[PPL-devel] Problems with test suite on alpha

[Roberto Bagnara]

Michael Tautschnig wrote:
> I've reported problems with some test cases because of suspected gcc bugs on
> alpha earlier already. Now it seems that even more test cases are broken, most
> probably because of the very same bug (I suspect it to be
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=8966). My question now is: How to
> proceed? Shall I specifically disable the failing test cases by surrounding them
> with an #ifndef __alpha__ or disable the entire test suite on alpha?

Hi Michael,

from what you write, there is a bug in GCC concerning exception handling on
the Alpha.  Strictily speaking, the PPL uses exception handling, so if that
does not work on the Alpha, the PPL does not work on the Alpha.  And there
is nothing to do but fix the GCC bug.

However, if that GCC bug really only affects exception handling and nothing
else, given that the PPL only uses exceptions for error reporting, we can
probably say that the PPL works on the Alpha *apart* from error reporting.

Let us focus on the role of PPL for Graphite (which uses the C interface):
I believe that this application does not exploit the ability of PPL to
continue after an out-of-memory condition or an arithmetic-overflow.
If this is true, then any error raised by the PPL would cause an ICE in GCC.
If dying with an uncaught exception is considered not significantly worse
than dying with an ICE, then there should be no problem.
In this hypothesis, the failures you observe are only for test programs
that exercise the error-reporting capabilities of the PPL: I would disable
just those on the Alpha.

Then the Debian/Alpha users should probably be warned that the PPL package
they have does not possess all the properties explained in the PPL
documentation, i.e., all the error reporting features are badly broken.
Cheers,

    Roberto

-- 
Prof. Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara at cs.unipr.it