[Bug c/77989] New: -O3 causes verify_gimple fail

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77989

            Bug ID: 77989
           Summary: -O3 causes verify_gimple fail
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

Created attachment 39814
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39814&action=edit
C source code

The attached C code, when compiled by gcc trunk dated 20161014 and 
compiler flag -O3, does this:

tar.c: In function ‘tar_wr’:
tar.c:554:1: error: invalid address operand in MEM_REF
MEM[(char *)&MEM[(void *)&hdblk + 156B]];

tar.c:554:1: error: invalid first operand of MEM_REF
&MEM[(void *)&hdblk + 156B]
tar.c:300:15: note: in statement
# VUSE <.MEM_505>
_324 = MEM[(char *)&MEM[(void *)&hdblk + 156B]];
tar.c:554:1: internal compiler error: verify_gimple failed
0xd7a849 verify_gimple_in_cfg(function*, bool)
        ../../trunk/gcc/tree-cfg.c:5208
0xbf46fb execute_function_todo
        ../../trunk/gcc/passes.c:1965