X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FAnalysis%2FScalarEvolutionExpressions.h;h=b55ba22a6342f42e38b11af518ce4a049817ff23;hb=2b762697564ca1e12e0e974e93ceeb4c3420505c;hp=1cfc6390ccb4b95712b1512d70638f43c99f3c4f;hpb=b7ef72963b2215ca23c27fa8ea777bada06994d0;p=oota-llvm.git diff --git a/include/llvm/Analysis/ScalarEvolutionExpressions.h b/include/llvm/Analysis/ScalarEvolutionExpressions.h index 1cfc6390ccb..b55ba22a634 100644 --- a/include/llvm/Analysis/ScalarEvolutionExpressions.h +++ b/include/llvm/Analysis/ScalarEvolutionExpressions.h @@ -11,23 +11,25 @@ // //===----------------------------------------------------------------------===// -#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H -#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H +#ifndef LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H +#define LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/iterator_range.h" #include "llvm/Analysis/ScalarEvolution.h" +#include "llvm/Support/ErrorHandling.h" namespace llvm { class ConstantInt; class ConstantRange; - class APInt; class DominatorTree; enum SCEVTypes { // These should be ordered in terms of increasing complexity to make the // folders simpler. scConstant, scTruncate, scZeroExtend, scSignExtend, scAddExpr, scMulExpr, - scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr, scUnknown, - scCouldNotCompute + scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr, + scUnknown, scCouldNotCompute }; //===--------------------------------------------------------------------===// @@ -37,38 +39,39 @@ namespace llvm { friend class ScalarEvolution; ConstantInt *V; - explicit SCEVConstant(ConstantInt *v) : SCEV(scConstant), V(v) {} - - virtual ~SCEVConstant(); + SCEVConstant(const FoldingSetNodeIDRef ID, ConstantInt *v) : + SCEV(ID, scConstant), V(v) {} public: ConstantInt *getValue() const { return V; } - virtual bool isLoopInvariant(const Loop *L) const { - return true; - } + Type *getType() const { return V->getType(); } - virtual bool hasComputableLoopEvolution(const Loop *L) const { - return false; // Not loop variant + /// Methods for support type inquiry through isa, cast, and dyn_cast: + static inline bool classof(const SCEV *S) { + return S->getSCEVType() == scConstant; } + }; - virtual const Type *getType() const; + //===--------------------------------------------------------------------===// + /// SCEVCastExpr - This is the base class for unary cast operator classes. + /// + class SCEVCastExpr : public SCEV { + protected: + const SCEV *Op; + Type *Ty; - SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym, - const SCEVHandle &Conc, - ScalarEvolution &SE) const { - return this; - } + SCEVCastExpr(const FoldingSetNodeIDRef ID, + unsigned SCEVTy, const SCEV *op, Type *ty); - bool dominates(BasicBlock *BB, DominatorTree *DT) const { - return true; - } - - virtual void print(raw_ostream &OS) const; + public: + const SCEV *getOperand() const { return Op; } + Type *getType() const { return Ty; } /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVConstant *S) { return true; } static inline bool classof(const SCEV *S) { - return S->getSCEVType() == scConstant; + return S->getSCEVType() == scTruncate || + S->getSCEVType() == scZeroExtend || + S->getSCEVType() == scSignExtend; } }; @@ -76,40 +79,14 @@ namespace llvm { /// SCEVTruncateExpr - This class represents a truncation of an integer value /// to a smaller integer value. /// - class SCEVTruncateExpr : public SCEV { + class SCEVTruncateExpr : public SCEVCastExpr { friend class ScalarEvolution; - SCEVHandle Op; - const Type *Ty; - SCEVTruncateExpr(const SCEVHandle &op, const Type *ty); - virtual ~SCEVTruncateExpr(); - public: - const SCEVHandle &getOperand() const { return Op; } - virtual const Type *getType() const { return Ty; } - - virtual bool