JIT: OSR is not conservative enough about exposing struct locals

[jakobbotsch]

using System;
using System.Runtime.CompilerServices;

public class MissingExposure
{
    [MethodImpl(MethodImplOptions.NoInlining)]
    static void Bar()
    {
    }

    [MethodImpl(MethodImplOptions.NoInlining)]
    static void Foo(int n)
    {
        S s = new S { F = 1234 };
        ref int foo = ref s.F;

        for (int i = 0; i < n; i++)
        {
            Bar();
        }

        int abc = s.F * 3 + 4;
        foo = 25;
        int def = s.F * 3 + 4;
        Console.WriteLine("abc = {0} (expected {1}), def = {2} (expected {3})", abc, 1234 * 3 + 4, def, 25 * 3 + 4);
    }

    public static void Main()
    {
        Foo(50000);
    }

    public struct S
    {
        public int F;
    }
}

Output with OSR enabled: abc = 3706 (expected 3706), def = 3706 (expected 79)

cc @AndyAyersMS

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Issue Details

---

using System;
using System.Runtime.CompilerServices;

public class MissingExposure
{
    [MethodImpl(MethodImplOptions.NoInlining)]
    static void Bar()
    {
    }

    [MethodImpl(MethodImplOptions.NoInlining)]
    static void Foo(int n)
    {
        S s = new S { F = 1234 };
        ref int foo = ref s.F;

        for (int i = 0; i < n; i++)
        {
            Bar();
        }

        int abc = s.F * 3 + 4;
        foo = 25;
        int def = s.F * 3 + 4;
        Console.WriteLine("abc = {0} (expected {1}), def = {2} (expected {3})", abc, 1234 * 3 + 4, def, 25 * 3 + 4);
    }

    public static void Main()
    {
        Foo(50000);
    }

    public struct S
    {
        public int F;
    }
}

Output with OSR enabled: abc = 3706 (expected 3706), def = 3706 (expected 79)

cc @AndyAyersMS

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