Fix BF16 detection in x86_64 ukernel cmake

[vient]

_mm512_cvtneps_pbh was used incorrectly in IREE_UK_BUILD_X86_64_AVX512_BF16 cmake test, so it always failed.

[vient]

Don't know if it affects anything. Surely not in runtime? I just tried to build IREE for the first time and noticed Performing Test IREE_UK_BUILD_X86_64_AVX512_BF16 - Failed in cmake output.

https://godbolt.org/z/WzEsYv1hK just in case

[bjacob]

Thanks! I had been wondering why it was failing 🤦 it does not affect real functionality, only tests. Real functionality depends on the bitcode build of ukernels which has these features unconditional.

[vient]

So, do I need to do anything else here, or this pull request just got lost? "2 expected checks" don't know what to do about these.

[ScottTodd]

So, do I need to do anything else here, or this pull request just got lost? "2 expected checks" don't know what to do about these.

Thanks for the ping.

Regular contributors usually have write access and can merge their own PRs. We sometimes need a reminder when that isn't the case and we'll merge for you: https://iree.dev/developers/general/contributing/#merging-approved-changes.

As for the expected checks, those workflows were added recently and the commit this was based at predates them. If you sync your PR branch (e.g. by rebasing onto main or merging main into your branch), those checks should run. In this case though, I'm comfortable just bypassing the branch protection / required checks since the tests that ran when this was sent should be sufficient.