[Bug middle-end/54921] New: [4.8 Regression] wrong code with -Os -fno-omit-frame-pointer -fsched2-use-superblocks -fstack-protector -ftree-slp-vectorize

["zsojka at seznam dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54921

             Bug #: 54921
           Summary: [4.8 Regression] wrong code with -Os
                    -fno-omit-frame-pointer -fsched2-use-superblocks
                    -fstack-protector -ftree-slp-vectorize
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz


Created attachment 28441
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28441
reduced testcase

Output:
$ gcc -Os -fno-omit-frame-pointer -fsched2-use-superblocks -fstack-protector
-ftree-slp-vectorize testcase.c
$ ./a.out 
Aborted

(gdb) p a
$1 = {a = 1, b = '\000' <repeats 31 times>}
(gdb) p b
$2 = {a = 2, b = '\000' <repeats 31 times>}

Tested revisions:
r192420 - fail
4.7 r191640 - OK