--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/llvm/Analysis/ScalarEvolutionExpressions.h	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,752 @@
+//===- 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_SCALAREVOLUTIONEXPRESSIONS_H
+#define LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H
+
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Support/ErrorHandling.h"
+
+namespace llvm {
+  class ConstantInt;
+  class ConstantRange;
+  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
+  };
+
+  //===--------------------------------------------------------------------===//
+  /// SCEVConstant - This class represents a constant integer value.
+  ///
+  class SCEVConstant : public SCEV {
+    friend class ScalarEvolution;
+
+    ConstantInt *V;
+    SCEVConstant(const FoldingSetNodeIDRef ID, ConstantInt *v) :
+      SCEV(ID, scConstant), V(v) {}
+  public:
+    ConstantInt *getValue() const { return V; }
+
+    Type *getType() const { return V->getType(); }
+
+    /// Methods for support type inquiry through isa, cast, and dyn_cast:
+    static inline bool classof(const SCEV *S) {
+      return S->getSCEVType() == scConstant;
+    }
+  };
+
+  //===--------------------------------------------------------------------===//
+  /// SCEVCastExpr - This is the base class for unary cast operator classes.
+  ///
+  class SCEVCastExpr : public SCEV {
+  protected:
+    const SCEV *Op;
+    Type *Ty;
+
+    SCEVCastExpr(const FoldingSetNodeIDRef ID,
+                 unsigned SCEVTy, const SCEV *op, Type *ty);
+
+  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 SCEV *S) {
+      return S->getSCEVType() == scTruncate ||
+             S->getSCEVType() == scZeroExtend ||
+             S->getSCEVType() == scSignExtend;
+    }
+  };
+
+  //===--------------------------------------------------------------------===//
+  /// SCEVTruncateExpr - This class represents a truncation of an integer value
+  /// to a smaller integer value.
+  ///
+  class SCEVTruncateExpr : public SCEVCastExpr {
+    friend class ScalarEvolution;
+
+    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 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 SCEVCastExpr {
+    friend class ScalarEvolution;
+
+    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 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 SCEVCastExpr {
+    friend class ScalarEvolution;
+
+    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 SCEV *S) {
+      return S->getSCEVType() == scSignExtend;
+    }
+  };
+
+
+  //===--------------------------------------------------------------------===//
+  /// SCEVNAryExpr - This node is a base class providing common
+  /// functionality for n'ary operators.
+  ///
+  class SCEVNAryExpr : public SCEV {
+  protected:
+    // 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:
+    size_t getNumOperands() const { return NumOperands; }
+    const SCEV *getOperand(unsigned i) const {
+      assert(i < NumOperands && "Operand index out of range!");
+      return Operands[i];
+    }
+
+    typedef const SCEV *const *op_iterator;
+    op_iterator op_begin() const { return Operands; }
+    op_iterator op_end() const { return Operands + NumOperands; }
+
+    Type *getType() const { return getOperand(0)->getType(); }
+
+    NoWrapFlags getNoWrapFlags(NoWrapFlags Mask = NoWrapMask) const {
+      return (NoWrapFlags)(SubclassData & Mask);
+    }
+
+    /// 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;
+    }
+  };
+
+  //===--------------------------------------------------------------------===//
+  /// 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 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;
+    }
+  };
+
+
+  //===--------------------------------------------------------------------===//
+  /// SCEVAddExpr - This node represents an addition of some number of SCEVs.
+  ///
+  class SCEVAddExpr : public SCEVCommutativeExpr {
+    friend class ScalarEvolution;
+
+    SCEVAddExpr(const FoldingSetNodeIDRef ID,
+                const SCEV *const *O, size_t N)
+      : SCEVCommutativeExpr(ID, scAddExpr, O, N) {
+    }
+
+  public:
+    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 SCEV *S) {
+      return S->getSCEVType() == scAddExpr;
+    }
+  };
+
+  //===--------------------------------------------------------------------===//
+  /// SCEVMulExpr - This node represents multiplication of some number of SCEVs.
