| 1 | //===-- llvm/Transforms/Utils/SimplifyIndVar.h - Indvar Utils ---*- C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This file defines in interface for induction variable simplification. It does |
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| 10 | // not define any actual pass or policy, but provides a single function to |
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| 11 | // simplify a loop's induction variables based on ScalarEvolution. |
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| 12 | // |
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| 13 | //===----------------------------------------------------------------------===// |
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| 14 | |
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| 15 | #ifndef LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H |
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| 16 | #define LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H |
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| 17 | |
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| 18 | namespace llvm { |
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| 19 | |
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| 20 | class Type; |
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| 21 | class WeakTrackingVH; |
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| 22 | template <typename T> class SmallVectorImpl; |
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| 23 | class CastInst; |
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| 24 | class DominatorTree; |
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| 25 | class Loop; |
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| 26 | class LoopInfo; |
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| 27 | class PHINode; |
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| 28 | class ScalarEvolution; |
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| 29 | class SCEVExpander; |
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| 30 | class TargetTransformInfo; |
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| 31 | |
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| 32 | /// Interface for visiting interesting IV users that are recognized but not |
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| 33 | /// simplified by this utility. |
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| 34 | class IVVisitor { |
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| 35 | protected: |
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| 36 | const DominatorTree *DT = nullptr; |
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| 37 | |
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| 38 | virtual void anchor(); |
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| 39 | |
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| 40 | public: |
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| 41 | IVVisitor() = default; |
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| 42 | virtual ~IVVisitor() = default; |
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| 43 | |
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| 44 | const DominatorTree *getDomTree() const { return DT; } |
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| 45 | virtual void visitCast(CastInst *Cast) = 0; |
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| 46 | }; |
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| 47 | |
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| 48 | /// simplifyUsersOfIV - Simplify instructions that use this induction variable |
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| 49 | /// by using ScalarEvolution to analyze the IV's recurrence. |
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| 50 | bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT, |
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| 51 | LoopInfo *LI, const TargetTransformInfo *TTI, |
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| 52 | SmallVectorImpl<WeakTrackingVH> &Dead, |
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| 53 | SCEVExpander &Rewriter, IVVisitor *V = nullptr); |
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| 54 | |
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| 55 | /// SimplifyLoopIVs - Simplify users of induction variables within this |
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| 56 | /// loop. This does not actually change or add IVs. |
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| 57 | bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, DominatorTree *DT, |
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| 58 | LoopInfo *LI, const TargetTransformInfo *TTI, |
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| 59 | SmallVectorImpl<WeakTrackingVH> &Dead); |
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| 60 | |
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| 61 | /// Collect information about induction variables that are used by sign/zero |
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| 62 | /// extend operations. This information is recorded by CollectExtend and provides |
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| 63 | /// the input to WidenIV. |
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| 64 | struct WideIVInfo { |
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| 65 | PHINode *NarrowIV = nullptr; |
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| 66 | |
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| 67 | // Widest integer type created [sz]ext |
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| 68 | Type *WidestNativeType = nullptr; |
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| 69 | |
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| 70 | // Was a sext user seen before a zext? |
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| 71 | bool IsSigned = false; |
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| 72 | }; |
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| 73 | |
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| 74 | /// Widen Induction Variables - Extend the width of an IV to cover its |
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| 75 | /// widest uses. |
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| 76 | PHINode *createWideIV(const WideIVInfo &WI, |
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| 77 | LoopInfo *LI, ScalarEvolution *SE, SCEVExpander &Rewriter, |
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| 78 | DominatorTree *DT, SmallVectorImpl<WeakTrackingVH> &DeadInsts, |
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| 79 | unsigned &NumElimExt, unsigned &NumWidened, |
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| 80 | bool HasGuards, bool UsePostIncrementRanges); |
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| 81 | |
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| 82 | } // end namespace llvm |
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| 83 | |
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| 84 | #endif // LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H |
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| 85 | |
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