Imported Upstream version 1.1.0upstream/1.1.0

1 files changed, 163 insertions, 0 deletions

diff --git a/tests/src/JIT/Performance/CodeQuality/BenchF/Bisect/Bisect.cs b/tests/src/JIT/Performance/CodeQuality/BenchF/Bisect/Bisect.cs
new file mode 100644
index 0000000000..1c27003567
--- /dev/null
+++ b/tests/src/JIT/Performance/CodeQuality/BenchF/Bisect/Bisect.cs
@@ -0,0 +1,163 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+//
+// The Bisect algorithm adapted from Conte and de Boor
+
+using Microsoft.Xunit.Performance;
+using System;
+using System.Runtime.CompilerServices;
+using Xunit;
+
+[assembly: OptimizeForBenchmarks]
+[assembly: MeasureInstructionsRetired]
+
+public static class Bisect
+{
+#if DEBUG
+    public const int Iterations = 1;
+#else
+    public const int Iterations = 400000;
+#endif
+
+    public static volatile object VolatileObject;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    private static void Escape(object obj)
+    {
+        VolatileObject = obj;
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    private static bool Bench()
+    {
+        int idbg, iflag;
+        double a, b, error, p1, xi;
+
+        iflag = 0;
+        error = 0.0;
+        xi = 0.0;
+        idbg = 0;
+        for (int i = 1; i <= Iterations; i++)
+        {
+            for (int j = 1; j <= 10; j++)
+            {
+                a = 1.0;
+                b = 2.0;
+                p1 = 0.000001;
+                Inner(ref a, ref b, ref p1, out iflag);
+                if (iflag > 1)
+                {
+                    goto L999;
+                }
+
+                xi = (a + b) / 2.0;
+                if (a > b)
+                {
+                    error = (a - b) / 2.0;
+                }
+                else
+                {
+                    error = (b - a) / 2.0;
+                }
+
+                if (idbg != 0)
+                {
+                    System.Console.WriteLine(" the root is {0:E} plus/minus {1:E}\n", xi, error);
+                }
+            }
+        }
+    L999:
+        {
+        }
+
+        // Escape iflag, error, xi so that they appear live
+        Escape(iflag);
+        Escape(error);
+        Escape(xi);
+
+        return true;
+    }
+
+    private static double FF(double x)
+    {
+        return ((-1.0 - (x * (1.0 - (x * x)))));
+    }
+
+    private static void Inner(ref double a, ref double b, ref double xtol, out int iflag)
+    {
+        double fa, error;
+        double xm, fm;
+
+        iflag = 0;
+        fa = FF(a);
+        /*      check for sign change  */
+        if (((fa) * FF(b)) < 0.0)
+        {
+            goto L5;
+        }
+
+        iflag = 2;
+        goto L99;
+
+    L5:
+        {
+            error = System.Math.Abs(b - a);
+        }
+    L6:
+        error = error / 2.0;
+        /*      check for sufficiently small interval  */
+        if (error < xtol)
+        {
+            goto L99;
+        }
+        xm = (a + b) / 2.0;
+        /*      check for unreasonable error requirement */
+        if (xm + error == xm)
+        {
+            goto L20;
+        }
+
+        fm = FF(xm);
+        /*      change to new interval  */
+        if (fa * fm < 0.0)
+        {
+            goto L9;
+        }
+        a = xm;
+        fa = fm;
+        goto L6;
+    L9:
+        b = xm;
+        goto L6;
+    L20:
+        iflag = 1;
+    L99:
+        {
+        }
+    }
+
+    [Benchmark]
+    public static void Test()
+    {
+        foreach (var iteration in Benchmark.Iterations)
+        {
+            using (iteration.StartMeasurement())
+            {
+                Bench();
+            }
+        }
+    }
+
+    private static bool TestBase()
+    {
+        bool result = Bench();
+        return result;
+    }
+
+    public static int Main()
+    {
+        bool result = TestBase();
+        return (result ? 100 : -1);
+    }
+}