[Bug c/76783] [7 Regression] wrong code with conditional vector assignment @ -Og

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=76783

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2016-08-15
          Component|rtl-optimization            |c
   Target Milestone|---                         |7.0
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  Note that I think the vector construction doesn't work already. 
From
the .gimple dump:

foo (unsigned int c, v64u128 v)
{
  u128 D.1767;
  v64u128 u;

  try
    {
      if (c != 0) goto <D.1764>; else goto <D.1765>;
      <D.1764>:
      u = { 0, 0, 0, 0 };
      goto <D.1766>;
      <D.1765>:
      u = { 0, 1, 0, 0 };
      <D.1766>:
      u.0_1 = u;
      _2 = v + u.0_1;
      u = _2;
      D.1767 = BIT_FIELD_REF <u, 128, 128>;
      return D.1767;

here the upper __int128 in the vector is obviously zero.  Somehow a mix-up
somewhere.