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

[Pavel Novikov via libcxx-commits]

toughengineer wrote:

No idea. 650% looks ridiculous by any stretch of imagination so something is clearly wrong.

I get results with Clang 22.1.2 on x86-64 Ubuntu 26.04 that are more consistent with macOS 26.5 arm64 results here https://github.com/llvm/llvm-project/pull/210078#issuecomment-5034397079.

Which compiler flags are used for benchmarks?

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