sdfg::transformations::LoopRotate Class Reference

Loop rotation transformation to convert negative stride to positive stride. More...

#include <sdfg/transformations/loop_rotate.h>

Inheritance diagram for sdfg::transformations::LoopRotate:

Public Member Functions
	LoopRotate (structured_control_flow::StructuredLoop &loop)
	Construct a LoopRotate transformation.
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 &	rotated_container_name () const
	Get the name of the container holding the rotated (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 LoopRotate	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 rotation transformation to convert negative stride to positive stride.

This transformation reverses the iteration direction of a loop with negative stride.

Original loop (negative stride): for (i = init; bound < i; i -= 1) // or equivalently: i > bound body(i)

After LoopRotate: for (i = bound+1; i < init+1; i += 1) body(init + bound + 1 - i) // Transformed index

Example: // Original: i = 10, 9, 8, ..., 1 (while i > 0) for (i = 10; 0 < i; i–) A[i] = ...

// After rotation: i' = 1, 2, 3, ..., 10 for (i = 1; i < 11; i++) A[11 - i] = ... // 11-1=10, 11-2=9, ..., 11-10=1

Prerequisites:

• Loop must have stride == -1
• Loop condition must have extractable lower bound (form: bound < indvar)

Benefits:

• Enables further transformations that require positive stride
• Normalizes loops for analysis
• Works with both For and Map loops

Note

After applying this transformation, you should run SymbolPropagation to propagate the rotated index expression into the loop body.

Constructor & Destructor Documentation

LoopRotate()

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

explicit

Construct a LoopRotate transformation.

Parameters

loop	The loop to rotate (must have negative stride)

Member Function Documentation

apply()

virtual void sdfg::transformations::LoopRotate::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::LoopRotate::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()

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

static

name()

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

overridevirtual

Get the name of this transformation.

Returns

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

Implements sdfg::transformations::Transformation.

rotated_container_name()

const std::string & sdfg::transformations::LoopRotate::rotated_container_name ( ) const

inline

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

Returns

The container name, or empty string if not yet applied

to_json()

virtual void sdfg::transformations::LoopRotate::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_rotate.h