Re: Gnutools: consideration for upgrade to GCC 4.6

[Tomas Frydrych <tf+lists dot ecos at r-finger dot com>]

Hi,

On 17/01/12 16:09, Stanislav Meduna wrote:
> On 17.01.2012 10:36, Tomas Frydrych wrote:
>> Some of the more recent gccs were not producing usable binaries on some
>> platforms (including arm) with the -Os option. I do not know if this is
>> the case with 4.6.2, and I don't think ecos uses -Os by default, but it
>> is probably worth checking whether this works (and at least documenting
>> somewhere if it does not).
> 
> Do you happen to have more details on this - versions, flags used,
> example to reproduce...?
> 
> http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html says
> 
>   -Os enables all -O2 optimizations that do not typically increase
>   code size. It also performs further optimizations designed
>   to reduce code size.
> 
> it would be good to know whether the problems come from -O2 (which
> would be a major problem) or from these further optimizations.

It was known to be present in gcc 4.5.1, and it was not effecting the
-O2 option, only -Os. The openembedded/yoctoproject guys run into it
building u-boot, and it was mentioned yesterday on the poky mailing
list,
https://lists.yoctoproject.org/pipermail/poky/2012-January/007472.html.

Tomas