optimization: removed temporal buffer creation from ToVector4SimdAligned()

src/ImageSharp/Common/Memory/BufferSpan.cs

@@ -6,6 +6,7 @@
 namespace ImageSharp
 {
     using System;
+    using System.Numerics;
     using System.Runtime.CompilerServices;
     using System.Runtime.InteropServices;
 
@@ -14,6 +15,19 @@ namespace ImageSharp
     /// </summary>
     internal static class BufferSpan
     {
+        /// <summary>
+        /// Fetches a <see cref="Vector{T}"/> from the beginning of the span.
+        /// </summary>
+        /// <typeparam name="T">The value type</typeparam>
+        /// <param name="span">The span to fetch the vector from</param>
+        /// <returns>A <see cref="Vector{T}"/> reference to the beginning of the span</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static ref Vector<T> FetchVector<T>(this BufferSpan<T> span)
+            where T : struct
+        {
+            return ref Unsafe.As<T, Vector<T>>(ref span.DangerousGetPinnableReference());
+        }
+
         /// <summary>
         /// Copy 'count' number of elements of the same type from 'source' to 'dest'
         /// </summary>

src/ImageSharp/PixelFormats/Rgba32.PixelOperations.cs

@@ -61,38 +61,33 @@ namespace ImageSharp
 
                 int unpackedRawCount = count * 4;
 
-                ref uint src = ref Unsafe.As<Rgba32, uint>(ref sourceColors.DangerousGetPinnableReference());
+                ref uint bSource = ref Unsafe.As<Rgba32, uint>(ref sourceColors.DangerousGetPinnableReference());
+                ref UnpackedRGBA bDestUnpacked = ref Unsafe.As<Vector4, UnpackedRGBA>(ref destVectors.DangerousGetPinnableReference());
+                ref Vector<uint> bDestUint = ref Unsafe.As<UnpackedRGBA, Vector<uint>>(ref bDestUnpacked);
+                ref Vector<float> bDestFloat = ref Unsafe.As<UnpackedRGBA, Vector<float>>(ref bDestUnpacked);
 
-                using (Buffer<uint> tempBuf = new Buffer<uint>(
-                    unpackedRawCount + Vector<uint>.Count))
+                for (int i = 0; i < count; i++)
                 {
-                    uint[] temp = tempBuf.Array;
-                    float[] fTemp = Unsafe.As<float[]>(temp);
-
-                    ref UnpackedRGBA tempBase = ref Unsafe.As<uint, UnpackedRGBA>(ref tempBuf[0]);
+                    uint sVal = Unsafe.Add(ref bSource, i);
+                    ref UnpackedRGBA dst = ref Unsafe.Add(ref bDestUnpacked, i);
 
-                    for (int i = 0; i < count; i++)
-                    {
-                        uint sVal = Unsafe.Add(ref src, i);
-                        ref UnpackedRGBA dst = ref Unsafe.Add(ref tempBase, i);
+                    // This call is the bottleneck now:
+                    dst.Load(sVal);
+                }
 
-                        // This call is the bottleneck now:
-                        dst.Load(sVal);
-                    }
+                int n = unpackedRawCount / vecSize;
 
-                    for (int i = 0; i < unpackedRawCount; i += vecSize)
-                    {
-                        Vector<uint> vi = new Vector<uint>(temp, i);
+                for (int i = 0; i < n; i++)
+                {
+                    Vector<uint> vi = Unsafe.Add(ref bDestUint, i);
 
-                        vi &= mask;
-                        vi |= magicInt;
+                    vi &= mask;
+                    vi |= magicInt;
 
-                        Vector<float> vf = Vector.AsVectorSingle(vi);
-                        vf = (vf - magicFloat) * bVec;
-                        vf.CopyTo(fTemp, i);
-                    }
+                    Vector<float> vf = Vector.AsVectorSingle(vi);
+                    vf = (vf - magicFloat) * bVec;
 
-                    BufferSpan.Copy(tempBuf.Span.AsBytes(), destVectors.AsBytes(), unpackedRawCount * sizeof(uint));
+                    Unsafe.Add(ref bDestFloat, i) = vf;
                 }
             }
 

tests/ImageSharp.Benchmarks/Color/Bulk/PackFromXyzw.cs

@@ -57,7 +57,7 @@ namespace ImageSharp.Benchmarks.Color.Bulk
         }
     }
 
-    public class PackFromXyzw_Color : PackFromXyzw<Rgba32>
+    public class PackFromXyzw_Rgba32 : PackFromXyzw<Rgba32>
     {
     }
 }

tests/ImageSharp.Benchmarks/Color/Bulk/ToVector4.cs

@@ -57,7 +57,7 @@ namespace ImageSharp.Benchmarks.Color.Bulk
         }
     }
 
-    public class ToVector4_Color : ToVector4<Rgba32>
+    public class ToVector4_Rgba32 : ToVector4<Rgba32>
     {
     }
 }

