Xevtgen: Fortran code transformer generator for high performance scientific codes

HPC scientific codes are less readable and less manageable because of complex hand optimization which is often platform-dependent. We are developing a toolset that hopefully mitigates that maintainability problem by user-defined easy-to-use code transformation: The code is written in a simpler form, and coding technique for high performance is introduced by code transformations. In this paper, we present xevtgen, which is a code transformation generator of our toolset. Transformation rules are defined using dummy Fortran codes with some directives, and we expect that design makes it easier to learn for Fortran programmers. Some examples of code transformations are shown to discuss the practicality of the proposed approach.