why not optimize static local variables

[Hanke Zhang via Gcc]

Hi, I've recently been working on static local variables in C. I would
like to ask about some questions about that.

For example, for the following program,

void foo() {
  static int x = 0;
  x++;
}

int main() {
  foo();
}

After optimization with the -O3 -flto option, the entire program will
look something like this:

int main() {
  x_foo++;
}

The question I want to ask is, why not optimize the 'x_foo++' line of
code out? Because its scope will only be in foo, and it will not be
read at all for the entire program. Is it because it is stored in the
global data area? Or are there other security issues?

Thanks
Hanke Zhang