mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-30 21:29:28 +00:00
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152035 91177308-0d34-0410-b5e6-96231b3b80d8
1842 lines
75 KiB
C++
1842 lines
75 KiB
C++
//===- 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"
|
|
#define DEBUG_TYPE BBV_NAME
|
|
#include "llvm/Constants.h"
|
|
#include "llvm/DerivedTypes.h"
|
|
#include "llvm/Function.h"
|
|
#include "llvm/Instructions.h"
|
|
#include "llvm/IntrinsicInst.h"
|
|
#include "llvm/Intrinsics.h"
|
|
#include "llvm/LLVMContext.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/Type.h"
|
|
#include "llvm/ADT/DenseMap.h"
|
|
#include "llvm/ADT/DenseSet.h"
|
|
#include "llvm/ADT/SmallVector.h"
|
|
#include "llvm/ADT/Statistic.h"
|
|
#include "llvm/ADT/STLExtras.h"
|
|
#include "llvm/ADT/StringExtras.h"
|
|
#include "llvm/Analysis/AliasAnalysis.h"
|
|
#include "llvm/Analysis/AliasSetTracker.h"
|
|
#include "llvm/Analysis/ScalarEvolution.h"
|
|
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
|
|
#include "llvm/Analysis/ValueTracking.h"
|
|
#include "llvm/Support/CommandLine.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
#include "llvm/Support/ValueHandle.h"
|
|
#include "llvm/Target/TargetData.h"
|
|
#include "llvm/Transforms/Vectorize.h"
|
|
#include <algorithm>
|
|
#include <map>
|
|
using namespace llvm;
|
|
|
|
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<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<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>
|
|
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>
|
|
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"));
|
|
|
|
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>
|
|
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>
|
|
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"));
|
|
#endif
|
|
|
|
STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize");
|
|
|
|
namespace {
|
|
struct BBVectorize : public BasicBlockPass {
|
|
static char ID; // Pass identification, replacement for typeid
|
|
BBVectorize() : BasicBlockPass(ID) {
|
|
initializeBBVectorizePass(*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
typedef std::pair<Value *, Value *> ValuePair;
|
|
typedef std::pair<ValuePair, size_t> ValuePairWithDepth;
|
|
typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair
|
|
typedef std::pair<std::multimap<Value *, Value *>::iterator,
|
|
std::multimap<Value *, Value *>::iterator> VPIteratorPair;
|
|
typedef std::pair<std::multimap<ValuePair, ValuePair>::iterator,
|
|
std::multimap<ValuePair, ValuePair>::iterator>
|
|
VPPIteratorPair;
|
|
|
|
AliasAnalysis *AA;
|
|
ScalarEvolution *SE;
|
|
TargetData *TD;
|
|
|
|
// FIXME: const correct?
|
|
|
|
bool vectorizePairs(BasicBlock &BB);
|
|
|
|
bool getCandidatePairs(BasicBlock &BB,
|
|
BasicBlock::iterator &Start,
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts);
|
|
|
|
void computeConnectedPairs(std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs);
|
|
|
|
void buildDepMap(BasicBlock &BB,
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
DenseSet<ValuePair> &PairableInstUsers);
|
|
|
|
void choosePairs(std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
DenseSet<ValuePair> &PairableInstUsers,
|
|
DenseMap<Value *, Value *>& ChosenPairs);
|
|
|
|
void fuseChosenPairs(BasicBlock &BB,
|
|
std::vector<Value *> &PairableInsts,
|
|
DenseMap<Value *, Value *>& ChosenPairs);
|
|
|
|
bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore);
|
|
|
|
bool areInstsCompatible(Instruction *I, Instruction *J,
|
|
bool IsSimpleLoadStore);
|
|
|
|
bool trackUsesOfI(DenseSet<Value *> &Users,
|
|
AliasSetTracker &WriteSet, Instruction *I,
|
|
Instruction *J, bool UpdateUsers = true,
|
|
std::multimap<Value *, Value *> *LoadMoveSet = 0);
|
|
|
|
void computePairsConnectedTo(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
ValuePair P);
|
|
|
|
bool pairsConflict(ValuePair P, ValuePair Q,
|
|
DenseSet<ValuePair> &PairableInstUsers,
|
|
std::multimap<ValuePair, ValuePair> *PairableInstUserMap = 0);
|
|
|
|
bool pairWillFormCycle(ValuePair P,
|
|
std::multimap<ValuePair, ValuePair> &PairableInstUsers,
|
|
DenseSet<ValuePair> &CurrentPairs);
|
|
|
|
void pruneTreeFor(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
DenseSet<ValuePair> &PairableInstUsers,
|
|
std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
|
|
DenseMap<Value *, Value *> &ChosenPairs,
|
|
DenseMap<ValuePair, size_t> &Tree,
|
|
DenseSet<ValuePair> &PrunedTree, ValuePair J,
|
|
bool UseCycleCheck);
|
|
|
|
void buildInitialTreeFor(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
DenseSet<ValuePair> &PairableInstUsers,
|
|
DenseMap<Value *, Value *> &ChosenPairs,
|
|
DenseMap<ValuePair, size_t> &Tree, ValuePair J);
|
|
|
|
void findBestTreeFor(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
DenseSet<ValuePair> &PairableInstUsers,
|
|
std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
|
|
DenseMap<Value *, Value *> &ChosenPairs,
|
|
DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
|
|
size_t &BestEffSize, VPIteratorPair ChoiceRange,
|
|
bool UseCycleCheck);
|
|
|
|
Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I,
|
|
Instruction *J, unsigned o, bool &FlipMemInputs);
|
|
|
|
void fillNewShuffleMask(LLVMContext& Context, Instruction *J,
|
|
unsigned NumElem, unsigned MaskOffset, unsigned NumInElem,
|
|
unsigned IdxOffset, std::vector<Constant*> &Mask);
