Re: Optimization techniques

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From	"Rick C. Hodgin" <rick.c.hodgin@gmail.com>
Newsgroups	comp.compilers
Subject	Re: Optimization techniques
Date	Thu, 18 Apr 2019 11:22:24 -0400
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On 4/18/2019 4:07 AM, George Neuner wrote:
> On Wed, 17 Apr 2019 09:42:21 -0400 (EDT), "Rick C. Hodgin"
> <rick.c.hodgin@gmail.com> wrote:
>
>> Are there resources someone can point me to for learning more about
>> time-honored, long-established, safely applied, optimization
>> techniques for a C/C++ like language?
>
> There really aren't many "safe" optimizations you can do before you
> run into pointer aliasing problems in C.  Almost any modern compiler
> text will cover the bulk of them.

I'm not sure what that is by its name, but I'll start there.  Thank
you, George.

> [Great reading list, thanks.  Floating add and multiply commute but
> they don't associate.  a+b should be the sams as b+a, but (a+b)+c not
> the same as a+(b+c).  -John]

I think the goal for floating point engines in moving forward is no
longer to only be exceeding fast under IEEE-754 or its relatives, but
there should be a new model introduced into silicon which carries out
computations that are truly accurate, which either an arbitrary pre-
cision engine which will admittedly be slower and be accurate out only
to some finite degree and inaccurate beyond that, or some kind of sym-
bolic tree-based algorithm which doesn't actually conduct the final
computation until the tree has been updated to its final form, and is
then, and only then, computed, allowing for cancellations and reduc-
tions to be made, which I believe is what happens in apps like Maple
and Mathematica.

--
Rick C. Hodgin
[I think you're conflating different things in the FP stuff.  The
sorts of analysis that Maple and Mathematica do require looking
at potentially large amounts of data and deciding on the fly how
to do the calculations.  It might be reasonable to do some of that
in hardware, but I think most of it is too complicated.  -John]

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Optimization techniques "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-04-17 09:42 -0400
  Re: Optimization techniques Hans Aberg <haberg-news@telia.com> - 2019-04-17 18:11 +0200
  Re: Optimization techniques George Neuner <gneuner2@comcast.net> - 2019-04-18 04:07 -0400
    Re: Optimization techniques "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-04-18 11:22 -0400
      Re: Optimization techniques George Neuner <gneuner2@comcast.net> - 2019-04-19 15:48 -0400
    Re: Optimization techniques Hans Aberg <haberg-news@telia.com> - 2019-04-19 00:52 +0200
  Re: Optimization techniques Kaz Kylheku <847-115-0292@kylheku.com> - 2019-04-19 08:49 +0000
    Re: Optimization techniques "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-04-19 11:48 -0400
      Re: Optimization techniques David Brown <david.brown@hesbynett.no> - 2019-04-23 09:38 +0200
    Re: Optimization techniques David Brown <david.brown@hesbynett.no> - 2019-04-23 09:18 +0200
  Re: Optimization techniques Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2019-04-20 00:27 +0200
    Re: Optimization techniques "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-04-19 16:11 -0700
      Re: Optimization techniques Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2019-04-20 19:47 +0200
        Re: Optimization techniques "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-04-24 10:16 -0400
    Re: Optimization techniques George Neuner <gneuner2@comcast.net> - 2019-04-20 18:59 -0400
    Re: Optimization techniques David Brown <david.brown@hesbynett.no> - 2019-04-23 09:43 +0200
      Re: Optimization techniques Martin Ward <martin@gkc.org.uk> - 2019-04-26 20:10 +0100
        Re: Optimization techniques Kaz Kylheku <847-115-0292@kylheku.com> - 2019-04-26 21:11 +0000
        Re: Optimization techniques David Brown <david.brown@hesbynett.no> - 2019-04-28 17:22 +0200
          Re: Optimization techniques Gene Wirchenko <genew@telus.net> - 2019-04-30 18:07 -0700
            Re: Optimization techniques David Brown <david.brown@hesbynett.no> - 2019-05-01 09:03 +0200
    Re: Optimization techniques "Derek M. Jones" <derek@_NOSPAM_knosof.co.uk> - 2019-04-26 13:39 +0100
  Re: Optimization techniques rockbrentwood@gmail.com - 2019-09-26 20:35 -0700

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