Dependence - This class represents a dependence between two memory memory references in a function. More...

#include "llvm/Analysis/DependenceAnalysis.h"

Inheritance diagram for llvm::Dependence:

Classes
struct	DVEntry
	Dependence::DVEntry - Each level in the distance/direction vector has a direction (or perhaps a union of several directions), and perhaps a distance. More...

Public Member Functions
	Dependence (Instruction Source, Instruction Destination)

virtual	~Dependence ()=default

Instruction *	getSrc () const
	getSrc - Returns the source instruction for this dependence.

Instruction *	getDst () const
	getDst - Returns the destination instruction for this dependence.

bool	isInput () const
	isInput - Returns true if this is an input dependence.

bool	isOutput () const
	isOutput - Returns true if this is an output dependence.

bool	isFlow () const
	isFlow - Returns true if this is a flow (aka true) dependence.

bool	isAnti () const
	isAnti - Returns true if this is an anti dependence.

bool	isOrdered () const
	isOrdered - Returns true if dependence is Output, Flow, or Anti

bool	isUnordered () const
	isUnordered - Returns true if dependence is Input

virtual bool	isLoopIndependent () const
	isLoopIndependent - Returns true if this is a loop-independent dependence.

virtual bool	isConfused () const
	isConfused - Returns true if this dependence is confused (the compiler understands nothing and makes worst-case assumptions).

virtual bool	isConsistent () const
	isConsistent - Returns true if this dependence is consistent (occurs every time the source and destination are executed).

virtual unsigned	getLevels () const
	getLevels - Returns the number of common loops surrounding the source and destination of the dependence.

virtual unsigned	getDirection (unsigned Level) const
	getDirection - Returns the direction associated with a particular level.

virtual const SCEV *	getDistance (unsigned Level) const
	getDistance - Returns the distance (or NULL) associated with a particular level.

virtual bool	isDirectionNegative () const
	Check if the direction vector is negative.

virtual bool	normalize (ScalarEvolution *SE)
	If the direction vector is negative, normalize the direction vector to make it non-negative.

virtual bool	isPeelFirst (unsigned Level) const
	isPeelFirst - Returns true if peeling the first iteration from this loop will break this dependence.

virtual bool	isPeelLast (unsigned Level) const
	isPeelLast - Returns true if peeling the last iteration from this loop will break this dependence.

virtual bool	isSplitable (unsigned Level) const
	isSplitable - Returns true if splitting this loop will break the dependence.

virtual bool	isScalar (unsigned Level) const
	isScalar - Returns true if a particular level is scalar; that is, if no subscript in the source or destination mention the induction variable associated with the loop at this level.

const Dependence *	getNextPredecessor () const
	getNextPredecessor - Returns the value of the NextPredecessor field.

const Dependence *	getNextSuccessor () const
	getNextSuccessor - Returns the value of the NextSuccessor field.

void	setNextPredecessor (const Dependence *pred)
	setNextPredecessor - Sets the value of the NextPredecessor field.

void	setNextSuccessor (const Dependence *succ)
	setNextSuccessor - Sets the value of the NextSuccessor field.

void	dump (raw_ostream &OS) const
	dump - For debugging purposes, dumps a dependence to OS.

Protected Member Functions
	Dependence (Dependence &&)=default

Dependence &	operator= (Dependence &&)=default

Protected Attributes
Instruction *	Src

Instruction *	Dst

Friends
class	DependenceInfo

Detailed Description

Dependence - This class represents a dependence between two memory memory references in a function.

It contains minimal information and is used in the very common situation where the compiler is unable to determine anything beyond the existence of a dependence; that is, it represents a confused dependence (see also FullDependence). In most cases (for output, flow, and anti dependences), the dependence implies an ordering, where the source must precede the destination; in contrast, input dependences are unordered.

When a dependence graph is built, each Dependence will be a member of the set of predecessor edges for its destination instruction and a set if successor edges for its source instruction. These sets are represented as singly-linked lists, with the "next" fields stored in the dependence itelf.

Definition at line 71 of file DependenceAnalysis.h.

Constructor & Destructor Documentation

◆ Dependence() [1/2]

llvm::Dependence::Dependence ( Dependence && )

protecteddefault

◆ Dependence() [2/2]

llvm::Dependence::Dependence	(	Instruction *	Source,
		Instruction *	Destination
	)

inline

Definition at line 77 of file DependenceAnalysis.h.

◆ ~Dependence()

virtual llvm::Dependence::~Dependence ( )

virtualdefault

Member Function Documentation

◆ dump()

void Dependence::dump ( raw_ostream & OS ) const

dump - For debugging purposes, dumps a dependence to OS.

Definition at line 656 of file DependenceAnalysis.cpp.

