[clang] [Clang] Demote always_inline error to warning for mismatching SME attrs (PR #100740)

[Sander de Smalen via cfe-commits]

sdesmalen-arm wrote:

> At a glance, this seems like a good use case for a warning + `DefaultError`?

I'd rather not make that change, because in practice it will be unlikely that inlining will result in changes to runtime behaviour. We'd rather not burden the users with explicit errors for something that may be fine, as it's more a limitation of Clang that it has to emit this message in the first place. Separate to that, it might not be directly clear to users that the error can be demoted into a warning.

Thanks for the suggestion though!

https://github.com/llvm/llvm-project/pull/100740