Temporarily disable arm64-intrin. UTF-16 validation (#42052)

GrabYourPitchforks · web-flow · commit 0923e83c58c9 · 2020-09-10T04:06:35.000-07:00
diff --git a/src/libraries/System.Private.CoreLib/src/System/Text/Unicode/Utf16Utility.Validation.cs b/src/libraries/System.Private.CoreLib/src/System/Text/Unicode/Utf16Utility.Validation.cs
@@ -79,7 +79,11 @@ static Utf16Utility()
             long tempUtf8CodeUnitCountAdjustment = 0;
             int tempScalarCountAdjustment = 0;
 
-            if ((AdvSimd.Arm64.IsSupported && BitConverter.IsLittleEndian) || Sse2.IsSupported)
+            // Per https://github.com/dotnet/runtime/issues/41699, temporarily disabling
+            // ARM64-intrinsicified code paths. ARM64 platforms may still use the vectorized
+            // non-intrinsicified 'else' block below.
+
+            if (/* (AdvSimd.Arm64.IsSupported && BitConverter.IsLittleEndian) || */ Sse2.IsSupported)
             {
                 if (inputLength >= Vector128<ushort>.Count)
                 {

Original file line number	Diff line number	Diff line change
`@@ -79,7 +79,11 @@ static Utf16Utility()`
`79`	`79`	`long tempUtf8CodeUnitCountAdjustment = 0;`
`80`	`80`	`int tempScalarCountAdjustment = 0;`
`81`	`81`
`82`		`- if ((AdvSimd.Arm64.IsSupported && BitConverter.IsLittleEndian) \|\| Sse2.IsSupported)`
	`82`	`+ // Per https://github.com/dotnet/runtime/issues/41699, temporarily disabling`
	`83`	`+ // ARM64-intrinsicified code paths. ARM64 platforms may still use the vectorized`
	`84`	`+ // non-intrinsicified 'else' block below.`
	`85`	`+`
	`86`	`+ if (/* (AdvSimd.Arm64.IsSupported && BitConverter.IsLittleEndian) \|\| */ Sse2.IsSupported)`
`83`	`87`	`{`
`84`	`88`	`if (inputLength >= Vector128<ushort>.Count)`
`85`	`89`	`{`