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SubjectRe: [PATCH] speed up on find_first_bit for i386 (let compiler do the work)
On Thu, 28 Jul 2005, Linus Torvalds wrote:

> > Since you're considering GCC-generated code for ffs(), ffz() and friends,
> > how about trying __builtin_ffs(), __builtin_clz() and __builtin_ctz() as
> > apropriate?
>
> Please don't. Try again in three years when everybody has them.

Well, __builtin_ffs() has been there since at least gcc 2.95. The two
others are quite recent, indeed -- apparently only since GCC 3.4. They
may still be considered to be used conditionally if there is justified
benefit.

Maciej
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