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authorDimitry Andric <dim@FreeBSD.org>2019-12-20 19:53:05 +0000
committerDimitry Andric <dim@FreeBSD.org>2019-12-20 19:53:05 +0000
commit0b57cec536236d46e3dba9bd041533462f33dbb7 (patch)
tree56229dbdbbf76d18580f72f789003db17246c8d9 /contrib/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
parent718ef55ec7785aae63f98f8ca05dc07ed399c16d (diff)
Notes
Diffstat (limited to 'contrib/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp')
-rw-r--r--contrib/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp1248
1 files changed, 0 insertions, 1248 deletions
diff --git a/contrib/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp b/contrib/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
deleted file mode 100644
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--- a/contrib/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
+++ /dev/null
@@ -1,1248 +0,0 @@
-//===- LoadStoreVectorizer.cpp - GPU Load & Store Vectorizer --------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass merges loads/stores to/from sequential memory addresses into vector
-// loads/stores. Although there's nothing GPU-specific in here, this pass is
-// motivated by the microarchitectural quirks of nVidia and AMD GPUs.
-//
-// (For simplicity below we talk about loads only, but everything also applies
-// to stores.)
-//
-// This pass is intended to be run late in the pipeline, after other
-// vectorization opportunities have been exploited. So the assumption here is
-// that immediately following our new vector load we'll need to extract out the
-// individual elements of the load, so we can operate on them individually.
-//
-// On CPUs this transformation is usually not beneficial, because extracting the
-// elements of a vector register is expensive on most architectures. It's
-// usually better just to load each element individually into its own scalar
-// register.
-//
-// However, nVidia and AMD GPUs don't have proper vector registers. Instead, a
-// "vector load" loads directly into a series of scalar registers. In effect,
-// extracting the elements of the vector is free. It's therefore always
-// beneficial to vectorize a sequence of loads on these architectures.
-//
-// Vectorizing (perhaps a better name might be "coalescing") loads can have
-// large performance impacts on GPU kernels, and opportunities for vectorizing
-// are common in GPU code. This pass tries very hard to find such
-// opportunities; its runtime is quadratic in the number of loads in a BB.
-//
-// Some CPU architectures, such as ARM, have instructions that load into
-// multiple scalar registers, similar to a GPU vectorized load. In theory ARM
-// could use this pass (with some modifications), but currently it implements
-// its own pass to do something similar to what we do here.
-
-#include "llvm/ADT/APInt.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/MapVector.h"
-#include "llvm/ADT/PostOrderIterator.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/iterator_range.h"
-#include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/Analysis/MemoryLocation.h"
-#include "llvm/Analysis/OrderedBasicBlock.h"
-#include "llvm/Analysis/ScalarEvolution.h"
-#include "llvm/Analysis/TargetTransformInfo.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Analysis/VectorUtils.h"
-#include "llvm/IR/Attributes.h"
-#include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DataLayout.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/InstrTypes.h"
-#include "llvm/IR/Instruction.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/Type.h"
-#include "llvm/IR/User.h"
-#include "llvm/IR/Value.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/KnownBits.h"
-#include "llvm/Support/MathExtras.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Transforms/Vectorize.h"
-#include "llvm/Transforms/Vectorize/LoadStoreVectorizer.h"
-#include <algorithm>
-#include <cassert>
-#include <cstdlib>
-#include <tuple>
-#include <utility>
-
-using namespace llvm;
-
-#define DEBUG_TYPE "load-store-vectorizer"
-
-STATISTIC(NumVectorInstructions, "Number of vector accesses generated");
-STATISTIC(NumScalarsVectorized, "Number of scalar accesses vectorized");
-
-// FIXME: Assuming stack alignment of 4 is always good enough
-static const unsigned StackAdjustedAlignment = 4;
-
-namespace {
-
-/// ChainID is an arbitrary token that is allowed to be different only for the
-/// accesses that are guaranteed to be considered non-consecutive by
-/// Vectorizer::isConsecutiveAccess. It's used for grouping instructions
-/// together and reducing the number of instructions the main search operates on
-/// at a time, i.e. this is to reduce compile time and nothing else as the main
-/// search has O(n^2) time complexity. The underlying type of ChainID should not
-/// be relied upon.
-using ChainID = const Value *;
-using InstrList = SmallVector<Instruction *, 8>;
-using InstrListMap = MapVector<ChainID, InstrList>;
-
-class Vectorizer {
- Function &F;
- AliasAnalysis &AA;
- DominatorTree &DT;
- ScalarEvolution &SE;
- TargetTransformInfo &TTI;
- const DataLayout &DL;
- IRBuilder<> Builder;
-
-public:
- Vectorizer(Function &F, AliasAnalysis &AA, DominatorTree &DT,
- ScalarEvolution &SE, TargetTransformInfo &TTI)
- : F(F), AA(AA), DT(DT), SE(SE), TTI(TTI),
- DL(F.getParent()->getDataLayout()), Builder(SE.getContext()) {}
-
- bool run();
-
-private:
- unsigned getPointerAddressSpace(Value *I);
-
- unsigned getAlignment(LoadInst *LI) const {
- unsigned Align = LI->getAlignment();
- if (Align != 0)
- return Align;
-
- return DL.getABITypeAlignment(LI->getType());
- }
-
- unsigned getAlignment(StoreInst *SI) const {
- unsigned Align = SI->getAlignment();
- if (Align != 0)
- return Align;
-
- return DL.getABITypeAlignment(SI->getValueOperand()->getType());
- }
-
- static const unsigned MaxDepth = 3;
-
- bool isConsecutiveAccess(Value *A, Value *B);
- bool areConsecutivePointers(Value *PtrA, Value *PtrB, const APInt &PtrDelta,
- unsigned Depth = 0) const;
- bool lookThroughComplexAddresses(Value *PtrA, Value *PtrB, APInt PtrDelta,
- unsigned Depth) const;
- bool lookThroughSelects(Value *PtrA, Value *PtrB, const APInt &PtrDelta,
- unsigned Depth) const;
-
- /// After vectorization, reorder the instructions that I depends on
- /// (the instructions defining its operands), to ensure they dominate I.
- void reorder(Instruction *I);
-
- /// Returns the first and the last instructions in Chain.
- std::pair<BasicBlock::iterator, BasicBlock::iterator>
- getBoundaryInstrs(ArrayRef<Instruction *> Chain);
-
- /// Erases the original instructions after vectorizing.
