GCC 4.2.0 Status Report (2007-02-19)

[Richard Guenther]

On 2/20/07, Vladimir Makarov <vmakarov@redhat.com> wrote:
> Richard Guenther wrote:
>
> > On 2/20/07, Vladimir Makarov <vmakarov@redhat.com> wrote:
> >
> >> As for proposal to revert the aliasing fixes on the 4.2, IMHO aliasing
> >> bugs are pretty nasty it is hard to find a option to work around because
> >> alias info is used in many optimizations.
> >
> >
> > All bugs we are talking about can be worked around by using
> > -fno-strict-aliasing.
> >
> It is too conservative and I think seriously descreases performance
> too.  Although it would be interesting to see what degradation we would
> have with usage of the option. May be it is not so bad. In that case,
> your proposal would be reasonable because it is much less work.

Well, in case you need to decide between wrong-code or decreasing performance
I'd choose decreasing performance ;)  I only wanted to make the point that
reverting the patches in question will not introduce wrong-code bugs that cannot
be worked around.  If the working around is convenient or if the wrong-code
bugs are easy to spot is another question, but in theory we have all
these issues
with 4.1 as well.  So to clarify, I didn't suggest that we or the
casual user should
use -fno-strict-aliasing by default.

Richard.