Vector256.Shuffle() returns incorrect result when index is out of bounds

[DeepakRajendrakumaran]

Description

Vector256.Shuffle() returns incorrect result when index is out of bounds. When index is out of bounds, expected to return 0 for that and rest of values correctly

Reproduction Steps

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

namespace InterfaceMain
{
    interface Program
    {
          public static unsafe int Main()
        {

            Vector256<int> v256Shuffle1 = Vector256.Create(100, 101, 102, 103, 104, 105, 106, 107);
            Vector256<int> resultElements256Shuffle = Vector256Shuffle(v256Shuffle1);
            Console.Write("\n Vector256Shuffle [ ");
            for (int index = 0; index < Vector256<int>.Count; index++)
            {
                Console.Write(resultElements256Shuffle[index] + ", ");
            }
            Console.Write("]\n Vector256Shuffle Done \n");




            return 100;
        }

        

        [MethodImpl(MethodImplOptions.NoInlining)]
        public static unsafe Vector256<int> Vector256Shuffle(Vector256<int> v1)
        {
            return Vector256.Shuffle(v1, Vector256.Create(7, 555, 3, 1, 6, 4, 2, 0));
        }

    }
}

Expected behavior

Not crash and return 0 for out of bound index

Actual behavior

Crashed on latest main for Debug build

on 7.0, returns incorrect value on sharplab(release?) :

Vector256Suffle [ 107, 0, 103, 101, 0, 0, 0, 0, ]
 Vector256Shuffle Done 

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

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Issue Details

---

Description

Vector256.Shuffle() returns incorrect result when index is out of bounds. When index is out of bounds, expected to return 0 for that and rest of values correctly

Reproduction Steps

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

namespace InterfaceMain
{
    interface Program
    {
          public static unsafe int Main()
        {

            Vector256<int> v256Shuffle1 = Vector256.Create(100, 101, 102, 103, 104, 105, 106, 107);
            Vector256<int> resultElements256Shuffle = Vector256Shuffle(v256Shuffle1);
            Console.Write("\n Vector256Shuffle [ ");
            for (int index = 0; index < Vector256<int>.Count; index++)
            {
                Console.Write(resultElements256Shuffle[index] + ", ");
            }
            Console.Write("]\n Vector256Shuffle Done \n");




            return 100;
        }

        

        [MethodImpl(MethodImplOptions.NoInlining)]
        public static unsafe Vector256<int> Vector256Shuffle(Vector256<int> v1)
        {
            return Vector256.Shuffle(v1, Vector256.Create(7, 555, 3, 1, 6, 4, 2, 0));
        }

    }
}

Expected behavior

Not crash and return 0 for out of bound index

Actual behavior

Crashed on latest main

on 7.0, returns incorrect value :

Vector256Suffle [ 107, 0, 103, 101, 0, 0, 0, 0, ]
 Vector256Shuffle Done 

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

Author:	DeepakRajendrakumaran
Assignees:	-
Labels:	area-System.Numerics, untriaged
Milestone:	-

[tannergooding]

This was resolved in #86453