In any "fly by wire" aircraft, such as the A330 enables the pilot to override the computer/auto flight system. While I'm sure it's never been done, the fact is that any well executed loop manuever never imposes more than one "G" force on the aircraft. The speed is not a concern as long as the air speed is managed.
Years ago, when the Boeng 707, one of the first jet transport aircraft was being test flown, a group of potential airline buyers of the aircraft was concerned about the "new" technology. (The British were the first with the Comet, with disatrous results). The test pilot "Tex" Johnson elected to demonstrate a roll in the huge aircraft. It was actually filmed... see here:
https://www.youtube.com/watch?v=Ra_khhzuFlE
I had the distinct honor to meet Mr. Johnson... He would have no compuntion in looping an A330, I sure...