References llvm::Dependence::DVEntry::ALL, llvm::Dependence::DVEntry::EQ, getDirection(), getDistance(), getLevels(), llvm::Dependence::DVEntry::GT, isAnti(), isConfused(), isConsistent(), isFlow(), isInput(), isLoopIndependent(), isOutput(), isPeelFirst(), isPeelLast(), isScalar(), isSplitable(), llvm::Dependence::DVEntry::LT, and OS.

Referenced by llvm::FullDependence::normalize().

◆ getDirection()

virtual unsigned llvm::Dependence::getDirection ( unsigned Level ) const

inlinevirtual

getDirection - Returns the direction associated with a particular level.

Reimplemented in llvm::FullDependence.

Definition at line 157 of file DependenceAnalysis.h.

References llvm::Dependence::DVEntry::ALL.

Referenced by dump().

◆ getDistance()

virtual const SCEV * llvm::Dependence::getDistance ( unsigned Level ) const

inlinevirtual

getDistance - Returns the distance (or NULL) associated with a particular level.

Reimplemented in llvm::FullDependence.

Definition at line 161 of file DependenceAnalysis.h.

Referenced by dump().

◆ getDst()

Instruction * llvm::Dependence::getDst ( ) const

inline

getDst - Returns the destination instruction for this dependence.

Definition at line 112 of file DependenceAnalysis.h.

References Dst.

Referenced by llvm::DependenceInfo::getSplitIteration().

◆ getLevels()

virtual unsigned llvm::Dependence::getLevels ( ) const

inlinevirtual

getLevels - Returns the number of common loops surrounding the source and destination of the dependence.

Reimplemented in llvm::FullDependence.

Definition at line 153 of file DependenceAnalysis.h.

Referenced by dump().

◆ getNextPredecessor()

const Dependence * llvm::Dependence::getNextPredecessor ( ) const

inline

getNextPredecessor - Returns the value of the NextPredecessor field.

Definition at line 192 of file DependenceAnalysis.h.

◆ getNextSuccessor()

const Dependence * llvm::Dependence::getNextSuccessor ( ) const

inline

getNextSuccessor - Returns the value of the NextSuccessor field.

Definition at line 196 of file DependenceAnalysis.h.

◆ getSrc()

Instruction * llvm::Dependence::getSrc ( ) const

inline

getSrc - Returns the source instruction for this dependence.

Definition at line 108 of file DependenceAnalysis.h.

References Src.

Referenced by llvm::DependenceInfo::getSplitIteration().

◆ isAnti()

bool Dependence::isAnti ( ) const

isAnti - Returns true if this is an anti dependence.

Definition at line 248 of file DependenceAnalysis.cpp.

References Dst, llvm::Instruction::mayReadFromMemory(), llvm::Instruction::mayWriteToMemory(), and Src.

Referenced by dump(), and isOrdered().

◆ isConfused()

virtual bool llvm::Dependence::isConfused ( ) const

inlinevirtual

isConfused - Returns true if this dependence is confused (the compiler understands nothing and makes worst-case assumptions).

Reimplemented in llvm::FullDependence.

Definition at line 145 of file DependenceAnalysis.h.

Referenced by dump().

◆ isConsistent()

virtual bool llvm::Dependence::isConsistent ( ) const

inlinevirtual

isConsistent - Returns true if this dependence is consistent (occurs every time the source and destination are executed).

Reimplemented in llvm::FullDependence.

Definition at line 149 of file DependenceAnalysis.h.

Referenced by dump().

◆ isDirectionNegative()

virtual bool llvm::Dependence::isDirectionNegative ( ) const

inlinevirtual

Check if the direction vector is negative.

A negative direction vector means Src and Dst are reversed in the actual program.

Reimplemented in llvm::FullDependence.

Definition at line 165 of file DependenceAnalysis.h.

◆ isFlow()

bool Dependence::isFlow ( ) const

isFlow - Returns true if this is a flow (aka true) dependence.

Definition at line 242 of file DependenceAnalysis.cpp.

References Dst, llvm::Instruction::mayReadFromMemory(), llvm::Instruction::mayWriteToMemory(), and Src.

Referenced by dump(), and isOrdered().

◆ isInput()

bool Dependence::isInput ( ) const

isInput - Returns true if this is an input dependence.

Definition at line 230 of file DependenceAnalysis.cpp.

References Dst, llvm::Instruction::mayReadFromMemory(), and Src.

Referenced by dump(), and isUnordered().

◆ isLoopIndependent()

virtual bool llvm::Dependence::isLoopIndependent ( ) const

inlinevirtual

isLoopIndependent - Returns true if this is a loop-independent dependence.

Reimplemented in llvm::FullDependence.

Definition at line 140 of file DependenceAnalysis.h.

Referenced by dump().

