[llvm-branch-commits] [libcxx] [libc++][format][3/7] Improves std::format performance. (PR #101817)

[Louis Dionne via llvm-branch-commits]

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

As discussed, I think we should behave more like `std::vector` and not assume that elements between `[size(), capacity())` are already initialized. IMO this is a simpler mental model that is consistent with `std::vector` and I don't think we leave anything on the table by doing that.

https://github.com/llvm/llvm-project/pull/101817