[Bug ipa/60965] [4.10 Regression] IPA: Devirtualization versus placement new

["redi at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60965

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-04-25
      Known to work|                            |4.8.2, 4.9.0
            Summary|IPA: Devirtualization       |[4.10 Regression] IPA:
                   |versus placement new        |Devirtualization versus
                   |                            |placement new
     Ever confirmed|0                           |1

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Self-contained reproducer, using -std=c++11 -O2

#include <new>

class EmbeddedObject {
public:
  virtual int val() { return 2; }
};

class Container {
  alignas(EmbeddedObject) char buffer[sizeof(EmbeddedObject)];
public:
  EmbeddedObject *obj() { return (EmbeddedObject*)buffer; }
  Container() { new (buffer) EmbeddedObject(); }
};

Container o;

int main()
{
  __builtin_printf("%d\n", o.obj()->val());
}