The performance of the code generated by a compiler depends on the order in which the optimization passes are applied. In high-level synthesis, the quality of the generated circuit relates directly to the code generated by the front-end compiler. Choosing a good order--often referred to as the phase-ordering problem--is an NP-hard problem. In this paper, we evaluate a new technique to address the phase-ordering problem: deep reinforcement learning. We implement a framework in the context of the LLVM compiler to optimize the ordering for HLS programs and compare the performance of deep reinforcement learning to state-of-the-art algorithms that address the phase-ordering problem. Overall, our framework runs one to two orders of magnitude faster than these algorithms, and achieves a 16% improvement in circuit performance over the -O3 compiler flag.
@article{arxiv.1901.04615,
title = {AutoPhase: Compiler Phase-Ordering for High Level Synthesis with Deep Reinforcement Learning},
author = {Ameer Haj-Ali and Qijing Huang and William Moses and John Xiang and Ion Stoica and Krste Asanovic and John Wawrzynek},
journal= {arXiv preprint arXiv:1901.04615},
year = {2019}
}