Better handling of integer wraparound in the kernel

I wonder if it would be possible to get an operator into C that would take an expression without side effects and return true if it would overflow and false otherwise. Having it be an operator (like typeof) would mean that (from the point of view of C and the compiler) you're not evaluating the expression, so it's not UB, and the compiler would be able to optimize the case where, if the operator returns false, you do evaluate the expression, and also makes it easier to optimize overflow checks in general (since the optimal assembly doesn't actually do the inequality test the programmer wrote, but looks at the overflow flag after the addition).

The program would still have to duplicate the expression, but at least it would be easy to have a warning if they don't match.