---
id: pr-cccl-cub-4716
repo: NVIDIA/cccl
pr: 4716
title: Split Optimize Warp Reduce PR - CUB part
author: fbusato
date: '2025-05-20'
url: https://github.com/NVIDIA/cccl/pull/4716
source_category: upstream-code
architectures:
- sm100
tags:
- memory_primitives
- warp reduce
techniques:
- warp-specialization
hardware_features: []
kernel_types:
- memory
- sort
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 14428a105d2d331e5c171aca24a6a0453e5bb5a4
inclusion_reason: 'Transfer primitive policy carefully: coalescing, shared-memory staging, partial tiles, and determinism are part of the contract.'
changed_paths:
- cub/cub/block/radix_rank_sort_operations.cuh
- cub/cub/detail/array_utils.cuh
- cub/cub/detail/type_traits.cuh
- cub/cub/detail/unsafe_bitcast.cuh
- cub/cub/device/dispatch/dispatch_adjacent_difference.cuh
- cub/cub/device/dispatch/dispatch_reduce.cuh
- cub/cub/thread/thread_operators.cuh
- cub/cub/thread/thread_reduce.cuh
artifact_dir: evidence/pull-bundles/cccl-cub/gh-4716
head_ref_oid: 4f4062a1c3264b68aad5781e9674c68facc0b6bb
---
# Split Optimize Warp Reduce PR - CUB part

- Repository: `NVIDIA/cccl`
- PR: [4716](https://github.com/NVIDIA/cccl/pull/4716)
- 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

- `cub/cub/block/radix_rank_sort_operations.cuh`
- `cub/cub/detail/array_utils.cuh`
- `cub/cub/detail/type_traits.cuh`
- `cub/cub/detail/unsafe_bitcast.cuh`
- `cub/cub/device/dispatch/dispatch_adjacent_difference.cuh`
- `cub/cub/device/dispatch/dispatch_reduce.cuh`
- `cub/cub/thread/thread_operators.cuh`
- `cub/cub/thread/thread_reduce.cuh`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-4716`
