Nikolas Klauser 38595fb257 [libc++] Remove a few unnecessary branches from basic_string::find (#137266) ...

I've recently looked at the assembly for `basic_string::find()` and
realized that there were a few branches I didn't expect. It turns out
that we check for null before calling `__constexpr_memchr` in some
cases, which the compiler doesn't optimize away. This is a really
uncommon case though, so I'm not convinced it makes a ton of sense to
optimize for that.

The second case is where `__pos >= __sz`. There, we can instead check
`__pos > __sz`, which the optimizer is able to remove if `__pos == 0`,
which is also a quite common case (basic_string::find(CharT), without an
explicit size parameter).

2025-05-07 10:54:34 -04:00

..

char_traits.h

[libc++] Remove a few unnecessary branches from basic_string::find (#137266)

2025-05-07 10:54:34 -04:00

constexpr_c_functions.h

[NFC][libc++] Guard against operator& hijacking. (#128351)

2025-02-27 17:47:34 +01:00

extern_template_lists.h

[libc++][NFC] Refactor string's extern template lists (#137264)

2025-04-25 10:43:13 +02:00