RFR(S): 8085832: Optimize main and post loop out when pre loop is found empty

[Roland Westrelin]

Thanks for the review, Vladimir.

Roland.

> On Jun 4, 2015, at 5:53 PM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
> 
> Looks fine.
> 
> Thanks,
> Vladimir
> 
> On 6/4/15 7:54 AM, Roland Westrelin wrote:
>> http://cr.openjdk.java.net/~roland/8085832/webrev.00/
>> 
>> This is the change I proposed as a fix for 8078866.
>> 
>> Roland.
>>