docs/ReleaseNotes.md - llvm-project/mlir - Git at Google

 # MLIR Release Notes

 This document tries to provide some context about MLIR important changes in the
 context of LLVM releases. It is updated on a best effort basis.

 At the moment the MLIR community does not qualify the LLVM release branch
 specifically, it is a snapshot of the MLIR development at the time of the release.

 [TOC]

 ## LLVM 20

 All the MLIR runners other than `mlir-cpu-runner` have been removed, as their functionality has been merged into it, and it has been renamed to `mlir-runner`.

 ## LLVM 18

 ### Properties: beyond attributes

 See LLVM 17 notes below. The Dialect option `let usePropertiesForAttributes = 1;` is
 now the default. You can set it to 0 to revert to the previous behavior. This will be
 removed in LLVM 19.

 ## LLVM 17

 See also the [deprecations and refactoring](https://mlir.llvm.org/deprecation/) doc.

 ### Bytecode

 MLIR now support a [bytecode serialization](https://mlir.llvm.org/docs/BytecodeFormat/)
 with versionning compatibility allowing 2 ways compatibility scheme, and lazy-loading
 capabilities.

 ### Properties: beyond attributes

 This is a new mechanism to implement storage for operations without having to
 use attributes. You can opt-in to use Properties for ODS inherent attributes
 using `let usePropertiesForAttributes = 1;` in your dialect definition (the flag
 will be default in the next release). See
 [slides](https://mlir.llvm.org/OpenMeetings/2023-02-09-Properties.pdf) and
 [recording](https://youtu.be/7ofnlCFzlqg) of the open meeting presentation for
 details.

 ### Action: Tracing and Debugging MLIR-based Compilers

 [Action](https://mlir.llvm.org/docs/ActionTracing/) is a new mechanism to
 encapsulate any transformation of any granularity in a way that can be
 intercepted by the framework for debugging or tracing purposes, including
 skipping a transformation programmatically (think about “compiler fuel” or
 “debug counters” in LLVM). As such, “executing a pass” is an Action, so is “try
 to apply one canonicalization pattern”, or “tile this loop”.

 [slides](https://mlir.llvm.org/OpenMeetings/2023-02-23-Actions.pdf) and
 [recording](https://youtu.be/ayQSyekVa3c) of the open meeting presentation for
 details.

 ### Transform Dialect

 See this [EuroLLVM talk](https://www.youtube.com/watch?v=P4gUj3QtH_Y&t=1s) and
 [the online tutorial](https://mlir.llvm.org/docs/Tutorials/transform/).

 ### Others

 - There is now support for
   "[distinct attributes](https://mlir.llvm.org/docs/Dialects/Builtin/#distinctattribute)".
 - "Resources" (a way to store data outside the MLIR context) and "configuration"
   can now be serialized alongside the IR.
	# MLIR Release Notes

	This document tries to provide some context about MLIR important changes in the
	context of LLVM releases. It is updated on a best effort basis.

	At the moment the MLIR community does not qualify the LLVM release branch
	specifically, it is a snapshot of the MLIR development at the time of the release.

	[TOC]

	## LLVM 20

	All the MLIR runners other than `mlir-cpu-runner` have been removed, as their functionality has been merged into it, and it has been renamed to `mlir-runner`.

	## LLVM 18

	### Properties: beyond attributes

	See LLVM 17 notes below. The Dialect option `let usePropertiesForAttributes = 1;` is
	now the default. You can set it to 0 to revert to the previous behavior. This will be
	removed in LLVM 19.

	## LLVM 17

	See also the [deprecations and refactoring](https://mlir.llvm.org/deprecation/) doc.

	### Bytecode

	MLIR now support a [bytecode serialization](https://mlir.llvm.org/docs/BytecodeFormat/)
	with versionning compatibility allowing 2 ways compatibility scheme, and lazy-loading
	capabilities.

	### Properties: beyond attributes

	This is a new mechanism to implement storage for operations without having to
	use attributes. You can opt-in to use Properties for ODS inherent attributes
	using `let usePropertiesForAttributes = 1;` in your dialect definition (the flag
	will be default in the next release). See
	[slides](https://mlir.llvm.org/OpenMeetings/2023-02-09-Properties.pdf) and
	[recording](https://youtu.be/7ofnlCFzlqg) of the open meeting presentation for
	details.

	### Action: Tracing and Debugging MLIR-based Compilers

	[Action](https://mlir.llvm.org/docs/ActionTracing/) is a new mechanism to
	encapsulate any transformation of any granularity in a way that can be
	intercepted by the framework for debugging or tracing purposes, including
	skipping a transformation programmatically (think about “compiler fuel” or
	“debug counters” in LLVM). As such, “executing a pass” is an Action, so is “try
	to apply one canonicalization pattern”, or “tile this loop”.

	[slides](https://mlir.llvm.org/OpenMeetings/2023-02-23-Actions.pdf) and
	[recording](https://youtu.be/ayQSyekVa3c) of the open meeting presentation for
	details.

	### Transform Dialect

	See this [EuroLLVM talk](https://www.youtube.com/watch?v=P4gUj3QtH_Y&t=1s) and
	[the online tutorial](https://mlir.llvm.org/docs/Tutorials/transform/).

	### Others

	- There is now support for
	"[distinct attributes](https://mlir.llvm.org/docs/Dialects/Builtin/#distinctattribute)".
	- "Resources" (a way to store data outside the MLIR context) and "configuration"
	can now be serialized alongside the IR.