Assertion failed 'vnWx != NoVN' during 'Redundant branch opts'

[jakobbotsch]

// Generated by Fuzzlyn v1.5 on 2022-07-24 16:52:25
// Run on X86 Windows
// Seed: 11775672037815743472
// Reduced from 302.0 KiB to 1.4 KiB in 00:06:35
// Hits JIT assert in Release:
// Assertion failed 'vnWx != NoVN' in 'Program:M71()' during 'Redundant branch opts' (IL size 136; hash 0x996ec7e1; FullOpts)
// 
//     File: D:\a\_work\1\s\src\coreclr\jit\valuenum.cpp Line: 1306
// 
public struct S0
{
    public short F0;
    public sbyte F1;
    public S0(short f0, sbyte f1): this()
    {
        F0 = f0;
        F1 = f1;
    }
}

public struct S1
{
    public ushort F0;
    public uint F2;
    public S0 F3;
    public S0 F4;
    public int F5;
    public S1(ushort f0, uint f2, S0 f3, S0 f4, int f5): this()
    {
        F0 = f0;
        F2 = f2;
        F4 = f4;
        F5 = f5;
    }
}

public class Program
{
    public static bool[] s_7;
    public static sbyte s_26;
    public static S0[] s_44;
    public static void Main()
    {
        M71();
    }

    public static void M71()
    {
        var vr5 = (0 != s_26) || s_7[0];
        S1 vr20 = default(S1);
        for (int var15 = 0; var15 < 1; var15++)
        {
            return;
        }

        var vr7 = new S0(0, 0);
        if (!M81(true))
        {
            for (int var16 = 0; var16 < 0; var16++)
            {
                try
                {
                    System.Console.WriteLine(vr20.F3.F0);
                }
                finally
                {
                    var vr2 = new S1(0, 0, new S0(0, 0), new S0(0, 0), 0);
                }
            }
        }

        if (s_7[0])
        {
            s_44 = s_44;
        }
    }

    public static bool M81(bool arg0)
    {
        return arg0;
    }
}

Looks like another "unreachable code" example so will put it in 8.0 milestone.

cc @dotnet/jit-contrib

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Issue Details

---

// Generated by Fuzzlyn v1.5 on 2022-07-24 16:52:25
// Run on X86 Windows
// Seed: 11775672037815743472
// Reduced from 302.0 KiB to 1.4 KiB in 00:06:35
// Hits JIT assert in Release:
// Assertion failed 'vnWx != NoVN' in 'Program:M71()' during 'Redundant branch opts' (IL size 136; hash 0x996ec7e1; FullOpts)
// 
//     File: D:\a\_work\1\s\src\coreclr\jit\valuenum.cpp Line: 1306
// 
public struct S0
{
    public short F0;
    public sbyte F1;
    public S0(short f0, sbyte f1): this()
    {
        F0 = f0;
        F1 = f1;
    }
}

public struct S1
{
    public ushort F0;
    public uint F2;
    public S0 F3;
    public S0 F4;
    public int F5;
    public S1(ushort f0, uint f2, S0 f3, S0 f4, int f5): this()
    {
        F0 = f0;
        F2 = f2;
        F4 = f4;
        F5 = f5;
    }
}

public class Program
{
    public static bool[] s_7;
    public static sbyte s_26;
    public static S0[] s_44;
    public static void Main()
    {
        M71();
    }

    public static void M71()
    {
        var vr5 = (0 != s_26) || s_7[0];
        S1 vr20 = default(S1);
        for (int var15 = 0; var15 < 1; var15++)
        {
            return;
        }

        var vr7 = new S0(0, 0);
        if (!M81(true))
        {
            for (int var16 = 0; var16 < 0; var16++)
            {
                try
                {
                    System.Console.WriteLine(vr20.F3.F0);
                }
                finally
                {
                    var vr2 = new S1(0, 0, new S0(0, 0), new S0(0, 0), 0);
                }
            }
        }

        if (s_7[0])
        {
            s_44 = s_44;
        }
    }

    public static bool M81(bool arg0)
    {
        return arg0;
    }
}

Looks like another "unreachable code" example so will put it in 8.0 milestone.

cc @dotnet/jit-contrib

Author:	jakobbotsch
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	-

[AndyAyersMS]

Seems like an issue introduced when we added fgGetDomSpeculatively in #70907. I think I can tweak that method not to be as easily fooled by unreachable code.