isLoopInvariant(const Loop *L) const { - return Op->isLoopInvariant(L); - } - - virtual bool hasComputableLoopEvolution(const Loop *L) const { - return Op->hasComputableLoopEvolution(L); - } - - SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym, - const SCEVHandle &Conc, - ScalarEvolution &SE) const { - SCEVHandle H = Op->replaceSymbolicValuesWithConcrete(Sym, Conc, SE); - if (H == Op) - return this; - return SE.getTruncateExpr(H, Ty); - } - - virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const; - - virtual void print(raw_ostream &OS) const; + SCEVTruncateExpr(const FoldingSetNodeIDRef ID, + const SCEV *op, Type *ty); + public: /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVTruncateExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scTruncate; } @@ -119,40 +96,14 @@ namespace llvm { /// SCEVZeroExtendExpr - This class represents a zero extension of a small /// integer value to a larger integer value. /// - class SCEVZeroExtendExpr : public SCEV { + class SCEVZeroExtendExpr : public SCEVCastExpr { friend class ScalarEvolution; - SCEVHandle Op; - const Type *Ty; - SCEVZeroExtendExpr(const SCEVHandle &op, const Type *ty); - virtual ~SCEVZeroExtendExpr(); - public: - const SCEVHandle &getOperand() const { return Op; } - virtual const Type *getType() const { return Ty; } - - virtual bool isLoopInvariant(const Loop *L) const { - return Op->isLoopInvariant(L); - } - - virtual bool hasComputableLoopEvolution(const Loop *L) const { - return Op->hasComputableLoopEvolution(L); - } - - SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym, - const SCEVHandle &Conc, - ScalarEvolution &SE) const { - SCEVHandle H = Op->replaceSymbolicValuesWithConcrete(Sym, Conc, SE); - if (H == Op) - return this; - return SE.getZeroExtendExpr(H, Ty); - } - - bool dominates(BasicBlock *BB, DominatorTree *DT) const; - - virtual void print(raw_ostream &OS) const; + SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID, + const SCEV *op, Type *ty); + public: /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVZeroExtendExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scZeroExtend; } @@ -162,40 +113,14 @@ namespace llvm { /// SCEVSignExtendExpr - This class represents a sign extension of a small /// integer value to a larger integer value. /// - class SCEVSignExtendExpr : public SCEV { + class SCEVSignExtendExpr : public SCEVCastExpr { friend class ScalarEvolution; - SCEVHandle Op; - const Type *Ty; - SCEVSignExtendExpr(const SCEVHandle &op, const Type *ty); - virtual ~SCEVSignExtendExpr(); - public: - const SCEVHandle &getOperand() const { return Op; } - virtual const Type *getType() const { return Ty; } - - virtual bool isLoopInvariant(const Loop *L) const { - return Op->isLoopInvariant(L); - } - - virtual bool hasComputableLoopEvolution(const Loop *L) const { - return Op->hasComputableLoopEvolution(L); - } - - SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym, - const SCEVHandle &Conc, - ScalarEvolution &SE) const { - SCEVHandle H = Op->replaceSymbolicValuesWithConcrete(Sym, Conc, SE); - if (H == Op) - return this; - return SE.getSignExtendExpr(H, Ty); - } - - bool dominates(BasicBlock *BB, DominatorTree *DT) const; - - virtual void print(raw_ostream &OS) const; + SCEVSignExtendExpr(const FoldingSetNodeIDRef ID, + const SCEV *op, Type *ty); + public: /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVSignExtendExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scSignExtend; } @@ -203,75 +128,76 @@ namespace llvm { //===--------------------------------------------------------------------===// - /// SCEVCommutativeExpr - This node is the base class for n'ary commutative - /// operators. + /// SCEVNAryExpr - This node is a base class providing common + /// functionality for n'ary operators. /// - class SCEVCommutativeExpr : public SCEV { - friend class ScalarEvolution; - - std::vector Operands; - + class SCEVNAryExpr : public SCEV { protected: - SCEVCommutativeExpr(enum SCEVTypes T, const std::vector &ops) - : SCEV(T) { - Operands.reserve(ops.size()); - Operands.insert(Operands.end(), ops.begin(), ops.end()); - } - ~SCEVCommutativeExpr(); + // Since SCEVs are immutable, ScalarEvolution allocates operand + // arrays with its SCEVAllocator, so this class just needs a simple + // pointer rather than a more elaborate vector-like data structure. + // This also avoids the need for a non-trivial destructor. + const SCEV *const *Operands; + size_t NumOperands; + + SCEVNAryExpr(const FoldingSetNodeIDRef ID, + enum SCEVTypes T, const SCEV *const *O, size_t N) + : SCEV(ID, T), Operands(O), NumOperands(N) {} public: - unsigned getNumOperands() const { return (unsigned)Operands.size(); } - const SCEVHandle &getOperand(unsigned i) const { - assert(i < Operands.size() && "Operand index out of range!"); + size_t getNumOperands() const { return NumOperands; } + const SCEV *getOperand(unsigned i) const { + assert(i < NumOperands && "Operand index out of range!"); return Operands[i]; } - const std::vector &getOperands() const { return Operands; } - typedef std::vector::const_iterator op_iterator; - op_iterator op_begin() const { return Operands.begin(); } - op_iterator op_end() const { return Operands.end(); } + typedef const SCEV *const *op_iterator; + typedef iterator_range op_range; + op_iterator op_begin() const { return Operands; } + op_iterator op_end() const { return Operands + NumOperands; } + op_range operands() const { + return make_range(op_begin(), op_end()); + } + Type *getType() const { return getOperand(0)->getType(); } - virtual bool isLoopInvariant(const Loop *L) const { - for (unsigned i = 0, e = getNumOperands(); i != e; ++i) - if (!getOperand(i)->isLoopInvariant(L)) return false; - return true; + NoWrapFlags getNoWrapFlags(NoWrapFlags Mask = NoWrapMask) const { + return (NoWrapFlags)(SubclassData & Mask); } - // hasComputableLoopEvolution - Commutative expressions have computable loop - // evolutions iff they have at least one operand that varies with the loop, - // but that all varying operands are computable. - virtual bool hasComputableLoopEvolution(const Loop *L) const { - bool HasVarying = false; - for (unsigned i = 0, e = getNumOperands(); i != e; ++i) - if (!getOperand(i)->isLoopInvariant(L)) { - if (getOperand(i)->hasComputableLoopEvolution(L)) - HasVarying = true; - else - return false; - } - return HasVarying; + /// Methods for support type inquiry through isa, cast, and dyn_cast: + static inline bool classof(const SCEV *S) { + return S->getSCEVType() == scAddExpr || + S->getSCEVType() == scMulExpr || + S->getSCEVType() == scSMaxExpr || + S->getSCEVType() == scUMaxExpr || + S->getSCEVType() == scAddRecExpr; } + }; - SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym, - const SCEVHandle &Conc, - ScalarEvolution &SE) const; - - bool dominates(BasicBlock *BB, DominatorTree *DT) const; - - virtual const char *getOperationStr() const = 0; - - virtual const Type *getType() const { return getOperand(0)->getType(); } - virtual void print(raw_ostream &OS) const; + //===--------------------------------------------------------------------===// + /// SCEVCommutativeExpr - This node is the base class for n'ary commutative + /// operators. + /// + class SCEVCommutativeExpr : public SCEVNAryExpr { + protected: + SCEVCommutativeExpr(const FoldingSetNodeIDRef ID, + enum SCEVTypes T, const SCEV *const *O, size_t N) + : SCEVNAryExpr(ID, T, O, N) {} + public: /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVCommutativeExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scAddExpr || S->getSCEVType() == scMulExpr || S->getSCEVType() == scSMaxExpr || S->getSCEVType() == scUMaxExpr; } + + /// Set flags for a non-recurrence without clearing previously set flags. + void setNoWrapFlags(NoWrapFlags Flags) { + SubclassData |= Flags; + } }; @@ -281,15 +207,20 @@ namespace llvm { class SCEVAddExpr : public SCEVCommutativeExpr { friend class ScalarEvolution; - explicit SCEVAddExpr(const std::vector &ops) - : SCEVCommutativeExpr(scAddExpr, ops) { + SCEVAddExpr(const FoldingSetNodeIDRef ID, + const SCEV *const *O, size_t N) + : SCEVCommutativeExpr(ID, scAddExpr, O, N) { } public: - virtual const char *getOperationStr() const { return " + "; } + Type *getType() const { + // Use the type of the last operand, which is likely to be a pointer + // type, if there is one. This doesn't usually matter, but it can help + // reduce casts when the expressions are expanded. + return getOperand(getNumOperands() - 1)->getType(); + } /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVAddExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scAddExpr; } @@ -301,15 +232,13 @@ namespace llvm { class SCEVMulExpr : public SCEVCommutativeExpr { friend class ScalarEvolution; - explicit SCEVMulExpr(const std::vector &ops) - : SCEVCommutativeExpr(scMulExpr, ops) { + SCEVMulExpr(const FoldingSetNodeIDRef ID, + const SCEV *const *O, size_t N) + : SCEVCommutativeExpr(ID, scMulExpr, O, N) { } public: - virtual const char *getOperationStr() const { return " * "; } - /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVMulExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scMulExpr; } @@ -322,43 +251,25 @@ namespace llvm { class SCEVUDivExpr : public SCEV { friend class ScalarEvolution; - SCEVHandle LHS, RHS; - SCEVUDivExpr(const SCEVHandle &lhs, const SCEVHandle &rhs) - : SCEV(scUDivExpr), LHS(lhs), RHS(rhs) {} + const SCEV *LHS; + const SCEV *RHS; + SCEVUDivExpr(const FoldingSetNodeIDRef ID, const SCEV *lhs, const SCEV *rhs) + : SCEV(ID, scUDivExpr), LHS(lhs), RHS(rhs) {} - virtual ~SCEVUDivExpr(); public: - const SCEVHandle &getLHS() const { return LHS; } - const SCEVHandle &getRHS() const { return RHS; } - - virtual bool isLoopInvariant(const Loop *L) const { - return LHS->isLoopInvariant(L) && RHS->isLoopInvariant(L); - } - - virtual bool hasComputableLoopEvolution(const Loop *L) const { - return LHS->hasComputableLoopEvolution(L) && - RHS->hasComputableLoopEvolution(L); - } + const SCEV *getLHS() const { return LHS; } + const SCEV *getRHS() const { return RHS; } - SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym, - const SCEVHandle &Conc, - ScalarEvolution &SE) const { - SCEVHandle L = LHS->replaceSymbolicValuesWithConcrete(Sym, Conc, SE); - SCEVHandle R = RHS->replaceSymbolicValuesWithConcrete(Sym, Conc, SE); - if (L == LHS && R == RHS) - return this; - else - return SE.getUDivExpr(L, R); + Type *getType() const { + // In most cases the types of LHS and RHS will be the same, but in some + // crazy cases one or the other may be a pointer. ScalarEvolution doesn't + // depend on the type for correctness, but handling types carefully can + // avoid extra casts in the SCEVExpander. The LHS is more likely to be + // a pointer type than the RHS, so use the RHS' type here. + return getRHS()->getType(); } - bool dominates(BasicBlock *BB, DominatorTree *DT) const; - - virtual const Type *getType() const; - - void print(raw_ostream &OS) const; - /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVUDivExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scUDivExpr; } @@ -367,70 +278,64 @@ namespace llvm { //===--------------------------------------------------------------------===// /// SCEVAddRecExpr - This node represents a polynomial recurrence on the trip - /// count of the specified loop. + /// count of the specified loop. This is the primary focus of the + /// ScalarEvolution framework; all the other SCEV subclasses