[Bug optimization/13653] New: [3.3 regression] -O2 -funroll-loop miscompiles POOMA testcase

[rguenth at tat dot physik dot uni-tuebingen dot de]

Current g++-3.3 (g++-3.3 (GCC) 3.3.3 20040107 (prerelease)) miscompiles quite a
few POOMA testcases which results in SIGSEGVs.  These failures occour with -O2
-funroll-loops, but not with -O2.

One example preprocessed testcase can be fetched from
http://www.tat.physik.uni-tuebingen.de/~rguenth/gcc/array_test1.ii.gz

compile with -fno-exceptions -O2 -funroll-loops to see it segfaulting and with
-fno-exceptions -O2 to see it printing a success message.

g++ (GCC) 3.3.3 20031114 (prerelease) also did have this problem (this is the
oldest binary I have lying around).

-- 
           Summary: [3.3 regression] -O2 -funroll-loop miscompiles POOMA
                    testcase
           Product: gcc
           Version: 3.3.3
            Status: UNCONFIRMED
          Severity: critical
          Priority: P2
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at tat dot physik dot uni-tuebingen dot de
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13653