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[LAA] Lift RuntimePointerCheck out of LoopAccessInfo, NFC 

I am planning to add more nested classes inside RuntimePointerCheck so
all these triple-nesting would be hard to follow.

Also rename it to RuntimePointerChecking (i.e. append 'ing').

llvm-svn: 242218
This commit is contained in:
Adam Nemet 2015-07-14 22:32:44 +00:00
parent 9bbad03b98
commit 7cdebac0c8
5 changed files with 172 additions and 175 deletions
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61
llvm/include/llvm/Analysis/LoopAccessAnalysis.h
View File

@ -292,26 +292,10 @@ private:
bool couldPreventStoreLoadForward(unsigned Distance, unsigned TypeByteSize);
};
/// \brief Drive the analysis of memory accesses in the loop
///
/// This class is responsible for analyzing the memory accesses of a loop. It
/// collects the accesses and then its main helper the AccessAnalysis class
/// finds and categorizes the dependences in buildDependenceSets.
///
/// For memory dependences that can be analyzed at compile time, it determines
/// whether the dependence is part of cycle inhibiting vectorization. This work
/// is delegated to the MemoryDepChecker class.
///
/// For memory dependences that cannot be determined at compile time, it
/// generates run-time checks to prove independence. This is done by
/// AccessAnalysis::canCheckPtrAtRT and the checks are maintained by the
/// RuntimePointerCheck class.
class LoopAccessInfo {
public:
/// This struct holds information about the memory runtime legality check that
/// a group of pointers do not overlap.
struct RuntimePointerCheck {
RuntimePointerCheck(ScalarEvolution *SE) : Need(false), SE(SE) {}
/// This struct holds information about the memory runtime legality check that
/// a group of pointers do not overlap.
struct RuntimePointerChecking {
RuntimePointerChecking(ScalarEvolution *SE) : Need(false), SE(SE) {}
/// Reset the state of the pointer runtime information.
void reset() {
@ -337,7 +321,7 @@ public:
struct CheckingPtrGroup {
/// \brief Create a new pointer checking group containing a single
/// pointer, with index \p Index in RtCheck.
CheckingPtrGroup(unsigned Index, RuntimePointerCheck &RtCheck)
CheckingPtrGroup(unsigned Index, RuntimePointerChecking &RtCheck)
: RtCheck(RtCheck), High(RtCheck.Ends[Index]),
Low(RtCheck.Starts[Index]) {
Members.push_back(Index);
@ -353,7 +337,7 @@ public:
/// Constitutes the context of this pointer checking group. For each
/// pointer that is a member of this group we will retain the index
/// at which it appears in RtCheck.
RuntimePointerCheck &RtCheck;
RuntimePointerChecking &RtCheck;
/// The SCEV expression which represents the upper bound of all the
/// pointers in this group.
const SCEV *High;
@ -382,8 +366,7 @@ public:
/// \brief Decide if we need to add a check between two groups of pointers,
/// according to needsChecking.
bool needsChecking(const CheckingPtrGroup &M,
const CheckingPtrGroup &N,
bool needsChecking(const CheckingPtrGroup &M, const CheckingPtrGroup &N,
const SmallVectorImpl<int> *PtrPartition) const;
/// \brief Return true if any pointer requires run-time checking according
@ -407,9 +390,9 @@ public:
/// Holds the pointers that we need to check.
SmallVector<TrackingVH<Value>, 2> Pointers;
/// Holds the pointer value at the beginning of the loop.
SmallVector<const SCEV*, 2> Starts;
SmallVector<const SCEV *, 2> Starts;
/// Holds the pointer value at the end of the loop.
SmallVector<const SCEV*, 2> Ends;
SmallVector<const SCEV *, 2> Ends;
/// Holds the information if this pointer is used for writing to memory.
SmallVector<bool, 2> IsWritePtr;
/// Holds the id of the set of pointers that could be dependent because of a
@ -423,8 +406,24 @@ public:
SmallVector<CheckingPtrGroup, 2> CheckingGroups;
/// Holds a pointer to the ScalarEvolution analysis.
ScalarEvolution *SE;
};
};
/// \brief Drive the analysis of memory accesses in the loop
///
/// This class is responsible for analyzing the memory accesses of a loop. It
/// collects the accesses and then its main helper the AccessAnalysis class
/// finds and categorizes the dependences in buildDependenceSets.
///
/// For memory dependences that can be analyzed at compile time, it determines
/// whether the dependence is part of cycle inhibiting vectorization. This work
/// is delegated to the MemoryDepChecker class.
///
/// For memory dependences that cannot be determined at compile time, it
/// generates run-time checks to prove independence. This is done by
/// AccessAnalysis::canCheckPtrAtRT and the checks are maintained by the
/// RuntimePointerCheck class.
class LoopAccessInfo {
public:
LoopAccessInfo(Loop *L, ScalarEvolution *SE, const DataLayout &DL,
const TargetLibraryInfo *TLI, AliasAnalysis *AA,
DominatorTree *DT, LoopInfo *LI,
@ -434,15 +433,15 @@ public:
/// no memory dependence cycles.
bool canVectorizeMemory() const { return CanVecMem; }
const RuntimePointerCheck *getRuntimePointerCheck() const {
return &PtrRtCheck;
const RuntimePointerChecking *getRuntimePointerChecking() const {
return &PtrRtChecking;
}
/// \brief Number of memchecks required to prove independence of otherwise
/// may-alias pointers.
unsigned getNumRuntimePointerChecks(
const SmallVectorImpl<int> *PtrPartition = nullptr) const {
return PtrRtCheck.getNumberOfChecks(PtrPartition);
return PtrRtChecking.getNumberOfChecks(PtrPartition);
}
/// Return true if the block BB needs to be predicated in order for the loop
@ -512,7 +511,7 @@ private:
/// We need to check that all of the pointers in this list are disjoint
/// at runtime.
RuntimePointerCheck PtrRtCheck;
RuntimePointerChecking PtrRtChecking;
/// \brief the Memory Dependence Checker which can determine the
/// loop-independent and loop-carried dependences between memory accesses.

