[Bug tree-optimization/109170] New glibc warning: open_catalog.c:86:16: error: pointer ‘old_buf’ may be used after ‘realloc’ [-Werror=use-after-free] since r13-6707-g0a07bfad12530bca

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109170

--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Reduced test-case:

$ cat open_catalog.i
unsigned long bufmax = 0;
unsigned long __open_catalog_bufmax;
void *realloc();
void free();

void __open_catalog(char *buf) {
  char *old_buf = buf;
   buf = realloc (buf, bufmax);
   if (__builtin_expect ((buf == ((void *)0)), 0))
     free (old_buf);
}