Request for reviews (M): 6674600, 6259129 (last Escape Analysis changes for HS12)

[Vladimir Kozlov]

I updated changes for 6259129.

http://webrev.invokedynamic.info/kvn/6259129/index.html

As Chuck suggested I divided eliminate_allocate_node() method
into 3 methods (he suggested 5 methods):

   bool can_eliminate_allocation()
   bool scalar_replacement()
   void process_users_of_allocation()

I used new method replace_node() only in macro.cpp file.
And I filed the rfe 6677629 to investigate a possibility to call
hash_delete() and add_users_to_worklist() from subsume_node()
to clean such calls in all C2 files.

Thanks,
Vladimir

Vladimir Kozlov wrote:
> Chuck suggested to add a new method for the next sequence
> which I used very often in macro.cpp (6259129 changes):
> I added new method into PhaseIterGVN:
> 
> 
> +  // Replace old node with new one.
> +  void replace_node( Node *old, Node *nn ) {
> +    add_users_to_worklist(old);
> +    hash_delete(old);
> +    subsume_node(old, nn);
> +  }
> +
> 
> But I am wondering why we not always put users of old node
> on worklist in subsume_node()?
> 
> Thanks,
> Vladimir
> 
> Vladimir Kozlov wrote:
>> Thank you for previous reviews.
>>
>> Here are my last EA changes for HS12.
>>
>> Note: both changesets have similar memory walking code but
>> I don't want to optimize/combine this code now. I will do it later.
>>
>> Thanks,
>> Vladimir
>>
>> ---------------------------------------------------------------------------- 
>>
>> http://webrev.invokedynamic.info/kvn/6674600/index.html
>>
>> Fixed 6674600: (Escape Analysis) Optimize memory graph for instance's 
>> fields
>>
>> Problem:
>> To reallocate a scalarized object during a deoptimization we need
>> to know the state (values) of object's non-static fields at a safepoint.
>>
>> Solution:
>> Use aggressive memory optimizations during Iterative GVN
>> to obtain values assigned to instance's non-static fields.
>>
>> ---------------------------------------------------------------------------- 
>>
>> http://webrev.invokedynamic.info/kvn/6259129/index.html
>>
>> Fixed 6259129: (Escape Analysis) scalar replacement for non-escaping 
>> objects
>>
>> Problem:
>> To reallocate a scalarized object during a deoptimization we need
>> to know the state (values) of object's non-static fields at a safepoint.
>>
>> Solution:
>> Replace non-escaping allocations with SafePointScalarObjectNode
>> for a scalar replacement during macro expansion of Allocate nodes.
>> Do an additional memory search to obtain values assigned to instance's
>> non-static fields. Disable scalar replacement if a field's value
>> can't be found.
>> ---------------------------------------------------------------------------- 
>>
>