CoreFX dotnet#24343 Vector using Span

dotnet/corefx#24343

Author: WinCPP

src/mscorlib/Resources/Strings.resx

@@ -3718,4 +3718,7 @@
   <data name="Argument_OverlapAlignmentMismatch" xml:space="preserve">
     <value>Overlapping spans have mismatching alignment.</value>
   </data>
+  <data name="Arg_InsufficientNumberOfElements" xml:space="preserve">
+    <value>At least {0} element(s) are expected in the parameter "{1}".</value>
+  </data>
 </root>

src/mscorlib/shared/System/Numerics/GenerationConfig.ttinclude

@@ -1,5 +1,6 @@
 <#@ import namespace="System.Linq" #>
 <#@ import namespace="System.Collections.Generic" #>
+<#@ import namespace="System.Text" #>
 <#+ 
     /*    This file includes static data used as compilation configuration for the rest of the code generation. 
         It is shared here to ensure that all generated code compiles with the same constants and configurations.    */
@@ -144,4 +145,28 @@
         string keyword = (type == allTypes.ToArray()[0]) ? "if" : "else if";
         return string.Format("{0} (typeof(T) == typeof({1}))", keyword, type.Name);
     }
-#>
+
+    public string MakeTypeComparisonCondition(Type type)
+    {
+        return string.Format("(typeof(T) == typeof({0}))", type.Name);
+    }
+
+    public string GenerateIfConditionAllTypes(IEnumerable<Type> allTypes)
+    {
+        StringBuilder sbuilder = new StringBuilder();
+        var arrAllTypes = allTypes.ToArray();
+        for (int index = 0; index < arrAllTypes.Length; ++index)
+        {
+            if (index == 0)
+            {
+                sbuilder.Append("if (").Append(MakeTypeComparisonCondition(arrAllTypes[index]));
+            }
+            else
+            {
+                sbuilder.AppendLine().Append("                || ").Append(MakeTypeComparisonCondition(arrAllTypes[index]));
+            }
+        }
+        sbuilder.Append(")");
+        return sbuilder.ToString();
+    }
+#>

src/mscorlib/shared/System/Numerics/Vector.cs

@@ -2,9 +2,13 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#if !netstandard
+using Internal.Runtime.CompilerServices;
+#endif
 using System.Globalization;
 using System.Numerics.Hashing;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using System.Text;
 
 namespace System.Numerics
@@ -763,6 +767,36 @@ private Vector(ref Register existingRegister)
         {
             this.register = existingRegister;
         }
+
+        /// <summary>
+        /// Constructs a vector from the given span. The span must contain at least Vector'T.Count elements.
+        /// </summary>
+        [Intrinsic]
+        public unsafe Vector(Span<T> values)
+            : this()
+        {
+            if ((typeof(T) == typeof(Byte))
+                || (typeof(T) == typeof(SByte))
+                || (typeof(T) == typeof(UInt16))
+                || (typeof(T) == typeof(Int16))
+                || (typeof(T) == typeof(UInt32))
+                || (typeof(T) == typeof(Int32))
+                || (typeof(T) == typeof(UInt64))
+                || (typeof(T) == typeof(Int64))
+                || (typeof(T) == typeof(Single))
+                || (typeof(T) == typeof(Double)))
+            {
+                if (values.Length < Count)
+                {
+                    throw new IndexOutOfRangeException(SR.Format(SR.Arg_InsufficientNumberOfElements, Vector<T>.Count, nameof(values)));
+                }
+                this = Unsafe.ReadUnaligned<Vector<T>>(ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(values)));
+            }
+            else
+            {
+                throw new NotSupportedException(SR.Arg_TypeNotSupported);
+            }
+        }
         #endregion Constructors
 
         #region Public Instance Methods

src/mscorlib/shared/System/Numerics/Vector.tt

@@ -7,9 +7,13 @@
 <#@ import namespace="System.Runtime.InteropServices" #>
 <#@ include file="GenerationConfig.ttinclude" #><# GenerateCopyrightHeader(); #>
 
+#if !netstandard
+using Internal.Runtime.CompilerServices;
+#endif
 using System.Globalization;
 using System.Numerics.Hashing;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using System.Text;
 
 namespace System.Numerics
@@ -283,6 +287,27 @@ namespace System.Numerics
         {
             this.register = existingRegister;
         }
+
+        /// <summary>
+        /// Constructs a vector from the given span. The span must contain at least Vector'T.Count elements.
+        /// </summary>
+        [Intrinsic]
+        public unsafe Vector(Span<T> values)
+            : this()
+        {
+            <#=GenerateIfConditionAllTypes(supportedTypes)#>
+            {
+                if (values.Length < Count)
+                {
+                    throw new IndexOutOfRangeException(SR.Format(SR.Arg_InsufficientNumberOfElements, Vector<T>.Count, nameof(values)));
+                }
+                this = Unsafe.ReadUnaligned<Vector<T>>(ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(values)));
+            }
+            else
+            {
+                throw new NotSupportedException(SR.Arg_TypeNotSupported);
+            }
+        }
         #endregion Constructors
 
         #region Public Instance Methods