jlm::llvm::DeadNodeElimination Class Reference

Dead Node Elimination Optimization. More...

#include <DeadNodeElimination.hpp>

Inheritance diagram for jlm::llvm::DeadNodeElimination:

Collaboration diagram for jlm::llvm::DeadNodeElimination:

Classes
class	Context
	Dead Node Elimination context class. More...
class	Statistics
	Dead Node Elimination statistics class. More...

Public Member Functions
	~DeadNodeElimination () noexcept override
	DeadNodeElimination ()
	DeadNodeElimination (const DeadNodeElimination &)=delete
	DeadNodeElimination (DeadNodeElimination &&)=delete
DeadNodeElimination &	operator= (const DeadNodeElimination &)=delete
DeadNodeElimination &	operator= (DeadNodeElimination &&)=delete
void	run (rvsdg::Region &region)
void	Run (rvsdg::RvsdgModule &module, util::StatisticsCollector &statisticsCollector) override
	Perform RVSDG transformation. More...
Public Member Functions inherited from jlm::rvsdg::Transformation
virtual	~Transformation () noexcept
	Transformation (std::string_view Name)
const std::string_view &	GetName () const noexcept
void	Run (RvsdgModule &module)
	Perform RVSDG transformation. More...

Private Member Functions
void	markRegion (const rvsdg::Region &region)
void	markOutput (const rvsdg::Output &output)
void	sweepRvsdg (rvsdg::Graph &rvsdg) const
void	sweepRegion (rvsdg::Region &region) const
void	sweepStructuralNode (rvsdg::StructuralNode &node) const
void	sweepGamma (rvsdg::GammaNode &gammaNode) const
void	sweepTheta (rvsdg::ThetaNode &thetaNode) const
void	sweepLambda (rvsdg::LambdaNode &lambdaNode) const
void	sweepPhi (rvsdg::PhiNode &phiNode) const

Static Private Member Functions
static void	sweepDelta (rvsdg::DeltaNode &deltaNode)
static void	removeNode (rvsdg::Node &node)

Private Attributes
std::unique_ptr< Context >	Context_ {}

Detailed Description

Dead Node Elimination Optimization.

Dead Node Elimination removes all nodes that do not contribute to the result of a computation. A node is considered dead if all its outputs are dead, and an output is considered dead if it has no users or all its users are already dead. An input (and therefore an outputs' user) is considered dead if the corresponding node is dead. We call all nodes, inputs, and outputs that are not dead alive.

The Dead Node Elimination optimization consists of two phases: mark and sweep. The mark phase traverses the RVSDG and marks all nodes, inputs, and outputs that it finds as alive, while the sweep phase removes then all nodes, inputs, and outputs that were not discovered by the mark phase, i.e., all dead nodes, inputs, and outputs.

Please see TestDeadNodeElimination.cpp for Dead Node Elimination examples.

Definition at line 43 of file DeadNodeElimination.hpp.

Constructor & Destructor Documentation

~DeadNodeElimination()

jlm::llvm::DeadNodeElimination::~DeadNodeElimination ( )

overridedefaultnoexcept

DeadNodeElimination() [1/3]

jlm::llvm::DeadNodeElimination::DeadNodeElimination

(

)

Definition at line 137 of file DeadNodeElimination.cpp.

DeadNodeElimination() [2/3]

jlm::llvm::DeadNodeElimination::DeadNodeElimination ( const DeadNodeElimination &  )

delete

DeadNodeElimination() [3/3]

jlm::llvm::DeadNodeElimination::DeadNodeElimination ( DeadNodeElimination &&  )

delete

Member Function Documentation

markOutput()

void jlm::llvm::DeadNodeElimination::markOutput ( const rvsdg::Output &  output )

private

Definition at line 194 of file DeadNodeElimination.cpp.

markRegion()

void jlm::llvm::DeadNodeElimination::markRegion ( const rvsdg::Region &  region )

private

Definition at line 185 of file DeadNodeElimination.cpp.

operator=() [1/2]

DeadNodeElimination& jlm::llvm::DeadNodeElimination::operator= ( const DeadNodeElimination &  )

delete

operator=() [2/2]

DeadNodeElimination& jlm::llvm::DeadNodeElimination::operator= ( DeadNodeElimination &&  )

delete

removeNode()

void jlm::llvm::DeadNodeElimination::removeNode ( rvsdg::Node &  node )

staticprivate

Definition at line 531 of file DeadNodeElimination.cpp.

run()

void jlm::llvm::DeadNodeElimination::run

(

rvsdg::Region &

region

)

Definition at line 142 of file DeadNodeElimination.cpp.

Run()

void jlm::llvm::DeadNodeElimination::Run ( rvsdg::RvsdgModule &  module, util::StatisticsCollector &  statisticsCollector  )

overridevirtual

Perform RVSDG transformation.

Note

This method is expected to be called multiple times. An implementation is required to reset the objects' internal state to ensure correct behavior after every invocation.

Parameters

module	RVSDG module the transformation is performed on.
statisticsCollector	Statistics collector for collecting transformation statistics.

Implements jlm::rvsdg::Transformation.

Definition at line 154 of file DeadNodeElimination.cpp.

sweepDelta()

void jlm::llvm::DeadNodeElimination::sweepDelta ( rvsdg::DeltaNode &  deltaNode )

staticprivate

Definition at line 522 of file DeadNodeElimination.cpp.

sweepGamma()

void jlm::llvm::DeadNodeElimination::sweepGamma ( rvsdg::GammaNode &  gammaNode ) const

private

Definition at line 421 of file DeadNodeElimination.cpp.

sweepLambda()

void jlm::llvm::DeadNodeElimination::sweepLambda ( rvsdg::LambdaNode &  lambdaNode ) const

private

Definition at line 484 of file DeadNodeElimination.cpp.

sweepPhi()

void jlm::llvm::DeadNodeElimination::sweepPhi ( rvsdg::PhiNode &  phiNode ) const

private

Definition at line 491 of file DeadNodeElimination.cpp.

sweepRegion()

void jlm::llvm::DeadNodeElimination::sweepRegion ( rvsdg::Region &  region ) const

private

Definition at line 354 of file DeadNodeElimination.cpp.

sweepRvsdg()

void jlm::llvm::DeadNodeElimination::sweepRvsdg ( rvsdg::Graph &  rvsdg ) const

private

Definition at line 336 of file DeadNodeElimination.cpp.

sweepStructuralNode()

void jlm::llvm::DeadNodeElimination::sweepStructuralNode ( rvsdg::StructuralNode &  node ) const

private

Definition at line 390 of file DeadNodeElimination.cpp.

sweepTheta()

void jlm::llvm::DeadNodeElimination::sweepTheta ( rvsdg::ThetaNode &  thetaNode ) const

private

Definition at line 457 of file DeadNodeElimination.cpp.

Member Data Documentation

Context_

std::unique_ptr<Context> jlm::llvm::DeadNodeElimination::Context_ {}

private

Definition at line 103 of file DeadNodeElimination.hpp.

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

• jlm/llvm/opt/DeadNodeElimination.hpp
• jlm/llvm/opt/DeadNodeElimination.cpp