Odin vs C#

CSharpBench.cs

using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.Intrinsics;

namespace CSharpLib;

public class CSharpBench
{
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static int[] CSharp_Bench2(int[] a, int[] b, int[] result, int size)
    {
        int vectorSize = Vector256<int>.Count;

        var spanA = a.AsSpan();
        var spanB = b.AsSpan();
        var spanResult = MemoryMarshal.Cast<int, Vector256<int>>(result);
        
        var vectorsA = MemoryMarshal.Cast<int, Vector256<int>>(spanA);
        var vectorsB = MemoryMarshal.Cast<int, Vector256<int>>(spanB);

        for (var i = 0; i < vectorsA.Length; i++)
        {
            var va = vectorsA[i];
            var vb = vectorsB[i];

            var mask = Vector256.LessThan(va, vb);
            var vsum = Vector256.Add(va, Vector256.Multiply(vb, va));
            var vdiff = Vector256.Subtract(Vector256.Multiply(va, vb), vb);

            var vresult = Vector256.ConditionalSelect(mask, vsum, vdiff);

            spanResult[i] = vresult;
        }

        var remaining = size - spanA.Length * vectorSize;
        for (int i = size - remaining; i < size; i++)
        {
            if (a[i] < b[i])
            {
                result[i] = a[i] + b[i];
            }
            else
            {
                result[i] = a[i] - b[i];
            }
        }

        return result;
    }
}

References:

• Introduction to vectorization with Vector128 and Vector256
• Single Instruction, Multiple Data (SIMD) in .NET