[Bug c/47892] Fails to vectorize comparison code, if-conversion fails

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47892

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.02.25 10:22:06
                 CC|                            |rguenth at gcc dot gnu.org,
                   |                            |spop at gcc dot gnu.org
            Summary|Fails to vectorize          |Fails to vectorize
                   |comparison code             |comparison code,
                   |                            |if-conversion fails
     Ever Confirmed|0                           |1

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-02-25 
10:22:06 UTC ---
We vectorize on trunk with -fno-tree-pre and float constants.  Without
-fno-tree-pre if-conversion is confused and on the 4.5 branch it doesn't
if-convert

  if (or_10 > 5.2359879016876220703125e-1)
    goto <bb 7>;
  else
    goto <bb 8>;

<bb 7>:

<bb 8>:
  # iftmp.1_3 = PHI <1.0e+0(7), 0.0(6)>