|
|
|
|
Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I,
|
|
Instruction *J);
|
|
|
|
Value *getReplacementInput(LLVMContext& Context, Instruction *I,
|
|
Instruction *J, unsigned o, bool FlipMemInputs);
|
|
|
|
void getReplacementInputsForPair(LLVMContext& Context, Instruction *I,
|
|
Instruction *J, SmallVector<Value *, 3> &ReplacedOperands,
|
|
bool &FlipMemInputs);
|
|
|
|
void replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
|
|
Instruction *J, Instruction *K,
|
|
Instruction *&InsertionPt, Instruction *&K1,
|
|
Instruction *&K2, bool &FlipMemInputs);
|
|
|
|
void collectPairLoadMoveSet(BasicBlock &BB,
|
|
DenseMap<Value *, Value *> &ChosenPairs,
|
|
std::multimap<Value *, Value *> &LoadMoveSet,
|
|
Instruction *I);
|
|
|
|
void collectLoadMoveSet(BasicBlock &BB,
|
|
std::vector<Value *> &PairableInsts,
|
|
DenseMap<Value *, Value *> &ChosenPairs,
|
|
std::multimap<Value *, Value *> &LoadMoveSet);
|
|
|
|
bool canMoveUsesOfIAfterJ(BasicBlock &BB,
|
|
std::multimap<Value *, Value *> &LoadMoveSet,
|
|
Instruction *I, Instruction *J);
|
|
|
|
void moveUsesOfIAfterJ(BasicBlock &BB,
|
|
std::multimap<Value *, Value *> &LoadMoveSet,
|
|
Instruction *&InsertionPt,
|
|
Instruction *I, Instruction *J);
|
|
|
|
virtual bool runOnBasicBlock(BasicBlock &BB) {
|
|
AA = &getAnalysis<AliasAnalysis>();
|
|
SE = &getAnalysis<ScalarEvolution>();
|
|
TD = getAnalysisIfAvailable<TargetData>();
|
|
|
|
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.
|
|
for (unsigned v = 2, n = 1; v <= VectorBits && (!MaxIter || n <= 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;
|
|
}
|
|
|
|
DEBUG(dbgs() << "BBV: done!\n");
|
|
return changed;
|
|
}
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
BasicBlockPass::getAnalysisUsage(AU);
|
|
AU.addRequired<AliasAnalysis>();
|
|
AU.addRequired<ScalarEvolution>();
|
|
AU.addPreserved<AliasAnalysis>();
|
|
AU.addPreserved<ScalarEvolution>();
|
|
AU.setPreservesCFG();
|
|
}
|
|
|
|
// This returns the vector type that holds a pair of the provided type.
|
|
// If the provided type is already a vector, then its length is doubled.
|
|
static inline VectorType *getVecTypeForPair(Type *ElemTy) {
|
|
if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) {
|
|
unsigned numElem = VTy->getNumElements();
|
|
return VectorType::get(ElemTy->getScalarType(), numElem*2);
|
|
}
|
|
|
|
return VectorType::get(ElemTy, 2);
|
|
}
|
|
|
|
// 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.
|
|
static 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 trees 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 (!NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V)))
|
|
return ReqChainDepth/2;
|
|
|
|
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. This function assumes that both instructions
|
|
// have the same type.
|
|
bool getPairPtrInfo(Instruction *I, Instruction *J,
|
|
Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment,
|
|
int64_t &OffsetInElmts) {
|
|
OffsetInElmts = 0;
|
|
if (isa<LoadInst>(I)) {
|
|
IPtr = cast<LoadInst>(I)->getPointerOperand();
|
|
JPtr = cast<LoadInst>(J)->getPointerOperand();
|
|
IAlignment = cast<LoadInst>(I)->getAlignment();
|
|
JAlignment = cast<LoadInst>(J)->getAlignment();
|
|
} else {
|
|
IPtr = cast<StoreInst>(I)->getPointerOperand();
|
|
JPtr = cast<StoreInst>(J)->getPointerOperand();
|
|
IAlignment = cast<StoreInst>(I)->getAlignment();
|
|
JAlignment = cast<StoreInst>(J)->getAlignment();
|
|
}
|
|
|
|
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();
|
|
|
|
Type *VTy = cast<PointerType>(IPtr->getType())->getElementType();
|
|
int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy);
|
|
|
|
assert(VTy == cast<PointerType>(JPtr->getType())->getElementType());
|
|
|
|
OffsetInElmts = Offset/VTyTSS;
|
|
return (abs64(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;
|
|
|
|
unsigned 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:
|
|
return !NoMath;
|
|
case Intrinsic::fma:
|
|
return !NoFMA;
|
|
}
|
|
}
|
|
|
|
// Returns true if J is the second element in some pair referenced by
|
|
// some multimap pair iterator pair.
|
|
template <typename V>
|
|
bool isSecondInIteratorPair(V J, std::pair<
|
|
typename std::multimap<V, V>::iterator,
|
|
typename std::multimap<V, V>::iterator> PairRange) {
|
|
for (typename std::multimap<V, V>::iterator K = PairRange.first;
|
|
K != PairRange.second; ++K)
|
|
if (K->second == J) return true;
|
|
|
|
return false;
|
|
}
|
|
};
|
|
|
|
// 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 ShouldContinue;
|
|
BasicBlock::iterator Start = BB.getFirstInsertionPt();
|
|
|
|
std::vector<Value *> AllPairableInsts;
|
|
DenseMap<Value *, Value *> AllChosenPairs;
|
|
|
|
do {
|
|
std::vector<Value *> PairableInsts;
|
|
std::multimap<Value *, Value *> CandidatePairs;
|
|
ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs,
|
|
PairableInsts);
|
|
if (PairableInsts.empty()) continue;
|
|
|
|
// 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).
|
|
|
|
std::multimap<ValuePair, ValuePair> ConnectedPairs;
|
|
computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs);
|
|
if (ConnectedPairs.empty()) continue;
|
|
|
|
// 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 tree meeting the depth requirement on at
|
|
// least one branch. Then select all pairings that are part of that tree
|
|
// and remove them from the list of available pairings and pairable
|
|
// variables.