+  ///
+  class SCEVMulExpr : public SCEVCommutativeExpr {
+    friend class ScalarEvolution;
+
+    SCEVMulExpr(const FoldingSetNodeIDRef ID,
+                const SCEV *const *O, size_t N)
+      : SCEVCommutativeExpr(ID, scMulExpr, O, N) {
+    }
+
+  public:
+    /// Methods for support type inquiry through isa, cast, and dyn_cast:
+    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;
+
+    const SCEV *LHS;
+    const SCEV *RHS;
+    SCEVUDivExpr(const FoldingSetNodeIDRef ID, const SCEV *lhs, const SCEV *rhs)
+      : SCEV(ID, scUDivExpr), LHS(lhs), RHS(rhs) {}
+
+  public:
+    const SCEV *getLHS() const { return LHS; }
+    const SCEV *getRHS() const { return RHS; }
+
+    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();
+    }
+
+    /// Methods for support type inquiry through isa, cast, and dyn_cast:
+    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.  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 SCEVNAryExpr {
+    friend class ScalarEvolution;
+
+    const Loop *L;
+
+    SCEVAddRecExpr(const FoldingSetNodeIDRef ID,
+                   const SCEV *const *O, size_t N, const Loop *l)
+      : SCEVNAryExpr(ID, scAddRecExpr, O, N), L(l) {}
+
+  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.
+    /// We cannot determine whether the step recurrence has self-wraparound.
+    const SCEV *getStepRecurrence(ScalarEvolution &SE) const {
+      if (isAffine()) return getOperand(1);
+      return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1,
+                                                           op_end()),
+                              getLoop(), FlagAnyWrap);
+    }
+
+    /// 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;
+    }
+
+    /// 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.
+    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
+    /// 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.
+    const SCEV *getNumIterationsInRange(ConstantRange Range,
+                                       ScalarEvolution &SE) 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<SCEVAddRecExpr>(SE.getAddExpr(this, getStepRecurrence(SE)));
+    }
+
+    /// Methods for support type inquiry through isa, cast, and dyn_cast:
+    static inline bool classof(const SCEV *S) {
+      return S->getSCEVType() == scAddRecExpr;
+    }
+
+    /// Splits the SCEV into two vectors of SCEVs representing the subscripts
+    /// and sizes of an array access. Returns the remainder of the
+    /// delinearization that is the offset start of the array.
+    const SCEV *delinearize(ScalarEvolution &SE,
+                            SmallVectorImpl<const SCEV *> &Subscripts,
+                            SmallVectorImpl<const SCEV *> &Sizes) const;
+  };
+
+  //===--------------------------------------------------------------------===//
+  /// SCEVSMaxExpr - This class represents a signed maximum selection.
+  ///
+  class SCEVSMaxExpr : public SCEVCommutativeExpr {
+    friend class ScalarEvolution;
+
+    SCEVSMaxExpr(const FoldingSetNodeIDRef ID,
+                 const SCEV *const *O, size_t N)
+      : SCEVCommutativeExpr(ID, scSMaxExpr, O, N) {
+      // Max never overflows.
+      setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW));
+    }
+
+  public:
+    /// Methods for support type inquiry through isa, cast, and dyn_cast:
+    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;
+
+    SCEVUMaxExpr(const FoldingSetNodeIDRef ID,
+                 const SCEV *const *O, size_t N)
+      : SCEVCommutativeExpr(ID, scUMaxExpr, O, N) {
+      // Max never overflows.
+      setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW));
+    }
+
+  public:
+    /// Methods for support type inquiry through isa, cast, and dyn_cast:
+    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 its LLVM Value.  This is the "bottom"
+  /// value for the analysis.
+  ///
+  class SCEVUnknown : public SCEV, private CallbackVH {
+    friend class ScalarEvolution;
+
+    // Implement CallbackVH.
+    virtual void deleted();
+    virtual void allUsesReplacedWith(Value *New);
+
+    /// 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;
+
+    /// Next - The next pointer in the linked list of all
+    /// SCEVUnknown instances owned by a ScalarEvolution.
