[Bug tree-optimization/20134] New: 176.gcc miscompare with -m64 after DOM change

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

The SPEC CPU2000 test 176.gcc has been failing on powerpc64-*-linux-gnu
with "-m64 -O1" since this patch was added:
                                                                               
                
2004-10-23  Daniel Berlin  <dberlin@dberlin.org>
                                                                               
                
        * tree-ssa-dom.c (record_equality): Use loop depth to determine
        which way to record the equality as well.
        (loop_depth_of_name): New function.
                                                                               
                
The failure goes away if the patch is reverted from mainline sources.
                                                                               
                
The miscompare is due to function exact_log2_wide from toplev.c in
176.gcc, which returns 63 instead of 31 for the value -2147483648.
I'll attach a testcase with that function.

-- 
           Summary: 176.gcc miscompare with -m64 after DOM change
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: janis at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20134