[Bug sanitizer/66908] Uninitialized variable when compiled with UBsan

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66908

--- Comment #10 from Maxim Ostapenko <chefmax at gcc dot gnu.org> ---
(In reply to Marek Polacek from comment #9)
> Oh silly me!  This should work; Maxim, could you possibly try this patch?

Sorry, Marek, nothing changed for C++ testcase:

      D.6137 = get.__delta;
      D.6138 = D.6137 & 1;
      if (D.6138 == 0) goto <D.6139>; else goto <D.6140>;
  <D.6139>:
      iftmp.1 = get.__pfn;
      goto <D.6141>;
  <D.6140>:
      A.2 = A;
      D.6143 = get.__delta;
      D.6144 = D.6143 >> 1;
      D.6145 = (sizetype) D.6144;
      D.6146 = A.2 + D.6145;
      D.6147 = MEM[(int (*__vtbl_ptr_type) () * *)D.6146];
      D.6148 = get.__pfn;
      D.6149 = (sizetype) D.6148;
      D.6150 = D.6147 + D.6149;
      iftmp.1 = *D.6150;
  <D.6141>:
      A.3 = A;
      D.6152 = D.6143 >> 1;
      D.6153 = (sizetype) D.6152;
      D.6154 = A.3 + D.6153;
      result = iftmp.1 (D.6154);