include "llvm/Function.h"
-#include "llvm/System/DataTypes.h"
+#include "llvm/Operator.h"
+#include "llvm/Support/DataTypes.h"
#include "llvm/Support/ValueHandle.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/ConstantRange.h"
class Loop;
class LoopInfo;
class Operator;
+ class SCEVUnknown;
+ class SCEV;
+ template<> struct FoldingSetTrait<SCEV>;
/// 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 FoldingSetNode {
+ friend struct FoldingSetTrait<SCEV>;
+
/// FastID - A reference to an Interned FoldingSetNodeID for this node.
/// The ScalarEvolution's BumpPtrAllocator holds the data.
FoldingSetNodeIDRef FastID;
- /// AllocationSequenceNumber - This is used as a deterministic tie
- /// breaker when sorting SCEVs.
- unsigned AllocationSequenceNumber;
-
// The SCEV baseclass this node corresponds to
const unsigned short SCEVType;
private:
SCEV(const SCEV &); // DO NOT IMPLEMENT
void operator=(const SCEV &); // DO NOT IMPLEMENT
- protected:
- virtual ~SCEV();
+
public:
- explicit SCEV(const FoldingSetNodeIDRef ID, unsigned num, unsigned SCEVTy) :
- FastID(ID), AllocationSequenceNumber(num),
- SCEVType(SCEVTy), SubclassData(0) {}
+ /// NoWrapFlags are bitfield indices into SubclassData.
+ ///
+ /// Add and Mul expressions may have no-unsigned-wrap <NUW> or
+ /// no-signed-wrap <NSW> properties, which are derived from the IR
+ /// operator. NSW is a misnomer that we use to mean no signed overflow or
+ /// underflow.
+ ///
+ /// AddRec expression may have a no-self-wraparound <NW> property if the
+ /// result can never reach the start value. This property is independent of
+ /// the actual start value and step direction. Self-wraparound is defined
+ /// purely in terms of the recurrence's loop, step size, and
+ /// bitwidth. Formally, a recurrence with no self-wraparound satisfies:
+ /// abs(step) * max-iteration(loop) <= unsigned-max(bitwidth).
+ ///
+ /// Note that NUW and NSW are also valid properties of a recurrence, and
+ /// either implies NW. For convenience, NW will be set for a recurrence
+ /// whenever either NUW or NSW are set.
+ enum NoWrapFlags { FlagAnyWrap = 0, // No guarantee.
+ FlagNW = (1 << 0), // No self-wrap.
+ FlagNUW = (1 << 1), // No unsigned wrap.
+ FlagNSW = (1 << 2), // No signed wrap.
+ NoWrapMask = (1 << 3) -1 };
+
+ explicit SCEV(const FoldingSetNodeIDRef ID, unsigned SCEVTy) :
+ FastID(ID), SCEVType(SCEVTy), SubclassData(0) {}
unsigned getSCEVType() const { return SCEVType; }
- /// getAllocationSequenceNumber - Return an arbitrary value which can be
- /// used to deterministically order a sequence of SCEVs.
- unsigned getAllocationSequenceNumber() const {
- return AllocationSequenceNumber;
- }
-
- /// Profile - FoldingSet support.
- void Profile(FoldingSetNodeID& ID) { ID = FastID; }
-
- /// 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;
+ const Type *getType() const;
/// isZero - Return true if the expression is a constant zero.
///
///
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;
-
- /// properlyDominates - Return true if elements that makes up this SCEV
- /// properly dominate the specified basic block.
- virtual bool properlyDominates(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(raw_ostream &OS) const;
/// dump - This method is used for debugging.
///
void dump() const;
};
+ // Specialize FoldingSetTrait for SCEV to avoid needing to compute
+ // temporary FoldingSetNodeID values.
+ template<> struct FoldingSetTrait<SCEV> : DefaultFoldingSetTrait<SCEV> {
+ static void Profile(const SCEV &X, FoldingSetNodeID& ID) {
+ ID = X.FastID;
+ }
+ static bool Equals(const SCEV &X, const FoldingSetNodeID &ID,
+ FoldingSetNodeID &TempID) {
+ return ID == X.FastID;
+ }
+ static unsigned ComputeHash(const SCEV &X, FoldingSetNodeID &TempID) {
+ return X.FastID.ComputeHash();
+ }
+ };
+
inline raw_ostream &operator<<(raw_ostream &OS, const SCEV &S) {
S.print(OS);
return OS;
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;
- }
-
- virtual bool properlyDominates(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);
/// they must ask this class for services.
///
class ScalarEvolution : public FunctionPass {
+ public:
+ /// LoopDisposition - An enum describing the relationship between a
+ /// SCEV and a loop.
+ enum LoopDisposition {
+ LoopVariant, ///< The SCEV is loop-variant (unknown).
+ LoopInvariant, ///< The SCEV is loop-invariant.
+ LoopComputable ///< The SCEV varies predictably with the loop.
+ };
+
+ /// BlockDisposition - An enum describing the relationship between a
+ /// SCEV and a basic block.
+ enum BlockDisposition {
+ DoesNotDominateBlock, ///< The SCEV does not dominate the block.
