[JitDiff X64] [xtqqczze] Optimise char to hex conversion

[MihuBot]

Job completed in 17 minutes 2 seconds (remote runner delay: 52 seconds).
dotnet/runtime#116821

Diffs

Diffs

Found 98 files with textual diffs.

Summary of Code Size diffs:
(Lower is better)

Total bytes of base: 40945598
Total bytes of diff: 40944224
Total bytes of delta: -1374 (-0.00 % of base)
Total relative delta: -1.69
    diff is an improvement.
    relative diff is an improvement.


Total byte diff includes 0 bytes from reconciling methods
	Base had   16 unique methods,      256 unique bytes
	Diff had   16 unique methods,      256 unique bytes

Top file regressions (bytes):
          56 : System.Private.Xml.dasm (0.00 % of base)
           5 : System.Net.Primitives.dasm (0.00 % of base)
           1 : System.Text.Json.dasm (0.00 % of base)
           1 : System.Private.Uri.dasm (0.00 % of base)
           1 : System.Security.Cryptography.dasm (0.00 % of base)

Top file improvements (bytes):
       -1286 : System.Private.CoreLib.dasm (-0.02 % of base)
         -24 : System.Web.HttpUtility.dasm (-0.13 % of base)
         -21 : System.Private.DataContractSerialization.dasm (-0.00 % of base)
         -18 : System.Text.RegularExpressions.dasm (-0.00 % of base)
         -17 : System.Security.Cryptography.Pkcs.dasm (-0.00 % of base)
         -17 : System.Reflection.Metadata.dasm (-0.00 % of base)
         -17 : System.Security.Cryptography.Xml.dasm (-0.01 % of base)
         -17 : System.Diagnostics.DiagnosticSource.dasm (-0.01 % of base)
          -8 : System.Net.Http.dasm (-0.00 % of base)
          -7 : System.Net.HttpListener.dasm (-0.01 % of base)
          -6 : System.Net.NetworkInformation.dasm (-0.01 % of base)

16 total files with Code Size differences (11 improved, 5 regressed), 244 unchanged.

Top method regressions (bytes):
          57 (3.86 % of base) : System.Private.Xml.dasm - System.Xml.XmlConvert:DecodeName(System.String):System.String (FullOpts)
          16 (Infinity of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Reflection.Metadata.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Net.HttpListener.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Text.RegularExpressions.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Net.NetworkInformation.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Net.Primitives.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Web.HttpUtility.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Text.Json.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Net.Http.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Private.Xml.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Diagnostics.DiagnosticSource.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Private.Uri.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Security.Cryptography.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Private.CoreLib.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
           4 (10.26 % of base) : System.Private.Xml.dasm - System.Xml.XmlConvert:FromHex(char):int (FullOpts)
           1 (1.96 % of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Reflection.Metadata.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Net.HttpListener.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Text.RegularExpressions.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Net.NetworkInformation.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Net.Primitives.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Web.HttpUtility.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Text.Json.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Private.Xml.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Private.Uri.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Security.Cryptography.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (2.08 % of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (2.08 % of base) : System.Reflection.Metadata.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (2.08 % of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (2.08 % of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (2.08 % of base) : System.Net.Http.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (0.12 % of base) : System.Net.Primitives.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[int](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Private.Uri.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[int](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Net.Primitives.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[long](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Private.Uri.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[long](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Net.Primitives.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[short](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Private.Uri.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[short](ptr,int,byref,bool):long (FullOpts)
           1 (0.08 % of base) : System.Net.Primitives.dasm - System.Net.IPv6AddressHelper:Parse[byte](System.ReadOnlySpan`1[byte],System.Span`1[ushort],byref) (FullOpts)
           1 (0.08 % of base) : System.Private.Uri.dasm - System.Net.IPv6AddressHelper:Parse[byte](System.ReadOnlySpan`1[byte],System.Span`1[ushort],byref) (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.Number+HexParser`1[byte]:FromChar(uint):uint (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.Number+HexParser`1[int]:FromChar(uint):uint (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.Number+HexParser`1[long]:FromChar(uint):uint (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.Number+HexParser`1[short]:FromChar(uint):uint (FullOpts)

Top method improvements (bytes):
        -461 (-38.67 % of base) : System.Private.CoreLib.dasm - System.Guid:TryParseExactD[byte](System.ReadOnlySpan`1[byte],byref):bool (FullOpts)
        -460 (-40.96 % of base) : System.Private.CoreLib.dasm - System.Guid:TryParseExactN[byte](System.ReadOnlySpan`1[byte],byref):bool (FullOpts)
        -262 (-21.34 % of base) : System.Private.CoreLib.dasm - System.Guid:TryParseExactD[char](System.ReadOnlySpan`1[char],byref):bool (FullOpts)
         -20 (-8.30 % of base) : System.Private.CoreLib.dasm - System.Buffers.Text.Utf8Parser:TryParseUInt16X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
         -20 (-8.33 % of base) : System.Private.CoreLib.dasm - System.Buffers.Text.Utf8Parser:TryParseUInt32X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
         -20 (-31.25 % of base) : System.Private.CoreLib.dasm - System.Guid:DecodeByte[byte](byte,byte,byref):byte (FullOpts)
         -19 (-8.09 % of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
         -19 (-8.09 % of base) : System.Reflection.Metadata.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
         -19 (-8.09 % of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
         -19 (-8.09 % of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
         -19 (-8.09 % of base) : System.Private.CoreLib.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
         -16 (-100.00 % of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Reflection.Metadata.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Net.HttpListener.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Text.RegularExpressions.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Net.NetworkInformation.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Net.Primitives.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Web.HttpUtility.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Text.Json.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Net.Http.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Private.Xml.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Private.Uri.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Security.Cryptography.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Private.CoreLib.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-1.15 % of base) : System.Text.RegularExpressions.dasm - System.Text.RegularExpressions.RegexParser:ScanCharEscape():char:this (FullOpts) (2 methods)
         -12 (-3.92 % of base) : System.Private.CoreLib.dasm - System.Guid:TryParseHex[byte](System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts) (2 methods)
         -10 (-1.07 % of base) : System.Web.HttpUtility.dasm - System.Web.Util.HttpEncoder:UrlDecode(byte[],int,int,System.Text.Encoding):System.String (FullOpts)
          -9 (-0.87 % of base) : System.Web.HttpUtility.dasm - System.Web.Util.HttpEncoder:UrlDecode(System.ReadOnlySpan`1[char],System.Text.Encoding):System.String (FullOpts)
          -8 (-1.02 % of base) : System.Net.HttpListener.dasm - System.Net.HttpListenerRequest+Helpers:UrlDecodeStringFromStringInternal(System.String,System.Text.Encoding):System.String (FullOpts)
          -7 (-0.80 % of base) : System.Private.CoreLib.dasm - System.Net.WebUtility:UrlDecodeInternal(System.String,System.Text.Encoding):System.String (FullOpts)
          -6 (-0.24 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.Diagnostics.W3CPropagator:TryDecodeBaggageValue(System.ReadOnlySpan`1[char],byref):bool (FullOpts)
          -6 (-4.92 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.Diagnostics.W3CPropagator:TryDecodeEscapedByte(System.ReadOnlySpan`1[char],byref):bool (FullOpts)
          -6 (-0.64 % of base) : System.Net.Http.dasm - System.Net.Http.Headers.AltSvcHeaderParser:TryReadUnknownPercentEncodedAlpnProtocolName(System.ReadOnlySpan`1[char],byref):bool (FullOpts)
          -6 (-1.34 % of base) : System.Web.HttpUtility.dasm - System.Web.Util.HttpEncoder:UrlDecode(System.ReadOnlySpan`1[byte]):byte[] (FullOpts)
          -5 (-2.94 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.Diagnostics.ActivityTraceId:HexByteFromChars(char,char):byte (FullOpts)
          -5 (-1.16 % of base) : System.Private.CoreLib.dasm - System.Net.WebUtility:UrlDecodeInternal(byte[],int,int):byte[] (FullOpts)
          -4 (-1.79 % of base) : System.Private.CoreLib.dasm - System.Buffers.Text.Utf8Parser:TryParseByteX(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
          -4 (-0.59 % of base) : System.Net.NetworkInformation.dasm - System.Net.NetworkInformation.PhysicalAddress:TryParse(System.ReadOnlySpan`1[char],byref):bool (FullOpts)
          -4 (-1.47 % of base) : System.Private.Xml.dasm - System.Xml.BinHexDecoder:Decode(System.ReadOnlySpan`1[char],System.Span`1[byte],byref,byref,byref,byref) (FullOpts)
          -4 (-1.45 % of base) : System.Private.DataContractSerialization.dasm - System.Xml.XmlBufferReader:GetHexCharEntity(int,int):int:this (FullOpts)
          -3 (-5.17 % of base) : System.Net.Http.dasm - System.Net.Http.Headers.AltSvcHeaderParser:TryReadAlpnHexDigit(char,byref):bool (FullOpts)
          -3 (-4.23 % of base) : System.Net.NetworkInformation.dasm - System.Net.NetworkInformation.StringParsingHelpers:HexToByte(char):byte (FullOpts)
          -3 (-1.78 % of base) : System.Text.RegularExpressions.dasm - System.Text.RegularExpressions.RegexParser:ScanHex(int):char:this (FullOpts)
          -2 (-1.55 % of base) : System.Private.Uri.dasm - System.Uri:FromHex(char):int (FullOpts)
          -2 (-1.72 % of base) : System.Private.Uri.dasm - System.UriHelper:DecodeHexChars(int,int):char (FullOpts)
          -2 (-0.15 % of base) : System.Private.Xml.dasm - System.Xml.XmlTextReaderImpl:ParseNumericCharRefInline(int,bool,System.Text.StringBuilder,byref,byref):int:this (FullOpts)
          -1 (-0.39 % of base) : System.Private.CoreLib.dasm - System.Buffers.Text.Utf8Parser:TryParseUInt64X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
          -1 (-2.00 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.Diagnostics.W3CPropagator:TryDecodeHexDigit(char,byref):bool (FullOpts)

