Bound check with uint casts no longer elided

[MihaZupan]

public static int Foo(string str)
{
    int length = str.Length;
    
    while ((uint)(length - 1) < (uint)str.Length && str[length - 1] == ' ')
    {
        length--;
    }
    
    return length;
}

public static int Bar(string str)
{
    int length = str.Length;
    
    while (length > 0 && str[length - 1] == ' ')
    {
        length--;
    }
    
    return length;
}

In .NET 9, Foo elided the extra bounds check, but godbolt is showing it again on main https://godbolt.org/z/qnYEzcdne.

Bar also seems like something where the JIT could prove that an extra check isn't needed.

[dotnet-policy-service]

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