[graphite] Weekly phone call notes

[Tobias Grosser <grosser at fim dot uni-passau dot de>]

Hi folks, hi graphities,

here you are with the latest notes from our graphite phone call.

It is also available on the wiki:

http://gcc.gnu.org/wiki/Graphite_Phone_Call/2009_05_06

All the best

Tobi


Attendees: Sebastian, Tobias, Christophe, Albert, Li, Jan, Razya,
Konrad, Antoniu 

      * Sebastian: 
              * Working on IVstack removal, 
              * Several other patches like "remove strcmp". (Will be
                committed as soon as possible) 
              * in clast-to-gimple: 
                      * There is a problem finding the type of induction
                        variables and upper bound expressions, as cloog
                        does not carry information about them. 
                              * We will try "unsigned long long" and
                                have to insert casts. (This might
                                trigger problems in the vectorizer and
                                might be slow. Maybe we can optimize the
                                size of the iv later.) Before: Used we
                                used the type of the old IV. But with
                                strip mining there is no 1 to 1 relation
                                in between ivs, so there is not always a
                                type. Other idea: infer types from upper
                                and lower bound expressions. But does
                                not seem to work either. This blocks the
                                work on removal IVSTACK. 
                      * Removal of IVStack: Blocked by types. But
                        already triggers some bugs. 
                      * Reductions: Blocking by IVSTack. 
      * Li: 
              * Mark loops as parallel with -fgraphite-force-parallel
                (committed). 
              * Trigger autopar with loop->can_be_parallel (committed). 
                
              * Started testsuite for graphite_autopar (sent for review
                to gcc-patches). 
              * 
              * Autopar fails in graphite branch on this line; 
------------------------------------------------------------------------
red = reduction_phi (reduction_list, reduc_phi);
      if (red == NULL)
      {
        if (dump_file && (dump_flags & TDF_DETAILS))
          fprintf (dump_file,
                   "  FAILED: it is not a part of reduction.\n");
        return false;
      }
------------------------------------------------------------------------

      * Tobias: 
              * Fix bugs to enable data reference building (Now only
                gfortran.dg/transpose_conjg_1.f90 fails). 
              * Bootstrapped dependency testing. Worked except one test
                case (gfortran.dg/cray_pointers_2.f90). 
              * Working on his paper about the polyhedral part of
                graphite to attract more research in this area. 
              * 
      * Jan: 
              * Got gcc summit paper accepted. Will be about the design
                of Graphite: IR, components of the Graphite
                infrastructure, testsuite, example, internals,
                integration with external prototyping tools (POCC). We
                should have some discussions about who describes what in
                graphite, as Tobias also has a paper accepted. 
              * Worked on the translation of PCP to Polyhedral
                representation.