Top method regressions (percentages):
          16 (Infinity of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Reflection.Metadata.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Net.HttpListener.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Text.RegularExpressions.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Net.NetworkInformation.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Net.Primitives.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Web.HttpUtility.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Text.Json.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Net.Http.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Private.Xml.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Diagnostics.DiagnosticSource.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Private.Uri.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Security.Cryptography.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
          16 (Infinity of base) : System.Private.CoreLib.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[sbyte] (FullOpts) (0 base, 1 diff methods)
           4 (10.26 % of base) : System.Private.Xml.dasm - System.Xml.XmlConvert:FromHex(char):int (FullOpts)
          57 (3.86 % of base) : System.Private.Xml.dasm - System.Xml.XmlConvert:DecodeName(System.String):System.String (FullOpts)
           1 (2.08 % of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (2.08 % of base) : System.Reflection.Metadata.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (2.08 % of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (2.08 % of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (2.08 % of base) : System.Net.Http.dasm - System.HexConverter:FromUpperChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Reflection.Metadata.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Net.HttpListener.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Text.RegularExpressions.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Net.NetworkInformation.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Net.Primitives.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Web.HttpUtility.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Text.Json.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Private.Xml.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Private.Uri.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Security.Cryptography.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.HexConverter:FromChar(int):int (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.Number+HexParser`1[byte]:FromChar(uint):uint (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.Number+HexParser`1[int]:FromChar(uint):uint (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.Number+HexParser`1[long]:FromChar(uint):uint (FullOpts)
           1 (1.96 % of base) : System.Private.CoreLib.dasm - System.Number+HexParser`1[short]:FromChar(uint):uint (FullOpts)
           1 (0.12 % of base) : System.Net.Primitives.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[int](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Private.Uri.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[int](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Net.Primitives.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[long](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Private.Uri.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[long](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Net.Primitives.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[short](ptr,int,byref,bool):long (FullOpts)
           1 (0.12 % of base) : System.Private.Uri.dasm - System.Net.IPv4AddressHelper:ParseNonCanonical[short](ptr,int,byref,bool):long (FullOpts)
           1 (0.08 % of base) : System.Net.Primitives.dasm - System.Net.IPv6AddressHelper:Parse[byte](System.ReadOnlySpan`1[byte],System.Span`1[ushort],byref) (FullOpts)
           1 (0.08 % of base) : System.Private.Uri.dasm - System.Net.IPv6AddressHelper:Parse[byte](System.ReadOnlySpan`1[byte],System.Span`1[ushort],byref) (FullOpts)

Top method improvements (percentages):
         -16 (-100.00 % of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Reflection.Metadata.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Net.HttpListener.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Text.RegularExpressions.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Net.NetworkInformation.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Net.Primitives.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Web.HttpUtility.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Text.Json.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Net.Http.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Private.Xml.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Private.Uri.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Security.Cryptography.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
         -16 (-100.00 % of base) : System.Private.CoreLib.dasm - System.HexConverter:get_CharToHexLookup():System.ReadOnlySpan`1[byte] (FullOpts) (1 base, 0 diff methods)
        -460 (-40.96 % of base) : System.Private.CoreLib.dasm - System.Guid:TryParseExactN[byte](System.ReadOnlySpan`1[byte],byref):bool (FullOpts)
        -461 (-38.67 % of base) : System.Private.CoreLib.dasm - System.Guid:TryParseExactD[byte](System.ReadOnlySpan`1[byte],byref):bool (FullOpts)
         -20 (-31.25 % of base) : System.Private.CoreLib.dasm - System.Guid:DecodeByte[byte](byte,byte,byref):byte (FullOpts)
        -262 (-21.34 % of base) : System.Private.CoreLib.dasm - System.Guid:TryParseExactD[char](System.ReadOnlySpan`1[char],byref):bool (FullOpts)
         -20 (-8.33 % of base) : System.Private.CoreLib.dasm - System.Buffers.Text.Utf8Parser:TryParseUInt32X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
         -20 (-8.30 % of base) : System.Private.CoreLib.dasm - System.Buffers.Text.Utf8Parser:TryParseUInt16X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
         -19 (-8.09 % of base) : System.Security.Cryptography.Pkcs.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
         -19 (-8.09 % of base) : System.Reflection.Metadata.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
         -19 (-8.09 % of base) : System.Security.Cryptography.Xml.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
         -19 (-8.09 % of base) : System.Private.DataContractSerialization.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
         -19 (-8.09 % of base) : System.Private.CoreLib.dasm - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
          -3 (-5.17 % of base) : System.Net.Http.dasm - System.Net.Http.Headers.AltSvcHeaderParser:TryReadAlpnHexDigit(char,byref):bool (FullOpts)
          -6 (-4.92 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.Diagnostics.W3CPropagator:TryDecodeEscapedByte(System.ReadOnlySpan`1[char],byref):bool (FullOpts)
          -3 (-4.23 % of base) : System.Net.NetworkInformation.dasm - System.Net.NetworkInformation.StringParsingHelpers:HexToByte(char):byte (FullOpts)
         -12 (-3.92 % of base) : System.Private.CoreLib.dasm - System.Guid:TryParseHex[byte](System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts) (2 methods)
          -5 (-2.94 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.Diagnostics.ActivityTraceId:HexByteFromChars(char,char):byte (FullOpts)
          -1 (-2.00 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.Diagnostics.W3CPropagator:TryDecodeHexDigit(char,byref):bool (FullOpts)
          -4 (-1.79 % of base) : System.Private.CoreLib.dasm - System.Buffers.Text.Utf8Parser:TryParseByteX(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
          -3 (-1.78 % of base) : System.Text.RegularExpressions.dasm - System.Text.RegularExpressions.RegexParser:ScanHex(int):char:this (FullOpts)
          -2 (-1.72 % of base) : System.Private.Uri.dasm - System.UriHelper:DecodeHexChars(int,int):char (FullOpts)
          -2 (-1.55 % of base) : System.Private.Uri.dasm - System.Uri:FromHex(char):int (FullOpts)
          -4 (-1.47 % of base) : System.Private.Xml.dasm - System.Xml.BinHexDecoder:Decode(System.ReadOnlySpan`1[char],System.Span`1[byte],byref,byref,byref,byref) (FullOpts)
          -4 (-1.45 % of base) : System.Private.DataContractSerialization.dasm - System.Xml.XmlBufferReader:GetHexCharEntity(int,int):int:this (FullOpts)
          -6 (-1.34 % of base) : System.Web.HttpUtility.dasm - System.Web.Util.HttpEncoder:UrlDecode(System.ReadOnlySpan`1[byte]):byte[] (FullOpts)
          -5 (-1.16 % of base) : System.Private.CoreLib.dasm - System.Net.WebUtility:UrlDecodeInternal(byte[],int,int):byte[] (FullOpts)
         -16 (-1.15 % of base) : System.Text.RegularExpressions.dasm - System.Text.RegularExpressions.RegexParser:ScanCharEscape():char:this (FullOpts) (2 methods)
         -10 (-1.07 % of base) : System.Web.HttpUtility.dasm - System.Web.Util.HttpEncoder:UrlDecode(byte[],int,int,System.Text.Encoding):System.String (FullOpts)
          -8 (-1.02 % of base) : System.Net.HttpListener.dasm - System.Net.HttpListenerRequest+Helpers:UrlDecodeStringFromStringInternal(System.String,System.Text.Encoding):System.String (FullOpts)
          -9 (-0.87 % of base) : System.Web.HttpUtility.dasm - System.Web.Util.HttpEncoder:UrlDecode(System.ReadOnlySpan`1[char],System.Text.Encoding):System.String (FullOpts)
          -7 (-0.80 % of base) : System.Private.CoreLib.dasm - System.Net.WebUtility:UrlDecodeInternal(System.String,System.Text.Encoding):System.String (FullOpts)
          -6 (-0.64 % of base) : System.Net.Http.dasm - System.Net.Http.Headers.AltSvcHeaderParser:TryReadUnknownPercentEncodedAlpnProtocolName(System.ReadOnlySpan`1[char],byref):bool (FullOpts)
          -4 (-0.59 % of base) : System.Net.NetworkInformation.dasm - System.Net.NetworkInformation.PhysicalAddress:TryParse(System.ReadOnlySpan`1[char],byref):bool (FullOpts)
          -1 (-0.39 % of base) : System.Private.CoreLib.dasm - System.Buffers.Text.Utf8Parser:TryParseUInt64X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
          -6 (-0.24 % of base) : System.Diagnostics.DiagnosticSource.dasm - System.Diagnostics.W3CPropagator:TryDecodeBaggageValue(System.ReadOnlySpan`1[char],byref):bool (FullOpts)
          -2 (-0.15 % of base) : System.Private.Xml.dasm - System.Xml.XmlTextReaderImpl:ParseNumericCharRefInline(int,bool,System.Text.StringBuilder,byref,byref):int:this (FullOpts)

101 total methods with Code Size differences (51 improved, 50 regressed), 247853 unchanged.

--------------------------------------------------------------------------------

Artifacts:

• build-clr-checked-main.zip (88 MB)
• build-artifacts-main.zip (678 MB)
• build-clr-checked-pr.zip (88 MB)
• build-artifacts-pr.zip (678 MB)
• jit-diffs-main.zip (136 MB)
• jit-diffs-pr.zip (136 MB)
• diff-frameworks.txt (32 KB)
• ShortDiffsRegressions.md (57 KB)
• LongDiffsRegressions.md (118 KB)
• ShortDiffsImprovements.md (56 KB)
• LongDiffsImprovements.md (611 KB)

[MihuBot]

Top method regressions

4 (10.26 % of base) - System.Xml.XmlConvert:FromHex(char):int

 ; Assembly listing for method System.Xml.XmlConvert:FromHex(char):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 3 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  3,  3   )  ushort  ->  rdi         single-def
 ;# V01 OutArgs      [V01    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;  V02 tmp1         [V02,T02] (  3,  2   )     int  ->  rax         "Inline return value spill temp"
-;* V03 tmp2         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp3         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V05 tmp4         [V05    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;  V02 tmp1         [V02,T02] (  3,  2   )     int  ->  rcx         "Inline return value spill temp"
+;* V03 tmp2         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp3         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V05 tmp4         [V05    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V06 tmp5         [V06    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V07 tmp6         [V07    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V08 tmp7         [V08    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V09 tmp8         [V09    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;* V10 tmp9         [V10    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V05._reference (fldOffset=0x0)" P-INDEP
 ;* V11 tmp10        [V11    ] (  0,  0   )     int  ->  zero-ref    "field V05._length (fldOffset=0x8)" P-INDEP
 ;  V12 cse0         [V12,T01] (  3,  2.50)     int  ->  rax         "CSE #01: aggressive"
 ;
 ; Lcl frame size = 0
 
