RFR(m): 8221734: Deoptimize with handshakes

[Robbin Ehn]

> Thumbs up!

Thanks Dan!

/Robbin

> 
> Dan
> 
>> Full:
>> http://cr.openjdk.java.net/~rehn/8221734/v5/webrev/
>>
>> Thanks, Robbin
>>
>> On 2019-04-25 14:05, Robbin Ehn wrote:
>>> Hi all, please review.
>>>
>>> Let's deopt with handshakes.
>>> Removed VM op Deoptimize, instead we handshake.
>>> Locks needs to be inflate since we are not in a safepoint.
>>>
>>> Goes on top of:
>>> https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2019-April/033491.html 
>>>
>>>
>>> Code:
>>> http://cr.openjdk.java.net/~rehn/8221734/v1/webrev/index.html
>>> Issue:
>>> https://bugs.openjdk.java.net/browse/JDK-8221734
>>>
>>> Passes t1-7 and multiple t1-5 runs.
>>>
>>> A few startup benchmark see a small speedup.
>>>
>>> Thanks, Robbin
>