RFR: 8238190 : [JVMCI] Fix single implementor speculation for diamond shapes.

[David Leopoldseder]

Hi,

I updated the test case with @bug and @summary as requested and ran 
hs-tier1 and hs-tier2 with latest changes again.
All green.

Please find the revised webrev under 
http://cr.openjdk.java.net/~davleopo/JDK-8238190/webrev.002/

thanks,

- david

Am 31.01.20 um 18:47 schrieb Vladimir Kozlov:
> CCing to Runtime group since it is runtime code. Coleen already looked 
> on this fix but we need official review here.
>
> David, it seems you did not pull latest fixes from JDK. Most of 
> failures in your testing should be fixed already. There are testing 
> infra "red" failures which are nothing to do with changes.
> I would suggest to pull latest changes before push (after reviews) and 
> run tier1-2 again.
>
> In short, I don't see new failures in tier1-2 testing and tier3-graal. 
> Fix looks good to me.
>
> Thanks,
> Vladimir
>
> On 1/31/20 12:49 AM, David Leopoldseder wrote:
>> Hi,
>>
>> Please review this tiny change (+ a new test case exercising the 
>> pattern) to
>> fix the single implementor logic in instanceKlass for diamond shaped 
>> class hierarchies.
>>
>> This bug was revealed in Graal where we use the single implementor 
>> logic for invokeinterface devirtualization.
>>
>> https://bugs.openjdk.java.net/browse/JDK-8238190
>> http://cr.openjdk.java.net/~davleopo/JDK-8238190/webrev.001/
>>
>> Thank you.
>>
>> - david
>>