[Bug tree-optimization/21029] New: vrp miscompiles Ada front-end, drops loop exit test in well-defined wrap-around circumstances

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

csets___elabb gets miscompiled in stage2, such that stage3 enters and endless
loop compiling ada.ads.  Unfortunately, vrp seldom kicks in, so it's a bit
difficult to duplicate the problem.  Perhaps it would make sense to add a
command-line option to force vrp on, and add that to torture, just to see how it
goes?

-- 
           Summary: vrp miscompiles Ada front-end, drops loop exit test in
                    well-defined wrap-around circumstances
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: dnovillo at gcc dot gnu dot org
        ReportedBy: aoliva at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21029