There use to be a time when reshoots were a signal that a film was in big trouble. The thought was that reshoots were usually the result of studio executives or a test screening audience having problems with a film.
However, nowadays, it seems like reshoots have become commonplace with a film. Sometimes reshoots are simply a way to put more focus on something or someone that stands out in a film, such as the Thor: The Dark World reshoots to add more Loki.
According to the Calgary Herald, X-Men: Days Of Future Past is returning to Montreal in a couple weeks for reshoots. Director Bryan Singer and some of the cast and crew of X-Men: Days Of Future Past will reportedly be shooting for a couple weeks, so it sounds like it is a fairly significant reshoot.
X-Men: Days Of Future Past is scheduled to be released in movie theaters on May 23, 2014.