Re: C/Ada performance comparison

["Jean-Pierre Rosen" <rosen@adalog.fr>]

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"Marin David Condic" <marin.condic.auntie.spam@pacemicro.com> a �crit dans le message news: 9i1qig$36o$1@nh.pace.co.uk...
> In general, I'd agree. However, there might be cases where this is not true.
> If, for example, I'm doing a lot of computations in a tight loop over a
> really large number of iterations, the constraint checking of numeric values
> might add a considerable overhead. Imagine you write X := X + 1 ; That ought
> to degenerate to a single add instruction with descent optimization, but if
> you have to do the computation then check that you have not exceeded the
> range of X's subtype and possibly do something to raise Constraint_Error,
> that single instruction can expand to quite a few. Do that in a tight loop a
> million times or so and you'll see some significant changes in performance.
>
Sure. But don't forget that you can put a pragma suppress in a declare block, so that it will affect only that sequence which is
truly critical, and not the 99% of the remaining code.

Too often, people think that checks are "on" or "off" for the whole program (which happens if you do that with a compiler option).
Ada provides finer granularity.

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           J-P. Rosen (rosen@adalog.fr)
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