On the Use of Term Rewriting for Performance Optimization of Legacy HPC Applications

Preparing codes for next generation supercomputer systems is anticipated to require significant changes to the optimization strategies employed in established HPC applications. In this paper, we present our experience in applying term rewriting transformations for the optimization of such applications. We have designed application-specific term rewriting transformations to improve the scalability, enhance locality and reduce the communication overhead of the Self-Consistent Field computational chemistry benchmark. We present the rationale for the use of term rewriting in this manner, the design of our transformations, and the much enhanced performance of the resulting code.