[llvm] [LangRef] No target-specific size limit for atomics (PR #136864)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

So it seems like there is still a limit, at least on some targets?

Maybe it's sufficient to just note that most targets support arbitrary widths using a lock-based fallback.

https://github.com/llvm/llvm-project/pull/136864