Update Tests for uniform_int_distribution

Author: LRFLEW

libcxx/test/benchmarks/numeric/rand.uni.int.bench.cpp

@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM 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
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: c++03
+
+#include <benchmark/benchmark.h>
+#include <cstdint>
+#include <random>
+
+template <typename Eng, std::uint64_t Max>
+static void bm_rand_uni_int(benchmark::State& state) {
+  Eng eng;
+  std::uniform_int_distribution<std::uint64_t> dist(1ull, Max);
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(dist(eng));
+  }
+}
+
+// n = 1
+BENCHMARK(bm_rand_uni_int<std::minstd_rand0, 1ull << 20>);
+BENCHMARK(bm_rand_uni_int<std::ranlux24_base, 1ull << 20>);
+
+// n = 2, n0 = 2
+BENCHMARK(bm_rand_uni_int<std::minstd_rand0, 1ull << 40>);
+BENCHMARK(bm_rand_uni_int<std::ranlux24_base, 1ull << 40>);
+
+// n = 2, n0 = 1
+BENCHMARK(bm_rand_uni_int<std::minstd_rand0, 1ull << 41>);
+BENCHMARK(bm_rand_uni_int<std::ranlux24_base, 1ull << 41>);
+
+BENCHMARK_MAIN();