[Bug tree-optimization/35229] Vectorizer doesn't support dependence created by predictive commoning

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2009-02-25 14:12 -------
Indeed.  Proper testcase:

float res[1024], data[1024];

void foo(void)
{
  int i;
  float tmp = data[0];
  for (i = 1; i < 1024; ++i)
    {
      float tmp2 = data[i];
      res[i] = tmp + tmp2;
      tmp = tmp2;
    }
}

manually "optimized" from

      res[i] = data[i] + data[i-1];


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org
OtherBugsDependingO|                            |39300
              nThis|                            |
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-02-25 14:12:51
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35229