[clang] [X86] Fix Wrong type in builtin prototype (PR #182242)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman requested changes to this pull request.

Is this a case where it makes more sense to make tablegen smarter about vector types (so this kind of mistake is caught and we don't decompose to less type information with `void *`) than to switch to `void *`?

Marking as requesting changes given there's quite a few questions around this PR at the moment.

https://github.com/llvm/llvm-project/pull/182242