 G_M129_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M129_IG02:
        movzx    rax, di
        cmp      eax, 256
        jl       SHORT G_M129_IG04
 						;; size=10 bbWeight=1 PerfScore 1.50
 G_M129_IG03:
-       mov      eax, 255
+       mov      ecx, -1
        jmp      SHORT G_M129_IG05
 						;; size=7 bbWeight=0.50 PerfScore 1.12
 G_M129_IG04:
-       mov      eax, eax
-       mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=16 bbWeight=0.50 PerfScore 1.25
+       mov      ecx, eax
+       mov      rax, 0xD1FFAB1E      ; static handle
+       movsx    rcx, byte  ptr [rax+rcx]
+						;; size=17 bbWeight=0.50 PerfScore 2.25
 G_M129_IG05:
+       movzx    rax, cl
+						;; size=3 bbWeight=1 PerfScore 0.25
+G_M129_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=1 PerfScore 1.50
 
-; Total bytes of code 39, prolog size 4, PerfScore 6.62, instruction count 12, allocated bytes for code 39 (MethodHash=94dfff7e) for method System.Xml.XmlConvert:FromHex(char):int (FullOpts)
+; Total bytes of code 43, prolog size 4, PerfScore 7.88, instruction count 13, allocated bytes for code 43 (MethodHash=94dfff7e) for method System.Xml.XmlConvert:FromHex(char):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    single-def "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    single-def "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    single-def "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    single-def "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

1 (1.96 % of base) - System.HexConverter:FromChar(int):int

 ; Assembly listing for method System.HexConverter:FromChar(int):int (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; partially interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 2 single block inlinees; 2 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T00] (  5,  4   )     int  ->  rdi         single-def
-;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;* V01 loc0         [V01    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;# V02 OutArgs      [V02    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V03 tmp1         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V04 tmp2         [V04    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;* V05 tmp3         [V05    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;* V06 tmp4         [V06    ] (  0,  0   )     int  ->  zero-ref    "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V07 tmp5         [V07    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
 ;* V08 tmp6         [V08    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
 ;* V09 tmp7         [V09    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V04._reference (fldOffset=0x0)" P-INDEP
 ;* V10 tmp8         [V10    ] (  0,  0   )     int  ->  zero-ref    "field V04._length (fldOffset=0x8)" P-INDEP
 ;
 ; Lcl frame size = 0
 
 G_M45387_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M45387_IG02:
        cmp      edi, 256
        jl       SHORT G_M45387_IG05
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M45387_IG03:
-       mov      eax, 255
+       mov      eax, -1
 						;; size=5 bbWeight=0.50 PerfScore 0.12
 G_M45387_IG04:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG05:
        cmp      edi, 256
        jae      SHORT G_M45387_IG07
        mov      eax, edi
        mov      rcx, 0xD1FFAB1E      ; static handle
-       movzx    rax, byte  ptr [rcx+rax]
-						;; size=24 bbWeight=0.50 PerfScore 1.88
+       movsx    rax, byte  ptr [rcx+rax]
+						;; size=25 bbWeight=0.50 PerfScore 2.88
 G_M45387_IG06:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M45387_IG07:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 51, prolog size 4, PerfScore 6.00, instruction count 16, allocated bytes for code 51 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
+; Total bytes of code 52, prolog size 4, PerfScore 7.00, instruction count 16, allocated bytes for code 52 (MethodHash=f74e4eb4) for method System.HexConverter:FromChar(int):int (FullOpts)
 ; ============================================================

Note: some changes were skipped as they were too large to fit into a comment.

Larger list of diffs: https://gist.github.com/MihuBot/3ef99e4d94ae510efff76a70677e8bdb

[MihuBot]

Top method improvements

-20 (-8.30 % of base) - System.Buffers.Text.Utf8Parser:TryParseUInt16X(System.ReadOnlySpan`1[byte],byref,byref):bool

 ; Assembly listing for method System.Buffers.Text.Utf8Parser:TryParseUInt16X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; fully interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 1 single block inlinees; 1 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;* V00 arg0         [V00    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.ReadOnlySpan`1[byte]>
 ;  V01 arg1         [V01,T10] (  4,  3   )   byref  ->  rdx         single-def
 ;  V02 arg2         [V02,T09] (  7,  4.50)   byref  ->  rcx         single-def
 ;  V03 loc0         [V03,T02] (  8, 24.76)   ubyte  ->  registers  
-;  V04 loc1         [V04,T00] ( 12, 37.14)   ubyte  ->  registers  
-;* V05 loc2         [V05    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;  V04 loc1         [V04,T00] ( 12, 37.14)     int  ->  registers  
+;* V05 loc2         [V05    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;  V06 loc3         [V06,T01] (  9, 28.72)     int  ->   r9        
 ;  V07 loc4         [V07,T11] (  2,  1   )     int  ->  rax        
 ;  V08 loc5         [V08,T12] (  2,  1   )     int  ->  rdi        
 ;  V09 loc6         [V09,T13] (  2,  1   )     int  ->  rsi        
 ;# V10 OutArgs      [V10    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V11 tmp1         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V11 tmp1         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V12 tmp2         [V12,T06] (  5, 13.38)   byref  ->  rdi         single-def "field V00._reference (fldOffset=0x0)" P-INDEP
 ;  V13 tmp3         [V13,T07] (  7, 11.42)     int  ->  rsi         single-def "field V00._length (fldOffset=0x8)" P-INDEP
 ;  V14 tmp4         [V14,T08] (  4, 12.38)   byref  ->   r8         single-def "field V05._reference (fldOffset=0x0)" P-INDEP
 ;* V15 tmp5         [V15,T15] (  0,  0   )     int  ->  zero-ref    "field V05._length (fldOffset=0x8)" P-INDEP
 ;  V16 tmp6         [V16,T14] (  2,  1   )   byref  ->   r8         single-def "field V11._reference (fldOffset=0x0)" P-INDEP
 ;* V17 tmp7         [V17,T16] (  0,  0   )     int  ->  zero-ref    "field V11._length (fldOffset=0x8)" P-INDEP
 ;  V18 rat0         [V18,T03] (  6, 16.84)    long  ->  rax         "Widened IV V08"
 ;  V19 rat1         [V19,T04] (  6, 16.84)    long  ->  rax         "Widened IV V09"
 ;  V20 rat2         [V20,T05] (  6, 16.84)    long  ->  rax         "Widened IV V07"
 ;
 ; Lcl frame size = 0
 
 G_M46759_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M46759_IG02:
        test     esi, esi
        jle      G_M46759_IG08
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M46759_IG03:
        mov      r8, 0xD1FFAB1E      ; static handle
        movzx    r9, byte  ptr [rdi]
        mov      rax, 0xD1FFAB1E      ; static handle
-       movzx    r9, byte  ptr [rax+r9]
-       cmp      r9d, 255
-       je       SHORT G_M46759_IG08
-		  ;; NOP compensation instructions of 4 bytes.
+       movsx    r9, byte  ptr [rax+r9]
+       test     r9d, r9d
+       jl       SHORT G_M46759_IG08
        cmp      esi, 4
        jle      SHORT G_M46759_IG12
 		  ;; NOP compensation instructions of 4 bytes.
        mov      eax, 1
-       align    [0 bytes for IG04]
-						;; size=56 bbWeight=0.50 PerfScore 3.62
+       align    [4 bytes for IG04]
+						;; size=52 bbWeight=0.50 PerfScore 4.75
 G_M46759_IG04:
        movzx    r10, byte  ptr [rdi+rax]
-       movzx    r10, byte  ptr [r8+r10]
-       cmp      r10d, 255
-       je       SHORT G_M46759_IG11
+       movsx    r10, byte  ptr [r8+r10]
+       test     r10d, r10d
+       jl       SHORT G_M46759_IG11
        shl      r9d, 4
        add      r9d, r10d
        inc      eax
        cmp      eax, 4
        jl       SHORT G_M46759_IG04
-						;; size=33 bbWeight=3.96 PerfScore 29.70
+						;; size=29 bbWeight=3.96 PerfScore 37.62
 G_M46759_IG05:
        mov      eax, 4
        jmp      SHORT G_M46759_IG07
        align    [0 bytes for IG06]
 						;; size=7 bbWeight=0.50 PerfScore 1.12
 G_M46759_IG06:
        shl      r9d, 4
        add      r9d, r10d
        inc      eax
        cmp      eax, esi
        jge      SHORT G_M46759_IG14
 						;; size=13 bbWeight=3.96 PerfScore 8.91
 G_M46759_IG07:
        movzx    r10, byte  ptr [rdi+rax]
-       movzx    r10, byte  ptr [r8+r10]
-       cmp      r10d, 255
-       je       SHORT G_M46759_IG10
+       movsx    r10, byte  ptr [r8+r10]
+       test     r10d, r10d
+       jl       SHORT G_M46759_IG10
        cmp      r9d, 0xFFF
        jbe      SHORT G_M46759_IG06
-						;; size=28 bbWeight=3.96 PerfScore 25.74
+						;; size=24 bbWeight=3.96 PerfScore 33.66
 G_M46759_IG08:
        xor      eax, eax
        mov      dword ptr [rcx], eax
        mov      word  ptr [rdx], 0
 						;; size=9 bbWeight=0.50 PerfScore 1.12
 G_M46759_IG09:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M46759_IG10:
        mov      esi, eax
        mov      dword ptr [rcx], esi
        jmp      SHORT G_M46759_IG16
-       align    [10 bytes for IG13]
-						;; size=16 bbWeight=0.50 PerfScore 1.62
+       align    [6 bytes for IG13]
+						;; size=12 bbWeight=0.50 PerfScore 1.62
 G_M46759_IG11:
        mov      edi, eax
        mov      dword ptr [rcx], edi
        jmp      SHORT G_M46759_IG16
 						;; size=6 bbWeight=0.50 PerfScore 1.62
 G_M46759_IG12:
        mov      eax, 1
        cmp      esi, 1
        jle      SHORT G_M46759_IG14
 						;; size=10 bbWeight=0.50 PerfScore 0.75
 G_M46759_IG13:
        movzx    r10, byte  ptr [rdi+rax]
-       movzx    r10, byte  ptr [r8+r10]
-       cmp      r10d, 255
-       je       SHORT G_M46759_IG15
+       movsx    r10, byte  ptr [r8+r10]
+       test     r10d, r10d
+       jl       SHORT G_M46759_IG15
        shl      r9d, 4
        add      r9d, r10d
        inc      eax
        cmp      eax, esi
        jl       SHORT G_M46759_IG13
-						;; size=32 bbWeight=3.96 PerfScore 29.70
+						;; size=28 bbWeight=3.96 PerfScore 37.62
 G_M46759_IG14:
        mov      dword ptr [rcx], esi
        jmp      SHORT G_M46759_IG16
 						;; size=4 bbWeight=0.50 PerfScore 1.50
 G_M46759_IG15:
        mov      dword ptr [rcx], eax
 						;; size=2 bbWeight=0.50 PerfScore 0.50
 G_M46759_IG16:
        mov      word  ptr [rdx], r9w
        mov      eax, 1
 						;; size=9 bbWeight=0.50 PerfScore 0.62
 G_M46759_IG17:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 
-; Total bytes of code 241, prolog size 4, PerfScore 110.55, instruction count 68, allocated bytes for code 241 (MethodHash=276a4958) for method System.Buffers.Text.Utf8Parser:TryParseUInt16X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
+; Total bytes of code 221, prolog size 4, PerfScore 135.43, instruction count 68, allocated bytes for code 221 (MethodHash=276a4958) for method System.Buffers.Text.Utf8Parser:TryParseUInt16X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
 ; ============================================================

