[Bug c/47001] New: segmentation fault in vect_mark_slp_stmts

["dcb314 at hotmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47001

           Summary: segmentation fault in vect_mark_slp_stmts
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: dcb314@hotmail.com


Created attachment 22808
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22808
C source code

I just tried to compile package groonga-1.0.3 with the latest 4.6
snapshot 20101211 on a Fedora Linux box. The compiler said

io.c: In function 'grn_io_open':
io.c:402:12: warning: variable 'flags' set but not used
[-Wunused-but-set-variable]
io.c:397:1: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

valgrind says

==8475== Invalid read of size 4
==8475==    at 0x92FA3D: vect_mark_slp_stmts (tree-vect-slp.c:2597)
==8475==    by 0x932443: vect_make_slp_decision (tree-vect-slp.c:1347)
==8475==    by 0x928F80: vect_analyze_loop (tree-vect-loop.c:1497)
==8475==    by 0x935647: vectorize_loops (tree-vectorizer.c:199)
==8475==    by 0x74510E: execute_one_pass (passes.c:1553)
==8475==    by 0x7453B4: execute_pass_list (passes.c:1608)
==8475==    by 0x7453C6: execute_pass_list (passes.c:1609)
==8475==    by 0x7453C6: execute_pass_list (passes.c:1609)
==8475==    by 0x838CD5: tree_rest_of_compilation (tree-optimize.c:422)
==8475==    by 0x9D6540: cgraph_expand_function (cgraphunit.c:1508)
==8475==    by 0x9D8AA9: cgraph_optimize (cgraphunit.c:1567)
==8475==    by 0x9D9019: cgraph_finalize_compilation_unit (cgraphunit.c:1031)
==8475==  Address 0x4 is not stack'd, malloc'd or (recently) free'd
==8475==

Source code attached. Flag -O3 required.