[Bug tree-optimization/71957] [5/6/7 Regression] Invalid code generation with function static objects

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71957

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hubicka at gcc dot gnu.org
          Component|c++                         |tree-optimization

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
t.C.086t.ccp2:  __builtin_unreachable ();

looks like devirt to me and things go downhill from there.  -fno-devirtualize
fixes it for me.

Honza?

  _9 = OBJ_TYPE_REF(_3;(struct B)&MEM[(void *)&i]->0) (&MEM[(void *)&i],
k_7(D));

is folded to unreachable () inside D::f.

  <bb 3>:
  _11 = __cxa_guard_acquire (&_ZGVZ1gvE1i);
  if (_11 != 0)
    goto <bb 4>;
  else
    goto <bb 5>;

  <bb 4>:
  _12 = f ();
  C<A>::C (&i, _12);
  __cxa_guard_release (&_ZGVZ1gvE1i);

  <bb 5>:
  _2 = MEM[(struct B *)&i]._vptr.B;
  _3 = *_2;
  _9 = OBJ_TYPE_REF(_3;(struct B)&MEM[(void *)&i]->0) (&MEM[(void *)&i],
k_7(D));
  return _9;