---
id: pr-cccl-cub-8125
repo: NVIDIA/cccl
pr: 8125
title: Optimized Device-to-Device Tensor Copy (cudax) - Transpose Case
author: fbusato
date: '2026-04-24'
url: https://github.com/NVIDIA/cccl/pull/8125
source_category: upstream-code
architectures:
- sm100
tags:
- memory_primitives
- transpose
techniques:
- warp-specialization
hardware_features: []
kernel_types:
- memory
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 135f0bcd971ce1f056a14bbb8f78436f196f0018
inclusion_reason: 'Transfer primitive policy carefully: coalescing, shared-memory staging, partial tiles, and determinism are part of the contract.'
changed_paths:
- cudax/include/cuda/experimental/__copy/are_mdspan_byte_copyable.cuh
- cudax/include/cuda/experimental/__copy/copy_shared_memory.cuh
- cudax/include/cuda/experimental/__copy/copy_shared_memory_utils.cuh
- cudax/include/cuda/experimental/__copy/mdspan_d2d.cuh
- cudax/include/cuda/experimental/__copy/tensor_iterator.cuh
- cudax/include/cuda/experimental/__copy_bytes/mdspan_to_raw_tensor.cuh
- cudax/include/cuda/experimental/__copy_bytes/simplify_paired.cuh
- cudax/include/cuda/experimental/__copy_bytes/tensor_query.cuh
- cudax/test/CMakeLists.txt
- cudax/test/copy/copy_nvmath_transpose.cu
- cudax/test/copy/copy_shared_memory.cu
- docs/cudax/index.rst
artifact_dir: evidence/pull-bundles/cccl-cub/gh-8125
head_ref_oid: 679ce036dd4b3bbd00ead6039cfc294bae43cff3
---
# Optimized Device-to-Device Tensor Copy (cudax) - Transpose Case

- Repository: `NVIDIA/cccl`
- PR: [8125](https://github.com/NVIDIA/cccl/pull/8125)
- Decision: `Transfer primitive policy carefully: coalescing, shared-memory staging, partial tiles, and determinism are part of the contract.`
- Reason: Transfer primitive policy carefully: coalescing, shared-memory staging, partial tiles, and determinism are part of the contract.

## Changed Paths

- `cudax/include/cuda/experimental/__copy/are_mdspan_byte_copyable.cuh`
- `cudax/include/cuda/experimental/__copy/copy_shared_memory.cuh`
- `cudax/include/cuda/experimental/__copy/copy_shared_memory_utils.cuh`
- `cudax/include/cuda/experimental/__copy/mdspan_d2d.cuh`
- `cudax/include/cuda/experimental/__copy/tensor_iterator.cuh`
- `cudax/include/cuda/experimental/__copy_bytes/mdspan_to_raw_tensor.cuh`
- `cudax/include/cuda/experimental/__copy_bytes/simplify_paired.cuh`
- `cudax/include/cuda/experimental/__copy_bytes/tensor_query.cuh`
- `cudax/test/CMakeLists.txt`
- `cudax/test/copy/copy_nvmath_transpose.cu`
- `cudax/test/copy/copy_shared_memory.cu`
- `docs/cudax/index.rst`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-8125`
