Improve performance of Enum.CompareTo

[jkotas]

Enum.CompareTo was rewritten in C# recently. This set of fixes gets the performance on par with the previous C++ implementation

• Add optimization for obj1.GetType() == obj2.GetType() pattern the JIT
• Optimize FCall used by Enum.CompareTo

Fixes DrewScoggins/performance-2#525

[AndyAyersMS]

LGTM.

Did you try running diffs?

[jkotas]

Total bytes of diff: -2299 (-0.007% of base)
    diff is an improvement.
Top file improvements (bytes):
       -1747 : System.Private.CoreLib.dasm (-0.054% of base)
         -97 : System.Security.Permissions.dasm (-0.595% of base)
         -80 : System.Configuration.ConfigurationManager.dasm (-0.026% of base)
         -78 : Microsoft.CodeAnalysis.dasm (-0.010% of base)
         -74 : Microsoft.CSharp.dasm (-0.023% of base)
         -50 : System.Data.Common.dasm (-0.005% of base)
         -41 : xunit.assert.dasm (-0.083% of base)
         -30 : Microsoft.VisualBasic.Core.dasm (-0.007% of base)
         -27 : Microsoft.Diagnostics.NETCore.Client.dasm (-0.322% of base)
         -21 : System.ComponentModel.TypeConverter.dasm (-0.009% of base)
         -18 : Newtonsoft.Json.dasm (-0.003% of base)
         -18 : System.Private.Xml.dasm (-0.001% of base)
          -9 : xunit.core.dasm (-0.039% of base)
          -9 : xunit.execution.dotnet.dasm (-0.005% of base)
14 total files with Code Size differences (14 improved, 0 regressed), 249 unchanged.
Top method improvements (bytes):
       -1044 (-63.158% of base) : System.Private.CoreLib.dasm - GenericComparer`1:Equals(Object):bool:this (29 methods)
        -216 (-63.158% of base) : System.Private.CoreLib.dasm - ObjectEqualityComparer`1:Equals(Object):bool:this (6 methods)
        -108 (-63.158% of base) : System.Private.CoreLib.dasm - ObjectComparer`1:Equals(Object):bool:this (3 methods)
         -72 (-63.158% of base) : System.Private.CoreLib.dasm - NullableEqualityComparer`1:Equals(Object):bool:this (2 methods)
         -72 (-63.158% of base) : System.Private.CoreLib.dasm - NullableComparer`1:Equals(Object):bool:this (2 methods)
         -44 (-11.828% of base) : Microsoft.CSharp.dasm - ComEventsMethod:RemoveDelegate(Delegate,bool):this
         -44 (-11.733% of base) : System.Private.CoreLib.dasm - ComEventsMethod:RemoveDelegate(Delegate,bool):this
         -39 (-7.276% of base) : System.Configuration.ConfigurationManager.dasm - ConfigurationElement:SetLocked():this
         -39 (-65.000% of base) : System.Security.Permissions.dasm - PrincipalPermission:VerifyType(IPermission):bool:this
         -36 (-63.158% of base) : System.Private.CoreLib.dasm - EnumComparer`1:Equals(Object):bool:this
         -36 (-63.158% of base) : System.Private.CoreLib.dasm - ByteEqualityComparer:Equals(Object):bool:this
         -36 (-63.158% of base) : System.Private.CoreLib.dasm - EnumEqualityComparer`1:Equals(Object):bool:this
         -34 (-3.469% of base) : System.Private.CoreLib.dasm - Array:Copy(Array,int,Array,int,int,bool)
         -30 (-6.928% of base) : Microsoft.CSharp.dasm - ComEventsMethod:AddDelegate(Delegate,bool):this
         -30 (-38.462% of base) : Microsoft.VisualBasic.Core.dasm - FastList:DataIsEqual(Object,Object):bool:this
         -27 (-28.723% of base) : Microsoft.CodeAnalysis.dasm - XmlFileResolver:Equals(Object):bool:this
