Leveraging MLIR for Efficient Irregular-Shaped CGRA Overlay Design: (PhD Forum Paper)

Coarse-grained reconfigurable arrays (CGRAs) are reconfigurable architectures that combine the efficiency of custom datapaths with the flexibility of FPGAs. Optimized word-level functional units with reconfigurable interconnect enable a wide range of applications. Due to the irregular data movement patterns and the diversity of real-world HPC applications, a traditional homogeneous regular-shaped CGRA architecture can be sub-optimal. A more application-specific arrangement of resources could, however, result in poor hardware reuse and increased deployment effort for a CGRA. Using CGRA overlays can increase hardware reuse while maintaining high performance of a more optimized architecture. This proposal uses and builds upon the built-in tools of the MLIR infrastructure to target a class of applications that can be analyzed, rewritten, and optimized based on the available resources of an underlying CGRA architecture, thereby better exploiting hardware resources.