1 //===- VPRecipeBuilder.h - Helper class to build recipes --------*- 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 #ifndef LLVM_TRANSFORMS_VECTORIZE_VPRECIPEBUILDER_H 10 #define LLVM_TRANSFORMS_VECTORIZE_VPRECIPEBUILDER_H 11 12 #include "LoopVectorizationPlanner.h" 13 #include "VPlan.h" 14 #include "llvm/ADT/DenseMap.h" 15 #include "llvm/ADT/PointerUnion.h" 16 #include "llvm/IR/IRBuilder.h" 17 18 namespace llvm { 19 20 class LoopVectorizationLegality; 21 class LoopVectorizationCostModel; 22 class TargetLibraryInfo; 23 24 using VPRecipeOrVPValueTy = PointerUnion<VPRecipeBase *, VPValue *>; 25 26 /// Helper class to create VPRecipies from IR instructions. 27 class VPRecipeBuilder { 28 /// The loop that we evaluate. 29 Loop *OrigLoop; 30 31 /// Target Library Info. 32 const TargetLibraryInfo *TLI; 33 34 /// The legality analysis. 35 LoopVectorizationLegality *Legal; 36 37 /// The profitablity analysis. 38 LoopVectorizationCostModel &CM; 39 40 PredicatedScalarEvolution &PSE; 41 42 VPBuilder &Builder; 43 44 /// When we if-convert we need to create edge masks. We have to cache values 45 /// so that we don't end up with exponential recursion/IR. Note that 46 /// if-conversion currently takes place during VPlan-construction, so these 47 /// caches are only used at that stage. 48 using EdgeMaskCacheTy = 49 DenseMap<std::pair<BasicBlock *, BasicBlock *>, VPValue *>; 50 using BlockMaskCacheTy = DenseMap<BasicBlock *, VPValue *>; 51 EdgeMaskCacheTy EdgeMaskCache; 52 BlockMaskCacheTy BlockMaskCache; 53 54 // VPlan-VPlan transformations support: Hold a mapping from ingredients to 55 // their recipe. To save on memory, only do so for selected ingredients, 56 // marked by having a nullptr entry in this map. 57 DenseMap<Instruction *, VPRecipeBase *> Ingredient2Recipe; 58 59 /// Cross-iteration reduction & first-order recurrence phis for which we need 60 /// to add the incoming value from the backedge after all recipes have been 61 /// created. 62 SmallVector<VPHeaderPHIRecipe *, 4> PhisToFix; 63 64 /// Check if \p I can be widened at the start of \p Range and possibly 65 /// decrease the range such that the returned value holds for the entire \p 66 /// Range. The function should not be called for memory instructions or calls. 67 bool shouldWiden(Instruction *I, VFRange &Range) const; 68 69 /// Check if the load or store instruction \p I should widened for \p 70 /// Range.Start and potentially masked. Such instructions are handled by a 71 /// recipe that takes an additional VPInstruction for the mask. 72 VPRecipeBase *tryToWidenMemory(Instruction *I, ArrayRef<VPValue *> Operands, 73 VFRange &Range, VPlanPtr &Plan); 74 75 /// Check if an induction recipe should be constructed for \I. If so build and 76 /// return it. If not, return null. 77 VPWidenIntOrFpInductionRecipe * 78 tryToOptimizeInductionPHI(PHINode *Phi, ArrayRef<VPValue *> Operands, 79 VFRange &Range) const; 80 81 /// Optimize the special case where the operand of \p I is a constant integer 82 /// induction variable. 83 VPWidenIntOrFpInductionRecipe * 84 tryToOptimizeInductionTruncate(TruncInst *I, ArrayRef<VPValue *> Operands, 85 VFRange &Range, VPlan &Plan) const; 86 87 /// Handle non-loop phi nodes. Return a VPValue, if all incoming values match 88 /// or a new VPBlendRecipe otherwise. Currently all such phi nodes are turned 89 /// into a sequence of select instructions as the vectorizer currently 90 /// performs full if-conversion. 91 VPRecipeOrVPValueTy tryToBlend(PHINode *Phi, ArrayRef<VPValue *> Operands, 92 VPlanPtr &Plan); 93 94 /// Handle call instructions. If \p CI can be widened for \p Range.Start, 95 /// return a new VPWidenCallRecipe. Range.End may be decreased to ensure same 96 /// decision from \p Range.Start to \p Range.End. 97 VPWidenCallRecipe *tryToWidenCall(CallInst *CI, ArrayRef<VPValue *> Operands, 98 VFRange &Range) const; 99 100 /// Check if \p I has an opcode that can be widened and return a VPWidenRecipe 101 /// if it can. The function should only be called if the cost-model indicates 102 /// that widening should be performed. 