This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: GCC mini-summit - compiling for a particular architecture
- From: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>
- To: Laurent GUERBY <laurent at guerby dot net>
- Cc: Robert Dewar <dewar at adacore dot com>, Steve Ellcey <sje at cup dot hp dot com>, aaw at google dot com, kenneth dot hoste at elis dot ugent dot be, gcc at gcc dot gnu dot org
- Date: Sun, 22 Apr 2007 14:00:08 +0200
- Subject: Re: GCC mini-summit - compiling for a particular architecture
- References: <1177177666.6004.158.camel@pc2>
> Look from what we're starting:
>
> <<
> @item -funroll-loops
> @opindex funroll-loops
> Unroll loops whose number of iterations can be determined at compile
> time or upon entry to the loop. @option{-funroll-loops} implies
> @option{-frerun-cse-after-loop}. This option makes code larger,
> and may or may not make it run faster.
>
> @item -funroll-all-loops
> @opindex funroll-all-loops
> Unroll all loops, even if their number of iterations is uncertain when
> the loop is entered. This usually makes programs run more slowly.
> @option{-funroll-all-loops} implies the same options as
> @option{-funroll-loops},
> >>
>
> It could gain a few more paragraphs written by knowledgeable people.
> And expanding documentation doesn't introduce regressions :).
but also does not make anyone actually use the options. Nobody reads
the documention. Of course, this is a bit overstatement, but with a
few exceptions, people in general do not enable non-default flags.
Zdenek