-20 (-8.33 % of base) - System.Buffers.Text.Utf8Parser:TryParseUInt32X(System.ReadOnlySpan`1[byte],byref,byref):bool

 ; Assembly listing for method System.Buffers.Text.Utf8Parser:TryParseUInt32X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; fully interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 1 single block inlinees; 1 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;* V00 arg0         [V00    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.ReadOnlySpan`1[byte]>
 ;  V01 arg1         [V01,T10] (  4,  3   )   byref  ->  rdx         single-def
 ;  V02 arg2         [V02,T09] (  7,  4.50)   byref  ->  rcx         single-def
 ;  V03 loc0         [V03,T02] (  8, 24.76)   ubyte  ->  registers  
-;  V04 loc1         [V04,T00] ( 12, 37.14)   ubyte  ->  registers  
-;* V05 loc2         [V05    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
+;  V04 loc1         [V04,T00] ( 12, 37.14)     int  ->  registers  
+;* V05 loc2         [V05    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
 ;  V06 loc3         [V06,T01] (  9, 28.72)     int  ->   r9        
 ;  V07 loc4         [V07,T11] (  2,  1   )     int  ->  rax        
 ;  V08 loc5         [V08,T12] (  2,  1   )     int  ->  rdi        
 ;  V09 loc6         [V09,T13] (  2,  1   )     int  ->  rsi        
 ;# V10 OutArgs      [V10    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;* V11 tmp1         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V11 tmp1         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V12 tmp2         [V12,T06] (  5, 13.38)   byref  ->  rdi         single-def "field V00._reference (fldOffset=0x0)" P-INDEP
 ;  V13 tmp3         [V13,T07] (  7, 11.42)     int  ->  rsi         single-def "field V00._length (fldOffset=0x8)" P-INDEP
 ;  V14 tmp4         [V14,T08] (  4, 12.38)   byref  ->   r8         single-def "field V05._reference (fldOffset=0x0)" P-INDEP
 ;* V15 tmp5         [V15,T15] (  0,  0   )     int  ->  zero-ref    "field V05._length (fldOffset=0x8)" P-INDEP
 ;  V16 tmp6         [V16,T14] (  2,  1   )   byref  ->   r8         single-def "field V11._reference (fldOffset=0x0)" P-INDEP
 ;* V17 tmp7         [V17,T16] (  0,  0   )     int  ->  zero-ref    "field V11._length (fldOffset=0x8)" P-INDEP
 ;  V18 rat0         [V18,T03] (  6, 16.84)    long  ->  rax         "Widened IV V08"
 ;  V19 rat1         [V19,T04] (  6, 16.84)    long  ->  rax         "Widened IV V09"
 ;  V20 rat2         [V20,T05] (  6, 16.84)    long  ->  rax         "Widened IV V07"
 ;
 ; Lcl frame size = 0
 
 G_M8481_IG01:
        push     rbp
        mov      rbp, rsp
 						;; size=4 bbWeight=1 PerfScore 1.25
 G_M8481_IG02:
        test     esi, esi
        jle      G_M8481_IG08
 						;; size=8 bbWeight=1 PerfScore 1.25
 G_M8481_IG03:
        mov      r8, 0xD1FFAB1E      ; static handle
        movzx    r9, byte  ptr [rdi]
        mov      rax, 0xD1FFAB1E      ; static handle
-       movzx    r9, byte  ptr [rax+r9]
-       cmp      r9d, 255
-       je       SHORT G_M8481_IG08
-		  ;; NOP compensation instructions of 4 bytes.
+       movsx    r9, byte  ptr [rax+r9]
+       test     r9d, r9d
+       jl       SHORT G_M8481_IG08
        cmp      esi, 8
        jle      SHORT G_M8481_IG13
 		  ;; NOP compensation instructions of 4 bytes.
        mov      eax, 1
-       align    [0 bytes for IG04]
-						;; size=56 bbWeight=0.50 PerfScore 3.62
+       align    [4 bytes for IG04]
+						;; size=52 bbWeight=0.50 PerfScore 4.75
 G_M8481_IG04:
        movzx    r10, byte  ptr [rdi+rax]
-       movzx    r10, byte  ptr [r8+r10]
-       cmp      r10d, 255
-       je       SHORT G_M8481_IG12
+       movsx    r10, byte  ptr [r8+r10]
+       test     r10d, r10d
+       jl       SHORT G_M8481_IG12
        shl      r9d, 4
        add      r9d, r10d
        inc      eax
        cmp      eax, 8
        jl       SHORT G_M8481_IG04
-						;; size=33 bbWeight=3.96 PerfScore 29.70
+						;; size=29 bbWeight=3.96 PerfScore 37.62
 G_M8481_IG05:
        mov      eax, 8
        jmp      SHORT G_M8481_IG07
        align    [0 bytes for IG06]
 						;; size=7 bbWeight=0.50 PerfScore 1.12
 G_M8481_IG06:
        shl      r9d, 4
        add      r9d, r10d
        inc      eax
        cmp      eax, esi
        jge      SHORT G_M8481_IG15
 						;; size=13 bbWeight=3.96 PerfScore 8.91
 G_M8481_IG07:
        movzx    r10, byte  ptr [rdi+rax]
-       movzx    r10, byte  ptr [r8+r10]
-       cmp      r10d, 255
-       je       SHORT G_M8481_IG11
+       movsx    r10, byte  ptr [r8+r10]
+       test     r10d, r10d
+       jl       SHORT G_M8481_IG11
        cmp      r9d, 0xD1FFAB1E
        jbe      SHORT G_M8481_IG06
-						;; size=28 bbWeight=3.96 PerfScore 25.74
+						;; size=24 bbWeight=3.96 PerfScore 33.66
 G_M8481_IG08:
        xor      eax, eax
        mov      dword ptr [rcx], eax
 						;; size=4 bbWeight=0.50 PerfScore 0.62
 G_M8481_IG09:
        mov      dword ptr [rdx], eax
 						;; size=2 bbWeight=0.50 PerfScore 0.50
 G_M8481_IG10:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 G_M8481_IG11:
        mov      esi, eax
        mov      dword ptr [rcx], esi
        jmp      SHORT G_M8481_IG17
-       align    [13 bytes for IG14]
-						;; size=19 bbWeight=0.50 PerfScore 1.62
+       align    [9 bytes for IG14]
+						;; size=15 bbWeight=0.50 PerfScore 1.62
 G_M8481_IG12:
        mov      edi, eax
        mov      dword ptr [rcx], edi
        jmp      SHORT G_M8481_IG17
 						;; size=6 bbWeight=0.50 PerfScore 1.62
 G_M8481_IG13:
        mov      eax, 1
        cmp      esi, 1
        jle      SHORT G_M8481_IG15
 						;; size=10 bbWeight=0.50 PerfScore 0.75
 G_M8481_IG14:
        movzx    r10, byte  ptr [rdi+rax]
-       movzx    r10, byte  ptr [r8+r10]
-       cmp      r10d, 255
-       je       SHORT G_M8481_IG16
+       movsx    r10, byte  ptr [r8+r10]
+       test     r10d, r10d
+       jl       SHORT G_M8481_IG16
        shl      r9d, 4
        add      r9d, r10d
        inc      eax
        cmp      eax, esi
        jl       SHORT G_M8481_IG14
-						;; size=32 bbWeight=3.96 PerfScore 29.70
+						;; size=28 bbWeight=3.96 PerfScore 37.62
 G_M8481_IG15:
        mov      dword ptr [rcx], esi
        jmp      SHORT G_M8481_IG17
 						;; size=4 bbWeight=0.50 PerfScore 1.50
 G_M8481_IG16:
        mov      dword ptr [rcx], eax
 						;; size=2 bbWeight=0.50 PerfScore 0.50
 G_M8481_IG17:
        mov      dword ptr [rdx], r9d
        mov      eax, 1
 						;; size=8 bbWeight=0.50 PerfScore 0.62
 G_M8481_IG18:
        pop      rbp
        ret      
 						;; size=2 bbWeight=0.50 PerfScore 0.75
 
-; Total bytes of code 240, prolog size 4, PerfScore 110.55, instruction count 68, allocated bytes for code 240 (MethodHash=a6c5dede) for method System.Buffers.Text.Utf8Parser:TryParseUInt32X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
+; Total bytes of code 220, prolog size 4, PerfScore 135.43, instruction count 68, allocated bytes for code 220 (MethodHash=a6c5dede) for method System.Buffers.Text.Utf8Parser:TryParseUInt32X(System.ReadOnlySpan`1[byte],byref,byref):bool (FullOpts)
 ; ============================================================

