RFR: Add support of lzcnt and tzcnt

[Christian Thalinger]

> On Nov 17, 2014, at 1:46 PM, Igor Veresov <igor.veresov at oracle.com> wrote:
> 
> Alright, makes sense. So, I guess, I have to propagate hotspot switches like UseCount{Leading, Trailing} ZerosInstruction into AMD64 (a subclass of Architecture), right?

Correct.  Like we do with other features in com.oracle.graal.hotspot.amd64.AMD64HotSpotBackendFactory.computeFeatures(HotSpotVMConfig)

> 
> igor
> 
> 
>> On Nov 17, 2014, at 1:04 PM, Christian Wimmer <christian.wimmer at oracle.com> wrote:
>> 
>>>     "com.oracle.graal.replacements.amd64" : {
>>> -      "dependencies" : ["com.oracle.graal.replacements"],
>>> +      "dependencies" : [
>>> +          "com.oracle.graal.hotspot"
>>> +          ],
>> 
>> That adds a dependency from a VM-independent project to a HotSpot project - so while you can do that technically (as long as you do not introduce a cyclic dependency), it violates the Compiler-VM separation.
>> 
>> -Christain
>> 
>