LLVM 17.0.0git
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Holds information about the memory runtime legality checks to verify that a group of pointers do not overlap. More...
#include "llvm/Analysis/LoopAccessAnalysis.h"
Classes | |
struct | PointerInfo |
Public Member Functions | |
RuntimePointerChecking (MemoryDepChecker &DC, ScalarEvolution *SE) | |
void | reset () |
Reset the state of the pointer runtime information. | |
void | insert (Loop *Lp, Value *Ptr, const SCEV *PtrExpr, Type *AccessTy, bool WritePtr, unsigned DepSetId, unsigned ASId, PredicatedScalarEvolution &PSE, bool NeedsFreeze) |
Insert a pointer and calculate the start and end SCEVs. | |
bool | empty () const |
No run-time memory checking is necessary. | |
void | generateChecks (MemoryDepChecker::DepCandidates &DepCands, bool UseDependencies) |
Generate the checks and store it. | |
const SmallVectorImpl< RuntimePointerCheck > & | getChecks () const |
Returns the checks that generateChecks created. | |
std::optional< ArrayRef< PointerDiffInfo > > | getDiffChecks () const |
bool | needsChecking (const RuntimeCheckingPtrGroup &M, const RuntimeCheckingPtrGroup &N) const |
Decide if we need to add a check between two groups of pointers, according to needsChecking. | |
unsigned | getNumberOfChecks () const |
Returns the number of run-time checks required according to needsChecking. | |
void | print (raw_ostream &OS, unsigned Depth=0) const |
Print the list run-time memory checks necessary. | |
void | printChecks (raw_ostream &OS, const SmallVectorImpl< RuntimePointerCheck > &Checks, unsigned Depth=0) const |
Print Checks . | |
bool | needsChecking (unsigned I, unsigned J) const |
Decide whether we need to issue a run-time check for pointer at index I and J to prove their independence. | |
const PointerInfo & | getPointerInfo (unsigned PtrIdx) const |
Return PointerInfo for pointer at index PtrIdx . | |
ScalarEvolution * | getSE () const |
Static Public Member Functions | |
static bool | arePointersInSamePartition (const SmallVectorImpl< int > &PtrToPartition, unsigned PtrIdx1, unsigned PtrIdx2) |
Check if pointers are in the same partition. | |
Public Attributes | |
bool | Need = false |
This flag indicates if we need to add the runtime check. | |
SmallVector< PointerInfo, 2 > | Pointers |
Information about the pointers that may require checking. | |
SmallVector< RuntimeCheckingPtrGroup, 2 > | CheckingGroups |
Holds a partitioning of pointers into "check groups". | |
Friends | |
struct | RuntimeCheckingPtrGroup |
Holds information about the memory runtime legality checks to verify that a group of pointers do not overlap.
Definition at line 385 of file LoopAccessAnalysis.h.
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inline |
Definition at line 418 of file LoopAccessAnalysis.h.
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static |
Check if pointers are in the same partition.
PtrToPartition
contains the partition number for pointers (-1 if the pointer belongs to multiple partitions).
Definition at line 554 of file LoopAccessAnalysis.cpp.
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inline |
No run-time memory checking is necessary.
Definition at line 438 of file LoopAccessAnalysis.h.
References Pointers.
void RuntimePointerChecking::generateChecks | ( | MemoryDepChecker::DepCandidates & | DepCands, |
bool | UseDependencies | ||
) |
Generate the checks and store it.
This also performs the grouping of pointers to reduce the number of memchecks necessary.
Definition at line 359 of file LoopAccessAnalysis.cpp.
References assert(), llvm::SmallVectorBase< Size_T >::empty(), and generateChecks().
Referenced by generateChecks().
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inline |
Returns the checks that generateChecks created.
They can be used to ensure no read/write accesses overlap across all loop iterations.
Definition at line 447 of file LoopAccessAnalysis.h.
Referenced by llvm::LoopVectorizationPlanner::executePlan().
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inline |
Definition at line 456 of file LoopAccessAnalysis.h.
Referenced by llvm::LoopVectorizationPlanner::executePlan().
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inline |
Returns the number of run-time checks required according to needsChecking.
Definition at line 469 of file LoopAccessAnalysis.h.
References llvm::SmallVectorBase< Size_T >::size().
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inline |
Return PointerInfo for pointer at index PtrIdx
.
Definition at line 501 of file LoopAccessAnalysis.h.
References Pointers.
Referenced by llvm::LoopVersioning::prepareNoAliasMetadata().
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inline |
Definition at line 505 of file LoopAccessAnalysis.h.
void RuntimePointerChecking::insert | ( | Loop * | Lp, |
Value * | Ptr, | ||
const SCEV * | PtrExpr, | ||
Type * | AccessTy, | ||
bool | WritePtr, | ||
unsigned | DepSetId, | ||
unsigned | ASId, | ||
PredicatedScalarEvolution & | PSE, | ||
bool | NeedsFreeze | ||
) |
Insert a pointer and calculate the start and end SCEVs.
