Automated Programmable Control and Parameterization of Compiler Optimizations

We present a framework which effectively combines programmable control by developers, advanced optimization by compilers, and flexible parameterization of optimizations to achieve portable high performance. We have extended ROSE, a C/C++/Fortran source-to-source optimizing compiler, to automatically analyze scientific applications and discover optimization opportunities. Instead of directly generating optimized code, our optimizer produces parameterized scripts in POET, an interpreted program transformation language, so that developers can freely modify the optimization decisions by the compiler and add their own domain-specific optimizations if necessary. The auto-generated POET scripts support extra optimizations beyond those available in the ROSE optimizer. Additionally, all the optimizations are parameterized at an extremely fine granularity, so the scripts can be ported together with their input code and automatically tuned for different architectures. Our results show that this approach is highly effective, and the code optimized by the auto-generated POET scripts can significantly outperform those optimized using the ROSE optimizer alone.