80
llvm/lib/Analysis/LoopAccessAnalysis.cpp
View File

@ -119,8 +119,8 @@ const SCEV *llvm::replaceSymbolicStrideSCEV(ScalarEvolution *SE,
return SE->getSCEV(Ptr);
}
void LoopAccessInfo::RuntimePointerCheck::insert(
Loop *Lp, Value *Ptr, bool WritePtr, unsigned DepSetId, unsigned ASId,
void RuntimePointerChecking::insert(Loop *Lp, Value *Ptr, bool WritePtr,
unsigned DepSetId, unsigned ASId,
const ValueToValueMap &Strides) {
// Get the stride replaced scev.
const SCEV *Sc = replaceSymbolicStrideSCEV(SE, Strides, Ptr);
@ -137,7 +137,7 @@ void LoopAccessInfo::RuntimePointerCheck::insert(
Exprs.push_back(Sc);
}
bool LoopAccessInfo::RuntimePointerCheck::needsChecking(
bool RuntimePointerChecking::needsChecking(
const CheckingPtrGroup &M, const CheckingPtrGroup &N,
const SmallVectorImpl<int> *PtrPartition) const {
for (unsigned I = 0, EI = M.Members.size(); EI != I; ++I)
@ -161,8 +161,7 @@ static const SCEV *getMinFromExprs(const SCEV *I, const SCEV *J,
return I;
}
bool LoopAccessInfo::RuntimePointerCheck::CheckingPtrGroup::addPointer(
unsigned Index) {
bool RuntimePointerChecking::CheckingPtrGroup::addPointer(unsigned Index) {
// Compare the starts and ends with the known minimum and maximum
// of this set. We need to know how we compare against the min/max
// of the set in order to be able to emit memchecks.
@ -186,9 +185,8 @@ bool LoopAccessInfo::RuntimePointerCheck::CheckingPtrGroup::addPointer(
return true;
}
void LoopAccessInfo::RuntimePointerCheck::groupChecks(
MemoryDepChecker::DepCandidates &DepCands,
bool UseDependencies) {
void RuntimePointerChecking::groupChecks(
MemoryDepChecker::DepCandidates &DepCands, bool UseDependencies) {
// We build the groups from dependency candidates equivalence classes
// because:
// - We know that pointers in the same equivalence class share
@ -283,7 +281,7 @@ void LoopAccessInfo::RuntimePointerCheck::groupChecks(
}
}
bool LoopAccessInfo::RuntimePointerCheck::needsChecking(
bool RuntimePointerChecking::needsChecking(
unsigned I, unsigned J, const SmallVectorImpl<int> *PtrPartition) const {
// No need to check if two readonly pointers intersect.
if (!IsWritePtr[I] && !IsWritePtr[J])
@ -307,7 +305,7 @@ bool LoopAccessInfo::RuntimePointerCheck::needsChecking(
return true;
}
void LoopAccessInfo::RuntimePointerCheck::print(
void RuntimePointerChecking::print(
raw_ostream &OS, unsigned Depth,
const SmallVectorImpl<int> *PtrPartition) const {
@ -353,7 +351,7 @@ void LoopAccessInfo::RuntimePointerCheck::print(
}
}
unsigned LoopAccessInfo::RuntimePointerCheck::getNumberOfChecks(
unsigned RuntimePointerChecking::getNumberOfChecks(
const SmallVectorImpl<int> *PtrPartition) const {
unsigned NumPartitions = CheckingGroups.size();
@ -366,7 +364,7 @@ unsigned LoopAccessInfo::RuntimePointerCheck::getNumberOfChecks(
return CheckCount;
}
bool LoopAccessInfo::RuntimePointerCheck::needsAnyChecking(
bool RuntimePointerChecking::needsAnyChecking(
const SmallVectorImpl<int> *PtrPartition) const {
unsigned NumPointers = Pointers.size();
