---
id: pr-cccl-cub-4778
repo: NVIDIA/cccl
pr: 4778
title: Align bulk copies to 16 bytes on Blackwell
author: bernhardmgruber
date: '2025-05-23'
url: https://github.com/NVIDIA/cccl/pull/4778
source_category: upstream-code
architectures:
- sm100
tags:
- blackwell
techniques: []
hardware_features:
- blackwell
kernel_types: []
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: 05fc10294583028265f78e49dde9906507a33505
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- cub/benchmarks/bench/transform/common.h
- cub/cub/device/dispatch/dispatch_transform.cuh
- cub/cub/device/dispatch/kernels/transform.cuh
- cub/cub/device/dispatch/tuning/tuning_transform.cuh
- cub/test/catch2_test_device_transform.cu
- cudax/test/containers/async_buffer/transform.cu
artifact_dir: evidence/pull-bundles/cccl-cub/gh-4778
head_ref_oid: 7ae3487d0fb8bd5b8035f086194e75400749de6b
---
# Align bulk copies to 16 bytes on Blackwell

- Repository: `NVIDIA/cccl`
- PR: [4778](https://github.com/NVIDIA/cccl/pull/4778)
- 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/benchmarks/bench/transform/common.h`
- `cub/cub/device/dispatch/dispatch_transform.cuh`
- `cub/cub/device/dispatch/kernels/transform.cuh`
- `cub/cub/device/dispatch/tuning/tuning_transform.cuh`
- `cub/test/catch2_test_device_transform.cu`
- `cudax/test/containers/async_buffer/transform.cu`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-4778`
