---
id: pr-flash-attention-2563
repo: Dao-AILab/flash-attention
pr: 2563
title: '[Cute, flex, sm90] fix sm90 flex'
author: geruome
date: '2026-05-13'
url: https://github.com/Dao-AILab/flash-attention/pull/2563
source_category: upstream-code
architectures:
- sm90
tags:
- attention
- attention kernel
- cuda kernel
- cute
- sm90
- triton kernel
techniques: []
hardware_features:
- hopper
kernel_types:
- attention
languages:
- cuda-cpp
- cute-dsl
- triton
captured_at: '2026-05-16'
status: merged
merge_sha: 9cee95fd92ab49f585b57ad49bec5e4d67b5150c
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- flash_attn/cute/flash_fwd_sm90.py
artifact_dir: evidence/pull-bundles/flash-attention/gh-2563
head_ref_oid: 90b2f638d9929a1bd676a84e97dca4b7ec3806b5
---
# [Cute, flex, sm90] fix sm90 flex

- Repository: `Dao-AILab/flash-attention`
- PR: [2563](https://github.com/Dao-AILab/flash-attention/pull/2563)
- 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_fwd_sm90.py`

## Evidence Bundle

`evidence/pull-bundles/flash-attention/gh-2563`