+    SCEVUnknown *Next;
+
+    SCEVUnknown(const FoldingSetNodeIDRef ID, Value *V,
+                ScalarEvolution *se, SCEVUnknown *next) :
+      SCEV(ID, scUnknown), CallbackVH(V), SE(se), Next(next) {}
+
+  public:
+    Value *getValue() const { return getValPtr(); }
+
+    /// 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;
+
+    Type *getType() const { return getValPtr()->getType(); }
+
+    /// Methods for support type inquiry through isa, cast, and dyn_cast:
+    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(const SCEV *S) {
+      switch (S->getSCEVType()) {
+      case scConstant:
+        return ((SC*)this)->visitConstant((const SCEVConstant*)S);
+      case scTruncate:
+        return ((SC*)this)->visitTruncateExpr((const SCEVTruncateExpr*)S);
+      case scZeroExtend:
+        return ((SC*)this)->visitZeroExtendExpr((const SCEVZeroExtendExpr*)S);
+      case scSignExtend:
+        return ((SC*)this)->visitSignExtendExpr((const SCEVSignExtendExpr*)S);
+      case scAddExpr:
+        return ((SC*)this)->visitAddExpr((const SCEVAddExpr*)S);
+      case scMulExpr:
+        return ((SC*)this)->visitMulExpr((const SCEVMulExpr*)S);
+      case scUDivExpr:
+        return ((SC*)this)->visitUDivExpr((const SCEVUDivExpr*)S);
+      case scAddRecExpr:
+        return ((SC*)this)->visitAddRecExpr((const SCEVAddRecExpr*)S);
+      case scSMaxExpr:
+        return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S);
+      case scUMaxExpr:
+        return ((SC*)this)->visitUMaxExpr((const SCEVUMaxExpr*)S);
+      case scUnknown:
+        return ((SC*)this)->visitUnknown((const SCEVUnknown*)S);
+      case scCouldNotCompute:
+        return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S);
+      default:
+        llvm_unreachable("Unknown SCEV type!");
+      }
+    }
+
+    RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) {
+      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<typename SV>
+  class SCEVTraversal {
+    SV &Visitor;
+    SmallVector<const SCEV *, 8> Worklist;
+    SmallPtrSet<const SCEV *, 8> Visited;
+
+    void push(const SCEV *S) {
+      if (Visited.insert(S) && 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<SCEVCastExpr>(S)->getOperand());
+          break;
+        case scAddExpr:
+        case scMulExpr:
+        case scSMaxExpr:
+        case scUMaxExpr:
+        case scAddRecExpr: {
+          const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(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<SCEVUDivExpr>(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 givien expression tree.
+  template<typename SV>
+  void visitAll(const SCEV *Root, SV& Visitor) {
+    SCEVTraversal<SV> T(Visitor);
+    T.visitAll(Root);
+  }
+
+  typedef DenseMap<const Value*, Value*> ValueToValueMap;
+
+  /// The SCEVParameterRewriter takes a scalar evolution expression and updates
+  /// the SCEVUnknown components following the Map (Value -> Value).
+  struct SCEVParameterRewriter
+    : public SCEVVisitor<SCEVParameterRewriter, const SCEV*> {
+  public:
+    static const SCEV *rewrite(const SCEV *Scev, ScalarEvolution &SE,
+                               ValueToValueMap &Map) {
+      SCEVParameterRewriter Rewriter(SE, Map);
+      return Rewriter.visit(Scev);
+    }
+
+    SCEVParameterRewriter(ScalarEvolution &S, ValueToValueMap &M)
+      : SE(S), Map(M) {}
+
+    const SCEV *visitConstant(const SCEVConstant *Constant) {
+      return Constant;
+    }
+
+    const SCEV *visitTruncateExpr(const SCEVTruncateExpr *Expr) {
+      const SCEV *Operand = visit(Expr->getOperand());
+      return SE.getTruncateExpr(Operand, Expr->getType());
+    }
+
+    const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) {
+      const SCEV *Operand = visit(Expr->getOperand());
+      return SE.getZeroExtendExpr(Operand, Expr->getType());
+    }
+
+    const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) {
+      const SCEV *Operand = visit(Expr->getOperand());
+      return SE.getSignExtendExpr(Operand, Expr->getType());
+    }
+
+    const SCEV *visitAddExpr(const SCEVAddExpr *Expr) {
+      SmallVector<const SCEV *, 2> Operands;
+      for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
+        Operands.push_back(visit(Expr->getOperand(i)));
+      return SE.getAddExpr(Operands);
+    }
+
+    const SCEV *visitMulExpr(const SCEVMulExpr *Expr) {
+      SmallVector<const SCEV *, 2> Operands;
+      for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
+        Operands.push_back(visit(Expr->getOperand(i)));
+      return SE.getMulExpr(Operands);
+    }
+
+    const SCEV *visitUDivExpr(const SCEVUDivExpr *Expr) {
+      return SE.getUDivExpr(visit(Expr->getLHS()), visit(Expr->getRHS()));
+    }
+
+    const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
+      SmallVector<const SCEV *, 2> Operands;
+      for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
+        Operands.push_back(visit(Expr->getOperand(i)));
+      return SE.getAddRecExpr(Operands, Expr->getLoop(),
+                              Expr->getNoWrapFlags());
+    }
+
+    const SCEV *visitSMaxExpr(const SCEVSMaxExpr *Expr) {
+      SmallVector<const SCEV *, 2> Operands;
+      for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
+        Operands.push_back(visit(Expr->getOperand(i)));
+      return SE.getSMaxExpr(Operands);
+    }
+
+    const SCEV *visitUMaxExpr(const SCEVUMaxExpr *Expr) {
+      SmallVector<const SCEV *, 2> Operands;
+      for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
+        Operands.push_back(visit(Expr->getOperand(i)));
+      return SE.getUMaxExpr(Operands);
+    }
+
+    const SCEV *visitUnknown(const SCEVUnknown *Expr) {
+      Value *V = Expr->getValue();
+      if (Map.count(V))
+        return SE.getUnknown(Map[V]);
+      return Expr;
+    }
+
+    const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) {
+      return Expr;
+    }
+
+  private:
+    ScalarEvolution &SE;
+    ValueToValueMap &Map;
+  };
+
+  typedef DenseMap<const Loop*, const SCEV*> LoopToScevMapT;
+
+  /// The SCEVApplyRewriter takes a scalar evolution expression and applies
+  /// the Map (Loop -> SCEV) to all AddRecExprs.
