[wplug] Compiler questions

[Burt E Reany]

   There IS such an optimised compiler - but it's the proprietary compiler
provided by a manufacturer for their hardware family. Proprietary and
process control equipment that need such intense thruput, either due to
load factors or marketing requirements, are therefore both restrictive and
expensive. Open source systems don't pretend to wring such intensive use
out of every hardware platform, but provide consistancy across hardware
boundaries, and support migration between hardware families.
   In addition, the unavailability of source code for proprietary systems
posts a disadvantage to the application developers in that environment that
open source developers don't suffer from.

    (What's that I just fell off of?  It says "Lux Flakes". Shto eto?)


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                      Tom Rhodes                                                                                           
                      <trhodes                  To:      General user list <wplug at wplug.org>                               
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                      02/03/2005 02:45                                                                                     
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On Thu, 3 Feb 2005 08:44:43 -0500
Bill Moran <wmoran at potentialtech.com> wrote:

> Burt E Reany <breany at csc.com> wrote:
> >
> > They used to tell me that about good COBOL, as well - -
> >
> >> I heard  well written C code compiled with architecture specific and
> >> other optimizations has a trivial difference with native assembler
> >> code.
>
>
http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/x86.html

>
> If you read through that tutorial, I think you'll realize that any
compiled
> language is very unlikely to be as optimized as well-written assembly.
The
> article talks about certain optimizations that I simply can't imagine a
> compiler being able to make.

Does the Intel C Compiler produce better binaries than GCC?  Yes,
true optimisation would come more effectively if you did not need
to build support for every architecture known into the compiler.
Same goes with languages.  It would be really nice if there was
effectively a compiler for each architecture which would make use
of every known optimization available; however, I'm not sure who
would be insane enough to put forth this effort.

There are of course language optimizations; for instance if you
would store data in the stack in place of buffers, that shaves
off a few picoseconds here and there, and can be extremely useful
on large applications; however, daunting.  Wonder how effective
that would be in, for instance, KDE.

And surprisingly, throughout this entire conversation, I have not
heard the words "warning levels" at all.

--
Tom Rhodes
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