---
id: pr-cccl-cub-6814
repo: NVIDIA/cccl
pr: 6814
title: Improve our `WarpReduce` implementation
author: miscco
date: '2025-12-01'
url: https://github.com/NVIDIA/cccl/pull/6814
source_category: upstream-code
architectures:
- sm90
tags:
- sm90
techniques:
- warp-specialization
hardware_features:
- hopper
kernel_types: []
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: bbe5cb7e406426ea6b5a0daf4e979851c2436fb5
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- cub/cub/warp/specializations/warp_reduce_shfl.cuh
artifact_dir: evidence/pull-bundles/cccl-cub/gh-6814
head_ref_oid: 9479fc0cca1eae736e624b77fee0880e80f4161b
---
# Improve our `WarpReduce` implementation

- Repository: `NVIDIA/cccl`
- PR: [6814](https://github.com/NVIDIA/cccl/pull/6814)
- 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

- `cub/cub/warp/specializations/warp_reduce_shfl.cuh`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-6814`
