[Buildroot] [PATCH] package/kmsxx: work around gcc bug 85180

[Thomas Huth <huth@tuxfamily.org>]

Am Fri, 7 Jun 2019 08:39:07 +0200
schrieb Giulio Benetti <giulio.benetti@micronovasrl.com>:

> Hello Thomas H.,
> 
> adding Thomas P.+
> 
> Il 07/06/2019 08:08, Thomas Huth ha scritto:
> > Am Thu,  6 Jun 2019 15:10:35 +0200
> > schrieb Giulio Benetti <giulio.benetti@micronovasrl.com>:
> >   
> >> With Microblaze Gcc version < 8.x the build hangs due to gcc bug
> >> 85180: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85180. The bug
> >> shows up when building kmsxx with optimization but not when
> >> building with -O0. To work around this, if
> >> BR2_TOOLCHAIN_HAS_GCC_BUG_85180=y we force using -O0.  
> > 
> > According to the description in the bugzilla, the bug should also go
> > away when compiling with -fno-dse ... so wouldn't it be better to
> > use "-fno-dse" here instead of disabling the optimizations
> > completely?  
> 
> Honestly I've completely missed that possible solution and didn't
> even tested.
> 
> Anyway it's been discussed on IRC channel to keep a common work
> around for every different GCC_BUG_*, so since many packages are
> affected by Bug 85180 and -O0 seemed to work every time Thomas P.
> suggested to always keep that flag as solution.

Well, if -fno-dse is also "fixing" this bug, maybe you could add
"-fno-dse" to the global compiler flags instead of manually fixing each
and every package with -O0? ... anyway, just my 0.02 ?.

 Thomas H