In March 2025, Seliopoulos contributed to the oxcaml/oxcaml repository by delivering a targeted performance improvement in the register allocator. He refactored the range handling logic using a Cursor API, focusing on the hot path for range overlap and liveness checks. This approach eliminated intermediate cell allocations in the doubly linked list, directly reducing memory allocation churn and improving garbage collection efficiency during the allocation phase. Working primarily in OCaml and leveraging expertise in compiler development and low-level optimization, Seliopoulos addressed a core efficiency bottleneck, demonstrating depth in both data structure design and runtime performance engineering.