[all-commits] [llvm/llvm-project] a8f386: [mlir][tensor] Fix bug in `tensor.extract(tensor.f...

[Rafael Ubal via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a8f3860bcb644d724275f51e7db7b291c7a3f4df
      https://github.com/llvm/llvm-project/commit/a8f3860bcb644d724275f51e7db7b291c7a3f4df
  Author: Rafael Ubal <rubal at mathworks.com>
  Date:   2023-12-12 (Tue, 12 Dec 2023)

  Changed paths:
    M mlir/lib/Dialect/Tensor/IR/TensorOps.cpp
    M mlir/test/Dialect/Tensor/canonicalize.mlir

  Log Message:
  -----------
  [mlir][tensor] Fix bug in `tensor.extract(tensor.from_elements)` folder (#75109)

The folder for `tensor.extract` is not operating correctly when it is
consuming the result of a `tensor.from_elements` operation.

The existing unit test named `@extract_from_tensor.from_elements_3d` in
`mlir/test/Dialect/Tensor/canonicalize.mlir` seems an attempt to stress
this code. However, this unit tests creates a `tensor.from_elements` op
exclusively from constants, which gets folded away into a single
constant tensor. Therefore, the buggy code was never executed in unit
tests.

I have added a new unit test named
`@extract_from_tensor.from_elements_variable_3d` that makes sure the
`tensor.from_elements` op is not folded away by having its input
operands come directly from function arguments. The original folder code
would have made this test fail.

This bug was notably affecting the lowering of the `tosa.pad` op in the
`tosa-to-tensor` pass, where the generated code is likely to contain a
`tensor.from_elements` + `tensor.extract` op sequence.