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HexagonVectorCombine.cpp
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HexagonVectorCombine.cpp
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//===-- HexagonVectorCombine.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
//
//===----------------------------------------------------------------------===//
// HexagonVectorCombine is a utility class implementing a variety of functions
// that assist in vector-based optimizations.
//
// AlignVectors: replace unaligned vector loads and stores with aligned ones.
//===----------------------------------------------------------------------===//
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicsHexagon.h"
#include "llvm/IR/Metadata.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "HexagonSubtarget.h"
#include "HexagonTargetMachine.h"
#include <algorithm>
#include <deque>
#include <map>
#include <set>
#include <utility>
#include <vector>
#define DEBUG_TYPE "hexagon-vc"
using namespace llvm;
namespace {
class HexagonVectorCombine {
public:
HexagonVectorCombine(Function &F_, AliasAnalysis &AA_, AssumptionCache &AC_,
DominatorTree &DT_, TargetLibraryInfo &TLI_,
const TargetMachine &TM_)
: F(F_), DL(F.getParent()->getDataLayout()), AA(AA_), AC(AC_), DT(DT_),
TLI(TLI_),
HST(static_cast<const HexagonSubtarget &>(*TM_.getSubtargetImpl(F))) {}
bool run();
// Common integer type.
IntegerType *getIntTy() const;
// Byte type: either scalar (when Length = 0), or vector with given
// element count.
Type *getByteTy(int ElemCount = 0) const;
// Boolean type: either scalar (when Length = 0), or vector with given
// element count.
Type *getBoolTy(int ElemCount = 0) const;
// Create a ConstantInt of type returned by getIntTy with the value Val.
ConstantInt *getConstInt(int Val) const;
// Get the integer value of V, if it exists.
Optional<APInt> getIntValue(const Value *Val) const;
// Is V a constant 0, or a vector of 0s?
bool isZero(const Value *Val) const;
// Is V an undef value?
bool isUndef(const Value *Val) const;
int getSizeOf(const Value *Val) const;
int getSizeOf(const Type *Ty) const;
int getAllocSizeOf(const Type *Ty) const;
int getTypeAlignment(Type *Ty) const;
VectorType *getByteVectorTy(int ScLen) const;
Constant *getNullValue(Type *Ty) const;
Constant *getFullValue(Type *Ty) const;
Value *insertb(IRBuilder<> &Builder, Value *Dest, Value *Src, int Start,
int Length, int Where) const;
Value *vlalignb(IRBuilder<> &Builder, Value *Lo, Value *Hi, Value *Amt) const;
Value *vralignb(IRBuilder<> &Builder, Value *Lo, Value *Hi, Value *Amt) const;
Value *concat(IRBuilder<> &Builder, ArrayRef<Value *> Vecs) const;
Value *vresize(IRBuilder<> &Builder, Value *Val, int NewSize,
Value *Pad) const;
Value *rescale(IRBuilder<> &Builder, Value *Mask, Type *FromTy,
Type *ToTy) const;
Value *vlsb(IRBuilder<> &Builder, Value *Val) const;
Value *vbytes(IRBuilder<> &Builder, Value *Val) const;
Value *createHvxIntrinsic(IRBuilder<> &Builder, Intrinsic::ID IntID,
Type *RetTy, ArrayRef<Value *> Args) const;
Optional<int> calculatePointerDifference(Value *Ptr0, Value *Ptr1) const;
template <typename T = std::vector<Instruction *>>
bool isSafeToMoveBeforeInBB(const Instruction &In,
BasicBlock::const_iterator To,
const T &Ignore = {}) const;
Function &F;
const DataLayout &DL;
AliasAnalysis &AA;
AssumptionCache &AC;
DominatorTree &DT;
TargetLibraryInfo &TLI;
const HexagonSubtarget &HST;
private:
#ifndef NDEBUG
// These two functions are only used for assertions at the moment.
bool isByteVecTy(Type *Ty) const;
bool isSectorTy(Type *Ty) const;
#endif
Value *getElementRange(IRBuilder<> &Builder, Value *Lo, Value *Hi, int Start,
int Length) const;
};
class AlignVectors {
public:
AlignVectors(HexagonVectorCombine &HVC_) : HVC(HVC_) {}
bool run();
private:
using InstList = std::vector<Instruction *>;
struct Segment {
void *Data;
int Start;
int Size;
};
struct AddrInfo {
AddrInfo(const AddrInfo &) = default;
AddrInfo(const HexagonVectorCombine &HVC, Instruction *I, Value *A, Type *T,
Align H)
: Inst(I), Addr(A), ValTy(T), HaveAlign(H),
NeedAlign(HVC.getTypeAlignment(ValTy)) {}
// XXX: add Size member?
Instruction *Inst;
Value *Addr;
Type *ValTy;
Align HaveAlign;
Align NeedAlign;
int Offset = 0; // Offset (in bytes) from the first member of the
// containing AddrList.