+  struct SCEVApplyRewriter
+    : public SCEVVisitor<SCEVApplyRewriter, const SCEV*> {
+  public:
+    static const SCEV *rewrite(const SCEV *Scev, LoopToScevMapT &Map,
+                               ScalarEvolution &SE) {
+      SCEVApplyRewriter Rewriter(SE, Map);
+      return Rewriter.visit(Scev);
+    }
+
+    SCEVApplyRewriter(ScalarEvolution &S, LoopToScevMapT &M)
+      : SE(S), Map(M) {}
+
+    const SCEV *visitConstant(const SCEVConstant *Constant) {
+      return Constant;
+    }
+
+    const SCEV *visitTruncateExpr(const SCEVTruncateExpr *Expr) {
+      const SCEV *Operand = visit(Expr->getOperand());
+      return SE.getTruncateExpr(Operand, Expr->getType());
+    }
+
+    const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) {
+      const SCEV *Operand = visit(Expr->getOperand());
+      return SE.getZeroExtendExpr(Operand, Expr->getType());
+    }
+
+    const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) {
+      const SCEV *Operand = visit(Expr->getOperand());
+      return SE.getSignExtendExpr(Operand, Expr->getType());
+    }
+
+    const SCEV *visitAddExpr(const SCEVAddExpr *Expr) {
+      SmallVector<const SCEV *, 2> Operands;
+      for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
+        Operands.push_back(visit(Expr->getOperand(i)));
+      return SE.getAddExpr(Operands);
+    }
+
+    const SCEV *visitMulExpr(const SCEVMulExpr *Expr) {
+      SmallVector<const SCEV *, 2> Operands;
+      for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
+        Operands.push_back(visit(Expr->getOperand(i)));
+      return SE.getMulExpr(Operands);
+    }
+
+    const SCEV *visitUDivExpr(const SCEVUDivExpr *Expr) {
+      return SE.getUDivExpr(visit(Expr->getLHS()), visit(Expr->getRHS()));
+    }
+
+    const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
+      SmallVector<const SCEV *, 2> 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 = (const SCEVAddRecExpr *) Res;
+      return Rec->evaluateAtIteration(Map[L], SE);
+    }
+
+    const SCEV *visitSMaxExpr(const SCEVSMaxExpr *Expr) {
+      SmallVector<const SCEV *, 2> Operands;
+      for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
+        Operands.push_back(visit(Expr->getOperand(i)));
+      return SE.getSMaxExpr(Operands);
+    }
+
+    const SCEV *visitUMaxExpr(const SCEVUMaxExpr *Expr) {
+      SmallVector<const SCEV *, 2> Operands;
+      for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
+        Operands.push_back(visit(Expr->getOperand(i)));
+      return SE.getUMaxExpr(Operands);
+    }
+
+    const SCEV *visitUnknown(const SCEVUnknown *Expr) {
+      return Expr;
+    }
+
+    const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) {
+      return Expr;
+    }
+
+  private:
+    ScalarEvolution &SE;
+    LoopToScevMapT &Map;
+  };
+
+/// Applies the Map (Loop -> SCEV) to the given Scev.
+static inline const SCEV *apply(const SCEV *Scev, LoopToScevMapT &Map,
+                                ScalarEvolution &SE) {
+  return SCEVApplyRewriter::rewrite(Scev, Map, SE);
+}
+
+}
+
+#endif