tests/ImageSharp.Benchmarks/Color/Bulk/ToXyz.cs

@@ -55,7 +55,7 @@ namespace ImageSharp.Benchmarks.Color.Bulk
         }
     }
 
-    public class ToXyz_Color : ToXyz<Rgba32>
+    public class ToXyz_Rgba32 : ToXyz<Rgba32>
     {
     }
 }

tests/ImageSharp.Benchmarks/Color/Bulk/ToXyzw.cs

@@ -59,11 +59,11 @@ namespace ImageSharp.Benchmarks.Color.Bulk
         }
     }
     
-    public class ToXyzw_Color : ToXyzw<Rgba32>
+    public class ToXyzw_Rgba32 : ToXyzw<Rgba32>
     {
     }
 
-    public class ToXyzw_Argb : ToXyzw<Argb32>
+    public class ToXyzw_Argb32 : ToXyzw<Argb32>
     {
     }
 }

tests/ImageSharp.Benchmarks/General/Vectorization/VectorFetching.cs

@@ -86,5 +86,23 @@ namespace ImageSharp.Benchmarks.General.Vectorization
                 a = a * v;
             }
         }
+
+        [Benchmark]
+        public void FetchWithBufferSpanUtility()
+        {
+            Vector<float> v = new Vector<float>(this.testValue);
+
+            BufferSpan<float> span = new BufferSpan<float>(this.data);
+
+            ref Vector<float> start = ref span.FetchVector();
+
+            int n = this.InputSize / Vector<uint>.Count;
+
+            for (int i = 0; i < n; i++)
+            {
+                ref Vector<float> a = ref Unsafe.Add(ref start, i);
+                a = a * v;
+            }
+        }
     }
 }

tests/ImageSharp.Tests/Colors/PixelOperationsTests.cs

@@ -12,7 +12,7 @@ namespace ImageSharp.Tests.Colors
 
     public class PixelOperationsTests
     {
-        public class Color32 : BulkPixelOperationsTests<Rgba32>
+        public class Color32 : PixelOperationsTests<Rgba32>
         {
             public Color32(ITestOutputHelper output)
                 : base(output)
@@ -20,7 +20,7 @@ namespace ImageSharp.Tests.Colors
             }
 
             // For 4.6 test runner MemberData does not work without redeclaring the public field in the derived test class:
-            //public static new TheoryData<int> ArraySizesData => new TheoryData<int> { 7, 16, 1111 };
+            public static new TheoryData<int> ArraySizesData => new TheoryData<int> { 7, 16, 1111 };
 
             [Fact]
             public void IsSpecialImplementation()
@@ -60,7 +60,7 @@ namespace ImageSharp.Tests.Colors
             }
         }
 
-        public class Argb : BulkPixelOperationsTests<Argb32>
+        public class Argb : PixelOperationsTests<Argb32>
         {
             // For 4.6 test runner MemberData does not work without redeclaring the public field in the derived test class:
             public Argb(ITestOutputHelper output)
@@ -68,7 +68,7 @@ namespace ImageSharp.Tests.Colors
             {
             }
 
-            //public static new TheoryData<int> ArraySizesData => new TheoryData<int> { 7, 16, 1111 };
+            public static new TheoryData<int> ArraySizesData => new TheoryData<int> { 7, 16, 1111 };
         }
 
         [Theory]
@@ -80,10 +80,10 @@ namespace ImageSharp.Tests.Colors
         }
     }
 
-    public abstract class BulkPixelOperationsTests<TPixel> : MeasureFixture
+    public abstract class PixelOperationsTests<TPixel> : MeasureFixture
         where TPixel : struct, IPixel<TPixel>
     {
-        protected BulkPixelOperationsTests(ITestOutputHelper output)
+        protected PixelOperationsTests(ITestOutputHelper output)
             : base(output)
         {
         }

tests/ImageSharp.Tests/Common/BufferSpanTests.cs

@@ -4,6 +4,7 @@
 namespace ImageSharp.Tests.Common
 {
     using System;
+    using System.Numerics;
     using System.Runtime.CompilerServices;
 
     using ImageSharp.PixelFormats;
@@ -25,6 +26,21 @@ namespace ImageSharp.Tests.Common
             }
         }
 
+        [Fact]
+        public void FetchVector()
+        {
+            float[] stuff = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
+
+            BufferSpan<float> span = new BufferSpan<float>(stuff);
+
+            ref Vector<float> v = ref span.FetchVector();
+
+            Assert.Equal(0, v[0]);
+            Assert.Equal(1, v[1]);
+            Assert.Equal(2, v[2]);
+            Assert.Equal(3, v[3]);
+        }
+
         [Fact]
         public void AsBytes()
         {