54
The Little Things: The Missing Performance in std::vector
(codingnest.com)
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 28 Aug 2023
54 points (96.6% liked)
Programming
17314 readers
238 users here now
Welcome to the main community in programming.dev! Feel free to post anything relating to programming here!
Cross posting is strongly encouraged in the instance. If you feel your post or another person's post makes sense in another community cross post into it.
Hope you enjoy the instance!
Rules
Rules
- Follow the programming.dev instance rules
- Keep content related to programming in some way
- If you're posting long videos try to add in some form of tldr for those who don't want to watch videos
Wormhole
Follow the wormhole through a path of communities !webdev@programming.dev
founded 1 year ago
MODERATORS
Couldn't this be solved by having
push_backbeing an inline function (or at least the check on capacity being inlined and the rest of the non-trivial part being in a sub non-inline function)?I don't know about C++, but in Rust the push is inline, and still doesn't always optimize checks away due to an annoying edge case: integer overflow. Reserving (old_len + new_len) could give you a smaller buffer than new_len. The optimizer sees it and is pedantic about it.
In C++ integer overflow is UB so this edge case cannot exist
Only signed overflow. size_t is unsigned.
That's totally right but I thought you were talking about signed numbers since you said “integer overflow”. I forgot that
lenis usually unsigned in C++.