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[Bug libstdc++/22200] numeric_limits<signed>::is_modulo is inconsistent with gcc


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22200

Gabriel Dos Reis <gdr at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |gdr at gcc dot gnu.org

--- Comment #41 from Gabriel Dos Reis <gdr at gcc dot gnu.org> 2012-02-29 13:36:59 UTC ---
(In reply to comment #40)
> I haven't seen it mentioned in the discussion here, but in C++11, the
> definition of is_modulo was clarified as:
> 
> "True if the type is modulo. A type is modulo if, for any operation involving
> +, -, or * on values of that type whose result would fall outside the range
> [min(),max()], the value returned differs from the true value by an integer
> multiple of max() - min() + 1."
> 
> Do people have objections to switching numeric_limits<signed>::is_modulo to
> false (setting it to true when -fwrapv is used can still be discussed
> afterwards)?


I agree with this.  Thanks, Marc.


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