[Bug tree-optimization/49115] invalid return value optimization (?) when exception is thrown and caught

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49115

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011.05.22 20:33:26
          Component|c++                         |tree-optimization
         AssignedTo|unassigned at gcc dot       |rguenth at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1
      Known to fail|                            |4.7.0

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-05-22 
20:33:26 UTC ---
Confirmed.  Reduced testcase:

extern "C" void abort (void);
struct MyException {};
struct Data {
    int nr;
    Data() : nr(66) {}
};
Data __attribute__((noinline,noclone)) getData(int i)
{
  if (i) throw MyException();
  Data data;
  data.nr = i;
  return data;
}
int main(int, char **)
{
  Data data;
  try {
      data = getData(1);
  } catch (MyException& e) {
      if (data.nr != 66)
        abort ();
  }
}

what happens is that the store to data.nr from the constructor call in
main is DCEd.  Looks like an alias issue to me.  Mine.