- void eraseInstructions(ArrayRef<Instruction *> Chain);
-
- /// "Legalize" the vector type that would be produced by combining \p
- /// ElementSizeBits elements in \p Chain. Break into two pieces such that the
- /// total size of each piece is 1, 2 or a multiple of 4 bytes. \p Chain is
- /// expected to have more than 4 elements.
- std::pair<ArrayRef<Instruction *>, ArrayRef<Instruction *>>
- splitOddVectorElts(ArrayRef<Instruction *> Chain, unsigned ElementSizeBits);
-
- /// Finds the largest prefix of Chain that's vectorizable, checking for
- /// intervening instructions which may affect the memory accessed by the
- /// instructions within Chain.
- ///
- /// The elements of \p Chain must be all loads or all stores and must be in
- /// address order.
- ArrayRef<Instruction *> getVectorizablePrefix(ArrayRef<Instruction *> Chain);
-
- /// Collects load and store instructions to vectorize.
- std::pair<InstrListMap, InstrListMap> collectInstructions(BasicBlock *BB);
-
- /// Processes the collected instructions, the \p Map. The values of \p Map
- /// should be all loads or all stores.
- bool vectorizeChains(InstrListMap &Map);
-
- /// Finds the load/stores to consecutive memory addresses and vectorizes them.
- bool vectorizeInstructions(ArrayRef<Instruction *> Instrs);
-
- /// Vectorizes the load instructions in Chain.
- bool
- vectorizeLoadChain(ArrayRef<Instruction *> Chain,
- SmallPtrSet<Instruction *, 16> *InstructionsProcessed);
-
- /// Vectorizes the store instructions in Chain.
- bool
- vectorizeStoreChain(ArrayRef<Instruction *> Chain,
- SmallPtrSet<Instruction *, 16> *InstructionsProcessed);
-
- /// Check if this load/store access is misaligned accesses.
- bool accessIsMisaligned(unsigned SzInBytes, unsigned AddressSpace,
- unsigned Alignment);
-};
-
-class LoadStoreVectorizerLegacyPass : public FunctionPass {
-public:
- static char ID;
-
- LoadStoreVectorizerLegacyPass() : FunctionPass(ID) {
- initializeLoadStoreVectorizerLegacyPassPass(*PassRegistry::getPassRegistry());
- }
-
- bool runOnFunction(Function &F) override;
-
- StringRef getPassName() const override {
- return "GPU Load and Store Vectorizer";
- }
-
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.addRequired<AAResultsWrapperPass>();
- AU.addRequired<ScalarEvolutionWrapperPass>();
- AU.addRequired<DominatorTreeWrapperPass>();
- AU.addRequired<TargetTransformInfoWrapperPass>();
- AU.setPreservesCFG();
- }
-};
-
-} // end anonymous namespace
-
-char LoadStoreVectorizerLegacyPass::ID = 0;
-
-INITIALIZE_PASS_BEGIN(LoadStoreVectorizerLegacyPass, DEBUG_TYPE,
- "Vectorize load and Store instructions", false, false)
-INITIALIZE_PASS_DEPENDENCY(SCEVAAWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
-INITIALIZE_PASS_END(LoadStoreVectorizerLegacyPass, DEBUG_TYPE,
- "Vectorize load and store instructions", false, false)
-
-Pass *llvm::createLoadStoreVectorizerPass() {
- return new LoadStoreVectorizerLegacyPass();
-}
-
-bool LoadStoreVectorizerLegacyPass::runOnFunction(Function &F) {
- // Don't vectorize when the attribute NoImplicitFloat is used.
- if (skipFunction(F) || F.hasFnAttribute(Attribute::NoImplicitFloat))
- return false;
-
- AliasAnalysis &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
- DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
- ScalarEvolution &SE = getAnalysis<ScalarEvolutionWrapperPass>().getSE();
- TargetTransformInfo &TTI =
- getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
-
- Vectorizer V(F, AA, DT, SE, TTI);
- return V.run();
-}
-
-PreservedAnalyses LoadStoreVectorizerPass::run(Function &F, FunctionAnalysisManager &AM) {
- // Don't vectorize when the attribute NoImplicitFloat is used.
- if (F.hasFnAttribute(Attribute::NoImplicitFloat))
- return PreservedAnalyses::all();
-
- AliasAnalysis &AA = AM.getResult<AAManager>(F);
- DominatorTree &DT = AM.getResult<DominatorTreeAnalysis>(F);
- ScalarEvolution &SE = AM.getResult<ScalarEvolutionAnalysis>(F);
- TargetTransformInfo &TTI = AM.getResult<TargetIRAnalysis>(F);
-
- Vectorizer V(F, AA, DT, SE, TTI);
- bool Changed = V.run();
- PreservedAnalyses PA;
- PA.preserveSet<CFGAnalyses>();
- return Changed ? PA : PreservedAnalyses::all();
-}
-
-// The real propagateMetadata expects a SmallVector<Value*>, but we deal in
-// vectors of Instructions.
-static void propagateMetadata(Instruction *I, ArrayRef<Instruction *> IL) {
- SmallVector<Value *, 8> VL(IL.begin(), IL.end());
- propagateMetadata(I, VL);
-}
-
-// Vectorizer Implementation
-bool Vectorizer::run() {
- bool Changed = false;
-
- // Scan the blocks in the function in post order.
- for (BasicBlock *BB : post_order(&F)) {
- InstrListMap LoadRefs, StoreRefs;
- std::tie(LoadRefs, StoreRefs) = collectInstructions(BB);
- Changed |= vectorizeChains(LoadRefs);
- Changed |= vectorizeChains(StoreRefs);
- }
-
- return Changed;
-}
-
-unsigned Vectorizer::getPointerAddressSpace(Value *I) {
- if (LoadInst *L = dyn_cast<LoadInst>(I))
- return L->getPointerAddressSpace();
- if (StoreInst *S = dyn_cast<StoreInst>(I))
- return S->getPointerAddressSpace();
- return -1;
-}
-
-// FIXME: Merge with llvm::isConsecutiveAccess
-bool Vectorizer::isConsecutiveAccess(Value *A, Value *B) {
- Value *PtrA = getLoadStorePointerOperand(A);
- Value *PtrB = getLoadStorePointerOperand(B);
- unsigned ASA = getPointerAddressSpace(A);
- unsigned ASB = getPointerAddressSpace(B);
-
- // Check that the address spaces match and that the pointers are valid.
- if (!PtrA || !PtrB || (ASA != ASB))
- return false;
-
- // Make sure that A and B are different pointers of the same size type.
