https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79671
--- Comment #23 from Richard Biener <rguenth at gcc dot gnu.org> --- (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.
