[Bug middle-end/17894] [4.0 Regression] div/compare folding incorrect

Fri Oct 8 19:07:00 GMT 2004

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-08 19:07 -------
Confirmed a regression.
Caused by:
2004-05-08  Roger Sayle  <roger@eyesopen.com> 

        * fold-const.c (fold_div_compare): New function to optimize X/C1 op C2
        where op is a comparison operator and C1 and C2 are integer constants
        into a range check.
        (fold): Call fold_div_compare.

The problem is we are ignoring the sign of C1 which turns around the >= to be <.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |wrong-code
   Last reconfirmed|0000-00-00 00:00:00         |2004-10-08 19:07:36
               date|                            |
            Summary|[miscompile] div/compare    |[4.0 Regression] div/compare
                   |folding incorrect           |folding incorrect
   Target Milestone|---                         |4.0.0

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17894