Fwd: Re: Branchless implementation for literal case – is it worth it?

Niculae Ionita nicu at ionita.at
Mon Apr 20 17:45:22 UTC 2015


Sorry, I forgot to answer to the list.

If the code is already there and some architectures can profit of it, 
especially in inner loops - why not just make it an optimisation flag?

Nicu

Am 20.04.2015 um 16:41 schrieb Joachim Breitner:
> Hi,
>
> Am Montag, den 20.04.2015, 16:29 +0200 schrieb Sven Panne:
>> 2015-04-19 9:44 GMT+02:00 Joachim Breitner<mail at joachim-breitner.de>:
>>> [...] So my question to the general audience: Is such branchless code really
>>> better than the current, branching code? Can someone provide us with an
>>> example that shows that it is better? Do I need to produce different
>>> branchless assembly? [...]
>> Just a few war stories regarding this from the trenches (= Chrome's
>> JavaScript JIT):
> thanks a lot.
>
> The conclusion I draw from your mail, at last for our case, is:
> Don’t bother (and keep the compiler code simple). Is that a correct
> reading?
>
> Greetings,
> Joachim
>
>
>
>
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