What technical merit is it to write this boolean return condition explicitly as if-else?

Question

What technical merit is it to write this boolean return condition explicitly as if-else?

I was looking at the double

implementation from the original source and saw the following function definition:

[Pure]
[System.Runtime.Versioning.NonVersionable]
public static bool IsPositiveInfinity(double d) {
    //Jit will generate inlineable code with this
    if (d == double.PositiveInfinity)
    {
        return true;
    }
    else
    {
        return false;
    }
}

The commentary in this passage caught my attention. It says:

Jit will generate inline code with this

It looks like the developer expects the next statement to if

affect inlining and as a result selects this one line at a time return

. I understand the concept of JIT-inlining (at least I thought I did), but I don't see how the "if" construct relates to such an operation.