Messages in this thread |  | | Subject | Re: Linux 2.4.10-pre11 -- __builtin_expect | From | James Antill <> | Date | 26 Sep 2001 19:54:59 -0400 |
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Andi Kleen <ak@suse.de> writes:
> Good point. I somehow assumed that __builtin_expect would just signify > a boolean, but if I read gcc source correctly this was wrong.
Yeh, it's a long so you'll get no cast warnings too.
> Here is an updated patch.
[snip ... ]
> --- include/linux/kernel.h-LIKELY Tue Sep 18 11:12:20 2001 > +++ include/linux/kernel.h Tue Sep 18 14:35:17 2001 > @@ -171,4 +171,14 @@ > char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */ > }; > > + > +/* This loses on a few early 2.96 snapshots, but hopefully nobody uses them anymore. */ > +#if __GNUC__ > 2 || (__GNUC__ == 2 && _GNUC_MINOR__ == 96) > +#define likely(x) __builtin_expect(!!(x), 1) > +#define unlikely(x) __builtin_expect((x), 0)
unlikely() also needs to be...
#define unlikely(x) __builtin_expect(!(x), 1)
...or...
#define unlikely(x) __builtin_expect(!!(x), 0)
> +#else > +#define likely(x) (x) > +#define unlikely(x) (x) > +#endif > + > #endif
-- # James Antill -- james@and.org :0: * ^From: .*james@and\.org /dev/null - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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