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//===- SeedCollector.cpp -------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h"
#include "llvm/Analysis/LoopAccessAnalysis.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Type.h"
#include "llvm/SandboxIR/Instruction.h"
#include "llvm/SandboxIR/Utils.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
namespace llvm::sandboxir {
static cl::opt<unsigned> SeedBundleSizeLimit(
"sbvec-seed-bundle-size-limit", cl::init(32), cl::Hidden,
cl::desc("Limit the size of the seed bundle to cap compilation time."));
static cl::opt<unsigned> SeedGroupsLimit(
"sbvec-seed-groups-limit", cl::init(256), cl::Hidden,
cl::desc("Limit the number of collected seeds groups in a BB to "
"cap compilation time."));
ArrayRef<Instruction *> SeedBundle::getSlice(unsigned StartIdx,
unsigned MaxVecRegBits,
bool ForcePowerOf2) {
// Use uint32_t here for compatibility with IsPowerOf2_32
// BitCount tracks the size of the working slice. From that we can tell
// when the working slice's size is a power-of-two and when it exceeds
// the legal size in MaxVecBits.
uint32_t BitCount = 0;
uint32_t NumElements = 0;
// Tracks the most recent slice where NumElements gave a power-of-2 BitCount
uint32_t NumElementsPowerOfTwo = 0;
uint32_t BitCountPowerOfTwo = 0;
// Can't start a slice with a used instruction.
assert(!isUsed(StartIdx) && "Expected unused at StartIdx");
for (Instruction *S : drop_begin(Seeds, StartIdx)) {
// Stop if this instruction is used. This needs to be done before
// getNumBits() because a "used" instruction may have been erased.
if (isUsed(StartIdx + NumElements))
break;
uint32_t InstBits = Utils::getNumBits(S);
// Stop if adding it puts the slice over the limit.
if (BitCount + InstBits > MaxVecRegBits)
break;
NumElements++;
BitCount += InstBits;
if (ForcePowerOf2 && isPowerOf2_32(BitCount)) {
NumElementsPowerOfTwo = NumElements;
BitCountPowerOfTwo = BitCount;
}
}
if (ForcePowerOf2) {
NumElements = NumElementsPowerOfTwo;
BitCount = BitCountPowerOfTwo;
}
// Return any non-empty slice
if (NumElements > 1) {
assert((!ForcePowerOf2 || isPowerOf2_32(BitCount)) &&
"Must be a power of two");
return ArrayRef<Instruction *>(&Seeds[StartIdx], NumElements);
}
return {};
}
template <typename LoadOrStoreT>
SeedContainer::KeyT SeedContainer::getKey(LoadOrStoreT *LSI) const {
assert((isa<LoadInst>(LSI) || isa<StoreInst>(LSI)) &&
"Expected Load or Store!");
Value *Ptr = Utils::getMemInstructionBase(LSI);
Instruction::Opcode Op = LSI->getOpcode();
Type *Ty = Utils::getExpectedType(LSI);
if (auto *VTy = dyn_cast<VectorType>(Ty))
Ty = VTy->getElementType();
return {Ptr, Ty, Op};
}
// Explicit instantiations
template SeedContainer::KeyT
SeedContainer::getKey<LoadInst>(LoadInst *LSI) const;
template SeedContainer::KeyT
SeedContainer::getKey<StoreInst>(StoreInst *LSI) const;
bool SeedContainer::erase(Instruction *I) {
assert((isa<LoadInst>(I) || isa<StoreInst>(I)) && "Expected Load or Store!");
auto It = SeedLookupMap.find(I);
if (It == SeedLookupMap.end())
return false;
SeedBundle *Bndl = It->second;
Bndl->setUsed(I);
return true;
}
template <typename LoadOrStoreT> void SeedContainer::insert(LoadOrStoreT *LSI) {
// Find the bundle containing seeds for this symbol and type-of-access.
