Re: [s390] Build failure with gcc 4.9.2 in rawhide

[Joseph Myers <joseph at codesourcery dot com>]

On Mon, 26 Jan 2015, Andreas Krebbel wrote:

> Hi Siddhesh,
> 
> On 01/23/2015 08:43 AM, Siddhesh Poyarekar wrote:
> > Hi Andreas,
> > 
> > We encountered a build failure in rawhide for s390x due to -Werror:
> > 
> > http://s390.koji.fedoraproject.org/koji/getfile?taskID=1705688&name=build.log&offset=-24000
> > 
> > I was able to narrow it to a small reproducer and have filed it as a
> > bug in gcc:
> > 
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64739
> > 
> > I have unbroken the build temporarily in Fedora by disabling werror
> > for s390x.  Could you please have this patched in glibc before the
> > release?
> 
> the difference between S/390 and common code (gconv_simple.c) appears to 
> be that we define STORE_REST and gconv_simple.c doesn't. This triggers 
> the GCC bug. Your reduced testcase fails on x86 as well. When I replace 
> the !STORE_REST code in gconv_simple.c with the STORE_REST code from 
> loop.c I get the same error message on x86. So to my understanding there 
> is nothing to do apart from fixing GCC - right?!

Well, if the warning appears with GCC 4.9, then suppressing with DIAG_* 
macros (conditional on STORE_REST), naming 4.9 as the relevant version, 
would seem appropriate - the comment should reference the GCC bug, so 
making it easy to tell at what point the suppression can be removed (e.g. 
when moving to GCC 5 as minimum version, if the bug gets fixed in GCC 5).

-- 
Joseph S. Myers
joseph@codesourcery.com