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

[Vladimir Kozlov]

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

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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.

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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.
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