JIT: Bad codegen on x86

[jakobbotsch]

// Generated by Fuzzlyn v1.6 on 2023-11-19 16:39:12
// Run on X86 Windows
// Seed: 8102521250723522311
// Reduced from 379.8 KiB to 2.0 KiB in 00:15:51
// Debug: Outputs 65536
// Release: Outputs 0
using System.Runtime.CompilerServices;

public interface I2
{
    ushort M47(ulong arg0);
}

public struct S0
{
    public ushort F0;
    public short F1;
    public uint F2;
    public sbyte F3;
    public S0(short f1): this()
    {
        F1 = f1;
    }
}

public struct S1 : I2
{
    public uint F0;
    public S0 F1;
    public byte F2;
    public bool F3;
    public ushort F4;
    public bool F5;
    public S0 F6;
    public S1(S0 f1): this()
    {
        F1 = f1;
    }

    public ushort M47(ulong arg0)
    {
        I2[] var5 = new I2[]{new S1(new S0(1))};
        var vr5 = new S1(new S0(0));
        var vr6 = this.F1.F2;
        var vr7 = this.F6.F0;
        var vr9 = Program.s_4;
        var vr10 = this.F1;
        var vr11 = var5[0];
        var vr12 = Program.s_34[0];
        bool vr1 = Program.M49(vr5, vr6, vr7, vr9, vr10, vr11, vr12);
        var vr13 = this;
        return (ushort)Program.M48(vr13);
    }
}

public class C0
{
    public S1 F2;
}

public class Program
{
    public static IRuntime s_rt;
    public static S1 s_4 = new S1(new S0(1));
    public static C0[] s_16 = new C0[]{new C0()};
    public static int[] s_34 = new int[]{0};
    public static void Main()
    {
        s_rt = new Runtime();
        var vr17 = new I2[]{new S1(new S0(0))};
        short vr24 = s_16[0].F2.F1.F1;
        var vr21 = (ulong)vr24;
        ushort vr22 = vr17[0].M47(vr21);
    }

    public static bool M49(S1 arg0, uint arg1, ushort arg2, S1 arg3, S0 arg4, I2 arg5, int arg6)
    {
        arg0 = arg3;
        arg0.F1 = Unsafe.ReadUnaligned<S0>(ref Unsafe.As<uint, byte>(ref arg3.F0));
        s_rt.WriteLine(arg0.F1.F2);
        return arg0.F5;
    }

    public static ref short M48(S1 argThis)
    {
        return ref s_16[0].F2.F1.F1;
    }
}

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

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

[ghost]

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
See info in area-owners.md if you want to be subscribed.

Issue Details

---

// Generated by Fuzzlyn v1.6 on 2023-11-19 16:39:12
// Run on X86 Windows
// Seed: 8102521250723522311
// Reduced from 379.8 KiB to 2.0 KiB in 00:15:51
// Debug: Outputs 65536
// Release: Outputs 0
using System.Runtime.CompilerServices;

public interface I2
{
    ushort M47(ulong arg0);
}

public struct S0
{
    public ushort F0;
    public short F1;
    public uint F2;
    public sbyte F3;
    public S0(short f1): this()
    {
        F1 = f1;
    }
}

public struct S1 : I2
{
    public uint F0;
    public S0 F1;
    public byte F2;
    public bool F3;
    public ushort F4;
    public bool F5;
    public S0 F6;
    public S1(S0 f1): this()
    {
        F1 = f1;
    }

    public ushort M47(ulong arg0)
    {
        I2[] var5 = new I2[]{new S1(new S0(1))};
        var vr5 = new S1(new S0(0));
        var vr6 = this.F1.F2;
        var vr7 = this.F6.F0;
        var vr9 = Program.s_4;
        var vr10 = this.F1;
        var vr11 = var5[0];
        var vr12 = Program.s_34[0];
        bool vr1 = Program.M49(vr5, vr6, vr7, vr9, vr10, vr11, vr12);
        var vr13 = this;
        return (ushort)Program.M48(vr13);
    }
}

public class C0
{
    public S1 F2;
}

public class Program
{
    public static IRuntime s_rt;
    public static S1 s_4 = new S1(new S0(1));
    public static C0[] s_16 = new C0[]{new C0()};
    public static int[] s_34 = new int[]{0};
    public static void Main()
    {
        s_rt = new Runtime();
        var vr17 = new I2[]{new S1(new S0(0))};
        short vr24 = s_16[0].F2.F1.F1;
        var vr21 = (ulong)vr24;
        ushort vr22 = vr17[0].M47(vr21);
    }

    public static bool M49(S1 arg0, uint arg1, ushort arg2, S1 arg3, S0 arg4, I2 arg5, int arg6)
    {
        arg0 = arg3;
        arg0.F1 = Unsafe.ReadUnaligned<S0>(ref Unsafe.As<uint, byte>(ref arg3.F0));
        s_rt.WriteLine(arg0.F1.F2);
        return arg0.F5;
    }

    public static ref short M48(S1 argThis)
    {
        return ref s_16[0].F2.F1.F1;
    }
}

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

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

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

[jakobbotsch]

Does not repro with DOTNET_JitDoCopyProp=0. Copy prop turns

***** BB01
STMT00000 ( 0x000[E-] ... 0x001 )
N002 ( 19, 13) [000001] DA---------                         ▌  STORE_LCL_VAR struct<S1, 36> V00 arg0         d:2 $VN.Void
N001 (  9,  6) [000000] -----------                         └──▌  LCL_VAR   struct<S1, 36> V03 arg3         u:1 $81

***** BB01
STMT00001 ( 0x003[E-] ... 0x016 )
N002 ( 19, 17) [000007] UA---------                         ▌  STORE_LCL_FLD struct<S0, 12> V00 arg0         ud:2->3[+4] $VN.Void
N001 (  9,  8) [000005] -----------                         └──▌  LCL_FLD   struct<S0, 12> V03 arg3         u:1[+0] (last use) $140

into

***** BB01
STMT00000 ( 0x000[E-] ... 0x001 )
N002 ( 19, 13) [000001] DA---------                         ▌  STORE_LCL_VAR struct<S1, 36> V00 arg0         d:2 $VN.Void
N001 (  9,  6) [000000] -----------                         └──▌  LCL_VAR   struct<S1, 36> V03 arg3         u:1 $81

***** BB01
STMT00001 ( 0x003[E-] ... 0x016 )
N002 ( 19, 17) [000007] UA---------                         ▌  STORE_LCL_FLD struct<S0, 12> V00 arg0         ud:2->3[+4] $VN.Void
N001 (  9,  8) [000005] -----------                         └──▌  LCL_FLD   struct<S0, 12> V00 arg0         u:2[+0] (last use) $140

and codegen does not deal with partially overlapping copies. This is essentially a duplicate of #7539.