[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/cuda/generate.cu

@@ -0,0 +1,152 @@
+#include <thrust/execution_policy.h>
+#include <thrust/generate.h>
+
+#include <unittest/unittest.h>
+
+template <typename T>
+struct return_value
+{
+  T val;
+
+  return_value() = default;
+  return_value(T v)
+      : val(v)
+  {}
+
+  _CCCL_HOST_DEVICE T operator()()
+  {
+    return val;
+  }
+};
+
+#ifdef THRUST_TEST_DEVICE_SIDE
+template <typename ExecutionPolicy, typename Iterator, typename Function>
+__global__ void generate_kernel(ExecutionPolicy exec, Iterator first, Iterator last, Function f)
+{
+  thrust::generate(exec, first, last, f);
+}
+
+template <typename T, typename ExecutionPolicy>
+void TestGenerateDevice(ExecutionPolicy exec, const size_t n)
+{
+  thrust::host_vector<T> h_result(n);
+  thrust::device_vector<T> d_result(n);
+
+  T value = 13;
+  return_value<T> f(value);
+
+  thrust::generate(h_result.begin(), h_result.end(), f);
+
+  generate_kernel<<<1, 1>>>(exec, d_result.begin(), d_result.end(), f);
+  {
+    cudaError_t const err = cudaDeviceSynchronize();
+    ASSERT_EQUAL(cudaSuccess, err);
+  }
+
+  ASSERT_EQUAL(h_result, d_result);
+}
+
+template <typename T>
+void TestGenerateDeviceSeq(const size_t n)
+{
+  TestGenerateDevice<T>(thrust::seq, n);
+}
+DECLARE_VARIABLE_UNITTEST(TestGenerateDeviceSeq);
+
+template <typename T>
+void TestGenerateDeviceDevice(const size_t n)
+{
+  TestGenerateDevice<T>(thrust::device, n);
+}
+DECLARE_VARIABLE_UNITTEST(TestGenerateDeviceDevice);
+#endif
+
+void TestGenerateCudaStreams()
+{
+  thrust::device_vector<int> result(5);
+
+  int value = 13;
+
+  return_value<int> f(value);
+
+  cudaStream_t s;
+  cudaStreamCreate(&s);
+
+  thrust::generate(thrust::cuda::par.on(s), result.begin(), result.end(), f);
+  cudaStreamSynchronize(s);
+
+  ASSERT_EQUAL(result[0], value);
+  ASSERT_EQUAL(result[1], value);
+  ASSERT_EQUAL(result[2], value);
+  ASSERT_EQUAL(result[3], value);
+  ASSERT_EQUAL(result[4], value);
+
+  cudaStreamDestroy(s);
+}
+DECLARE_UNITTEST(TestGenerateCudaStreams);
+
+#ifdef THRUST_TEST_DEVICE_SIDE
+template <typename ExecutionPolicy, typename Iterator, typename Size, typename Function>
+__global__ void generate_n_kernel(ExecutionPolicy exec, Iterator first, Size n, Function f)
+{
+  thrust::generate_n(exec, first, n, f);
+}
+
+template <typename T, typename ExecutionPolicy>
+void TestGenerateNDevice(ExecutionPolicy exec, const size_t n)
+{
+  thrust::host_vector<T> h_result(n);
+  thrust::device_vector<T> d_result(n);
+
+  T value = 13;
+  return_value<T> f(value);
+
+  thrust::generate_n(h_result.begin(), h_result.size(), f);
+
+  generate_n_kernel<<<1, 1>>>(exec, d_result.begin(), d_result.size(), f);
+  {
+    cudaError_t const err = cudaDeviceSynchronize();
+    ASSERT_EQUAL(cudaSuccess, err);
+  }
+
+  ASSERT_EQUAL(h_result, d_result);
+}
+
+template <typename T>
+void TestGenerateNDeviceSeq(const size_t n)
+{
+  TestGenerateNDevice<T>(thrust::seq, n);
+}
+DECLARE_VARIABLE_UNITTEST(TestGenerateNDeviceSeq);
+
+template <typename T>
+void TestGenerateNDeviceDevice(const size_t n)
+{
+  TestGenerateNDevice<T>(thrust::device, n);
+}
+DECLARE_VARIABLE_UNITTEST(TestGenerateNDeviceDevice);
+#endif
+
+void TestGenerateNCudaStreams()
+{
+  thrust::device_vector<int> result(5);
+
+  int value = 13;
+
+  return_value<int> f(value);
+
+  cudaStream_t s;
+  cudaStreamCreate(&s);
+
+  thrust::generate_n(thrust::cuda::par.on(s), result.begin(), result.size(), f);
+  cudaStreamSynchronize(s);
+
+  ASSERT_EQUAL(result[0], value);
+  ASSERT_EQUAL(result[1], value);
+  ASSERT_EQUAL(result[2], value);
+  ASSERT_EQUAL(result[3], value);
+  ASSERT_EQUAL(result[4], value);
+
+  cudaStreamDestroy(s);
+}
+DECLARE_UNITTEST(TestGenerateNCudaStreams);