Survival-Guided Length Control for Efficient Diffusion Language Models

Ivan Kobyzev, Abbas Ghaddar, Yufei Cui


Abstract
Diffusion language models (DLMs) generate text by iteratively denoising masked sequences, but standard decoding either fixes the sequence length or relies on ad hoc stopping rules, often leading to unnecessary denoising steps. We recast length selection as a discrete-time survival problem over the end-of-sequence token and propose a plug-in, training-free length predictor that can be added to any existing DLM. Across reasoning and code-generation benchmarks, survival-guided length decoding speeds up inference by up to 7× while preserving task accuracy. We further find that predicted lengths vary widely even within the same dataset, making model performance sensitive to the chosen length.
Anthology ID:
2026.emnlp-main.17
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
391–399
Language:
URL:
https://aclanthology.org/2026.emnlp-main.17/
DOI:
Bibkey:
Cite (ACL):
Ivan Kobyzev, Abbas Ghaddar, and Yufei Cui. 2026. Survival-Guided Length Control for Efficient Diffusion Language Models. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 391–399, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Survival-Guided Length Control for Efficient Diffusion Language Models (Kobyzev et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.17.pdf