---
id: pr-flash-attention-1984
repo: Dao-AILab/flash-attention
pr: 1984
title: '[Cute] Extract block-sparse utilities from SM80/90'
author: drisspg
date: '2025-11-05'
url: https://github.com/Dao-AILab/flash-attention/pull/1984
source_category: upstream-code
architectures:
- sm100
tags:
- sm80
techniques: []
hardware_features: []
kernel_types:
- attention
languages:
- cute-dsl
captured_at: '2026-05-16'
status: merged
merge_sha: ad70a007e6287d4f7e766f94bcf2f9a813f20f6b
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- flash_attn/cute/block_sparse_utils.py
- flash_attn/cute/block_sparsity.py
- flash_attn/cute/flash_fwd.py
artifact_dir: evidence/pull-bundles/flash-attention/gh-1984
head_ref_oid: b9bbcbf0e6b29ccf6a5d6a4dd5f148dce8ada537
---
# [Cute] Extract block-sparse utilities from SM80/90

- Repository: `Dao-AILab/flash-attention`
- PR: [1984](https://github.com/Dao-AILab/flash-attention/pull/1984)
- Decision: `Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.`
- Reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.

## Changed Paths

- `flash_attn/cute/block_sparse_utils.py`
- `flash_attn/cute/block_sparsity.py`
- `flash_attn/cute/flash_fwd.py`

## Evidence Bundle

`evidence/pull-bundles/flash-attention/gh-1984`
