RFR(S): 8155241: Crash with assert in Xcomp mode and with disabled ReduceBulkZeroing

[Tobias Hartmann]

Hi,

please review the following patch:

https://bugs.openjdk.java.net/browse/JDK-8155241
http://cr.openjdk.java.net/~thartmann/8155241/webrev.00/

JDK-8076188 introduced code that eliminates an arraycopy if the destination is non escaping. The newly added LoadNode::find_previous_arraycopy() assumes that a clonebasic arraycopy that overwrites a newly allocated array always sets the corresponding InitializeNode to "complete", i.e., takes care of zeroing the array. However, this is only the case if ReduceBulkZeroing is enabled.

I fixed the assert and added a regression test.

Tested with JPRT and RBT (running).

Thanks,
Tobias