[SVE] Support splitting by vscale in `tir::split` and `te::split` (#16862)

This commit adds support for splitting via the compile-time unknown
constant `vscale`. Two main changes are introduced; they are described
below.

The split scheduling primitive has a new parameter disable_predication
that allows the user to avoid introducing a block-level predicate when
splitting with a factor of `vscale`. This feature is useful when schedule
writers know that the loop they're splitting is a factor of the scalable
vector length for their target. Otherwise, a predicate must be introduced
due to the nature of `vscale`.

CanProve has been extended to prove expressions that use multiple
instances of `vscale`. Known possible scalar values of the `vscale`
intrinsic are iterated over and substituted into the expression. If
the expression holds true for each possible value, we can conclude the
expression true. Currently only support for an SVE target has been
added, but it is possible to extend to other targets as/when needed. If
the analyzer becomes more powerful in the future and is able to deal
with multiple instances of a symbolic value in an expression, this
feature can be removed.

---------

Co-authored-by: Elen Kalda <elen.kalda@arm.com>
Co-authored-by: Neil Hickey <neil.hickey@arm.com>
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tree: 9d3be3fe9fd008abcc6b3b2b44da5ee2d24ee66a
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  11. golang/
  12. include/
  13. jvm/
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  17. src/
  18. tests/
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  28. conftest.py
  29. CONTRIBUTORS.md
  30. KEYS
  31. LICENSE
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  33. mypy.ini
  34. NEWS.md
  35. NOTICE
  36. pyproject.toml
  37. README.md
  38. version.py
README.md

Open Deep Learning Compiler Stack

Documentation | Contributors | Community | Release Notes

Build Status WinMacBuild

Apache TVM is a compiler stack for deep learning systems. It is designed to close the gap between the productivity-focused deep learning frameworks, and the performance- and efficiency-focused hardware backends. TVM works with deep learning frameworks to provide end to end compilation to different backends.

License

TVM is licensed under the Apache-2.0 license.

Getting Started

Check out the TVM Documentation site for installation instructions, tutorials, examples, and more. The Getting Started with TVM tutorial is a great place to start.

Contribute to TVM

TVM adopts apache committer model, we aim to create an open source project that is maintained and owned by the community. Check out the Contributor Guide.

Acknowledgement

We learned a lot from the following projects when building TVM.

  • Halide: Part of TVM's TIR and arithmetic simplification module originates from Halide. We also learned and adapted some part of lowering pipeline from Halide.
  • Loopy: use of integer set analysis and its loop transformation primitives.
  • Theano: the design inspiration of symbolic scan operator for recurrence.