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Re: undocumented optimization options

Mark Mitchell <> 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 
> > side-effects (like performing function versioning for ipa-cp) 
> those should be
> > documented.
> > 
> > For example googling for "interprocedural constant propagation" gives 
> > an idea what it does by citing papers.  Googling for "matrix 
> > 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.
> ==

Described these two optimizations in more detail.
O.K now?


2007-11-20  Razya Ladelsky <>

    * doc/invoke.texi (fipa-cp, fipa-matrix-reorg): Add documentation.

> -- 
> Mark Mitchell
> CodeSourcery
> (650) 331-3385 x713

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