#include <strengthReduction.h>

Inheritance diagram for P4::DoStrengthReduction:

Public Member Functions
	DoStrengthReduction (bool enableSubConstToAddTransform)

const IR::Node *	postorder (IR::Add *expr) override

const IR::Node *	postorder (IR::ArrayIndex *expr) override

const IR::Node *	postorder (IR::BAnd *expr) override

const IR::Node *	postorder (IR::BOr *expr) override

const IR::Node *	postorder (IR::BXor *expr) override

const IR::Node *	postorder (IR::Cmpl *expr) override

const IR::Node *	postorder (IR::Concat *expr) override

const IR::Node *	postorder (IR::Div *expr) override

const IR::Node *	postorder (IR::Equ *expr) override

const IR::Node *	postorder (IR::LAnd *expr) override

const IR::Node *	postorder (IR::LNot *expr) override

const IR::Node *	postorder (IR::LOr *expr) override

const IR::Node *	postorder (IR::Mask *expr) override

const IR::Node *	postorder (IR::Mod *expr) override

const IR::Node *	postorder (IR::Mul *expr) override

const IR::Node *	postorder (IR::Mux *expr) override

const IR::Node *	postorder (IR::Neq *expr) override

virtual const IR::Node *	postorder (IR::Node *n)

const IR::Node *	postorder (IR::PlusSlice *expr) override

const IR::Node *	postorder (IR::Range *expr) override

const IR::Node *	postorder (IR::Shl *expr) override

const IR::Node *	postorder (IR::Shr *expr) override

const IR::Node *	postorder (IR::Slice *expr) override

const IR::Node *	postorder (IR::Sub *expr) override

const IR::Node *	postorder (IR::UPlus *expr) override

const IR::BlockStatement *	preorder (IR::BlockStatement *bs) override

Public Member Functions inherited from P4::Transform
const IR::Node *	apply_visitor (const IR::Node , const char name=0) override

profile_t	init_apply (const IR::Node *root) override

virtual void	loop_revisit (const IR::Node *)

virtual const IR::Node *	preorder (IR::Node *n)

void	prune ()

virtual void	revisit (const IR::Node , const IR::Node )

void	revisit_visited ()

bool	visit_in_progress (const IR::Node *) const

void	visitAgain () const override

void	visitOnce () const override

Public Member Functions inherited from P4::Visitor
virtual bool	check_global (cstring)

virtual void	clear_globals ()

virtual Visitor *	clone () const

virtual ControlFlowVisitor *	controlFlowVisitor ()

virtual void	end_apply ()

virtual void	end_apply (const IR::Node *root)

virtual void	erase_global (cstring)

template<class T >
const T *	findContext () const

template<class T >
const T *	findContext (const Context *&c) const

template<class T >
const T *	findOrigCtxt () const

template<class T >
const T *	findOrigCtxt (const Context *&c) const

virtual Visitor &	flow_clone ()

virtual void	flow_merge (Visitor &)

virtual bool	flow_merge_closure (Visitor &)

virtual void	flow_merge_global_from (cstring)

virtual void	flow_merge_global_to (cstring)

const Context *	getChildContext () const

int	getChildrenVisited () const

const Context *	getContext () const

int	getContextDepth () const

const IR::Node *	getCurrentNode () const

template<class T >
const T *	getCurrentNode () const

const IR::Node *	getOriginal () const

template<class T >
const T *	getOriginal () const

template<class T >
const T *	getParent () const

virtual bool	has_flow_joins () const

profile_t	init_apply (const IR::Node root, const Context parent_context)

bool	isInContext (const IR::Node *n) const

virtual const char *	name () const

template<class T >
void	parallel_visit (const IR::Vector< T > &v, const char *name, int cidx)

template<class T >
void	parallel_visit (const IR::Vector< T > &v, const char *name=0)

template<class T >
void	parallel_visit (IR::Vector< T > &v, const char *name, int cidx)

template<class T >
void	parallel_visit (IR::Vector< T > &v, const char *name=0)

void	print_context () const

const Visitor &	setCalledBy (const Visitor *visitor)

void	setName (const char *name)

void	visit (const IR::Node &n, const char *name, int cidx)

void	visit (const IR::Node &n, const char *name=0)

void	visit (const IR::Node &n, const char name, int cidx)

void	visit (const IR::Node &n, const char name=0)

void	visit (const IR::Node const &n, const char name, int cidx)

void	visit (const IR::Node const &n, const char name=0)

void	visit (IR::Node &n, const char *name, int cidx)

void	visit (IR::Node &n, const char *name=0)

void	visit (IR::Node &, const char =0, int=0)

template<class T , typename = std::enable_if_t<Util::has_SourceInfo_v<T> && !std::is_pointer_v<T>>, class... Args>
void	warn (const int kind, const char *format, const T &node, Args &&...args)
	The const ref variant of the above.