};
using AddrList = std::vector<AddrInfo>;
struct InstrLess {
bool operator()(const Instruction *A, const Instruction *B) const {
return A->comesBefore(B);
}
};
using DepList = std::set<Instruction *, InstrLess>;
struct MoveGroup {
MoveGroup(const AddrInfo &AI, Instruction *B, bool Hvx, bool Load)
: Base(B), Main{AI.Inst}, IsHvx(Hvx), IsLoad(Load) {}
Instruction *Base; // Base instruction of the parent address group.
InstList Main; // Main group of instructions.
InstList Deps; // List of dependencies.
bool IsHvx; // Is this group of HVX instructions?
bool IsLoad; // Is this a load group?
};
using MoveList = std::vector<MoveGroup>;
struct ByteSpan {
struct Segment {
// Segment of a Value: 'Len' bytes starting at byte 'Begin'.
Segment(Value *Val, int Begin, int Len)
: Val(Val), Start(Begin), Size(Len) {}
Segment(const Segment &Seg) = default;
Value *Val; // Value representable as a sequence of bytes.
int Start; // First byte of the value that belongs to the segment.
int Size; // Number of bytes in the segment.
};
struct Block {
Block(Value *Val, int Len, int Pos) : Seg(Val, 0, Len), Pos(Pos) {}
Block(Value *Val, int Off, int Len, int Pos)
: Seg(Val, Off, Len), Pos(Pos) {}
Block(const Block &Blk) = default;
Segment Seg; // Value segment.
int Pos; // Position (offset) of the segment in the Block.
};
int extent() const;
ByteSpan section(int Start, int Length) const;
ByteSpan &shift(int Offset);
SmallVector<Value *, 8> values() const;
int size() const { return Blocks.size(); }
Block &operator[](int i) { return Blocks[i]; }
std::vector<Block> Blocks;
using iterator = decltype(Blocks)::iterator;
iterator begin() { return Blocks.begin(); }
iterator end() { return Blocks.end(); }
using const_iterator = decltype(Blocks)::const_iterator;
const_iterator begin() const { return Blocks.begin(); }
const_iterator end() const { return Blocks.end(); }
};
Align getAlignFromValue(const Value *V) const;
Optional<MemoryLocation> getLocation(const Instruction &In) const;
Optional<AddrInfo> getAddrInfo(Instruction &In) const;
bool isHvx(const AddrInfo &AI) const;
Value *getPayload(Value *Val) const;
Value *getMask(Value *Val) const;
Value *getPassThrough(Value *Val) const;
Value *createAdjustedPointer(IRBuilder<> &Builder, Value *Ptr, Type *ValTy,
int Adjust) const;
Value *createAlignedPointer(IRBuilder<> &Builder, Value *Ptr, Type *ValTy,
int Alignment) const;
Value *createAlignedLoad(IRBuilder<> &Builder, Type *ValTy, Value *Ptr,
int Alignment, Value *Mask, Value *PassThru) const;
Value *createAlignedStore(IRBuilder<> &Builder, Value *Val, Value *Ptr,
int Alignment, Value *Mask) const;
bool createAddressGroups();
MoveList createLoadGroups(const AddrList &Group) const;
MoveList createStoreGroups(const AddrList &Group) const;
bool move(const MoveGroup &Move) const;
bool realignGroup(const MoveGroup &Move) const;
friend raw_ostream &operator<<(raw_ostream &OS, const AddrInfo &AI);
friend raw_ostream &operator<<(raw_ostream &OS, const MoveGroup &MG);
friend raw_ostream &operator<<(raw_ostream &OS, const ByteSpan &BS);
std::map<Instruction *, AddrList> AddrGroups;
HexagonVectorCombine &HVC;
};
LLVM_ATTRIBUTE_UNUSED
raw_ostream &operator<<(raw_ostream &OS, const AlignVectors::AddrInfo &AI) {
OS << "Inst: " << AI.Inst << " " << *AI.Inst << '\n';
OS << "Addr: " << *AI.Addr << '\n';
OS << "Type: " << *AI.ValTy << '\n';
OS << "HaveAlign: " << AI.HaveAlign.value() << '\n';
OS << "NeedAlign: " << AI.NeedAlign.value() << '\n';
OS << "Offset: " << AI.Offset;
return OS;
}
LLVM_ATTRIBUTE_UNUSED
raw_ostream &operator<<(raw_ostream &OS, const AlignVectors::MoveGroup &MG) {
OS << "Main\n";
for (Instruction *I : MG.Main)
OS << " " << *I << '\n';
OS << "Deps\n";
for (Instruction *I : MG.Deps)
OS << " " << *I << '\n';
return OS;
}
LLVM_ATTRIBUTE_UNUSED
raw_ostream &operator<<(raw_ostream &OS, const AlignVectors::ByteSpan &BS) {
OS << "ByteSpan[size=" << BS.size() << ", extent=" << BS.extent() << '\n';
for (const AlignVectors::ByteSpan::Block &B : BS) {
OS << " @" << B.Pos << " [" << B.Seg.Start << ',' << B.Seg.Size << "] "
<< *B.Seg.Val << '\n';
}
OS << ']';
return OS;
}
} // namespace
namespace {
template <typename T> T *getIfUnordered(T *MaybeT) {
return MaybeT && MaybeT->isUnordered() ? MaybeT : nullptr;
}
template <typename T> T *isCandidate(Instruction *In) {
return dyn_cast<T>(In);
}
template <> LoadInst *isCandidate<LoadInst>(Instruction *In) {