|
|
|
|
DenseMap<Value *, Value *> ChosenPairs;
|
|
choosePairs(CandidatePairs, PairableInsts, ConnectedPairs,
|
|
PairableInstUsers, ChosenPairs);
|
|
|
|
if (ChosenPairs.empty()) continue;
|
|
AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(),
|
|
PairableInsts.end());
|
|
AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end());
|
|
} 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);
|
|
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 || NoMemOps)
|
|
return false;
|
|
} else if (StoreInst *S = dyn_cast<StoreInst>(I)) {
|
|
// Vectorize simple stores if possbile:
|
|
IsSimpleLoadStore = S->isSimple();
|
|
if (!IsSimpleLoadStore || NoMemOps)
|
|
return false;
|
|
} else if (CastInst *C = dyn_cast<CastInst>(I)) {
|
|
// We can vectorize casts, but not casts of pointer types, etc.
|
|
if (NoCasts)
|
|
return false;
|
|
|
|
Type *SrcTy = C->getSrcTy();
|
|
if (!SrcTy->isSingleValueType() || SrcTy->isPointerTy())
|
|
return false;
|
|
|
|
Type *DestTy = C->getDestTy();
|
|
if (!DestTy->isSingleValueType() || DestTy->isPointerTy())
|
|
return false;
|
|
} else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) ||
|
|
isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) {
|
|
return false;
|
|
}
|
|
|
|
// We can't vectorize memory operations without target data
|
|
if (TD == 0 && IsSimpleLoadStore)
|
|
return false;
|
|
|
|
Type *T1, *T2;
|
|
if (isa<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 = cast<StoreInst>(I)->getValueOperand();
|
|
T1 = IVal->getType();
|
|
} else {
|
|
T1 = I->getType();
|
|
}
|
|
|
|
if (I->isCast())
|
|
T2 = cast<CastInst>(I)->getSrcTy();
|
|
else
|
|
T2 = T1;
|
|
|
|
// Not every type can be vectorized...
|
|
if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) ||
|
|
!(VectorType::isValidElementType(T2) || T2->isVectorTy()))
|
|
return false;
|
|
|
|
if (NoInts && (T1->isIntOrIntVectorTy() || T2->isIntOrIntVectorTy()))
|
|
return false;
|
|
|
|
if (NoFloats && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy()))
|
|
return false;
|
|
|
|
if (T1->getPrimitiveSizeInBits() > VectorBits/2 ||
|
|
T2->getPrimitiveSizeInBits() > VectorBits/2)
|
|
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 tree of I.
|
|
bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J,
|
|
bool IsSimpleLoadStore) {
|
|
DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I <<
|
|
" <-> " << *J << "\n");
|
|
|
|
// Loads and stores can be merged if they have different alignments,
|
|
// but are otherwise the same.
|
|
LoadInst *LI, *LJ;
|
|
StoreInst *SI, *SJ;
|
|
if ((LI = dyn_cast<LoadInst>(I)) && (LJ = dyn_cast<LoadInst>(J))) {
|
|
if (I->getType() != J->getType())
|
|
return false;
|
|
|
|
if (LI->getPointerOperand()->getType() !=
|
|
LJ->getPointerOperand()->getType() ||
|
|
LI->isVolatile() != LJ->isVolatile() ||
|
|
LI->getOrdering() != LJ->getOrdering() ||
|
|
LI->getSynchScope() != LJ->getSynchScope())
|
|
return false;
|
|
} else if ((SI = dyn_cast<StoreInst>(I)) && (SJ = dyn_cast<StoreInst>(J))) {
|
|
if (SI->getValueOperand()->getType() !=
|
|
SJ->getValueOperand()->getType() ||
|
|
SI->getPointerOperand()->getType() !=
|
|
SJ->getPointerOperand()->getType() ||
|
|
SI->isVolatile() != SJ->isVolatile() ||
|
|
SI->getOrdering() != SJ->getOrdering() ||
|
|
SI->getSynchScope() != SJ->getSynchScope())
|
|
return false;
|
|
} else if (!J->isSameOperationAs(I)) {
|
|
return false;
|
|
}
|
|
// FIXME: handle addsub-type operations!
|
|
|
|
if (IsSimpleLoadStore) {
|
|
Value *IPtr, *JPtr;
|
|
unsigned IAlignment, JAlignment;
|
|
int64_t OffsetInElmts = 0;
|
|
if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
|
|
OffsetInElmts) && abs64(OffsetInElmts) == 1) {
|
|
if (AlignedOnly) {
|
|
Type *aType = isa<StoreInst>(I) ?
|
|
cast<StoreInst>(I)->getValueOperand()->getType() : I->getType();
|
|
// An aligned load or store is possible only if the instruction
|
|
// with the lower offset has an alignment suitable for the
|
|
// vector type.
|
|
|
|
unsigned BottomAlignment = IAlignment;
|
|
if (OffsetInElmts < 0) BottomAlignment = JAlignment;
|
|
|
|
Type *VType = getVecTypeForPair(aType);
|
|
unsigned VecAlignment = TD->getPrefTypeAlignment(VType);
|
|
if (BottomAlignment < VecAlignment)
|
|
return false;
|
|
}
|
|
} else {
|
|
return false;
|
|
}
|
|
} else if (isa<ShuffleVectorInst>(I)) {
|
|
// Only merge two shuffles if they're both constant
|
|
return isa<Constant>(I->getOperand(2)) &&
|
|
isa<Constant>(J->getOperand(2));
|
|
// FIXME: We may want to vectorize non-constant shuffles also.
|
|
}
|
|
|
|
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 multimap
|
|
// 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,
|
|
std::multimap<Value *, Value *> *LoadMoveSet) {
|
|
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 (LoadMoveSet) {
|
|
VPIteratorPair JPairRange = LoadMoveSet->equal_range(J);
|
|
UsesI = isSecondInIteratorPair<Value*>(I, JPairRange);
|
|
} 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,
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts) {
|
|
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);
|
|
bool JAfterStart = IAfterStart;
|
|
BasicBlock::iterator J = llvm::next(I);
|
|
for (unsigned ss = 0; J != E && ss <= 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, !FastDep);
|
|
if (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.
