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 #include "llvm/Support/CommandLine.h"
21 
22 namespace llvm {
23 
24 class CastInst;
25 class DominatorTree;
26 class IVUsers;
27 class Loop;
28 class LoopInfo;
29 class PHINode;
30 class ScalarEvolution;
31 
32 /// Interface for visiting interesting IV users that are recognized but not
33 /// simplified by this utility.
34 class IVVisitor {
35 protected:
36   const DominatorTree *DT;
37   bool ShouldSplitOverflowIntrinsics;
38 
39   virtual void anchor();
40 
41 public:
IVVisitor()42   IVVisitor(): DT(nullptr), ShouldSplitOverflowIntrinsics(false) {}
~IVVisitor()43   virtual ~IVVisitor() {}
44 
getDomTree()45   const DominatorTree *getDomTree() const { return DT; }
46 
shouldSplitOverflowInstrinsics()47   bool shouldSplitOverflowInstrinsics() const {
48     return ShouldSplitOverflowIntrinsics;
49   }
setSplitOverflowIntrinsics()50   void setSplitOverflowIntrinsics() {
51     ShouldSplitOverflowIntrinsics = true;
52     assert(DT && "Splitting overflow intrinsics requires a DomTree.");
53   }
54 
55   virtual void visitCast(CastInst *Cast) = 0;
56 };
57 
58 /// simplifyUsersOfIV - Simplify instructions that use this induction variable
59 /// by using ScalarEvolution to analyze the IV's recurrence.
60 bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
61                        LoopInfo *LI, SmallVectorImpl<WeakVH> &Dead,
62                        IVVisitor *V = nullptr);
63 
64 /// SimplifyLoopIVs - Simplify users of induction variables within this
65 /// loop. This does not actually change or add IVs.
66 bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, DominatorTree *DT,
67                      LoopInfo *LI, SmallVectorImpl<WeakVH> &Dead);
68 
69 } // namespace llvm
70 
71 #endif
72