Merge pull request #31 from rameel/advsimd-support

rameel · web-flow · commit 3759e5ae5fbb · 2025-07-14T17:33:03.000+05:00
Add AdvSimd support
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, windows-latest]
+        os: [ubuntu-latest, ubuntu-24.04-arm, windows-latest]
 
     steps:
       - name: Setup .NET
@@ -38,24 +38,22 @@ jobs:
       - name: Test (Release)
         run: dotnet test -c Release --no-build
 
-      - name: Test (Debug, Avx2=Disabled)
+      - name: Test (Debug, AVX2=0)
         env:
-          COMPlus_EnableAVX2: "0"
+          DOTNET_EnableAVX2: "0"
         run: dotnet test -c Debug --no-build
 
-      - name: Test (Release, Avx2=Disabled)
+      - name: Test (Release, AVX2=0)
         env:
-          COMPlus_EnableAVX2: "0"
+          DOTNET_EnableAVX2: "0"
         run: dotnet test -c Release --no-build
 
-      - name: Test (Debug, Avx2=Disabled, Sse2=Disabled)
+      - name: Test (Debug, HWIntrinsic=0)
         env:
-          COMPlus_EnableAVX2: "0"
-          COMPlus_EnableSSE2: "0"
+          DOTNET_EnableHWIntrinsic: "0"
         run: dotnet test -c Debug --no-build
 
-      - name: Test (Release, Avx2=Disabled, Sse2=Disabled)
+      - name: Test (Release, HWIntrinsic=0)
         env:
-          COMPlus_EnableAVX2: "0"
-          COMPlus_EnableSSE2: "0"
+          DOTNET_EnableHWIntrinsic: "0"
         run: dotnet test -c Release --no-build
diff --git a/Ramstack.Globbing.Tests/Ramstack.Globbing.Tests.csproj b/Ramstack.Globbing.Tests/Ramstack.Globbing.Tests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <LangVersion>preview</LangVersion>
diff --git a/Ramstack.Globbing.Tests/SimdConfigurationTests.cs b/Ramstack.Globbing.Tests/SimdConfigurationTests.cs
@@ -1,3 +1,5 @@
+using System.Runtime.InteropServices;
+using System.Runtime.Intrinsics.Arm;
 using System.Runtime.Intrinsics.X86;
 
 namespace Ramstack.Globbing;
@@ -8,10 +10,19 @@ public class SimdConfigurationTests
     [Test]
     public void VerifySimdConfiguration()
     {
-        var isAvx2Disabled = Environment.GetEnvironmentVariable("COMPlus_EnableAVX2") == "0";
-        var isSse2Disabled = Environment.GetEnvironmentVariable("COMPlus_EnableSSE2") == "0";
+        if (Environment.GetEnvironmentVariable("DOTNET_EnableHWIntrinsic") == "0")
+        {
+            Assert.That(Sse2.IsSupported, Is.False);
+            Assert.That(Sse41.IsSupported, Is.False);
+            Assert.That(Avx2.IsSupported, Is.False);
+            Assert.That(AdvSimd.IsSupported, Is.False);
+        }
 
-        Assert.That(isAvx2Disabled, Is.EqualTo(!Avx2.IsSupported));
-        Assert.That(isSse2Disabled, Is.EqualTo(!Sse2.IsSupported));
+        if (RuntimeInformation.ProcessArchitecture == Architecture.X64 && Environment.GetEnvironmentVariable("DOTNET_EnableAVX2") == "0")
+        {
+            Assert.That(Sse2.IsSupported, Is.True);
+            Assert.That(Sse41.IsSupported, Is.True);
+            Assert.That(Avx2.IsSupported, Is.False);
+        }
     }
 }
diff --git a/Ramstack.Globbing/Internal/PathHelper.cs b/Ramstack.Globbing/Internal/PathHelper.cs
@@ -4,6 +4,7 @@
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Runtime.Intrinsics;
+using System.Runtime.Intrinsics.Arm;
 using System.Runtime.Intrinsics.X86;
 
 namespace Ramstack.Globbing.Internal;
@@ -172,14 +173,46 @@ static void ConvertPathToPosixStyleImpl(ref char p, nint length)
                 }
                 while (i < tail);
 
