[clang] [lldb] [llvm] [AArch64][TargetParser] autogen ArchExtKind enum - renaming (PR #90320)

[David Green via llvm-commits]

davemgreen wrote:

@tmatheson-arm reached out and we have a bit of a conversation internally. I do think that there is too much going on in this one pr to be sensible to review, but from what I've looked at my main points I think are:
 - Some AEK names get renamed in ways I would not expect them to, like AEK_FP16 being changed to AEK_FULLFP16. The command-line names or FEAT_ names should probably be what we are aiming for if we are changing them one-way or the other.
 -  Some of the backend features have been renamed in ways that could cause breakages for external users, like +complxnum becoming +fcma. The new name is better, but ideally the old name would continue to work (maybe by adding an alias/extra target feature dependant on the new name? That might not work with negative features).
 - Some of changes do look mechanical and a good change (P1->p1, V2->v2 etc), and if they were separate they would be easy to get in and out of the way of the contentious stuff that remains.
 - The ones that have changed should have release notes.

https://github.com/llvm/llvm-project/pull/90320