[11] RFR(M): 8203915: Induction variable of over-unrolled loop conflicts with range checks

[Vladimir Kozlov]

Thank you, Tobias, for looking on it.

Then we have to do what you are suggesting. Reviewed.

It is a little frustrating that predicates code become more and more complex and bugs prone :(

Thanks,
Vladimir

On 6/8/18 12:53 AM, Tobias Hartmann wrote:
> Hi Vladimir,
> 
> thanks for looking at this!
> 
> On 07.06.2018 19:18, Vladimir Kozlov wrote:
>> Can you look if PhaseIdealLoop::do_range_check() is executed for main loop in this case? If array
>> length is known statically that code should produce check which should eliminate control flow for
>> main loop and collapse it.
> 
> PhaseIdealLoop::do_range_check() is not executed because after predication, the main loop does not
> contain any range checks (the predicates are before the pre-loop).
> 
> The tests work fine without loop predication (-XX:-UseLoopPredicate) because in this case
> do_range_check() is executed and the corresponding check eliminates control flow as expected.
> 
> Thanks,
> Tobias
>