RFR: 8217745: ZGC: Simplify ZLoadBarrierStubC1

[Per Liden]

Thanks Nils!

/Per

On 01/28/2019 10:29 AM, Nils Eliasson wrote:
> Looks good,
> 
> // Nils
> 
> On 2019-01-28 09:54, Per Liden wrote:
>> We can simplify ZLoadBarrierStubC1 a little bit since we know that 
>> _ref_addr is always a LIR_Address and never a Register. In the 
>> ZLoadBarrierStubC1 constructor we can just assert that this is always 
>> true. Later, when emitting code, we can just use the presence of the 
>> tmp register as indicator that we need to load the effective address.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8217745
>> Webrev: http://cr.openjdk.java.net/~pliden/8217745/webrev.0
>>
>> /Per