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 namespace llvm { 19 20 class Type; 21 class WeakTrackingVH; 22 template <typename T> class SmallVectorImpl; 23 class CastInst; 24 class DominatorTree; 25 class Loop; 26 class LoopInfo; 27 class PHINode; 28 class ScalarEvolution; 29 class SCEVExpander; 30 class TargetTransformInfo; 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 = nullptr; 37 38 virtual void anchor(); 39 40 public: 41 IVVisitor() = default; 42 virtual ~IVVisitor() = default; 43 44 const DominatorTree *getDomTree() const { return DT; } 45 virtual void visitCast(CastInst *Cast) = 0; 46 }; 47 48 /// simplifyUsersOfIV - Simplify instructions that use this induction variable 49 /// by using ScalarEvolution to analyze the IV's recurrence. 50 bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT, 51 LoopInfo *LI, const TargetTransformInfo *TTI, 52 SmallVectorImpl<WeakTrackingVH> &Dead, 53 SCEVExpander &Rewriter, IVVisitor *V = nullptr); 54 55 /// SimplifyLoopIVs - Simplify users of induction variables within this 56 /// loop. This does not actually change or add IVs. 57 bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, DominatorTree *DT, 58 LoopInfo *LI, const TargetTransformInfo *TTI, 59 SmallVectorImpl<WeakTrackingVH> &Dead); 60 61 /// Collect information about induction variables that are used by sign/zero 62 /// extend operations. This information is recorded by CollectExtend and provides 63 /// the input to WidenIV. 64 struct WideIVInfo { 65 PHINode *NarrowIV = nullptr; 66 67 // Widest integer type created [sz]ext 68 Type *WidestNativeType = nullptr; 69 70 // Was a sext user seen before a zext? 71 bool IsSigned = false; 72 }; 73 74 /// Widen Induction Variables - Extend the width of an IV to cover its 75 /// widest uses. 76 PHINode *createWideIV(const WideIVInfo &WI, 77 LoopInfo *LI, ScalarEvolution *SE, SCEVExpander &Rewriter, 78 DominatorTree *DT, SmallVectorImpl<WeakTrackingVH> &DeadInsts, 79 unsigned &NumElimExt, unsigned &NumWidened, 80 bool HasGuards, bool UsePostIncrementRanges); 81 82 } // end namespace llvm 83 84 #endif // LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H 85