Signed overflow optimization hazards in the kernel

However, the Linux kernel's code can be legitimately used in any GPLv2 project, including those that might run on systems with non-twos-complement signed integer arithmetic. This sharing of code among compatibly licensed projects is a very good thing, in my view.

Which means in this case, where there is a solution that meets the C standard, and which loses nothing by doing so (at least on x86 and Power), it only makes sense to use that C-standard solution.