From ff742780ae5eca1cb5a62b6028da4b71505f316a Mon Sep 17 00:00:00 2001
From: Katelyn Gadd <kg@luminance.org>
Date: Thu, 25 May 2023 18:21:22 -0700
Subject: [PATCH 1/2] Attempt to optimize the Vector4 element constructor in
 mono interp

---
 .../src/System/Numerics/Vector4.cs              | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Numerics/Vector4.cs b/src/libraries/System.Private.CoreLib/src/System/Numerics/Vector4.cs
index 831b4f50d2556f..995692c8c49f8d 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Numerics/Vector4.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Numerics/Vector4.cs
@@ -15,6 +15,7 @@ namespace System.Numerics
     /// [!INCLUDE[vectors-are-rows-paragraph](~/includes/system-numerics-vectors-are-rows.md)]
     /// ]]></format></remarks>
     [Intrinsic]
+    [StructLayout(LayoutKind.Sequential)]
     public partial struct Vector4 : IEquatable<Vector4>, IFormattable
     {
         /// <summary>The X component of the vector.</summary>
@@ -63,10 +64,18 @@ public Vector4(Vector3 value, float w) : this(value.X, value.Y, value.Z, w)
         [Intrinsic]
         public Vector4(float x, float y, float z, float w)
         {
-            X = x;
-            Y = y;
-            Z = z;
-            W = w;
+            if (Vector128.IsHardwareAccelerated)
+            {
+                Unsafe.SkipInit(out this);
+                Unsafe.As<float, Vector128<float>>(ref this.X) = Vector128.Create(x, y, z, w);
+            }
+            else
+            {
+                X = x;
+                Y = y;
+                Z = z;
+                W = w;
+            }
         }
 
         /// <summary>Constructs a vector from the given <see cref="ReadOnlySpan{Single}" />. The span must contain at least 4 elements.</summary>

From 999477cdf4d8359ffcea87fb2378d673f9e1a062 Mon Sep 17 00:00:00 2001
From: Katelyn Gadd <kg@luminance.org>
Date: Thu, 25 May 2023 18:48:22 -0700
Subject: [PATCH 2/2] TIL: 'ref this' is legal in structs now

---
 .../System.Private.CoreLib/src/System/Numerics/Vector4.cs      | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Numerics/Vector4.cs b/src/libraries/System.Private.CoreLib/src/System/Numerics/Vector4.cs
index 995692c8c49f8d..fde8bb3182de6e 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Numerics/Vector4.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Numerics/Vector4.cs
@@ -15,7 +15,6 @@ namespace System.Numerics
     /// [!INCLUDE[vectors-are-rows-paragraph](~/includes/system-numerics-vectors-are-rows.md)]
     /// ]]></format></remarks>
     [Intrinsic]
-    [StructLayout(LayoutKind.Sequential)]
     public partial struct Vector4 : IEquatable<Vector4>, IFormattable
     {
         /// <summary>The X component of the vector.</summary>
@@ -67,7 +66,7 @@ public Vector4(float x, float y, float z, float w)
             if (Vector128.IsHardwareAccelerated)
             {
                 Unsafe.SkipInit(out this);
-                Unsafe.As<float, Vector128<float>>(ref this.X) = Vector128.Create(x, y, z, w);
+                Unsafe.As<Vector4, Vector128<float>>(ref this) = Vector128.Create(x, y, z, w);
             }
             else
             {