return getIfUnordered(dyn_cast<LoadInst>(In));
}
template <> StoreInst *isCandidate<StoreInst>(Instruction *In) {
return getIfUnordered(dyn_cast<StoreInst>(In));
}
#if !defined(_MSC_VER) || _MSC_VER >= 1926
// VS2017 and some versions of VS2019 have trouble compiling this:
// error C2976: 'std::map': too few template arguments
// VS 2019 16.x is known to work, except for 16.4/16.5 (MSC_VER 1924/1925)
template <typename Pred, typename... Ts>
void erase_if(std::map<Ts...> &map, Pred p)
#else
template <typename Pred, typename T, typename U>
void erase_if(std::map<T, U> &map, Pred p)
#endif
{
for (auto i = map.begin(), e = map.end(); i != e;) {
if (p(*i))
i = map.erase(i);
else
i = std::next(i);
}
}
// Forward other erase_ifs to the LLVM implementations.
template <typename Pred, typename T> void erase_if(T &&container, Pred p) {
llvm::erase_if(std::forward<T>(container), p);
}
} // namespace
// --- Begin AlignVectors
auto AlignVectors::ByteSpan::extent() const -> int {
if (size() == 0)
return 0;
int Min = Blocks[0].Pos;
int Max = Blocks[0].Pos + Blocks[0].Seg.Size;
for (int i = 1, e = size(); i != e; ++i) {
Min = std::min(Min, Blocks[i].Pos);
Max = std::max(Max, Blocks[i].Pos + Blocks[i].Seg.Size);
}
return Max - Min;
}
auto AlignVectors::ByteSpan::section(int Start, int Length) const -> ByteSpan {
ByteSpan Section;
for (const ByteSpan::Block &B : Blocks) {
int L = std::max(B.Pos, Start); // Left end.
int R = std::min(B.Pos + B.Seg.Size, Start + Length); // Right end+1.
if (L < R) {
// How much to chop off the beginning of the segment:
int Off = L > B.Pos ? L - B.Pos : 0;
Section.Blocks.emplace_back(B.Seg.Val, B.Seg.Start + Off, R - L, L);
}
}
return Section;
}
auto AlignVectors::ByteSpan::shift(int Offset) -> ByteSpan & {
for (Block &B : Blocks)
B.Pos += Offset;
return *this;
}
auto AlignVectors::ByteSpan::values() const -> SmallVector<Value *, 8> {
SmallVector<Value *, 8> Values(Blocks.size());
for (int i = 0, e = Blocks.size(); i != e; ++i)
Values[i] = Blocks[i].Seg.Val;
return Values;
}
auto AlignVectors::getAlignFromValue(const Value *V) const -> Align {
const auto *C = dyn_cast<ConstantInt>(V);
assert(C && "Alignment must be a compile-time constant integer");
return C->getAlignValue();
}
auto AlignVectors::getAddrInfo(Instruction &In) const -> Optional<AddrInfo> {
if (auto *L = isCandidate<LoadInst>(&In))
return AddrInfo(HVC, L, L->getPointerOperand(), L->getType(),
L->getAlign());
if (auto *S = isCandidate<StoreInst>(&In))
return AddrInfo(HVC, S, S->getPointerOperand(),
S->getValueOperand()->getType(), S->getAlign());
if (auto *II = isCandidate<IntrinsicInst>(&In)) {
Intrinsic::ID ID = II->getIntrinsicID();
switch (ID) {
case Intrinsic::masked_load:
return AddrInfo(HVC, II, II->getArgOperand(0), II->getType(),
getAlignFromValue(II->getArgOperand(1)));
case Intrinsic::masked_store:
return AddrInfo(HVC, II, II->getArgOperand(1),
II->getArgOperand(0)->getType(),
getAlignFromValue(II->getArgOperand(2)));
}
}
return Optional<AddrInfo>();
}
auto AlignVectors::isHvx(const AddrInfo &AI) const -> bool {
return HVC.HST.isTypeForHVX(AI.ValTy);
}
auto AlignVectors::getPayload(Value *Val) const -> Value * {
if (auto *In = dyn_cast<Instruction>(Val)) {
Intrinsic::ID ID = 0;
if (auto *II = dyn_cast<IntrinsicInst>(In))
ID = II->getIntrinsicID();
if (isa<StoreInst>(In) || ID == Intrinsic::masked_store)
return In->getOperand(0);
}
return Val;
}
auto AlignVectors::getMask(Value *Val) const -> Value * {
if (auto *II = dyn_cast<IntrinsicInst>(Val)) {
switch (II->getIntrinsicID()) {
case Intrinsic::masked_load:
return II->getArgOperand(2);
case Intrinsic::masked_store:
return II->getArgOperand(3);
}
}
Type *ValTy = getPayload(Val)->getType();
if (auto *VecTy = dyn_cast<VectorType>(ValTy)) {
int ElemCount = VecTy->getElementCount().getFixedValue();
return HVC.getFullValue(HVC.getBoolTy(ElemCount));
}
return HVC.getFullValue(HVC.getBoolTy());
}
auto AlignVectors::getPassThrough(Value *Val) const -> Value * {
if (auto *II = dyn_cast<IntrinsicInst>(Val)) {
if (II->getIntrinsicID() == Intrinsic::masked_load)
return II->getArgOperand(3);
}
return UndefValue::get(getPayload(Val)->getType());
}
auto AlignVectors::createAdjustedPointer(IRBuilder<> &Builder, Value *Ptr,
Type *ValTy, int Adjust) const
-> Value * {
// The adjustment is in bytes, but if it's a multiple of the type size,
// we don't need to do pointer casts.
