[mlir][linalg] Fix scalable vectorisation of tensor.extract (#100325)

This PR fixes one very specific aspect of vectorising `tensor.extract`
Ops when targeting scalable vectors. Namely, it makes sure that the
scalable flag is correctly propagated when creating
`vector::ShapeCastOp`.

BEFORE:
```mlir
vector.shape_cast %idx_vec : vector<1x1x[4]xindex> to vector<4xindex>
```

AFTER:
```mlir
vector.shape_cast %idx_vec : vector<1x1x[4]xindex> to vector<[4]xindex>
```

This particular ShapeCastOp is created when generating an index for
`vector.transfer_read` operations. Strictly speaking, casting is not
really required. However, it makes the subsequent address calculation
much simpler (*).

The following test is updated to demonstrate the use of
`vector.shape_cast` by the vectoriser:
*
@masked_static_vectorize_nd_tensor_extract_with_affine_apply_contiguous

Similar test with scalable vectors is also added.

(*) At this point in the vectoriser it is known
that all leading dims in the index vector are "1").

0 files changed, 0 insertions, 0 deletions