[Bug middle-end/116290] [12/13/14/15 regression] -fcompare-debug -gno-statement-frontiers -O2 failure with evolution-data-server-3.52.4

[sjames at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116290

--- Comment #2 from Sam James <sjames at gcc dot gnu.org> ---
Reduced:
```
char *camel_message_info_class_intern_init_part;
void g_once_init_enter();
void camel_message_info_class_intern_init() {
  int ii;
  char *label;
  for (; camel_message_info_class_intern_init_part[ii]; ii++)
    if (camel_message_info_class_intern_init_part) {
      if (label && *label)
        g_once_init_enter();
      label = &camel_message_info_class_intern_init_part[ii + 1];
      camel_message_info_class_intern_init_part[ii] = ' ';
    }
  if (label)
    g_once_init_enter();
}
```