@ -414,9 +412,8 @@ public:
///
/// Returns true if we need no check or if we do and we can generate them
/// (i.e. the pointers have computable bounds).
bool canCheckPtrAtRT(LoopAccessInfo::RuntimePointerCheck &RtCheck,
ScalarEvolution *SE, Loop *TheLoop,
const ValueToValueMap &Strides,
bool canCheckPtrAtRT(RuntimePointerChecking &RtCheck, ScalarEvolution *SE,
Loop *TheLoop, const ValueToValueMap &Strides,
bool ShouldCheckStride = false);
/// \brief Goes over all memory accesses, checks whether a RT check is needed
@ -492,9 +489,10 @@ static bool hasComputableBounds(ScalarEvolution *SE,
return AR->isAffine();
}
bool AccessAnalysis::canCheckPtrAtRT(
LoopAccessInfo::RuntimePointerCheck &RtCheck, ScalarEvolution *SE,
Loop *TheLoop, const ValueToValueMap &StridesMap, bool ShouldCheckStride) {
bool AccessAnalysis::canCheckPtrAtRT(RuntimePointerChecking &RtCheck,
ScalarEvolution *SE, Loop *TheLoop,
const ValueToValueMap &StridesMap,
bool ShouldCheckStride) {
// Find pointers with computable bounds. We are going to use this information
// to place a runtime bound check.
bool CanDoRT = true;
@ -1320,8 +1318,8 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
unsigned NumReads = 0;
unsigned NumReadWrites = 0;
PtrRtCheck.Pointers.clear();
PtrRtCheck.Need = false;
PtrRtChecking.Pointers.clear();
PtrRtChecking.Need = false;
const bool IsAnnotatedParallel = TheLoop->isAnnotatedParallel();
@ -1481,7 +1479,7 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
// Find pointers with computable bounds. We are going to use this information
// to place a runtime bound check.
bool CanDoRTIfNeeded =
Accesses.canCheckPtrAtRT(PtrRtCheck, SE, TheLoop, Strides);
Accesses.canCheckPtrAtRT(PtrRtChecking, SE, TheLoop, Strides);
if (!CanDoRTIfNeeded) {
emitAnalysis(LoopAccessReport() << "cannot identify array bounds");
DEBUG(dbgs() << "LAA: We can't vectorize because we can't find "
@ -1505,11 +1503,11 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
// Clear the dependency checks. We assume they are not needed.
Accesses.resetDepChecks(DepChecker);
PtrRtCheck.reset();
PtrRtCheck.Need = true;
PtrRtChecking.reset();
PtrRtChecking.Need = true;
CanDoRTIfNeeded =
Accesses.canCheckPtrAtRT(PtrRtCheck, SE, TheLoop, Strides, true);
Accesses.canCheckPtrAtRT(PtrRtChecking, SE, TheLoop, Strides, true);
// Check that we found the bounds for the pointer.
if (!CanDoRTIfNeeded) {
@ -1526,7 +1524,7 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
if (CanVecMem)
DEBUG(dbgs() << "LAA: No unsafe dependent memory operations in loop. We"
<< (PtrRtCheck.Need ? "" : " don't")
<< (PtrRtChecking.Need ? "" : " don't")
<< " need runtime memory checks.\n");
else {
emitAnalysis(LoopAccessReport() <<
@ -1566,7 +1564,7 @@ static Instruction *getFirstInst(Instruction *FirstInst, Value *V,
std::pair<Instruction *, Instruction *> LoopAccessInfo::addRuntimeCheck(
Instruction *Loc, const SmallVectorImpl<int> *PtrPartition) const {
if (!PtrRtCheck.Need)
if (!PtrRtChecking.Need)