-20 (-31.25 % of base) - System.Guid:DecodeByte[byte](byte,byte,byref):byte

 ; Assembly listing for method System.Guid:DecodeByte[byte](byte,byte,byref):byte (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
-; rsp based frame
+; rbp based frame
 ; partially interruptible
 ; No PGO data
-; 0 inlinees with PGO data; 3 single block inlinees; 3 inlinees without PGO data
+; 0 inlinees with PGO data; 3 single block inlinees; 1 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;  V00 arg0         [V00,T01] (  3,  3   )   ubyte  ->  rdi         single-def
 ;  V01 arg1         [V01,T02] (  3,  3   )   ubyte  ->  rsi         single-def
 ;  V02 arg2         [V02,T00] (  4,  4   )   byref  ->  rdx         single-def
-;* V03 loc0         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[byte]>
-;* V04 loc1         [V04    ] (  0,  0   )     int  ->  zero-ref   
-;  V05 loc2         [V05,T10] (  2,  2   )     int  ->  rcx        
+;* V03 loc0         [V03    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op <System.ReadOnlySpan`1[sbyte]>
+;  V04 loc1         [V04,T05] (  2,  2   )     int  ->  rax        
+;  V05 loc2         [V05,T06] (  2,  2   )     int  ->  rcx        
 ;* V06 loc3         [V06    ] (  0,  0   )     int  ->  zero-ref   
-;# V07 OutArgs      [V07    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
-;  V08 tmp1         [V08,T03] (  2,  4   )     int  ->  rcx         "Span.get_Item index"
-;  V09 tmp2         [V09,T04] (  2,  4   )     int  ->  rcx         "impAppendStmt"
-;  V10 tmp3         [V10,T05] (  2,  4   )     int  ->   r8         "Span.get_Item index"
-;* V11 tmp4         [V11    ] (  0,  0   )     int  ->  zero-ref    "impAppendStmt"
-;  V12 tmp5         [V12,T07] (  3,  3   )     int  ->  rcx        
-;* V13 tmp6         [V13    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V14 tmp7         [V14    ] (  0,  0   )   ubyte  ->  zero-ref    ld-addr-op "Inline stloc first use temp"
-;* V15 tmp8         [V15    ] (  0,  0   )   ubyte  ->  zero-ref    ld-addr-op "Inline stloc first use temp"
-;* V16 tmp9         [V16    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
-;* V17 tmp10        [V17    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
-;* V18 tmp11        [V18    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V13._reference (fldOffset=0x0)" P-INDEP
-;* V19 tmp12        [V19    ] (  0,  0   )     int  ->  zero-ref    "field V13._length (fldOffset=0x8)" P-INDEP
-;  V20 cse0         [V20,T06] (  3,  3   )   byref  ->  rdi         "CSE #01: moderate"
-;  V21 cse1         [V21,T08] (  3,  3   )     int  ->  rax         "CSE #02: moderate"
-;  V22 cse2         [V22,T09] (  3,  3   )     int  ->  rsi         "CSE #03: moderate"
+;  V07 loc4         [V07,T04] (  3,  3   )     int  ->  rax        
+;# V08 OutArgs      [V08    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
+;* V09 tmp1         [V09    ] (  0,  0   )     int  ->  zero-ref   
+;* V10 tmp2         [V10    ] (  0,  0   )     int  ->  zero-ref   
+;* V11 tmp3         [V11    ] (  0,  0   )     int  ->  zero-ref    "impAppendStmt"
+;* V12 tmp4         [V12    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V13 tmp5         [V13    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V03._reference (fldOffset=0x0)" P-INDEP
+;* V14 tmp6         [V14    ] (  0,  0   )     int  ->  zero-ref    "field V03._length (fldOffset=0x8)" P-INDEP
+;* V15 tmp7         [V15    ] (  0,  0   )   byref  ->  zero-ref    single-def "field V12._reference (fldOffset=0x0)" P-INDEP
+;* V16 tmp8         [V16    ] (  0,  0   )     int  ->  zero-ref    "field V12._length (fldOffset=0x8)" P-INDEP
+;  V17 cse0         [V17,T03] (  3,  3   )   byref  ->  rdi         "CSE #01: aggressive"
 ;
 ; Lcl frame size = 0
 
 G_M7685_IG01:
-						;; size=0 bbWeight=1 PerfScore 0.00
+       push     rbp
+       mov      rbp, rsp
+						;; size=4 bbWeight=1 PerfScore 1.25
 G_M7685_IG02:
        movzx    rax, dil
-       mov      ecx, eax
+       movzx    rcx, sil
        mov      rdi, 0xD1FFAB1E      ; static handle
-       movzx    rcx, byte  ptr [rdi+rcx]
-       movsx    rcx, cl
-       movzx    rsi, sil
-       mov      r8d, esi
-       movzx    rdi, byte  ptr [rdi+r8]
-       movsx    rdi, dil
-       shl      ecx, 4
-       or       ecx, edi
-       or       eax, esi
-       mov      edi, -1
-       shr      eax, 8
-       cmovne   ecx, edi
-       or       dword ptr [rdx], ecx
-       movzx    rax, cl
-						;; size=63 bbWeight=1 PerfScore 11.00
+       movsx    rax, byte  ptr [rdi+rax]
+       shl      eax, 4
+       movsx    rcx, byte  ptr [rdi+rcx]
+       or       eax, ecx
+       or       dword ptr [rdx], eax
+       movzx    rax, al
+						;; size=38 bbWeight=1 PerfScore 12.75
 G_M7685_IG03:
+       pop      rbp
        ret      
-						;; size=1 bbWeight=1 PerfScore 1.00
+						;; size=2 bbWeight=1 PerfScore 1.50
 
-; Total bytes of code 64, prolog size 0, PerfScore 12.00, instruction count 18, allocated bytes for code 64 (MethodHash=3108e1fa) for method System.Guid:DecodeByte[byte](byte,byte,byref):byte (FullOpts)
+; Total bytes of code 44, prolog size 4, PerfScore 15.50, instruction count 13, allocated bytes for code 44 (MethodHash=3108e1fa) for method System.Guid:DecodeByte[byte](byte,byte,byref):byte (FullOpts)
 ; ============================================================

-19 (-8.09 % of base) - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool

 ; Assembly listing for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; fully interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 4 single block inlinees; 6 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;* V00 arg0         [V00    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.ReadOnlySpan`1[char]>
 ;* V01 arg1         [V01    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.Span`1[byte]>
 ;  V02 arg2         [V02,T14] (  3,  3   )   byref  ->   r8         single-def
 ;  V03 loc0         [V03,T13] (  5,  5   )     int  ->  rax        
 ;  V04 loc1         [V04,T02] (  5, 26   )     int  ->  registers  
 ;  V05 loc2         [V05,T05] (  6, 19   )     int  ->   r9        
 ;  V06 loc3         [V06,T06] (  5, 18   )     int  ->  r10        
 ;# V07 OutArgs      [V07    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
 ;  V08 tmp1         [V08,T00] (  3, 48   )     int  ->  rax         "impSpillLclRefs"
 ;  V09 tmp2         [V09,T11] (  3,  8   )     int  ->  r10         "Inline return value spill temp"
 ;  V10 tmp3         [V10,T03] (  3, 20   )     int  ->   r9         "Inlining Arg"
-;* V11 tmp4         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[byte]>
-;* V12 tmp5         [V12    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V13 tmp6         [V13    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V11 tmp4         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[sbyte]>
+;* V12 tmp5         [V12    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V13 tmp6         [V13    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V14 tmp7         [V14,T12] (  3,  8   )     int  ->  rbx         "Inline return value spill temp"
 ;  V15 tmp8         [V15,T04] (  3, 20   )     int  ->  r10         "Inlining Arg"
-;* V16 tmp9         [V16    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[byte]>
-;* V17 tmp10        [V17    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V18 tmp11        [V18    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V16 tmp9         [V16    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[sbyte]>
+;* V17 tmp10        [V17    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V18 tmp11        [V18    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V19 tmp12        [V19,T08] (  3,  9   )   byref  ->  rdi         single-def "field V00._reference (fldOffset=0x0)" P-INDEP
 ;  V20 tmp13        [V20,T09] (  3,  9   )     int  ->  rsi         single-def "field V00._length (fldOffset=0x8)" P-INDEP
 ;  V21 tmp14        [V21,T10] (  2,  9   )   byref  ->  rdx         single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;  V22 tmp15        [V22,T07] (  3, 10   )     int  ->  rcx         single-def "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V23 tmp16        [V23    ] (  0,  0   )   byref  ->  zero-ref    "field V11._reference (fldOffset=0x0)" P-INDEP
 ;* V24 tmp17        [V24    ] (  0,  0   )     int  ->  zero-ref    "field V11._length (fldOffset=0x8)" P-INDEP
 ;* V25 tmp18        [V25    ] (  0,  0   )   byref  ->  zero-ref    "field V12._reference (fldOffset=0x0)" P-INDEP
 ;* V26 tmp19        [V26    ] (  0,  0   )     int  ->  zero-ref    "field V12._length (fldOffset=0x8)" P-INDEP
 ;* V27 tmp20        [V27    ] (  0,  0   )   byref  ->  zero-ref    "field V13._reference (fldOffset=0x0)" P-INDEP
 ;* V28 tmp21        [V28    ] (  0,  0   )     int  ->  zero-ref    "field V13._length (fldOffset=0x8)" P-INDEP
 ;* V29 tmp22        [V29    ] (  0,  0   )   byref  ->  zero-ref    "field V16._reference (fldOffset=0x0)" P-INDEP
 ;* V30 tmp23        [V30    ] (  0,  0   )     int  ->  zero-ref    "field V16._length (fldOffset=0x8)" P-INDEP
 ;* V31 tmp24        [V31    ] (  0,  0   )   byref  ->  zero-ref    "field V17._reference (fldOffset=0x0)" P-INDEP
 ;* V32 tmp25        [V32    ] (  0,  0   )     int  ->  zero-ref    "field V17._length (fldOffset=0x8)" P-INDEP
 ;* V33 tmp26        [V33    ] (  0,  0   )   byref  ->  zero-ref    "field V18._reference (fldOffset=0x0)" P-INDEP
 ;* V34 tmp27        [V34    ] (  0,  0   )     int  ->  zero-ref    "field V18._length (fldOffset=0x8)" P-INDEP
 ;  V35 rat0         [V35,T01] (  8, 34   )    long  ->  r11         "Widened IV V03"
 ;
 ; Lcl frame size = 0
 