- Type *PtrATy = PtrA->getType()->getPointerElementType();
- Type *PtrBTy = PtrB->getType()->getPointerElementType();
- if (PtrA == PtrB ||
- PtrATy->isVectorTy() != PtrBTy->isVectorTy() ||
- DL.getTypeStoreSize(PtrATy) != DL.getTypeStoreSize(PtrBTy) ||
- DL.getTypeStoreSize(PtrATy->getScalarType()) !=
- DL.getTypeStoreSize(PtrBTy->getScalarType()))
- return false;
-
- unsigned PtrBitWidth = DL.getPointerSizeInBits(ASA);
- APInt Size(PtrBitWidth, DL.getTypeStoreSize(PtrATy));
-
- return areConsecutivePointers(PtrA, PtrB, Size);
-}
-
-bool Vectorizer::areConsecutivePointers(Value *PtrA, Value *PtrB,
- const APInt &PtrDelta,
- unsigned Depth) const {
- unsigned PtrBitWidth = DL.getPointerTypeSizeInBits(PtrA->getType());
- APInt OffsetA(PtrBitWidth, 0);
- APInt OffsetB(PtrBitWidth, 0);
- PtrA = PtrA->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetA);
- PtrB = PtrB->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetB);
-
- APInt OffsetDelta = OffsetB - OffsetA;
-
- // Check if they are based on the same pointer. That makes the offsets
- // sufficient.
- if (PtrA == PtrB)
- return OffsetDelta == PtrDelta;
-
- // Compute the necessary base pointer delta to have the necessary final delta
- // equal to the pointer delta requested.
- APInt BaseDelta = PtrDelta - OffsetDelta;
-
- // Compute the distance with SCEV between the base pointers.
- const SCEV *PtrSCEVA = SE.getSCEV(PtrA);
- const SCEV *PtrSCEVB = SE.getSCEV(PtrB);
- const SCEV *C = SE.getConstant(BaseDelta);
- const SCEV *X = SE.getAddExpr(PtrSCEVA, C);
- if (X == PtrSCEVB)
- return true;
-
- // The above check will not catch the cases where one of the pointers is
- // factorized but the other one is not, such as (C + (S * (A + B))) vs
- // (AS + BS). Get the minus scev. That will allow re-combining the expresions
- // and getting the simplified difference.
- const SCEV *Dist = SE.getMinusSCEV(PtrSCEVB, PtrSCEVA);
- if (C == Dist)
- return true;
-
- // Sometimes even this doesn't work, because SCEV can't always see through
- // patterns that look like (gep (ext (add (shl X, C1), C2))). Try checking
- // things the hard way.
- return lookThroughComplexAddresses(PtrA, PtrB, BaseDelta, Depth);
-}
-
-bool Vectorizer::lookThroughComplexAddresses(Value *PtrA, Value *PtrB,
- APInt PtrDelta,
- unsigned Depth) const {
- auto *GEPA = dyn_cast<GetElementPtrInst>(PtrA);
- auto *GEPB = dyn_cast<GetElementPtrInst>(PtrB);
- if (!GEPA || !GEPB)
- return lookThroughSelects(PtrA, PtrB, PtrDelta, Depth);
-
- // Look through GEPs after checking they're the same except for the last
- // index.
- if (GEPA->getNumOperands() != GEPB->getNumOperands() ||
- GEPA->getPointerOperand() != GEPB->getPointerOperand())
- return false;
- gep_type_iterator GTIA = gep_type_begin(GEPA);
- gep_type_iterator GTIB = gep_type_begin(GEPB);
- for (unsigned I = 0, E = GEPA->getNumIndices() - 1; I < E; ++I) {
- if (GTIA.getOperand() != GTIB.getOperand())
- return false;
- ++GTIA;
- ++GTIB;
- }
-
- Instruction *OpA = dyn_cast<Instruction>(GTIA.getOperand());
- Instruction *OpB = dyn_cast<Instruction>(GTIB.getOperand());
- if (!OpA || !OpB || OpA->getOpcode() != OpB->getOpcode() ||
- OpA->getType() != OpB->getType())
- return false;
-
- if (PtrDelta.isNegative()) {
- if (PtrDelta.isMinSignedValue())
- return false;
- PtrDelta.negate();
- std::swap(OpA, OpB);
- }
- uint64_t Stride = DL.getTypeAllocSize(GTIA.getIndexedType());
- if (PtrDelta.urem(Stride) != 0)
- return false;
- unsigned IdxBitWidth = OpA->getType()->getScalarSizeInBits();
- APInt IdxDiff = PtrDelta.udiv(Stride).zextOrSelf(IdxBitWidth);
-
- // Only look through a ZExt/SExt.
- if (!isa<SExtInst>(OpA) && !isa<ZExtInst>(OpA))
- return false;
-
- bool Signed = isa<SExtInst>(OpA);
-
- // At this point A could be a function parameter, i.e. not an instruction
- Value *ValA = OpA->getOperand(0);
- OpB = dyn_cast<Instruction>(OpB->getOperand(0));
- if (!OpB || ValA->getType() != OpB->getType())
- return false;
-
- // Now we need to prove that adding IdxDiff to ValA won't overflow.
- bool Safe = false;
- // First attempt: if OpB is an add with NSW/NUW, and OpB is IdxDiff added to
- // ValA, we're okay.
- if (OpB->getOpcode() == Instruction::Add &&
- isa<ConstantInt>(OpB->getOperand(1)) &&
- IdxDiff.sle(cast<ConstantInt>(OpB->getOperand(1))->getSExtValue())) {
- if (Signed)
- Safe = cast<BinaryOperator>(OpB)->hasNoSignedWrap();
- else
- Safe = cast<BinaryOperator>(OpB)->hasNoUnsignedWrap();
- }
-
- unsigned BitWidth = ValA->getType()->getScalarSizeInBits();
-
- // Second attempt:
- // If all set bits of IdxDiff or any higher order bit other than the sign bit
- // are known to be zero in ValA, we can add Diff to it while guaranteeing no
- // overflow of any sort.
