[INFRA] Import NVIDIA/CCCL upstream as optimization reference library

CCCL (CUDA C++ Core Libraries) provides:
- CUB: device/block/warp-level GPU primitives (reduce, scan, sort, topk)
- Thrust: high-level parallel algorithms (transform_reduce, sort, scan)
- libcudacxx: CUDA C++ standard library (atomics, barriers, memory)
- cudax: experimental features (memory resources, allocators)
- Tuning policies: per-SM hardware-specific algorithm parameters

Competition optimization vectors mapped to CCCL:
- Output TPS (83% weight): warp_reduce, block_reduce, device_topk
- Input TPS (14% weight): device_scan, block_load, prefetch
- Cache TPS (3% weight): prefix caching strategy patterns
- Memory (0.9 util): pooled/cached/buddy allocators

Source: https://github.com/NVIDIA/cccl (shallow clone, HEAD only)
License: Apache-2.0

cccl_upstream/libcudacxx/test/support/hierarchy_queries.h

@@ -0,0 +1,132 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the libcu++ Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+// SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SUPPORT_HIERARCHY_QUERIES_H
+#define SUPPORT_HIERARCHY_QUERIES_H
+
+#include <cuda/hierarchy>
+#include <cuda/std/cassert>
+#include <cuda/std/cstddef>
+#include <cuda/std/mdspan>
+
+#include "test_macros.h"
+
+template <class T, class Vec>
+TEST_DEVICE_FUNC void test_result(cuda::hierarchy_query_result<T> res, Vec exp)
+{
+  assert(res.x == static_cast<T>(exp.x));
+  assert(res.y == static_cast<T>(exp.y));
+  assert(res.z == static_cast<T>(exp.z));
+}
+
+template <class IRes, class IExp, cuda::std::size_t... Exts>
+TEST_DEVICE_FUNC void test_result(cuda::std::extents<IRes, Exts...> res, cuda::std::extents<IExp, Exts...> exp)
+{
+  for (cuda::std::size_t i = 0; i < sizeof...(Exts); ++i)
+  {
+    assert(res.extent(i) == static_cast<IRes>(exp.extent(i)));
+  }
+}
+
+template <class Level, class... Args>
+TEST_DEVICE_FUNC void test_dims(const uint3 exp, const Level& level, Args... args)
+{
+  test_result(level.dims(args...), exp);
+  test_result(level.template dims_as<short>(args...), exp);
+  test_result(level.template dims_as<int>(args...), exp);
+  test_result(level.template dims_as<long long>(args...), exp);
+  test_result(level.template dims_as<unsigned short>(args...), exp);
+  test_result(level.template dims_as<unsigned int>(args...), exp);
+  test_result(level.template dims_as<unsigned long long>(args...), exp);
+}
+
+template <class Level, class... Args>
+TEST_DEVICE_FUNC void test_static_dims(const ulonglong3 exp, Level level, Args... args)
+{
+  static_assert(level.static_dims(args...).x != 0);
+  test_result(level.static_dims(args...), exp);
+}
+
+template <class Exp, class Level, class... Args>
+TEST_DEVICE_FUNC void test_extents(const Exp exp, const Level& level, Args... args)
+{
+  test_result(level.extents(args...), exp);
+  test_result(level.template extents_as<short>(args...), exp);
+  test_result(level.template extents_as<int>(args...), exp);
+  test_result(level.template extents_as<long long>(args...), exp);
+  test_result(level.template extents_as<unsigned short>(args...), exp);
+  test_result(level.template extents_as<unsigned int>(args...), exp);
+  test_result(level.template extents_as<unsigned long long>(args...), exp);
+}
+
+template <class Level, class... Args>
+TEST_DEVICE_FUNC void test_static_count(Level level, Args... args)
+{
+  constexpr auto static_dims = level.static_dims(args...);
+  if constexpr (static_dims.x != cuda::std::dynamic_extent && static_dims.y != cuda::std::dynamic_extent
+                && static_dims.z != cuda::std::dynamic_extent)
+  {
+    static_assert(level.static_count(args...) == static_dims.x * static_dims.y * static_dims.z);
+  }
+  else
+  {
+    static_assert(level.static_count(args...) == cuda::std::dynamic_extent);
+  }
+}
+
+template <class Level, class... Args>
+TEST_DEVICE_FUNC void test_count(const cuda::std::size_t exp, const Level& level, Args... args)
+{
+  assert(level.count(args...) == exp);
+  assert(level.template count_as<short>(args...) == static_cast<short>(exp));
+  assert(level.template count_as<int>(args...) == static_cast<int>(exp));
+  assert(level.template count_as<long long>(args...) == static_cast<long long>(exp));
+  assert(level.template count_as<unsigned short>(args...) == static_cast<unsigned short>(exp));
+  assert(level.template count_as<unsigned int>(args...) == static_cast<unsigned int>(exp));
+  assert(level.template count_as<unsigned long long>(args...) == static_cast<unsigned long long>(exp));
+}
+
+template <class Level, class... Args>
+TEST_DEVICE_FUNC void test_index(const uint3 exp, const Level& level, Args... args)
+{
+  test_result(level.index(args...), exp);
+  test_result(level.template index_as<short>(args...), exp);
+  test_result(level.template index_as<int>(args...), exp);
+  test_result(level.template index_as<long long>(args...), exp);
+  test_result(level.template index_as<unsigned short>(args...), exp);
+  test_result(level.template index_as<unsigned int>(args...), exp);
+  test_result(level.template index_as<unsigned long long>(args...), exp);
+}
+
+template <class Level, class... Args>
+TEST_DEVICE_FUNC void test_rank(const cuda::std::size_t exp, const Level& level, Args... args)
+{
+  assert(level.rank(args...) == exp);
+  assert(level.template rank_as<short>(args...) == static_cast<short>(exp));
+  assert(level.template rank_as<int>(args...) == static_cast<int>(exp));
+  assert(level.template rank_as<long long>(args...) == static_cast<long long>(exp));
+  assert(level.template rank_as<unsigned short>(args...) == static_cast<unsigned short>(exp));
+  assert(level.template rank_as<unsigned int>(args...) == static_cast<unsigned int>(exp));
+  assert(level.template rank_as<unsigned long long>(args...) == static_cast<unsigned long long>(exp));
+}
+
+template <class... Args>
+TEST_DEVICE_FUNC constexpr cuda::std::size_t mul_static_extents(Args... args)
+{
+  if (((args == cuda::std::dynamic_extent) || ...))
+  {
+    return cuda::std::dynamic_extent;
+  }
+  else
+  {
+    return (cuda::std::size_t{1} * ... * args);
+  }
+}
+
+#endif // SUPPORT_HIERARCHY_QUERIES_H