small arithmetic optimization

2-benchmarks/Just.PreciseMath.PerformanceComparison/Program.cs

@@ -0,0 +1,23 @@
+using BenchmarkDotNet.Reports;
+using BenchmarkDotNet.Running;
+
+BenchmarkSwitcher switcher = BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly);
+// Only these standalone discovery/help forms intentionally produce no reports.
+if (args is ["--list", "flat" or "tree"] or ["--help"] or ["-h"])
+{
+    switcher.Run(args);
+    return 0;
+}
+
+Summary[] summaries = [.. switcher.Run(args.Length == 0 ? ["--filter", "*"] : args)];
+// BenchmarkDotNet can return normally after validation, build, or execution
+// failures. Do not let CI mistake an empty or failed run for a passing smoke test.
+if (summaries.Length == 0 || summaries.Any(summary =>
+    summary.HasCriticalValidationErrors || summary.Reports.Length == 0 ||
+    summary.Reports.Any(report => !report.Success || report.ResultStatistics is null)))
+{
+    Console.Error.WriteLine("Benchmark run failed or produced no measurements.");
+    return 1;
+}
+
+return 0;