Re: comparing gnat/Ada95 and g77

[Jean-Marc Bourguet <jm@bourguet.org>]

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.

> 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. 

Yours,

-- 
Jean-Marc