[Bug c/26367] multiple levels of __builtin_expect

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26367

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2017-02-16
                 CC|                            |msebor at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #8 from Martin Sebor <msebor at gcc dot gnu.org> ---
As noted in comment #7 the three levels are provided by a combination of
__builtin_expect and __builtin_unreachable, for example like so:

  void f_n (void);
  void f_p (void);
  void f_0 (void);

  void f (int i)
  {
    if (__builtin_expect (i < 0, 0)) __builtin_unreachable ();   // certain
    if (__builtin_expect (i == 0, 0)) f_0 ();   // weak
    if (__builtin_expect (i > 0, 1)) f_p ();    // strong
  }

Is there anything else that's not covered by these two built-ins or can this
bug be resolved?