---
id: pr-cccl-cub-6811
repo: NVIDIA/cccl
pr: 6811
title: Integrate decoupled lookahead warpspeed scan
author: bernhardmgruber
date: '2026-02-10'
url: https://github.com/NVIDIA/cccl/pull/6811
source_category: upstream-code
architectures:
- sm100
- sm90
tags:
- arch_pipeline
- memory_primitives
- scan
- scheduler_autotune
- sm100
- sm90
- warp reduce
- warpspeed scan
techniques:
- autotuning
- pipeline-stages
- tile-scheduling
- warp-specialization
hardware_features:
- blackwell
- hopper
kernel_types:
- memory
- reduction
- runtime
- scan
- scheduler
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 94bd6e40d36a765a9bc6db69a60619092b41e228
inclusion_reason: 'Transfer primitive policy carefully: coalescing, shared-memory staging, partial tiles, and determinism are part of the contract.'
changed_paths:
- c/parallel/src/scan.cu
- cub/cub/detail/launcher/cuda_runtime.cuh
- cub/cub/detail/warpspeed/allocators/smem_allocator.cuh
- cub/cub/detail/warpspeed/constant_assert.cuh
- cub/cub/detail/warpspeed/look_ahead.cuh
- cub/cub/detail/warpspeed/make_warp_uniform.cuh
- cub/cub/detail/warpspeed/optimize_smem_ptr.cuh
- cub/cub/detail/warpspeed/resource/smem_phase.cuh
- cub/cub/detail/warpspeed/resource/smem_ref.cuh
- cub/cub/detail/warpspeed/resource/smem_resource.cuh
- cub/cub/detail/warpspeed/resource/smem_resource_raw.cuh
- cub/cub/detail/warpspeed/resource/smem_stage.cuh
- cub/cub/detail/warpspeed/special_registers.cuh
- cub/cub/detail/warpspeed/squad/load_store.cuh
- cub/cub/detail/warpspeed/squad/squad.cuh
- cub/cub/detail/warpspeed/squad/squad_desc.cuh
- cub/test/catch2_test_device_scan.cu
- libcudacxx/include/cuda/std/__cccl/visibility.h
artifact_dir: evidence/pull-bundles/cccl-cub/gh-6811
head_ref_oid: d20a2724816ebda7ee9d12a26900394327a539b7
---
# Integrate decoupled lookahead warpspeed scan

- Repository: `NVIDIA/cccl`
- PR: [6811](https://github.com/NVIDIA/cccl/pull/6811)
- 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

- `c/parallel/src/scan.cu`
- `cub/cub/detail/launcher/cuda_runtime.cuh`
- `cub/cub/detail/warpspeed/allocators/smem_allocator.cuh`
- `cub/cub/detail/warpspeed/constant_assert.cuh`
- `cub/cub/detail/warpspeed/look_ahead.cuh`
- `cub/cub/detail/warpspeed/make_warp_uniform.cuh`
- `cub/cub/detail/warpspeed/optimize_smem_ptr.cuh`
- `cub/cub/detail/warpspeed/resource/smem_phase.cuh`
- `cub/cub/detail/warpspeed/resource/smem_ref.cuh`
- `cub/cub/detail/warpspeed/resource/smem_resource.cuh`
- `cub/cub/detail/warpspeed/resource/smem_resource_raw.cuh`
- `cub/cub/detail/warpspeed/resource/smem_stage.cuh`
- `cub/cub/detail/warpspeed/special_registers.cuh`
- `cub/cub/detail/warpspeed/squad/load_store.cuh`
- `cub/cub/detail/warpspeed/squad/squad.cuh`
- `cub/cub/detail/warpspeed/squad/squad_desc.cuh`
- `cub/test/catch2_test_device_scan.cu`
- `libcudacxx/include/cuda/std/__cccl/visibility.h`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-6811`