|
|
if (!areInstsCompatible(I, J, IsSimpleLoadStore)) continue;
|
|
|
|
// J is a candidate for merging with I.
|
|
if (!PairableInsts.size() ||
|
|
PairableInsts[PairableInsts.size()-1] != I) {
|
|
PairableInsts.push_back(I);
|
|
}
|
|
|
|
CandidatePairs.insert(ValuePair(I, J));
|
|
|
|
// The next call to this function must start after the last instruction
|
|
// selected during this invocation.
|
|
if (JAfterStart) {
|
|
Start = llvm::next(J);
|
|
IAfterStart = JAfterStart = false;
|
|
}
|
|
|
|
DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair "
|
|
<< *I << " <-> " << *J << "\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() >= MaxInsts) {
|
|
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(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
ValuePair P) {
|
|
// For each possible pairing for this variable, look at the uses of
|
|
// the first value...
|
|
for (Value::use_iterator I = P.first->use_begin(),
|
|
E = P.first->use_end(); I != E; ++I) {
|
|
VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
|
|
|
|
// For each use of the first variable, look for uses of the second
|
|
// variable...
|
|
for (Value::use_iterator J = P.second->use_begin(),
|
|
E2 = P.second->use_end(); J != E2; ++J) {
|
|
VPIteratorPair JPairRange = CandidatePairs.equal_range(*J);
|
|
|
|
// Look for <I, J>:
|
|
if (isSecondInIteratorPair<Value*>(*J, IPairRange))
|
|
ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J)));
|
|
|
|
// Look for <J, I>:
|
|
if (isSecondInIteratorPair<Value*>(*I, JPairRange))
|
|
ConnectedPairs.insert(VPPair(P, ValuePair(*J, *I)));
|
|
}
|
|
|
|
if (SplatBreaksChain) continue;
|
|
// Look for cases where just the first value in the pair is used by
|
|
// both members of another pair (splatting).
|
|
for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) {
|
|
if (isSecondInIteratorPair<Value*>(*J, IPairRange))
|
|
ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J)));
|
|
}
|
|
}
|
|
|
|
if (SplatBreaksChain) return;
|
|
// Look for cases where just the second value in the pair is used by
|
|
// both members of another pair (splatting).
|
|
for (Value::use_iterator I = P.second->use_begin(),
|
|
E = P.second->use_end(); I != E; ++I) {
|
|
VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
|
|
|
|
for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) {
|
|
if (isSecondInIteratorPair<Value*>(*J, IPairRange))
|
|
ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J)));
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs) {
|
|
|
|
for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
|
|
PE = PairableInsts.end(); PI != PE; ++PI) {
|
|
VPIteratorPair choiceRange = CandidatePairs.equal_range(*PI);
|
|
|
|
for (std::multimap<Value *, Value *>::iterator P = choiceRange.first;
|
|
P != choiceRange.second; ++P)
|
|
computePairsConnectedTo(CandidatePairs, PairableInsts,
|
|
ConnectedPairs, *P);
|
|
}
|
|
|
|
DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size()
|
|
<< " 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 tree of A. If B is in the use tree of A, then B
|
|
// depends on the output of A.
|
|
void BBVectorize::buildDepMap(
|
|
BasicBlock &BB,
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
DenseSet<ValuePair> &PairableInstUsers) {
|
|
DenseSet<Value *> IsInPair;
|
|
for (std::multimap<Value *, Value *>::iterator C = CandidatePairs.begin(),
|
|
E = CandidatePairs.end(); C != E; ++C) {
|
|
IsInPair.insert(C->first);
|
|
IsInPair.insert(C->second);
|
|
}
|
|
|
|
// Iterate through the basic block, recording all Users of each
|
|
// pairable instruction.
|
|
|
|
BasicBlock::iterator E = BB.end();
|
|
for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) {
|
|
if (IsInPair.find(I) == IsInPair.end()) continue;
|
|
|
|
DenseSet<Value *> Users;
|
|
AliasSetTracker WriteSet(*AA);
|
|
for (BasicBlock::iterator J = llvm::next(I); J != E; ++J)
|
|
(void) trackUsesOfI(Users, WriteSet, I, J);
|
|
|
|
for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end();
|
|
U != E; ++U)
|
|
PairableInstUsers.insert(ValuePair(I, *U));
|
|
}
|
|
}
|
|
|
|
// 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,
|
|
std::multimap<ValuePair, ValuePair> *PairableInstUserMap) {
|
|
// 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 (same is true of
|
|
// most uses of std::multimap).
|
|
if (PUsesQ) {
|
|
VPPIteratorPair QPairRange = PairableInstUserMap->equal_range(Q);
|
|
if (!isSecondInIteratorPair(P, QPairRange))
|
|
PairableInstUserMap->insert(VPPair(Q, P));
|
|
}
|
|
if (QUsesP) {
|
|
VPPIteratorPair PPairRange = PairableInstUserMap->equal_range(P);
|
|
if (!isSecondInIteratorPair(Q, PPairRange))
|
|
PairableInstUserMap->insert(VPPair(P, 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,
|
|
std::multimap<ValuePair, 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");
|
|
VPPIteratorPair QPairRange = PairableInstUserMap.equal_range(QTop);
|
|
for (std::multimap<ValuePair, ValuePair>::iterator C = QPairRange.first;
|
|
C != QPairRange.second; ++C) {
|
|
if (C->second == P) {
|
|
DEBUG(dbgs()
|
|
<< "BBV: rejected to prevent non-trivial cycle formation: "
|
|
<< *C->first.first << " <-> " << *C->first.second << "\n");
|
|
return true;
|
|
}
|
|
|
|
if (CurrentPairs.count(C->second) && !Visited.count(C->second))
|
|
Q.push_back(C->second);
|
|
}
|
|
} while (!Q.empty());
|
|
|
|
return false;
|
|
}
|
|
|
|
// This function builds the initial tree of connected pairs with the
|
|
// pair J at the root.
