Re: comparing gnat/Ada95 and g77

[Gary Scott <scottg@flash.net>]

Hi,

Jean-Marc Bourguet wrote:
> 
> Gary Scott <scottg@flash.net> writes:
> 
> > Hi,
> > Gerald Kasner wrote:
> > >
> > > Reinert Korsnes schrieb:
> > > >
> > > > Hi,
> > > <snip>
> > >
> > > It's the algorithm, not the language that matters.
> >
> > Actually, the design of the language is quite significant it terms of
> > how easy it makes it to design a suitable optimizer.  FORTRAN 77 should
> > be very easy to optimize so long as you're not using integer pointers
> > and/or aliasing.  Fortran 95 is only slightly less "optimizable".
> > C-based languages are somewhat harder to optimize typically because they
> > ENCOURAGE use of pointers and various aliasing tricks.
> 
> That's not the case of Ada.  It is perhaps worse than Fortran, but is
> far better than C and C++ on this aspect.

That's what I would have expected.  

> 
> > However, some of the difference between Fortran compilers and other
> > languages has something to do with the fact that there are companies
> > with 30+ years experience tweaking their compiler (the FORTRAN 77
> > ones are largely mature, not to say that all intrinsics are optimal,
> > I keep seeing horrible performance with simple things like circular
> > shift).
> 
> Another thing is that raw performance is an important factor in the
> Fortran market.

True.  However, high-level "expressiveness" is dramtically improved by
Fortran 95 and I think that many OO buffs will very much like the
improvements in the upcoming standard.  Still, we just can't seem to get
a proper bit string/array type into the standard (or unsigned integers,
or ...).  If it can't be defined in a 100% portable way, it seems that
it won't be considered either.  Ada (and PL/1) will probably always be
ahead in terms of "features" (simply syntactic sugar in some
cases)...unless Ada stops being developed.  I doubt whether Fortran will
ever incorporate OS dependent features like
multi-tasking/threading/processes.  It is increasingly supporting
parallel processing constructs, though.

> 
> Yours,
> 
> --
> Jean-Marc


-- 

Gary Scott
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