- if (!Safe) {
- OpA = dyn_cast<Instruction>(ValA);
- if (!OpA)
- return false;
- KnownBits Known(BitWidth);
- computeKnownBits(OpA, Known, DL, 0, nullptr, OpA, &DT);
- APInt BitsAllowedToBeSet = Known.Zero.zext(IdxDiff.getBitWidth());
- if (Signed)
- BitsAllowedToBeSet.clearBit(BitWidth - 1);
- if (BitsAllowedToBeSet.ult(IdxDiff))
- return false;
- }
-
- const SCEV *OffsetSCEVA = SE.getSCEV(ValA);
- const SCEV *OffsetSCEVB = SE.getSCEV(OpB);
- const SCEV *C = SE.getConstant(IdxDiff.trunc(BitWidth));
- const SCEV *X = SE.getAddExpr(OffsetSCEVA, C);
- return X == OffsetSCEVB;
-}
-
-bool Vectorizer::lookThroughSelects(Value *PtrA, Value *PtrB,
- const APInt &PtrDelta,
- unsigned Depth) const {
- if (Depth++ == MaxDepth)
- return false;
-
- if (auto *SelectA = dyn_cast<SelectInst>(PtrA)) {
- if (auto *SelectB = dyn_cast<SelectInst>(PtrB)) {
- return SelectA->getCondition() == SelectB->getCondition() &&
- areConsecutivePointers(SelectA->getTrueValue(),
- SelectB->getTrueValue(), PtrDelta, Depth) &&
- areConsecutivePointers(SelectA->getFalseValue(),
- SelectB->getFalseValue(), PtrDelta, Depth);
- }
- }
- return false;
-}
-
-void Vectorizer::reorder(Instruction *I) {
- OrderedBasicBlock OBB(I->getParent());
- SmallPtrSet<Instruction *, 16> InstructionsToMove;
- SmallVector<Instruction *, 16> Worklist;
-
- Worklist.push_back(I);
- while (!Worklist.empty()) {
- Instruction *IW = Worklist.pop_back_val();
- int NumOperands = IW->getNumOperands();
- for (int i = 0; i < NumOperands; i++) {
- Instruction *IM = dyn_cast<Instruction>(IW->getOperand(i));
- if (!IM || IM->getOpcode() == Instruction::PHI)
- continue;
-
- // If IM is in another BB, no need to move it, because this pass only
- // vectorizes instructions within one BB.
- if (IM->getParent() != I->getParent())
- continue;
-
- if (!OBB.dominates(IM, I)) {
- InstructionsToMove.insert(IM);
- Worklist.push_back(IM);
- }
- }
- }
-
- // All instructions to move should follow I. Start from I, not from begin().
- for (auto BBI = I->getIterator(), E = I->getParent()->end(); BBI != E;
- ++BBI) {
- if (!InstructionsToMove.count(&*BBI))
- continue;
- Instruction *IM = &*BBI;
- --BBI;
- IM->removeFromParent();
- IM->insertBefore(I);
- }
-}
-
-std::pair<BasicBlock::iterator, BasicBlock::iterator>
-Vectorizer::getBoundaryInstrs(ArrayRef<Instruction *> Chain) {
- Instruction *C0 = Chain[0];
- BasicBlock::iterator FirstInstr = C0->getIterator();
- BasicBlock::iterator LastInstr = C0->getIterator();
-
- BasicBlock *BB = C0->getParent();
- unsigned NumFound = 0;
- for (Instruction &I : *BB) {
- if (!is_contained(Chain, &I))
- continue;
-
- ++NumFound;
- if (NumFound == 1) {
- FirstInstr = I.getIterator();
- }
- if (NumFound == Chain.size()) {
- LastInstr = I.getIterator();
- break;
- }
- }
-
- // Range is [first, last).
- return std::make_pair(FirstInstr, ++LastInstr);
-}
-
-void Vectorizer::eraseInstructions(ArrayRef<Instruction *> Chain) {
- SmallVector<Instruction *, 16> Instrs;
- for (Instruction *I : Chain) {
- Value *PtrOperand = getLoadStorePointerOperand(I);
- assert(PtrOperand && "Instruction must have a pointer operand.");
- Instrs.push_back(I);
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(PtrOperand))
- Instrs.push_back(GEP);
- }
-
- // Erase instructions.
- for (Instruction *I : Instrs)
- if (I->use_empty())
- I->eraseFromParent();
-}
-
-std::pair<ArrayRef<Instruction *>, ArrayRef<Instruction *>>
-Vectorizer::splitOddVectorElts(ArrayRef<Instruction *> Chain,
- unsigned ElementSizeBits) {
- unsigned ElementSizeBytes = ElementSizeBits / 8;
- unsigned SizeBytes = ElementSizeBytes * Chain.size();
- unsigned NumLeft = (SizeBytes - (SizeBytes % 4)) / ElementSizeBytes;
- if (NumLeft == Chain.size()) {
- if ((NumLeft & 1) == 0)
- NumLeft /= 2; // Split even in half
- else
- --NumLeft; // Split off last element
- } else if (NumLeft == 0)
- NumLeft = 1;
- return std::make_pair(Chain.slice(0, NumLeft), Chain.slice(NumLeft));
-}
-
-ArrayRef<Instruction *>
-Vectorizer::getVectorizablePrefix(ArrayRef<Instruction *> Chain) {
- // These are in BB order, unlike Chain, which is in address order.
- SmallVector<Instruction *, 16> MemoryInstrs;
- SmallVector<Instruction *, 16> ChainInstrs;
-
- bool IsLoadChain = isa<LoadInst>(Chain[0]);
- LLVM_DEBUG({
- for (Instruction *I : Chain) {
- if (IsLoadChain)
- assert(isa<LoadInst>(I) &&
- "All elements of Chain must be loads, or all must be stores.");
- else
- assert(isa<StoreInst>(I) &&
- "All elements of Chain must be loads, or all must be stores.");
- }
- });
-
- for (Instruction &I : make_range(getBoundaryInstrs(Chain))) {
- if (isa<LoadInst>(I) || isa<StoreInst>(I)) {
- if (!is_contained(Chain, &I))
- MemoryInstrs.push_back(&I);
- else
- ChainInstrs.push_back(&I);
- } else if (isa<IntrinsicInst>(&I) &&
- cast<IntrinsicInst>(&I)->getIntrinsicID() ==
- Intrinsic::sideeffect) {
- // Ignore llvm.sideeffect calls.
- } else if (IsLoadChain && (I.mayWriteToMemory() || I.mayThrow())) {
- LLVM_DEBUG(dbgs() << "LSV: Found may-write/throw operation: " << I
- << '\n');
- break;
- } else if (!IsLoadChain && (I.mayReadOrWriteMemory() || I.mayThrow())) {
- LLVM_DEBUG(dbgs() << "LSV: Found may-read/write/throw operation: " << I
- << '\n');
- break;
- }
- }
-
- OrderedBasicBlock OBB(Chain[0]->getParent());
-
- // Loop until we find an instruction in ChainInstrs that we can't vectorize.
