This paper proposes ISDC, a novel feedback-guided iterative system of difference constraints (SDC) scheduling algorithm for high-level synthesis (HLS). ISDC leverages subgraph extraction-based low-level feedback from downstream tools like logic synthesizers to iteratively refine HLS scheduling. Technical innovations include: (1) An enhanced SDC formulation that effectively integrates low-level feedback into the linear-programming (LP) problem; (2) A fanout and window-based subgraph extraction mechanism driving the feedback cycle; (3) A no-human-in-loop ISDC flow compatible with a wide range of downstream tools and process design kits (PDKs). Evaluation shows that ISDC reduces register usage by 28.5% against an industrial-strength open-source HLS tool.

翻译：本文提出ISDC，一种新颖的反馈引导式迭代差分约束系统（SDC）调度算法，用于高层次综合（HLS）。ISDC利用基于子图提取的底层反馈（来自逻辑综合器等下游工具），以迭代方式优化HLS调度。技术创新包括：（1）增强的SDC公式，可有效将底层反馈集成到线性规划（LP）问题中；（2）基于扇出和窗口的子图提取机制，驱动反馈循环；（3）无人工干预的ISDC流程，兼容各类下游工具和工艺设计套件（PDK）。评估结果表明，与工业级开源HLS工具相比，ISDC可减少28.5%的寄存器使用量。