---
id: pr-cccl-cub-8924
repo: NVIDIA/cccl
pr: 8924
title: Fix nightly GCC8 build regressions in bit_cast and DeviceReduce
author: alliepiper
date: '2026-05-15'
url: https://github.com/NVIDIA/cccl/pull/8924
source_category: upstream-code
architectures:
- sm100
tags:
- reduction
techniques: []
hardware_features: []
kernel_types:
- reduction
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: db93bd15f30b73c5d484fbf6cacb20bca7606923
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- ci/util/build_and_test_targets.sh
- cub/cub/device/device_reduce.cuh
- libcudacxx/include/cuda/std/__algorithm/copy.h
- libcudacxx/include/cuda/std/__bit/bit_cast.h
- libcudacxx/test/libcudacxx/std/numerics/simd/simd.mask.class/ctor.pass.cpp
artifact_dir: evidence/pull-bundles/cccl-cub/gh-8924
head_ref_oid: 3242568ef8cf91cc636e2abf1e9a6f8107a7b131
---
# Fix nightly GCC8 build regressions in bit_cast and DeviceReduce

- Repository: `NVIDIA/cccl`
- PR: [8924](https://github.com/NVIDIA/cccl/pull/8924)
- 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

- `ci/util/build_and_test_targets.sh`
- `cub/cub/device/device_reduce.cuh`
- `libcudacxx/include/cuda/std/__algorithm/copy.h`
- `libcudacxx/include/cuda/std/__bit/bit_cast.h`
- `libcudacxx/test/libcudacxx/std/numerics/simd/simd.mask.class/ctor.pass.cpp`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-8924`
