Hi,
to keep everybody updated what is happening in the GRAPHITE branch, I
would like to post the notes of our weekly phone call.
Attendees: Razya, Li, Konrad, Jan, Tobi, David, Sebastian, Christophe
Discussed topics:
* Data dependencies: Tobias committed a patch filling the access
polyhedrons
* Not yet enabled as there are some bootstrap bugs
* All arrays access the same alias set
* Reductions are not yet included in the access
polyhedrons (Same as last week, but now really
committed)
* Bug in building of scattering matrices fixed.
* Bug in condition detection on its way to be fixed.
* Automatic Parallelization:
* Li will start integrating graphite and code generation
(If his summer of code proposal is accepted)
* Mark all loops parallel if new flag
"-fgraphite-force-parallel" is set.
* How to connect auto par?
* Directly in graphite code generation (clast to
gimple): We call the autopar backend after
generating a serial gimple loop. This is the
easiest approach. Also we still access to the
polyhedral information so we can use it to give
autopar more information.
* By annotating loops: In the graphite pass we
annotate gimple loops as parallel . Later the
autopar pass is scheduled, which bypasses its
analysis if it sees a loop annotated parallel.
This allows to schedule scalar optimizations in
between graphite and autopar, but we loose the
polyhedral information. As we do not need the
additional information, but we definitely need
some scalar optimization like PRE the
"annotating loops" approach seems to be our
first try.
The notes of all calls are available on the wiki:
http://gcc.gnu.org/wiki/Graphite_Phone_Call
More information about graphite at:
http://gcc.gnu.org/wiki/Graphite
Tobi
