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Integer Overflow Checking Cost danluu.com

tcfhgj2 hours ago

Definitely cheaper than using Electron I would say

mayoff3 hours ago

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).

qayxc37 minutes ago

> 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".

saagarjha34 minutes ago

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.

gnabgib2 days ago

2014 (probably? Or 2008. Old and no date) Previously (166 points, 2014, 107 comments) https://news.ycombinator.com/item?id=8765714

zahlman2 days ago

Resubmitting it seems timely, given recent Linux kernel news (e.g. https://lwn.net/Articles/1065889/).

aw16211074 hours ago

The archive says "12/14", so 2014 seems about right.

ardline4 hours ago

[flagged]

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