|
|
void BBVectorize::buildInitialTreeFor(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
DenseSet<ValuePair> &PairableInstUsers,
|
|
DenseMap<Value *, Value *> &ChosenPairs,
|
|
DenseMap<ValuePair, size_t> &Tree, ValuePair J) {
|
|
// Each of these pairs is viewed as the root node of a Tree. The Tree
|
|
// is then walked (depth-first). As this happens, we keep track of
|
|
// the pairs that compose the Tree and the maximum depth of the Tree.
|
|
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;
|
|
VPPIteratorPair qtRange = ConnectedPairs.equal_range(QTop.first);
|
|
for (std::multimap<ValuePair, ValuePair>::iterator k = qtRange.first;
|
|
k != qtRange.second; ++k) {
|
|
// Make sure that this child pair is still a candidate:
|
|
bool IsStillCand = false;
|
|
VPIteratorPair checkRange =
|
|
CandidatePairs.equal_range(k->second.first);
|
|
for (std::multimap<Value *, Value *>::iterator m = checkRange.first;
|
|
m != checkRange.second; ++m) {
|
|
if (m->second == k->second.second) {
|
|
IsStillCand = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (IsStillCand) {
|
|
DenseMap<ValuePair, size_t>::iterator C = Tree.find(k->second);
|
|
if (C == Tree.end()) {
|
|
size_t d = getDepthFactor(k->second.first);
|
|
Q.push_back(ValuePairWithDepth(k->second, QTop.second+d));
|
|
MoreChildren = true;
|
|
} else {
|
|
MaxChildDepth = std::max(MaxChildDepth, C->second);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!MoreChildren) {
|
|
// Record the current pair as part of the Tree:
|
|
Tree.insert(ValuePairWithDepth(QTop.first, MaxChildDepth));
|
|
Q.pop_back();
|
|
}
|
|
} while (!Q.empty());
|
|
}
|
|
|
|
// Given some initial tree, prune it by removing conflicting pairs (pairs
|
|
// that cannot be simultaneously chosen for vectorization).
|
|
void BBVectorize::pruneTreeFor(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
DenseSet<ValuePair> &PairableInstUsers,
|
|
std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
|
|
DenseMap<Value *, Value *> &ChosenPairs,
|
|
DenseMap<ValuePair, size_t> &Tree,
|
|
DenseSet<ValuePair> &PrunedTree, 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();
|
|
PrunedTree.insert(QTop.first);
|
|
|
|
// Visit each child, pruning as necessary...
|
|
DenseMap<ValuePair, size_t> BestChildren;
|
|
VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first);
|
|
for (std::multimap<ValuePair, ValuePair>::iterator K = QTopRange.first;
|
|
K != QTopRange.second; ++K) {
|
|
DenseMap<ValuePair, size_t>::iterator C = Tree.find(K->second);
|
|
if (C == Tree.end()) continue;
|
|
|
|
// This child is in the Tree, 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 Tree 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 (DenseMap<ValuePair, size_t>::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 : 0)) {
|
|
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 Tree. If that is the case, ignore this child.
|
|
for (DenseSet<ValuePair>::iterator T = PrunedTree.begin(),
|
|
E2 = PrunedTree.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 : 0)) {
|
|
CanAdd = false;
|
|
break;
|
|
}
|
|
|
|
CurrentPairs.insert(*T);
|
|
}
|
|
if (!CanAdd) continue;
|
|
|
|
// And check the queue too...
|
|
for (SmallVector<ValuePairWithDepth, 32>::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 : 0)) {
|
|
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 : 0)) {
|
|
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 tree 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 (DenseMap<ValuePair, size_t>::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))
|
|
BestChildren.erase(C2++);
|
|
else
|
|
++C2;
|
|
}
|
|
|
|
BestChildren.insert(ValuePairWithDepth(C->first, C->second));
|
|
}
|
|
|
|
for (DenseMap<ValuePair, size_t>::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 tree of mututally-compatible connected
|
|
// pairs, given the choice of root pairs as an iterator range.
|
|
void BBVectorize::findBestTreeFor(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
DenseSet<ValuePair> &PairableInstUsers,
|
|
std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
|
|
DenseMap<Value *, Value *> &ChosenPairs,
|
|
DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
|
|
size_t &BestEffSize, VPIteratorPair ChoiceRange,
|
|
bool UseCycleCheck) {
|
|
for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first;
|
|
J != ChoiceRange.second; ++J) {
|
|
|
|
// Before going any further, make sure that this pair does not
|
|
// conflict with any already-selected pairs (see comment below
|
|
// near the Tree 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, *J, PairableInstUsers,
|
|
UseCycleCheck ? &PairableInstUserMap : 0)) {
|
|
DoesConflict = true;
|
|
break;
|
|
}
|
|
|
|
ChosenPairSet.insert(*C);
|
|
}
|
|
if (DoesConflict) continue;
|
|
|
|
if (UseCycleCheck &&
|
|
pairWillFormCycle(*J, PairableInstUserMap, ChosenPairSet))
|
|
continue;
|
|
|
|
DenseMap<ValuePair, size_t> Tree;
|
|
buildInitialTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
|
|
PairableInstUsers, ChosenPairs, Tree, *J);
|
|
|
|
// Because we'll keep the child with the largest depth, the largest
|
|
// depth is still the same in the unpruned Tree.
|
|
size_t MaxDepth = Tree.lookup(*J);
|
|
|
|
DEBUG(if (DebugPairSelection) dbgs() << "BBV: found Tree for pair {"
|
|
<< *J->first << " <-> " << *J->second << "} of depth " <<
|
|
MaxDepth << " and size " << Tree.size() << "\n");
|
|
|
|
// At this point the Tree has been constructed, but, may contain
|
|
// contradictory children (meaning that different children of
|
|
// some tree node may be attempting to fuse the same instruction).
