Bug#847397: libimager-perl FTBFS on mips/mipsel: Failed 10/66 test programs

[Niko Tyni]

On Fri, Dec 09, 2016 at 11:39:58AM +1100, Tony Cook wrote:
> On Fri, Dec 09, 2016 at 01:01:01AM +0100, gregor herrmann wrote:
> > On Fri, 09 Dec 2016 01:14:23 +0200, Niko Tyni wrote:
> > 
> > > TL;dr: this is https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78176

> > > Unfortunately gcc doesn't seem to have a targeted option to disable this
> > > optimization. Building with -O0 on mips and mipsel is probably the best
> > > workaround we have (-O1 isn't enough.)

> > +# #847397
> > +DEB_HOST_ARCH = $(shell dpkg-architecture -qDEB_HOST_ARCH)
> > +NOOPT = mips mipsel amd64
> > +ifneq (,$(filter $(DEB_HOST_ARCH), $(NOOPT)))
> > +export DEB_CFLAGS_MAINT_STRIP:=-O2
> > +export DEB_CFLAGS_MAINT_APPEND:=-O0
> > +endif

> That certainly looks like a sensible workaround.

Looks good to me too.

> Is there some mechanism that will remove it if the gcc (or perhaps
> kernel) bug is fixed?

The only way I can think of is building and running a test case during
every build and setting the gcc flags based on that. But I suppose this
would give a false negative when building on 'real' 32-bit systems that
don't exhibit the problem, yielding binaries that fail on 64-bit systems.
And it feels overkill to me anyway.

We could leave a bug open about the disabled optimization and hope that
somebody will review the bugs at some point...
-- 
Niko