[Bug c/79432] New: ICE: verify_ssa failed

[gerhard.steinmetz.fortran@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79432

            Bug ID: 79432
           Summary: ICE: verify_ssa failed
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gerhard.steinmetz.fortran@t-online.de
  Target Milestone: ---

Seen with version 7 only, on x86_64 GNU/Linux.
(not depending on any options)


$ cat z1.c
int fn1 (void);
int vfork (void);
void fn2 ()
{
  int a;
  a = fn1() + vfork();
}


$ gcc-6 -c z1.c
$ gcc-7-20170205 -c z1.c
z1.c: In function 'fn2':
z1.c:7:1: error: definition in block 3 does not dominate use in block 6
 }
 ^
for SSA_NAME: _1 in statement:
a_10 = _1 + _2;
z1.c:7:1: internal compiler error: verify_ssa failed
0xe10883 verify_ssa(bool, bool)
        ../../gcc/tree-ssa.c:1184
0xb167fd execute_function_todo
        ../../gcc/passes.c:1973
0xb170e5 execute_todo
        ../../gcc/passes.c:2016