◆ isOrdered()

bool llvm::Dependence::isOrdered ( ) const

inline

isOrdered - Returns true if dependence is Output, Flow, or Anti

Definition at line 132 of file DependenceAnalysis.h.

References isAnti(), isFlow(), and isOutput().

◆ isOutput()

bool Dependence::isOutput ( ) const

isOutput - Returns true if this is an output dependence.

Definition at line 236 of file DependenceAnalysis.cpp.

References Dst, llvm::Instruction::mayWriteToMemory(), and Src.

Referenced by dump(), and isOrdered().

◆ isPeelFirst()

virtual bool llvm::Dependence::isPeelFirst ( unsigned Level ) const

inlinevirtual

isPeelFirst - Returns true if peeling the first iteration from this loop will break this dependence.

Reimplemented in llvm::FullDependence.

Definition at line 175 of file DependenceAnalysis.h.

Referenced by dump().

◆ isPeelLast()

virtual bool llvm::Dependence::isPeelLast ( unsigned Level ) const

inlinevirtual

isPeelLast - Returns true if peeling the last iteration from this loop will break this dependence.

Reimplemented in llvm::FullDependence.

Definition at line 179 of file DependenceAnalysis.h.

Referenced by dump().

◆ isScalar()

bool Dependence::isScalar ( unsigned Level ) const

virtual

isScalar - Returns true if a particular level is scalar; that is, if no subscript in the source or destination mention the induction variable associated with the loop at this level.

Reimplemented in llvm::FullDependence.

Definition at line 257 of file DependenceAnalysis.cpp.

Referenced by dump().

◆ isSplitable()

virtual bool llvm::Dependence::isSplitable ( unsigned Level ) const

inlinevirtual

isSplitable - Returns true if splitting this loop will break the dependence.

Reimplemented in llvm::FullDependence.

Definition at line 183 of file DependenceAnalysis.h.

Referenced by dump(), and llvm::DependenceInfo::getSplitIteration().

◆ isUnordered()

bool llvm::Dependence::isUnordered ( ) const

inline

isUnordered - Returns true if dependence is Input

Definition at line 136 of file DependenceAnalysis.h.

References isInput().

◆ normalize()

virtual bool llvm::Dependence::normalize ( ScalarEvolution * SE )

inlinevirtual

If the direction vector is negative, normalize the direction vector to make it non-negative.

Normalization is done by reversing Src and Dst, plus reversing the dependence directions and distances in the vector.

Reimplemented in llvm::FullDependence.

Definition at line 171 of file DependenceAnalysis.h.

◆ operator=()

Dependence & llvm::Dependence::operator= ( Dependence && )

protecteddefault

◆ setNextPredecessor()

void llvm::Dependence::setNextPredecessor ( const Dependence * pred )

inline

setNextPredecessor - Sets the value of the NextPredecessor field.

Definition at line 200 of file DependenceAnalysis.h.

References pred.

◆ setNextSuccessor()

void llvm::Dependence::setNextSuccessor ( const Dependence * succ )

inline

setNextSuccessor - Sets the value of the NextSuccessor field.

Definition at line 204 of file DependenceAnalysis.h.

Friends And Related Function Documentation

◆ DependenceInfo

friend class DependenceInfo

friend

Definition at line 215 of file DependenceAnalysis.h.

Member Data Documentation

◆ Dst

Instruction * llvm::Dependence::Dst

protected

Definition at line 211 of file DependenceAnalysis.h.

Referenced by getDst(), isAnti(), isFlow(), isInput(), isOutput(), and llvm::FullDependence::normalize().

◆ Src

Instruction* llvm::Dependence::Src

protected

Definition at line 211 of file DependenceAnalysis.h.

Referenced by getSrc(), isAnti(), isFlow(), isInput(), isOutput(), and llvm::FullDependence::normalize().

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

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

Classes

Public Member Functions

Protected Member Functions

Protected Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ Dependence() [1/2]

◆ Dependence() [2/2]

◆ ~Dependence()

Member Function Documentation

◆ dump()

◆ getDirection()

◆ getDistance()

◆ getDst()

◆ getLevels()

◆ getNextPredecessor()

◆ getNextSuccessor()

◆ getSrc()

◆ isAnti()

◆ isConfused()

◆ isConsistent()

◆ isDirectionNegative()

◆ isFlow()

◆ isInput()

◆ isLoopIndependent()

◆ isOrdered()

◆ isOutput()

◆ isPeelFirst()

◆ isPeelLast()

◆ isScalar()

◆ isSplitable()

◆ isUnordered()

◆ normalize()

◆ operator=()

◆ setNextPredecessor()

◆ setNextSuccessor()

Friends And Related Function Documentation

◆ DependenceInfo

Member Data Documentation

◆ Dst

◆ Src