[Encoding] Add an optional bcast_map attribute to EncodingAttr. (#18032)

This adds a new optional field to encodings called `bcast_map`. When we
set encodings, we want to set encodings on the inputs to broadcasting
operations, since it is less data to pack. This `bcast_map` is a step
towards being able to do this, since it is needed in order to know which
dimensions of the tensor correspond to which dimensions of the packed
layout.

The new field is an affine map that encodes which dimensions of the
encoded tensor map to which dimensions in the corresponding operand of
the data tiled op. For example, if the LHS of a matmul is broadcasted
along the batch dimension, and we set encoding on the input to the
broadcast:
```mlir
#map = affine_map<(d0, d1, d2) -> (d1, d2)>
#map1 = affine_map<(d0, d1, d2) -> (d0, d1, d2)>
%se = iree_encoding.set_encoding %lhs : tensor<4x16xf32> -> tensor<4x16xf32, ... bcast_map = #map
%bcast = linalg.broadcast ins(%lhs ... outs(%e : tensor<2x4x16xf32, ... bcast_map = #map1 ... dimensions = [0]
```
The result of the broadcast, which will be consumed by the matmul, has
an identity broadcast map, and the input to the broadcast has a
broadcasted affine map. The `#map` says that the dimensions of `%se`
correspond to `d1` and `d2` in the LHS of the matmul that consumes
`%bcast`.

In cases where we transpose narrow N matmuls, the `bcast_map` remains
the same. Handling this properly is left as a TODO, to be fixed when
more pieces land, and we can more properly test transposed narrow N
matmuls. This is okay for now, since the `bcast_map` is not actually
used anywhere yet.

Signed-off-by: hanhanW <hanhan0912@gmail.com>
Co-authored-by: hanhanW <hanhan0912@gmail.com>
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  5. experimental/
  6. integrations/
  7. lib/
  8. llvm-external-projects/
  9. runtime/
  10. samples/
  11. tests/
  12. third_party/
  13. tools/
  14. .bazel_to_cmake.cfg.py
  15. .bazelignore
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  26. AUTHORS
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  28. CITATION.cff
  29. CMakeLists.txt
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  31. CONTRIBUTING.md
  32. LICENSE
  33. MAINTAINERS.md
  34. README.md
  35. RELEASING.md
  36. 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 IREE Discord 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

Community meeting recordings: IREE YouTube channel

  • 2021-06-09: IREE Runtime Design Tech Talk (recording and slides)
  • 2020-08-20: IREE CodeGen: MLIR Open Design Meeting Presentation (recording and slides)
  • 2020-03-18: Interactive HAL IR Walkthrough (recording)
  • 2020-01-31: End-to-end MLIR Workflow in IREE: MLIR Open Design Meeting Presentation (recording and slides)

License

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