[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/thrust/testing/address_stability.cu

@@ -0,0 +1,120 @@
+#include <cuda/__functional/address_stability.h>
+
+#include <unittest/unittest.h>
+
+struct addable
+{
+  _CCCL_HOST_DEVICE friend auto operator+(const addable&, const addable&) -> addable
+  {
+    return addable{};
+  }
+};
+
+void TestAddressStabilityLibcuxx()
+{
+  using ::cuda::proclaim_copyable_arguments;
+  using ::cuda::proclaims_copyable_arguments;
+
+  // libcu++ function objects with known types
+  static_assert(proclaims_copyable_arguments<::cuda::std::plus<int>>::value);
+  static_assert(!proclaims_copyable_arguments<::cuda::std::plus<>>::value);
+
+  // libcu++ function objects with unknown types
+  static_assert(!proclaims_copyable_arguments<::cuda::std::plus<addable>>::value);
+  static_assert(!proclaims_copyable_arguments<::cuda::std::plus<>>::value);
+
+  // libcu++ function objects with unknown types and opt-in
+  static_assert(proclaims_copyable_arguments<decltype(proclaim_copyable_arguments(cuda::std::plus<addable>{}))>::value);
+  static_assert(proclaims_copyable_arguments<decltype(proclaim_copyable_arguments(cuda::std::plus<>{}))>::value);
+}
+DECLARE_UNITTEST(TestAddressStabilityLibcuxx);
+
+void TestAddressStabilityThrust()
+{
+  using ::cuda::proclaim_copyable_arguments;
+  using ::cuda::proclaims_copyable_arguments;
+
+  // thrust function objects with known types
+  static_assert(proclaims_copyable_arguments<::cuda::std::plus<int>>::value);
+  static_assert(!proclaims_copyable_arguments<::cuda::std::plus<>>::value);
+
+  // thrust function objects with unknown types
+  static_assert(!proclaims_copyable_arguments<::cuda::std::plus<addable>>::value);
+  static_assert(!proclaims_copyable_arguments<::cuda::std::plus<>>::value);
+
+  // thrust function objects with unknown types and opt-in
+  static_assert(
+    proclaims_copyable_arguments<decltype(proclaim_copyable_arguments(::cuda::std::plus<addable>{}))>::value);
+  static_assert(proclaims_copyable_arguments<decltype(proclaim_copyable_arguments(::cuda::std::plus<>{}))>::value);
+}
+DECLARE_UNITTEST(TestAddressStabilityThrust);
+
+template <typename T>
+struct my_plus
+{
+  _CCCL_HOST_DEVICE auto operator()(T a, T b) const -> T
+  {
+    return a + b;
+  }
+};
+
+void TestAddressStabilityUserDefinedFunctionObject()
+{
+  using ::cuda::proclaim_copyable_arguments;
+  using ::cuda::proclaims_copyable_arguments;
+
+  // by-value overload
+  static_assert(!proclaims_copyable_arguments<my_plus<int>>::value);
+
+  // by-value overload with opt-in
+  static_assert(proclaims_copyable_arguments<decltype(proclaim_copyable_arguments(my_plus<int>{}))>::value);
+
+  // by-reference overload
+  static_assert(!proclaims_copyable_arguments<my_plus<int&>>::value);
+  static_assert(!proclaims_copyable_arguments<my_plus<const int&>>::value);
+  static_assert(!proclaims_copyable_arguments<my_plus<int&&>>::value);
+  static_assert(!proclaims_copyable_arguments<my_plus<const int&&>>::value);
+
+  // by-reference overload with opt-in
+  static_assert(proclaims_copyable_arguments<decltype(proclaim_copyable_arguments(my_plus<int&>{}))>::value);
+  static_assert(proclaims_copyable_arguments<decltype(proclaim_copyable_arguments(my_plus<const int&>{}))>::value);
+  static_assert(proclaims_copyable_arguments<decltype(proclaim_copyable_arguments(my_plus<int&&>{}))>::value);
+  static_assert(proclaims_copyable_arguments<decltype(proclaim_copyable_arguments(my_plus<const int&&>{}))>::value);
+}
+DECLARE_UNITTEST(TestAddressStabilityUserDefinedFunctionObject);
+
+void TestAddressStabilityLambda()
+{
+  using ::cuda::proclaim_copyable_arguments;
+  using ::cuda::proclaims_copyable_arguments;
+
+  {
+    auto l = [](const int& i) {
+      return i + 2;
+    };
+    static_assert(!proclaims_copyable_arguments<decltype(l)>::value);
+    auto pr_l = proclaim_copyable_arguments(l);
+    ASSERT_EQUAL(pr_l(3), 5);
+    static_assert(proclaims_copyable_arguments<decltype(pr_l)>::value);
+  }
+
+  {
+    auto l = [] _CCCL_DEVICE(const int& i) {
+      return i + 2;
+    };
+    static_assert(!proclaims_copyable_arguments<decltype(l)>::value);
+    [[maybe_unused]] auto pr_device_l = proclaim_copyable_arguments(l);
+    static_assert(proclaims_copyable_arguments<decltype(pr_device_l)>::value);
+  }
+
+  {
+    auto l = [] _CCCL_HOST_DEVICE(const int& i) {
+      return i + 2;
+    };
+    static_assert(!proclaims_copyable_arguments<decltype(l)>::value);
+    auto pr_l = proclaim_copyable_arguments(l);
+    ASSERT_EQUAL(pr_l(3), 5);
+    static_assert(proclaims_copyable_arguments<decltype(pr_l)>::value);
+  }
+}
+DECLARE_UNITTEST(TestAddressStabilityLambda);