A High-Level Interface of Xevolver for Composing Loop Transformations

Xevolver is a code transformation framework under active development to help legacy application migration to extreme-scale computing systems. The framework originally assumes that transformation rules are written in XSLT, which might be too low-level for standard users to express their own rules. Hence, this article describes a high-level interface of the Xevolver framework, which offers an easy and declarative way to define a custom compiler directive associated with a composite of predefined loop transformation rules. Such a compiler directive can also be associated with text insertion and deletion. In the evaluation, 160 variants of a triple-nested loop required for empirical performance tuning can be generated mechanically by using the high-level interface.