auto &BundleVec = Bundles[getKey(LSI)];
// Fill this vector of bundles front to back so that only the last bundle in
// the vector may have available space. This avoids iteration to find one with
// space.
if (BundleVec.empty() || BundleVec.back()->size() == SeedBundleSizeLimit)
BundleVec.emplace_back(std::make_unique<MemSeedBundle<LoadOrStoreT>>(LSI));
else
BundleVec.back()->insert(LSI, SE);
SeedLookupMap[LSI] = BundleVec.back().get();
}
// Explicit instantiations
template LLVM_EXPORT_TEMPLATE void SeedContainer::insert<LoadInst>(LoadInst *);
template LLVM_EXPORT_TEMPLATE void
SeedContainer::insert<StoreInst>(StoreInst *);
#ifndef NDEBUG
void SeedContainer::print(raw_ostream &OS) const {
for (const auto &Pair : Bundles) {
auto [I, Ty, Opc] = Pair.first;
const auto &SeedsVec = Pair.second;
std::string RefType = dyn_cast<LoadInst>(I) ? "Load"
: dyn_cast<StoreInst>(I) ? "Store"
: "Other";
OS << "[Inst=" << *I << " Ty=" << Ty << " " << RefType << "]\n";
for (const auto &SeedPtr : SeedsVec) {
SeedPtr->dump(OS);
OS << "\n";
}
}
OS << "\n";
}
LLVM_DUMP_METHOD void SeedContainer::dump() const { print(dbgs()); }
#endif // NDEBUG
template <typename LoadOrStoreT> static bool isValidMemSeed(LoadOrStoreT *LSI) {
if (!LSI->isSimple())
return false;
auto *Ty = Utils::getExpectedType(LSI);
// Omit types that are architecturally unvectorizable
if (Ty->isX86_FP80Ty() || Ty->isPPC_FP128Ty())
return false;
// Omit vector types without compile-time-known lane counts
if (isa<ScalableVectorType>(Ty))
return false;
if (auto *VTy = dyn_cast<FixedVectorType>(Ty))
return VectorType::isValidElementType(VTy->getElementType());
return VectorType::isValidElementType(Ty);
}
template bool isValidMemSeed<LoadInst>(LoadInst *LSI);
template bool isValidMemSeed<StoreInst>(StoreInst *LSI);
SeedCollector::SeedCollector(BasicBlock *BB, ScalarEvolution &SE,
bool CollectStores, bool CollectLoads)
: StoreSeeds(SE), LoadSeeds(SE), Ctx(BB->getContext()) {
if (!CollectStores && !CollectLoads)
return;
EraseCallbackID = Ctx.registerEraseInstrCallback([this](Instruction *I) {
if (auto SI = dyn_cast<StoreInst>(I))
StoreSeeds.erase(SI);
else if (auto LI = dyn_cast<LoadInst>(I))
LoadSeeds.erase(LI);
});
// Actually collect the seeds.
for (auto &I : *BB) {
if (StoreInst *SI = dyn_cast<StoreInst>(&I))
if (CollectStores && isValidMemSeed(SI))
StoreSeeds.insert(SI);
if (LoadInst *LI = dyn_cast<LoadInst>(&I))
if (CollectLoads && isValidMemSeed(LI))
LoadSeeds.insert(LI);
// Cap compilation time.
if (totalNumSeedGroups() > SeedGroupsLimit)
break;
}
}
SeedCollector::~SeedCollector() {
Ctx.unregisterEraseInstrCallback(EraseCallbackID);
}
#ifndef NDEBUG
void SeedCollector::print(raw_ostream &OS) const {
OS << "=== StoreSeeds ===\n";
StoreSeeds.print(OS);
OS << "=== LoadSeeds ===\n";
LoadSeeds.print(OS);
}
void SeedCollector::dump() const { print(dbgs()); }
#endif
} // namespace llvm::sandboxir
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