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Re: loop optimization in gcc
On Wed, 2009-10-14 at 23:56 +0530, sandeep soni wrote:
> On Wed, Oct 14, 2009 at 9:02 PM, Tobias Grosser
> <grosser@fim.uni-passau.de> wrote:
> > On Wed, 2009-10-14 at 20:12 +0530, sandeep soni wrote:
> >> > Hi,
> >> >
> >> > you also might want to take a look at the Graphite project.
> >> > http://gcc.gnu.org/wiki/Graphite where we do loop optimizations and
> >> > automatic parallelization based on the polytop model. If you need any
> >> > help feel free to ask.
> >> >
> >> > Tobias
> >> >
> >> >
> >>
> >> Hi,
> >>
> >> This seems to be quite interesting and challenging.Moreover,it is very
> >> close to what we are trying to achieve as well (on a small scale that
> >> is).I have started preliminary reading on the polytope model and the
> >> working of GRAPHITE. I will ask you if i face any doubts.It would be
> >> nice to contribute to this project.
> >>
> >>
> >> For the starters, can you tell me if GRAPHITE also does source to
> >> source transformations or otherwise to optimize??Coz i had read
> >> somewhere else that the polyhedral model used source to source
> >> transformations.
> >
> > Hi,
> >
> > you are right. There are several polytope frameworks that work on the
> > source code level (LooPo, Cloog/Clan from Cedric Bastoul), however
> > Graphite works on the intermediate level tree-ssa in gcc. Therefore we
> > can not do any source to source transformations.
> > The idea is to not be limited to specific input languages or special
> > formatting of the code, but to be able to use the powerful analysis in
> > the gcc middle end.
> > This allows us to work on any input language and to detect loops that do
> > not even look like a loop in the input program (goto-loops). Using the
> > powerful scalar evolution framework in gcc Graphite also handles loops
> > that do not look like affine linear loops.
> > This is a powerful approach in its earlier stages. Basic loops and
> > simple code transformations already work, but there is still a lot left
> > to be done.
> >
> > Tobi
> >
> >
>
> Hi,
>
> Sounds absolutely convincing to me. I am too keen to contribute in
> this in any way possible.I will first try to understand how it works
> totally .Would you mind me pressing on with some of issues in the near
> future? I am afraid though that they might be a bit more theoretical
> to begin with.
Sure. Just drop me a line