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 class TargetTransformInfo;
30 
31 /// Interface for visiting interesting IV users that are recognized but not
32 /// simplified by this utility.
33 class IVVisitor {
34 protected:
35   const DominatorTree *DT = nullptr;
36 
37   virtual void anchor();
38 
39 public:
40   IVVisitor() = default;
41   virtual ~IVVisitor() = default;
42 
43   const DominatorTree *getDomTree() const { return DT; }
44   virtual void visitCast(CastInst *Cast) = 0;
45 };
46 
47 /// simplifyUsersOfIV - Simplify instructions that use this induction variable
48 /// by using ScalarEvolution to analyze the IV's recurrence.
49 bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
50                        LoopInfo *LI, const TargetTransformInfo *TTI,
51                        SmallVectorImpl<WeakTrackingVH> &Dead,
52                        SCEVExpander &Rewriter, IVVisitor *V = nullptr);
53 
54 /// SimplifyLoopIVs - Simplify users of induction variables within this
55 /// loop. This does not actually change or add IVs.
56 bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, DominatorTree *DT,
57                      LoopInfo *LI, const TargetTransformInfo *TTI,
58                      SmallVectorImpl<WeakTrackingVH> &Dead);
59 
60 } // end namespace llvm
61 
62 #endif // LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
63