+                //
                 // Process remaining chars
                 // NOTE: An extra one write for the 'length == Vector128<ushort>.Count'
+                //
 
                 value = LoadVector128(ref p, tail);
                 mask = Sse2.CompareEqual(value, backslash);
                 result = Sse41.BlendVariable(value, slash, mask);
                 WriteVector128(ref p, tail, result);
             }
+            else if (AdvSimd.IsSupported && length >= Vector128<ushort>.Count)
+            {
+                Vector128<ushort> value;
+                Vector128<ushort> mask;
+                Vector128<ushort> result;
+
+                var slash = Vector128.Create((ushort)'/');
+                var backslash = Vector128.Create((ushort)'\\');
+                var tail = length - Vector128<ushort>.Count;
+
+                do
+                {
+                    value = LoadVector128(ref p, i);
+                    mask = AdvSimd.CompareEqual(value, backslash);
+                    result = AdvSimd.BitwiseSelect(mask, slash, value);
+                    WriteVector128(ref p, i, result);
+
+                    i += Vector128<ushort>.Count;
+                }
+                while (i < tail);
+
+                //
+                // Process remaining chars
+                // NOTE: An extra one write for the 'length == Vector128<ushort>.Count'
+                //
+                value = LoadVector128(ref p, tail);
+                mask = AdvSimd.CompareEqual(value, backslash);
+                result = AdvSimd.BitwiseSelect(mask, slash, value);
+                WriteVector128(ref p, tail, result);
+            }
             else
             {
                 for (; i < length; i++)
@@ -198,10 +231,10 @@ static void ConvertPathToPosixStyleImpl(ref char p, nint length)
     /// <returns>
     /// A 256-bit bitmask for escaping characters.
     /// </returns>
-    private static Vector256<ushort> CreateAllowEscaping256Bitmask(MatchFlags flags)
+    private static Vector256<ushort> CreateBackslash256Bitmask(MatchFlags flags)
     {
         var mask = Vector256<ushort>.Zero;
-        if (flags != MatchFlags.Windows)
+        if (flags == MatchFlags.Windows)
             mask = Vector256<ushort>.AllBitsSet;
 
         return mask;
@@ -214,10 +247,10 @@ private static Vector256<ushort> CreateAllowEscaping256Bitmask(MatchFlags flags)
     /// <returns>
     /// A 128-bit bitmask for escaping characters.
     /// </returns>
-    private static Vector128<ushort> CreateAllowEscaping128Bitmask(MatchFlags flags)
+    private static Vector128<ushort> CreateBackslash128Bitmask(MatchFlags flags)
     {
         var mask = Vector128<ushort>.Zero;
-        if (flags != MatchFlags.Windows)
+        if (flags == MatchFlags.Windows)
             mask = Vector128<ushort>.AllBitsSet;
 
         return mask;
@@ -301,15 +334,37 @@ public PathSegmentIterator() =>
 
             while ((int)_position < length)
             {
-                if ((Avx2.IsSupported || Sse2.IsSupported) && _mask != 0)
+                if ((Avx2.IsSupported || Sse2.IsSupported || AdvSimd.IsSupported) && _mask != 0)
                 {
                     var offset = BitOperations.TrailingZeroCount(_mask);
-                    _last = (int)(_position + (nint)((uint)offset >> 1));
+                    if (AdvSimd.IsSupported)
+                    {
+                        //
+                        // On ARM, ExtractMostSignificantBits returns a mask where each bit
+                        // represents one vector element (1 bit per ushort), so offset
+                        // directly corresponds to the element index
+                        //
+                        _last = (int)(_position + (nint)(uint)offset);
 
