[libcxx-commits] [libcxx] [libc++] fix minor performance issue in `basic_string<C>::append()` (PR #210078)

[Louis Dionne via libcxx-commits]

ldionne wrote:

/libcxx-bot benchmark libcxx/test/benchmarks/containers/string.bench.cpp

https://github.com/llvm/llvm-project/pull/210078