- unsigned ChainInstrIdx = 0;
- Instruction *BarrierMemoryInstr = nullptr;
-
- for (unsigned E = ChainInstrs.size(); ChainInstrIdx < E; ++ChainInstrIdx) {
- Instruction *ChainInstr = ChainInstrs[ChainInstrIdx];
-
- // If a barrier memory instruction was found, chain instructions that follow
- // will not be added to the valid prefix.
- if (BarrierMemoryInstr && OBB.dominates(BarrierMemoryInstr, ChainInstr))
- break;
-
- // Check (in BB order) if any instruction prevents ChainInstr from being
- // vectorized. Find and store the first such "conflicting" instruction.
- for (Instruction *MemInstr : MemoryInstrs) {
- // If a barrier memory instruction was found, do not check past it.
- if (BarrierMemoryInstr && OBB.dominates(BarrierMemoryInstr, MemInstr))
- break;
-
- auto *MemLoad = dyn_cast<LoadInst>(MemInstr);
- auto *ChainLoad = dyn_cast<LoadInst>(ChainInstr);
- if (MemLoad && ChainLoad)
- continue;
-
- // We can ignore the alias if the we have a load store pair and the load
- // is known to be invariant. The load cannot be clobbered by the store.
- auto IsInvariantLoad = [](const LoadInst *LI) -> bool {
- return LI->getMetadata(LLVMContext::MD_invariant_load);
- };
-
- // We can ignore the alias as long as the load comes before the store,
- // because that means we won't be moving the load past the store to
- // vectorize it (the vectorized load is inserted at the location of the
- // first load in the chain).
- if (isa<StoreInst>(MemInstr) && ChainLoad &&
- (IsInvariantLoad(ChainLoad) || OBB.dominates(ChainLoad, MemInstr)))
- continue;
-
- // Same case, but in reverse.
- if (MemLoad && isa<StoreInst>(ChainInstr) &&
- (IsInvariantLoad(MemLoad) || OBB.dominates(MemLoad, ChainInstr)))
- continue;
-
- if (!AA.isNoAlias(MemoryLocation::get(MemInstr),
- MemoryLocation::get(ChainInstr))) {
- LLVM_DEBUG({
- dbgs() << "LSV: Found alias:\n"
- " Aliasing instruction and pointer:\n"
- << " " << *MemInstr << '\n'
- << " " << *getLoadStorePointerOperand(MemInstr) << '\n'
- << " Aliased instruction and pointer:\n"
- << " " << *ChainInstr << '\n'
- << " " << *getLoadStorePointerOperand(ChainInstr) << '\n';
- });
- // Save this aliasing memory instruction as a barrier, but allow other
- // instructions that precede the barrier to be vectorized with this one.
- BarrierMemoryInstr = MemInstr;
- break;
- }
- }
- // Continue the search only for store chains, since vectorizing stores that
- // precede an aliasing load is valid. Conversely, vectorizing loads is valid
- // up to an aliasing store, but should not pull loads from further down in
- // the basic block.
- if (IsLoadChain && BarrierMemoryInstr) {
- // The BarrierMemoryInstr is a store that precedes ChainInstr.
- assert(OBB.dominates(BarrierMemoryInstr, ChainInstr));
- break;
- }
- }
-
- // Find the largest prefix of Chain whose elements are all in
- // ChainInstrs[0, ChainInstrIdx). This is the largest vectorizable prefix of
- // Chain. (Recall that Chain is in address order, but ChainInstrs is in BB
- // order.)
- SmallPtrSet<Instruction *, 8> VectorizableChainInstrs(
- ChainInstrs.begin(), ChainInstrs.begin() + ChainInstrIdx);
- unsigned ChainIdx = 0;
- for (unsigned ChainLen = Chain.size(); ChainIdx < ChainLen; ++ChainIdx) {
- if (!VectorizableChainInstrs.count(Chain[ChainIdx]))
- break;
- }
- return Chain.slice(0, ChainIdx);
-}
-
-static ChainID getChainID(const Value *Ptr, const DataLayout &DL) {
- const Value *ObjPtr = GetUnderlyingObject(Ptr, DL);
- if (const auto *Sel = dyn_cast<SelectInst>(ObjPtr)) {
- // The select's themselves are distinct instructions even if they share the
- // same condition and evaluate to consecutive pointers for true and false
- // values of the condition. Therefore using the select's themselves for
- // grouping instructions would put consecutive accesses into different lists
- // and they won't be even checked for being consecutive, and won't be
- // vectorized.
- return Sel->getCondition();
- }
- return ObjPtr;
-}
-
-std::pair<InstrListMap, InstrListMap>
-Vectorizer::collectInstructions(BasicBlock *BB) {
- InstrListMap LoadRefs;
- InstrListMap StoreRefs;
-
- for (Instruction &I : *BB) {
- if (!I.mayReadOrWriteMemory())
- continue;
-
- if (LoadInst *LI = dyn_cast<LoadInst>(&I)) {
- if (!LI->isSimple())
- continue;
-
- // Skip if it's not legal.
- if (!TTI.isLegalToVectorizeLoad(LI))
- continue;
-
- Type *Ty = LI->getType();
- if (!VectorType::isValidElementType(Ty->getScalarType()))
- continue;
-
- // Skip weird non-byte sizes. They probably aren't worth the effort of
- // handling correctly.
- unsigned TySize = DL.getTypeSizeInBits(Ty);
- if ((TySize % 8) != 0)
- continue;
-
- // Skip vectors of pointers. The vectorizeLoadChain/vectorizeStoreChain
- // functions are currently using an integer type for the vectorized
- // load/store, and does not support casting between the integer type and a
- // vector of pointers (e.g. i64 to <2 x i16*>)
- if (Ty->isVectorTy() && Ty->isPtrOrPtrVectorTy())
- continue;
-
- Value *Ptr = LI->getPointerOperand();
- unsigned AS = Ptr->getType()->getPointerAddressSpace();
- unsigned VecRegSize = TTI.getLoadStoreVecRegBitWidth(AS);
-
- unsigned VF = VecRegSize / TySize;
- VectorType *VecTy = dyn_cast<VectorType>(Ty);
-
- // No point in looking at these if they're too big to vectorize.
- if (TySize > VecRegSize / 2 ||
- (VecTy && TTI.getLoadVectorFactor(VF, TySize, TySize / 8, VecTy) == 0))
- continue;
-
- // Make sure all the users of a vector are constant-index extracts.
