commit 91998e449e0ce758db55aecf2abc3ee510fcbc8f
Author: Siddhesh Poyarekar <siddhesh@redhat.com>
Date:   Fri Dec 28 11:53:01 2012 +0530

    Add __glibc_likely as an alias for __builtin_expect when available

diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index fb6c959..1eee54e 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -378,8 +378,10 @@
 
 #if __GNUC__ >= 3
 # define __glibc_unlikely(cond) __builtin_expect((cond), 0)
+# define __glibc_likely(cond) __builtin_expect((cond), 1)
 #else
 # define __glibc_unlikely(cond) (cond)
+# define __glibc_likely(cond) (cond)
 #endif
 
 #include <bits/wordsize.h>