---
id: pr-tensorrt-llm-13120
repo: NVIDIA/TensorRT-LLM
pr: 13120
title: '[None][bug] fix SM90 full-mask skip-softmax dispatch'
author: bobboli
date: '2026-04-18'
url: https://github.com/NVIDIA/TensorRT-LLM/pull/13120
source_category: upstream-code
architectures:
- sm90
tags:
- attention kernel
- fmha
- sm90
techniques:
- async-copy
hardware_features:
- hopper
- tma
kernel_types:
- attention
- softmax
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: b5d18e0bc2a39dd056f6906046eefeb008a2386b
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- cpp/tensorrt_llm/kernels/contextFusedMultiHeadAttention/fused_multihead_attention_v2.cpp
artifact_dir: evidence/pull-bundles/tensorrt-llm/gh-13120
head_ref_oid: 8a0286ef9adb974b07ce72f7d1b7b91bb8b1a2a6
---
# [None][bug] fix SM90 full-mask skip-softmax dispatch

- Repository: `NVIDIA/TensorRT-LLM`
- PR: [13120](https://github.com/NVIDIA/TensorRT-LLM/pull/13120)
- 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

- `cpp/tensorrt_llm/kernels/contextFusedMultiHeadAttention/fused_multihead_attention_v2.cpp`

## Evidence Bundle

`evidence/pull-bundles/tensorrt-llm/gh-13120`
