[clang] Bulk port 64-bit x86 builtins to TableGen (PR #121043)

[Phoebe Wang via cfe-commits]

phoebewang wrote:

> So, my preference is to keep this as is, and allow folks familiar with the specific builtins to merge groups together that make logical sense in follow-up PRs. Would that work for folks to at least get us out from using the X-macros?

Agreed! Can you share the script please? We have many internal builtins need to update, it would be great if it can be done by automation.

What's the X-macros mean?

https://github.com/llvm/llvm-project/pull/121043