|
|
// So now we walk the tree 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> PrunedTree;
|
|
pruneTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
|
|
PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree,
|
|
PrunedTree, *J, UseCycleCheck);
|
|
|
|
size_t EffSize = 0;
|
|
for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
|
|
E = PrunedTree.end(); S != E; ++S)
|
|
EffSize += getDepthFactor(S->first);
|
|
|
|
DEBUG(if (DebugPairSelection)
|
|
dbgs() << "BBV: found pruned Tree for pair {"
|
|
<< *J->first << " <-> " << *J->second << "} of depth " <<
|
|
MaxDepth << " and size " << PrunedTree.size() <<
|
|
" (effective size: " << EffSize << ")\n");
|
|
if (MaxDepth >= ReqChainDepth && EffSize > BestEffSize) {
|
|
BestMaxDepth = MaxDepth;
|
|
BestEffSize = EffSize;
|
|
BestTree = PrunedTree;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Given the list of candidate pairs, this function selects those
|
|
// that will be fused into vector instructions.
|
|
void BBVectorize::choosePairs(
|
|
std::multimap<Value *, Value *> &CandidatePairs,
|
|
std::vector<Value *> &PairableInsts,
|
|
std::multimap<ValuePair, ValuePair> &ConnectedPairs,
|
|
DenseSet<ValuePair> &PairableInstUsers,
|
|
DenseMap<Value *, Value *>& ChosenPairs) {
|
|
bool UseCycleCheck = CandidatePairs.size() <= MaxCandPairsForCycleCheck;
|
|
std::multimap<ValuePair, ValuePair> PairableInstUserMap;
|
|
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.count(*I);
|
|
if (!NumChoices) continue;
|
|
|
|
VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I);
|
|
|
|
// The best pair to choose and its tree:
|
|
size_t BestMaxDepth = 0, BestEffSize = 0;
|
|
DenseSet<ValuePair> BestTree;
|
|
findBestTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
|
|
PairableInstUsers, PairableInstUserMap, ChosenPairs,
|
|
BestTree, BestMaxDepth, BestEffSize, ChoiceRange,
|
|
UseCycleCheck);
|
|
|
|
// A tree has been chosen (or not) at this point. If no tree was
|
|
// chosen, then this instruction, I, cannot be paired (and is no longer
|
|
// considered).
|
|
|
|
DEBUG(if (BestTree.size() > 0)
|
|
dbgs() << "BBV: selected pairs in the best tree for: "
|
|
<< *cast<Instruction>(*I) << "\n");
|
|
|
|
for (DenseSet<ValuePair>::iterator S = BestTree.begin(),
|
|
SE2 = BestTree.end(); S != SE2; ++S) {
|
|
// Insert the members of this tree 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 tree.
|
|
for (std::multimap<Value *, Value *>::iterator K =
|
|
CandidatePairs.begin(); K != CandidatePairs.end();) {
|
|
if (K->first == S->first || K->second == S->first ||
|
|
K->second == S->second || K->first == S->second) {
|
|
// Don't remove the actual pair chosen so that it can be used
|
|
// in subsequent tree selections.
|
|
if (!(K->first == S->first && K->second == S->second))
|
|
CandidatePairs.erase(K++);
|
|
else
|
|
++K;
|
|
} else {
|
|
++K;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
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,
|
|
bool &FlipMemInputs) {
|
|
Value *IPtr, *JPtr;
|
|
unsigned IAlignment, JAlignment;
|
|
int64_t OffsetInElmts;
|
|
(void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
|
|
OffsetInElmts);
|
|
|
|
// The pointer value is taken to be the one with the lowest offset.
|
|
Value *VPtr;
|
|
if (OffsetInElmts > 0) {
|
|
VPtr = IPtr;
|
|
} else {
|
|
FlipMemInputs = true;
|
|
VPtr = JPtr;
|
|
}
|
|
|
|
Type *ArgType = cast<PointerType>(IPtr->getType())->getElementType();
|
|
Type *VArgType = getVecTypeForPair(ArgType);
|
|
Type *VArgPtrType = PointerType::get(VArgType,
|
|
cast<PointerType>(IPtr->getType())->getAddressSpace());
|
|
return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o),
|
|
/* insert before */ FlipMemInputs ? J : I);
|
|
}
|
|
|
|
void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J,
|
|
unsigned NumElem, unsigned MaskOffset, unsigned NumInElem,
|
|
unsigned IdxOffset, std::vector<Constant*> &Mask) {
|
|
for (unsigned v = 0; v < NumElem/2; ++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) NumInElem)
|
|
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 *ArgType = I->getType();
|
|
Type *VArgType = getVecTypeForPair(ArgType);
|
|
|
|
// 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 = cast<VectorType>(VArgType)->getNumElements();
|
|
std::vector<Constant*> Mask(NumElem);
|
|
|
|
Type *OpType = I->getOperand(0)->getType();
|
|
unsigned NumInElem = cast<VectorType>(OpType)->getNumElements();
|
|
|
|
// For the mask from the first pair...
|
|
fillNewShuffleMask(Context, I, NumElem, 0, NumInElem, 0, Mask);
|
|
|
|
// For the mask from the second pair...
|
|
fillNewShuffleMask(Context, J, NumElem, NumElem/2, NumInElem, NumInElem,
|
|
Mask);
|
|
|
|
return ConstantVector::get(Mask);
|
|
}
|
|
|
|
// 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 FlipMemInputs) {
|
|
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 *ArgType = I->getOperand(o)->getType();
|
|
VectorType *VArgType = getVecTypeForPair(ArgType);
|
|
|
|
Instruction *L = I, *H = J;
|
|
if (FlipMemInputs) {
|
|
L = J;
|
|
H = I;
|
|
}
|
|
|
|
if (ArgType->isVectorTy()) {
|
|
unsigned numElem = cast<VectorType>(VArgType)->getNumElements();
|
|
std::vector<Constant*> Mask(numElem);
|
|
for (unsigned v = 0; v < numElem; ++v)
|
|
Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
|
|
|
|
Instruction *BV = new ShuffleVectorInst(L->getOperand(o),
|
|
H->getOperand(o),
|
|
ConstantVector::get(Mask),
|
|
getReplacementName(I, true, o));
|
|
BV->insertBefore(J);
|
|
return BV;
|
|
}
|
|
|
|
// If these two inputs are the output of another vector instruction,
|
|
// then we should use that output directly. It might be necessary to
|
|
// permute it first. [When pairings are fused recursively, you can
|
|
// end up with cases where a large vector is decomposed into scalars
|
|
// using extractelement instructions, then built into size-2
|
|
// vectors using insertelement and the into larger vectors using
|
|
// shuffles. InstCombine does not simplify all of these cases well,
|
|
// and so we make sure that shuffles are generated here when possible.
