Selene: Cross-Level Barrier-Free Pipelining for Irregular Nested Loops in High-Level Synthesis [abstract] Sungwoo Yun, Seonyoung Cheon, Dongkwan Kim, Heelim Choi, Kunmo Jeong, Chan Lee, Yongwoo Lee, and Hanjun Kim To Appear: Proceedings of the 2026 International Symposium on Code Generation and Optimization (CGO), January 2026.