[Bug middle-end/100861] False positive -Wmismatched-new-delete with destroying operator delete

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100861

--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
The virtual dtor forces an out-of-line call to the Grommet dtor which then
calls ::operator delete(), so the warning has nothing to complain about.  It
sees this code (compile with -fdump-tree-optimized=/dev/stdout):

int main ()
{
  void * _3;

  <bb 2> [local count: 1073741824]:
  _3 = operator new (16);
  MEM[(struct Widget *)_3].Kind = 0;
  MEM[(struct Grommet *)_3].D.2504._vptr.Widget = &MEM <int (*) ()[4]> [(void
*)&_ZTV7Grommet + 16B];
  Grommet::~Grommet (_3);
  return 0;

}

whereas with the original test case it sees:

int main ()
{
  struct destroying_delete_t D.2584;
  void * _3;

  <bb 2> [local count: 1073741824]:
  _3 = operator new (4);
  Widget::operator delete (_3, D.2584);   <<< warning here
  return 0;

}