An Architecture- Independent CGRA Compiler enabling OpenMP Applications

Coarse-Grained reconfigurable architecture (CGRA) is a promising platform for HPC systems in the post-Moore's era. A single-source programming model is essential for practical heterogeneous computing. However, we do not have a canonical programming model and a frontend compiler for it. Existing versatile CGRAs, in respect to their execution model, computational capability, and system structure, magnify the difficulty of orchestrating the compiler techniques. It consequently forces designers of the CGRAs to develop the compiler from scratch, working only for their architectures. Such an approach is outdated, given other successful accelerators like GPU and FPGAs. This paper presents a new CGRA compiler framework in order to reduce development efforts of CG RA applications. OpenMP annotated codes are fed into the proposed compiler, as recent OpenMP support device offloading to the accelerators. This property improves the reusability of the existing source code for HPC workloads. The design of the compiler is inspired by LLVM, which is the most famous compiler framework so that the frontend is built to be architecture-independent. In this work, we demonstrate that the proposed compiler can handle different types of CG RAs without changing the source codes. In addition, we discuss the effect of architecture-independent optimization algorithms. We also provide an open-source implementation of the compiler framework at https://github.com/hal-lab-u-tokyo/CGRAOmp.