[llvm] [DA] add testcase (PR #116631)

[Sjoerd Meijer via llvm-commits]

https://github.com/sjoerdmeijer approved this pull request.

Adding a test case is always a good thing, so LGTM.

One nit that can be addressed before merging this, some explanations/comments why we expect `output [* * * *]`.

https://github.com/llvm/llvm-project/pull/116631