https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26366
sandra at gcc dot gnu.org changed:
What|Removed |Added
Status|NEW |RESOLVED
CC|
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26366
--- Comment #6 from sandra at gcc dot gnu.org ---
Author: sandra
Date: Sun Nov 11 18:39:10 2018
New Revision: 266017
URL: https://gcc.gnu.org/viewcvs?rev=266017&root=gcc&view=rev
Log:
2018-11-11 Sandra Loosemore
PR c/26366
gc
--- 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 ti
--- 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
--- Comment #3 from pinskia at gcc dot gnu dot org 2006-02-20 02:06 ---
x86 is forgiving because there is no such bit that is used (well except for the
prescott and GCC disables it because it was a wash and used up space).
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26366
--- Comment #2 from acahalan at gmail dot com 2006-02-19 21:48 ---
Nope, at least if the documentation at
http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html is what you refer to.
It would be good to document how strong the expectation is for each
architecture. Apparently the differe
--- Comment #1 from pinskia at gcc dot gnu dot org 2006-02-19 20:25 ---
I thought the documention said only to use __builtin_expect when you know that
in almost 100% of the time it is going to be true (or false).
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26366
