include/llvm/Analysis/ScalarEvolutionExpressions.h - llvm - Git at Google

 //===- llvm/Analysis/ScalarEvolutionExpressions.h - SCEV Exprs --*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file defines the classes used to represent and build scalar expressions.
 //
 //===----------------------------------------------------------------------===//

 #ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H
 #define LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H

 #include "llvm/Analysis/ScalarEvolution.h"

 namespace llvm {
   class ConstantInt;
   class ConstantRange;
   class APInt;

   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
   };

   //===--------------------------------------------------------------------===//
   /// SCEVConstant - This class represents a constant integer value.
   ///
   class SCEVConstant : public SCEV {
     friend class ScalarEvolution;

     ConstantInt *V;
     explicit SCEVConstant(ConstantInt *v) : SCEV(scConstant), V(v) {}

     virtual ~SCEVConstant();
   public:
     ConstantInt *getValue() const { return V; }

     virtual bool isLoopInvariant(const Loop *L) const {
       return true;
     }

     virtual bool hasComputableLoopEvolution(const Loop *L) const {
       return false;  // Not loop variant
     }

     virtual const Type *getType() const;

     SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
                                                  const SCEVHandle &Conc,
                                                  ScalarEvolution &SE) const {
       return this;
     }

     virtual void print(std::ostream &OS) const;
     void print(std::ostream *OS) const { if (OS) print(*OS); }

     /// 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;
     }
   };

   //===--------------------------------------------------------------------===//
   /// SCEVTruncateExpr - This class represents a truncation of an integer value
   /// to a smaller integer value.
   ///
   class SCEVTruncateExpr : public SCEV {
     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 void print(std::ostream &OS) const;
     void print(std::ostream *OS) const { if (OS) print(*OS); }

     /// 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;
     }
   };

   //===--------------------------------------------------------------------===//
   /// SCEVZeroExtendExpr - This class represents a zero extension of a small
   /// integer value to a larger integer value.
   ///
   class SCEVZeroExtendExpr : public SCEV {
     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);
     }

     virtual void print(std::ostream &OS) const;
     void print(std::ostream *OS) const { if (OS) print(*OS); }

     /// 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;
     }
   };

   //===--------------------------------------------------------------------===//
   /// SCEVSignExtendExpr - This class represents a sign extension of a small
   /// integer value to a larger integer value.
   ///
   class SCEVSignExtendExpr : public SCEV {
     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);
     }

     virtual void print(std::ostream &OS) const;
     void print(std::ostream *OS) const { if (OS) print(*OS); }

     /// 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;
     }
   };


   //===--------------------------------------------------------------------===//
   /// SCEVCommutativeExpr - This node is the base class for n'ary commutative
   /// operators.
   ///
   class SCEVCommutativeExpr : public SCEV {
     friend class ScalarEvolution;

     std::vector<SCEVHandle> Operands;

   protected:
     SCEVCommutativeExpr(enum SCEVTypes T, const std::vector<SCEVHandle> &ops)
       : SCEV(T) {
       Operands.reserve(ops.size());
       Operands.insert(Operands.end(), ops.begin(), ops.end());
     }
     ~SCEVCommutativeExpr();

   public:
     unsigned getNumOperands() const { return (unsigned)Operands.size(); }
     const SCEVHandle &getOperand(unsigned i) const {
       assert(i < Operands.size() && "Operand index out of range!");
       return Operands[i];
     }

     const std::vector<SCEVHandle> &getOperands() const { return Operands; }
     typedef std::vector<SCEVHandle>::const_iterator op_iterator;
     op_iterator op_begin() const { return Operands.begin(); }
     op_iterator op_end() const { return Operands.end(); }


     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;
     }

     // 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;
     }

     SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
                                                  const SCEVHandle &Conc,
                                                  ScalarEvolution &SE) const;

     virtual const char *getOperationStr() const = 0;

     virtual const Type *getType() const { return getOperand(0)->getType(); }
     virtual void print(std::ostream &OS) const;
     void print(std::ostream *OS) const { if (OS) print(*OS); }

     /// 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;
     }
   };