auto *PtrTy = cast<PointerType>(Ptr->getType());
if (!PtrTy->isOpaque()) {
Type *ElemTy = PtrTy->getElementType();
int ElemSize = HVC.getAllocSizeOf(ElemTy);
if (Adjust % ElemSize == 0 && Adjust != 0) {
Value *Tmp0 =
Builder.CreateGEP(ElemTy, Ptr, HVC.getConstInt(Adjust / ElemSize));
return Builder.CreatePointerCast(Tmp0, ValTy->getPointerTo());
}
}
PointerType *CharPtrTy = Type::getInt8PtrTy(HVC.F.getContext());
Value *Tmp0 = Builder.CreatePointerCast(Ptr, CharPtrTy);
Value *Tmp1 = Builder.CreateGEP(Type::getInt8Ty(HVC.F.getContext()), Tmp0,
HVC.getConstInt(Adjust));
return Builder.CreatePointerCast(Tmp1, ValTy->getPointerTo());
}
auto AlignVectors::createAlignedPointer(IRBuilder<> &Builder, Value *Ptr,
Type *ValTy, int Alignment) const
-> Value * {
Value *AsInt = Builder.CreatePtrToInt(Ptr, HVC.getIntTy());
Value *Mask = HVC.getConstInt(-Alignment);
Value *And = Builder.CreateAnd(AsInt, Mask);
return Builder.CreateIntToPtr(And, ValTy->getPointerTo());
}
auto AlignVectors::createAlignedLoad(IRBuilder<> &Builder, Type *ValTy,
Value *Ptr, int Alignment, Value *Mask,
Value *PassThru) const -> Value * {
assert(!HVC.isUndef(Mask)); // Should this be allowed?
if (HVC.isZero(Mask))
return PassThru;
if (Mask == ConstantInt::getTrue(Mask->getType()))
return Builder.CreateAlignedLoad(ValTy, Ptr, Align(Alignment));
return Builder.CreateMaskedLoad(ValTy, Ptr, Align(Alignment), Mask, PassThru);
}
auto AlignVectors::createAlignedStore(IRBuilder<> &Builder, Value *Val,
Value *Ptr, int Alignment,
Value *Mask) const -> Value * {
if (HVC.isZero(Mask) || HVC.isUndef(Val) || HVC.isUndef(Mask))
return UndefValue::get(Val->getType());
if (Mask == ConstantInt::getTrue(Mask->getType()))
return Builder.CreateAlignedStore(Val, Ptr, Align(Alignment));
return Builder.CreateMaskedStore(Val, Ptr, Align(Alignment), Mask);
}
auto AlignVectors::createAddressGroups() -> bool {
// An address group created here may contain instructions spanning
// multiple basic blocks.
AddrList WorkStack;
auto findBaseAndOffset = [&](AddrInfo &AI) -> std::pair<Instruction *, int> {
for (AddrInfo &W : WorkStack) {
if (auto D = HVC.calculatePointerDifference(AI.Addr, W.Addr))
return std::make_pair(W.Inst, *D);
}
return std::make_pair(nullptr, 0);
};
auto traverseBlock = [&](DomTreeNode *DomN, auto Visit) -> void {
BasicBlock &Block = *DomN->getBlock();
for (Instruction &I : Block) {
auto AI = this->getAddrInfo(I); // Use this-> for gcc6.
if (!AI)
continue;
auto F = findBaseAndOffset(*AI);
Instruction *GroupInst;
if (Instruction *BI = F.first) {
AI->Offset = F.second;
GroupInst = BI;
} else {
WorkStack.push_back(*AI);
GroupInst = AI->Inst;
}
AddrGroups[GroupInst].push_back(*AI);
}
for (DomTreeNode *C : DomN->children())
Visit(C, Visit);
while (!WorkStack.empty() && WorkStack.back().Inst->getParent() == &Block)
WorkStack.pop_back();
};
traverseBlock(HVC.DT.getRootNode(), traverseBlock);
assert(WorkStack.empty());
// AddrGroups are formed.
