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llvm-project/llvm/lib/Transforms/Vectorize/BBVectorize.cpp

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//===- BBVectorize.cpp - A Basic-Block Vectorizer -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a basic-block vectorization pass. The algorithm was
// inspired by that used by the Vienna MAP Vectorizor by Franchetti and Kral,
// et al. It works by looking for chains of pairable operations and then
// pairing them.
//
//===----------------------------------------------------------------------===//
#define BBV_NAME "bb-vectorize"
#include "llvm/Transforms/Vectorize.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Analysis/ValueTracking.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/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/Local.h"
#include <algorithm>
using namespace llvm;
#define DEBUG_TYPE BBV_NAME
static cl::opt<bool>
IgnoreTargetInfo("bb-vectorize-ignore-target-info", cl::init(false),
cl::Hidden, cl::desc("Ignore target information"));
static cl::opt<unsigned>
ReqChainDepth("bb-vectorize-req-chain-depth", cl::init(6), cl::Hidden,
cl::desc("The required chain depth for vectorization"));
static cl::opt<bool>
UseChainDepthWithTI("bb-vectorize-use-chain-depth", cl::init(false),
cl::Hidden, cl::desc("Use the chain depth requirement with"
" target information"));
static cl::opt<unsigned>
SearchLimit("bb-vectorize-search-limit", cl::init(400), cl::Hidden,
cl::desc("The maximum search distance for instruction pairs"));
static cl::opt<bool>
SplatBreaksChain("bb-vectorize-splat-breaks-chain", cl::init(false), cl::Hidden,
cl::desc("Replicating one element to a pair breaks the chain"));
static cl::opt<unsigned>
VectorBits("bb-vectorize-vector-bits", cl::init(128), cl::Hidden,
cl::desc("The size of the native vector registers"));
static cl::opt<unsigned>
MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden,
cl::desc("The maximum number of pairing iterations"));
static cl::opt<bool>
Pow2LenOnly("bb-vectorize-pow2-len-only", cl::init(false), cl::Hidden,
cl::desc("Don't try to form non-2^n-length vectors"));
static cl::opt<unsigned>
MaxInsts("bb-vectorize-max-instr-per-group", cl::init(500), cl::Hidden,
cl::desc("The maximum number of pairable instructions per group"));
static cl::opt<unsigned>
MaxPairs("bb-vectorize-max-pairs-per-group", cl::init(3000), cl::Hidden,
cl::desc("The maximum number of candidate instruction pairs per group"));
static cl::opt<unsigned>
MaxCandPairsForCycleCheck("bb-vectorize-max-cycle-check-pairs", cl::init(200),
cl::Hidden, cl::desc("The maximum number of candidate pairs with which to use"
" a full cycle check"));
static cl::opt<bool>
NoBools("bb-vectorize-no-bools", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize boolean (i1) values"));
static cl::opt<bool>
NoInts("bb-vectorize-no-ints", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize integer values"));
static cl::opt<bool>
NoFloats("bb-vectorize-no-floats", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize floating-point values"));
// FIXME: This should default to false once pointer vector support works.
static cl::opt<bool>
NoPointers("bb-vectorize-no-pointers", cl::init(/*false*/ true), cl::Hidden,
cl::desc("Don't try to vectorize pointer values"));
static cl::opt<bool>
NoCasts("bb-vectorize-no-casts", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize casting (conversion) operations"));
static cl::opt<bool>
NoMath("bb-vectorize-no-math", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize floating-point math intrinsics"));
static cl::opt<bool>
NoBitManipulation("bb-vectorize-no-bitmanip", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize BitManipulation intrinsics"));
static cl::opt<bool>
NoFMA("bb-vectorize-no-fma", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize the fused-multiply-add intrinsic"));
static cl::opt<bool>
NoSelect("bb-vectorize-no-select", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize select instructions"));
static cl::opt<bool>
NoCmp("bb-vectorize-no-cmp", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize comparison instructions"));
static cl::opt<bool>
NoGEP("bb-vectorize-no-gep", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize getelementptr instructions"));
static cl::opt<bool>
NoMemOps("bb-vectorize-no-mem-ops", cl::init(false), cl::Hidden,
cl::desc("Don't try to vectorize loads and stores"));
static cl::opt<bool>
AlignedOnly("bb-vectorize-aligned-only", cl::init(false), cl::Hidden,
cl::desc("Only generate aligned loads and stores"));
static cl::opt<bool>
NoMemOpBoost("bb-vectorize-no-mem-op-boost",
cl::init(false), cl::Hidden,
cl::desc("Don't boost the chain-depth contribution of loads and stores"));
static cl::opt<bool>
FastDep("bb-vectorize-fast-dep", cl::init(false), cl::Hidden,
cl::desc("Use a fast instruction dependency analysis"));
#ifndef NDEBUG
static cl::opt<bool>
DebugInstructionExamination("bb-vectorize-debug-instruction-examination",
cl::init(false), cl::Hidden,
cl::desc("When debugging is enabled, output information on the"
" instruction-examination process"));
static cl::opt<bool>
DebugCandidateSelection("bb-vectorize-debug-candidate-selection",
cl::init(false), cl::Hidden,
cl::desc("When debugging is enabled, output information on the"
" candidate-selection process"));
static cl::opt<bool>
DebugPairSelection("bb-vectorize-debug-pair-selection",
cl::init(false), cl::Hidden,
cl::desc("When debugging is enabled, output information on the"
" pair-selection process"));
static cl::opt<bool>
DebugCycleCheck("bb-vectorize-debug-cycle-check",
cl::init(false), cl::Hidden,
cl::desc("When debugging is enabled, output information on the"
" cycle-checking process"));
static cl::opt<bool>
PrintAfterEveryPair("bb-vectorize-debug-print-after-every-pair",
cl::init(false), cl::Hidden,
cl::desc("When debugging is enabled, dump the basic block after"
" every pair is fused"));
#endif
STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize");
namespace {
struct BBVectorize : public BasicBlockPass {
static char ID; // Pass identification, replacement for typeid
const VectorizeConfig Config;
BBVectorize(const VectorizeConfig &C = VectorizeConfig())
: BasicBlockPass(ID), Config(C) {
initializeBBVectorizePass(*PassRegistry::getPassRegistry());
}
BBVectorize(Pass *P, Function &F, const VectorizeConfig &C)
: BasicBlockPass(ID), Config(C) {
AA = &P->getAnalysis<AAResultsWrapperPass>().getAAResults();
DT = &P->getAnalysis<DominatorTreeWrapperPass>().getDomTree();
SE = &P->getAnalysis<ScalarEvolutionWrapperPass>().getSE();
TLI = &P->getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
TTI = IgnoreTargetInfo
? nullptr
: &P->getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
}
typedef std::pair<Value *, Value *> ValuePair;
typedef std::pair<ValuePair, int> ValuePairWithCost;
typedef std::pair<ValuePair, size_t> ValuePairWithDepth;
typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair
typedef std::pair<VPPair, unsigned> VPPairWithType;
AliasAnalysis *AA;
DominatorTree *DT;
ScalarEvolution *SE;
const TargetLibraryInfo *TLI;
const TargetTransformInfo *TTI;
// FIXME: const correct?
bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false);
bool getCandidatePairs(BasicBlock &BB,
BasicBlock::iterator &Start,
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &FixedOrderPairs,
DenseMap<ValuePair, int> &CandidatePairCostSavings,
std::vector<Value *> &PairableInsts, bool NonPow2Len);
// FIXME: The current implementation does not account for pairs that
// are connected in multiple ways. For example:
// C1 = A1 / A2; C2 = A2 / A1 (which may be both direct and a swap)
enum PairConnectionType {
PairConnectionDirect,
PairConnectionSwap,
PairConnectionSplat
};
void computeConnectedPairs(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
std::vector<Value *> &PairableInsts,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes);
void buildDepMap(BasicBlock &BB,
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
std::vector<Value *> &PairableInsts,
DenseSet<ValuePair> &PairableInstUsers);
void choosePairs(DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
DenseMap<ValuePair, int> &CandidatePairCostSavings,
std::vector<Value *> &PairableInsts,
DenseSet<ValuePair> &FixedOrderPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<Value *, Value *>& ChosenPairs);
void fuseChosenPairs(BasicBlock &BB,
std::vector<Value *> &PairableInsts,
DenseMap<Value *, Value *>& ChosenPairs,
DenseSet<ValuePair> &FixedOrderPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps);
bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore);
bool areInstsCompatible(Instruction *I, Instruction *J,
bool IsSimpleLoadStore, bool NonPow2Len,
int &CostSavings, int &FixedOrder);
bool trackUsesOfI(DenseSet<Value *> &Users,
AliasSetTracker &WriteSet, Instruction *I,
Instruction *J, bool UpdateUsers = true,
DenseSet<ValuePair> *LoadMoveSetPairs = nullptr);
void computePairsConnectedTo(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
std::vector<Value *> &PairableInsts,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes,
ValuePair P);
bool pairsConflict(ValuePair P, ValuePair Q,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<ValuePair, std::vector<ValuePair> >
*PairableInstUserMap = nullptr,
DenseSet<VPPair> *PairableInstUserPairSet = nullptr);
bool pairWillFormCycle(ValuePair P,
DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUsers,
DenseSet<ValuePair> &CurrentPairs);
void pruneDAGFor(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
std::vector<Value *> &PairableInsts,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
DenseSet<VPPair> &PairableInstUserPairSet,
DenseMap<Value *, Value *> &ChosenPairs,
DenseMap<ValuePair, size_t> &DAG,
DenseSet<ValuePair> &PrunedDAG, ValuePair J,
bool UseCycleCheck);
void buildInitialDAGFor(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
std::vector<Value *> &PairableInsts,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<Value *, Value *> &ChosenPairs,
DenseMap<ValuePair, size_t> &DAG, ValuePair J);
void findBestDAGFor(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
DenseMap<ValuePair, int> &CandidatePairCostSavings,
std::vector<Value *> &PairableInsts,
DenseSet<ValuePair> &FixedOrderPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
DenseSet<VPPair> &PairableInstUserPairSet,
DenseMap<Value *, Value *> &ChosenPairs,
DenseSet<ValuePair> &BestDAG, size_t &BestMaxDepth,
int &BestEffSize, Value *II, std::vector<Value *>&JJ,
bool UseCycleCheck);
Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I,
Instruction *J, unsigned o);
void fillNewShuffleMask(LLVMContext& Context, Instruction *J,
unsigned MaskOffset, unsigned NumInElem,
unsigned NumInElem1, unsigned IdxOffset,
std::vector<Constant*> &Mask);
Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I,
Instruction *J);
bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J,
unsigned o, Value *&LOp, unsigned numElemL,
Type *ArgTypeL, Type *ArgTypeR, bool IBeforeJ,
unsigned IdxOff = 0);
Value *getReplacementInput(LLVMContext& Context, Instruction *I,
Instruction *J, unsigned o, bool IBeforeJ);
void getReplacementInputsForPair(LLVMContext& Context, Instruction *I,
Instruction *J, SmallVectorImpl<Value *> &ReplacedOperands,
bool IBeforeJ);
void replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
Instruction *J, Instruction *K,
Instruction *&InsertionPt, Instruction *&K1,
Instruction *&K2);
void collectPairLoadMoveSet(BasicBlock &BB,
DenseMap<Value *, Value *> &ChosenPairs,
DenseMap<Value *, std::vector<Value *> > &LoadMoveSet,
DenseSet<ValuePair> &LoadMoveSetPairs,
Instruction *I);
void collectLoadMoveSet(BasicBlock &BB,
std::vector<Value *> &PairableInsts,
DenseMap<Value *, Value *> &ChosenPairs,
DenseMap<Value *, std::vector<Value *> > &LoadMoveSet,
DenseSet<ValuePair> &LoadMoveSetPairs);
bool canMoveUsesOfIAfterJ(BasicBlock &BB,
DenseSet<ValuePair> &LoadMoveSetPairs,
Instruction *I, Instruction *J);
void moveUsesOfIAfterJ(BasicBlock &BB,
DenseSet<ValuePair> &LoadMoveSetPairs,
Instruction *&InsertionPt,
Instruction *I, Instruction *J);
bool vectorizeBB(BasicBlock &BB) {
if (skipBasicBlock(BB))
return false;
if (!DT->isReachableFromEntry(&BB)) {
DEBUG(dbgs() << "BBV: skipping unreachable " << BB.getName() <<
" in " << BB.getParent()->getName() << "\n");
return false;
}
DEBUG(if (TTI) dbgs() << "BBV: using target information\n");
bool changed = false;
// Iterate a sufficient number of times to merge types of size 1 bit,
// then 2 bits, then 4, etc. up to half of the target vector width of the
// target vector register.
unsigned n = 1;
for (unsigned v = 2;
(TTI || v <= Config.VectorBits) &&
(!Config.MaxIter || n <= Config.MaxIter);
v *= 2, ++n) {
DEBUG(dbgs() << "BBV: fusing loop #" << n <<
" for " << BB.getName() << " in " <<
BB.getParent()->getName() << "...\n");
if (vectorizePairs(BB))
changed = true;
else
break;
}
if (changed && !Pow2LenOnly) {
++n;
for (; !Config.MaxIter || n <= Config.MaxIter; ++n) {
DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " <<
n << " for " << BB.getName() << " in " <<
BB.getParent()->getName() << "...\n");
if (!vectorizePairs(BB, true)) break;
}
}
DEBUG(dbgs() << "BBV: done!\n");
return changed;
}
bool runOnBasicBlock(BasicBlock &BB) override {
// OptimizeNone check deferred to vectorizeBB().
AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
TTI = IgnoreTargetInfo
? nullptr
: &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(
*BB.getParent());
return vectorizeBB(BB);
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
BasicBlockPass::getAnalysisUsage(AU);
AU.addRequired<AAResultsWrapperPass>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<ScalarEvolutionWrapperPass>();
AU.addRequired<TargetLibraryInfoWrapperPass>();
AU.addRequired<TargetTransformInfoWrapperPass>();
AU.addPreserved<DominatorTreeWrapperPass>();
AU.addPreserved<GlobalsAAWrapperPass>();
AU.addPreserved<ScalarEvolutionWrapperPass>();
AU.addPreserved<SCEVAAWrapperPass>();
AU.setPreservesCFG();
}
static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) {
assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() &&
"Cannot form vector from incompatible scalar types");
Type *STy = ElemTy->getScalarType();
unsigned numElem;
if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) {
numElem = VTy->getNumElements();
} else {
numElem = 1;
}
if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) {
numElem += VTy->getNumElements();
} else {
numElem += 1;
}
return VectorType::get(STy, numElem);
}
static inline void getInstructionTypes(Instruction *I,
Type *&T1, Type *&T2) {
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
// For stores, it is the value type, not the pointer type that matters
// because the value is what will come from a vector register.
Value *IVal = SI->getValueOperand();
T1 = IVal->getType();
} else {
T1 = I->getType();
}
if (CastInst *CI = dyn_cast<CastInst>(I))
T2 = CI->getSrcTy();
else
T2 = T1;
if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
T2 = SI->getCondition()->getType();
} else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) {
T2 = SI->getOperand(0)->getType();
} else if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
T2 = CI->getOperand(0)->getType();
}
}
// Returns the weight associated with the provided value. A chain of
// candidate pairs has a length given by the sum of the weights of its
// members (one weight per pair; the weight of each member of the pair
// is assumed to be the same). This length is then compared to the
// chain-length threshold to determine if a given chain is significant
// enough to be vectorized. The length is also used in comparing
// candidate chains where longer chains are considered to be better.
// Note: when this function returns 0, the resulting instructions are
// not actually fused.
inline size_t getDepthFactor(Value *V) {
// InsertElement and ExtractElement have a depth factor of zero. This is
// for two reasons: First, they cannot be usefully fused. Second, because
// the pass generates a lot of these, they can confuse the simple metric
// used to compare the dags in the next iteration. Thus, giving them a
// weight of zero allows the pass to essentially ignore them in
// subsequent iterations when looking for vectorization opportunities
// while still tracking dependency chains that flow through those
// instructions.
if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V))
return 0;
// Give a load or store half of the required depth so that load/store
// pairs will vectorize.
if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V)))
return Config.ReqChainDepth/2;
return 1;
}
// Returns the cost of the provided instruction using TTI.
// This does not handle loads and stores.
unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2,
TargetTransformInfo::OperandValueKind Op1VK =
TargetTransformInfo::OK_AnyValue,
TargetTransformInfo::OperandValueKind Op2VK =
TargetTransformInfo::OK_AnyValue,
const Instruction *I = nullptr) {
switch (Opcode) {
default: break;
case Instruction::GetElementPtr:
// We mark this instruction as zero-cost because scalar GEPs are usually
// lowered to the instruction addressing mode. At the moment we don't
// generate vector GEPs.
return 0;
case Instruction::Br:
return TTI->getCFInstrCost(Opcode);
case Instruction::PHI:
return 0;
case Instruction::Add:
case Instruction::FAdd:
case Instruction::Sub:
case Instruction::FSub:
case Instruction::Mul:
case Instruction::FMul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::FDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::FRem:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
return TTI->getArithmeticInstrCost(Opcode, T1, Op1VK, Op2VK);
case Instruction::Select:
case Instruction::ICmp:
case Instruction::FCmp:
return TTI->getCmpSelInstrCost(Opcode, T1, T2, I);
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::FPExt:
case Instruction::PtrToInt:
case Instruction::IntToPtr:
case Instruction::SIToFP:
case Instruction::UIToFP:
case Instruction::Trunc:
case Instruction::FPTrunc:
case Instruction::BitCast:
case Instruction::ShuffleVector:
return TTI->getCastInstrCost(Opcode, T1, T2, I);
}
return 1;
}
// This determines the relative offset of two loads or stores, returning
// true if the offset could be determined to be some constant value.
// For example, if OffsetInElmts == 1, then J accesses the memory directly
// after I; if OffsetInElmts == -1 then I accesses the memory
// directly after J.
bool getPairPtrInfo(Instruction *I, Instruction *J,
Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment,
unsigned &IAddressSpace, unsigned &JAddressSpace,
int64_t &OffsetInElmts, bool ComputeOffset = true) {
OffsetInElmts = 0;
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
LoadInst *LJ = cast<LoadInst>(J);
IPtr = LI->getPointerOperand();
JPtr = LJ->getPointerOperand();
IAlignment = LI->getAlignment();
JAlignment = LJ->getAlignment();
IAddressSpace = LI->getPointerAddressSpace();
JAddressSpace = LJ->getPointerAddressSpace();
} else {
StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J);
IPtr = SI->getPointerOperand();
JPtr = SJ->getPointerOperand();
IAlignment = SI->getAlignment();
JAlignment = SJ->getAlignment();
IAddressSpace = SI->getPointerAddressSpace();
JAddressSpace = SJ->getPointerAddressSpace();
}
if (!ComputeOffset)
return true;
const SCEV *IPtrSCEV = SE->getSCEV(IPtr);
const SCEV *JPtrSCEV = SE->getSCEV(JPtr);
// If this is a trivial offset, then we'll get something like
// 1*sizeof(type). With target data, which we need anyway, this will get
// constant folded into a number.
const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV);
if (const SCEVConstant *ConstOffSCEV =
dyn_cast<SCEVConstant>(OffsetSCEV)) {
ConstantInt *IntOff = ConstOffSCEV->getValue();
int64_t Offset = IntOff->getSExtValue();
const DataLayout &DL = I->getModule()->getDataLayout();
Type *VTy = IPtr->getType()->getPointerElementType();
int64_t VTyTSS = (int64_t)DL.getTypeStoreSize(VTy);
Type *VTy2 = JPtr->getType()->getPointerElementType();
if (VTy != VTy2 && Offset < 0) {
int64_t VTy2TSS = (int64_t)DL.getTypeStoreSize(VTy2);
OffsetInElmts = Offset/VTy2TSS;
return (std::abs(Offset) % VTy2TSS) == 0;
}
OffsetInElmts = Offset/VTyTSS;
return (std::abs(Offset) % VTyTSS) == 0;
}
return false;
}
// Returns true if the provided CallInst represents an intrinsic that can
// be vectorized.
bool isVectorizableIntrinsic(CallInst* I) {
Function *F = I->getCalledFunction();
if (!F) return false;
Intrinsic::ID IID = F->getIntrinsicID();
if (!IID) return false;
switch(IID) {
default:
return false;
case Intrinsic::sqrt:
case Intrinsic::powi:
case Intrinsic::sin:
case Intrinsic::cos:
case Intrinsic::log:
case Intrinsic::log2:
case Intrinsic::log10:
case Intrinsic::exp:
case Intrinsic::exp2:
case Intrinsic::pow:
case Intrinsic::round:
case Intrinsic::copysign:
case Intrinsic::ceil:
case Intrinsic::nearbyint:
case Intrinsic::rint:
case Intrinsic::trunc:
case Intrinsic::floor:
case Intrinsic::fabs:
case Intrinsic::minnum:
case Intrinsic::maxnum:
return Config.VectorizeMath;
case Intrinsic::bswap:
case Intrinsic::ctpop:
case Intrinsic::ctlz:
case Intrinsic::cttz:
return Config.VectorizeBitManipulations;
case Intrinsic::fma:
case Intrinsic::fmuladd:
return Config.VectorizeFMA;
}
}
bool isPureIEChain(InsertElementInst *IE) {
InsertElementInst *IENext = IE;
do {
if (!isa<UndefValue>(IENext->getOperand(0)) &&
!isa<InsertElementInst>(IENext->getOperand(0))) {
return false;
}
} while ((IENext =
dyn_cast<InsertElementInst>(IENext->getOperand(0))));
return true;
}
};
// This function implements one vectorization iteration on the provided
// basic block. It returns true if the block is changed.
bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) {
bool ShouldContinue;
BasicBlock::iterator Start = BB.getFirstInsertionPt();
std::vector<Value *> AllPairableInsts;
DenseMap<Value *, Value *> AllChosenPairs;
DenseSet<ValuePair> AllFixedOrderPairs;
DenseMap<VPPair, unsigned> AllPairConnectionTypes;
DenseMap<ValuePair, std::vector<ValuePair> > AllConnectedPairs,
AllConnectedPairDeps;
do {
std::vector<Value *> PairableInsts;
DenseMap<Value *, std::vector<Value *> > CandidatePairs;
DenseSet<ValuePair> FixedOrderPairs;
DenseMap<ValuePair, int> CandidatePairCostSavings;
ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs,
FixedOrderPairs,
CandidatePairCostSavings,
PairableInsts, NonPow2Len);
if (PairableInsts.empty()) continue;
// Build the candidate pair set for faster lookups.
DenseSet<ValuePair> CandidatePairsSet;
for (DenseMap<Value *, std::vector<Value *> >::iterator I =
CandidatePairs.begin(), E = CandidatePairs.end(); I != E; ++I)
for (std::vector<Value *>::iterator J = I->second.begin(),
JE = I->second.end(); J != JE; ++J)
CandidatePairsSet.insert(ValuePair(I->first, *J));
// Now we have a map of all of the pairable instructions and we need to
// select the best possible pairing. A good pairing is one such that the
// users of the pair are also paired. This defines a (directed) forest
// over the pairs such that two pairs are connected iff the second pair
// uses the first.
// Note that it only matters that both members of the second pair use some
// element of the first pair (to allow for splatting).
DenseMap<ValuePair, std::vector<ValuePair> > ConnectedPairs,
ConnectedPairDeps;
DenseMap<VPPair, unsigned> PairConnectionTypes;
computeConnectedPairs(CandidatePairs, CandidatePairsSet,
PairableInsts, ConnectedPairs, PairConnectionTypes);
if (ConnectedPairs.empty()) continue;
for (DenseMap<ValuePair, std::vector<ValuePair> >::iterator
I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
I != IE; ++I)
for (std::vector<ValuePair>::iterator J = I->second.begin(),
JE = I->second.end(); J != JE; ++J)
ConnectedPairDeps[*J].push_back(I->first);
// Build the pairable-instruction dependency map
DenseSet<ValuePair> PairableInstUsers;
buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers);
// There is now a graph of the connected pairs. For each variable, pick
// the pairing with the largest dag meeting the depth requirement on at
// least one branch. Then select all pairings that are part of that dag
// and remove them from the list of available pairings and pairable
// variables.
DenseMap<Value *, Value *> ChosenPairs;
choosePairs(CandidatePairs, CandidatePairsSet,
CandidatePairCostSavings,
PairableInsts, FixedOrderPairs, PairConnectionTypes,
ConnectedPairs, ConnectedPairDeps,
PairableInstUsers, ChosenPairs);
if (ChosenPairs.empty()) continue;
AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(),
PairableInsts.end());
AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end());
// Only for the chosen pairs, propagate information on fixed-order pairs,
// pair connections, and their types to the data structures used by the
// pair fusion procedures.
for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(),
IE = ChosenPairs.end(); I != IE; ++I) {
if (FixedOrderPairs.count(*I))
AllFixedOrderPairs.insert(*I);
else if (FixedOrderPairs.count(ValuePair(I->second, I->first)))
AllFixedOrderPairs.insert(ValuePair(I->second, I->first));
for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin();
J != IE; ++J) {
DenseMap<VPPair, unsigned>::iterator K =
PairConnectionTypes.find(VPPair(*I, *J));
if (K != PairConnectionTypes.end()) {
AllPairConnectionTypes.insert(*K);
} else {
K = PairConnectionTypes.find(VPPair(*J, *I));
if (K != PairConnectionTypes.end())
AllPairConnectionTypes.insert(*K);
}
}
}
for (DenseMap<ValuePair, std::vector<ValuePair> >::iterator
I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
I != IE; ++I)
for (std::vector<ValuePair>::iterator J = I->second.begin(),
JE = I->second.end(); J != JE; ++J)
if (AllPairConnectionTypes.count(VPPair(I->first, *J))) {
AllConnectedPairs[I->first].push_back(*J);
AllConnectedPairDeps[*J].push_back(I->first);
}
} while (ShouldContinue);
if (AllChosenPairs.empty()) return false;
NumFusedOps += AllChosenPairs.size();
// A set of pairs has now been selected. It is now necessary to replace the
// paired instructions with vector instructions. For this procedure each
// operand must be replaced with a vector operand. This vector is formed
// by using build_vector on the old operands. The replaced values are then
// replaced with a vector_extract on the result. Subsequent optimization
// passes should coalesce the build/extract combinations.
fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs,
AllPairConnectionTypes,
AllConnectedPairs, AllConnectedPairDeps);
// It is important to cleanup here so that future iterations of this
// function have less work to do.
