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RE: -fno-tree-cselim not working?
On Fri, 2007-10-26 at 17:31 +0100, Dave Korn wrote:
> On 26 October 2007 17:11, Andrew Haley wrote:
> Is the problem that POSIX doesn't make the distinction between as-if and
> actual behaviour that is such an essential part of the C standard?
The 'as-if' rule is present in ALL Standards of all kinds,
it is a consequence of the fact that a standard is a method
of judging whether something is non-conforming by performing
experiments on it, recording observations, and comparing
them with predictions.
Although the required behaviour is specified using an abstracted
model, only the requirements on observable properties have
any significance for the experiments: the virtual properties
are just semantic 'temporaries' used to make the predictions.
Optimisations use a different model from the one specified,
but the models are (hopefully!) congruent in the predictions
made for observables.
--
John Skaller <skaller at users dot sf dot net>
Felix, successor to C++: http://felix.sf.net