Optimization opportunities based on the polyhedral model in GRAPHITE How much impact has GRAPHITE already? Tobias

The polytope model is used since many years to describe standard loop optimizations like blocking, interchange or fusion, but also advanced memory access optimiza-tions and automatic parallelization. Its exact mathemat-ical description of memory accesses and loop iterations allows to concentrate on the optimization problem and to take advantage of professional problem solving tools developed for operational research. Up to today the polytope model was limited to research compilers or source to source transformations. Graphite generates a polytope description of all programs com-piled by the gcc. Therefore polytope optimization tech-niques are not limited anymore to hand selected code pieces, but can actually be applied in large scale on real world programs. By showing the impact of GRAPHITE on important benchmarks- “How much runtime is actu-ally spent in code, that can be optimized by polytope op-timization techniques? "- we invite people to base their current polytope research on GRAPHITE to make these optimizations available to the large set of gcc compiled applications.