- Definitely cheaper than using Electron I would say
- In Swift (Apple’s C++ successor), the normal operators (`+`, `-`, `*`) trap on overflow for integer types. If you want twos complement wrapping, you can use `&+`, `&-`, and `&*`.
Given that Apple has been making its own CPU cores for years now, I suspect overflowing checking on Apple CPUs is virtually free (aside from code size).
- > Given that Apple has been making its own CPU cores for years now, I suspect overflowing checking on Apple CPUs is virtually free (aside from code size).
Never make guesses based on a particular programming language. In Apple's own C documentation (https://developer.apple.com/documentation/xcode/integer-over...) it is stated that "Overflows result in undefined behavior." and enabling wrapping behaviour "may adversely impact performance", indicating that overflow detection is in fact not "virtually free".
- Code size (and branch table entries) are not free, of course. The other thing to note is that trapping operators often need to trap precisely which can lead to missed optimizations.
- One example of such an optimization is that overflow checking can prevent vectorization of code.
See for example this post: https://lemire.me/blog/2016/12/06/dont-assume-that-safety-co.... It is ancient, but I don’t see a reason why it would have become outdated.
- 2014 (probably? Or 2008. Old and no date) Previously (166 points, 2014, 107 comments) https://news.ycombinator.com/item?id=8765714
- Resubmitting it seems timely, given recent Linux kernel news (e.g. https://lwn.net/Articles/1065889/).
- The archive says "12/14", so 2014 seems about right.
- [flagged]
