JIT: Redundant range check

[rameel]

https://godbolt.org/z/KMPGzdnv5

public static string? TryUnwrapPrefix(string prefix, string path)
{
    if (prefix == "/")
        return path;

    if (path == prefix)
        return "/";

    if ((uint)prefix.Length < (uint)path.Length)
        if (path.StartsWith(prefix, StringComparison.Ordinal))
            if (path[prefix.Length] == '/')
                return new string(path.AsSpan(prefix.Length));

    return null;
}

Compiled with an unnecessary range check.

If one of the initial if statements is removed or the (uint)prefix.Length < (uint)path.Length check is moved after path.StartsWith then the JIT correctly eliminates the redundant bounds check.

---

This optimization works as expected in .NET 8-10

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