Implement SVE2 Rounded Arithmetic Intrinsics

[snickolls-arm]

Includes:

• AddRoundedHighNarrowingEven, AddRoundedHighNarrowingOdd
• FusedAddRoundedHalving
• SubtractRoundedHighNarrowingEven, SubtractRoundedHighNarrowingOdd

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[a74nh]

@amanasifkhalid

[amanasifkhalid]

Preliminary pass LGTM, though CI is blocked by the merge conflicts I introduced (sorry about that)

[MichalStrehovsky]

@tannergooding what would be the best way to disable these tests on native AOT? I don't want to disable the entire project but whatever calls into the codepaths with dynamic keyword is unsupportable. Outerloop is failing with stacks like

System.ArgumentNullException: Value cannot be null. (Parameter 'key')
   at System.Collections.Generic.Dictionary`2.TryInsert(TKey key, TValue value, InsertionBehavior behavior) + 0x3c8
   at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value) + 0x10
   at Microsoft.CSharp.RuntimeBinder.ExpressionTreeCallRewriter.VisitSAVE(ExprBinOp) + 0x5c
   at Microsoft.CSharp.RuntimeBinder.Semantics.ExprVisitorBase.Dispatch(Expr) + 0x408
   at Microsoft.CSharp.RuntimeBinder.ExpressionTreeCallRewriter.Rewrite(ExprBinOp, Expression[]) + 0x6c
   at Microsoft.CSharp.RuntimeBinder.RuntimeBinder.BindCore(ICSharpBinder, Expression[], DynamicMetaObject[], DynamicMetaObject&) + 0x1d4
   at Microsoft.CSharp.RuntimeBinder.RuntimeBinder.Bind(ICSharpBinder, Expression[], DynamicMetaObject[], DynamicMetaObject&) + 0x58
   at Microsoft.CSharp.RuntimeBinder.BinderHelper.Bind(ICSharpBinder, RuntimeBinder, DynamicMetaObject[], IEnumerable`1, DynamicMetaObject) + 0x490
   at System.Dynamic.DynamicMetaObjectBinder.Bind(Object[], ReadOnlyCollection`1, LabelTarget) + 0x148
   at System.Runtime.CompilerServices.CallSiteBinder.BindCore[T](CallSite`1, Object[]) + 0x94
   at HardwareIntrinsics_Arm_ro!<BaseAddress>+0x3e90d4c
   at System.Reflection.DynamicInvokeInfo.InvokeWithFewArguments(IntPtr, Byte&, Byte&, Object[], BinderBundle, Boolean) + 0xd0
--- End of stack trace from previous location ---
   at System.Linq.Expressions.Interpreter.ExceptionHelpers.UnwrapAndRethrow(TargetInvocationException) + 0x18
   at System.Linq.Expressions.Interpreter.MethodInfoCallInstruction.Run(InterpretedFrame) + 0x1cc
   at System.Linq.Expressions.Interpreter.Interpreter.Run(InterpretedFrame) + 0x48
   at System.Linq.Expressions.Interpreter.LightLambda.Run(Object[] arguments) + 0x8c
   at HardwareIntrinsics_Arm_ro!<BaseAddress>+0x3ce7ac0
   at JIT.HardwareIntrinsics.Arm.Helpers.AddRoundedHighNarrowing[W,N](W op1, W op2) + 0xa4
   at JIT.HardwareIntrinsics.Arm._AdvSimd.SimpleBinaryOpTest__AddRoundedHighNarrowingLower_Vector64_Byte.ValidateResult(UInt16[] left, UInt16[] right, Byte[] result, String method) + 0x90
   at JIT.HardwareIntrinsics.Arm._AdvSimd.Program.AddRoundedHighNarrowingLower_Vector64_Byte() + 0x3c
   at Program.<<Main>$>g__TestExecutor987|0_988(StreamWriter tempLogSw, StreamWriter statsCsvSw, Program.<>c__DisplayClass0_0&) + 0x114

[a74nh]

@tannergooding what would be the best way to disable these tests on native AOT? I don't want to disable the entire project but whatever calls into the codepaths with dynamic keyword is unsupportable. Outerloop is failing with stacks like

Given AdvSimd works on AOT then we definitely should be testing on it. @snickolls-arm could you take a look at removing the dynamic keyword from this file.

[amanasifkhalid]

could you take a look at removing the dynamic keyword from this file.

For cases like this, I think you can use Convert.ToUInt64() to do the cast without dynamic.