RFR(S): 8202950: C2: assert(found_sfpt) failed: no node in loop that's not input to safepoint

[Vladimir Kozlov]

Good. Reviewed.
Thank you Roland for explaining 

Thanks
Vladimir

> On May 18, 2018, at 8:51 AM, Roland Westrelin <rwestrel at redhat.com> wrote:
> 
> 
>> Last question: why you check IgnoreStripMined?
>> 
>> Why is_strip_minned() check is not enough?
> 
> mode == IgnoreStripMined is when cloning is performed for unrolling. In
> that case, the control flow that joins the inner loop and its clone
> together has a region right outside the inner loops, in the outer
> loop. When mode != IgnoreStripMined (pre/post loop construction,
> unswitching, peeling), the region is outside at least one outer
> loop. Then if a load is outside both loops with control in the inner
> loop, its control will be set to that region right outside the outer loop
> and the verification code won't fail.
> 
> Roland.