RFR(XS): 8150727: [JVMCI] add LoadLoad to the implicit memory barriers on AMD64

Christian Thalinger christian.thalinger at oracle.com
Fri Feb 26 19:30:08 UTC 2016


> On Feb 26, 2016, at 9:24 AM, Tom Rodriguez <tom.rodriguez at oracle.com> wrote:
> 
> It shouldn’t.  A MembarNode is still built since we have to order the memory operations.  The implicit barriers stuff just means we don’t need extra instructions to ensure the ordering beyond issuing them in the right order.

Right, it’s used in the LIRGenerator:

com.oracle.graal.lir.gen.LIRGeneratorTool.emitMembar(int)

Looks good.

> 
> tom
> 
>> On Feb 26, 2016, at 10:32 AM, Christian Thalinger <christian.thalinger at oracle.com <mailto:christian.thalinger at oracle.com>> wrote:
>> 
>> I’m assuming this doesn’t change the generated code at all.  Does it reduce the number of nodes in compiler graphs?
>> 
>>> On Feb 26, 2016, at 4:47 AM, Roland Schatz <roland.schatz at oracle.com <mailto:roland.schatz at oracle.com>> wrote:
>>> 
>>> Hi,
>>> 
>>> Please review and integrate this small fix:
>>> http://cr.openjdk.java.net/~rschatz/JDK-8150727/webrev.00/ <http://cr.openjdk.java.net/~rschatz/JDK-8150727/webrev.00/>
>>> https://bugs.openjdk.java.net/browse/JDK-8150727 <https://bugs.openjdk.java.net/browse/JDK-8150727>
>>> 
>>> It was contributed by Benoit Daloze (cc'ed), and lgtm (but I'm not a reviewer myself).
>>> 
>>> Thanks,
>>> Roland
>> 
> 

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