[gsoc] Generic addressing mode selection

[Erik Varga <erik dot varga256 at gmail dot com>]

Hi all,

I'm Erik KrisztiÃn Varga, a 2nd year Electrical Engineering student,
and I'd be interested in contributing to gcc as part of GSoC 2015.
I'd like to work on adding an addressing mode selection pass to the
RTL based on the ideas described in Eckstein et. al.'s paper on the
subject [1].
The basic idea is to reduce the problem to a Partitioned Boolean
Quadratic Programming (PBQP) problem and to find a close-to-optimal
solution with a heuristic algorithm. It should be possible to model a
lot of addressing modes with the cost matrix approach described in the
paper, so this would be a generic way to do AMS for different
architectures.

Quite a few things would have to be done to implement the algorithm,
like finding the correct models for the various addressing
instructions in the supported architectures, or implementing an
efficient representation of the cost vectors and matrices, but I think
it should be possible in the scope of a Summer to have at least a
working prototype ready.
Would someone be interested in mentoring this project for GSoC? Is
there anything similar currently being worked on? I think Oleg Endo
has started implementing such a pass a while ago (mentioned in
PR56590).

Best regards,
Erik

[1] http://sydney.edu.au/engineering/it/~scholz/publications/cgo03.pdf