   //===--------------------------------------------------------------------===//
   /// SCEVAddExpr - This node represents an addition of some number of SCEVs.
   ///
   class SCEVAddExpr : public SCEVCommutativeExpr {
     friend class ScalarEvolution;

     explicit SCEVAddExpr(const std::vector<SCEVHandle> &ops)
       : SCEVCommutativeExpr(scAddExpr, ops) {
     }

   public:
     virtual const char *getOperationStr() const { return " + "; }

     /// 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;
     }
   };

   //===--------------------------------------------------------------------===//
   /// SCEVMulExpr - This node represents multiplication of some number of SCEVs.
   ///
   class SCEVMulExpr : public SCEVCommutativeExpr {
     friend class ScalarEvolution;

     explicit SCEVMulExpr(const std::vector<SCEVHandle> &ops)
       : SCEVCommutativeExpr(scMulExpr, ops) {
     }

   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;
     }
   };


   //===--------------------------------------------------------------------===//
   /// SCEVUDivExpr - This class represents a binary unsigned division operation.
   ///
   class SCEVUDivExpr : public SCEV {
     friend class ScalarEvolution;

     SCEVHandle LHS, RHS;
     SCEVUDivExpr(const SCEVHandle &lhs, const SCEVHandle &rhs)
       : SCEV(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);
     }

     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);
     }


     virtual const Type *getType() const;

     void print(std::ostream &OS) const;
     void print(std::ostream *OS) const { if (OS) print(*OS); }

     /// 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;
     }
   };


   //===--------------------------------------------------------------------===//
   /// SCEVAddRecExpr - This node represents a polynomial recurrence on the trip
   /// count of the specified loop.
   ///
   /// All operands of an AddRec are required to be loop invariant.
   ///
   class SCEVAddRecExpr : public SCEV {
     friend class ScalarEvolution;

     std::vector<SCEVHandle> Operands;
     const Loop *L;

     SCEVAddRecExpr(const std::vector<SCEVHandle> &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<SCEVHandle>::const_iterator op_iterator;
     op_iterator op_begin() const { return Operands.begin(); }
     op_iterator op_end() const { return Operands.end(); }

     unsigned getNumOperands() const { return (unsigned)Operands.size(); }
     const SCEVHandle &getOperand(unsigned i) const { return Operands[i]; }
     const SCEVHandle &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 {
       if (isAffine()) return getOperand(1);
       return SE.getAddRecExpr(std::vector<SCEVHandle>(op_begin()+1,op_end()),
                               getLoop());
     }

     virtual bool hasComputableLoopEvolution(const Loop *QL) const {
       if (L == QL) return true;
       return false;
     }

     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.
     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}
     bool isQuadratic() const {
       return getNumOperands() == 3;
     }

     /// evaluateAtIteration - Return the value of this chain of recurrences at
     /// the specified iteration number.
     SCEVHandle evaluateAtIteration(SCEVHandle It, ScalarEvolution &SE) const;

     /// getNumIterationsInRange - Return the number of iterations of this loop
     /// that produce values in the specified constant range.  Another way of
     /// looking at this is that it returns the first iteration number where the
     /// 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,
                                        ScalarEvolution &SE) const;

     SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
                                                  const SCEVHandle &Conc,
                                                  ScalarEvolution &SE) const;

     virtual void print(std::ostream &OS) const;
     void print(std::ostream *OS) const { if (OS) print(*OS); }

     /// 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<SCEVHandle> &ops)
       : SCEVCommutativeExpr(scSMaxExpr, ops) {
     }

   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;
     }
   };


   //===--------------------------------------------------------------------===//
   /// SCEVUMaxExpr - This class represents an unsigned maximum selection.
   ///
   class SCEVUMaxExpr : public SCEVCommutativeExpr {
     friend class ScalarEvolution;

     explicit SCEVUMaxExpr(const std::vector<SCEVHandle> &ops)
       : SCEVCommutativeExpr(scUMaxExpr, ops) {
     }

   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 for the analysis.
   ///
   class SCEVUnknown : public SCEV {
     friend class ScalarEvolution;

     Value *V;
     explicit SCEVUnknown(Value *v) : SCEV(scUnknown), V(v) {}

   protected:
     ~SCEVUnknown();
   public:
     Value *getValue() const { return V; }

     virtual bool isLoopInvariant(const Loop *L) const;
     virtual bool hasComputableLoopEvolution(const Loop *QL) const {
       return false; // not computable
     }

     SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
                                                  const SCEVHandle &Conc,
                                                  ScalarEvolution &SE) const {
       if (&*Sym == this) return Conc;
       return this;
     }

     virtual const Type *getType() const;

     virtual void print(std::ostream &OS) const;
     void print(std::ostream *OS) const { if (OS) print(*OS); }

     /// 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;
     }
   };

   /// SCEVVisitor - This class defines a simple visitor class that may be used
   /// for various SCEV analysis purposes.
   template<typename SC, typename RetVal=void>
   struct SCEVVisitor {
     RetVal visit(SCEV *S) {
       switch (S->getSCEVType()) {
       case scConstant:
         return ((SC*)this)->visitConstant((SCEVConstant*)S);
       case scTruncate:
         return ((SC*)this)->visitTruncateExpr((SCEVTruncateExpr*)S);
       case scZeroExtend:
         return ((SC*)this)->visitZeroExtendExpr((SCEVZeroExtendExpr*)S);
       case scSignExtend:
         return ((SC*)this)->visitSignExtendExpr((SCEVSignExtendExpr*)S);
       case scAddExpr:
         return ((SC*)this)->visitAddExpr((SCEVAddExpr*)S);
       case scMulExpr:
         return ((SC*)this)->visitMulExpr((SCEVMulExpr*)S);
       case scUDivExpr:
         return ((SC*)this)->visitUDivExpr((SCEVUDivExpr*)S);
       case scAddRecExpr:
         return ((SC*)this)->visitAddRecExpr((SCEVAddRecExpr*)S);
       case scSMaxExpr:
         return ((SC*)this)->visitSMaxExpr((SCEVSMaxExpr*)S);
       case scUMaxExpr:
         return ((SC*)this)->visitUMaxExpr((SCEVUMaxExpr*)S);
       case scUnknown:
         return ((SC*)this)->visitUnknown((SCEVUnknown*)S);
       case scCouldNotCompute:
         return ((SC*)this)->visitCouldNotCompute((SCEVCouldNotCompute*)S);
       default:
         assert(0 && "Unknown SCEV type!");
         abort();
       }
     }

     RetVal visitCouldNotCompute(SCEVCouldNotCompute *S) {
       assert(0 && "Invalid use of SCEVCouldNotCompute!");
       abort();
       return RetVal();
     }
   };
 }

 #endif
	//===- llvm/Analysis/ScalarEvolutionExpressions.h - SCEV Exprs --- C++ --===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file defines the classes used to represent and build scalar expressions.
	//
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H
	#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H

	#include "llvm/Analysis/ScalarEvolution.h"

	namespace llvm {
	class ConstantInt;
	class ConstantRange;
	class APInt;

	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
	};

	//===--------------------------------------------------------------------===//
	/// SCEVConstant - This class represents a constant integer value.
	///
	class SCEVConstant : public SCEV {
	friend class ScalarEvolution;

	ConstantInt *V;
	explicit SCEVConstant(ConstantInt *v) : SCEV(scConstant), V(v) {}

	virtual ~SCEVConstant();
	public:
	ConstantInt *getValue() const { return V; }

	virtual bool isLoopInvariant(const Loop *L) const {
	return true;
	}

	virtual bool hasComputableLoopEvolution(const Loop *L) const {
	return false; // Not loop variant
	}

	virtual const Type *getType() const;

	SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
	const SCEVHandle &Conc,
	ScalarEvolution &SE) const {
	return this;
	}

	virtual void print(std::ostream &OS) const;
	void print(std::ostream OS) const { if (OS) print(OS); }

	/// 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;
	}
	};

	//===--------------------------------------------------------------------===//
	/// SCEVTruncateExpr - This class represents a truncation of an integer value
	/// to a smaller integer value.
	///
	class SCEVTruncateExpr : public SCEV {
	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 void print(std::ostream &OS) const;
	void print(std::ostream OS) const { if (OS) print(OS); }

	/// 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;
	}
	};

	//===--------------------------------------------------------------------===//
	/// SCEVZeroExtendExpr - This class represents a zero extension of a small
	/// integer value to a larger integer value.
	///
	class SCEVZeroExtendExpr : public SCEV {
	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);
	}

	virtual void print(std::ostream &OS) const;
	void print(std::ostream OS) const { if (OS) print(OS); }

