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

    > I've been playing with different approaches, (still all hot cache
    > though), and inspecting the generated code. It's not that the gcc
    > generated code is always better for the normal case. But since it sees
    > more and everything is not hidden in asm, it can optimise what is being
    > used, and how it's used.

    Since you're considering GCC-generated code for ffs(), ffz() and friends,
    how about trying __builtin_ffs(), __builtin_clz() and __builtin_ctz() as
    apropriate? Reasonably recent GCC may actually be good enough to use the
    fastest code depending on the processor submodel selected.

    Maciej
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