[Bug tree-optimization/19686] [4.0 Regression] loop performance decrease, not comparing against 0

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-30 
19:52 -------
Actually the conversion to unsigned is free.  The problem is something 
different.

The problem is that we are no longer comparing against 0 instead we are 
comparing something totally 
different.

(ivtmp.2 != (unsigned int) (x - 1) * 65535 + 65535)



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |minor
             Status|UNCONFIRMED                 |NEW
          Component|target                      |tree-optimization
     Ever Confirmed|                            |1
           Keywords|                            |missed-optimization
   Last reconfirmed|0000-00-00 00:00:00         |2005-01-30 19:53:00
               date|                            |
            Summary|avr-gcc 4.0: loop           |[4.0 Regression] loop
                   |performance decrease (extra |performance decrease, not
                   |conversion)                 |comparing against 0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19686