	/// 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;
	}
	};

	//===--------------------------------------------------------------------===//
	/// SCEVSignExtendExpr - This class represents a sign extension of a small
	/// integer value to a larger integer value.
	///
	class SCEVSignExtendExpr : public SCEV {
	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);
	}

	virtual void print(std::ostream &OS) const;
	void print(std::ostream OS) const { if (OS) print(OS); }

	/// 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;
	}
	};


	//===--------------------------------------------------------------------===//
	/// SCEVCommutativeExpr - This node is the base class for n'ary commutative
	/// operators.
	///
	class SCEVCommutativeExpr : public SCEV {
	friend class ScalarEvolution;

	std::vector<SCEVHandle> Operands;

	protected:
	SCEVCommutativeExpr(enum SCEVTypes T, const std::vector<SCEVHandle> &ops)
	: SCEV(T) {
	Operands.reserve(ops.size());
	Operands.insert(Operands.end(), ops.begin(), ops.end());
	}
	~SCEVCommutativeExpr();

	public:
	unsigned getNumOperands() const { return (unsigned)Operands.size(); }
	const SCEVHandle &getOperand(unsigned i) const {
	assert(i < Operands.size() && "Operand index out of range!");
	return Operands[i];
	}

	const std::vector<SCEVHandle> &getOperands() const { return Operands; }
	typedef std::vector<SCEVHandle>::const_iterator op_iterator;
	op_iterator op_begin() const { return Operands.begin(); }
	op_iterator op_end() const { return Operands.end(); }


	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;
	}

	// 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;
	}

	SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
	const SCEVHandle &Conc,
	ScalarEvolution &SE) const;

	virtual const char *getOperationStr() const = 0;

	virtual const Type *getType() const { return getOperand(0)->getType(); }
	virtual void print(std::ostream &OS) const;
	void print(std::ostream OS) const { if (OS) print(OS); }

	/// 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;
	}
	};


	//===--------------------------------------------------------------------===//
	/// SCEVAddExpr - This node represents an addition of some number of SCEVs.
	///
	class SCEVAddExpr : public SCEVCommutativeExpr {
	friend class ScalarEvolution;

	explicit SCEVAddExpr(const std::vector<SCEVHandle> &ops)
	: SCEVCommutativeExpr(scAddExpr, ops) {
	}

	public:
	virtual const char *getOperationStr() const { return " + "; }

	/// 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;
	}
	};

	//===--------------------------------------------------------------------===//
	/// SCEVMulExpr - This node represents multiplication of some number of SCEVs.
	///
	class SCEVMulExpr : public SCEVCommutativeExpr {
	friend class ScalarEvolution;

	explicit SCEVMulExpr(const std::vector<SCEVHandle> &ops)
	: SCEVCommutativeExpr(scMulExpr, ops) {
	}

	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;
	}
	};


	//===--------------------------------------------------------------------===//
	/// SCEVUDivExpr - This class represents a binary unsigned division operation.
	///
	class SCEVUDivExpr : public SCEV {
	friend class ScalarEvolution;

	SCEVHandle LHS, RHS;
	SCEVUDivExpr(const SCEVHandle &lhs, const SCEVHandle &rhs)
	: SCEV(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);
	}

	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);
	}


	virtual const Type *getType() const;

	void print(std::ostream &OS) const;
	void print(std::ostream OS) const { if (OS) print(OS); }

	/// 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;
	}
	};


	//===--------------------------------------------------------------------===//
	/// SCEVAddRecExpr - This node represents a polynomial recurrence on the trip
	/// count of the specified loop.
	///
	/// All operands of an AddRec are required to be loop invariant.
	///
	class SCEVAddRecExpr : public SCEV {
	friend class ScalarEvolution;

	std::vector<SCEVHandle> Operands;
	const Loop *L;

	SCEVAddRecExpr(const std::vector<SCEVHandle> &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<SCEVHandle>::const_iterator op_iterator;
	op_iterator op_begin() const { return Operands.begin(); }
	op_iterator op_end() const { return Operands.end(); }

	unsigned getNumOperands() const { return (unsigned)Operands.size(); }
	const SCEVHandle &getOperand(unsigned i) const { return Operands[i]; }
	const SCEVHandle &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 {
	if (isAffine()) return getOperand(1);
	return SE.getAddRecExpr(std::vector<SCEVHandle>(op_begin()+1,op_end()),
	getLoop());
	}

	virtual bool hasComputableLoopEvolution(const Loop *QL) const {
	if (L == QL) return true;
	return false;
	}

