contrib/llvm/lib/Transforms/Vectorize/VPlanHCFGTransforms.cpp

   1 //===-- VPlanHCFGTransforms.cpp - Utility VPlan to VPlan transforms -------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 ///
  10 /// \file
  11 /// This file implements a set of utility VPlan to VPlan transformations.
  12 ///
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "VPlanHCFGTransforms.h"
  16 #include "llvm/ADT/PostOrderIterator.h"
  17
  18 using namespace llvm;
  19
  20 void VPlanHCFGTransforms::VPInstructionsToVPRecipes(
  21     VPlanPtr &Plan,
  22     LoopVectorizationLegality::InductionList *Inductions,
  23     SmallPtrSetImpl<Instruction *> &DeadInstructions) {
  24
  25   VPRegionBlock *TopRegion = dyn_cast<VPRegionBlock>(Plan->getEntry());
  26   ReversePostOrderTraversal<VPBlockBase *> RPOT(TopRegion->getEntry());
  27   for (VPBlockBase *Base : RPOT) {
  28     // Do not widen instructions in pre-header and exit blocks.
  29     if (Base->getNumPredecessors() == 0 || Base->getNumSuccessors() == 0)
  30       continue;
  31
  32     VPBasicBlock *VPBB = Base->getEntryBasicBlock();
  33     VPRecipeBase *LastRecipe = nullptr;
  34     // Introduce each ingredient into VPlan.
  35     for (auto I = VPBB->begin(), E = VPBB->end(); I != E;) {
  36       VPRecipeBase *Ingredient = &*I++;
  37       // Can only handle VPInstructions.
  38       VPInstruction *VPInst = cast<VPInstruction>(Ingredient);
  39       Instruction *Inst = cast<Instruction>(VPInst->getUnderlyingValue());
  40       if (DeadInstructions.count(Inst)) {
  41         Ingredient->eraseFromParent();
  42         continue;
  43       }
  44
  45       VPRecipeBase *NewRecipe = nullptr;
  46       // Create VPWidenMemoryInstructionRecipe for loads and stores.
  47       if (isa<LoadInst>(Inst) || isa<StoreInst>(Inst))
  48         NewRecipe = new VPWidenMemoryInstructionRecipe(*Inst, nullptr /*Mask*/);
  49       else if (PHINode *Phi = dyn_cast<PHINode>(Inst)) {
  50         InductionDescriptor II = Inductions->lookup(Phi);
  51         if (II.getKind() == InductionDescriptor::IK_IntInduction ||
  52             II.getKind() == InductionDescriptor::IK_FpInduction) {
  53           NewRecipe = new VPWidenIntOrFpInductionRecipe(Phi);
  54         } else
  55           NewRecipe = new VPWidenPHIRecipe(Phi);
  56       } else {
  57         // If the last recipe is a VPWidenRecipe, add Inst to it instead of
  58         // creating a new recipe.
  59         if (VPWidenRecipe *WidenRecipe =
  60                 dyn_cast_or_null<VPWidenRecipe>(LastRecipe)) {
  61           WidenRecipe->appendInstruction(Inst);
  62           Ingredient->eraseFromParent();
  63           continue;
  64         }
  65         NewRecipe = new VPWidenRecipe(Inst);
  66       }
  67
  68       NewRecipe->insertBefore(Ingredient);
  69       LastRecipe = NewRecipe;
  70       Ingredient->eraseFromParent();
  71     }
  72   }
  73 }