https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79671
--- Comment #24 from Bernd Edlinger <bernd.edlinger at hotmail dot de> --- (In reply to Richard Biener from comment #23) > (In reply to Bernd Edlinger from comment #22) > > (In reply to Jakub Jelinek from comment #20) > > > which fails also on x86_64-linux at -O2. And that testcase regressed with > > > r223126. Now whether this is valid C++, no idea, placement new is messy. > > > > This test case can't be valid, suppose the A has a copy constructor > > that that is also not called when B is moved around. > > The canonical fix is to put the type you placement new into the union storage > into the union as regular member rather than having a char[] member in the > union. Yes. Of course you cannot put a non-POD type in a union, but maybe a pointer to A, that is probably what boost should do in their functor class.