	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.
	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+Bx+Cx^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;
	}

	/// evaluateAtIteration - Return the value of this chain of recurrences at
	/// the specified iteration number.
	SCEVHandle evaluateAtIteration(SCEVHandle It, ScalarEvolution &SE) const;

	/// getNumIterationsInRange - Return the number of iterations of this loop
	/// that produce values in the specified constant range. Another way of
	/// looking at this is that it returns the first iteration number where the
	/// 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,
	ScalarEvolution &SE) const;

	SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
	const SCEVHandle &Conc,
	ScalarEvolution &SE) const;

	virtual void print(std::ostream &OS) const;
	void print(std::ostream OS) const { if (OS) print(OS); }

	/// 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<SCEVHandle> &ops)
	: SCEVCommutativeExpr(scSMaxExpr, ops) {
	}

	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;
	}
	};


	//===--------------------------------------------------------------------===//
	/// SCEVUMaxExpr - This class represents an unsigned maximum selection.
	///
	class SCEVUMaxExpr : public SCEVCommutativeExpr {
	friend class ScalarEvolution;

	explicit SCEVUMaxExpr(const std::vector<SCEVHandle> &ops)
	: SCEVCommutativeExpr(scUMaxExpr, ops) {
	}

	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 for the analysis.
	///
	class SCEVUnknown : public SCEV {
	friend class ScalarEvolution;

	Value *V;
	explicit SCEVUnknown(Value *v) : SCEV(scUnknown), V(v) {}

	protected:
	~SCEVUnknown();
	public:
	Value *getValue() const { return V; }

	virtual bool isLoopInvariant(const Loop *L) const;
	virtual bool hasComputableLoopEvolution(const Loop *QL) const {
	return false; // not computable
	}

	SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
	const SCEVHandle &Conc,
	ScalarEvolution &SE) const {
	if (&*Sym == this) return Conc;
	return this;
	}

	virtual const Type *getType() const;

	virtual void print(std::ostream &OS) const;
	void print(std::ostream OS) const { if (OS) print(OS); }

	/// 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;
	}
	};

	/// SCEVVisitor - This class defines a simple visitor class that may be used
	/// for various SCEV analysis purposes.
	template<typename SC, typename RetVal=void>
	struct SCEVVisitor {
	RetVal visit(SCEV *S) {
	switch (S->getSCEVType()) {
	case scConstant:
	return ((SC)this)->visitConstant((SCEVConstant)S);
	case scTruncate:
	return ((SC)this)->visitTruncateExpr((SCEVTruncateExpr)S);
	case scZeroExtend:
	return ((SC)this)->visitZeroExtendExpr((SCEVZeroExtendExpr)S);
	case scSignExtend:
	return ((SC)this)->visitSignExtendExpr((SCEVSignExtendExpr)S);
	case scAddExpr:
	return ((SC)this)->visitAddExpr((SCEVAddExpr)S);
	case scMulExpr:
	return ((SC)this)->visitMulExpr((SCEVMulExpr)S);
	case scUDivExpr:
	return ((SC)this)->visitUDivExpr((SCEVUDivExpr)S);
	case scAddRecExpr:
	return ((SC)this)->visitAddRecExpr((SCEVAddRecExpr)S);
	case scSMaxExpr:
	return ((SC)this)->visitSMaxExpr((SCEVSMaxExpr)S);
	case scUMaxExpr:
	return ((SC)this)->visitUMaxExpr((SCEVUMaxExpr)S);
	case scUnknown:
	return ((SC)this)->visitUnknown((SCEVUnknown)S);
	case scCouldNotCompute:
	return ((SC)this)->visitCouldNotCompute((SCEVCouldNotCompute)S);
	default:
	assert(0 && "Unknown SCEV type!");
	abort();
	}
	}

	RetVal visitCouldNotCompute(SCEVCouldNotCompute *S) {
	assert(0 && "Invalid use of SCEVCouldNotCompute!");
	abort();
	return RetVal();
	}
	};
	}

	#endif