1 //===- VPlanTransforms.h - Utility VPlan to VPlan transforms --------------===// 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 /// \file 10 /// This file provides utility VPlan to VPlan transformations. 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_TRANSFORMS_VECTORIZE_VPLANTRANSFORMS_H 14 #define LLVM_TRANSFORMS_VECTORIZE_VPLANTRANSFORMS_H 15 16 #include "VPlan.h" 17 #include "llvm/ADT/STLFunctionalExtras.h" 18 19 namespace llvm { 20 21 class InductionDescriptor; 22 class Instruction; 23 class PHINode; 24 class ScalarEvolution; 25 class Loop; 26 class PredicatedScalarEvolution; 27 class TargetLibraryInfo; 28 class VPBuilder; 29 class VPRecipeBuilder; 30 31 struct VPlanTransforms { 32 /// Replaces the VPInstructions in \p Plan with corresponding 33 /// widen recipes. 34 static void 35 VPInstructionsToVPRecipes(VPlanPtr &Plan, 36 function_ref<const InductionDescriptor *(PHINode *)> 37 GetIntOrFpInductionDescriptor, 38 ScalarEvolution &SE, const TargetLibraryInfo &TLI); 39 40 /// Wrap predicated VPReplicateRecipes with a mask operand in an if-then 41 /// region block and remove the mask operand. Optimize the created regions by 42 /// iteratively sinking scalar operands into the region, followed by merging 43 /// regions until no improvements are remaining. 44 static void createAndOptimizeReplicateRegions(VPlan &Plan); 45 46 /// Remove redundant VPBasicBlocks by merging them into their predecessor if 47 /// the predecessor has a single successor. 48 static bool mergeBlocksIntoPredecessors(VPlan &Plan); 49 50 /// Remove redundant casts of inductions. 51 /// 52 /// Such redundant casts are casts of induction variables that can be ignored, 53 /// because we already proved that the casted phi is equal to the uncasted phi 54 /// in the vectorized loop. There is no need to vectorize the cast - the same 55 /// value can be used for both the phi and casts in the vector loop. 56 static void removeRedundantInductionCasts(VPlan &Plan); 57 58 /// Try to replace VPWidenCanonicalIVRecipes with a widened canonical IV 59 /// recipe, if it exists. 60 static void removeRedundantCanonicalIVs(VPlan &Plan); 61 62 static void removeDeadRecipes(VPlan &Plan); 63 64 /// If any user of a VPWidenIntOrFpInductionRecipe needs scalar values, 65 /// provide them by building scalar steps off of the canonical scalar IV and 66 /// update the original IV's users. This is an optional optimization to reduce 67 /// the needs of vector extracts. 68 static void optimizeInductions(VPlan &Plan, ScalarEvolution &SE); 69 70 /// Remove redundant EpxandSCEVRecipes in \p Plan's entry block by replacing 71 /// them with already existing recipes expanding the same SCEV expression. 72 static void removeRedundantExpandSCEVRecipes(VPlan &Plan); 73 74 /// Sink users of fixed-order recurrences after the recipe defining their 75 /// previous value. Then introduce FirstOrderRecurrenceSplice VPInstructions 76 /// to combine the value from the recurrence phis and previous values. The 77 /// current implementation assumes all users can be sunk after the previous 78 /// value, which is enforced by earlier legality checks. 79 /// \returns true if all users of fixed-order recurrences could be re-arranged 80 /// as needed or false if it is not possible. In the latter case, \p Plan is 81 /// not valid. 82 static bool adjustFixedOrderRecurrences(VPlan &Plan, VPBuilder &Builder); 83 84 /// Clear NSW/NUW flags from reduction instructions if necessary. 85 static void clearReductionWrapFlags(VPlan &Plan); 86 87 /// Optimize \p Plan based on \p BestVF and \p BestUF. This may restrict the 88 /// resulting plan to \p BestVF and \p BestUF. 89 static void optimizeForVFAndUF(VPlan &Plan, ElementCount BestVF, 90 unsigned BestUF, 91 PredicatedScalarEvolution &PSE); 92 }; 93 94 } // namespace llvm 95 96 #endif // LLVM_TRANSFORMS_VECTORIZE_VPLANTRANSFORMS_H 97