(void)SimplifyInstructionsInBlock(&BB, TLI);
return true;
}
// This function returns true if the provided instruction is capable of being
// fused into a vector instruction. This determination is based only on the
// type and other attributes of the instruction.
bool BBVectorize::isInstVectorizable(Instruction *I,
bool &IsSimpleLoadStore) {
IsSimpleLoadStore = false;
if (CallInst *C = dyn_cast<CallInst>(I)) {
if (!isVectorizableIntrinsic(C))
return false;
} else if (LoadInst *L = dyn_cast<LoadInst>(I)) {
// Vectorize simple loads if possbile:
IsSimpleLoadStore = L->isSimple();
if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
return false;
} else if (StoreInst *S = dyn_cast<StoreInst>(I)) {
// Vectorize simple stores if possbile:
IsSimpleLoadStore = S->isSimple();
if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
return false;
} else if (CastInst *C = dyn_cast<CastInst>(I)) {
// We can vectorize casts, but not casts of pointer types, etc.
if (!Config.VectorizeCasts)
return false;
Type *SrcTy = C->getSrcTy();
if (!SrcTy->isSingleValueType())
return false;
Type *DestTy = C->getDestTy();
if (!DestTy->isSingleValueType())
return false;
} else if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
if (!Config.VectorizeSelect)
return false;
// We can vectorize a select if either all operands are scalars,
// or all operands are vectors. Trying to "widen" a select between
// vectors that has a scalar condition results in a malformed select.
// FIXME: We could probably be smarter about this by rewriting the select
// with different types instead.
return (SI->getCondition()->getType()->isVectorTy() ==
SI->getTrueValue()->getType()->isVectorTy());
} else if (isa<CmpInst>(I)) {
if (!Config.VectorizeCmp)
return false;
} else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) {
if (!Config.VectorizeGEP)
return false;
// Currently, vector GEPs exist only with one index.
if (G->getNumIndices() != 1)
return false;
} else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) ||
isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) {
return false;
}
Type *T1, *T2;
getInstructionTypes(I, T1, T2);
// Not every type can be vectorized...
if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) ||
!(VectorType::isValidElementType(T2) || T2->isVectorTy()))
return false;
if (T1->getScalarSizeInBits() == 1) {
if (!Config.VectorizeBools)
return false;
} else {
if (!Config.VectorizeInts && T1->isIntOrIntVectorTy())
return false;
}
if (T2->getScalarSizeInBits() == 1) {
if (!Config.VectorizeBools)
return false;
} else {
if (!Config.VectorizeInts && T2->isIntOrIntVectorTy())
return false;
}
if (!Config.VectorizeFloats
&& (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy()))
return false;
// Don't vectorize target-specific types.
if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy())
return false;
if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy())
return false;
if (!Config.VectorizePointers && (T1->getScalarType()->isPointerTy() ||
T2->getScalarType()->isPointerTy()))
return false;
if (!TTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits ||
T2->getPrimitiveSizeInBits() >= Config.VectorBits))
return false;
return true;
}
// This function returns true if the two provided instructions are compatible
// (meaning that they can be fused into a vector instruction). This assumes
// that I has already been determined to be vectorizable and that J is not
// in the use dag of I.
bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J,
bool IsSimpleLoadStore, bool NonPow2Len,
int &CostSavings, int &FixedOrder) {
DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I <<
" <-> " << *J << "\n");
CostSavings = 0;
FixedOrder = 0;
// Loads and stores can be merged if they have different alignments,
// but are otherwise the same.
if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment |
(NonPow2Len ? Instruction::CompareUsingScalarTypes : 0)))
return false;
Type *IT1, *IT2, *JT1, *JT2;
getInstructionTypes(I, IT1, IT2);
getInstructionTypes(J, JT1, JT2);
unsigned MaxTypeBits = std::max(
IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(),
IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits());
if (!TTI && MaxTypeBits > Config.VectorBits)
return false;
// FIXME: handle addsub-type operations!
if (IsSimpleLoadStore) {
Value *IPtr, *JPtr;
unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
int64_t OffsetInElmts = 0;
if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
IAddressSpace, JAddressSpace, OffsetInElmts) &&
std::abs(OffsetInElmts) == 1) {
FixedOrder = (int) OffsetInElmts;
unsigned BottomAlignment = IAlignment;
if (OffsetInElmts < 0) BottomAlignment = JAlignment;
Type *aTypeI = isa<StoreInst>(I) ?
cast<StoreInst>(I)->getValueOperand()->getType() : I->getType();
Type *aTypeJ = isa<StoreInst>(J) ?
cast<StoreInst>(J)->getValueOperand()->getType() : J->getType();
Type *VType = getVecTypeForPair(aTypeI, aTypeJ);
if (Config.AlignedOnly) {
// An aligned load or store is possible only if the instruction
// with the lower offset has an alignment suitable for the
// vector type.
const DataLayout &DL = I->getModule()->getDataLayout();
unsigned VecAlignment = DL.getPrefTypeAlignment(VType);
if (BottomAlignment < VecAlignment)
return false;
}
if (TTI) {
unsigned ICost = TTI->getMemoryOpCost(I->getOpcode(), aTypeI,
IAlignment, IAddressSpace);
unsigned JCost = TTI->getMemoryOpCost(J->getOpcode(), aTypeJ,
JAlignment, JAddressSpace);
unsigned VCost = TTI->getMemoryOpCost(I->getOpcode(), VType,
BottomAlignment,
IAddressSpace);
ICost += TTI->getAddressComputationCost(aTypeI);
JCost += TTI->getAddressComputationCost(aTypeJ);
VCost += TTI->getAddressComputationCost(VType);
if (VCost > ICost + JCost)
return false;
// We don't want to fuse to a type that will be split, even
// if the two input types will also be split and there is no other
// associated cost.
unsigned VParts = TTI->getNumberOfParts(VType);
if (VParts > 1)
return false;
else if (!VParts && VCost == ICost + JCost)
return false;
CostSavings = ICost + JCost - VCost;
}
} else {
return false;
}
} else if (TTI) {
TargetTransformInfo::OperandValueKind Op1VK =
TargetTransformInfo::OK_AnyValue;
TargetTransformInfo::OperandValueKind Op2VK =
TargetTransformInfo::OK_AnyValue;
unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2, Op1VK, Op2VK, I);
unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2, Op1VK, Op2VK, J);
Type *VT1 = getVecTypeForPair(IT1, JT1),
*VT2 = getVecTypeForPair(IT2, JT2);
// On some targets (example X86) the cost of a vector shift may vary
// depending on whether the second operand is a Uniform or
// NonUniform Constant.
switch (I->getOpcode()) {
default : break;
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
// If both I and J are scalar shifts by constant, then the
// merged vector shift count would be either a constant splat value
// or a non-uniform vector of constants.
if (ConstantInt *CII = dyn_cast<ConstantInt>(I->getOperand(1))) {
if (ConstantInt *CIJ = dyn_cast<ConstantInt>(J->getOperand(1)))
Op2VK = CII == CIJ ? TargetTransformInfo::OK_UniformConstantValue :
TargetTransformInfo::OK_NonUniformConstantValue;
} else {
// Check for a splat of a constant or for a non uniform vector
// of constants.
Value *IOp = I->getOperand(1);
Value *JOp = J->getOperand(1);
if ((isa<ConstantVector>(IOp) || isa<ConstantDataVector>(IOp)) &&
(isa<ConstantVector>(JOp) || isa<ConstantDataVector>(JOp))) {
Op2VK = TargetTransformInfo::OK_NonUniformConstantValue;
Constant *SplatValue = cast<Constant>(IOp)->getSplatValue();
if (SplatValue != nullptr &&
SplatValue == cast<Constant>(JOp)->getSplatValue())
Op2VK = TargetTransformInfo::OK_UniformConstantValue;
}
}
}
// Note that this procedure is incorrect for insert and extract element
// instructions (because combining these often results in a shuffle),
// but this cost is ignored (because insert and extract element
// instructions are assigned a zero depth factor and are not really
// fused in general).
unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2, Op1VK, Op2VK, I);
if (VCost > ICost + JCost)
return false;
// We don't want to fuse to a type that will be split, even
// if the two input types will also be split and there is no other
// associated cost.
unsigned VParts1 = TTI->getNumberOfParts(VT1),
VParts2 = TTI->getNumberOfParts(VT2);
if (VParts1 > 1 || VParts2 > 1)
return false;
else if ((!VParts1 || !VParts2) && VCost == ICost + JCost)
return false;
CostSavings = ICost + JCost - VCost;
}
// The powi,ctlz,cttz intrinsics are special because only the first
// argument is vectorized, the second arguments must be equal.
CallInst *CI = dyn_cast<CallInst>(I);
Function *FI;
if (CI && (FI = CI->getCalledFunction())) {
Intrinsic::ID IID = FI->getIntrinsicID();
if (IID == Intrinsic::powi || IID == Intrinsic::ctlz ||
IID == Intrinsic::cttz) {
Value *A1I = CI->getArgOperand(1),
*A1J = cast<CallInst>(J)->getArgOperand(1);
const SCEV *A1ISCEV = SE->getSCEV(A1I),
*A1JSCEV = SE->getSCEV(A1J);
return (A1ISCEV == A1JSCEV);
}
if (IID && TTI) {
FastMathFlags FMFCI;
if (auto *FPMOCI = dyn_cast<FPMathOperator>(CI))
FMFCI = FPMOCI->getFastMathFlags();
SmallVector<Value *, 4> IArgs(CI->arg_operands());
unsigned ICost = TTI->getIntrinsicInstrCost(IID, IT1, IArgs, FMFCI);
CallInst *CJ = cast<CallInst>(J);
FastMathFlags FMFCJ;
if (auto *FPMOCJ = dyn_cast<FPMathOperator>(CJ))
FMFCJ = FPMOCJ->getFastMathFlags();
SmallVector<Value *, 4> JArgs(CJ->arg_operands());
unsigned JCost = TTI->getIntrinsicInstrCost(IID, JT1, JArgs, FMFCJ);
assert(CI->getNumArgOperands() == CJ->getNumArgOperands() &&
"Intrinsic argument counts differ");
SmallVector<Type*, 4> Tys;
SmallVector<Value *, 4> VecArgs;
for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
if ((IID == Intrinsic::powi || IID == Intrinsic::ctlz ||
IID == Intrinsic::cttz) && i == 1) {
Tys.push_back(CI->getArgOperand(i)->getType());
VecArgs.push_back(CI->getArgOperand(i));
}
else {
Tys.push_back(getVecTypeForPair(CI->getArgOperand(i)->getType(),
CJ->getArgOperand(i)->getType()));
// Add both operands, and then count their scalarization overhead
// with VF 1.
VecArgs.push_back(CI->getArgOperand(i));
VecArgs.push_back(CJ->getArgOperand(i));
}
}
// Compute the scalarization cost here with the original operands (to
// check for uniqueness etc), and then call getIntrinsicInstrCost()
// with the constructed vector types.
Type *RetTy = getVecTypeForPair(IT1, JT1);
unsigned ScalarizationCost = 0;
if (!RetTy->isVoidTy())
ScalarizationCost += TTI->getScalarizationOverhead(RetTy, true, false);
ScalarizationCost += TTI->getOperandsScalarizationOverhead(VecArgs, 1);
FastMathFlags FMFV = FMFCI;
FMFV &= FMFCJ;
unsigned VCost = TTI->getIntrinsicInstrCost(IID, RetTy, Tys, FMFV,
ScalarizationCost);
if (VCost > ICost + JCost)
return false;
// We don't want to fuse to a type that will be split, even
// if the two input types will also be split and there is no other
// associated cost.
unsigned RetParts = TTI->getNumberOfParts(RetTy);
if (RetParts > 1)
return false;
else if (!RetParts && VCost == ICost + JCost)
return false;
for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
if (!Tys[i]->isVectorTy())
continue;
unsigned NumParts = TTI->getNumberOfParts(Tys[i]);
if (NumParts > 1)
return false;
else if (!NumParts && VCost == ICost + JCost)
return false;
}
CostSavings = ICost + JCost - VCost;
}
}
return true;
}
// Figure out whether or not J uses I and update the users and write-set
// structures associated with I. Specifically, Users represents the set of
// instructions that depend on I. WriteSet represents the set
// of memory locations that are dependent on I. If UpdateUsers is true,
// and J uses I, then Users is updated to contain J and WriteSet is updated
// to contain any memory locations to which J writes. The function returns
// true if J uses I. By default, alias analysis is used to determine
// whether J reads from memory that overlaps with a location in WriteSet.
// If LoadMoveSet is not null, then it is a previously-computed map
// where the key is the memory-based user instruction and the value is
// the instruction to be compared with I. So, if LoadMoveSet is provided,
// then the alias analysis is not used. This is necessary because this
// function is called during the process of moving instructions during
// vectorization and the results of the alias analysis are not stable during
// that process.
bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users,
AliasSetTracker &WriteSet, Instruction *I,
Instruction *J, bool UpdateUsers,
DenseSet<ValuePair> *LoadMoveSetPairs) {
bool UsesI = false;
// This instruction may already be marked as a user due, for example, to
// being a member of a selected pair.
if (Users.count(J))
UsesI = true;
if (!UsesI)
for (User::op_iterator JU = J->op_begin(), JE = J->op_end();
JU != JE; ++JU) {
Value *V = *JU;
if (I == V || Users.count(V)) {
UsesI = true;
break;
}
}
if (!UsesI && J->mayReadFromMemory()) {
if (LoadMoveSetPairs) {
UsesI = LoadMoveSetPairs->count(ValuePair(J, I));
} else {
for (AliasSetTracker::iterator W = WriteSet.begin(),
WE = WriteSet.end(); W != WE; ++W) {
if (W->aliasesUnknownInst(J, *AA)) {
UsesI = true;
break;
}
}
}
}
if (UsesI && UpdateUsers) {
if (J->mayWriteToMemory()) WriteSet.add(J);
Users.insert(J);
}
return UsesI;
}
// This function iterates over all instruction pairs in the provided
// basic block and collects all candidate pairs for vectorization.
bool BBVectorize::getCandidatePairs(BasicBlock &BB,
BasicBlock::iterator &Start,
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &FixedOrderPairs,
DenseMap<ValuePair, int> &CandidatePairCostSavings,
std::vector<Value *> &PairableInsts, bool NonPow2Len) {
size_t TotalPairs = 0;
BasicBlock::iterator E = BB.end();
if (Start == E) return false;
bool ShouldContinue = false, IAfterStart = false;
for (BasicBlock::iterator I = Start++; I != E; ++I) {
if (I == Start) IAfterStart = true;
bool IsSimpleLoadStore;
if (!isInstVectorizable(&*I, IsSimpleLoadStore))
continue;
// Look for an instruction with which to pair instruction *I...