Calculate Start and End points of memory access.
We need PSE
in order to compute the SCEV expression of the pointer according to the assumptions that we've made during the analysis. The method might also version the pointer stride according to Strides
, and add new predicates to PSE
.
Let's assume A is the first access and B is a memory access on N-th loop iteration. Then B is calculated as: B = A + Step*N . Step value may be positive or negative. N is a calculated back-edge taken count: N = (TripCount > 0) ? RoundDown(TripCount -1 , VF) : 0 Start and End points are calculated in the following way: Start = UMIN(A, B) ; End = UMAX(A, B) + SizeOfElt, where SizeOfElt is the size of single memory access in bytes.
There is no conflict when the intervals are disjoint: NoConflict = (P2.Start >= P1.End) || (P1.Start >= P2.End)
Definition at line 208 of file LoopAccessAnalysis.cpp.
References assert(), DL, llvm::SCEVAddRecExpr::evaluateAtIteration(), llvm::ScalarEvolution::getAddExpr(), llvm::PredicatedScalarEvolution::getBackedgeTakenCount(), llvm::Module::getDataLayout(), llvm::LoopBase< BlockT, LoopT >::getHeader(), llvm::BasicBlock::getModule(), llvm::PredicatedScalarEvolution::getSE(), llvm::SCEVAddRecExpr::getStart(), llvm::SCEVAddRecExpr::getStepRecurrence(), llvm::ScalarEvolution::getStoreSizeOfExpr(), llvm::ScalarEvolution::getUMaxExpr(), llvm::ScalarEvolution::getUMinExpr(), llvm::ScalarEvolution::isLoopInvariant(), Pointers, Ptr, and std::swap().
bool RuntimePointerChecking::needsChecking | ( | const RuntimeCheckingPtrGroup & | M, |
const RuntimeCheckingPtrGroup & | N | ||
) | const |
Decide if we need to add a check between two groups of pointers, according to needsChecking.
Definition at line 366 of file LoopAccessAnalysis.cpp.
References I, N, and needsChecking().
Referenced by needsChecking().
Decide whether we need to issue a run-time check for pointer at index I
and J
to prove their independence.
Definition at line 561 of file LoopAccessAnalysis.cpp.
References llvm::RuntimePointerChecking::PointerInfo::AliasSetId, llvm::RuntimePointerChecking::PointerInfo::DependencySetId, I, llvm::RuntimePointerChecking::PointerInfo::IsWritePtr, and Pointers.
void RuntimePointerChecking::print | ( | raw_ostream & | OS, |
unsigned | Depth = 0 |
||
) | const |
Print the list run-time memory checks necessary.
Definition at line 599 of file LoopAccessAnalysis.cpp.
References CheckingGroups, llvm::Depth, I, llvm::raw_ostream::indent(), OS, Pointers, and printChecks().
void RuntimePointerChecking::printChecks | ( | raw_ostream & | OS, |
const SmallVectorImpl< RuntimePointerCheck > & | Checks, | ||
unsigned | Depth = 0 |
||
) | const |
Print Checks
.
Definition at line 580 of file LoopAccessAnalysis.cpp.
References Check, llvm::Depth, llvm::raw_ostream::indent(), N, OS, and Pointers.
Referenced by print().
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inline |
Reset the state of the pointer runtime information.
Definition at line 422 of file LoopAccessAnalysis.h.
References llvm::SmallVectorImpl< T >::clear(), Need, and Pointers.
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friend |
Definition at line 386 of file LoopAccessAnalysis.h.
SmallVector<RuntimeCheckingPtrGroup, 2> llvm::RuntimePointerChecking::CheckingGroups |
Holds a partitioning of pointers into "check groups".
Definition at line 486 of file LoopAccessAnalysis.h.
Referenced by llvm::LoopVersioning::prepareNoAliasMetadata(), and print().
bool llvm::RuntimePointerChecking::Need = false |
This flag indicates if we need to add the runtime check.
Definition at line 480 of file LoopAccessAnalysis.h.
Referenced by llvm::LoopVectorizationLegality::canVectorize(), llvm::LoopVectorizationCostModel::computeMaxVF(), reset(), llvm::LoopVectorizationCostModel::runtimeChecksRequired(), and llvm::LoopVectorizationCostModel::selectInterleaveCount().
SmallVector<PointerInfo, 2> llvm::RuntimePointerChecking::Pointers |
Information about the pointers that may require checking.
Definition at line 483 of file LoopAccessAnalysis.h.
Referenced by llvm::RuntimeCheckingPtrGroup::addPointer(), empty(), getPointerInfo(), insert(), needsChecking(), print(), printChecks(), and reset().