[Bug target/79671] [7 Regression] mapnik miscompilation on armv7hl since r235622

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79671

--- Comment #19 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The MEM[(struct parser_binder *)&D.614964 + 4B] = f;'s ultimate origin is:
if (D.589607 != 0B)
  {
    iftmp.77 = try
      {
        MEM[(struct parser_binder *)D.589607] = f;
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This stmt
      }
    catch
      {
        operator delete (D.589607, NON_LVALUE_EXPR <D.589606>);
      }, (struct parser_binder *) D.589607;;
  }
else
  {
    iftmp.77 = (struct parser_binder *) D.589607;
  }

from:
        template<typename FunctionObj>
        void
        assign_functor(FunctionObj f, function_buffer& functor, mpl::true_)
const
        {
          new (reinterpret_cast<void*>(&functor.data)) FunctionObj(f);
        }
which looks like a placement new into that mutable char data; field of
boost::detail::function::function_buffer, and then the whole union is copied
including the placement new created data in there.  No idea if that is valid
C++.