Record narrow static M/N sizes in `EncodingAttr` and rationalize MaterializeEncoding for narrow shapes. (#15431)

This changes how we approach narrow matmul tile size selection (in
particular, vecmat/matvec), from "we don't really care that much, so
let's derive narrow tiles from general ones by just truncation", to "we
actually care, at least in specific cases, about freely controlling
narrow matmul tiles independently of the general wide matmul case."

There are 2 immediate needs for this: @dcaballe was doing something
comparable in #15421 to generally unlock better AVX-512 codegen for
`f32` `vecmat`, and I have a specific need for this in #15158 for some
`s16 x u4` quantized `vecmat` case.

The solution proposed here is more general than the one in #15241 in
that it is not only about `vecmat` and `matvec`, it supports any
narrow-M / narrow-N case. Like #15241, it does so by extending
`EncodingAttr` in some way. Unlike #15241, it does so by adding optional
narrow-M / narrow-N integer attributes, instead of extending the `user`
enum.

Along the way, this rationalizes MaterializeEncoding code around
tile-size selection. Narrow tile sizes are now explicitly enumerated,
and the enumeration of tile sizes is now clearly decoupled from the
choosing among the enumerated tile sizes.

Another change made along the way: this changes the tile shape
convention around here from MxKxN to MxNxK, bringing this in line with
the convention in use in ukernels. The motivation for this convention is
that the MxN part here is particularly important as the output tile
shape, so it helps that the MxNxK convention has that as a contiguous
subset.

To avoid useless redundancy as the narrow-N case is almost 100%
symmetrical to the narrow-M case, the enumeration only goes over
narrow-M cases, and the handling of narrow-N is deferred to the choose
function, transposing the problem to derive narrow-N tiles from narrow-M
tiles. For `vecmat`/`matvec`, the symmetry is perfect, as the
accumulator tile is 1D in these cases, there is no difference at all.
For other non-vector narrow cases, there could conceivably be a
difference someday motivating decoupling narrow-N from narrow-M, but
this is sufficiently far-fetched that it's best to left that to be dealt
with then a concrete use case arises, and enjoy the benefit of smaller
code until then.
9 files changed
tree: 35193cb9c83741287203732cbf7fc0695ecd0b7f
  1. .devcontainer/
  2. .github/
  3. build_tools/
  4. compiler/
  5. docs/
  6. experimental/
  7. integrations/
  8. lib/
  9. llvm-external-projects/
  10. runtime/
  11. samples/
  12. tests/
  13. third_party/
  14. tools/
  15. .bazel_to_cmake.cfg.py
  16. .bazelignore
  17. .bazelrc
  18. .bazelversion
  19. .clang-format
  20. .dockerignore
  21. .git-blame-ignore-revs
  22. .gitignore
  23. .gitmodules
  24. .yamllint.yml
  25. AUTHORS
  26. BUILD.bazel
  27. CITATION.cff
  28. CMakeLists.txt
  29. configure_bazel.py
  30. CONTRIBUTING.md
  31. LICENSE
  32. README.md
  33. WORKSPACE
README.md

IREE: Intermediate Representation Execution Environment

IREE (Intermediate Representation Execution Environment, pronounced as “eerie”) is an MLIR-based end-to-end compiler and runtime that lowers Machine Learning (ML) models to a unified IR that scales up to meet the needs of the datacenter and down to satisfy the constraints and special considerations of mobile and edge deployments.

See our website for project details, user guides, and instructions on building from source.

CI Status

Project Status

IREE is still in its early phase. We have settled down on the overarching infrastructure and are actively improving various software components as well as project logistics. It is still quite far from ready for everyday use and is made available without any support at the moment. With that said, we welcome any kind of feedback on any communication channels!

Communication Channels

Related Project Channels

  • MLIR topic within LLVM Discourse: IREE is enabled by and heavily relies on MLIR. IREE sometimes is referred to in certain MLIR discussions. Useful if you are also interested in MLIR evolution.

Architecture Overview

IREE Architecture IREE Architecture

See our website for more information.

Presentations and Talks

License

IREE is licensed under the terms of the Apache 2.0 License with LLVM Exceptions. See LICENSE for more information.