 G_M9153_IG01:
        push     rbp
        push     r15
        push     rbx
        lea      rbp, [rsp+0x10]
 						;; size=9 bbWeight=1 PerfScore 3.50
 G_M9153_IG02:
        xor      eax, eax
        xor      r9d, r9d
        xor      r10d, r10d
        xor      r11d, r11d
        cmp      eax, ecx
        jge      G_M9153_IG11
        align    [0 bytes for IG03]
 						;; size=19 bbWeight=1 PerfScore 2.25
 G_M9153_IG03:
        lea      r9d, [r11+0x01]
        cmp      r9d, esi
        jae      G_M9153_IG13
        lea      r10d, [r11+0x01]
        mov      r9d, r10d
        movzx    r9, word  ptr [rdi+2*r9]
        cmp      r9d, 256
        jl       SHORT G_M9153_IG05
 						;; size=34 bbWeight=4 PerfScore 23.00
 G_M9153_IG04:
-       mov      r10d, 255
+       mov      r10d, -1
        jmp      SHORT G_M9153_IG06
 						;; size=8 bbWeight=2 PerfScore 4.50
 G_M9153_IG05:
        mov      r10d, r9d
        mov      r9, 0xD1FFAB1E      ; static handle
-       movzx    r10, byte  ptr [r9+r10]
-						;; size=18 bbWeight=2 PerfScore 5.00
+       movsx    r10, byte  ptr [r9+r10]
+						;; size=18 bbWeight=2 PerfScore 9.00
 G_M9153_IG06:
        mov      r9d, r10d
        cmp      r11d, esi
-       jae      G_M9153_IG13
+       jae      SHORT G_M9153_IG13
        movzx    r10, word  ptr [rdi+2*r11]
        cmp      r10d, 256
        jl       SHORT G_M9153_IG08
-						;; size=26 bbWeight=4 PerfScore 19.00
+						;; size=22 bbWeight=4 PerfScore 19.00
 G_M9153_IG07:
-       mov      ebx, 255
+       mov      ebx, -1
        jmp      SHORT G_M9153_IG09
 						;; size=7 bbWeight=2 PerfScore 4.50
 G_M9153_IG08:
        mov      r10d, r10d
        mov      rbx, 0xD1FFAB1E      ; static handle
-       movzx    rbx, byte  ptr [rbx+r10]
-						;; size=18 bbWeight=2 PerfScore 5.00
+       movsx    rbx, byte  ptr [rbx+r10]
+						;; size=18 bbWeight=2 PerfScore 9.00
 G_M9153_IG09:
        mov      r10d, ebx
        mov      ebx, r9d
        or       ebx, r10d
-       cmp      ebx, 255
-       je       SHORT G_M9153_IG11
-						;; size=17 bbWeight=4 PerfScore 8.00
+       jl       SHORT G_M9153_IG11
+						;; size=11 bbWeight=4 PerfScore 7.00
 G_M9153_IG10:
        lea      ebx, [rax+0x01]
        mov      eax, eax
        mov      r15d, r10d
        shl      r15d, 4
        or       r15d, r9d
        mov      byte  ptr [rdx+rax], r15b
        add      r11d, 2
        cmp      ebx, ecx
        mov      eax, ebx
        jl       G_M9153_IG03
 						;; size=33 bbWeight=8 PerfScore 36.00
 G_M9153_IG11:
        mov      eax, r11d
        lea      ecx, [rax+0x01]
-       cmp      r9d, 255
-       cmove    eax, ecx
+       test     r9d, r9d
+       cmovl    eax, ecx
        mov      dword ptr [r8], eax
        or       r9d, r10d
-       cmp      r9d, 255
-       setne    al
-       movzx    rax, al
-						;; size=35 bbWeight=1 PerfScore 4.00
+       mov      eax, r9d
+       not      eax
+       shr      eax, 31
+						;; size=26 bbWeight=1 PerfScore 3.50
 G_M9153_IG12:
        pop      rbx
        pop      r15
        pop      rbp
        ret      
 						;; size=5 bbWeight=1 PerfScore 2.50
 G_M9153_IG13:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 235, prolog size 9, PerfScore 117.25, instruction count 65, allocated bytes for code 235 (MethodHash=f030dc3e) for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
+; Total bytes of code 216, prolog size 9, PerfScore 123.75, instruction count 64, allocated bytes for code 216 (MethodHash=f030dc3e) for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
 ; ============================================================

-19 (-8.09 % of base) - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool

 ; Assembly listing for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; fully interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 4 single block inlinees; 6 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;* V00 arg0         [V00    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.ReadOnlySpan`1[char]>
 ;* V01 arg1         [V01    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.Span`1[byte]>
 ;  V02 arg2         [V02,T14] (  3,  3   )   byref  ->   r8         single-def
 ;  V03 loc0         [V03,T13] (  5,  5   )     int  ->  rax        
 ;  V04 loc1         [V04,T02] (  5, 26   )     int  ->  registers  
 ;  V05 loc2         [V05,T05] (  6, 19   )     int  ->   r9        
 ;  V06 loc3         [V06,T06] (  5, 18   )     int  ->  r10        
 ;# V07 OutArgs      [V07    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
 ;  V08 tmp1         [V08,T00] (  3, 48   )     int  ->  rax         "impSpillLclRefs"
 ;  V09 tmp2         [V09,T11] (  3,  8   )     int  ->  r10         "Inline return value spill temp"
 ;  V10 tmp3         [V10,T03] (  3, 20   )     int  ->   r9         "Inlining Arg"
-;* V11 tmp4         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[byte]>
-;* V12 tmp5         [V12    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V13 tmp6         [V13    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V11 tmp4         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[sbyte]>
+;* V12 tmp5         [V12    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V13 tmp6         [V13    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V14 tmp7         [V14,T12] (  3,  8   )     int  ->  rbx         "Inline return value spill temp"
 ;  V15 tmp8         [V15,T04] (  3, 20   )     int  ->  r10         "Inlining Arg"
-;* V16 tmp9         [V16    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[byte]>
-;* V17 tmp10        [V17    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V18 tmp11        [V18    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V16 tmp9         [V16    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[sbyte]>
+;* V17 tmp10        [V17    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V18 tmp11        [V18    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V19 tmp12        [V19,T08] (  3,  9   )   byref  ->  rdi         single-def "field V00._reference (fldOffset=0x0)" P-INDEP
 ;  V20 tmp13        [V20,T09] (  3,  9   )     int  ->  rsi         single-def "field V00._length (fldOffset=0x8)" P-INDEP
 ;  V21 tmp14        [V21,T10] (  2,  9   )   byref  ->  rdx         single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;  V22 tmp15        [V22,T07] (  3, 10   )     int  ->  rcx         single-def "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V23 tmp16        [V23    ] (  0,  0   )   byref  ->  zero-ref    "field V11._reference (fldOffset=0x0)" P-INDEP
 ;* V24 tmp17        [V24    ] (  0,  0   )     int  ->  zero-ref    "field V11._length (fldOffset=0x8)" P-INDEP
 ;* V25 tmp18        [V25    ] (  0,  0   )   byref  ->  zero-ref    "field V12._reference (fldOffset=0x0)" P-INDEP
 ;* V26 tmp19        [V26    ] (  0,  0   )     int  ->  zero-ref    "field V12._length (fldOffset=0x8)" P-INDEP
 ;* V27 tmp20        [V27    ] (  0,  0   )   byref  ->  zero-ref    "field V13._reference (fldOffset=0x0)" P-INDEP
 ;* V28 tmp21        [V28    ] (  0,  0   )     int  ->  zero-ref    "field V13._length (fldOffset=0x8)" P-INDEP
 ;* V29 tmp22        [V29    ] (  0,  0   )   byref  ->  zero-ref    "field V16._reference (fldOffset=0x0)" P-INDEP
 ;* V30 tmp23        [V30    ] (  0,  0   )     int  ->  zero-ref    "field V16._length (fldOffset=0x8)" P-INDEP
 ;* V31 tmp24        [V31    ] (  0,  0   )   byref  ->  zero-ref    "field V17._reference (fldOffset=0x0)" P-INDEP
 ;* V32 tmp25        [V32    ] (  0,  0   )     int  ->  zero-ref    "field V17._length (fldOffset=0x8)" P-INDEP
 ;* V33 tmp26        [V33    ] (  0,  0   )   byref  ->  zero-ref    "field V18._reference (fldOffset=0x0)" P-INDEP
 ;* V34 tmp27        [V34    ] (  0,  0   )     int  ->  zero-ref    "field V18._length (fldOffset=0x8)" P-INDEP
 ;  V35 rat0         [V35,T01] (  8, 34   )    long  ->  r11         "Widened IV V03"
 ;
 ; Lcl frame size = 0
 
 G_M9153_IG01:
        push     rbp
        push     r15
        push     rbx
        lea      rbp, [rsp+0x10]
 						;; size=9 bbWeight=1 PerfScore 3.50
 G_M9153_IG02:
        xor      eax, eax
        xor      r9d, r9d
        xor      r10d, r10d
        xor      r11d, r11d
        cmp      eax, ecx
        jge      G_M9153_IG11
        align    [0 bytes for IG03]
 						;; size=19 bbWeight=1 PerfScore 2.25
 G_M9153_IG03:
        lea      r9d, [r11+0x01]
        cmp      r9d, esi
        jae      G_M9153_IG13
        lea      r10d, [r11+0x01]
        mov      r9d, r10d
        movzx    r9, word  ptr [rdi+2*r9]
        cmp      r9d, 256
        jl       SHORT G_M9153_IG05
 						;; size=34 bbWeight=4 PerfScore 23.00
 G_M9153_IG04:
-       mov      r10d, 255
+       mov      r10d, -1
        jmp      SHORT G_M9153_IG06
 						;; size=8 bbWeight=2 PerfScore 4.50
 G_M9153_IG05:
        mov      r10d, r9d
        mov      r9, 0xD1FFAB1E      ; static handle
-       movzx    r10, byte  ptr [r9+r10]
-						;; size=18 bbWeight=2 PerfScore 5.00
+       movsx    r10, byte  ptr [r9+r10]
+						;; size=18 bbWeight=2 PerfScore 9.00
 G_M9153_IG06:
        mov      r9d, r10d
        cmp      r11d, esi
-       jae      G_M9153_IG13
+       jae      SHORT G_M9153_IG13
        movzx    r10, word  ptr [rdi+2*r11]
        cmp      r10d, 256
        jl       SHORT G_M9153_IG08
-						;; size=26 bbWeight=4 PerfScore 19.00
+						;; size=22 bbWeight=4 PerfScore 19.00
 G_M9153_IG07:
-       mov      ebx, 255
+       mov      ebx, -1
        jmp      SHORT G_M9153_IG09
 						;; size=7 bbWeight=2 PerfScore 4.50
 G_M9153_IG08:
        mov      r10d, r10d
        mov      rbx, 0xD1FFAB1E      ; static handle
-       movzx    rbx, byte  ptr [rbx+r10]
-						;; size=18 bbWeight=2 PerfScore 5.00
+       movsx    rbx, byte  ptr [rbx+r10]
+						;; size=18 bbWeight=2 PerfScore 9.00
 G_M9153_IG09:
        mov      r10d, ebx
        mov      ebx, r9d
        or       ebx, r10d
-       cmp      ebx, 255
-       je       SHORT G_M9153_IG11
-						;; size=17 bbWeight=4 PerfScore 8.00
+       jl       SHORT G_M9153_IG11
+						;; size=11 bbWeight=4 PerfScore 7.00
 G_M9153_IG10:
        lea      ebx, [rax+0x01]
        mov      eax, eax
        mov      r15d, r10d
        shl      r15d, 4
        or       r15d, r9d
        mov      byte  ptr [rdx+rax], r15b
        add      r11d, 2
        cmp      ebx, ecx
        mov      eax, ebx
        jl       G_M9153_IG03
 						;; size=33 bbWeight=8 PerfScore 36.00
 G_M9153_IG11:
        mov      eax, r11d
        lea      ecx, [rax+0x01]
-       cmp      r9d, 255
-       cmove    eax, ecx
+       test     r9d, r9d
+       cmovl    eax, ecx
        mov      dword ptr [r8], eax
        or       r9d, r10d
-       cmp      r9d, 255
-       setne    al
-       movzx    rax, al
-						;; size=35 bbWeight=1 PerfScore 4.00
+       mov      eax, r9d
+       not      eax
+       shr      eax, 31
+						;; size=26 bbWeight=1 PerfScore 3.50
 G_M9153_IG12:
        pop      rbx
        pop      r15
        pop      rbp
        ret      
 						;; size=5 bbWeight=1 PerfScore 2.50
 G_M9153_IG13:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 235, prolog size 9, PerfScore 117.25, instruction count 65, allocated bytes for code 235 (MethodHash=f030dc3e) for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
+; Total bytes of code 216, prolog size 9, PerfScore 123.75, instruction count 64, allocated bytes for code 216 (MethodHash=f030dc3e) for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
 ; ============================================================

