Explore adding an ISimdVector<TSelf, T> interface

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -920,7 +920,9 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\UnmanagedType.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\VarEnum.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\VariantWrapper.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\Intrinsics\ISimdVector_2.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\Intrinsics\Scalar.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\Intrinsics\SimdVectorExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\Intrinsics\Vector128.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\Intrinsics\Vector128_1.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\Intrinsics\Vector128DebugView_1.cs" />

src/libraries/System.Private.CoreLib/src/System/Runtime/Intrinsics/SimdVectorExtensions.cs

@@ -0,0 +1,122 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Runtime.Intrinsics
+{
+    internal static class SimdVectorExtensions
+    {
+        /// <summary>Copies a vector to a given array.</summary>
+        /// <typeparam name="TVector">The type of the vector.</typeparam>
+        /// <typeparam name="T">The type of the elements in the vector.</typeparam>
+        /// <param name="vector">The vector to be copied.</param>
+        /// <param name="destination">The array to which <paramref name="vector" /> is copied.</param>
+        /// <exception cref="ArgumentException">The length of <paramref name="destination" /> is less than <see cref="ISimdVector{TVector, T}.Count" />.</exception>
+        /// <exception cref="NullReferenceException"><paramref name="destination" /> is <c>null</c>.</exception>
+        /// <exception cref="NotSupportedException">The type of the elements in the vector (<typeparamref name="T" />) is not supported.</exception>
+        public static void CopyTo<TVector, T>(this TVector vector, T[] destination)
+            where TVector : unmanaged, ISimdVector<TVector, T>
+            where T : struct
+        {
+            TVector.CopyTo(vector, destination);
+        }
+
+        /// <summary>Copies a vector to a given array starting at the specified index.</summary>
+        /// <typeparam name="TVector">The type of the vector.</typeparam>
+        /// <typeparam name="T">The type of the elements in the vector.</typeparam>
+        /// <param name="vector">The vector to be copied.</param>
+        /// <param name="destination">The array to which <paramref name="vector" /> is copied.</param>
+        /// <param name="startIndex">The starting index of <paramref name="destination" /> which <paramref name="vector" /> will be copied to.</param>
+        /// <exception cref="ArgumentException">The length of <paramref name="destination" /> is less than <see cref="ISimdVector{TVector, T}.Count" />.</exception>
+        /// <exception cref="ArgumentOutOfRangeException"><paramref name="startIndex" /> is negative or greater than the length of <paramref name="destination" />.</exception>
+        /// <exception cref="NullReferenceException"><paramref name="destination" /> is <c>null</c>.</exception>
+        /// <exception cref="NotSupportedException">The type of the elements in the vector (<typeparamref name="T" />) is not supported.</exception>
+        public static void CopyTo<TVector, T>(this TVector vector, T[] destination, int startIndex)
+            where TVector : unmanaged, ISimdVector<TVector, T>
+            where T : struct
+        {
+            TVector.CopyTo(vector, destination, startIndex);
+        }
+
+        /// <summary>Copies a vector to a given span.</summary>
+        /// <typeparam name="TVector">The type of the vector.</typeparam>
+        /// <typeparam name="T">The type of the elements in the vector.</typeparam>
+        /// <param name="vector">The vector to be copied.</param>
+        /// <param name="destination">The span to which the <paramref name="vector" /> is copied.</param>
+        /// <exception cref="ArgumentException">The length of <paramref name="destination" /> is less than <see cref="ISimdVector{TVector, T}.Count" />.</exception>
+        /// <exception cref="NotSupportedException">The type of the elements in the vector (<typeparamref name="T" />) is not supported.</exception>
+        public static void CopyTo<TVector, T>(this TVector vector, Span<T> destination)
+            where TVector : unmanaged, ISimdVector<TVector, T>
+            where T : struct
+        {
+            TVector.CopyTo(vector, destination);
+        }
+
+        /// <summary>Stores a vector at the given destination.</summary>
+        /// <typeparam name="TVector">The type of the vector.</typeparam>
+        /// <typeparam name="T">The type of the elements in the vector.</typeparam>
+        /// <param name="vector">The vector that will be stored.</param>