|
|
ExtractElementInst *LEE
|
|
= dyn_cast<ExtractElementInst>(L->getOperand(o));
|
|
ExtractElementInst *HEE
|
|
= dyn_cast<ExtractElementInst>(H->getOperand(o));
|
|
|
|
if (LEE && HEE &&
|
|
LEE->getOperand(0)->getType() == HEE->getOperand(0)->getType()) {
|
|
VectorType *EEType = cast<VectorType>(LEE->getOperand(0)->getType());
|
|
unsigned LowIndx = cast<ConstantInt>(LEE->getOperand(1))->getZExtValue();
|
|
unsigned HighIndx = cast<ConstantInt>(HEE->getOperand(1))->getZExtValue();
|
|
if (LEE->getOperand(0) == HEE->getOperand(0)) {
|
|
if (LowIndx == 0 && HighIndx == 1)
|
|
return LEE->getOperand(0);
|
|
|
|
std::vector<Constant*> Mask(2);
|
|
Mask[0] = ConstantInt::get(Type::getInt32Ty(Context), LowIndx);
|
|
Mask[1] = ConstantInt::get(Type::getInt32Ty(Context), HighIndx);
|
|
|
|
Instruction *BV = new ShuffleVectorInst(LEE->getOperand(0),
|
|
UndefValue::get(EEType),
|
|
ConstantVector::get(Mask),
|
|
getReplacementName(I, true, o));
|
|
BV->insertBefore(J);
|
|
return BV;
|
|
}
|
|
|
|
std::vector<Constant*> Mask(2);
|
|
HighIndx += EEType->getNumElements();
|
|
Mask[0] = ConstantInt::get(Type::getInt32Ty(Context), LowIndx);
|
|
Mask[1] = ConstantInt::get(Type::getInt32Ty(Context), HighIndx);
|
|
|
|
Instruction *BV = new ShuffleVectorInst(LEE->getOperand(0),
|
|
HEE->getOperand(0),
|
|
ConstantVector::get(Mask),
|
|
getReplacementName(I, true, o));
|
|
BV->insertBefore(J);
|
|
return BV;
|
|
}
|
|
|
|
Instruction *BV1 = InsertElementInst::Create(
|
|
UndefValue::get(VArgType),
|
|
L->getOperand(o), CV0,
|
|
getReplacementName(I, true, o, 1));
|
|
BV1->insertBefore(I);
|
|
Instruction *BV2 = InsertElementInst::Create(BV1, H->getOperand(o),
|
|
CV1,
|
|
getReplacementName(I, true, o, 2));
|
|
BV2->insertBefore(J);
|
|
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,
|
|
SmallVector<Value *, 3> &ReplacedOperands,
|
|
bool &FlipMemInputs) {
|
|
FlipMemInputs = false;
|
|
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,
|
|
FlipMemInputs);
|
|
continue;
|
|
} else if (isa<CallInst>(I) && o == NumOperands-1) {
|
|
Function *F = cast<CallInst>(I)->getCalledFunction();
|
|
unsigned IID = F->getIntrinsicID();
|
|
BasicBlock &BB = *I->getParent();
|
|
|
|
Module *M = BB.getParent()->getParent();
|
|
Type *ArgType = I->getType();
|
|
Type *VArgType = getVecTypeForPair(ArgType);
|
|
|
|
// FIXME: is it safe to do this here?
|
|
ReplacedOperands[o] = Intrinsic::getDeclaration(M,
|
|
(Intrinsic::ID) IID, VArgType);
|
|
continue;
|
|
} else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) {
|
|
ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J);
|
|
continue;
|
|
}
|
|
|
|
ReplacedOperands[o] =
|
|
getReplacementInput(Context, I, J, o, FlipMemInputs);
|
|
}
|
|
}
|
|
|
|
// 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,
|
|
bool &FlipMemInputs) {
|
|
Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
|
|
Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
|
|
|
|
if (isa<StoreInst>(I)) {
|
|
AA->replaceWithNewValue(I, K);
|
|
AA->replaceWithNewValue(J, K);
|
|
} else {
|
|
Type *IType = I->getType();
|
|
Type *VType = getVecTypeForPair(IType);
|
|
|
|
if (IType->isVectorTy()) {
|
|
unsigned numElem = cast<VectorType>(IType)->getNumElements();
|
|
std::vector<Constant*> Mask1(numElem), Mask2(numElem);
|
|
for (unsigned v = 0; v < numElem; ++v) {
|
|
Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
|
|
Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElem+v);
|
|
}
|
|
|
|
K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
|
|
ConstantVector::get(
|
|
FlipMemInputs ? Mask2 : Mask1),
|
|
getReplacementName(K, false, 1));
|
|
K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
|
|
ConstantVector::get(
|
|
FlipMemInputs ? Mask1 : Mask2),
|
|
getReplacementName(K, false, 2));
|
|
} else {
|
|
K1 = ExtractElementInst::Create(K, FlipMemInputs ? CV1 : CV0,
|
|
getReplacementName(K, false, 1));
|
|
K2 = ExtractElementInst::Create(K, FlipMemInputs ? CV0 : 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,
|
|
std::multimap<Value *, Value *> &LoadMoveSet,
|
|
Instruction *I, Instruction *J) {
|
|
// Skip to the first instruction past I.
