skipping a statemnet from inside a repeating block

[Gopan]

On Thursday, 14 February 2013 at 13:29:07 UTC, John Colvin wrote:

>
> Not internally to the function, no.
>
> In truth, there's no need to do this. Branch prediction 
> (http://en.wikipedia.org/wiki/Branch_predictor) should reduce 
> the cost hugely.
Thank you for the link.  I will see this and come back.

> Also, a comparison is only going to be 1 cycle, saving a single 
> cycle per second is irrelevant.
For iterating through a ranges of indices in a circular way, I 
have seen people coding like

int i=0;
while(true)
{
     ...
     i = (i+1)%10;	
}

People argue i = (i+1)%10 is less costly to the combination below.
++i;
if(i==10)
     i = 0;

If the comparison instruction takes only one cycle, how is this 
argument correct?  Please let me know if that argument is 
incorrect.

Thanks,
Gopan.