+ DominatesBlock, ///< The SCEV dominates the block.
+ ProperlyDominatesBlock ///< The SCEV properly dominates the block.
+ };
+
+ /// Convenient NoWrapFlags manipulation that hides enum casts and is
+ /// visible in the ScalarEvolution name space.
+ static SCEV::NoWrapFlags maskFlags(SCEV::NoWrapFlags Flags, int Mask) {
+ return (SCEV::NoWrapFlags)(Flags & Mask);
+ }
+ static SCEV::NoWrapFlags setFlags(SCEV::NoWrapFlags Flags,
+ SCEV::NoWrapFlags OnFlags) {
+ return (SCEV::NoWrapFlags)(Flags | OnFlags);
+ }
+ static SCEV::NoWrapFlags clearFlags(SCEV::NoWrapFlags Flags,
+ SCEV::NoWrapFlags OffFlags) {
+ return (SCEV::NoWrapFlags)(Flags & ~OffFlags);
+ }
+
+ private:
/// SCEVCallbackVH - A CallbackVH to arrange for ScalarEvolution to be
/// notified whenever a Value is deleted.
class SCEVCallbackVH : public CallbackVH {
friend class SCEVCallbackVH;
friend class SCEVExpander;
+ friend class SCEVUnknown;
/// F - The function we are analyzing.
///
/// counts and things.
SCEVCouldNotCompute CouldNotCompute;
- /// Scalars - This is a cache of the scalars we have analyzed so far.
+ /// ValueExprMapType - The typedef for ValueExprMap.
+ ///
+ typedef DenseMap<SCEVCallbackVH, const SCEV *, DenseMapInfo<Value *> >
+ ValueExprMapType;
+
+ /// ValueExprMap - This is a cache of the values we have analyzed so far.
///
- std::map<SCEVCallbackVH, const SCEV *> Scalars;
+ ValueExprMapType ValueExprMap;
/// BackedgeTakenInfo - Information about the backedge-taken count
/// of a loop. This currently includes an exact count and a maximum count.
std::map<const SCEV *,
std::map<const Loop *, const SCEV *> > ValuesAtScopes;
+ /// LoopDispositions - Memoized computeLoopDisposition results.
+ std::map<const SCEV *,
+ std::map<const Loop *, LoopDisposition> > LoopDispositions;
+
+ /// computeLoopDisposition - Compute a LoopDisposition value.
+ LoopDisposition computeLoopDisposition(const SCEV *S, const Loop *L);
+
+ /// BlockDispositions - Memoized computeBlockDisposition results.
+ std::map<const SCEV *,
+ std::map<const BasicBlock *, BlockDisposition> > BlockDispositions;
+
+ /// computeBlockDisposition - Compute a BlockDisposition value.
+ BlockDisposition computeBlockDisposition(const SCEV *S, const BasicBlock *BB);
+
+ /// UnsignedRanges - Memoized results from getUnsignedRange
+ DenseMap<const SCEV *, ConstantRange> UnsignedRanges;
+
+ /// SignedRanges - Memoized results from getSignedRange
+ DenseMap<const SCEV *, ConstantRange> SignedRanges;
+
+ /// setUnsignedRange - Set the memoized unsigned range for the given SCEV.
+ const ConstantRange &setUnsignedRange(const SCEV *S,
+ const ConstantRange &CR) {
+ std::pair<DenseMap<const SCEV *, ConstantRange>::iterator, bool> Pair =
+ UnsignedRanges.insert(std::make_pair(S, CR));
+ if (!Pair.second)
+ Pair.first->second = CR;
+ return Pair.first->second;
+ }
+
+ /// setUnsignedRange - Set the memoized signed range for the given SCEV.
+ const ConstantRange &setSignedRange(const SCEV *S,
+ const ConstantRange &CR) {
+ std::pair<DenseMap<const SCEV *, ConstantRange>::iterator, bool> Pair =
+ SignedRanges.insert(std::make_pair(S, CR));
+ if (!Pair.second)
+ Pair.first->second = CR;
+ return Pair.first->second;
+ }
+
/// createSCEV - We know that there is no SCEV for the specified value.
/// Analyze the expression.
const SCEV *createSCEV(Value *V);
/// 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
+ /// the ValueExprMap map if they reference SymName. This is used during PHI
/// resolution.
void ForgetSymbolicName(Instruction *I, const SCEV *SymName);
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
std::pair<BasicBlock *, 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,
+ /// isImpliedCond - Test whether the condition described by Pred, LHS, and
+ /// RHS is true whenever the given FoundCondValue value evaluates to true.
+ bool isImpliedCond(ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS,
+ Value *FoundCondValue,
bool Inverse);
/// isImpliedCondOperands - Test whether the condition described by Pred,
bool isKnownPredicateWithRanges(ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS);
+ /// forgetMemoizedResults - Drop memoized information computed for S.