// Remove groups of size 1.
erase_if(AddrGroups, [](auto &G) { return G.second.size() == 1; });
// Remove groups that don't use HVX types.
erase_if(AddrGroups, [&](auto &G) {
return !llvm::any_of(
G.second, [&](auto &I) { return HVC.HST.isTypeForHVX(I.ValTy); });
});
return !AddrGroups.empty();
}
auto AlignVectors::createLoadGroups(const AddrList &Group) const -> MoveList {
// Form load groups.
// To avoid complications with moving code across basic blocks, only form
// groups that are contained within a single basic block.
auto getUpwardDeps = [](Instruction *In, Instruction *Base) {
BasicBlock *Parent = Base->getParent();
assert(In->getParent() == Parent &&
"Base and In should be in the same block");
assert(Base->comesBefore(In) && "Base should come before In");
DepList Deps;
std::deque<Instruction *> WorkQ = {In};
while (!WorkQ.empty()) {
Instruction *D = WorkQ.front();
WorkQ.pop_front();
Deps.insert(D);
for (Value *Op : D->operands()) {
if (auto *I = dyn_cast<Instruction>(Op)) {
if (I->getParent() == Parent && Base->comesBefore(I))
WorkQ.push_back(I);
}
}
}
return Deps;
};
auto tryAddTo = [&](const AddrInfo &Info, MoveGroup &Move) {
assert(!Move.Main.empty() && "Move group should have non-empty Main");
// Don't mix HVX and non-HVX instructions.
if (Move.IsHvx != isHvx(Info))
return false;
// Leading instruction in the load group.
Instruction *Base = Move.Main.front();
if (Base->getParent() != Info.Inst->getParent())
return false;
auto isSafeToMoveToBase = [&](const Instruction *I) {
return HVC.isSafeToMoveBeforeInBB(*I, Base->getIterator());
};
DepList Deps = getUpwardDeps(Info.Inst, Base);
if (!llvm::all_of(Deps, isSafeToMoveToBase))
return false;
// The dependencies will be moved together with the load, so make sure
// that none of them could be moved independently in another group.
Deps.erase(Info.Inst);
auto inAddrMap = [&](Instruction *I) { return AddrGroups.count(I) > 0; };
if (llvm::any_of(Deps, inAddrMap))
return false;
Move.Main.push_back(Info.Inst);
llvm::append_range(Move.Deps, Deps);
return true;
};
MoveList LoadGroups;
for (const AddrInfo &Info : Group) {
if (!Info.Inst->mayReadFromMemory())
continue;
if (LoadGroups.empty() || !tryAddTo(Info, LoadGroups.back()))
LoadGroups.emplace_back(Info, Group.front().Inst, isHvx(Info), true);
}
// Erase singleton groups.
erase_if(LoadGroups, [](const MoveGroup &G) { return G.Main.size() <= 1; });
return LoadGroups;
}
auto AlignVectors::createStoreGroups(const AddrList &Group) const -> MoveList {
// Form store groups.
// To avoid complications with moving code across basic blocks, only form
// groups that are contained within a single basic block.
auto tryAddTo = [&](const AddrInfo &Info, MoveGroup &Move) {
assert(!Move.Main.empty() && "Move group should have non-empty Main");
// For stores with return values we'd have to collect downward depenencies.
// There are no such stores that we handle at the moment, so omit that.
assert(Info.Inst->getType()->isVoidTy() &&
"Not handling stores with return values");
// Don't mix HVX and non-HVX instructions.
if (Move.IsHvx != isHvx(Info))
return false;
// For stores we need to be careful whether it's safe to move them.
// Stores that are otherwise safe to move together may not appear safe
// to move over one another (i.e. isSafeToMoveBefore may return false).
Instruction *Base = Move.Main.front();
if (Base->getParent() != Info.Inst->getParent())
return false;
if (!HVC.isSafeToMoveBeforeInBB(*Info.Inst, Base->getIterator(), Move.Main))
return false;
Move.Main.push_back(Info.Inst);
return true;
};
MoveList StoreGroups;
for (auto I = Group.rbegin(), E = Group.rend(); I != E; ++I) {
const AddrInfo &Info = *I;
if (!Info.Inst->mayWriteToMemory())
continue;
if (StoreGroups.empty() || !tryAddTo(Info, StoreGroups.back()))
StoreGroups.emplace_back(Info, Group.front().Inst, isHvx(Info), false);
}
// Erase singleton groups.
erase_if(StoreGroups, [](const MoveGroup &G) { return G.Main.size() <= 1; });
return StoreGroups;
}
auto AlignVectors::move(const MoveGroup &Move) const -> bool {
assert(!Move.Main.empty() && "Move group should have non-empty Main");
Instruction *Where = Move.Main.front();
if (Move.IsLoad) {
// Move all deps to before Where, keeping order.
for (Instruction *D : Move.Deps)
D->moveBefore(Where);
// Move all main instructions to after Where, keeping order.
