RFR(S): 8231550: C2: ShouldNotReachHere() in verify_strip_mined_scheduling

[Tobias Hartmann]

+1

All testing that Vladimir submitted passed.

Best regards,
Tobias

On 04.10.19 17:15, Vladimir Ivanov wrote:
> Looks good.
> 
> (Submitted for testing.)
> 
> Best regards,
> Vladimir Ivanov
> 
> On 03/10/2019 11:48, Roland Westrelin wrote:
>>
>> http://cr.openjdk.java.net/~roland/8231550/webrev.00/
>>
>> This is another case where too conservative alias analysis pushes a load
>> in the outer strip mined loop and causes loop strip mining verification
>> to fail. The regression test contains two subtests. In both cases, a
>> load (either of the array length or of a field) depends on a CastPP
>> that's control dependent on the counted loop. A store that's unrelated
>> is sunk in the outer strip mined loop. Because the load can't float
>> above the counted loop and because anti dependence analysis is too
>> conservative, the load ends up in the outer strip mined loop. I see no
>> way around this one other than to relax anti dependence analysis.
>>
>> This also causes my recent fix for Shenandoah bug 8231761 to fail
>> (because it relied on anti-dependence analysis to be conservative) so I
>> also had to rework it.
>>
>> Roland.
>>