- if (isa<VectorType>(Ty) && !llvm::all_of(LI->users(), [](const User *U) {
- const ExtractElementInst *EEI = dyn_cast<ExtractElementInst>(U);
- return EEI && isa<ConstantInt>(EEI->getOperand(1));
- }))
- continue;
-
- // Save the load locations.
- const ChainID ID = getChainID(Ptr, DL);
- LoadRefs[ID].push_back(LI);
- } else if (StoreInst *SI = dyn_cast<StoreInst>(&I)) {
- if (!SI->isSimple())
- continue;
-
- // Skip if it's not legal.
- if (!TTI.isLegalToVectorizeStore(SI))
- continue;
-
- Type *Ty = SI->getValueOperand()->getType();
- if (!VectorType::isValidElementType(Ty->getScalarType()))
- continue;
-
- // Skip vectors of pointers. The vectorizeLoadChain/vectorizeStoreChain
- // functions are currently using an integer type for the vectorized
- // load/store, and does not support casting between the integer type and a
- // vector of pointers (e.g. i64 to <2 x i16*>)
- if (Ty->isVectorTy() && Ty->isPtrOrPtrVectorTy())
- continue;
-
- // Skip weird non-byte sizes. They probably aren't worth the effort of
- // handling correctly.
- unsigned TySize = DL.getTypeSizeInBits(Ty);
- if ((TySize % 8) != 0)
- continue;
-
- Value *Ptr = SI->getPointerOperand();
- unsigned AS = Ptr->getType()->getPointerAddressSpace();
- unsigned VecRegSize = TTI.getLoadStoreVecRegBitWidth(AS);
-
- unsigned VF = VecRegSize / TySize;
- VectorType *VecTy = dyn_cast<VectorType>(Ty);
-
- // No point in looking at these if they're too big to vectorize.
- if (TySize > VecRegSize / 2 ||
- (VecTy && TTI.getStoreVectorFactor(VF, TySize, TySize / 8, VecTy) == 0))
- continue;
-
- if (isa<VectorType>(Ty) && !llvm::all_of(SI->users(), [](const User *U) {
- const ExtractElementInst *EEI = dyn_cast<ExtractElementInst>(U);
- return EEI && isa<ConstantInt>(EEI->getOperand(1));
- }))
- continue;
-
- // Save store location.
- const ChainID ID = getChainID(Ptr, DL);
- StoreRefs[ID].push_back(SI);
- }
- }
-
- return {LoadRefs, StoreRefs};
-}
-
-bool Vectorizer::vectorizeChains(InstrListMap &Map) {
- bool Changed = false;
-
- for (const std::pair<ChainID, InstrList> &Chain : Map) {
- unsigned Size = Chain.second.size();
- if (Size < 2)
- continue;
-
- LLVM_DEBUG(dbgs() << "LSV: Analyzing a chain of length " << Size << ".\n");
-
- // Process the stores in chunks of 64.
- for (unsigned CI = 0, CE = Size; CI < CE; CI += 64) {
- unsigned Len = std::min<unsigned>(CE - CI, 64);
- ArrayRef<Instruction *> Chunk(&Chain.second[CI], Len);
- Changed |= vectorizeInstructions(Chunk);
- }
- }
-
- return Changed;
-}
-
-bool Vectorizer::vectorizeInstructions(ArrayRef<Instruction *> Instrs) {
- LLVM_DEBUG(dbgs() << "LSV: Vectorizing " << Instrs.size()
- << " instructions.\n");
- SmallVector<int, 16> Heads, Tails;
- int ConsecutiveChain[64];
-
- // Do a quadratic search on all of the given loads/stores and find all of the
- // pairs of loads/stores that follow each other.
- for (int i = 0, e = Instrs.size(); i < e; ++i) {
- ConsecutiveChain[i] = -1;
- for (int j = e - 1; j >= 0; --j) {
- if (i == j)
- continue;
-
- if (isConsecutiveAccess(Instrs[i], Instrs[j])) {
- if (ConsecutiveChain[i] != -1) {
- int CurDistance = std::abs(ConsecutiveChain[i] - i);
- int NewDistance = std::abs(ConsecutiveChain[i] - j);
- if (j < i || NewDistance > CurDistance)
- continue; // Should not insert.
- }
-
- Tails.push_back(j);
- Heads.push_back(i);
- ConsecutiveChain[i] = j;
- }
- }
- }
-
- bool Changed = false;
- SmallPtrSet<Instruction *, 16> InstructionsProcessed;
-
- for (int Head : Heads) {
- if (InstructionsProcessed.count(Instrs[Head]))
- continue;
- bool LongerChainExists = false;
- for (unsigned TIt = 0; TIt < Tails.size(); TIt++)
- if (Head == Tails[TIt] &&
- !InstructionsProcessed.count(Instrs[Heads[TIt]])) {
- LongerChainExists = true;
- break;
- }
- if (LongerChainExists)
- continue;
-
- // We found an instr that starts a chain. Now follow the chain and try to
- // vectorize it.
- SmallVector<Instruction *, 16> Operands;
- int I = Head;
- while (I != -1 && (is_contained(Tails, I) || is_contained(Heads, I))) {
- if (InstructionsProcessed.count(Instrs[I]))
- break;
-
- Operands.push_back(Instrs[I]);
- I = ConsecutiveChain[I];
- }
-
- bool Vectorized = false;
- if (isa<LoadInst>(*Operands.begin()))
- Vectorized = vectorizeLoadChain(Operands, &InstructionsProcessed);
- else
- Vectorized = vectorizeStoreChain(Operands, &InstructionsProcessed);
-
- Changed |= Vectorized;
- }
-
- return Changed;
-}
-
-bool Vectorizer::vectorizeStoreChain(
- ArrayRef<Instruction *> Chain,
- SmallPtrSet<Instruction *, 16> *InstructionsProcessed) {
- StoreInst *S0 = cast<StoreInst>(Chain[0]);
-
- // If the vector has an int element, default to int for the whole store.
- Type *StoreTy = nullptr;
- for (Instruction *I : Chain) {
- StoreTy = cast<StoreInst>(I)->getValueOperand()->getType();
- if (StoreTy->isIntOrIntVectorTy())
- break;
-
- if (StoreTy->isPtrOrPtrVectorTy()) {
- StoreTy = Type::getIntNTy(F.getParent()->getContext(),
- DL.getTypeSizeInBits(StoreTy));
- break;
- }
- }
- assert(StoreTy && "Failed to find store type");
-
- unsigned Sz = DL.getTypeSizeInBits(StoreTy);
- unsigned AS = S0->getPointerAddressSpace();
- unsigned VecRegSize = TTI.getLoadStoreVecRegBitWidth(AS);
- unsigned VF = VecRegSize / Sz;
- unsigned ChainSize = Chain.size();
- unsigned Alignment = getAlignment(S0);
-
- if (!isPowerOf2_32(Sz) || VF < 2 || ChainSize < 2) {
- InstructionsProcessed->insert(Chain.begin(), Chain.end());
- return false;
- }
-
- ArrayRef<Instruction *> NewChain = getVectorizablePrefix(Chain);
- if (NewChain.empty()) {
- // No vectorization possible.
