patch that caused regression PR optimization/4382

[Janis Johnson]

The regression reported in PR optimization/4382 showed up starting
with this patch:

2000-12-20  Richard Henderson  <rth@redhat.com>

	* rtl.h (REG_NON_LOCAL_GOTO): New.
	* rtl.c (reg_note_name): Update.
	* stmt.c (expand_goto): Emit a REG_NON_LOCAL_GOTO note.
	* builtins.c (expand_builtin_longjmp): Likewise.
	* flow.c (make_edges): Check for REG_NON_LOCAL_GOTO and do
	not emit an edge.

Here's the test case I used, which is in the PR.  There's also a
smaller one in the PR that causes the same ICE.

-------------------
struct jmp_buf {
  void *p[5];
};

static void jumpaway(struct jmp_buf *ptr)
{
  __builtin_longjmp(ptr ,1);
  abort();
}

int main(void)
{
  struct jmp_buf buf;
  if (__builtin_setjmp(&buf) == 0) {
  } else
    return 0;
  jumpaway(&buf);
  abort();
  return 0;
}
-------------------

Output from the compiler when compiled with -O3 using mainline:

4382.c: In function `main':
4382.c:20: error: Wrong amount of branch edges after unconditional jump 0
4382.c:20: internal compiler error: verify_flow_info failed
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://www.gnu.org/software/gcc/bugs.html> for instructions.

I'll add this information to the PR.

Janis