Traditional compilers operate on a single generic intermediate representation (IR). These IRs are usually low-level and close to machine instructions. As a result, optimizations relying on domain-specific information are either not possible or require complex analysis to recover the missing information. In contrast, multi-level rewriting instantiates a hierarchy of dialects (IRs), lowers programs level-by-level, and performs code transformations at the most suitable level. We demonstrate the effectiveness of this approach for the weather and climate domain. In particular, we develop a prototype compiler and design stencil- and GPU-specific dialects based on a set of newly introduced design principles. We find that two domain-specific optimizations (500 lines of code) realized on top of LLVM's extensible MLIR compiler infrastructure suffice to outperform state-of-the-art solutions. In essence, multi-level rewriting promises to herald the age of specialized compilers composed from domain- and target-specific dialects implemented on top of a shared infrastructure.
@article{arxiv.2005.13014,
title = {Domain-Specific Multi-Level IR Rewriting for GPU},
author = {Tobias Gysi and Christoph Müller and Oleksandr Zinenko and Stephan Herhut and Eddie Davis and Tobias Wicky and Oliver Fuhrer and Torsten Hoefler and Tobias Grosser},
journal= {arXiv preprint arXiv:2005.13014},
year = {2020}
}