[Bug c/26366] __builtin_expect needs better documentation

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2006-02-21 09:57 -------
Another way instead of

if(__builtin_expect((__builtin_expect(x,1) && __builtin_expect(y,1)), 0))

would be

if(__builtin_expect(!(x && y), 1))

I'm sure this does _not_ result in same behavior as __builtin_expect is
evaluated
quite late during compilation.  Some clarification in the docs would be really
nice.

As to standalone __builtin_expect() calls, they should have no effect.  There
was talking about a __builtin_assert() or __builtin_assume() that would force
a known value.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-02-21 09:57:21
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26366