[Bug c/26366] __builtin_expect needs better documentation

["acahalan at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #5 from acahalan at gmail dot com  2006-02-22 03:14 -------
The code in comment #4 really isn't the same as the original. The original is a
decorated version of this:

if(x && y)

It is meant to express that:

x is likely
y is likely
x&&y is unlikely

Here, the probability of x times the probability of y is less than 0.5 even
though the probability of x and the probability of y are both greater than 0.5.

Nothing says that standalone __builtin_expect() calls should have no effect.
This can be much more readable than using the calls in a test.


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