[clang] [llvm] [Clang] Add `__builtin_stack_address` (PR #148281)

[Nikita Popov via llvm-commits]

nikic wrote:

> > You'd probably want to define STACKADDRESS with a default expansion to STACKSAVE, plus custom legalization on SPARC. There should be no direct triple checks.
> 
> Thx for the pointer @nikic , does this revision address your comment properly?

Yes, thank you.

https://github.com/llvm/llvm-project/pull/148281