Messages in this thread |  | | Subject | Re: Linux 2.4.10-pre11 -- __builtin_expect | From | Andreas Schwab <> | Date | 27 Sep 2001 18:28:08 +0200 |
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James Antill <james@and.org> writes:
|> Andreas Schwab <schwab@suse.de> writes: |> |> > James Antill <james@and.org> writes: |> > |> > |> unlikely() also needs to be... |> > |> |> > |> #define unlikely(x) __builtin_expect(!(x), 1) |> > |> |> > |> ...or... |> > |> |> > |> #define unlikely(x) __builtin_expect(!!(x), 0) |> > |> > This is not needed, since only 0 is the likely value and !! does not |> > change that. |> |> Yes it is, given the code... |> |> struct blah *ptr = NULL; |> |> if (unlikely(ptr)) |> |> ...you'll get a warning from gcc because you are implicitly converting |> from a pointer to a long.
You're right, seems like __builtin_expect is really only defined for pure boolean values.
Andreas.
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