GRAPHITE Two Years After: First Lessons Learned From Real-World Polyhedral Compilation
Konrad Trifunović, Albert Cohen, David Edelsohn, Feng Li, Tobias Grosser, Harsha Jagasia, Razya Ladelsky, Sebastian Pop, Jan Sjödin, Ramakrishna Upadrasta · 2010
Abstract. Modern compilers are responsible for adapting the semantics of source programs into a form that makes efficient use of a highly complex, hetero-geneous machine. This adaptation amounts to solve an optimization problem in a huge and unstructured search space, while predicting the performance outcome of complex sequences of program transformations. The polyhedral model of com-pilation is aimed at these challenges. Its geometrical, non-inductive semantics enables the construction of better-structured optimization problems and pre-cise analytical models. Recent work demonstrated the scalability of the main polyhedral algorithms to real-world programs. Its integration into production compilers is under way, pioneered by the graphite branch of the GNU Compiler Collection (GCC). Two years after the effective beginning of the project, this paper reports on original questions and innovative solutions that arose during the design and implementation of graphite. 1