ArrayRef<Instruction *> Main(Move.Main);
for (Instruction *M : Main.drop_front(1)) {
M->moveAfter(Where);
Where = M;
}
} else {
// NOTE: Deps are empty for "store" groups. If they need to be
// non-empty, decide on the order.
assert(Move.Deps.empty());
// Move all main instructions to before Where, inverting order.
ArrayRef<Instruction *> Main(Move.Main);
for (Instruction *M : Main.drop_front(1)) {
M->moveBefore(Where);
Where = M;
}
}
return Move.Main.size() + Move.Deps.size() > 1;
}
auto AlignVectors::realignGroup(const MoveGroup &Move) const -> bool {
// TODO: Needs support for masked loads/stores of "scalar" vectors.
if (!Move.IsHvx)
return false;
// Return the element with the maximum alignment from Range,
// where GetValue obtains the value to compare from an element.
auto getMaxOf = [](auto Range, auto GetValue) {
return *std::max_element(
Range.begin(), Range.end(),
[&GetValue](auto &A, auto &B) { return GetValue(A) < GetValue(B); });
};
const AddrList &BaseInfos = AddrGroups.at(Move.Base);
// Conceptually, there is a vector of N bytes covering the addresses
// starting from the minimum offset (i.e. Base.Addr+Start). This vector
// represents a contiguous memory region that spans all accessed memory
// locations.
// The correspondence between loaded or stored values will be expressed
// in terms of this vector. For example, the 0th element of the vector
// from the Base address info will start at byte Start from the beginning
// of this conceptual vector.
//
// This vector will be loaded/stored starting at the nearest down-aligned
// address and the amount od the down-alignment will be AlignVal:
// valign(load_vector(align_down(Base+Start)), AlignVal)
std::set<Instruction *> TestSet(Move.Main.begin(), Move.Main.end());
AddrList MoveInfos;
llvm::copy_if(
BaseInfos, std::back_inserter(MoveInfos),
[&TestSet](const AddrInfo &AI) { return TestSet.count(AI.Inst); });
// Maximum alignment present in the whole address group.
const AddrInfo &WithMaxAlign =
getMaxOf(BaseInfos, [](const AddrInfo &AI) { return AI.HaveAlign; });
Align MaxGiven = WithMaxAlign.HaveAlign;
// Minimum alignment present in the move address group.
const AddrInfo &WithMinOffset =
getMaxOf(MoveInfos, [](const AddrInfo &AI) { return -AI.Offset; });
const AddrInfo &WithMaxNeeded =
getMaxOf(MoveInfos, [](const AddrInfo &AI) { return AI.NeedAlign; });
Align MinNeeded = WithMaxNeeded.NeedAlign;
// Set the builder at the top instruction in the move group.
Instruction *TopIn = Move.IsLoad ? Move.Main.front() : Move.Main.back();
IRBuilder<> Builder(TopIn);
Value *AlignAddr = nullptr; // Actual aligned address.
Value *AlignVal = nullptr; // Right-shift amount (for valign).
if (MinNeeded <= MaxGiven) {
int Start = WithMinOffset.Offset;
int OffAtMax = WithMaxAlign.Offset;
// Shift the offset of the maximally aligned instruction (OffAtMax)
// back by just enough multiples of the required alignment to cover the
// distance from Start to OffAtMax.
// Calculate the address adjustment amount based on the address with the
// maximum alignment. This is to allow a simple gep instruction instead
// of potential bitcasts to i8*.
int Adjust = -alignTo(OffAtMax - Start, MinNeeded.value());
AlignAddr = createAdjustedPointer(Builder, WithMaxAlign.Addr,
WithMaxAlign.ValTy, Adjust);
int Diff = Start - (OffAtMax + Adjust);
AlignVal = HVC.getConstInt(Diff);
assert(Diff >= 0);
assert(static_cast<decltype(MinNeeded.value())>(Diff) < MinNeeded.value());
} else {
// WithMinOffset is the lowest address in the group,
// WithMinOffset.Addr = Base+Start.
// Align instructions for both HVX (V6_valign) and scalar (S2_valignrb)
// mask off unnecessary bits, so it's ok to just the original pointer as
// the alignment amount.
// Do an explicit down-alignment of the address to avoid creating an
// aligned instruction with an address that is not really aligned.