|
|
BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I));
|
|
|
|
DenseSet<Value *> Users;
|
|
AliasSetTracker WriteSet(*AA);
|
|
for (; cast<Instruction>(L) != J; ++L)
|
|
(void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet);
|
|
|
|
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, &LoadMoveSet);
|
|
}
|
|
|
|
// Move all uses of the function I (including pairing-induced uses) after J.
|
|
void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB,
|
|
std::multimap<Value *, Value *> &LoadMoveSet,
|
|
Instruction *&InsertionPt,
|
|
Instruction *I, Instruction *J) {
|
|
// Skip to the first instruction past I.
|
|
BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I));
|
|
|
|
DenseSet<Value *> Users;
|
|
AliasSetTracker WriteSet(*AA);
|
|
for (; cast<Instruction>(L) != J;) {
|
|
if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet)) {
|
|
// Move this instruction
|
|
Instruction *InstToMove = L; ++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,
|
|
std::multimap<Value *, Value *> &LoadMoveSet,
|
|
Instruction *I) {
|
|
// Skip to the first instruction past I.
|
|
BasicBlock::iterator L = llvm::next(BasicBlock::iterator(I));
|
|
|
|
DenseSet<Value *> Users;
|
|
AliasSetTracker WriteSet(*AA);
|
|
|
|
// 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(); cast<Instruction>(L) != E; ++L) {
|
|
if (trackUsesOfI(Users, WriteSet, I, L)) {
|
|
if (L->mayReadFromMemory())
|
|
LoadMoveSet.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 trees 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,
|
|
std::multimap<Value *, Value *> &LoadMoveSet) {
|
|
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, 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) {
|
|
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.
|
|
std::vector<ValuePair> FlippedPairs;
|
|
FlippedPairs.reserve(ChosenPairs.size());
|
|
for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(),
|
|
E = ChosenPairs.end(); P != E; ++P)
|
|
FlippedPairs.push_back(ValuePair(P->second, P->first));
|
|
for (std::vector<ValuePair>::iterator P = FlippedPairs.begin(),
|
|
E = FlippedPairs.end(); P != E; ++P)
|
|
ChosenPairs.insert(*P);
|
|
|
|
std::multimap<Value *, Value *> LoadMoveSet;
|
|
collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet);
|
|
|
|
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, LoadMoveSet, I, J)) {
|
|
DEBUG(dbgs() << "BBV: fusion of: " << *I <<
|
|
" <-> " << *J <<
|
|
" aborted because of non-trivial dependency cycle\n");
|
|
--NumFusedOps;
|
|
++PI;
|
|
continue;
|
|
}
|
|
|
|
bool FlipMemInputs;
|
|
unsigned NumOperands = I->getNumOperands();
|
|
SmallVector<Value *, 3> ReplacedOperands(NumOperands);
|
|
getReplacementInputsForPair(Context, I, J, ReplacedOperands,
|
|
FlipMemInputs);
|
|
|
|
// Make a copy of the original operation, change its type to the vector
|
|
// type and replace its operands with the vector operands.
|
|
Instruction *K = I->clone();
|
|
if (I->hasName()) K->takeName(I);
|
|
|
|
if (!isa<StoreInst>(K))
|
|
K->mutateType(getVecTypeForPair(I->getType()));
|
|
|
|
for (unsigned o = 0; o < NumOperands; ++o)
|
|
K->setOperand(o, ReplacedOperands[o]);
|
|
|
|
// If we've flipped the memory inputs, make sure that we take the correct
|
|
// alignment.
|
|
if (FlipMemInputs) {
|
|
if (isa<StoreInst>(K))
|
|
cast<StoreInst>(K)->setAlignment(cast<StoreInst>(J)->getAlignment());
|
|
else
|
|
cast<LoadInst>(K)->setAlignment(cast<LoadInst>(J)->getAlignment());
|
|
}
|
|
|
|
K->insertAfter(J);
|
|
|
|
// Instruction insertion point:
|
|
Instruction *InsertionPt = K;
|
|
Instruction *K1 = 0, *K2 = 0;
|
|
replaceOutputsOfPair(Context, I, J, K, InsertionPt, K1, K2,
|
|
FlipMemInputs);
|
|
|
|
// The use tree of the first original instruction must be moved to after
|
|
// the location of the second instruction. The entire use tree of the
|
|
// first instruction is disjoint from the input tree of the second
|
|
// (by definition), and so commutes with it.
|
|
|
|
moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J);
|
|
|
|
if (!isa<StoreInst>(I)) {
|
|
I->replaceAllUsesWith(K1);
|
|
J->replaceAllUsesWith(K2);
|
|
AA->replaceWithNewValue(I, K1);
|
|
AA->replaceWithNewValue(J, 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;
|
|
VPIteratorPair IPairRange = LoadMoveSet.equal_range(I);
|
|
VPIteratorPair JPairRange = LoadMoveSet.equal_range(J);
|
|
for (std::multimap<Value *, Value *>::iterator N = IPairRange.first;
|
|
N != IPairRange.second; ++N)
|
|
NewSetMembers.push_back(ValuePair(K, N->second));
|
|
for (std::multimap<Value *, Value *>::iterator N = JPairRange.first;
|
|
N != JPairRange.second; ++N)
|
|
NewSetMembers.push_back(ValuePair(K, N->second));
|
|
for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(),
|
|
AE = NewSetMembers.end(); A != AE; ++A)
|
|
LoadMoveSet.insert(*A);
|
|
}
|
|
|
|
// Before removing I, set the iterator to the next instruction.
|
|
PI = llvm::next(BasicBlock::iterator(I));
|
|
if (cast<Instruction>(PI) == J)
|
|
++PI;
|
|
|
|
SE->forgetValue(I);
|
|
SE->forgetValue(J);
|
|
I->eraseFromParent();
|
|
J->eraseFromParent();
|
|
}
|
|
|
|
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_AG_DEPENDENCY(AliasAnalysis)
|
|
INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
|
|
INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
|
|
|
|
BasicBlockPass *llvm::createBBVectorizePass() {
|
|
return new BBVectorize();
|
|
}
|
|
|