bug#8545: issues with recent doprnt-related changes

[Paul Eggert]

On 05/01/11 16:59, Richard Stallman wrote:
> This would break many constructions intended to test whether an
> operation did overflow.  Is there any reliable way to test for that?

Yes.  For example:

   int
   add_overflow (int a, int b)
   {
     if (b < 0)
       return a < INT_MIN - b;
     else
       return INT_MAX - b < a;
   }

add_overflow (a, b) returns 1 if a + b would overflow.
There are similar reliable tests for the other arithmetic operations.