[libcxx-commits] [libcxx] [libc++] Speed up classic locale (PR #70631)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne requested changes to this pull request.

As Nikolas mentioned, this is an ABI break. The speedup is interesting, but we'd need to either find a way to make this not an ABI break, or to only enable the optimization under an ABI flag.

Is there any reason why we're not storing the classic locale pointer you're adding to the `locale` class inside the `__imp` class instead? I think that would allow not breaking the ABI, since that's a pimpl idiom.

https://github.com/llvm/llvm-project/pull/70631