[PPL-devel] PPL 0.10 testsuite failures on powerpc-linux

[Janis Johnson]

On Mon, 2009-02-02 at 18:31 +0100, Roberto Bagnara wrote:
> Janis Johnson wrote:
> > I'm trying to build the Parma Polyhedra Library on powerpc-linux so I
> > can use it for Graphite support in GCC.  I've tried a lot of things
> > and my builds normally succeed but I get lots of testsuite failures:
> > 
> >   in Box, 60 tests with -DBOX_INSTANCES=db_r_oc
> >   in Octagonal_Shape, 58 tests with -DOCTAGONAL_SHAPE_INSTANCE=double
> >   in BD_Shape, 59 tests with -DBD_SHAPE_INSTANCE=double
> 
> Hi Janis,
> 
> we investigated your report and found the culprit.  The immediate cause
> is a bad interaction between Autoconf's AC_C_BIGENDIAN and
> AX_PREFIX_CONFIG_H.  We reported this problem a few days ago, but did
> not get any reply:
> 
>      http://www.cs.unipr.it/pipermail/ppl-devel/2009-January/013958.html
> 
> Perhaps AX_PREFIX_CONFIG_H is no longer maintained and we decided to
> drop it starting from PPL 0.11.
> 
> Now, what happens is that AX_PREFIX_CONFIG_H fails to rename
> WORDS_BIGENDIAN as PPL_WORDS_BIGENDIAN.  The PPL, however,
> expects (only in three places, in src/Float.defs.hh) the
> symbol PPL_WORDS_BIGENDIAN to be defined on big-endian machines
> such as PowerPC.
> 
> A workaround is to configure the PPL for big-endian
> architectures specifying
> 
>      CPPFLAGS="-UWORDS_BIGENDIAN -DPPL_WORDS_BIGENDIAN=1"
> 
> at the end of the configure command.  Can you please check
> that that works?  If it does we will immediately publish
> a notice on the PPL web site.

Yes, it works!  All tests pass (29 lines in output from "make -k
check" match "^All tests").

I assume you mean you'll add an entry to the known bugs list;
that's where I first checked when looking into the test failures.

> Taking into account that GCC 4.4 (via CLooG) does not use
> any PPL feature depending on that miscompilation, I wonder
> what is best.  Do you think we should prepare a PPL 0.10.1 release
> with that fix?

I don't think so, it should be enough to have the workaround in
the known bugs list.

> Concerning how such a thing could have happened, the problem
> is that we have access to only one PowerPC machine.  That machine
> has memory problems so that a make of the PPL terminates with
> a segmentation fault in GCC 90% of the times.  So, basically,
> we currently have no sensible way to test on PowerPCs.  It is
> a pity that this caused PPL 0.10 to be shipped with such a bug.
> Thanks again for the problem report,

I can build and test CVS sources occasionally and report problems.
When I can successfully build gmp/mpfr/ppl/cloog as 32-bit libraries
on powerpc64-linux I plan to try as 64-bit libraries.  Once that
works with released versions I can try with CVS sources of some or
all of them.

Thanks for the quick response.

Janis