[Bug tree-optimization/100171] autovectorizer

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100171

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Compared to the non-self case where we see

  <bb 2> [local count: 357878152]:
  _19 = MEM <const double[2]> [(const value_type &)arg1_3(D)][0];
  _20 = MEM <const double[2]> [(const value_type &)arg2_4(D)][0];
  _21 = _19 + _20;
  _26 = MEM <const double[2]> [(const value_type &)arg1_3(D)][1];
  _27 = MEM <const double[2]> [(const value_type &)arg2_4(D)][1];
  _28 = _26 + _27;
  res ={v} {CLOBBER};
  MEM[(struct value_type *)out_2(D)][0].value._M_elems[0] = _21;
  MEM[(struct value_type *)out_2(D)][0].value._M_elems[1] = _28;
  return;

here intermediate optimizations have elided 'res'.