---
id: pr-cccl-cub-8394
repo: NVIDIA/cccl
pr: 8394
title: Refactor and improve `extents_as` queries
author: davebayer
date: '2026-04-14'
url: https://github.com/NVIDIA/cccl/pull/8394
source_category: upstream-code
architectures:
- sm100
tags:
- warp
techniques:
- warp-specialization
hardware_features: []
kernel_types: []
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: a0a7ac1994911cc2ed7e4f89543868a791e229ae
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- cudax/include/cuda/experimental/__hierarchy/synchronizers.cuh
- cudax/include/cuda/experimental/__hierarchy/this_group.cuh
- libcudacxx/include/cuda/__fwd/hierarchy.h
- libcudacxx/include/cuda/__hierarchy/block_level.h
- libcudacxx/include/cuda/__hierarchy/cluster_level.h
- libcudacxx/include/cuda/__hierarchy/hierarchy_level_base.h
- libcudacxx/include/cuda/__hierarchy/native_hierarchy_level_base.h
- libcudacxx/include/cuda/__hierarchy/queries/extents.h
- libcudacxx/include/cuda/__hierarchy/thread_level.h
- libcudacxx/include/cuda/__hierarchy/warp_level.h
- libcudacxx/include/cuda/hierarchy
- libcudacxx/test/libcudacxx/cuda/hierarchy/block_level/hierarchy_queries.pass.cpp
- libcudacxx/test/libcudacxx/cuda/hierarchy/block_level/hierarchy_query_signatures.compile.pass.cpp
- libcudacxx/test/libcudacxx/cuda/hierarchy/cluster_level/hierarchy_queries.pass.cpp
- libcudacxx/test/libcudacxx/cuda/hierarchy/cluster_level/hierarchy_query_signatures.compile.pass.cpp
- libcudacxx/test/libcudacxx/cuda/hierarchy/hierarchy_objects.compile.pass.cpp
- libcudacxx/test/libcudacxx/cuda/hierarchy/thread_level/hierarchy_queries.pass.cpp
- libcudacxx/test/libcudacxx/cuda/hierarchy/thread_level/hierarchy_query_signatures.compile.pass.cpp
- libcudacxx/test/libcudacxx/cuda/hierarchy/warp_level/hierarchy_queries.pass.cpp
- libcudacxx/test/libcudacxx/cuda/hierarchy/warp_level/hierarchy_query_signatures.compile.pass.cpp
artifact_dir: evidence/pull-bundles/cccl-cub/gh-8394
head_ref_oid: 7ff509b672d09a5414bed982da20dd039fd6bc22
---
# Refactor and improve `extents_as` queries

- Repository: `NVIDIA/cccl`
- PR: [8394](https://github.com/NVIDIA/cccl/pull/8394)
- 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

- `cudax/include/cuda/experimental/__hierarchy/synchronizers.cuh`
- `cudax/include/cuda/experimental/__hierarchy/this_group.cuh`
- `libcudacxx/include/cuda/__fwd/hierarchy.h`
- `libcudacxx/include/cuda/__hierarchy/block_level.h`
- `libcudacxx/include/cuda/__hierarchy/cluster_level.h`
- `libcudacxx/include/cuda/__hierarchy/hierarchy_level_base.h`
- `libcudacxx/include/cuda/__hierarchy/native_hierarchy_level_base.h`
- `libcudacxx/include/cuda/__hierarchy/queries/extents.h`
- `libcudacxx/include/cuda/__hierarchy/thread_level.h`
- `libcudacxx/include/cuda/__hierarchy/warp_level.h`
- `libcudacxx/include/cuda/hierarchy`
- `libcudacxx/test/libcudacxx/cuda/hierarchy/block_level/hierarchy_queries.pass.cpp`
- `libcudacxx/test/libcudacxx/cuda/hierarchy/block_level/hierarchy_query_signatures.compile.pass.cpp`
- `libcudacxx/test/libcudacxx/cuda/hierarchy/cluster_level/hierarchy_queries.pass.cpp`
- `libcudacxx/test/libcudacxx/cuda/hierarchy/cluster_level/hierarchy_query_signatures.compile.pass.cpp`
- `libcudacxx/test/libcudacxx/cuda/hierarchy/hierarchy_objects.compile.pass.cpp`
- `libcudacxx/test/libcudacxx/cuda/hierarchy/thread_level/hierarchy_queries.pass.cpp`
- `libcudacxx/test/libcudacxx/cuda/hierarchy/thread_level/hierarchy_query_signatures.compile.pass.cpp`
- `libcudacxx/test/libcudacxx/cuda/hierarchy/warp_level/hierarchy_queries.pass.cpp`
- `libcudacxx/test/libcudacxx/cuda/hierarchy/warp_level/hierarchy_query_signatures.compile.pass.cpp`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-8394`
