https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106965
--- Comment #4 from Boaz <olddra3rd at mozmail dot com> --- (In reply to Jonathan Wakely from comment #3) > (In reply to Richard Biener from comment #1) > > I think it's undefined to invoke a DTOR twice which is what you do here. > > After the DTOR the m_ptr member becomes undefined so re-evaluating that in > > the second invocation (when there's no object of type X anymore) is > > undefined. > > Right, and because you can't ever use the m_ptr member after the destructor, > there's no point writing the 0 to it. That's a dead store, so the compiler > is allowed to eliminate it. A correct program can never observe whether that > store happened or not. My logic in assigning 0 was preventing delete on a dangling pointer in case of a double call to a destructor (for example, if the object was dynamically allocated) which is a good practice as far as I know. But my mistake was indeed calling a destructor explicitly on an automatic storage, quoting from ISO2020: "If a variable with automatic storage duration has initialization or a destructor with side effects, an implemen- tation shall not destroy it before the end of its block nor eliminate it as an optimization, even if it appears to be unused, except that a class object or its copy/move may be eliminated as specified in 11.10.6." So... my bad.
