Re: optimization issue about -O2 and -Os

[Ebony Zhu <ebony dot zhu at motorola dot com>]

Have you ever been troubled in the same problem? Are you sure it's a gcc
bug, and not a mistake I probably made when building the cross tool?
(e.g. missed some important options when building gcc).

B.R
Ebony

On Fri, 2004-04-30 at 06:58, Jim Wilson wrote:
> Ebony Zhu wrote:
> > build some applications such as U-Boot, Busybox..., with the -Os
> > optimization, the apps can be built but cannot run (just halted, there
> > were even no error messages). If I use -O2 switch then everything is OK.
> > 
> > According to manpage of GCC, -Os is based on -O2 switch and does some
> > work to reduce the code size. What GCC did on earth with the -Os switch?
> 
> The -Os option is buggy.  You might want to report a bug into our 
> bugzilla bug datase.  See
>      http://gcc.gnu.org/bugs.html
> for more info on reporting bugs.
> 
> Though the -Os option is based on the -O2 option, it is a different 
> option, that generates different code, and has different bugs.
> -- 
> Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com