[Bug c++/87862] Different behavior with -O2 with template specialization of virtual member function

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87862

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This looks like undefined behaviour. You have a template specialization in
s.cpp but none of the other files can see that specialization exists, and so
they implicitly instantiate t<z::e>::get_b based on the primary template, which
returns a null pointer, which you dereference.