Stable-DiffCoder: Pushing the Frontier of Code Diffusion Large Language Model
This work addresses the longstanding performance gap between diffusion-based and autoregressive large language models for code, where diffusion models typically underperform under comparable resource constraints. Building upon the Seed-Coder architecture and dataset, the authors introduce block-wise diffusion with continuous pretraining, enhanced by a tailored warm-up strategy and a block-level truncated noise schedule to enable efficient and stable training. Under identical architectural and data conditions, this approach enables diffusion models to consistently surpass autoregressive baselines, achieving substantial improvements in structured code editing, reasoning, and low-resource language modeling. Notably, using only pretraining and supervised fine-tuning, the proposed method outperforms a range of 8B-scale autoregressive and diffusion models across multiple code benchmarks.