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      1 //===-- llvm/Transforms/Utils/SimplifyIndVar.h - Indvar Utils ---*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file defines in interface for induction variable simplification. It does
     11 // not define any actual pass or policy, but provides a single function to
     12 // simplify a loop's induction variables based on ScalarEvolution.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 #ifndef LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
     17 #define LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
     18 
     19 #include "llvm/IR/ValueHandle.h"
     20 
     21 namespace llvm {
     22 
     23 class CastInst;
     24 class DominatorTree;
     25 class Loop;
     26 class LoopInfo;
     27 class PHINode;
     28 class ScalarEvolution;
     29 
     30 /// Interface for visiting interesting IV users that are recognized but not
     31 /// simplified by this utility.
     32 class IVVisitor {
     33 protected:
     34   const DominatorTree *DT = nullptr;
     35 
     36   virtual void anchor();
     37 
     38 public:
     39   IVVisitor() = default;
     40   virtual ~IVVisitor() = default;
     41 
     42   const DominatorTree *getDomTree() const { return DT; }
     43   virtual void visitCast(CastInst *Cast) = 0;
     44 };
     45 
     46 /// simplifyUsersOfIV - Simplify instructions that use this induction variable
     47 /// by using ScalarEvolution to analyze the IV's recurrence.
     48 bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
     49                        LoopInfo *LI, SmallVectorImpl<WeakVH> &Dead,
     50                        IVVisitor *V = nullptr);
     51 
     52 /// SimplifyLoopIVs - Simplify users of induction variables within this
     53 /// loop. This does not actually change or add IVs.
     54 bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, DominatorTree *DT,
     55                      LoopInfo *LI, SmallVectorImpl<WeakVH> &Dead);
     56 
     57 } // end namespace llvm
     58 
     59 #endif // LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
     60