JIT: Bad codegen with Vector256 shift by Vector128

[jakobbotsch]

// Generated by Fuzzlyn v1.7 on 2024-07-25 11:06:17
// Run on X64 Windows
// Seed: 1535747306914661768-vectort,vector128,vector256,x86aes,x86avx,x86avx2,x86bmi1,x86bmi1x64,x86bmi2,x86bmi2x64,x86fma,x86lzcnt,x86lzcntx64,x86pclmulqdq,x86popcnt,x86popcntx64,x86sse,x86ssex64,x86sse2,x86sse2x64,x86sse3,x86sse41,x86sse41x64,x86sse42,x86sse42x64,x86ssse3,x86x86base
// Reduced from 95.3 KiB to 0.6 KiB in 00:00:29
// Debug: Outputs <0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0>
// Release: Outputs <0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1>
using System;
using System.Runtime.CompilerServices;
using System.Numerics;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;

public class Program
{
    public static IRuntime s_rt;
    public static void Main()
    {
        s_rt = new Runtime();
        var vr2 = Vector256.Create<ushort>(1);
        var vr3 = Vector128.Create<ushort>(1);
        Vector256<ushort> vr4 = Avx2.ShiftLeftLogical(vr2, vr3);
        s_rt.WriteLine(vr4);
    }
}

public interface IRuntime
{
    void WriteLine<T>(T value);
}

public class Runtime : IRuntime
{
    public void WriteLine<T>(T value) => System.Console.WriteLine(value);
}

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[jakobbotsch]

Similar example:

// Generated by Fuzzlyn v1.7 on 2024-07-25 11:23:13
// Run on X64 Windows
// Seed: 13541437200857789110-vectort,vector128,vector256,x86aes,x86avx,x86avx2,x86bmi1,x86bmi1x64,x86bmi2,x86bmi2x64,x86fma,x86lzcnt,x86lzcntx64,x86pclmulqdq,x86popcnt,x86popcntx64,x86sse,x86ssex64,x86sse2,x86sse2x64,x86sse3,x86sse41,x86sse41x64,x86sse42,x86sse42x64,x86ssse3,x86x86base
// Reduced from 81.2 KiB to 0.8 KiB in 00:00:28
// Debug: Outputs <0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0>
// Release: Outputs <0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1>
using System;
using System.Runtime.CompilerServices;
using System.Numerics;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;

public class Program
{
    public static IRuntime s_rt;
    public static void Main()
    {
        s_rt = new Runtime();
        var vr10 = (short)0;
        var vr11 = Vector256.CreateScalar(vr10);
        var vr12 = Vector256.Create<short>(1);
        var vr13 = Avx2.Xor(vr11, vr12);
        var vr14 = (short)1;
        var vr15 = Vector128.CreateScalar(vr14);
        var vr16 = Avx2.ShiftRightArithmetic(vr13, vr15);
        s_rt.WriteLine(vr16);
    }
}

public interface IRuntime
{
    void WriteLine<T>(T value);
}

public class Runtime : IRuntime
{
    public void WriteLine<T>(T value) => System.Console.WriteLine(value);
}