103 VPWidenRecipe *tryToWiden(Instruction *I, ArrayRef<VPValue *> Operands) const; 104 105 /// Return a VPRecipeOrValueTy with VPRecipeBase * being set. This can be used to force the use as VPRecipeBase* for recipe sub-types that also inherit from VPValue. 106 VPRecipeOrVPValueTy toVPRecipeResult(VPRecipeBase *R) const { return R; } 107 108 public: 109 VPRecipeBuilder(Loop *OrigLoop, const TargetLibraryInfo *TLI, 110 LoopVectorizationLegality *Legal, 111 LoopVectorizationCostModel &CM, 112 PredicatedScalarEvolution &PSE, VPBuilder &Builder) 113 : OrigLoop(OrigLoop), TLI(TLI), Legal(Legal), CM(CM), PSE(PSE), 114 Builder(Builder) {} 115 116 /// Check if an existing VPValue can be used for \p Instr or a recipe can be 117 /// create for \p I withing the given VF \p Range. If an existing VPValue can 118 /// be used or if a recipe can be created, return it. Otherwise return a 119 /// VPRecipeOrVPValueTy with nullptr. 120 VPRecipeOrVPValueTy tryToCreateWidenRecipe(Instruction *Instr, 121 ArrayRef<VPValue *> Operands, 122 VFRange &Range, VPlanPtr &Plan); 123 124 /// Set the recipe created for given ingredient. This operation is a no-op for 125 /// ingredients that were not marked using a nullptr entry in the map. 126 void setRecipe(Instruction *I, VPRecipeBase *R) { 127 if (!Ingredient2Recipe.count(I)) 128 return; 129 assert(Ingredient2Recipe[I] == nullptr && 130 "Recipe already set for ingredient"); 131 Ingredient2Recipe[I] = R; 132 } 133 134 /// A helper function that computes the predicate of the block BB, assuming 135 /// that the header block of the loop is set to True. It returns the *entry* 136 /// mask for the block BB. 137 VPValue *createBlockInMask(BasicBlock *BB, VPlanPtr &Plan); 138 139 /// A helper function that computes the predicate of the edge between SRC 140 /// and DST. 141 VPValue *createEdgeMask(BasicBlock *Src, BasicBlock *Dst, VPlanPtr &Plan); 142 143 /// Mark given ingredient for recording its recipe once one is created for 144 /// it. 145 void recordRecipeOf(Instruction *I) { 146 assert((!Ingredient2Recipe.count(I) || Ingredient2Recipe[I] == nullptr) && 147 "Recipe already set for ingredient"); 148 Ingredient2Recipe[I] = nullptr; 149 } 150 151 /// Return the recipe created for given ingredient. 152 VPRecipeBase *getRecipe(Instruction *I) { 153 assert(Ingredient2Recipe.count(I) && 154 "Recording this ingredients recipe was not requested"); 155 assert(Ingredient2Recipe[I] != nullptr && 156 "Ingredient doesn't have a recipe"); 157 return Ingredient2Recipe[I]; 158 } 159 160 /// Create a replicating region for instruction \p I that requires 161 /// predication. \p PredRecipe is a VPReplicateRecipe holding \p I. 162 VPRegionBlock *createReplicateRegion(Instruction *I, VPRecipeBase *PredRecipe, 163 VPlanPtr &Plan); 164 165 /// Build a VPReplicationRecipe for \p I and enclose it within a Region if it 166 /// is predicated. \return \p VPBB augmented with this new recipe if \p I is 167 /// not predicated, otherwise \return a new VPBasicBlock that succeeds the new 168 /// Region. Update the packing decision of predicated instructions if they 169 /// feed \p I. Range.End may be decreased to ensure same recipe behavior from 170 /// \p Range.Start to \p Range.End. 171 VPBasicBlock *handleReplication( 172 Instruction *I, VFRange &Range, VPBasicBlock *VPBB, 173 VPlanPtr &Plan); 174 175 /// Add the incoming values from the backedge to reduction & first-order 176 /// recurrence cross-iteration phis. 177 void fixHeaderPhis(); 178 }; 179 } // end namespace llvm 180 181 #endif // LLVM_TRANSFORMS_VECTORIZE_VPRECIPEBUILDER_H 182