+ void forgetMemoizedResults(const SCEV *S);
+
public:
static char ID; // Pass identification, replacement for typeid
ScalarEvolution();
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,
- bool HasNUW = false, bool HasNSW = false);
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap);
const SCEV *getAddExpr(const SCEV *LHS, const SCEV *RHS,
- bool HasNUW = false, bool HasNSW = false) {
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap) {
SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
- return getAddExpr(Ops, HasNUW, HasNSW);
+ return getAddExpr(Ops, Flags);
}
- const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1,
- const SCEV *Op2,
- bool HasNUW = false, bool HasNSW = false) {
+ const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1, const SCEV *Op2,
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap) {
SmallVector<const SCEV *, 3> Ops;
Ops.push_back(Op0);
Ops.push_back(Op1);
Ops.push_back(Op2);
- return getAddExpr(Ops, HasNUW, HasNSW);
+ return getAddExpr(Ops, Flags);
}
const SCEV *getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
- bool HasNUW = false, bool HasNSW = false);
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap);
const SCEV *getMulExpr(const SCEV *LHS, const SCEV *RHS,
- bool HasNUW = false, bool HasNSW = false) {
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap)
+ {
SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
- return getMulExpr(Ops, HasNUW, HasNSW);
+ return getMulExpr(Ops, Flags);
}
const SCEV *getUDivExpr(const SCEV *LHS, const SCEV *RHS);
const SCEV *getAddRecExpr(const SCEV *Start, const SCEV *Step,
- const Loop *L,
- bool HasNUW = false, bool HasNSW = false);
+ const Loop *L, SCEV::NoWrapFlags Flags);
const SCEV *getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
- const Loop *L,
- bool HasNUW = false, bool HasNSW = false);
+ const Loop *L, SCEV::NoWrapFlags Flags);
const SCEV *getAddRecExpr(const SmallVectorImpl<const SCEV *> &Operands,
- const Loop *L,
- bool HasNUW = false, bool HasNSW = false) {
+ const Loop *L, SCEV::NoWrapFlags Flags) {
SmallVector<const SCEV *, 4> NewOp(Operands.begin(), Operands.end());
- return getAddRecExpr(NewOp, L, HasNUW, HasNSW);
+ return getAddRecExpr(NewOp, L, Flags);
}
const SCEV *getSMaxExpr(const SCEV *LHS, const SCEV *RHS);
const SCEV *getSMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
///
const SCEV *getNotSCEV(const SCEV *V);
- /// getMinusSCEV - Return LHS-RHS.
- ///
- const SCEV *getMinusSCEV(const SCEV *LHS,
- const SCEV *RHS);
+ /// getMinusSCEV - Return LHS-RHS. Minus is represented in SCEV as A+B*-1.
+ const SCEV *getMinusSCEV(const SCEV *LHS, const SCEV *RHS,
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap);
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
const SCEV *getUMinFromMismatchedTypes(const SCEV *LHS,
const SCEV *RHS);
+ /// getPointerBase - Transitively follow the chain of pointer-type operands
+ /// until reaching a SCEV that does not have a single pointer operand. This
+ /// returns a SCEVUnknown pointer for well-formed pointer-type expressions,
+ /// but corner cases do exist.
+ const SCEV *getPointerBase(const SCEV *V);
+
/// getSCEVAtScope - Return a SCEV expression for the specified value
/// at the specified scope in the program. The L value specifies a loop
/// nest to evaluate the expression at, where null is the top-level or a
const SCEV *&LHS,
const SCEV *&RHS);
+ /// getLoopDisposition - Return the "disposition" of the given SCEV with
+ /// respect to the given loop.
+ LoopDisposition getLoopDisposition(const SCEV *S, const Loop *L);
+
+ /// isLoopInvariant - Return true if the value of the given SCEV is
+ /// unchanging in the specified loop.
+ bool isLoopInvariant(const SCEV *S, const Loop *L);
+
+ /// hasComputableLoopEvolution - Return true if the given 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.
+ bool hasComputableLoopEvolution(const SCEV *S, const Loop *L);
+
+ /// getLoopDisposition - Return the "disposition" of the given SCEV with
+ /// respect to the given block.
+ BlockDisposition getBlockDisposition(const SCEV *S, const BasicBlock *BB);
+
+ /// dominates - Return true if elements that makes up the given SCEV
+ /// dominate the specified basic block.
+ bool dominates(const SCEV *S, const BasicBlock *BB);
+
+ /// properlyDominates - Return true if elements that makes up the given SCEV
+ /// properly dominate the specified basic block.
+ bool properlyDominates(const SCEV *S, const BasicBlock *BB);
+
+ /// hasOperand - Test whether the given SCEV has Op as a direct or
+ /// indirect operand.
+ bool hasOperand(const SCEV *S, const SCEV *Op) const;
+
virtual bool runOnFunction(Function &F);
virtual void releaseMemory();
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
private:
FoldingSet<SCEV> UniqueSCEVs;
BumpPtrAllocator SCEVAllocator;
- unsigned CurAllocationSequenceNumber;
+
+ /// FirstUnknown - The head of a linked list of all SCEVUnknown
+ /// values that have been allocated. This is used by releaseMemory
+ /// to locate them all and call their destructors.
+ SCEVUnknown *FirstUnknown;
};
}
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