1 //===-- llvm/Transforms/Utils/SimplifyIndVar.h - Indvar Utils ---*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines in interface for induction variable simplification. It does
10 // not define any actual pass or policy, but provides a single function to
11 // simplify a loop's induction variables based on ScalarEvolution.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
16 #define LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
17 
18 #include "llvm/IR/ValueHandle.h"
19 
20 namespace llvm {
21 
22 class CastInst;
23 class DominatorTree;
24 class Loop;
25 class LoopInfo;
26 class PHINode;
27 class ScalarEvolution;
28 class SCEVExpander;
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<WeakTrackingVH> &Dead,
50                        SCEVExpander &Rewriter, 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<WeakTrackingVH> &Dead);
56 
57 } // end namespace llvm
58 
59 #endif // LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
60