[Bug libstdc++/109442] Dead local copy of std::vector not removed from function

[hubicka at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109442

--- Comment #23 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
with Jakub's builtion_operator_new patch and
https://gcc.gnu.org/pipermail/gcc-patches/2024-November/667834.html
on the original testcase we now optimize away allocation and produce

int vat1 (struct vector & v1)
{
  unsigned long _9;
  int * _13;
  int * _14;
  long int _15;

  <bb 2> [local count: 1073741824]:
  _13 = MEM[(const struct vector *)v1_2(D)].D.34245._M_impl.D.33558._M_finish;
  _14 = MEM[(const struct vector *)v1_2(D)].D.34245._M_impl.D.33558._M_start;
  _15 = _13 - _14;
  _9 = (unsigned long) _15;
  if (_9 > 9223372036854775804)
    goto <bb 3>; [54.67%]
  else
    goto <bb 4>; [45.33%]

  <bb 3> [local count: 587014656]:
  std::__throw_bad_array_new_length ();

  <bb 4> [local count: 1015040358]:
  return 10;

}

So I guess we are missing somewhere __builtin_assert that the length of vector
copied is allways smaller then half of address space...