sdfg::transformations::LoopShift Class Reference

Loop shift transformation to change loop initialization value. More...

#include <sdfg/transformations/loop_shift.h>

Inheritance diagram for sdfg::transformations::LoopShift:

Public Member Functions
	LoopShift (structured_control_flow::StructuredLoop &loop)
	Construct a LoopShift transformation to shift loop to start from 0.
	LoopShift (structured_control_flow::StructuredLoop &loop, const symbolic::Expression &offset)
	Construct a LoopShift transformation with a custom offset.
virtual std::string	name () const override
	Get the name of this transformation.
virtual bool	can_be_applied (builder::StructuredSDFGBuilder &builder, analysis::AnalysisManager &analysis_manager) override
	Check if this transformation can be safely applied.
virtual void	apply (builder::StructuredSDFGBuilder &builder, analysis::AnalysisManager &analysis_manager) override
	Apply this transformation to the SDFG.
virtual void	to_json (nlohmann::json &j) const override
	Serialize this transformation to JSON.
const std::string &	shifted_container_name () const
	Get the name of the container holding the shifted (original) value.
Public Member Functions inherited from sdfg::transformations::Transformation
virtual	~Transformation ()=default
virtual void	set_report (PassReportConsumer *report)
	Set the report consumer for transformation feedback.
virtual bool	try_apply (builder::StructuredSDFGBuilder &builder, analysis::AnalysisManager &analysis_manager)
	Attempt to apply the transformation if possible.

Static Public Member Functions
static LoopShift	from_json (builder::StructuredSDFGBuilder &builder, const nlohmann::json &j)

Additional Inherited Members
Protected Attributes inherited from sdfg::transformations::Transformation
PassReportConsumer *	report_ = nullptr

Detailed Description

Loop shift transformation to change loop initialization value.

This transformation shifts a loop's iteration space.

Original loop: for (i = init; i < bound; i += stride) body(i)

After LoopShift(target_init=0): for (i = 0; i < bound - init; i += stride) { __i_orig = i + init; } // Assignment in transition body(__i_orig) // Uses original value via propagation

Usage:

1. Apply LoopShift transformation
2. Run SymbolPropagation pass to propagate the assignment
3. Run DeadCodeElimination to remove the temporary container if unused

Prerequisites:

• Loop must have an integer init value (for condition adjustment)
• Loop body must not be empty

Note

After applying this transformation, you should run SymbolPropagation to propagate the shifted value into the loop body.

Constructor & Destructor Documentation

LoopShift() [1/2]

sdfg::transformations::LoopShift::LoopShift ( structured_control_flow::StructuredLoop & loop )

explicit

Construct a LoopShift transformation to shift loop to start from 0.

Parameters

loop	The loop to shift

LoopShift() [2/2]

sdfg::transformations::LoopShift::LoopShift	(	structured_control_flow::StructuredLoop &	loop,
		const symbolic::Expression &	offset )

Construct a LoopShift transformation with a custom offset.

Parameters

loop	The loop to shift
offset	The offset to apply to the loop's initial value (e.g., if offset = 1, then new_init = old_init - 1)

Member Function Documentation

apply()

virtual void sdfg::transformations::LoopShift::apply ( builder::StructuredSDFGBuilder & builder, analysis::AnalysisManager & analysis_manager )

overridevirtual

Apply this transformation to the SDFG.

Parameters

builder	The SDFG builder
analysis_manager	The analysis manager (may be invalidated)

Implements sdfg::transformations::Transformation.

can_be_applied()

virtual bool sdfg::transformations::LoopShift::can_be_applied ( builder::StructuredSDFGBuilder & builder, analysis::AnalysisManager & analysis_manager )

overridevirtual

Check if this transformation can be safely applied.

Parameters

builder	The SDFG builder
analysis_manager	The analysis manager providing necessary analyses

Returns

true if all preconditions are met

Implements sdfg::transformations::Transformation.

from_json()

LoopShift sdfg::transformations::LoopShift::from_json ( builder::StructuredSDFGBuilder & builder, const nlohmann::json & j )

static

name()

virtual std::string sdfg::transformations::LoopShift::name ( ) const

overridevirtual

Get the name of this transformation.

Returns

The transformation name (e.g., "LoopInterchange")

Implements sdfg::transformations::Transformation.

shifted_container_name()

const std::string & sdfg::transformations::LoopShift::shifted_container_name ( ) const

inline

Get the name of the container holding the shifted (original) value.

Returns

The container name, or empty string if not yet applied

to_json()

virtual void sdfg::transformations::LoopShift::to_json ( nlohmann::json & j ) const

overridevirtual

Serialize this transformation to JSON.

Parameters

j	JSON object to populate with transformation description

Exceptions

std::logic_error

if not implemented

Implements sdfg::transformations::Transformation.

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

• opt/include/sdfg/transformations/loop_shift.h