-19 (-8.09 % of base) - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool

 ; Assembly listing for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; fully interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 4 single block inlinees; 6 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;* V00 arg0         [V00    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.ReadOnlySpan`1[char]>
 ;* V01 arg1         [V01    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.Span`1[byte]>
 ;  V02 arg2         [V02,T14] (  3,  3   )   byref  ->   r8         single-def
 ;  V03 loc0         [V03,T13] (  5,  5   )     int  ->  rax        
 ;  V04 loc1         [V04,T02] (  5, 26   )     int  ->  registers  
 ;  V05 loc2         [V05,T05] (  6, 19   )     int  ->   r9        
 ;  V06 loc3         [V06,T06] (  5, 18   )     int  ->  r10        
 ;# V07 OutArgs      [V07    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
 ;  V08 tmp1         [V08,T00] (  3, 48   )     int  ->  rax         "impSpillLclRefs"
 ;  V09 tmp2         [V09,T11] (  3,  8   )     int  ->  r10         "Inline return value spill temp"
 ;  V10 tmp3         [V10,T03] (  3, 20   )     int  ->   r9         "Inlining Arg"
-;* V11 tmp4         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[byte]>
-;* V12 tmp5         [V12    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V13 tmp6         [V13    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V11 tmp4         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[sbyte]>
+;* V12 tmp5         [V12    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V13 tmp6         [V13    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V14 tmp7         [V14,T12] (  3,  8   )     int  ->  rbx         "Inline return value spill temp"
 ;  V15 tmp8         [V15,T04] (  3, 20   )     int  ->  r10         "Inlining Arg"
-;* V16 tmp9         [V16    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[byte]>
-;* V17 tmp10        [V17    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V18 tmp11        [V18    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V16 tmp9         [V16    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[sbyte]>
+;* V17 tmp10        [V17    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V18 tmp11        [V18    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V19 tmp12        [V19,T08] (  3,  9   )   byref  ->  rdi         single-def "field V00._reference (fldOffset=0x0)" P-INDEP
 ;  V20 tmp13        [V20,T09] (  3,  9   )     int  ->  rsi         single-def "field V00._length (fldOffset=0x8)" P-INDEP
 ;  V21 tmp14        [V21,T10] (  2,  9   )   byref  ->  rdx         single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;  V22 tmp15        [V22,T07] (  3, 10   )     int  ->  rcx         single-def "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V23 tmp16        [V23    ] (  0,  0   )   byref  ->  zero-ref    "field V11._reference (fldOffset=0x0)" P-INDEP
 ;* V24 tmp17        [V24    ] (  0,  0   )     int  ->  zero-ref    "field V11._length (fldOffset=0x8)" P-INDEP
 ;* V25 tmp18        [V25    ] (  0,  0   )   byref  ->  zero-ref    "field V12._reference (fldOffset=0x0)" P-INDEP
 ;* V26 tmp19        [V26    ] (  0,  0   )     int  ->  zero-ref    "field V12._length (fldOffset=0x8)" P-INDEP
 ;* V27 tmp20        [V27    ] (  0,  0   )   byref  ->  zero-ref    "field V13._reference (fldOffset=0x0)" P-INDEP
 ;* V28 tmp21        [V28    ] (  0,  0   )     int  ->  zero-ref    "field V13._length (fldOffset=0x8)" P-INDEP
 ;* V29 tmp22        [V29    ] (  0,  0   )   byref  ->  zero-ref    "field V16._reference (fldOffset=0x0)" P-INDEP
 ;* V30 tmp23        [V30    ] (  0,  0   )     int  ->  zero-ref    "field V16._length (fldOffset=0x8)" P-INDEP
 ;* V31 tmp24        [V31    ] (  0,  0   )   byref  ->  zero-ref    "field V17._reference (fldOffset=0x0)" P-INDEP
 ;* V32 tmp25        [V32    ] (  0,  0   )     int  ->  zero-ref    "field V17._length (fldOffset=0x8)" P-INDEP
 ;* V33 tmp26        [V33    ] (  0,  0   )   byref  ->  zero-ref    "field V18._reference (fldOffset=0x0)" P-INDEP
 ;* V34 tmp27        [V34    ] (  0,  0   )     int  ->  zero-ref    "field V18._length (fldOffset=0x8)" P-INDEP
 ;  V35 rat0         [V35,T01] (  8, 34   )    long  ->  r11         "Widened IV V03"
 ;
 ; Lcl frame size = 0
 
 G_M9153_IG01:
        push     rbp
        push     r15
        push     rbx
        lea      rbp, [rsp+0x10]
 						;; size=9 bbWeight=1 PerfScore 3.50
 G_M9153_IG02:
        xor      eax, eax
        xor      r9d, r9d
        xor      r10d, r10d
        xor      r11d, r11d
        cmp      eax, ecx
        jge      G_M9153_IG11
        align    [0 bytes for IG03]
 						;; size=19 bbWeight=1 PerfScore 2.25
 G_M9153_IG03:
        lea      r9d, [r11+0x01]
        cmp      r9d, esi
        jae      G_M9153_IG13
        lea      r10d, [r11+0x01]
        mov      r9d, r10d
        movzx    r9, word  ptr [rdi+2*r9]
        cmp      r9d, 256
        jl       SHORT G_M9153_IG05
 						;; size=34 bbWeight=4 PerfScore 23.00
 G_M9153_IG04:
-       mov      r10d, 255
+       mov      r10d, -1
        jmp      SHORT G_M9153_IG06
 						;; size=8 bbWeight=2 PerfScore 4.50
 G_M9153_IG05:
        mov      r10d, r9d
        mov      r9, 0xD1FFAB1E      ; static handle
-       movzx    r10, byte  ptr [r9+r10]
-						;; size=18 bbWeight=2 PerfScore 5.00
+       movsx    r10, byte  ptr [r9+r10]
+						;; size=18 bbWeight=2 PerfScore 9.00
 G_M9153_IG06:
        mov      r9d, r10d
        cmp      r11d, esi
-       jae      G_M9153_IG13
+       jae      SHORT G_M9153_IG13
        movzx    r10, word  ptr [rdi+2*r11]
        cmp      r10d, 256
        jl       SHORT G_M9153_IG08
-						;; size=26 bbWeight=4 PerfScore 19.00
+						;; size=22 bbWeight=4 PerfScore 19.00
 G_M9153_IG07:
-       mov      ebx, 255
+       mov      ebx, -1
        jmp      SHORT G_M9153_IG09
 						;; size=7 bbWeight=2 PerfScore 4.50
 G_M9153_IG08:
        mov      r10d, r10d
        mov      rbx, 0xD1FFAB1E      ; static handle
-       movzx    rbx, byte  ptr [rbx+r10]
-						;; size=18 bbWeight=2 PerfScore 5.00
+       movsx    rbx, byte  ptr [rbx+r10]
+						;; size=18 bbWeight=2 PerfScore 9.00
 G_M9153_IG09:
        mov      r10d, ebx
        mov      ebx, r9d
        or       ebx, r10d
-       cmp      ebx, 255
-       je       SHORT G_M9153_IG11
-						;; size=17 bbWeight=4 PerfScore 8.00
+       jl       SHORT G_M9153_IG11
+						;; size=11 bbWeight=4 PerfScore 7.00
 G_M9153_IG10:
        lea      ebx, [rax+0x01]
        mov      eax, eax
        mov      r15d, r10d
        shl      r15d, 4
        or       r15d, r9d
        mov      byte  ptr [rdx+rax], r15b
        add      r11d, 2
        cmp      ebx, ecx
        mov      eax, ebx
        jl       G_M9153_IG03
 						;; size=33 bbWeight=8 PerfScore 36.00
 G_M9153_IG11:
        mov      eax, r11d
        lea      ecx, [rax+0x01]
-       cmp      r9d, 255
-       cmove    eax, ecx
+       test     r9d, r9d
+       cmovl    eax, ecx
        mov      dword ptr [r8], eax
        or       r9d, r10d
-       cmp      r9d, 255
-       setne    al
-       movzx    rax, al
-						;; size=35 bbWeight=1 PerfScore 4.00
+       mov      eax, r9d
+       not      eax
+       shr      eax, 31
+						;; size=26 bbWeight=1 PerfScore 3.50
 G_M9153_IG12:
        pop      rbx
        pop      r15
        pop      rbp
        ret      
 						;; size=5 bbWeight=1 PerfScore 2.50
 G_M9153_IG13:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 235, prolog size 9, PerfScore 117.25, instruction count 65, allocated bytes for code 235 (MethodHash=f030dc3e) for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
+; Total bytes of code 216, prolog size 9, PerfScore 123.75, instruction count 64, allocated bytes for code 216 (MethodHash=f030dc3e) for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
 ; ============================================================

