Automatic parallelization of C by means of language transcription

Abstract. The automatic parallelization of C has always been frustrated by pointer arithmetic, irregular control flow and complicated data aggregation. Each of these problems is similar to familiar challenges encountered in the parallelization of more rigidly-structured languages such as FORTRAN. By creating a mapping from one language to the other, we can expose the capabilities of existing automatically parallelizing compilers to the C language. In this paper, we describe our approach to mapping applications written in C to a form suitable for the Polaris source-tosource FORTRAN compiler. We also describe the improvements in the compiled applications realized by this second level of transformation and show results for a small application in comparison to commercial compilers. Polaris is a automatically parallelizing source-to-source FORTRAN compiler. It accepts FORTRAN77 input and produces a FORTRAN output in a new dialect that supports explicit parallelism by means of embedded directives such as the OpenMP [Ope97] or Sun FORTRAN Directives [Sun96]. The benefit that Polaris provides is in automating the analysis of the loops an