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".
Zig also has a similar approach.
It is best to have ergonomic checked version of arithmetic functions and always use them when possible, and use the debug only checked versions on other places.
Performance of checked arithmetic will basically never matter around things like allocation in my experience
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 It is ancient, but I don’t see a reason why it would have become outdated.