         -27 (-31.395% of base) : Microsoft.CodeAnalysis.dasm - SourceFileResolver:Equals(Object):bool:this
         -27 (-31.395% of base) : Microsoft.Diagnostics.NETCore.Client.dasm - EventPipeProvider:Equals(Object):bool:this
         -24 (-21.818% of base) : Microsoft.CodeAnalysis.dasm - DesktopStrongNameProvider:Equals(Object):bool:this
         -23 (-10.798% of base) : System.Data.Common.dasm - ObjectStorage:CompareValueTo(int,Object):int:this
Top method improvements (percentages):
         -39 (-65.000% of base) : System.Security.Permissions.dasm - PrincipalPermission:VerifyType(IPermission):bool:this
         -36 (-63.158% of base) : System.Private.CoreLib.dasm - EnumComparer`1:Equals(Object):bool:this
         -36 (-63.158% of base) : System.Private.CoreLib.dasm - ByteEqualityComparer:Equals(Object):bool:this
         -36 (-63.158% of base) : System.Private.CoreLib.dasm - EnumEqualityComparer`1:Equals(Object):bool:this
         -72 (-63.158% of base) : System.Private.CoreLib.dasm - NullableEqualityComparer`1:Equals(Object):bool:this (2 methods)
         -72 (-63.158% of base) : System.Private.CoreLib.dasm - NullableComparer`1:Equals(Object):bool:this (2 methods)
        -108 (-63.158% of base) : System.Private.CoreLib.dasm - ObjectComparer`1:Equals(Object):bool:this (3 methods)
        -216 (-63.158% of base) : System.Private.CoreLib.dasm - ObjectEqualityComparer`1:Equals(Object):bool:this (6 methods)
       -1044 (-63.158% of base) : System.Private.CoreLib.dasm - GenericComparer`1:Equals(Object):bool:this (29 methods)
         -30 (-38.462% of base) : Microsoft.VisualBasic.Core.dasm - FastList:DataIsEqual(Object,Object):bool:this
         -27 (-31.395% of base) : Microsoft.CodeAnalysis.dasm - SourceFileResolver:Equals(Object):bool:this
         -27 (-31.395% of base) : Microsoft.Diagnostics.NETCore.Client.dasm - EventPipeProvider:Equals(Object):bool:this
         -27 (-28.723% of base) : Microsoft.CodeAnalysis.dasm - XmlFileResolver:Equals(Object):bool:this
         -24 (-21.818% of base) : Microsoft.CodeAnalysis.dasm - DesktopStrongNameProvider:Equals(Object):bool:this
         -44 (-11.828% of base) : Microsoft.CSharp.dasm - ComEventsMethod:RemoveDelegate(Delegate,bool):this
         -44 (-11.733% of base) : System.Private.CoreLib.dasm - ComEventsMethod:RemoveDelegate(Delegate,bool):this
         -23 (-10.798% of base) : System.Data.Common.dasm - ObjectStorage:CompareValueTo(int,Object):int:this
         -39 (-7.276% of base) : System.Configuration.ConfigurationManager.dasm - ConfigurationElement:SetLocked():this
         -30 (-6.928% of base) : Microsoft.CSharp.dasm - ComEventsMethod:AddDelegate(Delegate,bool):this
         -23 (-5.569% of base) : System.Private.CoreLib.dasm - ComEventsMethod:AddDelegate(Delegate,bool):this
38 total methods with Code Size differences (38 improved, 0 regressed), 186728 unchanged.

[DrewScoggins]

Moved this issue to the runtime repo for posterity: #39740

[Saibamen]

Do you have benchmark times before and after this PR?

[jkotas]

Sorry, I forgot the paste the throughput numbers into the PR. It was within noise range (<5%) of the baseline. @DrewScoggins Are there official perf numbers with this fix available?

[DrewScoggins]

You can see the improvement after @jkotas checkin below.