DenseSet<Value *> Users;
AliasSetTracker WriteSet(*AA);
if (I->mayWriteToMemory())
WriteSet.add(&*I);
bool JAfterStart = IAfterStart;
BasicBlock::iterator J = std::next(I);
for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) {
if (J == Start)
JAfterStart = true;
// Determine if J uses I, if so, exit the loop.
bool UsesI = trackUsesOfI(Users, WriteSet, &*I, &*J, !Config.FastDep);
if (Config.FastDep) {
// Note: For this heuristic to be effective, independent operations
// must tend to be intermixed. This is likely to be true from some
// kinds of grouped loop unrolling (but not the generic LLVM pass),
// but otherwise may require some kind of reordering pass.
// When using fast dependency analysis,
// stop searching after first use:
if (UsesI) break;
} else {
if (UsesI) continue;
}
// J does not use I, and comes before the first use of I, so it can be
// merged with I if the instructions are compatible.
int CostSavings, FixedOrder;
if (!areInstsCompatible(&*I, &*J, IsSimpleLoadStore, NonPow2Len,
CostSavings, FixedOrder))
continue;
// J is a candidate for merging with I.
if (PairableInsts.empty() ||
PairableInsts[PairableInsts.size() - 1] != &*I) {
PairableInsts.push_back(&*I);
}
CandidatePairs[&*I].push_back(&*J);
++TotalPairs;
if (TTI)
CandidatePairCostSavings.insert(
ValuePairWithCost(ValuePair(&*I, &*J), CostSavings));
if (FixedOrder == 1)
FixedOrderPairs.insert(ValuePair(&*I, &*J));
else if (FixedOrder == -1)
FixedOrderPairs.insert(ValuePair(&*J, &*I));
// The next call to this function must start after the last instruction
// selected during this invocation.
if (JAfterStart) {
Start = std::next(J);
IAfterStart = JAfterStart = false;
}
DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair "
<< *I << " <-> " << *J << " (cost savings: " <<
CostSavings << ")\n");
// If we have already found too many pairs, break here and this function
// will be called again starting after the last instruction selected
// during this invocation.
if (PairableInsts.size() >= Config.MaxInsts ||
TotalPairs >= Config.MaxPairs) {
ShouldContinue = true;
break;
}
}
if (ShouldContinue)
break;
}
DEBUG(dbgs() << "BBV: found " << PairableInsts.size()
<< " instructions with candidate pairs\n");
return ShouldContinue;
}
// Finds candidate pairs connected to the pair P = <PI, PJ>. This means that
// it looks for pairs such that both members have an input which is an
// output of PI or PJ.
void BBVectorize::computePairsConnectedTo(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
std::vector<Value *> &PairableInsts,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes,
ValuePair P) {
StoreInst *SI, *SJ;
// For each possible pairing for this variable, look at the uses of
// the first value...
for (Value::user_iterator I = P.first->user_begin(),
E = P.first->user_end();
I != E; ++I) {
User *UI = *I;
if (isa<LoadInst>(UI)) {
// A pair cannot be connected to a load because the load only takes one
// operand (the address) and it is a scalar even after vectorization.
continue;
} else if ((SI = dyn_cast<StoreInst>(UI)) &&
P.first == SI->getPointerOperand()) {
// Similarly, a pair cannot be connected to a store through its
// pointer operand.
continue;
}
// For each use of the first variable, look for uses of the second
// variable...
for (User *UJ : P.second->users()) {
if ((SJ = dyn_cast<StoreInst>(UJ)) &&
P.second == SJ->getPointerOperand())
continue;
// Look for <I, J>:
if (CandidatePairsSet.count(ValuePair(UI, UJ))) {
VPPair VP(P, ValuePair(UI, UJ));
ConnectedPairs[VP.first].push_back(VP.second);
PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect));
}
// Look for <J, I>:
if (CandidatePairsSet.count(ValuePair(UJ, UI))) {
VPPair VP(P, ValuePair(UJ, UI));
ConnectedPairs[VP.first].push_back(VP.second);
PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap));
}
}
if (Config.SplatBreaksChain) continue;
// Look for cases where just the first value in the pair is used by
// both members of another pair (splatting).
for (Value::user_iterator J = P.first->user_begin(); J != E; ++J) {
User *UJ = *J;
if ((SJ = dyn_cast<StoreInst>(UJ)) &&
P.first == SJ->getPointerOperand())
continue;
if (CandidatePairsSet.count(ValuePair(UI, UJ))) {
VPPair VP(P, ValuePair(UI, UJ));
ConnectedPairs[VP.first].push_back(VP.second);
PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
}
}
}
if (Config.SplatBreaksChain) return;
// Look for cases where just the second value in the pair is used by
// both members of another pair (splatting).
for (Value::user_iterator I = P.second->user_begin(),
E = P.second->user_end();
I != E; ++I) {
User *UI = *I;
if (isa<LoadInst>(UI))
continue;
else if ((SI = dyn_cast<StoreInst>(UI)) &&
P.second == SI->getPointerOperand())
continue;
for (Value::user_iterator J = P.second->user_begin(); J != E; ++J) {
User *UJ = *J;
if ((SJ = dyn_cast<StoreInst>(UJ)) &&
P.second == SJ->getPointerOperand())
continue;
if (CandidatePairsSet.count(ValuePair(UI, UJ))) {
VPPair VP(P, ValuePair(UI, UJ));
ConnectedPairs[VP.first].push_back(VP.second);
PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
}
}
}
}
// This function figures out which pairs are connected. Two pairs are
// connected if some output of the first pair forms an input to both members
// of the second pair.
void BBVectorize::computeConnectedPairs(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
std::vector<Value *> &PairableInsts,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes) {
for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
PE = PairableInsts.end(); PI != PE; ++PI) {
DenseMap<Value *, std::vector<Value *> >::iterator PP =
CandidatePairs.find(*PI);
if (PP == CandidatePairs.end())
continue;
for (std::vector<Value *>::iterator P = PP->second.begin(),
E = PP->second.end(); P != E; ++P)
computePairsConnectedTo(CandidatePairs, CandidatePairsSet,
PairableInsts, ConnectedPairs,
PairConnectionTypes, ValuePair(*PI, *P));
}
DEBUG(size_t TotalPairs = 0;
for (DenseMap<ValuePair, std::vector<ValuePair> >::iterator I =
ConnectedPairs.begin(), IE = ConnectedPairs.end(); I != IE; ++I)
TotalPairs += I->second.size();
dbgs() << "BBV: found " << TotalPairs
<< " pair connections.\n");
}
// This function builds a set of use tuples such that <A, B> is in the set
// if B is in the use dag of A. If B is in the use dag of A, then B
// depends on the output of A.
void BBVectorize::buildDepMap(
BasicBlock &BB,
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
std::vector<Value *> &PairableInsts,
DenseSet<ValuePair> &PairableInstUsers) {
DenseSet<Value *> IsInPair;
for (DenseMap<Value *, std::vector<Value *> >::iterator C =
CandidatePairs.begin(), E = CandidatePairs.end(); C != E; ++C) {
IsInPair.insert(C->first);
IsInPair.insert(C->second.begin(), C->second.end());
}
// Iterate through the basic block, recording all users of each
// pairable instruction.
BasicBlock::iterator E = BB.end(), EL =
BasicBlock::iterator(cast<Instruction>(PairableInsts.back()));
for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) {
if (IsInPair.find(&*I) == IsInPair.end())
continue;
DenseSet<Value *> Users;
AliasSetTracker WriteSet(*AA);
if (I->mayWriteToMemory())
WriteSet.add(&*I);
for (BasicBlock::iterator J = std::next(I); J != E; ++J) {
(void)trackUsesOfI(Users, WriteSet, &*I, &*J);
if (J == EL)
break;
}
for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end();
U != E; ++U) {
if (IsInPair.find(*U) == IsInPair.end()) continue;
PairableInstUsers.insert(ValuePair(&*I, *U));
}
if (I == EL)
break;
}
}
// Returns true if an input to pair P is an output of pair Q and also an
// input of pair Q is an output of pair P. If this is the case, then these
// two pairs cannot be simultaneously fused.
bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<ValuePair, std::vector<ValuePair> > *PairableInstUserMap,
DenseSet<VPPair> *PairableInstUserPairSet) {
// Two pairs are in conflict if they are mutual Users of eachother.
bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) ||
PairableInstUsers.count(ValuePair(P.first, Q.second)) ||
PairableInstUsers.count(ValuePair(P.second, Q.first)) ||
PairableInstUsers.count(ValuePair(P.second, Q.second));
bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) ||
PairableInstUsers.count(ValuePair(Q.first, P.second)) ||
PairableInstUsers.count(ValuePair(Q.second, P.first)) ||
PairableInstUsers.count(ValuePair(Q.second, P.second));
if (PairableInstUserMap) {
// FIXME: The expensive part of the cycle check is not so much the cycle
// check itself but this edge insertion procedure. This needs some
// profiling and probably a different data structure.
if (PUsesQ) {
if (PairableInstUserPairSet->insert(VPPair(Q, P)).second)
(*PairableInstUserMap)[Q].push_back(P);
}
if (QUsesP) {
if (PairableInstUserPairSet->insert(VPPair(P, Q)).second)
(*PairableInstUserMap)[P].push_back(Q);
}
}
return (QUsesP && PUsesQ);
}
// This function walks the use graph of current pairs to see if, starting
// from P, the walk returns to P.
bool BBVectorize::pairWillFormCycle(ValuePair P,
DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
DenseSet<ValuePair> &CurrentPairs) {
DEBUG(if (DebugCycleCheck)
dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> "
<< *P.second << "\n");
// A lookup table of visisted pairs is kept because the PairableInstUserMap
// contains non-direct associations.
DenseSet<ValuePair> Visited;
SmallVector<ValuePair, 32> Q;
// General depth-first post-order traversal:
Q.push_back(P);
do {
ValuePair QTop = Q.pop_back_val();
Visited.insert(QTop);
DEBUG(if (DebugCycleCheck)
dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> "
<< *QTop.second << "\n");
DenseMap<ValuePair, std::vector<ValuePair> >::iterator QQ =
PairableInstUserMap.find(QTop);
if (QQ == PairableInstUserMap.end())
continue;
for (std::vector<ValuePair>::iterator C = QQ->second.begin(),
CE = QQ->second.end(); C != CE; ++C) {
if (*C == P) {
DEBUG(dbgs()
<< "BBV: rejected to prevent non-trivial cycle formation: "
<< QTop.first << " <-> " << C->second << "\n");
return true;
}
if (CurrentPairs.count(*C) && !Visited.count(*C))
Q.push_back(*C);
}
} while (!Q.empty());
return false;
}
// This function builds the initial dag of connected pairs with the
// pair J at the root.
void BBVectorize::buildInitialDAGFor(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
std::vector<Value *> &PairableInsts,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<Value *, Value *> &ChosenPairs,
DenseMap<ValuePair, size_t> &DAG, ValuePair J) {
// Each of these pairs is viewed as the root node of a DAG. The DAG
// is then walked (depth-first). As this happens, we keep track of
// the pairs that compose the DAG and the maximum depth of the DAG.
SmallVector<ValuePairWithDepth, 32> Q;
// General depth-first post-order traversal:
Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
do {
ValuePairWithDepth QTop = Q.back();
// Push each child onto the queue:
bool MoreChildren = false;
size_t MaxChildDepth = QTop.second;
DenseMap<ValuePair, std::vector<ValuePair> >::iterator QQ =
ConnectedPairs.find(QTop.first);
if (QQ != ConnectedPairs.end())
for (std::vector<ValuePair>::iterator k = QQ->second.begin(),
ke = QQ->second.end(); k != ke; ++k) {
// Make sure that this child pair is still a candidate:
if (CandidatePairsSet.count(*k)) {
DenseMap<ValuePair, size_t>::iterator C = DAG.find(*k);
if (C == DAG.end()) {
size_t d = getDepthFactor(k->first);
Q.push_back(ValuePairWithDepth(*k, QTop.second+d));
MoreChildren = true;
} else {
MaxChildDepth = std::max(MaxChildDepth, C->second);
}
}
}
if (!MoreChildren) {
// Record the current pair as part of the DAG:
DAG.insert(ValuePairWithDepth(QTop.first, MaxChildDepth));
Q.pop_back();
}
} while (!Q.empty());
}
// Given some initial dag, prune it by removing conflicting pairs (pairs
// that cannot be simultaneously chosen for vectorization).
void BBVectorize::pruneDAGFor(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
std::vector<Value *> &PairableInsts,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
DenseSet<VPPair> &PairableInstUserPairSet,
DenseMap<Value *, Value *> &ChosenPairs,
DenseMap<ValuePair, size_t> &DAG,
DenseSet<ValuePair> &PrunedDAG, ValuePair J,
bool UseCycleCheck) {
SmallVector<ValuePairWithDepth, 32> Q;
// General depth-first post-order traversal:
Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
do {
ValuePairWithDepth QTop = Q.pop_back_val();
PrunedDAG.insert(QTop.first);
// Visit each child, pruning as necessary...
