[SYCL-MLIR] Start with only the single_task.cpp test case

[whitneywhtsang]

Signed-off-by: Tsang, Whitney [email protected]

[sommerlukas]

Just a few nits in the test-case.

On a more general note, I'm wondering if introducing a sub-directory with new tests is the most efficient way to test SYCL-MLIR.

The repository already contains a rather large set of SYCL tests that we could potentially re-use instead of introducing lots of new tests.
We could create a white-list of tests that should be working on our branch and alter the CMake target (or create a new one) to only run the tests in the white-list using the --filter feature of llvm-lit.

What do you think?

[whitneywhtsang]

The buildbots are failing because sycl-targets suffix with -syclmlir is unhandled by non-sycl-mlir clang.
When testing PR from intel/llvm repo sycl-mlir branch, we will be using the sycl-mlir clang, and the test case should pass with check-sycl-all. (Tested locally for opencl:cpu)

[sommerlukas]

Changes look good, thanks.

IMHO we should just make sure to notify the user that Nvidia and AMD are currently not supported by the SYCL-MLIR-based compilation flow (other than just failing the test).