AlignAddr = createAlignedPointer(Builder, WithMinOffset.Addr,
WithMinOffset.ValTy, MinNeeded.value());
AlignVal = Builder.CreatePtrToInt(WithMinOffset.Addr, HVC.getIntTy());
}
ByteSpan VSpan;
for (const AddrInfo &AI : MoveInfos) {
VSpan.Blocks.emplace_back(AI.Inst, HVC.getSizeOf(AI.ValTy),
AI.Offset - WithMinOffset.Offset);
}
// The aligned loads/stores will use blocks that are either scalars,
// or HVX vectors. Let "sector" be the unified term for such a block.
// blend(scalar, vector) -> sector...
int ScLen = Move.IsHvx ? HVC.HST.getVectorLength()
: std::max<int>(MinNeeded.value(), 4);
assert(!Move.IsHvx || ScLen == 64 || ScLen == 128);
assert(Move.IsHvx || ScLen == 4 || ScLen == 8);
Type *SecTy = HVC.getByteTy(ScLen);
int NumSectors = (VSpan.extent() + ScLen - 1) / ScLen;
bool DoAlign = !HVC.isZero(AlignVal);
if (Move.IsLoad) {
ByteSpan ASpan;
auto *True = HVC.getFullValue(HVC.getBoolTy(ScLen));
auto *Undef = UndefValue::get(SecTy);
for (int i = 0; i != NumSectors + DoAlign; ++i) {
Value *Ptr = createAdjustedPointer(Builder, AlignAddr, SecTy, i * ScLen);
// FIXME: generate a predicated load?
Value *Load = createAlignedLoad(Builder, SecTy, Ptr, ScLen, True, Undef);
// If vector shifting is potentially needed, accumulate metadata
// from source sections of twice the load width.
int Start = (i - DoAlign) * ScLen;
int Width = (1 + DoAlign) * ScLen;
propagateMetadata(cast<Instruction>(Load),
VSpan.section(Start, Width).values());
ASpan.Blocks.emplace_back(Load, ScLen, i * ScLen);
}
if (DoAlign) {
for (int j = 0; j != NumSectors; ++j) {
ASpan[j].Seg.Val = HVC.vralignb(Builder, ASpan[j].Seg.Val,
ASpan[j + 1].Seg.Val, AlignVal);
}
}
for (ByteSpan::Block &B : VSpan) {
ByteSpan ASection = ASpan.section(B.Pos, B.Seg.Size).shift(-B.Pos);
Value *Accum = UndefValue::get(HVC.getByteTy(B.Seg.Size));
for (ByteSpan::Block &S : ASection) {
Value *Pay = HVC.vbytes(Builder, getPayload(S.Seg.Val));
Accum =
HVC.insertb(Builder, Accum, Pay, S.Seg.Start, S.Seg.Size, S.Pos);
}
// Instead of casting everything to bytes for the vselect, cast to the
// original value type. This will avoid complications with casting masks.
// For example, in cases when the original mask applied to i32, it could
// be converted to a mask applicable to i8 via pred_typecast intrinsic,
// but if the mask is not exactly of HVX length, extra handling would be
// needed to make it work.
Type *ValTy = getPayload(B.Seg.Val)->getType();
Value *Cast = Builder.CreateBitCast(Accum, ValTy);
Value *Sel = Builder.CreateSelect(getMask(B.Seg.Val), Cast,
getPassThrough(B.Seg.Val));
B.Seg.Val->replaceAllUsesWith(Sel);
}
} else {
// Stores.
ByteSpan ASpanV, ASpanM;
// Return a vector value corresponding to the input value Val:
// either <1 x Val> for scalar Val, or Val itself for vector Val.
auto MakeVec = [](IRBuilder<> &Builder, Value *Val) -> Value * {
Type *Ty = Val->getType();
if (Ty->isVectorTy())
return Val;
auto *VecTy = VectorType::get(Ty, 1, /*Scalable*/ false);
return Builder.CreateBitCast(Val, VecTy);
};
// Create an extra "undef" sector at the beginning and at the end.
// They will be used as the left/right filler in the vlalign step.
for (int i = (DoAlign ? -1 : 0); i != NumSectors + DoAlign; ++i) {
// For stores, the size of each section is an aligned vector length.
// Adjust the store offsets relative to the section start offset.
