Vectorization of tensor.extract using contiguous loads
(vector.transfer_read) was introduced in . This patch updates and
refines the existing logic (so that more cases of contiguous can be
identified), as well as adds more tests.
Specifically, contiguous load operations are identified by making sure
- non-trailing indices for tensor.extract are loop invariant (so, e.g., there are no "jumps" from one row to the other between iterations),
- the trailing index for tensor.extract increments by 1 with every loop iteration (so that it's always adjacent elements that are loaded).
This patch introduces:
- isLoopInvariantIdx for step 1., and
- isContiguousLoadIdx for step 2.
These new methods replace:
- isContiguousLoadIdx, and isBasedOnIndexOp.
Both approaches lead to similar end-result (none of the existing tests
required updating). However, with the updated approach, it's much easier
to treat the trailing and non-trailing indices separately and to add
more cases for which contiguous loads can be used.