SmallVector<ValuePairWithDepth, 8> BestChildren;
DenseMap<ValuePair, std::vector<ValuePair> >::iterator QQ =
ConnectedPairs.find(QTop.first);
if (QQ == ConnectedPairs.end())
continue;
for (std::vector<ValuePair>::iterator K = QQ->second.begin(),
KE = QQ->second.end(); K != KE; ++K) {
DenseMap<ValuePair, size_t>::iterator C = DAG.find(*K);
if (C == DAG.end()) continue;
// This child is in the DAG, now we need to make sure it is the
// best of any conflicting children. There could be multiple
// conflicting children, so first, determine if we're keeping
// this child, then delete conflicting children as necessary.
// It is also necessary to guard against pairing-induced
// dependencies. Consider instructions a .. x .. y .. b
// such that (a,b) are to be fused and (x,y) are to be fused
// but a is an input to x and b is an output from y. This
// means that y cannot be moved after b but x must be moved
// after b for (a,b) to be fused. In other words, after
// fusing (a,b) we have y .. a/b .. x where y is an input
// to a/b and x is an output to a/b: x and y can no longer
// be legally fused. To prevent this condition, we must
// make sure that a child pair added to the DAG is not
// both an input and output of an already-selected pair.
// Pairing-induced dependencies can also form from more complicated
// cycles. The pair vs. pair conflicts are easy to check, and so
// that is done explicitly for "fast rejection", and because for
// child vs. child conflicts, we may prefer to keep the current
// pair in preference to the already-selected child.
DenseSet<ValuePair> CurrentPairs;
bool CanAdd = true;
for (SmallVectorImpl<ValuePairWithDepth>::iterator C2
= BestChildren.begin(), E2 = BestChildren.end();
C2 != E2; ++C2) {
if (C2->first.first == C->first.first ||
C2->first.first == C->first.second ||
C2->first.second == C->first.first ||
C2->first.second == C->first.second ||
pairsConflict(C2->first, C->first, PairableInstUsers,
UseCycleCheck ? &PairableInstUserMap : nullptr,
UseCycleCheck ? &PairableInstUserPairSet
: nullptr)) {
if (C2->second >= C->second) {
CanAdd = false;
break;
}
CurrentPairs.insert(C2->first);
}
}
if (!CanAdd) continue;
// Even worse, this child could conflict with another node already
// selected for the DAG. If that is the case, ignore this child.
for (DenseSet<ValuePair>::iterator T = PrunedDAG.begin(),
E2 = PrunedDAG.end(); T != E2; ++T) {
if (T->first == C->first.first ||
T->first == C->first.second ||
T->second == C->first.first ||
T->second == C->first.second ||
pairsConflict(*T, C->first, PairableInstUsers,
UseCycleCheck ? &PairableInstUserMap : nullptr,
UseCycleCheck ? &PairableInstUserPairSet
: nullptr)) {
CanAdd = false;
break;
}
CurrentPairs.insert(*T);
}
if (!CanAdd) continue;
// And check the queue too...
for (SmallVectorImpl<ValuePairWithDepth>::iterator C2 = Q.begin(),
E2 = Q.end(); C2 != E2; ++C2) {
if (C2->first.first == C->first.first ||
C2->first.first == C->first.second ||
C2->first.second == C->first.first ||
C2->first.second == C->first.second ||
pairsConflict(C2->first, C->first, PairableInstUsers,
UseCycleCheck ? &PairableInstUserMap : nullptr,
UseCycleCheck ? &PairableInstUserPairSet
: nullptr)) {
CanAdd = false;
break;
}
CurrentPairs.insert(C2->first);
}
if (!CanAdd) continue;
// Last but not least, check for a conflict with any of the
// already-chosen pairs.
for (DenseMap<Value *, Value *>::iterator C2 =
ChosenPairs.begin(), E2 = ChosenPairs.end();
C2 != E2; ++C2) {
if (pairsConflict(*C2, C->first, PairableInstUsers,
UseCycleCheck ? &PairableInstUserMap : nullptr,
UseCycleCheck ? &PairableInstUserPairSet
: nullptr)) {
CanAdd = false;
break;
}
CurrentPairs.insert(*C2);
}
if (!CanAdd) continue;
// To check for non-trivial cycles formed by the addition of the
// current pair we've formed a list of all relevant pairs, now use a
// graph walk to check for a cycle. We start from the current pair and
// walk the use dag to see if we again reach the current pair. If we
// do, then the current pair is rejected.
// FIXME: It may be more efficient to use a topological-ordering
// algorithm to improve the cycle check. This should be investigated.
if (UseCycleCheck &&
pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs))
continue;
// This child can be added, but we may have chosen it in preference
// to an already-selected child. Check for this here, and if a
// conflict is found, then remove the previously-selected child
// before adding this one in its place.
for (SmallVectorImpl<ValuePairWithDepth>::iterator C2
= BestChildren.begin(); C2 != BestChildren.end();) {
if (C2->first.first == C->first.first ||
C2->first.first == C->first.second ||
C2->first.second == C->first.first ||
C2->first.second == C->first.second ||
pairsConflict(C2->first, C->first, PairableInstUsers))
C2 = BestChildren.erase(C2);
else
++C2;
}
BestChildren.push_back(ValuePairWithDepth(C->first, C->second));
}
for (SmallVectorImpl<ValuePairWithDepth>::iterator C
= BestChildren.begin(), E2 = BestChildren.end();
C != E2; ++C) {
size_t DepthF = getDepthFactor(C->first.first);
Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF));
}
} while (!Q.empty());
}
// This function finds the best dag of mututally-compatible connected
// pairs, given the choice of root pairs as an iterator range.
void BBVectorize::findBestDAGFor(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
DenseMap<ValuePair, int> &CandidatePairCostSavings,
std::vector<Value *> &PairableInsts,
DenseSet<ValuePair> &FixedOrderPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
DenseSet<VPPair> &PairableInstUserPairSet,
DenseMap<Value *, Value *> &ChosenPairs,
DenseSet<ValuePair> &BestDAG, size_t &BestMaxDepth,
int &BestEffSize, Value *II, std::vector<Value *>&JJ,
bool UseCycleCheck) {
for (std::vector<Value *>::iterator J = JJ.begin(), JE = JJ.end();
J != JE; ++J) {
ValuePair IJ(II, *J);
if (!CandidatePairsSet.count(IJ))
continue;
// Before going any further, make sure that this pair does not
// conflict with any already-selected pairs (see comment below
// near the DAG pruning for more details).
DenseSet<ValuePair> ChosenPairSet;
bool DoesConflict = false;
for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(),
E = ChosenPairs.end(); C != E; ++C) {
if (pairsConflict(*C, IJ, PairableInstUsers,
UseCycleCheck ? &PairableInstUserMap : nullptr,
UseCycleCheck ? &PairableInstUserPairSet : nullptr)) {
DoesConflict = true;
break;
}
ChosenPairSet.insert(*C);
}
if (DoesConflict) continue;
if (UseCycleCheck &&
pairWillFormCycle(IJ, PairableInstUserMap, ChosenPairSet))
continue;
DenseMap<ValuePair, size_t> DAG;
buildInitialDAGFor(CandidatePairs, CandidatePairsSet,
PairableInsts, ConnectedPairs,
PairableInstUsers, ChosenPairs, DAG, IJ);
// Because we'll keep the child with the largest depth, the largest
// depth is still the same in the unpruned DAG.
size_t MaxDepth = DAG.lookup(IJ);
DEBUG(if (DebugPairSelection) dbgs() << "BBV: found DAG for pair {"
<< *IJ.first << " <-> " << *IJ.second << "} of depth " <<
MaxDepth << " and size " << DAG.size() << "\n");
// At this point the DAG has been constructed, but, may contain
// contradictory children (meaning that different children of
// some dag node may be attempting to fuse the same instruction).
// So now we walk the dag again, in the case of a conflict,
// keep only the child with the largest depth. To break a tie,
// favor the first child.
DenseSet<ValuePair> PrunedDAG;
pruneDAGFor(CandidatePairs, PairableInsts, ConnectedPairs,
PairableInstUsers, PairableInstUserMap,
PairableInstUserPairSet,
ChosenPairs, DAG, PrunedDAG, IJ, UseCycleCheck);
int EffSize = 0;
if (TTI) {
DenseSet<Value *> PrunedDAGInstrs;
for (DenseSet<ValuePair>::iterator S = PrunedDAG.begin(),
E = PrunedDAG.end(); S != E; ++S) {
PrunedDAGInstrs.insert(S->first);
PrunedDAGInstrs.insert(S->second);
}
// The set of pairs that have already contributed to the total cost.
DenseSet<ValuePair> IncomingPairs;
// If the cost model were perfect, this might not be necessary; but we
// need to make sure that we don't get stuck vectorizing our own
// shuffle chains.
bool HasNontrivialInsts = false;
// The node weights represent the cost savings associated with
// fusing the pair of instructions.
for (DenseSet<ValuePair>::iterator S = PrunedDAG.begin(),
E = PrunedDAG.end(); S != E; ++S) {
if (!isa<ShuffleVectorInst>(S->first) &&
!isa<InsertElementInst>(S->first) &&
!isa<ExtractElementInst>(S->first))
HasNontrivialInsts = true;
bool FlipOrder = false;
if (getDepthFactor(S->first)) {
int ESContrib = CandidatePairCostSavings.find(*S)->second;
DEBUG(if (DebugPairSelection) dbgs() << "\tweight {"
<< *S->first << " <-> " << *S->second << "} = " <<
ESContrib << "\n");
EffSize += ESContrib;
}
// The edge weights contribute in a negative sense: they represent
// the cost of shuffles.
DenseMap<ValuePair, std::vector<ValuePair> >::iterator SS =
ConnectedPairDeps.find(*S);
if (SS != ConnectedPairDeps.end()) {
unsigned NumDepsDirect = 0, NumDepsSwap = 0;
for (std::vector<ValuePair>::iterator T = SS->second.begin(),
TE = SS->second.end(); T != TE; ++T) {
VPPair Q(*S, *T);
if (!PrunedDAG.count(Q.second))
continue;
DenseMap<VPPair, unsigned>::iterator R =
PairConnectionTypes.find(VPPair(Q.second, Q.first));
assert(R != PairConnectionTypes.end() &&
"Cannot find pair connection type");
if (R->second == PairConnectionDirect)
++NumDepsDirect;
else if (R->second == PairConnectionSwap)
++NumDepsSwap;
}
// If there are more swaps than direct connections, then
// the pair order will be flipped during fusion. So the real
// number of swaps is the minimum number.
FlipOrder = !FixedOrderPairs.count(*S) &&
((NumDepsSwap > NumDepsDirect) ||
FixedOrderPairs.count(ValuePair(S->second, S->first)));
for (std::vector<ValuePair>::iterator T = SS->second.begin(),
TE = SS->second.end(); T != TE; ++T) {
VPPair Q(*S, *T);
if (!PrunedDAG.count(Q.second))
continue;
DenseMap<VPPair, unsigned>::iterator R =
PairConnectionTypes.find(VPPair(Q.second, Q.first));
assert(R != PairConnectionTypes.end() &&
"Cannot find pair connection type");
Type *Ty1 = Q.second.first->getType(),
*Ty2 = Q.second.second->getType();
Type *VTy = getVecTypeForPair(Ty1, Ty2);
if ((R->second == PairConnectionDirect && FlipOrder) ||
(R->second == PairConnectionSwap && !FlipOrder) ||
R->second == PairConnectionSplat) {
int ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
VTy, VTy);
if (VTy->getVectorNumElements() == 2) {
if (R->second == PairConnectionSplat)
ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
TargetTransformInfo::SK_Broadcast, VTy));
else
ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
TargetTransformInfo::SK_Reverse, VTy));
}
DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
*Q.second.first << " <-> " << *Q.second.second <<
"} -> {" <<
*S->first << " <-> " << *S->second << "} = " <<
ESContrib << "\n");
EffSize -= ESContrib;
}
}
}
// Compute the cost of outgoing edges. We assume that edges outgoing
// to shuffles, inserts or extracts can be merged, and so contribute
// no additional cost.
if (!S->first->getType()->isVoidTy()) {
Type *Ty1 = S->first->getType(),
*Ty2 = S->second->getType();
Type *VTy = getVecTypeForPair(Ty1, Ty2);
bool NeedsExtraction = false;
for (User *U : S->first->users()) {
if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(U)) {
// Shuffle can be folded if it has no other input
if (isa<UndefValue>(SI->getOperand(1)))
continue;
}
if (isa<ExtractElementInst>(U))
continue;
if (PrunedDAGInstrs.count(U))
continue;
NeedsExtraction = true;
break;
}
if (NeedsExtraction) {
int ESContrib;
if (Ty1->isVectorTy()) {
ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
Ty1, VTy);
ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
TargetTransformInfo::SK_ExtractSubvector, VTy, 0, Ty1));
} else
ESContrib = (int) TTI->getVectorInstrCost(
Instruction::ExtractElement, VTy, 0);
DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
*S->first << "} = " << ESContrib << "\n");
EffSize -= ESContrib;
}
NeedsExtraction = false;
for (User *U : S->second->users()) {
if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(U)) {
// Shuffle can be folded if it has no other input
if (isa<UndefValue>(SI->getOperand(1)))
continue;
}
if (isa<ExtractElementInst>(U))
continue;
if (PrunedDAGInstrs.count(U))
continue;
NeedsExtraction = true;
break;
}
if (NeedsExtraction) {
int ESContrib;
if (Ty2->isVectorTy()) {
ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
Ty2, VTy);
ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
TargetTransformInfo::SK_ExtractSubvector, VTy,
Ty1->isVectorTy() ? Ty1->getVectorNumElements() : 1, Ty2));
} else
ESContrib = (int) TTI->getVectorInstrCost(
Instruction::ExtractElement, VTy, 1);
DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
*S->second << "} = " << ESContrib << "\n");
EffSize -= ESContrib;
}
}
// Compute the cost of incoming edges.
if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) {
Instruction *S1 = cast<Instruction>(S->first),
*S2 = cast<Instruction>(S->second);
for (unsigned o = 0; o < S1->getNumOperands(); ++o) {
Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o);
// Combining constants into vector constants (or small vector
// constants into larger ones are assumed free).
if (isa<Constant>(O1) && isa<Constant>(O2))
continue;
if (FlipOrder)
std::swap(O1, O2);
ValuePair VP = ValuePair(O1, O2);
ValuePair VPR = ValuePair(O2, O1);
// Internal edges are not handled here.
if (PrunedDAG.count(VP) || PrunedDAG.count(VPR))
continue;
Type *Ty1 = O1->getType(),
*Ty2 = O2->getType();
Type *VTy = getVecTypeForPair(Ty1, Ty2);
// Combining vector operations of the same type is also assumed
// folded with other operations.
if (Ty1 == Ty2) {
// If both are insert elements, then both can be widened.