return std::make_pair(nullptr, nullptr);
SmallVector<TrackingVH<Value>, 2> Starts;
@ -1576,10 +1574,10 @@ std::pair<Instruction *, Instruction *> LoopAccessInfo::addRuntimeCheck(
SCEVExpander Exp(*SE, DL, "induction");
Instruction *FirstInst = nullptr;
for (unsigned i = 0; i < PtrRtCheck.CheckingGroups.size(); ++i) {
const RuntimePointerCheck::CheckingPtrGroup &CG =
PtrRtCheck.CheckingGroups[i];
Value *Ptr = PtrRtCheck.Pointers[CG.Members[0]];
for (unsigned i = 0; i < PtrRtChecking.CheckingGroups.size(); ++i) {
const RuntimePointerChecking::CheckingPtrGroup &CG =
PtrRtChecking.CheckingGroups[i];
Value *Ptr = PtrRtChecking.Pointers[CG.Members[0]];
const SCEV *Sc = SE->getSCEV(Ptr);
if (SE->isLoopInvariant(Sc, TheLoop)) {
@ -1606,14 +1604,14 @@ std::pair<Instruction *, Instruction *> LoopAccessInfo::addRuntimeCheck(
IRBuilder<> ChkBuilder(Loc);
// Our instructions might fold to a constant.
Value *MemoryRuntimeCheck = nullptr;
for (unsigned i = 0; i < PtrRtCheck.CheckingGroups.size(); ++i) {
for (unsigned j = i + 1; j < PtrRtCheck.CheckingGroups.size(); ++j) {
const RuntimePointerCheck::CheckingPtrGroup &CGI =
PtrRtCheck.CheckingGroups[i];
const RuntimePointerCheck::CheckingPtrGroup &CGJ =
PtrRtCheck.CheckingGroups[j];
for (unsigned i = 0; i < PtrRtChecking.CheckingGroups.size(); ++i) {
for (unsigned j = i + 1; j < PtrRtChecking.CheckingGroups.size(); ++j) {
const RuntimePointerChecking::CheckingPtrGroup &CGI =
PtrRtChecking.CheckingGroups[i];
const RuntimePointerChecking::CheckingPtrGroup &CGJ =
PtrRtChecking.CheckingGroups[j];
if (!PtrRtCheck.needsChecking(CGI, CGJ, PtrPartition))
if (!PtrRtChecking.needsChecking(CGI, CGJ, PtrPartition))
continue;
unsigned AS0 = Starts[i]->getType()->getPointerAddressSpace();
@ -1664,8 +1662,8 @@ LoopAccessInfo::LoopAccessInfo(Loop *L, ScalarEvolution *SE,
const TargetLibraryInfo *TLI, AliasAnalysis *AA,
DominatorTree *DT, LoopInfo *LI,
const ValueToValueMap &Strides)
: PtrRtCheck(SE), DepChecker(SE, L), TheLoop(L), SE(SE), DL(DL), TLI(TLI),
AA(AA), DT(DT), LI(LI), NumLoads(0), NumStores(0),
: PtrRtChecking(SE), DepChecker(SE, L), TheLoop(L), SE(SE), DL(DL),
TLI(TLI), AA(AA), DT(DT), LI(LI), NumLoads(0), NumStores(0),
MaxSafeDepDistBytes(-1U), CanVecMem(false),
StoreToLoopInvariantAddress(false) {
if (canAnalyzeLoop())
@ -1674,7 +1672,7 @@ LoopAccessInfo::LoopAccessInfo(Loop *L, ScalarEvolution *SE,
void LoopAccessInfo::print(raw_ostream &OS, unsigned Depth) const {
if (CanVecMem) {
if (PtrRtCheck.Need)
if (PtrRtChecking.Need)
OS.indent(Depth) << "Memory dependences are safe with run-time checks\n";
else
OS.indent(Depth) << "Memory dependences are safe\n";
@ -1693,7 +1691,7 @@ void LoopAccessInfo::print(raw_ostream &OS, unsigned Depth) const {
OS.indent(Depth) << "Too many interesting dependences, not recorded\n";
// List the pair of accesses need run-time checks to prove independence.
PtrRtCheck.print(OS, Depth);
PtrRtChecking.print(OS, Depth);
OS << "\n";
OS.indent(Depth) << "Store to invariant address was "

