lib/Transforms/Vectorize/VPRecipeBuilder.h

   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/IR/IRBuilder.h"
  16
  17 namespace llvm {
  18
  19 class LoopVectorizationLegality;
  20 class LoopVectorizationCostModel;
  21 class TargetTransformInfo;
  22 class TargetLibraryInfo;
  23
  24 /// Helper class to create VPRecipies from IR instructions.
  25 class VPRecipeBuilder {
  26   /// The loop that we evaluate.
  27   Loop *OrigLoop;
  28
  29   /// Target Library Info.
  30   const TargetLibraryInfo *TLI;
  31
  32   /// The legality analysis.
  33   LoopVectorizationLegality *Legal;
  34
  35   /// The profitablity analysis.
  36   LoopVectorizationCostModel &CM;
  37
  38   VPBuilder &Builder;
  39
  40   /// When we if-convert we need to create edge masks. We have to cache values
  41   /// so that we don't end up with exponential recursion/IR. Note that
  42   /// if-conversion currently takes place during VPlan-construction, so these
  43   /// caches are only used at that stage.
  44   using EdgeMaskCacheTy =
  45       DenseMap<std::pair<BasicBlock *, BasicBlock *>, VPValue *>;
  46   using BlockMaskCacheTy = DenseMap<BasicBlock *, VPValue *>;
  47   EdgeMaskCacheTy EdgeMaskCache;
  48   BlockMaskCacheTy BlockMaskCache;
  49
  50 public:
  51   /// A helper function that computes the predicate of the block BB, assuming
  52   /// that the header block of the loop is set to True. It returns the *entry*
  53   /// mask for the block BB.
  54   VPValue *createBlockInMask(BasicBlock *BB, VPlanPtr &Plan);
  55
  56   /// A helper function that computes the predicate of the edge between SRC
  57   /// and DST.
  58   VPValue *createEdgeMask(BasicBlock *Src, BasicBlock *Dst, VPlanPtr &Plan);
  59
  60   /// Check if \I belongs to an Interleave Group within the given VF \p Range,
  61   /// \return true in the first returned value if so and false otherwise.
  62   /// Build a new VPInterleaveGroup Recipe if \I is the primary member of an IG
  63   /// for \p Range.Start, and provide it as the second returned value.
  64   /// Note that if \I is an adjunct member of an IG for \p Range.Start, the
  65   /// \return value is <true, nullptr>, as it is handled by another recipe.
  66   /// \p Range.End may be decreased to ensure same decision from \p Range.Start
  67   /// to \p Range.End.
  68   VPInterleaveRecipe *tryToInterleaveMemory(Instruction *I, VFRange &Range,
  69                                             VPlanPtr &Plan);
  70
  71   /// Check if \I is a memory instruction to be widened for \p Range.Start and
  72   /// potentially masked. Such instructions are handled by a recipe that takes
  73   /// an additional VPInstruction for the mask.
  74   VPWidenMemoryInstructionRecipe *
  75   tryToWidenMemory(Instruction *I, VFRange &Range, VPlanPtr &Plan);
  76
  77   /// Check if an induction recipe should be constructed for \I within the given
  78   /// VF \p Range. If so build and return it. If not, return null. \p Range.End
  79   /// may be decreased to ensure same decision from \p Range.Start to
  80   /// \p Range.End.
  81   VPWidenIntOrFpInductionRecipe *tryToOptimizeInduction(Instruction *I,
  82                                                         VFRange &Range);
  83
  84   /// Handle non-loop phi nodes. Currently all such phi nodes are turned into
  85   /// a sequence of select instructions as the vectorizer currently performs
  86   /// full if-conversion.
  87   VPBlendRecipe *tryToBlend(Instruction *I, VPlanPtr &Plan);
  88
  89   /// Check if \p I can be widened within the given VF \p Range. If \p I can be
  90   /// widened for \p Range.Start, check if the last recipe of \p VPBB can be
  91   /// extended to include \p I or else build a new VPWidenRecipe for it and
  92   /// append it to \p VPBB. Return true if \p I can be widened for Range.Start,
  93   /// false otherwise. Range.End may be decreased to ensure same decision from
  94   /// \p Range.Start to \p Range.End.
  95   bool tryToWiden(Instruction *I, VPBasicBlock *VPBB, VFRange &Range);
  96
  97   /// Create a replicating region for instruction \p I that requires
  98   /// predication. \p PredRecipe is a VPReplicateRecipe holding \p I.
  99   VPRegionBlock *createReplicateRegion(Instruction *I, VPRecipeBase *PredRecipe,
 100                                        VPlanPtr &Plan);
 101
 102 public:
 103   VPRecipeBuilder(Loop *OrigLoop, const TargetLibraryInfo *TLI,
 104                   LoopVectorizationLegality *Legal,
 105                   LoopVectorizationCostModel &CM, VPBuilder &Builder)
 106       : OrigLoop(OrigLoop), TLI(TLI), Legal(Legal), CM(CM), Builder(Builder) {}
 107
 108   /// Check if a recipe can be create for \p I withing the given VF \p Range.
 109   /// If a recipe can be created, it adds it to \p VPBB.
 110   bool tryToCreateRecipe(Instruction *Instr, VFRange &Range, VPlanPtr &Plan,
 111                          VPBasicBlock *VPBB);
 112
 113   /// Build a VPReplicationRecipe for \p I and enclose it within a Region if it
 114   /// is predicated. \return \p VPBB augmented with this new recipe if \p I is
 115   /// not predicated, otherwise \return a new VPBasicBlock that succeeds the new
 116   /// Region. Update the packing decision of predicated instructions if they
 117   /// feed \p I. Range.End may be decreased to ensure same recipe behavior from
 118   /// \p Range.Start to \p Range.End.
 119   VPBasicBlock *handleReplication(
 120       Instruction *I, VFRange &Range, VPBasicBlock *VPBB,
 121       DenseMap<Instruction *, VPReplicateRecipe *> &PredInst2Recipe,
 122       VPlanPtr &Plan);
 123 };
 124 } // end namespace llvm
 125
 126 #endif // LLVM_TRANSFORMS_VECTORIZE_VPRECIPEBUILDER_H