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Re: Do C++ signed types have modulo semantics?

Steven Bosscher wrote:
On Wednesday 29 June 2005 20:01, Daniel Berlin wrote:

So i would advise anyone arguing against turning on -fwrapv simply
because it doesn't seem to hurt us at O2.



wtf, "doesn't seem to hurt us at -O2".  Look again at the 64 bits
numbers!  Losing 5% on the fp benchmarks is a serious regression.
Even without exercising the heavy-ammo loop optimizers, -fwrapv is
a serious performance-hurter.


Still these figures are very interesting for Ada, where I am afraid
the kludge we do in the front end for required overflow checking is
much more expensive than these figures indicate. Of course this will
be *highly* target dependent.

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