Half conversion benchmarks (#2950)

Author: MineCake147E

src/benchmarks/micro/MicroBenchmarks.csproj

@@ -147,6 +147,7 @@
     <Compile Remove="libraries\System.Text.Json\Serializer\WritePreservedReferences.cs" />
     <Compile Remove="libraries\System.Net.Security\SslStreamTests.Context.cs" />
     <Compile Remove="libraries\System.Formats.Cbor\*.cs" />
+    <Compile Remove="libraries\System.Runtime\Perf.Half.cs" />
   </ItemGroup>
 
   <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' Or ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And '$(_TargetFrameworkVersionWithoutV)' &lt; '6.0')">
@@ -217,5 +218,4 @@
     <!-- Workaround https://github.com/dotnet/project-system/issues/935 -->
     <None Include="**/*.cs" />
   </ItemGroup>
-
 </Project>

src/benchmarks/micro/libraries/System.Runtime/Perf.Half.cs

@@ -0,0 +1,43 @@
+// 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.
+
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+using BenchmarkDotNet.Attributes;
+
+using MicroBenchmarks;
+
+namespace System.Tests
+{
+    [BenchmarkCategory(Categories.Libraries)]
+    public class Perf_Half
+    {
+        public static IEnumerable<Half> Values => new Half[]
+        {
+            BitConverter.UInt16BitsToHalf(0x03ff),  //Maximum subnormal number in Half
+            (Half)12345.0f /* same value used by other tests to compare the perf */,
+            BitConverter.UInt16BitsToHalf(0x7dff)   //NaN
+        };
+
+        public static IEnumerable<float> SingleValues => new float[]
+        {
+            6.097555E-05f,
+            12345.0f /* same value used by other tests to compare the perf */,
+            65520.0f,   //Minimum value that is infinity in Half
+            float.NaN
+        };
+
+        [Benchmark]
+        [ArgumentsSource(nameof(SingleValues))]
+        public Half SingleToHalf(float value) => (Half)value;
+
+        [Benchmark]
+        [ArgumentsSource(nameof(Values))]
+        public float HalfToSingle(Half value) => (float)value;
+    }
+}