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

Detailed Description

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.

Constructor & Destructor Documentation

◆ RuntimePointerChecking()

llvm::RuntimePointerChecking::RuntimePointerChecking	(	MemoryDepChecker &	DC,
		ScalarEvolution *	SE
	)

inline

Definition at line 418 of file LoopAccessAnalysis.h.

Member Function Documentation

◆ arePointersInSamePartition()

bool RuntimePointerChecking::arePointersInSamePartition	(	const SmallVectorImpl< int > &	PtrToPartition,
		unsigned	PtrIdx1,
		unsigned	PtrIdx2
	)

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.

◆ empty()

bool llvm::RuntimePointerChecking::empty ( ) const

inline

No run-time memory checking is necessary.

Definition at line 438 of file LoopAccessAnalysis.h.

References Pointers.

◆ generateChecks()

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().

◆ getChecks()

const SmallVectorImpl< RuntimePointerCheck > & llvm::RuntimePointerChecking::getChecks ( ) const

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().

◆ getDiffChecks()

std::optional< ArrayRef< PointerDiffInfo > > llvm::RuntimePointerChecking::getDiffChecks ( ) const

inline

Definition at line 456 of file LoopAccessAnalysis.h.

Referenced by llvm::LoopVectorizationPlanner::executePlan().

◆ getNumberOfChecks()

unsigned llvm::RuntimePointerChecking::getNumberOfChecks ( ) const

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().

◆ getPointerInfo()

const PointerInfo & llvm::RuntimePointerChecking::getPointerInfo ( unsigned PtrIdx ) const

inline

Return PointerInfo for pointer at index PtrIdx.

Definition at line 501 of file LoopAccessAnalysis.h.

References Pointers.

Referenced by llvm::LoopVersioning::prepareNoAliasMetadata().

◆ getSE()

ScalarEvolution * llvm::RuntimePointerChecking::getSE ( ) const

inline

Definition at line 505 of file LoopAccessAnalysis.h.

◆ insert()

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().

◆ needsChecking() [1/2]

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().

◆ needsChecking() [2/2]

bool RuntimePointerChecking::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.

Definition at line 561 of file LoopAccessAnalysis.cpp.

References llvm::RuntimePointerChecking::PointerInfo::AliasSetId, llvm::RuntimePointerChecking::PointerInfo::DependencySetId, I, llvm::RuntimePointerChecking::PointerInfo::IsWritePtr, and Pointers.

◆ print()

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().

◆ 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().

◆ reset()

void llvm::RuntimePointerChecking::reset ( )

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.

Friends And Related Function Documentation

◆ RuntimeCheckingPtrGroup

friend struct RuntimeCheckingPtrGroup

friend

Definition at line 386 of file LoopAccessAnalysis.h.

Member Data Documentation

◆ CheckingGroups

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().

◆ Need

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().

◆ Pointers

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().

The documentation for this class was generated from the following files:

include/llvm/Analysis/LoopAccessAnalysis.h
lib/Analysis/LoopAccessAnalysis.cpp

Classes

Public Member Functions

Static Public Member Functions

Public Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ RuntimePointerChecking()

Member Function Documentation

◆ arePointersInSamePartition()

◆ empty()

◆ generateChecks()

◆ getChecks()

◆ getDiffChecks()

◆ getNumberOfChecks()

◆ getPointerInfo()

◆ getSE()

◆ insert()

◆ needsChecking() [1/2]

◆ needsChecking() [2/2]

◆ print()

◆ printChecks()

◆ reset()

Friends And Related Function Documentation

◆ RuntimeCheckingPtrGroup

Member Data Documentation

◆ CheckingGroups

◆ Need

◆ Pointers