[Bug rtl-optimization/97783] Optimizer assumes global static variable cannot be updated by external function, even though function is passed address of local functions

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97783

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2020-11-11
           Keywords|                            |wrong-code
                 CC|                            |hubicka at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  It's IPA reference that does not appropriately make the "local"
function gl_lstat global when it escapes in main to glob().

For some reason it doesn't reproduce with the simple

TU1:

void foo(void (**fn)())
{
  (*fn)();
}

TU2:

static int x;
static void bar() { x = 1; }
extern void foo(void (**)());
int
main ()
{
  void (*ptr)() = bar;
  x = 0;
  foo(&ptr);
  if (x != 1)
    __builtin_abort ();
  return 0;
}