Comment by astrange
3 years ago
The signed integer overflow rule is extremely important for common optimizations, mostly related to loops like knowing if they're finite or rewriting their index directions.
The way to start getting rid of it would be to add for...in... loops or something where the loop index can be a custom no-overflow type.
And "defining" it is a lame approach to safety. If you make it wraparound, you now have silent wraparounds that can't be found by static analysis. You want unintended overflows to trap, not just be defined.
> And "defining" it is a lame approach to safety. If you make it wraparound, you now have silent wraparounds that can't be found by static analysis. You want unintended overflows to trap, not just be defined.
Yes. But even the lame approach is better than UB, because it doesn't bring the whole program down.
I've been wondering if I should mention that using int for an index is a bad idea because the standard only guarantees it's 16 bits. You should use size_t instead. And in C size_t is unsigned.
My take is all of the low hanging fruit optimizations that the standard enables has been picked a long time ago. Everything left is problematic.