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Main Authors: Zou, Shun, Wang, Yong, Chen, Zehui, Chen, Lin, Tao, Chongyang, Zhao, Feng, Chu, Xiangxiang
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.08964
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author Zou, Shun
Wang, Yong
Chen, Zehui
Chen, Lin
Tao, Chongyang
Zhao, Feng
Chu, Xiangxiang
author_facet Zou, Shun
Wang, Yong
Chen, Zehui
Chen, Lin
Tao, Chongyang
Zhao, Feng
Chu, Xiangxiang
contents Diffusion Large Language Models (dLLMs) have recently become a promising alternative to autoregressive large language models (ARMs). Semi-autoregressive (Semi-AR) decoding is widely employed in base dLLMs and advanced decoding strategies due to its superior performance. However, our observations reveal that Semi-AR decoding suffers from inherent block constraints, which cause the decoding of many cross-block stable tokens to be unnecessarily delayed. To address this challenge, we systematically investigate the identification of stable tokens and present three key findings: (1) naive lookahead decoding is unreliable, (2) token stability closely correlates with convergence trend, and (3) historical information is isolated. Building on these insights, we propose Anchor-based History-stable Decoding (AHD), a training-free, plug-and-play dynamic decoding strategy. Specifically, AHD monitors the stability trend of tokens in real time through dynamic anchors. Once a token reaches stability, it initiates early cross-block decoding to enhance efficiency and performance. Extensive experiments across language, vision-language, and audio-language domains demonstrate that AHD simultaneously improves both performance and inference efficiency. Notably, AHD effectively reverses the performance degradation typically observed in existing advanced decoding acceleration strategies. For instance, on the BBH benchmark, our approach reduces decoding steps by 80% while improving performance by 3.67%.
format Preprint
id arxiv_https___arxiv_org_abs_2604_08964
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Breaking Block Boundaries: Anchor-based History-stable Decoding for Diffusion Large Language Models
Zou, Shun
Wang, Yong
Chen, Zehui
Chen, Lin
Tao, Chongyang
Zhao, Feng
Chu, Xiangxiang
Computation and Language
Diffusion Large Language Models (dLLMs) have recently become a promising alternative to autoregressive large language models (ARMs). Semi-autoregressive (Semi-AR) decoding is widely employed in base dLLMs and advanced decoding strategies due to its superior performance. However, our observations reveal that Semi-AR decoding suffers from inherent block constraints, which cause the decoding of many cross-block stable tokens to be unnecessarily delayed. To address this challenge, we systematically investigate the identification of stable tokens and present three key findings: (1) naive lookahead decoding is unreliable, (2) token stability closely correlates with convergence trend, and (3) historical information is isolated. Building on these insights, we propose Anchor-based History-stable Decoding (AHD), a training-free, plug-and-play dynamic decoding strategy. Specifically, AHD monitors the stability trend of tokens in real time through dynamic anchors. Once a token reaches stability, it initiates early cross-block decoding to enhance efficiency and performance. Extensive experiments across language, vision-language, and audio-language domains demonstrate that AHD simultaneously improves both performance and inference efficiency. Notably, AHD effectively reverses the performance degradation typically observed in existing advanced decoding acceleration strategies. For instance, on the BBH benchmark, our approach reduces decoding steps by 80% while improving performance by 3.67%.
title Breaking Block Boundaries: Anchor-based History-stable Decoding for Diffusion Large Language Models
topic Computation and Language
url https://arxiv.org/abs/2604.08964