are mostly just + /// supporting infrastructure to allow SCEVAddRecExpr expressions to be + /// created and analyzed. /// /// All operands of an AddRec are required to be loop invariant. /// - class SCEVAddRecExpr : public SCEV { + class SCEVAddRecExpr : public SCEVNAryExpr { friend class ScalarEvolution; - std::vector Operands; const Loop *L; - SCEVAddRecExpr(const std::vector &ops, const Loop *l) - : SCEV(scAddRecExpr), Operands(ops), L(l) { - for (size_t i = 0, e = Operands.size(); i != e; ++i) - assert(Operands[i]->isLoopInvariant(l) && - "Operands of AddRec must be loop-invariant!"); - } - ~SCEVAddRecExpr(); - public: - typedef std::vector::const_iterator op_iterator; - op_iterator op_begin() const { return Operands.begin(); } - op_iterator op_end() const { return Operands.end(); } + SCEVAddRecExpr(const FoldingSetNodeIDRef ID, + const SCEV *const *O, size_t N, const Loop *l) + : SCEVNAryExpr(ID, scAddRecExpr, O, N), L(l) {} - unsigned getNumOperands() const { return (unsigned)Operands.size(); } - const SCEVHandle &getOperand(unsigned i) const { return Operands[i]; } - const SCEVHandle &getStart() const { return Operands[0]; } + public: + const SCEV *getStart() const { return Operands[0]; } const Loop *getLoop() const { return L; } - /// getStepRecurrence - This method constructs and returns the recurrence /// indicating how much this expression steps by. If this is a polynomial /// of degree N, it returns a chrec of degree N-1. - SCEVHandle getStepRecurrence(ScalarEvolution &SE) const { + /// We cannot determine whether the step recurrence has self-wraparound. + const SCEV *getStepRecurrence(ScalarEvolution &SE) const { if (isAffine()) return getOperand(1); - return SE.getAddRecExpr(std::vector(op_begin()+1,op_end()), - getLoop()); - } - - virtual bool hasComputableLoopEvolution(const Loop *QL) const { - if (L == QL) return true; - return false; + return SE.getAddRecExpr(SmallVector(op_begin()+1, + op_end()), + getLoop(), FlagAnyWrap); } - virtual bool isLoopInvariant(const Loop *QueryLoop) const; - - virtual const Type *getType() const { return Operands[0]->getType(); } - - /// isAffine - Return true if this is an affine AddRec (i.e., it represents - /// an expressions A+B*x where A and B are loop invariant values. + /// isAffine - Return true if this represents an expression + /// A + B*x where A and B are loop invariant values. bool isAffine() const { // We know that the start value is invariant. This expression is thus // affine iff the step is also invariant. return getNumOperands() == 2; } - /// isQuadratic - Return true if this is an quadratic AddRec (i.e., it - /// represents an expressions A+B*x+C*x^2 where A, B and C are loop - /// invariant values. This corresponds to an addrec of the form {L,+,M,+,N} + /// isQuadratic - Return true if this represents an expression + /// A + B*x + C*x^2 where A, B and C are loop invariant values. + /// This corresponds to an addrec of the form {L,+,M,+,N} bool isQuadratic() const { return getNumOperands() == 3; } + /// Set flags for a recurrence without clearing any previously set flags. + /// For AddRec, either NUW or NSW implies NW. Keep track of this fact here + /// to make it easier to propagate flags. + void setNoWrapFlags(NoWrapFlags Flags) { + if (Flags & (FlagNUW | FlagNSW)) + Flags = ScalarEvolution::setFlags(Flags, FlagNW); + SubclassData |= Flags; + } + /// evaluateAtIteration - Return the value of this chain of recurrences at /// the specified iteration number. - SCEVHandle evaluateAtIteration(SCEVHandle It, ScalarEvolution &SE) const; + const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const; /// getNumIterationsInRange - Return the number of iterations of this loop /// that produce values in the specified constant range. Another way of @@ -438,40 +343,36 @@ namespace