On 01/30/2011 10:20 AM, Ralf Wildenhues wrote: >> +verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2); > This doesn't make sense to me. If long_int has the same width as int, > then the right hand side overflows thus invokes undefined behavior.
No, because this is a constant expression. The C Standard requires compilers to diagnose constraint violations, and one of the constraints is that constant expressions must not overflow. So a diagnostic is required here, which is all that we can ask from "verify". Would it be clearer if we did this instead? verify (long_int_is_wide_enough, INT_MAX * (long_int) 2); This would be just as good from the technical point of view.
