[Bug tree-optimization/25148] New: compare_values assumes that CST in a + CST (and a - CST) is always postive

["pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

I am filing this right now even though I don't have a testcase because I am
running into it while trying to fix PR 23666.  I don't know if this will cause
wrong code or not.  I do know it will cause a missed optimization while
compiling "g++.dg/tree-ssa/pr18178.C"  I have to find a testcase which fails
currently.


-- 
           Summary: compare_values assumes that CST in a + CST (and a - CST)
                    is always postive
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25148