---
id: pr-cccl-cub-4976
repo: NVIDIA/cccl
pr: 4976
title: Replace `cg::memcpy_async` in `memcpy_async` transform kernel by custom implementation
author: bernhardmgruber
date: '2025-06-25'
url: https://github.com/NVIDIA/cccl/pull/4976
source_category: upstream-code
architectures:
- sm100
tags:
- cooperative-groups
techniques: []
hardware_features: []
kernel_types: []
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: f4f45d57a0bb1c7a94d32284221fa0b1b93a119a
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- 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
artifact_dir: evidence/pull-bundles/cccl-cub/gh-4976
head_ref_oid: 9d6a1c3d5390fc5e123bb940e2ba30e3cbf5fdcc
---
# Replace `cg::memcpy_async` in `memcpy_async` transform kernel by custom implementation

- Repository: `NVIDIA/cccl`
- PR: [4976](https://github.com/NVIDIA/cccl/pull/4976)
- 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/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`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-4976`