-19 (-8.09 % of base) - System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool

 ; Assembly listing for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
 ; Emitting BLENDED_CODE for generic X64 + VEX + EVEX on Unix
 ; FullOpts code
 ; optimized code
 ; rbp based frame
 ; fully interruptible
 ; No PGO data
 ; 0 inlinees with PGO data; 4 single block inlinees; 6 inlinees without PGO data
 ; Final local variable assignments
 ;
 ;* V00 arg0         [V00    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.ReadOnlySpan`1[char]>
 ;* V01 arg1         [V01    ] (  0,  0   )  struct (16) zero-ref    multireg-arg ld-addr-op single-def <System.Span`1[byte]>
 ;  V02 arg2         [V02,T14] (  3,  3   )   byref  ->   r8         single-def
 ;  V03 loc0         [V03,T13] (  5,  5   )     int  ->  rax        
 ;  V04 loc1         [V04,T02] (  5, 26   )     int  ->  registers  
 ;  V05 loc2         [V05,T05] (  6, 19   )     int  ->   r9        
 ;  V06 loc3         [V06,T06] (  5, 18   )     int  ->  r10        
 ;# V07 OutArgs      [V07    ] (  1,  1   )  struct ( 0) [rsp+0x00]  do-not-enreg[XS] addr-exposed "OutgoingArgSpace" <Empty>
 ;  V08 tmp1         [V08,T00] (  3, 48   )     int  ->  rax         "impSpillLclRefs"
 ;  V09 tmp2         [V09,T11] (  3,  8   )     int  ->  r10         "Inline return value spill temp"
 ;  V10 tmp3         [V10,T03] (  3, 20   )     int  ->   r9         "Inlining Arg"
-;* V11 tmp4         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[byte]>
-;* V12 tmp5         [V12    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V13 tmp6         [V13    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V11 tmp4         [V11    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[sbyte]>
+;* V12 tmp5         [V12    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V13 tmp6         [V13    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V14 tmp7         [V14,T12] (  3,  8   )     int  ->  rbx         "Inline return value spill temp"
 ;  V15 tmp8         [V15,T04] (  3, 20   )     int  ->  r10         "Inlining Arg"
-;* V16 tmp9         [V16    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[byte]>
-;* V17 tmp10        [V17    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
-;* V18 tmp11        [V18    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[byte]>
+;* V16 tmp9         [V16    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "Inline stloc first use temp" <System.ReadOnlySpan`1[sbyte]>
+;* V17 tmp10        [V17    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
+;* V18 tmp11        [V18    ] (  0,  0   )  struct (16) zero-ref    ld-addr-op "NewObj constructor temp" <System.ReadOnlySpan`1[sbyte]>
 ;  V19 tmp12        [V19,T08] (  3,  9   )   byref  ->  rdi         single-def "field V00._reference (fldOffset=0x0)" P-INDEP
 ;  V20 tmp13        [V20,T09] (  3,  9   )     int  ->  rsi         single-def "field V00._length (fldOffset=0x8)" P-INDEP
 ;  V21 tmp14        [V21,T10] (  2,  9   )   byref  ->  rdx         single-def "field V01._reference (fldOffset=0x0)" P-INDEP
 ;  V22 tmp15        [V22,T07] (  3, 10   )     int  ->  rcx         single-def "field V01._length (fldOffset=0x8)" P-INDEP
 ;* V23 tmp16        [V23    ] (  0,  0   )   byref  ->  zero-ref    "field V11._reference (fldOffset=0x0)" P-INDEP
 ;* V24 tmp17        [V24    ] (  0,  0   )     int  ->  zero-ref    "field V11._length (fldOffset=0x8)" P-INDEP
 ;* V25 tmp18        [V25    ] (  0,  0   )   byref  ->  zero-ref    "field V12._reference (fldOffset=0x0)" P-INDEP
 ;* V26 tmp19        [V26    ] (  0,  0   )     int  ->  zero-ref    "field V12._length (fldOffset=0x8)" P-INDEP
 ;* V27 tmp20        [V27    ] (  0,  0   )   byref  ->  zero-ref    "field V13._reference (fldOffset=0x0)" P-INDEP
 ;* V28 tmp21        [V28    ] (  0,  0   )     int  ->  zero-ref    "field V13._length (fldOffset=0x8)" P-INDEP
 ;* V29 tmp22        [V29    ] (  0,  0   )   byref  ->  zero-ref    "field V16._reference (fldOffset=0x0)" P-INDEP
 ;* V30 tmp23        [V30    ] (  0,  0   )     int  ->  zero-ref    "field V16._length (fldOffset=0x8)" P-INDEP
 ;* V31 tmp24        [V31    ] (  0,  0   )   byref  ->  zero-ref    "field V17._reference (fldOffset=0x0)" P-INDEP
 ;* V32 tmp25        [V32    ] (  0,  0   )     int  ->  zero-ref    "field V17._length (fldOffset=0x8)" P-INDEP
 ;* V33 tmp26        [V33    ] (  0,  0   )   byref  ->  zero-ref    "field V18._reference (fldOffset=0x0)" P-INDEP
 ;* V34 tmp27        [V34    ] (  0,  0   )     int  ->  zero-ref    "field V18._length (fldOffset=0x8)" P-INDEP
 ;  V35 rat0         [V35,T01] (  8, 34   )    long  ->  r11         "Widened IV V03"
 ;
 ; Lcl frame size = 0
 
 G_M9153_IG01:
        push     rbp
        push     r15
        push     rbx
        lea      rbp, [rsp+0x10]
 						;; size=9 bbWeight=1 PerfScore 3.50
 G_M9153_IG02:
        xor      eax, eax
        xor      r9d, r9d
        xor      r10d, r10d
        xor      r11d, r11d
        cmp      eax, ecx
        jge      G_M9153_IG11
        align    [0 bytes for IG03]
 						;; size=19 bbWeight=1 PerfScore 2.25
 G_M9153_IG03:
        lea      r9d, [r11+0x01]
        cmp      r9d, esi
        jae      G_M9153_IG13
        lea      r10d, [r11+0x01]
        mov      r9d, r10d
        movzx    r9, word  ptr [rdi+2*r9]
        cmp      r9d, 256
        jl       SHORT G_M9153_IG05
 						;; size=34 bbWeight=4 PerfScore 23.00
 G_M9153_IG04:
-       mov      r10d, 255
+       mov      r10d, -1
        jmp      SHORT G_M9153_IG06
 						;; size=8 bbWeight=2 PerfScore 4.50
 G_M9153_IG05:
        mov      r10d, r9d
        mov      r9, 0xD1FFAB1E      ; static handle
-       movzx    r10, byte  ptr [r9+r10]
-						;; size=18 bbWeight=2 PerfScore 5.00
+       movsx    r10, byte  ptr [r9+r10]
+						;; size=18 bbWeight=2 PerfScore 9.00
 G_M9153_IG06:
        mov      r9d, r10d
        cmp      r11d, esi
-       jae      G_M9153_IG13
+       jae      SHORT G_M9153_IG13
        movzx    r10, word  ptr [rdi+2*r11]
        cmp      r10d, 256
        jl       SHORT G_M9153_IG08
-						;; size=26 bbWeight=4 PerfScore 19.00
+						;; size=22 bbWeight=4 PerfScore 19.00
 G_M9153_IG07:
-       mov      ebx, 255
+       mov      ebx, -1
        jmp      SHORT G_M9153_IG09
 						;; size=7 bbWeight=2 PerfScore 4.50
 G_M9153_IG08:
        mov      r10d, r10d
        mov      rbx, 0xD1FFAB1E      ; static handle
-       movzx    rbx, byte  ptr [rbx+r10]
-						;; size=18 bbWeight=2 PerfScore 5.00
+       movsx    rbx, byte  ptr [rbx+r10]
+						;; size=18 bbWeight=2 PerfScore 9.00
 G_M9153_IG09:
        mov      r10d, ebx
        mov      ebx, r9d
        or       ebx, r10d
-       cmp      ebx, 255
-       je       SHORT G_M9153_IG11
-						;; size=17 bbWeight=4 PerfScore 8.00
+       jl       SHORT G_M9153_IG11
+						;; size=11 bbWeight=4 PerfScore 7.00
 G_M9153_IG10:
        lea      ebx, [rax+0x01]
        mov      eax, eax
        mov      r15d, r10d
        shl      r15d, 4
        or       r15d, r9d
        mov      byte  ptr [rdx+rax], r15b
        add      r11d, 2
        cmp      ebx, ecx
        mov      eax, ebx
        jl       G_M9153_IG03
 						;; size=33 bbWeight=8 PerfScore 36.00
 G_M9153_IG11:
        mov      eax, r11d
        lea      ecx, [rax+0x01]
-       cmp      r9d, 255
-       cmove    eax, ecx
+       test     r9d, r9d
+       cmovl    eax, ecx
        mov      dword ptr [r8], eax
        or       r9d, r10d
-       cmp      r9d, 255
-       setne    al
-       movzx    rax, al
-						;; size=35 bbWeight=1 PerfScore 4.00
+       mov      eax, r9d
+       not      eax
+       shr      eax, 31
+						;; size=26 bbWeight=1 PerfScore 3.50
 G_M9153_IG12:
        pop      rbx
        pop      r15
        pop      rbp
        ret      
 						;; size=5 bbWeight=1 PerfScore 2.50
 G_M9153_IG13:
        call     CORINFO_HELP_RNGCHKFAIL
        int3     
 						;; size=6 bbWeight=0 PerfScore 0.00
 
-; Total bytes of code 235, prolog size 9, PerfScore 117.25, instruction count 65, allocated bytes for code 235 (MethodHash=f030dc3e) for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
+; Total bytes of code 216, prolog size 9, PerfScore 123.75, instruction count 64, allocated bytes for code 216 (MethodHash=f030dc3e) for method System.HexConverter:TryDecodeFromUtf16_Scalar(System.ReadOnlySpan`1[char],System.Span`1[byte],byref):bool (FullOpts)
 ; ============================================================

Note: some changes were skipped as they were too large to fit into a comment.

Larger list of diffs: https://gist.github.com/MihuBot/b0dc3274fa06cba670d8f431b2349355

[MihuBot]

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