Migrate FormattingHelpers.CountDigits to using Lzcnt.X64

Commit migrated from https://github.com/dotnet/coreclr/commit/4742ebfbae24b37d0690d494756a60b53b022fb6

diff --git a/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/FormattingHelpers.CountDigits.cs b/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/FormattingHelpers.CountDigits.cs
index 8982803..35545c4 100644 (file)
--- a/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/FormattingHelpers.CountDigits.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/FormattingHelpers.CountDigits.cs
@@ -104,9 +104,9 @@ namespace System.Buffers.Text
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static int CountHexDigits(ulong value)
         {
-            if (Lzcnt.IsSupported && IntPtr.Size == 8)
+            if (Lzcnt.X64.IsSupported)
             {
-                int right = 64 - (int)Lzcnt.LeadingZeroCount(value | 1);
+                int right = 64 - (int)Lzcnt.X64.LeadingZeroCount(value | 1);
                 return (right + 3) >> 2;
             }