http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56273
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |diagnostic,
| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2013-02-10
Component|other |tree-optimization
Ever Confirmed|0 |1
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2013-02-10
07:34:54 UTC ---
The problem is a missing VRP. Basically ivopts changes:
if (j_10 != 9)
Which works into:
j_10 = ivtmp.12_56;
if (ivtmp.12_56 != 9)
goto <bb 7>;
else
goto <bb 6>;
Which does not work as VRP cannot figure out j_10 will never be 9.
I have some patches to VRP which improves this but I don't remember if it fixes
this case where there is an assignment which is used later on.
