Re: Bug in 'gnatmake' (Was: Range check for type 'Integer')

[Peter Brooks <peter.h.m.brooks@gmail.com>]

On Jun 17, 11:22 pm, Jeffrey Carter
<spam.jrcarter....@spam.not.acm.org> wrote:
> On 06/17/2013 12:15 PM, Peter Brooks wrote:
>  >
>  > Leaving on range, and other, checking must slow things down a tad, but
>  > turning the optimiser on must speed them up. It'll only really matter
>  > in CPU intensive stuff, but do you have any idea what the effects are?
>  > More or less.
>
> IMO, leaving on checks speeds things up a bit, if you're interested in correct
> code; code without buffer-overflow and integer-overflow vulnerabilities and the
> like. An Ada compiler can optimize away many index checks, for example, which
> doesn't happen to checks manually inserted in a language without automatic
> checks. So it should be the case that correct code in Ada is faster than
> equivalent code in a language without automatic checks.
>
> Of course, if correctness isn't an issue, then things might work otherwise. But
> if correctness isn't an issue, the null program should be an acceptable solution
> to any problem, and that should be just as fast in Ada as in any other language.
>
>  > I know I could just take my code and try it, but it'd be interesting
>  > to have a bigger picture of the performance question.
>
> There's always the Ada (83) beats assembler paper:
>
> http://www.seas.gwu.edu/~adagroup/sigada-website/lawlis.html
>
Thank you for that - I'd not read it. It makes the point very well!