RFR: 8215547: ZGC: Fix incorrect match rule for loadBarrierWeakSlowRegNoVec

[Per Liden]

Thanks for reviewing, Erik and Nils!

/Per

On 12/20/18 10:25 AM, Nils Eliasson wrote:
> Looks good!
> 
> // Nils
> 
> On 2018-12-19 12:51, Per Liden wrote:
>> Nils, Erik and I discussed this further off-line and found a few other 
>> inconsistencies and potential bugs. Here's an updated webrev 
>> reflecting that:
>>
>> http://cr.openjdk.java.net/~pliden/8215547/webrev.1
>>
>> This patch has passed tier1-6 and 10+ iterations in gc-test-suite.
>>
>> /Per
>>
>> On 12/18/18 10:45 AM, Per Liden wrote:
>>> The AD matching for loadBarrierWeakSlowRegNoVec is incorrect. It 
>>> should match against a LoadBarrierWeakSlowReg, not LoadBarrierSlowReg.
>>>
>>> Also the format lines for loadBarrier*SlowRegXmmAndYmm are missing 
>>> the "AndYmm" part.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8215547
>>> Webrev: http://cr.openjdk.java.net/~pliden/8215547/webrev.0
>>>
>>> /Per