[libs][iOS] AdvSimdEncode hits PlatformNotSupportedException #96828
Description
Description
After #95513 was merged, some tests that eventually invoke EncodeToUtf8 such as
PlatformNotSupportedException on iOS/tvOS arm64 lanes.
Test collection for System.Collections.Tests.PriorityQueue_PropertyTests
Test name: System.Collections.Tests.PriorityQueue_PropertyTests.HeapSort_Heapify_String
Exception messages: System.PlatformNotSupportedException :
Exception stack traces: at System.Runtime.Intrinsics.Arm.AdvSimd.Arm64.LoadVector128x3AndUnzip(Byte* address)
at System.Buffers.Text.Base64.EncodeToUtf8(ReadOnlySpan`1 bytes, Span`1 utf8, Int32& bytesConsumed, Int32& bytesWritten, Boolean isFinalBlock)
at System.Convert.ToBase64CharsLargeNoLineBreaks(ReadOnlySpan`1 bytes, Span`1 chars, Int32 charLengthRequired)
at System.Convert.ToBase64String(ReadOnlySpan`1 bytes, Base64FormattingOptions options)
at System.Convert.ToBase64String(Byte[] inArray)
at System.Collections.Tests.PriorityQueue_PropertyTests.GenString(Random random)
at System.Collections.Tests.PriorityQueue_PropertyTests.GenArray[String](Func`2 genElement, Random random)
at System.Collections.Tests.PriorityQueue_PropertyTests.<>c.<GetRandomStringArrays>b__16_0(Random random)
at System.Collections.Tests.PriorityQueue_PropertyTests.<GenerateMemberData>d__18`1[[System.String[], System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
at System.Linq.Enumerable.SelectEnumerableIterator`2[[System.Object, System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Object[], System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
It looks like LoadVector128x3AndUnzip is possibly the culprit, as #84510 doesn't seem to account for mono.
Reproduction Steps
On OSX with an iOS device
./build.sh -s mono+libs -os ios -arch arm64 -c debug
./dotnet.sh build src/libraries/System.Collections/tests/System.Collections.Tests.csproj /t:Test /p:TargetOS=ios /p:TargetArchitecture=arm64 /p:Configuration=Debug /p:DevTeamProvisioning=<dev team provisioning ID> /p:XunitMethodName=System.Collections.Tests.PriorityQueue_PropertyTests.HeapSort_Heapify_String /p:MonoEnableLLVM=true /p:RunAOTCompilation=trueExpected behavior
Test doesn't fail with PlatformNotSupportedException
Actual behavior
Various tests eventually that end up calling AdvSimd.Arm64.LoadVector128x3AndUnzip on iOS/tvOS fail with PlatformNotSupportedException
Regression?
Yes
Known Workarounds
No-op AdvSimdEncode on mono
Configuration
No response
Other information
No response