InsertElementInst *IEO1 = dyn_cast<InsertElementInst>(O1),
*IEO2 = dyn_cast<InsertElementInst>(O2);
if (IEO1 && IEO2 && isPureIEChain(IEO1) && isPureIEChain(IEO2))
continue;
// If both are extract elements, and both have the same input
// type, then they can be replaced with a shuffle
ExtractElementInst *EIO1 = dyn_cast<ExtractElementInst>(O1),
*EIO2 = dyn_cast<ExtractElementInst>(O2);
if (EIO1 && EIO2 &&
EIO1->getOperand(0)->getType() ==
EIO2->getOperand(0)->getType())
continue;
// If both are a shuffle with equal operand types and only two
// unqiue operands, then they can be replaced with a single
// shuffle
ShuffleVectorInst *SIO1 = dyn_cast<ShuffleVectorInst>(O1),
*SIO2 = dyn_cast<ShuffleVectorInst>(O2);
if (SIO1 && SIO2 &&
SIO1->getOperand(0)->getType() ==
SIO2->getOperand(0)->getType()) {
SmallSet<Value *, 4> SIOps;
SIOps.insert(SIO1->getOperand(0));
SIOps.insert(SIO1->getOperand(1));
SIOps.insert(SIO2->getOperand(0));
SIOps.insert(SIO2->getOperand(1));
if (SIOps.size() <= 2)
continue;
}
}
int ESContrib;
// This pair has already been formed.
if (IncomingPairs.count(VP)) {
continue;
} else if (IncomingPairs.count(VPR)) {
ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
VTy, VTy);
if (VTy->getVectorNumElements() == 2)
ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
TargetTransformInfo::SK_Reverse, VTy));
} else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) {
ESContrib = (int) TTI->getVectorInstrCost(
Instruction::InsertElement, VTy, 0);
ESContrib += (int) TTI->getVectorInstrCost(
Instruction::InsertElement, VTy, 1);
} else if (!Ty1->isVectorTy()) {
// O1 needs to be inserted into a vector of size O2, and then
// both need to be shuffled together.
ESContrib = (int) TTI->getVectorInstrCost(
Instruction::InsertElement, Ty2, 0);
ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
VTy, Ty2);
} else if (!Ty2->isVectorTy()) {
// O2 needs to be inserted into a vector of size O1, and then
// both need to be shuffled together.
ESContrib = (int) TTI->getVectorInstrCost(
Instruction::InsertElement, Ty1, 0);
ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
VTy, Ty1);
} else {
Type *TyBig = Ty1, *TySmall = Ty2;
if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements())
std::swap(TyBig, TySmall);
ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
VTy, TyBig);
if (TyBig != TySmall)
ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
TyBig, TySmall);
}
DEBUG(if (DebugPairSelection) dbgs() << "\tcost {"
<< *O1 << " <-> " << *O2 << "} = " <<
ESContrib << "\n");
EffSize -= ESContrib;
IncomingPairs.insert(VP);
}
}
}
if (!HasNontrivialInsts) {
DEBUG(if (DebugPairSelection) dbgs() <<
"\tNo non-trivial instructions in DAG;"
" override to zero effective size\n");
EffSize = 0;
}
} else {
for (DenseSet<ValuePair>::iterator S = PrunedDAG.begin(),
E = PrunedDAG.end(); S != E; ++S)
EffSize += (int) getDepthFactor(S->first);
}
DEBUG(if (DebugPairSelection)
dbgs() << "BBV: found pruned DAG for pair {"
<< *IJ.first << " <-> " << *IJ.second << "} of depth " <<
MaxDepth << " and size " << PrunedDAG.size() <<
" (effective size: " << EffSize << ")\n");
if (((TTI && !UseChainDepthWithTI) ||
MaxDepth >= Config.ReqChainDepth) &&
EffSize > 0 && EffSize > BestEffSize) {
BestMaxDepth = MaxDepth;
BestEffSize = EffSize;
BestDAG = PrunedDAG;
}
}
}
// Given the list of candidate pairs, this function selects those
// that will be fused into vector instructions.
void BBVectorize::choosePairs(
DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
DenseSet<ValuePair> &CandidatePairsSet,
DenseMap<ValuePair, int> &CandidatePairCostSavings,
std::vector<Value *> &PairableInsts,
DenseSet<ValuePair> &FixedOrderPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps,
DenseSet<ValuePair> &PairableInstUsers,
DenseMap<Value *, Value *>& ChosenPairs) {
bool UseCycleCheck =
CandidatePairsSet.size() <= Config.MaxCandPairsForCycleCheck;
DenseMap<Value *, std::vector<Value *> > CandidatePairs2;
for (DenseSet<ValuePair>::iterator I = CandidatePairsSet.begin(),
E = CandidatePairsSet.end(); I != E; ++I) {
std::vector<Value *> &JJ = CandidatePairs2[I->second];
if (JJ.empty()) JJ.reserve(32);
JJ.push_back(I->first);
}
DenseMap<ValuePair, std::vector<ValuePair> > PairableInstUserMap;
DenseSet<VPPair> PairableInstUserPairSet;
for (std::vector<Value *>::iterator I = PairableInsts.begin(),
E = PairableInsts.end(); I != E; ++I) {
// The number of possible pairings for this variable:
size_t NumChoices = CandidatePairs.lookup(*I).size();
if (!NumChoices) continue;
std::vector<Value *> &JJ = CandidatePairs[*I];
// The best pair to choose and its dag:
size_t BestMaxDepth = 0;
int BestEffSize = 0;
DenseSet<ValuePair> BestDAG;
findBestDAGFor(CandidatePairs, CandidatePairsSet,
CandidatePairCostSavings,
PairableInsts, FixedOrderPairs, PairConnectionTypes,
ConnectedPairs, ConnectedPairDeps,
PairableInstUsers, PairableInstUserMap,
PairableInstUserPairSet, ChosenPairs,
BestDAG, BestMaxDepth, BestEffSize, *I, JJ,
UseCycleCheck);
if (BestDAG.empty())
continue;
// A dag has been chosen (or not) at this point. If no dag was
// chosen, then this instruction, I, cannot be paired (and is no longer
// considered).
DEBUG(dbgs() << "BBV: selected pairs in the best DAG for: "
<< *cast<Instruction>(*I) << "\n");
for (DenseSet<ValuePair>::iterator S = BestDAG.begin(),
SE2 = BestDAG.end(); S != SE2; ++S) {
// Insert the members of this dag into the list of chosen pairs.
ChosenPairs.insert(ValuePair(S->first, S->second));
DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " <<
*S->second << "\n");
// Remove all candidate pairs that have values in the chosen dag.
std::vector<Value *> &KK = CandidatePairs[S->first];
for (std::vector<Value *>::iterator K = KK.begin(), KE = KK.end();
K != KE; ++K) {
if (*K == S->second)
continue;
CandidatePairsSet.erase(ValuePair(S->first, *K));
}
std::vector<Value *> &LL = CandidatePairs2[S->second];
for (std::vector<Value *>::iterator L = LL.begin(), LE = LL.end();
L != LE; ++L) {
if (*L == S->first)
continue;
CandidatePairsSet.erase(ValuePair(*L, S->second));
}
std::vector<Value *> &MM = CandidatePairs[S->second];
for (std::vector<Value *>::iterator M = MM.begin(), ME = MM.end();
M != ME; ++M) {
assert(*M != S->first && "Flipped pair in candidate list?");
CandidatePairsSet.erase(ValuePair(S->second, *M));
}
std::vector<Value *> &NN = CandidatePairs2[S->first];
for (std::vector<Value *>::iterator N = NN.begin(), NE = NN.end();
N != NE; ++N) {
assert(*N != S->second && "Flipped pair in candidate list?");
CandidatePairsSet.erase(ValuePair(*N, S->first));
}
}
}
DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n");
}
std::string getReplacementName(Instruction *I, bool IsInput, unsigned o,
unsigned n = 0) {
if (!I->hasName())
return "";
return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) +
(n > 0 ? "." + utostr(n) : "")).str();
}
// Returns the value that is to be used as the pointer input to the vector
// instruction that fuses I with J.
Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context,
Instruction *I, Instruction *J, unsigned o) {
Value *IPtr, *JPtr;
unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
int64_t OffsetInElmts;
// Note: the analysis might fail here, that is why the pair order has
// been precomputed (OffsetInElmts must be unused here).
(void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
IAddressSpace, JAddressSpace,
OffsetInElmts, false);
// The pointer value is taken to be the one with the lowest offset.
Value *VPtr = IPtr;
Type *ArgTypeI = IPtr->getType()->getPointerElementType();
Type *ArgTypeJ = JPtr->getType()->getPointerElementType();
Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
Type *VArgPtrType
= PointerType::get(VArgType,
IPtr->getType()->getPointerAddressSpace());
return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o),
/* insert before */ I);
}
void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J,
unsigned MaskOffset, unsigned NumInElem,
unsigned NumInElem1, unsigned IdxOffset,
std::vector<Constant*> &Mask) {
unsigned NumElem1 = J->getType()->getVectorNumElements();
for (unsigned v = 0; v < NumElem1; ++v) {
int m = cast<ShuffleVectorInst>(J)->getMaskValue(v);
if (m < 0) {
Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context));
} else {
unsigned mm = m + (int) IdxOffset;
if (m >= (int) NumInElem1)
mm += (int) NumInElem;
Mask[v+MaskOffset] =
ConstantInt::get(Type::getInt32Ty(Context), mm);
}
}
}
// Returns the value that is to be used as the vector-shuffle mask to the
// vector instruction that fuses I with J.
Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context,
Instruction *I, Instruction *J) {
// This is the shuffle mask. We need to append the second
// mask to the first, and the numbers need to be adjusted.
Type *ArgTypeI = I->getType();
Type *ArgTypeJ = J->getType();
Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
unsigned NumElemI = ArgTypeI->getVectorNumElements();
// Get the total number of elements in the fused vector type.
// By definition, this must equal the number of elements in
// the final mask.
unsigned NumElem = VArgType->getVectorNumElements();
std::vector<Constant*> Mask(NumElem);
Type *OpTypeI = I->getOperand(0)->getType();
unsigned NumInElemI = OpTypeI->getVectorNumElements();
Type *OpTypeJ = J->getOperand(0)->getType();
unsigned NumInElemJ = OpTypeJ->getVectorNumElements();
// The fused vector will be:
// -----------------------------------------------------
// | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ |
// -----------------------------------------------------
// from which we'll extract NumElem total elements (where the first NumElemI
// of them come from the mask in I and the remainder come from the mask
// in J.
// For the mask from the first pair...
fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI,
0, Mask);
// For the mask from the second pair...
fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ,
NumInElemI, Mask);
return ConstantVector::get(Mask);
}
bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I,
Instruction *J, unsigned o, Value *&LOp,
unsigned numElemL,
Type *ArgTypeL, Type *ArgTypeH,
bool IBeforeJ, unsigned IdxOff) {
bool ExpandedIEChain = false;
if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) {
// If we have a pure insertelement chain, then this can be rewritten
// into a chain that directly builds the larger type.
if (isPureIEChain(LIE)) {
SmallVector<Value *, 8> VectElemts(numElemL,
UndefValue::get(ArgTypeL->getScalarType()));
InsertElementInst *LIENext = LIE;
do {
unsigned Idx =
cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue();
VectElemts[Idx] = LIENext->getOperand(1);
} while ((LIENext =
dyn_cast<InsertElementInst>(LIENext->getOperand(0))));
LIENext = nullptr;
Value *LIEPrev = UndefValue::get(ArgTypeH);
for (unsigned i = 0; i < numElemL; ++i) {
if (isa<UndefValue>(VectElemts[i])) continue;
LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i],
ConstantInt::get(Type::getInt32Ty(Context),
i + IdxOff),
getReplacementName(IBeforeJ ? I : J,
true, o, i+1));
LIENext->insertBefore(IBeforeJ ? J : I);
LIEPrev = LIENext;
}
LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH);
ExpandedIEChain = true;
}
}
return ExpandedIEChain;
}
static unsigned getNumScalarElements(Type *Ty) {
if (VectorType *VecTy = dyn_cast<VectorType>(Ty))
return VecTy->getNumElements();
return 1;
}
// Returns the value to be used as the specified operand of the vector
// instruction that fuses I with J.
Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I,
Instruction *J, unsigned o, bool IBeforeJ) {
Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
// Compute the fused vector type for this operand
Type *ArgTypeI = I->getOperand(o)->getType();
Type *ArgTypeJ = J->getOperand(o)->getType();
VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
Instruction *L = I, *H = J;
Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ;
unsigned numElemL = getNumScalarElements(ArgTypeL);
unsigned numElemH = getNumScalarElements(ArgTypeH);
Value *LOp = L->getOperand(o);
Value *HOp = H->getOperand(o);
unsigned numElem = VArgType->getNumElements();
// First, we check if we can reuse the "original" vector outputs (if these
// exist). We might need a shuffle.
ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp);
ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp);
ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp);
ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp);
// FIXME: If we're fusing shuffle instructions, then we can't apply this
// optimization. The input vectors to the shuffle might be a different
// length from the shuffle outputs. Unfortunately, the replacement
// shuffle mask has already been formed, and the mask entries are sensitive
// to the sizes of the inputs.
bool IsSizeChangeShuffle =
isa<ShuffleVectorInst>(L) &&
(LOp->getType() != L->getType() || HOp->getType() != H->getType());
if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) {
// We can have at most two unique vector inputs.
bool CanUseInputs = true;
Value *I1, *I2 = nullptr;
if (LEE) {
I1 = LEE->getOperand(0);
} else {
I1 = LSV->getOperand(0);
I2 = LSV->getOperand(1);
if (I2 == I1 || isa<UndefValue>(I2))
I2 = nullptr;
}
if (HEE) {
Value *I3 = HEE->getOperand(0);
if (!I2 && I3 != I1)
I2 = I3;
else if (I3 != I1 && I3 != I2)
CanUseInputs = false;
} else {
Value *I3 = HSV->getOperand(0);
if (!I2 && I3 != I1)
I2 = I3;
else if (I3 != I1 && I3 != I2)
CanUseInputs = false;
if (CanUseInputs) {
Value *I4 = HSV->getOperand(1);
if (!isa<UndefValue>(I4)) {
if (!I2 && I4 != I1)
I2 = I4;
else if (I4 != I1 && I4 != I2)
CanUseInputs = false;
}
}
}
if (CanUseInputs) {
unsigned LOpElem =
cast<Instruction>(LOp)->getOperand(0)->getType()
->getVectorNumElements();
unsigned HOpElem =
cast<Instruction>(HOp)->getOperand(0)->getType()
->getVectorNumElements();
// We have one or two input vectors. We need to map each index of the
// operands to the index of the original vector.
SmallVector<std::pair<int, int>, 8> II(numElem);
for (unsigned i = 0; i < numElemL; ++i) {
int Idx, INum;
if (LEE) {
Idx =
cast<ConstantInt>(LEE->getOperand(1))->getSExtValue();
INum = LEE->getOperand(0) == I1 ? 0 : 1;
} else {
Idx = LSV->getMaskValue(i);
if (Idx < (int) LOpElem) {
INum = LSV->getOperand(0) == I1 ? 0 : 1;
} else {
Idx -= LOpElem;
INum = LSV->getOperand(1) == I1 ? 0 : 1;
}
}
II[i] = std::pair<int, int>(Idx, INum);
}
for (unsigned i = 0; i < numElemH; ++i) {
int Idx, INum;
if (HEE) {
Idx =
cast<ConstantInt>(HEE->getOperand(1))->getSExtValue();
INum = HEE->getOperand(0) == I1 ? 0 : 1;
} else {
Idx = HSV->getMaskValue(i);
if (Idx < (int) HOpElem) {
INum = HSV->getOperand(0) == I1 ? 0 : 1;
} else {
Idx -= HOpElem;
INum = HSV->getOperand(1) == I1 ? 0 : 1;
}
}
II[i + numElemL] = std::pair<int, int>(Idx, INum);
}
// We now have an array which tells us from which index of which
// input vector each element of the operand comes.
VectorType *I1T = cast<VectorType>(I1->getType());
unsigned I1Elem = I1T->getNumElements();
if (!I2) {
// In this case there is only one underlying vector input. Check for
// the trivial case where we can use the input directly.
if (I1Elem == numElem) {
bool ElemInOrder = true;
for (unsigned i = 0; i < numElem; ++i) {
if (II[i].first != (int) i && II[i].first != -1) {
ElemInOrder = false;
break;
}
}
if (ElemInOrder)
return I1;
}
// A shuffle is needed.
std::vector<Constant *> Mask(numElem);
for (unsigned i = 0; i < numElem; ++i) {
int Idx = II[i].first;
if (Idx == -1)
Mask[i] = UndefValue::get(Type::getInt32Ty(Context));
else
Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
}
Instruction *S =
new ShuffleVectorInst(I1, UndefValue::get(I1T),
ConstantVector::get(Mask),
getReplacementName(IBeforeJ ? I : J,
true, o));
S->insertBefore(IBeforeJ ? J : I);
return S;
}
VectorType *I2T = cast<VectorType>(I2->getType());
unsigned I2Elem = I2T->getNumElements();
// This input comes from two distinct vectors. The first step is to
// make sure that both vectors are the same length. If not, the
// smaller one will need to grow before they can be shuffled together.
if (I1Elem < I2Elem) {
std::vector<Constant *> Mask(I2Elem);
unsigned v = 0;
for (; v < I1Elem; ++v)
Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
for (; v < I2Elem; ++v)
Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
Instruction *NewI1 =
new ShuffleVectorInst(I1, UndefValue::get(I1T),
ConstantVector::get(Mask),
getReplacementName(IBeforeJ ? I : J,
true, o, 1));
NewI1->insertBefore(IBeforeJ ? J : I);
I1 = NewI1;
I1Elem = I2Elem;
} else if (I1Elem > I2Elem) {
std::vector<Constant *> Mask(I1Elem);
unsigned v = 0;
for (; v < I2Elem; ++v)
Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
for (; v < I1Elem; ++v)
Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
Instruction *NewI2 =
new ShuffleVectorInst(I2, UndefValue::get(I2T),
ConstantVector::get(Mask),
getReplacementName(IBeforeJ ? I : J,
true, o, 1));
NewI2->insertBefore(IBeforeJ ? J : I);
I2 = NewI2;
}
// Now that both I1 and I2 are the same length we can shuffle them
// together (and use the result).
std::vector<Constant *> Mask(numElem);
for (unsigned v = 0; v < numElem; ++v) {
if (II[v].first == -1) {
Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
} else {
int Idx = II[v].first + II[v].second * I1Elem;
Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
}
}
Instruction *NewOp =
new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask),
getReplacementName(IBeforeJ ? I : J, true, o));
NewOp->insertBefore(IBeforeJ ? J : I);
return NewOp;
}
}
Type *ArgType = ArgTypeL;
if (numElemL < numElemH) {
if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH,
ArgTypeL, VArgType, IBeforeJ, 1)) {
// This is another short-circuit case: we're combining a scalar into
// a vector that is formed by an IE chain. We've just expanded the IE
// chain, now insert the scalar and we're done.
Instruction *S = InsertElementInst::Create(HOp, LOp, CV0,
getReplacementName(IBeforeJ ? I : J, true, o));
S->insertBefore(IBeforeJ ? J : I);
return S;
} else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL,
ArgTypeH, IBeforeJ)) {
// The two vector inputs to the shuffle must be the same length,
// so extend the smaller vector to be the same length as the larger one.
Instruction *NLOp;
if (numElemL > 1) {
std::vector<Constant *> Mask(numElemH);
unsigned v = 0;
for (; v < numElemL; ++v)
Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
for (; v < numElemH; ++v)
Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL),
ConstantVector::get(Mask),
getReplacementName(IBeforeJ ? I : J,
true, o, 1));
} else {
NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0,
getReplacementName(IBeforeJ ? I : J,
true, o, 1));
}
NLOp->insertBefore(IBeforeJ ? J : I);
LOp = NLOp;
}
ArgType = ArgTypeH;
} else if (numElemL > numElemH) {
if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL,
ArgTypeH, VArgType, IBeforeJ)) {
Instruction *S =
InsertElementInst::Create(LOp, HOp,
ConstantInt::get(Type::getInt32Ty(Context),
numElemL),
getReplacementName(IBeforeJ ? I : J,
true, o));
S->insertBefore(IBeforeJ ? J : I);
return S;
} else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH,
ArgTypeL, IBeforeJ)) {
Instruction *NHOp;
if (numElemH > 1) {
std::vector<Constant *> Mask(numElemL);
unsigned v = 0;
for (; v < numElemH; ++v)
Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
for (; v < numElemL; ++v)
Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH),
ConstantVector::get(Mask),
getReplacementName(IBeforeJ ? I : J,
true, o, 1));
} else {
NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0,
getReplacementName(IBeforeJ ? I : J,
true, o, 1));
}
NHOp->insertBefore(IBeforeJ ? J : I);
HOp = NHOp;
}
}
if (ArgType->isVectorTy()) {
unsigned numElem = VArgType->getVectorNumElements();
std::vector<Constant*> Mask(numElem);
for (unsigned v = 0; v < numElem; ++v) {
unsigned Idx = v;
// If the low vector was expanded, we need to skip the extra
// undefined entries.
if (v >= numElemL && numElemH > numElemL)
Idx += (numElemH - numElemL);
Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
}
Instruction *BV = new ShuffleVectorInst(LOp, HOp,
ConstantVector::get(Mask),
getReplacementName(IBeforeJ ? I : J, true, o));
BV->insertBefore(IBeforeJ ? J : I);
return BV;
}
Instruction *BV1 = InsertElementInst::Create(
UndefValue::get(VArgType), LOp, CV0,
getReplacementName(IBeforeJ ? I : J,
true, o, 1));
BV1->insertBefore(IBeforeJ ? J : I);
Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1,
getReplacementName(IBeforeJ ? I : J,
true, o, 2));
BV2->insertBefore(IBeforeJ ? J : I);
return BV2;
}
// This function creates an array of values that will be used as the inputs
// to the vector instruction that fuses I with J.
void BBVectorize::getReplacementInputsForPair(LLVMContext& Context,
Instruction *I, Instruction *J,
SmallVectorImpl<Value *> &ReplacedOperands,
bool IBeforeJ) {
unsigned NumOperands = I->getNumOperands();
for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) {
// Iterate backward so that we look at the store pointer
// first and know whether or not we need to flip the inputs.
if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) {
// This is the pointer for a load/store instruction.
ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o);
continue;
} else if (isa<CallInst>(I)) {
Function *F = cast<CallInst>(I)->getCalledFunction();
Intrinsic::ID IID = F->getIntrinsicID();
if (o == NumOperands-1) {
BasicBlock &BB = *I->getParent();
Module *M = BB.getParent()->getParent();
Type *ArgTypeI = I->getType();
Type *ArgTypeJ = J->getType();
Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
ReplacedOperands[o] = Intrinsic::getDeclaration(M, IID, VArgType);
continue;
} else if ((IID == Intrinsic::powi || IID == Intrinsic::ctlz ||
IID == Intrinsic::cttz) && o == 1) {
// The second argument of powi/ctlz/cttz is a single integer/constant
// and we've already checked that both arguments are equal.
// As a result, we just keep I's second argument.
ReplacedOperands[o] = I->getOperand(o);
continue;
}
} else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) {
ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J);
continue;
}
ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ);
}
}
// This function creates two values that represent the outputs of the
// original I and J instructions. These are generally vector shuffles
// or extracts. In many cases, these will end up being unused and, thus,
// eliminated by later passes.
void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
Instruction *J, Instruction *K,
Instruction *&InsertionPt,
Instruction *&K1, Instruction *&K2) {
if (isa<StoreInst>(I))
return;
Type *IType = I->getType();
Type *JType = J->getType();
VectorType *VType = getVecTypeForPair(IType, JType);
unsigned numElem = VType->getNumElements();
unsigned numElemI = getNumScalarElements(IType);
unsigned numElemJ = getNumScalarElements(JType);
if (IType->isVectorTy()) {
std::vector<Constant *> Mask1(numElemI), Mask2(numElemI);
for (unsigned v = 0; v < numElemI; ++v) {
Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ + v);
}
K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
ConstantVector::get(Mask1),
getReplacementName(K, false, 1));
} else {
Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
K1 = ExtractElementInst::Create(K, CV0, getReplacementName(K, false, 1));
}
if (JType->isVectorTy()) {
std::vector<Constant *> Mask1(numElemJ), Mask2(numElemJ);
for (unsigned v = 0; v < numElemJ; ++v) {
Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI + v);
}
K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
ConstantVector::get(Mask2),
getReplacementName(K, false, 2));
} else {
Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem - 1);
K2 = ExtractElementInst::Create(K, CV1, getReplacementName(K, false, 2));
}
K1->insertAfter(K);
K2->insertAfter(K1);
InsertionPt = K2;
}
// Move all uses of the function I (including pairing-induced uses) after J.
bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB,
DenseSet<ValuePair> &LoadMoveSetPairs,
Instruction *I, Instruction *J) {
// Skip to the first instruction past I.
