http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56595
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2013-03-11
Blocks| |53947
Ever Confirmed|0 |1
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> 2013-03-11
14:25:02 UTC ---
Confirmed (and known). See inhibit_phi_insertion in PRE.
I bet you find some duplicate in the list of missed-vectorization bugs.
Loop store-motion can result in similar issues.
Note that an issue with limiting things even further is that PRE is limited
even when the resulting loop is _not_ vectorized. Which is of course bad.
So the best solution is to teach the vectorizer to handle this kind of
dependency (after all user code can be written in that way from the start).