- InstructionsProcessed->insert(Chain.begin(), Chain.end());
- return false;
- }
- if (NewChain.size() == 1) {
- // Failed after the first instruction. Discard it and try the smaller chain.
- InstructionsProcessed->insert(NewChain.front());
- return false;
- }
-
- // Update Chain to the valid vectorizable subchain.
- Chain = NewChain;
- ChainSize = Chain.size();
-
- // Check if it's legal to vectorize this chain. If not, split the chain and
- // try again.
- unsigned EltSzInBytes = Sz / 8;
- unsigned SzInBytes = EltSzInBytes * ChainSize;
-
- VectorType *VecTy;
- VectorType *VecStoreTy = dyn_cast<VectorType>(StoreTy);
- if (VecStoreTy)
- VecTy = VectorType::get(StoreTy->getScalarType(),
- Chain.size() * VecStoreTy->getNumElements());
- else
- VecTy = VectorType::get(StoreTy, Chain.size());
-
- // If it's more than the max vector size or the target has a better
- // vector factor, break it into two pieces.
- unsigned TargetVF = TTI.getStoreVectorFactor(VF, Sz, SzInBytes, VecTy);
- if (ChainSize > VF || (VF != TargetVF && TargetVF < ChainSize)) {
- LLVM_DEBUG(dbgs() << "LSV: Chain doesn't match with the vector factor."
- " Creating two separate arrays.\n");
- return vectorizeStoreChain(Chain.slice(0, TargetVF),
- InstructionsProcessed) |
- vectorizeStoreChain(Chain.slice(TargetVF), InstructionsProcessed);
- }
-
- LLVM_DEBUG({
- dbgs() << "LSV: Stores to vectorize:\n";
- for (Instruction *I : Chain)
- dbgs() << " " << *I << "\n";
- });
-
- // We won't try again to vectorize the elements of the chain, regardless of
- // whether we succeed below.
- InstructionsProcessed->insert(Chain.begin(), Chain.end());
-
- // If the store is going to be misaligned, don't vectorize it.
- if (accessIsMisaligned(SzInBytes, AS, Alignment)) {
- if (S0->getPointerAddressSpace() != DL.getAllocaAddrSpace()) {
- auto Chains = splitOddVectorElts(Chain, Sz);
- return vectorizeStoreChain(Chains.first, InstructionsProcessed) |
- vectorizeStoreChain(Chains.second, InstructionsProcessed);
- }
-
- unsigned NewAlign = getOrEnforceKnownAlignment(S0->getPointerOperand(),
- StackAdjustedAlignment,
- DL, S0, nullptr, &DT);
- if (NewAlign != 0)
- Alignment = NewAlign;
- }
-
- if (!TTI.isLegalToVectorizeStoreChain(SzInBytes, Alignment, AS)) {
- auto Chains = splitOddVectorElts(Chain, Sz);
- return vectorizeStoreChain(Chains.first, InstructionsProcessed) |
- vectorizeStoreChain(Chains.second, InstructionsProcessed);
- }
-
- BasicBlock::iterator First, Last;
- std::tie(First, Last) = getBoundaryInstrs(Chain);
- Builder.SetInsertPoint(&*Last);
-
- Value *Vec = UndefValue::get(VecTy);
-
- if (VecStoreTy) {
- unsigned VecWidth = VecStoreTy->getNumElements();
- for (unsigned I = 0, E = Chain.size(); I != E; ++I) {
- StoreInst *Store = cast<StoreInst>(Chain[I]);
- for (unsigned J = 0, NE = VecStoreTy->getNumElements(); J != NE; ++J) {
- unsigned NewIdx = J + I * VecWidth;
- Value *Extract = Builder.CreateExtractElement(Store->getValueOperand(),
- Builder.getInt32(J));
- if (Extract->getType() != StoreTy->getScalarType())
- Extract = Builder.CreateBitCast(Extract, StoreTy->getScalarType());
-
- Value *Insert =
- Builder.CreateInsertElement(Vec, Extract, Builder.getInt32(NewIdx));
- Vec = Insert;
- }
- }
- } else {
- for (unsigned I = 0, E = Chain.size(); I != E; ++I) {
- StoreInst *Store = cast<StoreInst>(Chain[I]);
- Value *Extract = Store->getValueOperand();
- if (Extract->getType() != StoreTy->getScalarType())
- Extract =
- Builder.CreateBitOrPointerCast(Extract, StoreTy->getScalarType());
-
- Value *Insert =
- Builder.CreateInsertElement(Vec, Extract, Builder.getInt32(I));
- Vec = Insert;
- }
- }
-
- StoreInst *SI = Builder.CreateAlignedStore(
- Vec,
- Builder.CreateBitCast(S0->getPointerOperand(), VecTy->getPointerTo(AS)),
- Alignment);
- propagateMetadata(SI, Chain);
-
- eraseInstructions(Chain);
- ++NumVectorInstructions;
- NumScalarsVectorized += Chain.size();
- return true;
-}
-
-bool Vectorizer::vectorizeLoadChain(
- ArrayRef<Instruction *> Chain,
- SmallPtrSet<Instruction *, 16> *InstructionsProcessed) {
- LoadInst *L0 = cast<LoadInst>(Chain[0]);
-
- // If the vector has an int element, default to int for the whole load.
- Type *LoadTy;
- for (const auto &V : Chain) {
- LoadTy = cast<LoadInst>(V)->getType();
- if (LoadTy->isIntOrIntVectorTy())
- break;
-
- if (LoadTy->isPtrOrPtrVectorTy()) {
- LoadTy = Type::getIntNTy(F.getParent()->getContext(),
- DL.getTypeSizeInBits(LoadTy));
- break;
- }
- }
-
- unsigned Sz = DL.getTypeSizeInBits(LoadTy);
- unsigned AS = L0->getPointerAddressSpace();
- unsigned VecRegSize = TTI.getLoadStoreVecRegBitWidth(AS);
- unsigned VF = VecRegSize / Sz;
- unsigned ChainSize = Chain.size();
- unsigned Alignment = getAlignment(L0);
-
- if (!isPowerOf2_32(Sz) || VF < 2 || ChainSize < 2) {
- InstructionsProcessed->insert(Chain.begin(), Chain.end());
- return false;
- }
-
- ArrayRef<Instruction *> NewChain = getVectorizablePrefix(Chain);
- if (NewChain.empty()) {
- // No vectorization possible.
