From d76d97ffc9ba23e6eec30536c6f07756e08151f2 Mon Sep 17 00:00:00 2001
From: Ben Adams <thundercat@illyriad.co.uk>
Date: Mon, 19 Nov 2018 06:18:57 +0000
Subject: [PATCH] Single pass Vectorize Span<byte>.IndexOfAny(...,
 ReadOnlySpan<byte>) for 2,3 lengths (#20738)

---
 .../shared/System/MemoryExtensions.cs         | 64 ++++++++++++++++---
 1 file changed, 54 insertions(+), 10 deletions(-)

diff --git a/src/System.Private.CoreLib/shared/System/MemoryExtensions.cs b/src/System.Private.CoreLib/shared/System/MemoryExtensions.cs
index 6145801faf..b146d2b14f 100644
--- a/src/System.Private.CoreLib/shared/System/MemoryExtensions.cs
+++ b/src/System.Private.CoreLib/shared/System/MemoryExtensions.cs
@@ -537,11 +537,32 @@ namespace System
         {
             if (typeof(T) == typeof(byte))
             {
-                return SpanHelpers.IndexOfAny(
-                    ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(span)),
-                    span.Length,
-                    ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(values)),
-                    values.Length);
+                ref byte valueRef = ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(values));
+                if (values.Length == 2)
+                {
+                    return SpanHelpers.IndexOfAny(
+                        ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(span)),
+                        valueRef,
+                        Unsafe.Add(ref valueRef, 1),
+                        span.Length);
+                }
+                else if (values.Length == 3)
+                {
+                    return SpanHelpers.IndexOfAny(
+                        ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(span)),
+                        valueRef,
+                        Unsafe.Add(ref valueRef, 1),
+                        Unsafe.Add(ref valueRef, 2),
+                        span.Length);
+                }
+                else
+                {
+                    return SpanHelpers.IndexOfAny(
+                        ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(span)),
+                        span.Length,
+                        ref valueRef,
+                        values.Length);
+                }
             }
             if (typeof(T) == typeof(char))
             {
@@ -666,11 +687,34 @@ namespace System
             where T : IEquatable<T>
         {
             if (typeof(T) == typeof(byte))
-                return SpanHelpers.IndexOfAny(
-                    ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(span)),
-                    span.Length,
-                    ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(values)),
-                    values.Length);
+            {
+                ref byte valueRef = ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(values));
+                if (values.Length == 2)
+                {
+                    return SpanHelpers.IndexOfAny(
+                        ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(span)),
+                        valueRef,
+                        Unsafe.Add(ref valueRef, 1),
+                        span.Length);
+                }
+                else if (values.Length == 3)
+                {
+                    return SpanHelpers.IndexOfAny(
+                        ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(span)),
+                        valueRef,
+                        Unsafe.Add(ref valueRef, 1),
+                        Unsafe.Add(ref valueRef, 2),
+                        span.Length);
+                }
+                else
+                {
+                    return SpanHelpers.IndexOfAny(
+                        ref Unsafe.As<T, byte>(ref MemoryMarshal.GetReference(span)),
+                        span.Length,
+                        ref valueRef,
+                        values.Length);
+                }
+            }
 
             if (typeof(T) == typeof(char))
             {
-- 
2.34.1