llvm { /// value is not in the condition, thus computing the exit count. If the /// iteration count can't be computed, an instance of SCEVCouldNotCompute is /// returned. - SCEVHandle getNumIterationsInRange(ConstantRange Range, + const SCEV *getNumIterationsInRange(ConstantRange Range, ScalarEvolution &SE) const; - SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym, - const SCEVHandle &Conc, - ScalarEvolution &SE) const; - - bool dominates(BasicBlock *BB, DominatorTree *DT) const; - - virtual void print(raw_ostream &OS) const; + /// getPostIncExpr - Return an expression representing the value of + /// this expression one iteration of the loop ahead. + const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const { + return cast(SE.getAddExpr(this, getStepRecurrence(SE))); + } /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVAddRecExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scAddRecExpr; } }; - //===--------------------------------------------------------------------===// /// SCEVSMaxExpr - This class represents a signed maximum selection. /// class SCEVSMaxExpr : public SCEVCommutativeExpr { friend class ScalarEvolution; - explicit SCEVSMaxExpr(const std::vector &ops) - : SCEVCommutativeExpr(scSMaxExpr, ops) { + SCEVSMaxExpr(const FoldingSetNodeIDRef ID, + const SCEV *const *O, size_t N) + : SCEVCommutativeExpr(ID, scSMaxExpr, O, N) { + // Max never overflows. + setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW)); } public: - virtual const char *getOperationStr() const { return " smax "; } - /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVSMaxExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scSMaxExpr; } @@ -484,57 +385,61 @@ namespace llvm { class SCEVUMaxExpr : public SCEVCommutativeExpr { friend class ScalarEvolution; - explicit SCEVUMaxExpr(const std::vector &ops) - : SCEVCommutativeExpr(scUMaxExpr, ops) { + SCEVUMaxExpr(const FoldingSetNodeIDRef ID, + const SCEV *const *O, size_t N) + : SCEVCommutativeExpr(ID, scUMaxExpr, O, N) { + // Max never overflows. + setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW)); } public: - virtual const char *getOperationStr() const { return " umax "; } - /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVUMaxExpr *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scUMaxExpr; } }; - //===--------------------------------------------------------------------===// /// SCEVUnknown - This means that we are dealing with an entirely unknown SCEV - /// value, and only represent it as it's LLVM Value. This is the "bottom" + /// value, and only represent it as its LLVM Value. This is the "bottom" /// value for the analysis. /// - class SCEVUnknown : public SCEV { + class SCEVUnknown final : public SCEV, private CallbackVH { friend class ScalarEvolution; - Value *V; - explicit SCEVUnknown(Value *v) : SCEV(scUnknown), V(v) {} + // Implement CallbackVH. + void deleted() override; + void allUsesReplacedWith(Value *New) override; - protected: - ~SCEVUnknown(); - public: - Value *getValue() const { return V; } + /// SE - The parent ScalarEvolution value. This is used to update + /// the parent's maps when the value associated with a SCEVUnknown + /// is deleted or RAUW'd. + ScalarEvolution *SE; - virtual bool isLoopInvariant(const Loop *L) const; - virtual bool hasComputableLoopEvolution(const Loop *QL) const { - return false; // not computable - } + /// Next - The next pointer in the linked list of all + /// SCEVUnknown instances owned by a ScalarEvolution. + SCEVUnknown *Next; - SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym, - const SCEVHandle &Conc, - ScalarEvolution &SE) const { - if (&*Sym == this) return Conc; - return this; - } + SCEVUnknown(const FoldingSetNodeIDRef ID, Value *V, + ScalarEvolution *se, SCEVUnknown *next) : + SCEV(ID, scUnknown), CallbackVH(V), SE(se), Next(next) {} - bool dominates(BasicBlock *BB, DominatorTree *DT) const; + public: + Value *getValue() const { return getValPtr(); } - virtual const Type *getType() const; + /// isSizeOf, isAlignOf, isOffsetOf - Test whether this is a special + /// constant representing a type size, alignment, or field offset in + /// a target-independent manner, and hasn't happened to have been + /// folded with other operations into something unrecognizable. This + /// is mainly only useful for pretty-printing and other situations + /// where it isn't absolutely required for these to succeed. + bool isSizeOf(Type *&AllocTy) const; + bool isAlignOf(Type *&AllocTy) const; + bool isOffsetOf(Type *&STy, Constant *&FieldNo) const; - virtual void print(raw_ostream &OS) const; + Type *getType() const { return getValPtr()->getType(); } /// Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const SCEVUnknown *S) { return true; } static inline bool classof(const SCEV *S) { return S->getSCEVType() == scUnknown; } @@ -571,17 +476,233 @@ namespace llvm { case scCouldNotCompute: return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S); default: - assert(0 && "Unknown SCEV type!"); - abort(); + llvm_unreachable("Unknown SCEV type!"); } } RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) { - assert(0 && "Invalid use of SCEVCouldNotCompute!"); - abort(); - return RetVal(); + llvm_unreachable("Invalid use of SCEVCouldNotCompute!"); } }; + + /// Visit all nodes in the expression tree using worklist traversal. + /// + /// Visitor implements: + /// // return true to follow this node. + /// bool follow(const SCEV *S); + /// // return true to terminate the search. + /// bool isDone(); + template + class SCEVTraversal { + SV &Visitor; + SmallVector Worklist; + SmallPtrSet Visited; + + void push(const SCEV *S) { + if (Visited.insert(S).second && Visitor.follow(S)) + Worklist.push_back(S); + } + public: + SCEVTraversal(SV& V): Visitor(V) {} + + void visitAll(const SCEV *Root) { + push(Root); + while (!Worklist.empty() && !Visitor.isDone()) { + const SCEV *S = Worklist.pop_back_val(); + + switch (S->getSCEVType()) { + case scConstant: + case scUnknown: + break; + case scTruncate: + case scZeroExtend: + case scSignExtend: + push(cast(S)->getOperand()); + break; + case scAddExpr: + case scMulExpr: + case scSMaxExpr: + case scUMaxExpr: + case scAddRecExpr: { + const SCEVNAryExpr *NAry = cast(S); + for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), + E = NAry->op_end(); I != E; ++I) { + push(*I); + } + break; + } + case scUDivExpr: { + const SCEVUDivExpr *UDiv = cast(S); + push(UDiv->getLHS()); + push(UDiv->getRHS()); + break; + } + case scCouldNotCompute: + llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!"); + default: + llvm_unreachable("Unknown SCEV kind!"); + } + } + } + }; + + /// Use SCEVTraversal to visit all nodes in the given expression tree. + template + void visitAll(const SCEV *Root, SV& Visitor) { + SCEVTraversal T(Visitor); + T.visitAll(Root); + } + + /// Recursively visits a SCEV expression and re-writes it. + template + class SCEVRewriteVisitor : public SCEVVisitor { + protected: + ScalarEvolution &SE; + public: + SCEVRewriteVisitor(ScalarEvolution &SE) : SE(SE) {} + + const SCEV *visitConstant(const SCEVConstant *Constant) { + return Constant; + } + + const SCEV *visitTruncateExpr(const SCEVTruncateExpr *Expr) { + const SCEV *Operand = ((SC*)this)->visit(Expr->getOperand()); + return SE.getTruncateExpr(Operand, Expr->getType()); + } + + const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) { + const SCEV *Operand = ((SC*)this)->visit(Expr->getOperand()); + return SE.getZeroExtendExpr(Operand, Expr->getType()); + } + + const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) { + const SCEV *Operand = ((SC*)this)->visit(Expr->getOperand()); + return SE.getSignExtendExpr(Operand, Expr->getType()); + } + + const SCEV *visitAddExpr(const SCEVAddExpr *Expr) { + SmallVector Operands; + for (int i = 0, e = Expr->getNumOperands(); i < e; ++i) + Operands.push_back(((SC*)this)->visit(Expr->getOperand(i))); + return SE.getAddExpr(Operands); + } + + const SCEV *visitMulExpr(const SCEVMulExpr *Expr) { + SmallVector Operands; + for (int i = 0, e = Expr->getNumOperands(); i < e; ++i) + Operands.push_back(((SC*)this)->visit(Expr->getOperand(i))); + return SE.getMulExpr(Operands); + } + + const SCEV *visitUDivExpr(const SCEVUDivExpr *Expr) { + return SE.getUDivExpr(((SC*)this)->visit(Expr->getLHS()), + ((SC*)this)->visit(Expr->getRHS())); + } + + const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { + SmallVector Operands; + for (int i = 0, e = Expr->getNumOperands(); i < e; ++i) + Operands.push_back(((SC*)this)->visit(Expr->getOperand(i))); + return SE.getAddRecExpr(Operands, Expr->getLoop(), + Expr->getNoWrapFlags()); + } + + const SCEV *visitSMaxExpr(const SCEVSMaxExpr *Expr) { + SmallVector Operands; + for (int i = 0, e = Expr->getNumOperands(); i < e; ++i) + Operands.push_back(((SC*)this)->visit(Expr->getOperand(i))); + return SE.getSMaxExpr(Operands); + } + + const SCEV *visitUMaxExpr(const SCEVUMaxExpr *Expr) { + SmallVector Operands; + for (int i = 0, e = Expr->getNumOperands(); i < e; ++i) + Operands.push_back(((SC*)this)->visit(Expr->getOperand(i))); + return SE.getUMaxExpr(Operands); + } + + const SCEV *visitUnknown(const SCEVUnknown *Expr) { + return Expr; + } + + const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) { + return Expr; + } + }; + + typedef DenseMap ValueToValueMap; + + /// The SCEVParameterRewriter takes a scalar evolution expression and updates + /// the SCEVUnknown components following the Map (Value -> Value). + class SCEVParameterRewriter : public SCEVRewriteVisitor { + public: + static const SCEV *rewrite(const SCEV *Scev, ScalarEvolution &SE, + ValueToValueMap &Map, + bool InterpretConsts = false) { + SCEVParameterRewriter Rewriter(SE, Map, InterpretConsts); + return Rewriter.visit(Scev); + } + + SCEVParameterRewriter(ScalarEvolution &SE, ValueToValueMap &M, bool C) + : SCEVRewriteVisitor(SE), Map(M), InterpretConsts(C) {} + + const SCEV *visitUnknown(const SCEVUnknown *Expr) { + Value *V = Expr->getValue(); + if (Map.count(V)) { + Value *NV = Map[V]; + if (InterpretConsts && isa(NV)) + return SE.getConstant(cast(NV)); + return SE.getUnknown(NV); + } + return Expr; + } + + private: + ValueToValueMap ⤅ + bool InterpretConsts; + }; + + typedef DenseMap LoopToScevMapT; + + /// The SCEVLoopAddRecRewriter takes a scalar evolution expression and applies + /// the Map (Loop -> SCEV) to all AddRecExprs. + class SCEVLoopAddRecRewriter + : public SCEVRewriteVisitor { + public: + static const SCEV *rewrite(const SCEV *Scev, LoopToScevMapT &Map, + ScalarEvolution &SE) { + SCEVLoopAddRecRewriter Rewriter(SE, Map); + return Rewriter.visit(Scev); + } + + SCEVLoopAddRecRewriter(ScalarEvolution &SE, LoopToScevMapT &M) + : SCEVRewriteVisitor(SE), Map(M) {} + + const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { + SmallVector Operands; + for (int i = 0, e = Expr->getNumOperands(); i < e; ++i) + Operands.push_back(visit(Expr->getOperand(i))); + + const Loop *L = Expr->getLoop(); + const SCEV *Res = SE.getAddRecExpr(Operands, L, Expr->getNoWrapFlags()); + + if (0 == Map.count(L)) + return Res; + + const SCEVAddRecExpr *Rec = cast(Res); + return Rec->evaluateAtIteration(Map[L], SE); + } + + private: + LoopToScevMapT ⤅ + }; + +/// Applies the Map (Loop -> SCEV) to the given Scev. +static inline const SCEV *apply(const SCEV *Scev, LoopToScevMapT &Map, + ScalarEvolution &SE) { + return SCEVLoopAddRecRewriter::rewrite(Scev, Map, SE); +} + } #endif