BasicBlock::iterator L = std::next(BasicBlock::iterator(I));
DenseSet<Value *> Users;
AliasSetTracker WriteSet(*AA);
if (I->mayWriteToMemory()) WriteSet.add(I);
for (; cast<Instruction>(L) != J; ++L)
(void)trackUsesOfI(Users, WriteSet, I, &*L, true, &LoadMoveSetPairs);
assert(cast<Instruction>(L) == J &&
"Tracking has not proceeded far enough to check for dependencies");
// If J is now in the use set of I, then trackUsesOfI will return true
// and we have a dependency cycle (and the fusing operation must abort).
return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSetPairs);
}
// Move all uses of the function I (including pairing-induced uses) after J.
void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB,
DenseSet<ValuePair> &LoadMoveSetPairs,
Instruction *&InsertionPt,
Instruction *I, Instruction *J) {
// Skip to the first instruction past I.
BasicBlock::iterator L = std::next(BasicBlock::iterator(I));
DenseSet<Value *> Users;
AliasSetTracker WriteSet(*AA);
if (I->mayWriteToMemory()) WriteSet.add(I);
for (; cast<Instruction>(L) != J;) {
if (trackUsesOfI(Users, WriteSet, I, &*L, true, &LoadMoveSetPairs)) {
// Move this instruction
Instruction *InstToMove = &*L++;
DEBUG(dbgs() << "BBV: moving: " << *InstToMove <<
" to after " << *InsertionPt << "\n");
InstToMove->removeFromParent();
InstToMove->insertAfter(InsertionPt);
InsertionPt = InstToMove;
} else {
++L;
}
}
}
// Collect all load instruction that are in the move set of a given first
// pair member. These loads depend on the first instruction, I, and so need
// to be moved after J (the second instruction) when the pair is fused.
void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB,
DenseMap<Value *, Value *> &ChosenPairs,
DenseMap<Value *, std::vector<Value *> > &LoadMoveSet,
DenseSet<ValuePair> &LoadMoveSetPairs,
Instruction *I) {
// Skip to the first instruction past I.
BasicBlock::iterator L = std::next(BasicBlock::iterator(I));
DenseSet<Value *> Users;
AliasSetTracker WriteSet(*AA);
if (I->mayWriteToMemory()) WriteSet.add(I);
// Note: We cannot end the loop when we reach J because J could be moved
// farther down the use chain by another instruction pairing. Also, J
// could be before I if this is an inverted input.
for (BasicBlock::iterator E = BB.end(); L != E; ++L) {
if (trackUsesOfI(Users, WriteSet, I, &*L)) {
if (L->mayReadFromMemory()) {
LoadMoveSet[&*L].push_back(I);
LoadMoveSetPairs.insert(ValuePair(&*L, I));
}
}
}
}
// In cases where both load/stores and the computation of their pointers
// are chosen for vectorization, we can end up in a situation where the
// aliasing analysis starts returning different query results as the
// process of fusing instruction pairs continues. Because the algorithm
// relies on finding the same use dags here as were found earlier, we'll
// need to precompute the necessary aliasing information here and then
// manually update it during the fusion process.
void BBVectorize::collectLoadMoveSet(BasicBlock &BB,
std::vector<Value *> &PairableInsts,
DenseMap<Value *, Value *> &ChosenPairs,
DenseMap<Value *, std::vector<Value *> > &LoadMoveSet,
DenseSet<ValuePair> &LoadMoveSetPairs) {
for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
PIE = PairableInsts.end(); PI != PIE; ++PI) {
DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI);
if (P == ChosenPairs.end()) continue;
Instruction *I = cast<Instruction>(P->first);
collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet,
LoadMoveSetPairs, I);
}
}
// This function fuses the chosen instruction pairs into vector instructions,
// taking care preserve any needed scalar outputs and, then, it reorders the
// remaining instructions as needed (users of the first member of the pair
// need to be moved to after the location of the second member of the pair
// because the vector instruction is inserted in the location of the pair's
// second member).
void BBVectorize::fuseChosenPairs(BasicBlock &BB,
std::vector<Value *> &PairableInsts,
DenseMap<Value *, Value *> &ChosenPairs,
DenseSet<ValuePair> &FixedOrderPairs,
DenseMap<VPPair, unsigned> &PairConnectionTypes,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps) {
LLVMContext& Context = BB.getContext();
// During the vectorization process, the order of the pairs to be fused
// could be flipped. So we'll add each pair, flipped, into the ChosenPairs
// list. After a pair is fused, the flipped pair is removed from the list.
DenseSet<ValuePair> FlippedPairs;
for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(),
E = ChosenPairs.end(); P != E; ++P)
FlippedPairs.insert(ValuePair(P->second, P->first));
for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(),
E = FlippedPairs.end(); P != E; ++P)
ChosenPairs.insert(*P);
DenseMap<Value *, std::vector<Value *> > LoadMoveSet;
DenseSet<ValuePair> LoadMoveSetPairs;
collectLoadMoveSet(BB, PairableInsts, ChosenPairs,
LoadMoveSet, LoadMoveSetPairs);
DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n");
for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) {
DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(&*PI);
if (P == ChosenPairs.end()) {
++PI;
continue;
}
if (getDepthFactor(P->first) == 0) {
// These instructions are not really fused, but are tracked as though
// they are. Any case in which it would be interesting to fuse them
// will be taken care of by InstCombine.
--NumFusedOps;
++PI;
continue;
}
Instruction *I = cast<Instruction>(P->first),
*J = cast<Instruction>(P->second);
DEBUG(dbgs() << "BBV: fusing: " << *I <<
" <-> " << *J << "\n");
// Remove the pair and flipped pair from the list.
DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second);
assert(FP != ChosenPairs.end() && "Flipped pair not found in list");
ChosenPairs.erase(FP);
ChosenPairs.erase(P);
if (!canMoveUsesOfIAfterJ(BB, LoadMoveSetPairs, I, J)) {
DEBUG(dbgs() << "BBV: fusion of: " << *I <<
" <-> " << *J <<
" aborted because of non-trivial dependency cycle\n");
--NumFusedOps;
++PI;
continue;
}
// If the pair must have the other order, then flip it.
bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I));
if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) {
// This pair does not have a fixed order, and so we might want to
// flip it if that will yield fewer shuffles. We count the number
// of dependencies connected via swaps, and those directly connected,
// and flip the order if the number of swaps is greater.
bool OrigOrder = true;
DenseMap<ValuePair, std::vector<ValuePair> >::iterator IJ =
ConnectedPairDeps.find(ValuePair(I, J));
if (IJ == ConnectedPairDeps.end()) {
IJ = ConnectedPairDeps.find(ValuePair(J, I));
OrigOrder = false;
}
if (IJ != ConnectedPairDeps.end()) {
unsigned NumDepsDirect = 0, NumDepsSwap = 0;
for (std::vector<ValuePair>::iterator T = IJ->second.begin(),
TE = IJ->second.end(); T != TE; ++T) {
VPPair Q(IJ->first, *T);
DenseMap<VPPair, unsigned>::iterator R =
PairConnectionTypes.find(VPPair(Q.second, Q.first));
assert(R != PairConnectionTypes.end() &&
"Cannot find pair connection type");
if (R->second == PairConnectionDirect)
++NumDepsDirect;
else if (R->second == PairConnectionSwap)
++NumDepsSwap;
}
if (!OrigOrder)
std::swap(NumDepsDirect, NumDepsSwap);
if (NumDepsSwap > NumDepsDirect) {
FlipPairOrder = true;
DEBUG(dbgs() << "BBV: reordering pair: " << *I <<
" <-> " << *J << "\n");
}
}
}
Instruction *L = I, *H = J;
if (FlipPairOrder)
std::swap(H, L);
// If the pair being fused uses the opposite order from that in the pair
// connection map, then we need to flip the types.
DenseMap<ValuePair, std::vector<ValuePair> >::iterator HL =
ConnectedPairs.find(ValuePair(H, L));
if (HL != ConnectedPairs.end())
for (std::vector<ValuePair>::iterator T = HL->second.begin(),
TE = HL->second.end(); T != TE; ++T) {
VPPair Q(HL->first, *T);
DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(Q);
assert(R != PairConnectionTypes.end() &&
"Cannot find pair connection type");
if (R->second == PairConnectionDirect)
R->second = PairConnectionSwap;
else if (R->second == PairConnectionSwap)
R->second = PairConnectionDirect;
}
bool LBeforeH = !FlipPairOrder;
unsigned NumOperands = I->getNumOperands();
SmallVector<Value *, 3> ReplacedOperands(NumOperands);
getReplacementInputsForPair(Context, L, H, ReplacedOperands,
LBeforeH);
// Make a copy of the original operation, change its type to the vector
// type and replace its operands with the vector operands.
Instruction *K = L->clone();
if (L->hasName())
K->takeName(L);
else if (H->hasName())
K->takeName(H);
if (auto CS = CallSite(K)) {
SmallVector<Type *, 3> Tys;
FunctionType *Old = CS.getFunctionType();
unsigned NumOld = Old->getNumParams();
assert(NumOld <= ReplacedOperands.size());
for (unsigned i = 0; i != NumOld; ++i)
Tys.push_back(ReplacedOperands[i]->getType());
CS.mutateFunctionType(
FunctionType::get(getVecTypeForPair(L->getType(), H->getType()),
Tys, Old->isVarArg()));
} else if (!isa<StoreInst>(K))
K->mutateType(getVecTypeForPair(L->getType(), H->getType()));
unsigned KnownIDs[] = {LLVMContext::MD_tbaa, LLVMContext::MD_alias_scope,
LLVMContext::MD_noalias, LLVMContext::MD_fpmath,
LLVMContext::MD_invariant_group};
combineMetadata(K, H, KnownIDs);
K->andIRFlags(H);
for (unsigned o = 0; o < NumOperands; ++o)
K->setOperand(o, ReplacedOperands[o]);
K->insertAfter(J);
// Instruction insertion point:
Instruction *InsertionPt = K;
Instruction *K1 = nullptr, *K2 = nullptr;
replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2);
// The use dag of the first original instruction must be moved to after
// the location of the second instruction. The entire use dag of the
// first instruction is disjoint from the input dag of the second
// (by definition), and so commutes with it.
moveUsesOfIAfterJ(BB, LoadMoveSetPairs, InsertionPt, I, J);
if (!isa<StoreInst>(I)) {
L->replaceAllUsesWith(K1);
H->replaceAllUsesWith(K2);
}
// Instructions that may read from memory may be in the load move set.
// Once an instruction is fused, we no longer need its move set, and so
// the values of the map never need to be updated. However, when a load
// is fused, we need to merge the entries from both instructions in the
// pair in case those instructions were in the move set of some other
// yet-to-be-fused pair. The loads in question are the keys of the map.
if (I->mayReadFromMemory()) {
std::vector<ValuePair> NewSetMembers;
DenseMap<Value *, std::vector<Value *> >::iterator II =
LoadMoveSet.find(I);
if (II != LoadMoveSet.end())
for (std::vector<Value *>::iterator N = II->second.begin(),
NE = II->second.end(); N != NE; ++N)
NewSetMembers.push_back(ValuePair(K, *N));
DenseMap<Value *, std::vector<Value *> >::iterator JJ =
LoadMoveSet.find(J);
if (JJ != LoadMoveSet.end())
for (std::vector<Value *>::iterator N = JJ->second.begin(),
NE = JJ->second.end(); N != NE; ++N)
NewSetMembers.push_back(ValuePair(K, *N));
for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(),
AE = NewSetMembers.end(); A != AE; ++A) {
LoadMoveSet[A->first].push_back(A->second);
LoadMoveSetPairs.insert(*A);
}
}
// Before removing I, set the iterator to the next instruction.
PI = std::next(BasicBlock::iterator(I));
if (cast<Instruction>(PI) == J)
++PI;
SE->forgetValue(I);
SE->forgetValue(J);
I->eraseFromParent();
J->eraseFromParent();
DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" <<
BB << "\n");
}
DEBUG(dbgs() << "BBV: final: \n" << BB << "\n");
}
}
char BBVectorize::ID = 0;
static const char bb_vectorize_name[] = "Basic-Block Vectorization";
INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
INITIALIZE_PASS_DEPENDENCY(SCEVAAWrapperPass)
INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) {
return new BBVectorize(C);
}
bool
llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) {
BBVectorize BBVectorizer(P, *BB.getParent(), C);
return BBVectorizer.vectorizeBB(BB);
}
//===----------------------------------------------------------------------===//
VectorizeConfig::VectorizeConfig() {
VectorBits = ::VectorBits;
VectorizeBools = !::NoBools;
VectorizeInts = !::NoInts;
VectorizeFloats = !::NoFloats;
VectorizePointers = !::NoPointers;
VectorizeCasts = !::NoCasts;
VectorizeMath = !::NoMath;
VectorizeBitManipulations = !::NoBitManipulation;
VectorizeFMA = !::NoFMA;
VectorizeSelect = !::NoSelect;
VectorizeCmp = !::NoCmp;
VectorizeGEP = !::NoGEP;
VectorizeMemOps = !::NoMemOps;
AlignedOnly = ::AlignedOnly;
ReqChainDepth= ::ReqChainDepth;
SearchLimit = ::SearchLimit;
MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck;
SplatBreaksChain = ::SplatBreaksChain;
MaxInsts = ::MaxInsts;
MaxPairs = ::MaxPairs;
MaxIter = ::MaxIter;
Pow2LenOnly = ::Pow2LenOnly;
NoMemOpBoost = ::NoMemOpBoost;
FastDep = ::FastDep;
}
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