Re: likely/unlikely

Jeff Garzik (jgarzik@mandrakesoft.com)
Wed, 16 Jan 2002 00:14:50 -0500

David Schwartz wrote:
>
> By the way, has anybody actually benchmarked these macros to see if they
> make any difference. I did a few quick inexact benchmarks on test code and
> found that in most cases there was no difference and in some cases code was
> made worse.

likely/unlikely set the branch prediction values to 99% or 1%
respectively. If this causes the code generated to perform less
optimally than without, I'm sure the gcc guys would be -very- interested
to hear that...

-- 
Jeff Garzik      | Alternate titles for LOTR:
Building 1024    | Fast Times at Uruk-Hai
MandrakeSoft     | The Took, the Elf, His Daughter and Her Lover
                 | Samwise Gamgee: International Hobbit of Mystery
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