ByteSpan VSection = VSpan.section(i * ScLen, ScLen).shift(-i * ScLen);
Value *AccumV = UndefValue::get(SecTy);
Value *AccumM = HVC.getNullValue(SecTy);
for (ByteSpan::Block &S : VSection) {
Value *Pay = getPayload(S.Seg.Val);
Value *Mask = HVC.rescale(Builder, MakeVec(Builder, getMask(S.Seg.Val)),
Pay->getType(), HVC.getByteTy());
AccumM = HVC.insertb(Builder, AccumM, HVC.vbytes(Builder, Mask),
S.Seg.Start, S.Seg.Size, S.Pos);
AccumV = HVC.insertb(Builder, AccumV, HVC.vbytes(Builder, Pay),
S.Seg.Start, S.Seg.Size, S.Pos);
}
ASpanV.Blocks.emplace_back(AccumV, ScLen, i * ScLen);
ASpanM.Blocks.emplace_back(AccumM, ScLen, i * ScLen);
}
// vlalign
if (DoAlign) {
for (int j = 1; j != NumSectors + 2; ++j) {
ASpanV[j - 1].Seg.Val = HVC.vlalignb(Builder, ASpanV[j - 1].Seg.Val,
ASpanV[j].Seg.Val, AlignVal);
ASpanM[j - 1].Seg.Val = HVC.vlalignb(Builder, ASpanM[j - 1].Seg.Val,
ASpanM[j].Seg.Val, AlignVal);
}
}
for (int i = 0; i != NumSectors + DoAlign; ++i) {
Value *Ptr = createAdjustedPointer(Builder, AlignAddr, SecTy, i * ScLen);
Value *Val = ASpanV[i].Seg.Val;
Value *Mask = ASpanM[i].Seg.Val; // bytes
if (!HVC.isUndef(Val) && !HVC.isZero(Mask)) {
Value *Store = createAlignedStore(Builder, Val, Ptr, ScLen,
HVC.vlsb(Builder, Mask));
// If vector shifting is potentially needed, accumulate metadata
// from source sections of twice the store width.
int Start = (i - DoAlign) * ScLen;
int Width = (1 + DoAlign) * ScLen;
propagateMetadata(cast<Instruction>(Store),
VSpan.section(Start, Width).values());
}
}
}
for (auto *Inst : Move.Main)
Inst->eraseFromParent();
return true;
}
auto AlignVectors::run() -> bool {
if (!createAddressGroups())
return false;
bool Changed = false;
MoveList LoadGroups, StoreGroups;
for (auto &G : AddrGroups) {
llvm::append_range(LoadGroups, createLoadGroups(G.second));
llvm::append_range(StoreGroups, createStoreGroups(G.second));
}
for (auto &M : LoadGroups)
Changed |= move(M);
for (auto &M : StoreGroups)
Changed |= move(M);
for (auto &M : LoadGroups)
Changed |= realignGroup(M);
for (auto &M : StoreGroups)
Changed |= realignGroup(M);
return Changed;
}
// --- End AlignVectors
auto HexagonVectorCombine::run() -> bool {
if (!HST.useHVXOps())
return false;
bool Changed = AlignVectors(*this).run();
return Changed;
}
auto HexagonVectorCombine::getIntTy() const -> IntegerType * {
return Type::getInt32Ty(F.getContext());
}
auto HexagonVectorCombine::getByteTy(int ElemCount) const -> Type * {
assert(ElemCount >= 0);
IntegerType *ByteTy = Type::getInt8Ty(F.getContext());
if (ElemCount == 0)
return ByteTy;
return VectorType::get(ByteTy, ElemCount, /*Scalable*/ false);
}
auto HexagonVectorCombine::getBoolTy(int ElemCount) const -> Type * {
assert(ElemCount >= 0);
IntegerType *BoolTy = Type::getInt1Ty(F.getContext());
if (ElemCount == 0)
return BoolTy;
return VectorType::get(BoolTy, ElemCount, /*Scalable*/ false);
}
auto HexagonVectorCombine::getConstInt(int Val) const -> ConstantInt * {
return ConstantInt::getSigned(getIntTy(), Val);
}
auto HexagonVectorCombine::isZero(const Value *Val) const -> bool {
if (auto *C = dyn_cast<Constant>(Val))
return C->isZeroValue();
return false;
}
auto HexagonVectorCombine::getIntValue(const Value *Val) const
-> Optional<APInt> {
if (auto *CI = dyn_cast<ConstantInt>(Val))
return CI->getValue();
return None;
}
auto HexagonVectorCombine::isUndef(const Value *Val) const -> bool {
return isa<UndefValue>(Val);
}
auto HexagonVectorCombine::getSizeOf(const Value *Val) const -> int {
return getSizeOf(Val->getType());
}
auto HexagonVectorCombine::getSizeOf(const Type *Ty) const -> int {
return DL.getTypeStoreSize(const_cast<Type *>(Ty)).getFixedValue();
}
auto HexagonVectorCombine::getAllocSizeOf(const Type *Ty) const -> int {
return DL.getTypeAllocSize(const_cast<Type *>(Ty)).getFixedValue();
}
auto HexagonVectorCombine::getTypeAlignment(Type *Ty) const -> int {
// The actual type may be shorter than the HVX vector, so determine
// the alignment based on subtarget info.
if (HST.isTypeForHVX(Ty))
return HST.getVectorLength();
return DL.getABITypeAlign(Ty).value();
}
auto HexagonVectorCombine::getNullValue(Type *Ty) const -> Constant * {
assert(Ty->isIntOrIntVectorTy());
auto Zero = ConstantInt::get(Ty->getScalarType(), 0);
if (auto *VecTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VecTy->getElementCount(), Zero);
return Zero;
}