Implement non-unit stride dense vectorization (difficult starter)

[aartbik]

Bugzilla Link	52318
Version	unspecified
OS	Linux
CC	@joker-eph

Extended Description

Implement strided load/stores on dense arrays, so that vectorization does not need to be disabled when the access pattern is non-contiguous for the dense data structures.

Start by looking at denseUnitStrides() in https://github.com/llvm/llvm-project/blob/main/mlir/lib/Dialect/SparseTensor/Transforms/Sparsification.cpp

This will require tensor loads and stores that have become non-unit stride to compute the proper strides and use this during vectorization.

This is a non-trivial starter, and requires adding vector dialect support first (for the non-unit stride load and stores) and then very careful engineering within the sparse compiler codegen).

[aartbik]

assigned to @aartbik

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Assign the issue to you.
2. Fix the issue locally.
3. Run the test suite locally.
   3.1) Remember that the subdirectories under test/ create fine-grained testing targets, so you can
   e.g. use make check-clang-ast to only run Clang's AST tests.
4. Create a git commit
5. Run git clang-format HEAD~1 to format your changes.
6. Submit the patch to Phabricator.
   6.1) Detailed instructions can be found here

For more instructions on how to submit a patch to LLVM, see our documentation.

If you have any further questions about this issue, don't hesitate to ask via a comment on this Github issue.

@llvm/issue-subscribers-good-first-issue

[brnorris03]

assigned to @aartbik

Is this still something that needs doing, and is anyone working on it?