[9] RFR (XS): 8036667: "assert(adr->is_AddP() && adr->in(AddPNode::Offset)->is_Con()) failed: offset is a constant" with FoldStableValues on

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/8036667/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8036667
10 lines changed: 8 ins; 0 del; 2 mod

The assert is too strong. It doesn't take into account the case when 
constant offset comes from phi node.

The fix is to relax the assertion by skipping phi node case. I decided 
to keep it simple and avoided doing deep verification of the graph.

Also, fixed a crash w/ -XX:+TraceIterGVN (see callnode.cpp).

Testing: failing tests.

Thanks!

Best regards,
Vladimir Ivanov