[Bug tree-optimization/35292] Missing Const Prop -- union fields

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35292

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to work|                            |4.7.0
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0
      Known to fail|                            |4.6.4

--- Comment #6 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-07-05 
14:05:00 UTC ---
This is fixed in 4.7, done by FRE1:

Replaced u.cc.c[0] with 20 in D.1722_1 = u.cc.c[0];
Replaced (int) D.1722_1 with 20 in D.1723_2 = (int) D.1722_1;
Replaced u.cc.c[1] with 0 in D.1724_3 = u.cc.c[1];
Replaced (int) D.1724_3 with 0 in D.1725_4 = (int) D.1724_3;
Replaced D.1723_2 + D.1725_4 with 20 in D.1721_5 = D.1723_2 + D.1725_4;
foo (int i)
{
  int D.1725;
  char D.1724;
  int D.1723;
  char D.1722;
  int D.1721;

<bb 2>:
  u.ii = 20;
  D.1722_1 = 20;
  D.1723_2 = 20;
  D.1724_3 = 0;
  D.1725_4 = 0;
  D.1721_5 = 20;
  return D.1721_5;
}