- InstructionsProcessed->insert(Chain.begin(), Chain.end());
- return false;
- }
- if (NewChain.size() == 1) {
- // Failed after the first instruction. Discard it and try the smaller chain.
- InstructionsProcessed->insert(NewChain.front());
- return false;
- }
-
- // Update Chain to the valid vectorizable subchain.
- Chain = NewChain;
- ChainSize = Chain.size();
-
- // Check if it's legal to vectorize this chain. If not, split the chain and
- // try again.
- unsigned EltSzInBytes = Sz / 8;
- unsigned SzInBytes = EltSzInBytes * ChainSize;
- VectorType *VecTy;
- VectorType *VecLoadTy = dyn_cast<VectorType>(LoadTy);
- if (VecLoadTy)
- VecTy = VectorType::get(LoadTy->getScalarType(),
- Chain.size() * VecLoadTy->getNumElements());
- else
- VecTy = VectorType::get(LoadTy, Chain.size());
-
- // If it's more than the max vector size or the target has a better
- // vector factor, break it into two pieces.
- unsigned TargetVF = TTI.getLoadVectorFactor(VF, Sz, SzInBytes, VecTy);
- if (ChainSize > VF || (VF != TargetVF && TargetVF < ChainSize)) {
- LLVM_DEBUG(dbgs() << "LSV: Chain doesn't match with the vector factor."
- " Creating two separate arrays.\n");
- return vectorizeLoadChain(Chain.slice(0, TargetVF), InstructionsProcessed) |
- vectorizeLoadChain(Chain.slice(TargetVF), InstructionsProcessed);
- }
-
- // We won't try again to vectorize the elements of the chain, regardless of
- // whether we succeed below.
- InstructionsProcessed->insert(Chain.begin(), Chain.end());
-
- // If the load is going to be misaligned, don't vectorize it.
- if (accessIsMisaligned(SzInBytes, AS, Alignment)) {
- if (L0->getPointerAddressSpace() != DL.getAllocaAddrSpace()) {
- auto Chains = splitOddVectorElts(Chain, Sz);
- return vectorizeLoadChain(Chains.first, InstructionsProcessed) |
- vectorizeLoadChain(Chains.second, InstructionsProcessed);
- }
-
- Alignment = getOrEnforceKnownAlignment(
- L0->getPointerOperand(), StackAdjustedAlignment, DL, L0, nullptr, &DT);
- }
-
- if (!TTI.isLegalToVectorizeLoadChain(SzInBytes, Alignment, AS)) {
- auto Chains = splitOddVectorElts(Chain, Sz);
- return vectorizeLoadChain(Chains.first, InstructionsProcessed) |
- vectorizeLoadChain(Chains.second, InstructionsProcessed);
- }
-
- LLVM_DEBUG({
- dbgs() << "LSV: Loads to vectorize:\n";
- for (Instruction *I : Chain)
- I->dump();
- });
-
- // getVectorizablePrefix already computed getBoundaryInstrs. The value of
- // Last may have changed since then, but the value of First won't have. If it
- // matters, we could compute getBoundaryInstrs only once and reuse it here.
- BasicBlock::iterator First, Last;
- std::tie(First, Last) = getBoundaryInstrs(Chain);
- Builder.SetInsertPoint(&*First);
-
- Value *Bitcast =
- Builder.CreateBitCast(L0->getPointerOperand(), VecTy->getPointerTo(AS));
- LoadInst *LI = Builder.CreateAlignedLoad(VecTy, Bitcast, Alignment);
- propagateMetadata(LI, Chain);
-
- if (VecLoadTy) {
- SmallVector<Instruction *, 16> InstrsToErase;
-
- unsigned VecWidth = VecLoadTy->getNumElements();
- for (unsigned I = 0, E = Chain.size(); I != E; ++I) {
- for (auto Use : Chain[I]->users()) {
- // All users of vector loads are ExtractElement instructions with
- // constant indices, otherwise we would have bailed before now.
- Instruction *UI = cast<Instruction>(Use);
- unsigned Idx = cast<ConstantInt>(UI->getOperand(1))->getZExtValue();
- unsigned NewIdx = Idx + I * VecWidth;
- Value *V = Builder.CreateExtractElement(LI, Builder.getInt32(NewIdx),
- UI->getName());
- if (V->getType() != UI->getType())
- V = Builder.CreateBitCast(V, UI->getType());
-
- // Replace the old instruction.
- UI->replaceAllUsesWith(V);
- InstrsToErase.push_back(UI);
- }
- }
-
- // Bitcast might not be an Instruction, if the value being loaded is a
- // constant. In that case, no need to reorder anything.
- if (Instruction *BitcastInst = dyn_cast<Instruction>(Bitcast))
- reorder(BitcastInst);
-
- for (auto I : InstrsToErase)
- I->eraseFromParent();
- } else {
- for (unsigned I = 0, E = Chain.size(); I != E; ++I) {
- Value *CV = Chain[I];
- Value *V =
- Builder.CreateExtractElement(LI, Builder.getInt32(I), CV->getName());
- if (V->getType() != CV->getType()) {
- V = Builder.CreateBitOrPointerCast(V, CV->getType());
- }
-
- // Replace the old instruction.
- CV->replaceAllUsesWith(V);
- }
-
- if (Instruction *BitcastInst = dyn_cast<Instruction>(Bitcast))
- reorder(BitcastInst);
- }
-
- eraseInstructions(Chain);
-
- ++NumVectorInstructions;
- NumScalarsVectorized += Chain.size();
- return true;
-}
-
-bool Vectorizer::accessIsMisaligned(unsigned SzInBytes, unsigned AddressSpace,
- unsigned Alignment) {
- if (Alignment % SzInBytes == 0)
- return false;
-
- bool Fast = false;
- bool Allows = TTI.allowsMisalignedMemoryAccesses(F.getParent()->getContext(),
- SzInBytes * 8, AddressSpace,
- Alignment, &Fast);
- LLVM_DEBUG(dbgs() << "LSV: Target said misaligned is allowed? " << Allows
- << " and fast? " << Fast << "\n";);
- return !Allows || !Fast;
-}