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Re: undocumented optimization options


On Nov 20, 2007 12:32 PM, Razya Ladelsky <RAZYA@il.ibm.com> wrote:
> Mark Mitchell <mark@codesourcery.com> wrote on 12/11/2007 18:25:03:
>
>
> > Richard Guenther wrote:
> >
> > > For options that are not enabled by default at any -O level the
> > documentation
> > > should be a help for the user to decide whether to enable or not
> enable it.
> > > So, yes, if there are non-standard terms used or if there are not
> obvious
> > > side-effects (like performing function versioning for ipa-cp)
> > those should be
> > > documented.
> > >
> > > For example googling for "interprocedural constant propagation" gives
> you
> > > an idea what it does by citing papers.  Googling for "matrix
> flattening
> > > transposing" instead gives you only patches ;)
> >
> > To echo Richard: this is a user manual, so we don't need to say exactly
> > what the option does, but we have to say when you should use it. :-)  In
> > other words, we certainly don't want to say anything about SSA names or
> > whatever, but we do want to explain what it's for.  For interprocedural
> > constant propagation, maybe something like:
> >
> > ==
> > This optimization analyzes the program to determine when values passed
> > to, or return from, functions are constants and then optimizes
> > accordingly.  This optimization can substantially increase performance
> > if the application has lots of functions that return constants, but,
> > because this optimization can create multiple copies of code fragments,
> > it may significantly increase code size.
> > ==
> >
>
> Thanks.
> Described these two optimizations in more detail.
> O.K now?

Ok.  Thanks!
Richard.

> Thanks,
> Razya
>
> 2007-11-20  Razya Ladelsky <razya@il.ibm.com>
>
>     * doc/invoke.texi (fipa-cp, fipa-matrix-reorg): Add documentation.


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