5
llvm/lib/Transforms/Scalar/LoopDistribute.cpp
View File

@ -432,8 +432,7 @@ public:
/// partitions its entry is set to -1.
SmallVector<int, 8>
computePartitionSetForPointers(const LoopAccessInfo &LAI) {
const LoopAccessInfo::RuntimePointerCheck *RtPtrCheck =
LAI.getRuntimePointerCheck();
const RuntimePointerChecking *RtPtrCheck = LAI.getRuntimePointerChecking();
unsigned N = RtPtrCheck->Pointers.size();
SmallVector<int, 8> PtrToPartitions(N);
@ -753,7 +752,7 @@ private:
LoopVersioning LVer(LAI, L, LI, DT, &PtrToPartition);
if (LVer.needsRuntimeChecks()) {
DEBUG(dbgs() << "\nPointers:\n");
DEBUG(LAI.getRuntimePointerCheck()->print(dbgs(), 0, &PtrToPartition));
DEBUG(LAI.getRuntimePointerChecking()->print(dbgs(), 0, &PtrToPartition));
LVer.versionLoop(this);
LVer.addPHINodes(DefsUsedOutside);
}

2
llvm/lib/Transforms/Utils/LoopVersioning.cpp
View File

@ -32,7 +32,7 @@ LoopVersioning::LoopVersioning(const LoopAccessInfo &LAI, Loop *L, LoopInfo *LI,
}
bool LoopVersioning::needsRuntimeChecks() const {
return LAI.getRuntimePointerCheck()->needsAnyChecking(PtrToPartition);
return LAI.getRuntimePointerChecking()->needsAnyChecking(PtrToPartition);
}
void LoopVersioning::versionLoop(Pass *P) {

17
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
View File

@ -924,8 +924,8 @@ public:
bool isUniformAfterVectorization(Instruction* I) { return Uniforms.count(I); }
/// Returns the information that we collected about runtime memory check.
const LoopAccessInfo::RuntimePointerCheck *getRuntimePointerCheck() const {
return LAI->getRuntimePointerCheck();
const RuntimePointerChecking *getRuntimePointerChecking() const {
return LAI->getRuntimePointerChecking();
}
const LoopAccessInfo *getLAI() const {
@ -3873,10 +3873,11 @@ bool LoopVectorizationLegality::canVectorize() {
// Collect all of the variables that remain uniform after vectorization.
collectLoopUniforms();
DEBUG(dbgs() << "LV: We can vectorize this loop" <<
(LAI->getRuntimePointerCheck()->Need ? " (with a runtime bound check)" :
"")
<<"!\n");
DEBUG(dbgs() << "LV: We can vectorize this loop"
<< (LAI->getRuntimePointerChecking()->Need
? " (with a runtime bound check)"
: "")
<< "!\n");
// Analyze interleaved memory accesses.
if (EnableInterleavedMemAccesses)
@ -4449,7 +4450,7 @@ LoopVectorizationCostModel::VectorizationFactor
LoopVectorizationCostModel::selectVectorizationFactor(bool OptForSize) {
// Width 1 means no vectorize
VectorizationFactor Factor = { 1U, 0U };
if (OptForSize && Legal->getRuntimePointerCheck()->Need) {
if (OptForSize && Legal->getRuntimePointerChecking()->Need) {
emitAnalysis(VectorizationReport() <<
"runtime pointer checks needed. Enable vectorization of this "
"loop with '#pragma clang loop vectorize(enable)' when "
@ -4713,7 +4714,7 @@ unsigned LoopVectorizationCostModel::selectInterleaveCount(bool OptForSize,
// Note that if we've already vectorized the loop we will have done the
// runtime check and so interleaving won't require further checks.
bool InterleavingRequiresRuntimePointerCheck =
(VF == 1 && Legal->getRuntimePointerCheck()->Need);
(VF == 1 && Legal->getRuntimePointerChecking()->Need);
// We want to interleave small loops in order to reduce the loop overhead and
// potentially expose ILP opportunities.