[Bug middle-end/61409] [6 regression] -Wmaybe-uninitialized false-positive with -O2

["law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61409

--- Comment #28 from Jeffrey A. Law <law at redhat dot com> ---
So this is "fixed" on the trunk. 

The trunk now has the ability to track statements that will likely become dead
code as a result of jump threading.  That's enough to get the provided samples
under the code growth limitations.

Of course, all you have to do to is insert a couple more statements that can
not be removed as a result of jump threading and the warning is back.

So I'm leaving state as-is.

For reference, this testcase ought to trigger the problem now.  If growth
limitations are ever changed the test may need further tweaking.


void *init(void);

struct window
{
  int line_height;
  int pixel_width;
  int pixel_height;
  int column_width;
  int text_cols;
  int internal_border_width;
  int left_fringe_width, right_fringe_width;
} *rw;

void bar() __attribute__((noreturn));
void f(int i, int j) {
    void *ptr;
    if (i)
      {
        if (j)
          return; /* bar(); */
        ptr = init();
      }
    rw->pixel_width = ((rw->text_cols * (rw->column_width))
                       + (rw->left_fringe_width + (rw->right_fringe_width)) + 2
* (rw->internal_border_width));
  rw->pixel_height = ((rw->text_cols * (rw->line_height)));
  foo ();
  foo ();
  foo ();
  foo ();
  if (i)
    {
      rw=ptr;
    }
}