template<class T , typename = std::enable_if_t<Util::has_SourceInfo_v<T>>, class... Args>
void	warn (const int kind, const char format, const T node, Args &&...args)

bool	warning_enabled (int warning_kind) const

Protected Member Functions
bool	hasSideEffects (const IR::Expression *expr) const

bool	isAllOnes (const IR::Expression *expr) const

bool	isFalse (const IR::Expression *expr) const

bool	isOne (const IR::Expression *expr) const

int	isPowerOf2 (const IR::Expression *expr) const

bool	isTrue (const IR::Expression *expr) const

bool	isZero (const IR::Expression *expr) const

Protected Member Functions inherited from P4::Transform
const IR::Node *	transform_child (const IR::Node *child)

Protected Member Functions inherited from P4::Visitor
virtual void	init_join_flows (const IR::Node *)

virtual bool	join_flows (const IR::Node *)

virtual void	post_join_flows (const IR::Node , const IR::Node )

void	visit_children (const IR::Node *, std::function< void()> fn)

Protected Attributes
bool	enableSubConstToAddTransform = true

Protected Attributes inherited from P4::Transform
bool	forceClone = false

Protected Attributes inherited from P4::Visitor
bool	dontForwardChildrenBeforePreorder = false

bool	joinFlows = false

bool	visitDagOnce = true

Additional Inherited Members
Public Types inherited from P4::Visitor
typedef Visitor_Context	Context

Static Public Member Functions inherited from P4::Visitor
static cstring	demangle (const char *)

static bool	warning_enabled (const Visitor *visitor, int warning_kind)

Public Attributes inherited from P4::Visitor
const Visitor *	called_by = nullptr

cstring	internalName

SplitFlowVisit_base *&	split_link

SplitFlowVisit_base *	split_link_mem = nullptr

Detailed Description

Implements a pass that replaces expensive arithmetic and boolean operations with cheaper ones – i.e., strength reduction

Specifically, it provides:

A collection of helper methods that determine whether a given expression is 0, 1, true, or false, or a power of 2
A visitor that transforms arithmetic and boolean expressions

Precondition: : None

Postcondition

: Ensure that

most arithmetic and boolean expressions are simplified
division and modulus by 0

Member Function Documentation

◆ hasSideEffects()

bool P4::DoStrengthReduction::hasSideEffects ( const IR::Expression * expr ) const

inlineprotected

Used to determine conservatively if an expression has side-effects. If we had a refMap or a typeMap we could use them here.

◆ isAllOnes()

bool P4::DoStrengthReduction::isAllOnes ( const IR::Expression * expr ) const

protected

Returns: true if expr is all ones.

◆ isFalse()

bool P4::DoStrengthReduction::isFalse ( const IR::Expression * expr ) const

protected

Returns: true if expr is the constant false.

◆ isOne()

bool P4::DoStrengthReduction::isOne ( const IR::Expression * expr ) const

protected

Returns: true if expr is the constant 1.

methods

◆ isPowerOf2()

int P4::DoStrengthReduction::isPowerOf2 ( const IR::Expression * expr ) const

protected

Returns: the logarithm (base 2) of expr if it is positive and a power of 2 and -1 otherwise.

◆ isTrue()

bool P4::DoStrengthReduction::isTrue ( const IR::Expression * expr ) const

protected

Returns: true if expr is the constant true.

◆ isZero()

bool P4::DoStrengthReduction::isZero ( const IR::Expression * expr ) const

protected

Returns: true if expr is the constant 0.

◆ postorder() [1/2]

const IR::Node * P4::DoStrengthReduction::postorder ( IR::Cmpl * expr )

override

Methods

◆ postorder() [2/2]

virtual const IR::Node * P4::Transform::postorder ( IR::Node * n )

inlinevirtual

Reimplemented from P4::Transform.

Member Data Documentation

◆ enableSubConstToAddTransform

bool P4::DoStrengthReduction::enableSubConstToAddTransform = true

protected

Enable the subtract constant to add negative constant transform. Replaces a - constant with a + (-constant).

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ hasSideEffects()

◆ isAllOnes()

◆ isFalse()

◆ isOne()

methods

◆ isPowerOf2()

◆ isTrue()

◆ isZero()

◆ postorder() [1/2]

Methods

◆ postorder() [2/2]

Member Data Documentation

◆ enableSubConstToAddTransform