Spatial Based Feature Generation for Machine Learning Based Optimization Compilation

Modern compilers provide optimization options to obtain better performance for a given program. Effective selection of optimization options is a challenging task. Recent work has shown that machine learning can be used to select the best compiler optimization options for a given program. Machine learning techniques rely upon selecting features which represent a program in the best way. The quality of these features is critical to the performance of machine learning techniques. Previous work on feature selection for program representation is based on code size, mostly executed parts, parallelism and memory access patterns with-in a program. Spatial based information-how instructions are distributed with-in a program-has never been studied to generate features for the best compiler options selection using machine learning techniques. In this paper, we present a framework that address how to capture the spatial information with-in a program and transform it to features for machine learning techniques. An extensive experimentation is done using the SPEC2006 and MiBench benchmark applications. We compare our work with the IBM Milepost-gcc framework. The Milepost work gives a comprehensive set of features for using machine learning techniques for the best compiler options selection problem. Results show that the performance of machine learning techniques using spatial based features is better than the performance using the Milepost framework. With 66 available compiler options, we are also able to achieve 70% of the potential speed up obtained through an iterative compilation.