See this 1998 discussion between Eliezer and Nick. Some relevant quotes from the thread:

Nick: For example, if it is morally preferred that the people who are currently alive get the chance to survive into the postsingularity world, then we would have to take this desideratum into account when deciding when and how hard to push for the singularity.

Eliezer: Not at all! If that is really and truly and objectively the moral thing to do, then we can rely on the Post-Singularity Entities to be bound by the same reasoning. If the reasoning is wrong, the PSEs won't be bound by it. If the PSEs aren't bound by morality, we have a REAL problem, but I don't see any way of finding this out short of trying it.

Nick: Indeed. And this is another point where I seem to disagree with you. I am not at all certain that being superintelligent implies being moral. Certainly there are very intelligent humans that are also very wicked; I don't see why once you pass a certain threshold of intelligence then it is no longer possible to be morally bad. What I might agree with, is that once you are sufficiently intelligent then you should be able to recognize what's good and what's bad. But whether you are motivated to act in accordance with these moral convictions is a different question.

Eliezer: Do you really know all the logical consequences of placing a large value on human survival? Would you care to define "human" for me? Oops! Thanks to your overly rigid definition, you will live for billions and trillions and googolplexes of years, prohibited from uploading, prohibited even from ameliorating your own boredom, endlessly screaming, until the soul burns out of your mind, after which you will continue to scream.

Nick: I think the risk of this happening is pretty slim and it can be made smaller through building smart safeguards into the moral system. For example, rather than rigidly prescribing a certain treatment for humans, we could add a clause allowing for democratic decisions by humans or human descendants to overrule other laws. I bet you could think of some good safety-measures if you put your mind to it.

Nick: How to contol a superintelligence? An interesting topic. I hope to write a paper on that during the Christmas holiday. [Unfortunately it looks like this paper was never written?]

I assume Bostrom called it something else.

He used "control", which is apparently still his preferred word for the problem today, as in "AI control".