---
id: pr-flash-attention-2209
repo: Dao-AILab/flash-attention
pr: 2209
title: '[Flex][SM100] Replay expand fix on sm100'
author: drisspg
date: '2026-01-26'
url: https://github.com/Dao-AILab/flash-attention/pull/2209
source_category: upstream-code
architectures:
- sm100
tags:
- sm100
techniques: []
hardware_features:
- blackwell
kernel_types:
- attention
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: 4f892461bb6b1b7eaa917d06df620df3f6a9c2e7
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- flash_attn/cute/flash_bwd_sm100.py
- flash_attn/cute/flash_fwd_sm100.py
artifact_dir: evidence/pull-bundles/flash-attention/gh-2209
head_ref_oid: 0b0736367de2af04ae8582f247589d29d9ec2f23
---
# [Flex][SM100] Replay expand fix on sm100

- Repository: `Dao-AILab/flash-attention`
- PR: [2209](https://github.com/Dao-AILab/flash-attention/pull/2209)
- 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/flash_bwd_sm100.py`
- `flash_attn/cute/flash_fwd_sm100.py`

## Evidence Bundle

`evidence/pull-bundles/flash-attention/gh-2209`
