1 //===- SLPVectorizer.h ------------------------------------------*- 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 // This pass implements the Bottom Up SLP vectorizer. It detects consecutive 9 // stores that can be put together into vector-stores. Next, it attempts to 10 // construct vectorizable tree using the use-def chains. If a profitable tree 11 // was found, the SLP vectorizer performs vectorization on the tree. 12 // 13 // The pass is inspired by the work described in the paper: 14 // "Loop-Aware SLP in GCC" by Ira Rosen, Dorit Nuzman, Ayal Zaks. 15 // 16 //===----------------------------------------------------------------------===// 17 18 #ifndef LLVM_TRANSFORMS_VECTORIZE_SLPVECTORIZER_H 19 #define LLVM_TRANSFORMS_VECTORIZE_SLPVECTORIZER_H 20 21 #include "llvm/ADT/ArrayRef.h" 22 #include "llvm/ADT/MapVector.h" 23 #include "llvm/ADT/None.h" 24 #include "llvm/ADT/SmallVector.h" 25 #include "llvm/Analysis/AliasAnalysis.h" 26 #include "llvm/IR/PassManager.h" 27 #include "llvm/Support/CommandLine.h" 28 29 namespace llvm { 30 31 class AssumptionCache; 32 class BasicBlock; 33 class CmpInst; 34 class DataLayout; 35 class DemandedBits; 36 class DominatorTree; 37 class Function; 38 class InsertElementInst; 39 class InsertValueInst; 40 class Instruction; 41 class LoopInfo; 42 class OptimizationRemarkEmitter; 43 class PHINode; 44 class ScalarEvolution; 45 class StoreInst; 46 class TargetLibraryInfo; 47 class TargetTransformInfo; 48 class Value; 49 50 /// A private "module" namespace for types and utilities used by this pass. 51 /// These are implementation details and should not be used by clients. 52 namespace slpvectorizer { 53 54 class BoUpSLP; 55 56 } // end namespace slpvectorizer 57 58 extern cl::opt<bool> RunSLPVectorization; 59 60 struct SLPVectorizerPass : public PassInfoMixin<SLPVectorizerPass> { 61 using StoreList = SmallVector<StoreInst *, 8>; 62 using StoreListMap = MapVector<Value *, StoreList>; 63 using GEPList = SmallVector<GetElementPtrInst *, 8>; 64 using GEPListMap = MapVector<Value *, GEPList>; 65 66 ScalarEvolution *SE = nullptr; 67 TargetTransformInfo *TTI = nullptr; 68 TargetLibraryInfo *TLI = nullptr; 69 AliasAnalysis *AA = nullptr; 70 LoopInfo *LI = nullptr; 71 DominatorTree *DT = nullptr; 72 AssumptionCache *AC = nullptr; 73 DemandedBits *DB = nullptr; 74 const DataLayout *DL = nullptr; 75 76 public: 77 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); 78 79 // Glue for old PM. 80 bool runImpl(Function &F, ScalarEvolution *SE_, TargetTransformInfo *TTI_, 81 TargetLibraryInfo *TLI_, AliasAnalysis *AA_, LoopInfo *LI_, 82 DominatorTree *DT_, AssumptionCache *AC_, DemandedBits *DB_, 83 OptimizationRemarkEmitter *ORE_); 84 85 private: 86 /// Collect store and getelementptr instructions and organize them 87 /// according to the underlying object of their pointer operands. We sort the 88 /// instructions by their underlying objects to reduce the cost of 89 /// consecutive access queries. 90 /// 91 /// TODO: We can further reduce this cost if we flush the chain creation 92 /// every time we run into a memory barrier. 93 void collectSeedInstructions(BasicBlock *BB); 94 95 /// Try to vectorize a chain that starts at two arithmetic instrs. 96 bool tryToVectorizePair(Value *A, Value *B, slpvectorizer::BoUpSLP &R); 97 98 /// Try to vectorize a list of operands. 99 /// \param UserCost Cost of the user operations of \p VL if they may affect 100 /// the cost of the vectorization. 101 /// \returns true if a value was vectorized. 102 bool tryToVectorizeList(ArrayRef<Value *> VL, slpvectorizer::BoUpSLP &R, 103 int UserCost = 0, bool AllowReorder = false); 104 105 /// Try to vectorize a chain that may start at the operands of \p I. 106 bool tryToVectorize(Instruction *I, slpvectorizer::BoUpSLP &R); 107 108 /// Vectorize the store instructions collected in Stores. 109 bool vectorizeStoreChains(slpvectorizer::BoUpSLP &R); 110 111 /// Vectorize the index computations of the getelementptr instructions 112 /// collected in GEPs. 113 bool vectorizeGEPIndices(BasicBlock *BB, slpvectorizer::BoUpSLP &R); 114 115 /// Try to find horizontal reduction or otherwise vectorize a chain of binary 116 /// operators. 117 bool vectorizeRootInstruction(PHINode *P, Value *V, BasicBlock *BB, 118 slpvectorizer::BoUpSLP &R, 119 TargetTransformInfo *TTI); 120 121 /// Try to vectorize trees that start at insertvalue instructions. 122 bool vectorizeInsertValueInst(InsertValueInst *IVI, BasicBlock *BB, 123 slpvectorizer::BoUpSLP &R); 124 125 /// Try to vectorize trees that start at insertelement instructions. 126 bool vectorizeInsertElementInst(InsertElementInst *IEI, BasicBlock *BB, 127 slpvectorizer::BoUpSLP &R); 128 129 /// Try to vectorize trees that start at compare instructions. 130 bool vectorizeCmpInst(CmpInst *CI, BasicBlock *BB, slpvectorizer::BoUpSLP &R); 131 132 /// Tries to vectorize constructs started from CmpInst, InsertValueInst or 133 /// InsertElementInst instructions. 134 bool vectorizeSimpleInstructions(SmallVectorImpl<Instruction *> &Instructions, 135 BasicBlock *BB, slpvectorizer::BoUpSLP &R); 136 137 /// Scan the basic block and look for patterns that are likely to start 138 /// a vectorization chain. 139 bool vectorizeChainsInBlock(BasicBlock *BB, slpvectorizer::BoUpSLP &R); 140 141 bool vectorizeStoreChain(ArrayRef<Value *> Chain, slpvectorizer::BoUpSLP &R, 142 unsigned Idx); 143 144 bool vectorizeStores(ArrayRef<StoreInst *> Stores, slpvectorizer::BoUpSLP &R); 145 146 /// The store instructions in a basic block organized by base pointer. 147 StoreListMap Stores; 148 149 /// The getelementptr instructions in a basic block organized by base pointer. 150 GEPListMap GEPs; 151 }; 152 153 } // end namespace llvm 154 155 #endif // LLVM_TRANSFORMS_VECTORIZE_SLPVECTORIZER_H 156