+        /// <param name="destination">The destination at which the vector will be stored.</param>
+        /// <exception cref="NotSupportedException">The type of the elements in the vector (<typeparamref name="T" />) is not supported.</exception>
+        public static void StoreUnsafe<TVector, T>(this TVector vector, ref T destination)
+            where TVector : unmanaged, ISimdVector<TVector, T>
+            where T : struct
+        {
+            TVector.StoreUnsafe(vector, ref destination);
+        }
+
+        /// <summary>Stores a vector at the given destination.</summary>
+        /// <typeparam name="TVector">The type of the vector.</typeparam>
+        /// <typeparam name="T">The type of the elements in the vector.</typeparam>
+        /// <param name="vector">The vector that will be stored.</param>
+        /// <param name="destination">The destination to which <paramref name="elementOffset" /> will be added before the vector will be stored.</param>
+        /// <param name="elementOffset">The element offset from <paramref name="destination" /> from which the vector will be stored.</param>
+        /// <exception cref="NotSupportedException">The type of the elements in the vector (<typeparamref name="T" />) is not supported.</exception>
+        public static void StoreUnsafe<TVector, T>(this TVector vector, ref T destination, nuint elementOffset)
+            where TVector : unmanaged, ISimdVector<TVector, T>
+            where T : struct
+        {
+            TVector.StoreUnsafe(vector, ref destination, elementOffset);
+        }
+
+        /// <summary>Converts the given vector to a scalar containing the value of the first element.</summary>
+        /// <typeparam name="TVector">The type of the vector.</typeparam>
+        /// <typeparam name="T">The type of the elements in the vector.</typeparam>
+        /// <param name="vector">The vector to get the first element from.</param>
+        /// <returns>A scalar <typeparamref name="T" /> containing the value of the first element.</returns>
+        /// <exception cref="NotSupportedException">The type of the elements in the vector (<typeparamref name="T" />) is not supported.</exception>
+        public static T ToScalar<TVector, T>(this TVector vector)
+            where TVector : unmanaged, ISimdVector<TVector, T>
+            where T : struct
+        {
+            return TVector.ToScalar(vector);
+        }
+
+        /// <summary>Tries to copy a vector to a given span.</summary>
+        /// <typeparam name="TVector">The type of the vector.</typeparam>
+        /// <typeparam name="T">The type of the elements in the vector.</typeparam>
+        /// <param name="vector">The vector to copy.</param>
+        /// <param name="destination">The span to which <paramref name="destination" /> is copied.</param>
+        /// <returns><c>true</c> if <paramref name="vector" /> was successfully copied to <paramref name="destination" />; otherwise, <c>false</c> if the length of <paramref name="destination" /> is less than <see cref="ISimdVector{TVector, T}.Count" />.</returns>
+        /// <exception cref="NotSupportedException">The type of the elements in the vector (<typeparamref name="T" />) is not supported.</exception>
+        public static bool TryCopyTo<TVector, T>(this TVector vector, Span<T> destination)
+            where TVector : unmanaged, ISimdVector<TVector, T>
+            where T : struct
+        {
+            return TVector.TryCopyTo(vector, destination);
+        }
+
+        /// <summary>Creates a new <see cref="Vector128{T}" /> with the element at the specified index set to the specified value and the remaining elements set to the same value as that in the given vector.</summary>
+        /// <param name="vector">The vector to get the remaining elements from.</param>
+        /// <param name="index">The index of the element to set.</param>
+        /// <param name="value">The value to set the element to.</param>
+        /// <returns>A <see cref="Vector128{T}" /> with the value of the element at <paramref name="index" /> set to <paramref name="value" /> and the remaining elements set to the same value as that in <paramref name="vector" />.</returns>
+        /// <exception cref="ArgumentOutOfRangeException"><paramref name="index" /> was less than zero or greater than the number of elements.</exception>
+        /// <exception cref="NotSupportedException">The type of the elements in the vector (<typeparamref name="T" />) is not supported.</exception>
+        public static TVector WithElement<TVector, T>(this TVector vector, int index, T value)
+            where TVector : unmanaged, ISimdVector<TVector, T>
+            where T : struct
+        {
+            return TVector.WithElement(vector, index, value);
+        }
+    }
+}