106 lines · cpp
1//===- SeedCollection.cpp - Seed collection pass --------------------------===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/SeedCollection.h"10#include "llvm/Analysis/TargetTransformInfo.h"11#include "llvm/SandboxIR/Module.h"12#include "llvm/SandboxIR/Region.h"13#include "llvm/Transforms/Vectorize/SandboxVectorizer/SandboxVectorizerPassBuilder.h"14#include "llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h"15#include "llvm/Transforms/Vectorize/SandboxVectorizer/VecUtils.h"16 17namespace llvm {18 19static cl::opt<unsigned>20 OverrideVecRegBits("sbvec-vec-reg-bits", cl::init(0), cl::Hidden,21 cl::desc("Override the vector register size in bits, "22 "which is otherwise found by querying TTI."));23static cl::opt<bool>24 AllowNonPow2("sbvec-allow-non-pow2", cl::init(false), cl::Hidden,25 cl::desc("Allow non-power-of-2 vectorization."));26 27#define LoadSeedsDef "loads"28#define StoreSeedsDef "stores"29cl::opt<std::string> CollectSeeds(30 "sbvec-collect-seeds", cl::init(StoreSeedsDef), cl::Hidden,31 cl::desc("Collect these seeds. Use empty for none or a comma-separated "32 "list of '" StoreSeedsDef "' and '" LoadSeedsDef "'."));33 34namespace sandboxir {35SeedCollection::SeedCollection(StringRef Pipeline)36 : FunctionPass("seed-collection"),37 RPM("rpm", Pipeline, SandboxVectorizerPassBuilder::createRegionPass) {}38 39bool SeedCollection::runOnFunction(Function &F, const Analyses &A) {40 bool Change = false;41 const auto &DL = F.getParent()->getDataLayout();42 unsigned VecRegBits =43 OverrideVecRegBits != 044 ? OverrideVecRegBits45 : A.getTTI()46 .getRegisterBitWidth(TargetTransformInfo::RGK_FixedWidthVector)47 .getFixedValue();48 bool CollectStores = CollectSeeds.find(StoreSeedsDef) != std::string::npos;49 bool CollectLoads = CollectSeeds.find(LoadSeedsDef) != std::string::npos;50 51 // TODO: Start from innermost BBs first52 for (auto &BB : F) {53 SeedCollector SC(&BB, A.getScalarEvolution(), CollectStores, CollectLoads);54 for (SeedBundle &Seeds : SC.getStoreSeeds()) {55 unsigned ElmBits =56 Utils::getNumBits(VecUtils::getElementType(Utils::getExpectedType(57 Seeds[Seeds.getFirstUnusedElementIdx()])),58 DL);59 60 auto DivideBy2 = [](unsigned Num) {61 auto Floor = VecUtils::getFloorPowerOf2(Num);62 if (Floor == Num)63 return Floor / 2;64 return Floor;65 };66 // Try to create the largest vector supported by the target. If it fails67 // reduce the vector size by half.68 for (unsigned SliceElms = std::min(VecRegBits / ElmBits,69 Seeds.getNumUnusedBits() / ElmBits);70 SliceElms >= 2u; SliceElms = DivideBy2(SliceElms)) {71 if (Seeds.allUsed())72 break;73 // Keep trying offsets after FirstUnusedElementIdx, until we vectorize74 // the slice. This could be quite expensive, so we enforce a limit.75 for (unsigned Offset = Seeds.getFirstUnusedElementIdx(),76 OE = Seeds.size();77 Offset + 1 < OE; Offset += 1) {78 // Seeds are getting used as we vectorize, so skip them.79 if (Seeds.isUsed(Offset))80 continue;81 if (Seeds.allUsed())82 break;83 84 auto SeedSlice =85 Seeds.getSlice(Offset, SliceElms * ElmBits, !AllowNonPow2);86 if (SeedSlice.empty())87 continue;88 89 assert(SeedSlice.size() >= 2 && "Should have been rejected!");90 91 // Create a region containing the seed slice.92 auto &Ctx = F.getContext();93 Region Rgn(Ctx, A.getTTI());94 Rgn.setAux(SeedSlice);95 // Run the region pass pipeline.96 Change |= RPM.runOnRegion(Rgn, A);97 Rgn.clearAux();98 }99 }100 }101 }102 return Change;103}104} // namespace sandboxir105} // namespace llvm106