[libclc] [libclc] Add LIBCLC_GENERATE_BITCODE option to skip bitcode/SPIR-V generation (PR #214150)

[Wenju He via cfe-commits]

wenju-he wrote:

> Is it worth being defensive here? My intention was that in the future we could experiment with using either version. I do this for the libc libraries as well, shipping both a `.a` and a `.bc` that can be used in different circumstances. Now, the most expensive part of compiling libclc is the final merged optimization pass, is that what you're trying to avoid?

Thanks.

There is no push or jira on this. I just find bitcode now has no use in our PISA downstream repo, so I'm considering this might be redundant. But our downstream do have libclc bitcode use for other compilation paths, including SYCL/openmp.

So it might not be worth to complicate the cmake files for now. Close this PR.


https://github.com/llvm/llvm-project/pull/214150