-                    //
-                    // Clear the bits for the current separator to process the next position in the mask
-                    //
-                    _mask &= ~(0b_11u << offset);
+                        //
+                        // Clear the bits for the current separator
+                        //
+                        _mask &= ~(1u << offset);
+                    }
+                    else
+                    {
+                        //
+                        // On x86, MoveMask (and ExtractMostSignificantBits on byte-based vectors)
+                        // returns a mask where each bit represents one byte (2 bits per ushort),
+                        // so we need to divide offset by 2 to get the actual element index
+                        //
+                        _last = (int)(_position + (nint)((uint)offset >> 1));
+
+                        //
+                        // Clear the bits for the current separator
+                        //
+                        _mask &= ~(0b_11u << offset);
+                    }
 
                     //
                     // Advance position to the next chunk when no separators remain in the mask
@@ -340,14 +395,14 @@ public PathSegmentIterator() =>
                 if (Avx2.IsSupported && (int)_position + Vector256<ushort>.Count <= length)
                 {
                     var chunk = LoadVector256(ref source, _position);
-                    var allowEscapingMask = CreateAllowEscaping256Bitmask(flags);
+                    var backslashMask = CreateBackslash256Bitmask(flags);
                     var slash = Vector256.Create((ushort)'/');
                     var backslash = Vector256.Create((ushort)'\\');
 
                     var comparison = Avx2.Or(
                         Avx2.CompareEqual(chunk, slash),
-                        Avx2.AndNot(
-                            allowEscapingMask,
+                        Avx2.And(
+                            backslashMask,
                             Avx2.CompareEqual(chunk, backslash)));
 
                     //
@@ -367,14 +422,14 @@ public PathSegmentIterator() =>
                 else if (Sse2.IsSupported && !Avx2.IsSupported && (int)_position + Vector128<ushort>.Count <= length)
                 {
                     var chunk = LoadVector128(ref source, _position);
-                    var allowEscapingMask = CreateAllowEscaping128Bitmask(flags);
+                    var backslashMask = CreateBackslash128Bitmask(flags);
                     var slash = Vector128.Create((ushort)'/');
                     var backslash = Vector128.Create((ushort)'\\');
 
                     var comparison = Sse2.Or(
                         Sse2.CompareEqual(chunk, slash),
-                        Sse2.AndNot(
-                            allowEscapingMask,
+                        Sse2.And(
+                            backslashMask,
                             Sse2.CompareEqual(chunk, backslash)));
 
                     //
@@ -391,6 +446,35 @@ public PathSegmentIterator() =>
                     if (_mask == 0)
                         _position += Vector128<ushort>.Count;
                 }
+                #if NET7_0_OR_GREATER
+                else if (AdvSimd.IsSupported && (int)_position + Vector128<ushort>.Count <= length)
+                {
+                    var chunk = LoadVector128(ref source, _position);
+                    var backslashMask = CreateBackslash128Bitmask(flags);
+                    var slash = Vector128.Create((ushort)'/');
+                    var backslash = Vector128.Create((ushort)'\\');
+
+                    var comparison = AdvSimd.Or(
+                        AdvSimd.CompareEqual(chunk, slash),
+                        AdvSimd.And(
+                            backslashMask,
+                            AdvSimd.CompareEqual(chunk, backslash)));
+
+                    //
+                    // Store the comparison bitmask and reuse it across iterations
+                    // as long as it contains non-zero bits.
+                    // This avoids reloading SIMD registers and repeating comparisons
+                    // on the same chunk of data.
+                    //
+                    _mask = comparison.ExtractMostSignificantBits();
+
+                    //
+                    // Advance position to the next chunk when no separators found
+                    //
+                    if (_mask == 0)
+                        _position += Vector128<ushort>.Count;
+                }
+                #endif
                 else
                 {
                     for (; (int)_position < length; _position++)
diff --git a/Ramstack.Globbing/Ramstack.Globbing.csproj b/Ramstack.Globbing/Ramstack.Globbing.csproj
@@ -1,6 +1,6 @@
-<Project Sdk="Microsoft.NET.Sdk">
+﻿<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
     <Description>Fast and zero-allocation .NET globbing library for matching file paths using glob patterns.</Description>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
