[Bug tree-optimization/46969] New: -O -ftree-vectorize -ftree-parallelize-loops=2 -fcompare-debug

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46969

           Summary: -O -ftree-vectorize -ftree-parallelize-loops=2
                    -fcompare-debug
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
                CC: aoliva@gcc.gnu.org
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 22772
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22772
reduced testcase (from gcc.dg/vect/pr44507.c)

This problem seems to be quite fragile.

$ gcc -O -ftree-vectoriztree-parallelize-loops=2 -fcompare-debug pr46969.c 
gcc: error: pr46969.c: -fcompare-debug failure (length)

Tested revisions:
r167809 - fail
r165699 - fail
r161659 - OK
4.5 r166509 - OK