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Re: type based aliasing again - meaning of "undefined"
On Sep 16, 1999, Marc Espie <espie@quatramaran.ens.fr> wrote:
> In article <19990915154954O.mitchell@codesourcery.com> you write:
>> const int i = 3;
>> int *ip = (int *)&i;
>> *ip = 2;
>> These programs will break when we do the (extremely beneficial
>> to conforming programs) optimization of assuming that `*ip'
>> cannot modify `i'.
> how are you going to deal with the `logical constness' idiom ?
Note that `i' is an actual const, not just a logical const, in this
program. If you just had a pointer to const int, and you couldn't
tell whether it is just logically constant, you wouldn't be able to
perform this optimization.
--
Alexandre Oliva http://www.dcc.unicamp.br/~oliva IC-Unicamp, Bra[sz]il
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