IBM's Razya Ladelsky today outlined plans (thanks brbla) for providing automatic parallelization support within the GNU Compiler Collection. The Graphite Framework, which provides high-level loop optimizations based upon the polyhedral model, was merged for the forthcoming release of GCC 4.4 and it will be used eventually to provide some level of automatic parallelization support. Graphite will be combined with autopar, which is an automatic parallelization code generator based upon GOMP that in turn implements OpenMP. Once all of the work is completed, GCC will then be able to optimize some loops into running in parallel, which will yield better performance on multi-core systems. More on Razya's automatic parallelization plans can be found in this mailing list message:

There are two possible models for the code generation: 1. Graphite will annotate parallel loops and pass that information all the way through CLOOG to the current autopar code generator to produce the parallel, GOMP based code. 2. Graphite will annotate the parallel loops and CLOOG itself will be responsible of generating the parallel code. A point to notice here is that scalars/reductions are currently not handled in Graphite. In the first model, where Graphite calls autopar's code generation, scalars can be handled. After Graphite finishes its analysis, it calls autopar's reduction analysis, and only then the code generation is called (if the scalar analysis determines that the loop still parallelizable, of course). Once the first step is accomplished, the following steps will focus on teaching Graphite to find loop transformations (such as skewing, interchange etc.) that expose coarse grain synchronization free parallelism. This will be heavily based on the polyhedral data dependence and transformation infrastructures. We have not determined which algorithm/ techniques we're going to use for this part. Having synchronization free parallelization integrated in Graphite, will set the ground for handling parallelism requiring a small amount of parallelization. This is a rough view for our planned work on autopar in GCC. Please feel free to ask/comment.