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| author | Andrew Tridgell <tridge@samba.org> | 2009-09-17 09:07:17 -0700 |
|---|---|---|
| committer | Andrew Tridgell <tridge@samba.org> | 2009-09-17 15:19:25 -0700 |
| commit | 6dfd10f476e0b74c36f73bfe17a68ca309c4c5ac (patch) | |
| tree | 527782a69289aebb57d29ac41dcee0b1eacf01e9 | |
| parent | 9e49ad558eb9daaf4df13579211378d8ba01815e (diff) | |
| download | samba-6dfd10f476e0b74c36f73bfe17a68ca309c4c5ac.tar.gz samba-6dfd10f476e0b74c36f73bfe17a68ca309c4c5ac.tar.bz2 samba-6dfd10f476e0b74c36f73bfe17a68ca309c4c5ac.zip | |
libreplace: added likely()/unlikely() macros for gcc
These macros allow the compile to better optimise code that has a lot
of if statements. I particularly want to use this for our low level
generated NDR code.
| -rw-r--r-- | lib/replace/replace.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/replace/replace.h b/lib/replace/replace.h index 2db6aa1226..6424d10c0f 100644 --- a/lib/replace/replace.h +++ b/lib/replace/replace.h @@ -704,4 +704,23 @@ char *ufc_crypt(const char *key, const char *salt); #endif #endif +/* these macros gain us a few percent of speed on gcc */ +#if (__GNUC__ >= 3) +/* the strange !! is to ensure that __builtin_expect() takes either 0 or 1 + as its first argument */ +#ifndef likely +#define likely(x) __builtin_expect(!!(x), 1) +#endif +#ifndef unlikely +#define unlikely(x) __builtin_expect(!!(x), 0) +#endif +#else +#ifndef likely +#define likely(x) (x) +#endif +#ifndef unlikely +#define unlikely(x) (x) +#endif +#endif + #endif /* _LIBREPLACE_REPLACE_H */ |