[15] RFR(S): 8248388: ZGC: Load barrier incorrectly elided in jdk/java/text/Format/DateFormat/SDFTCKZoneNamesTest.java

[Nils Eliasson]

Hi,

This issue was found on aarch64 but applies to all platforms. Stefan 
Karlsson tracked down the source of the issue and created a reproducer.

The bug is that the access API was not used in two places in macro.cpp 
where scalar replacement generate a load from the source of an 
arraycopy. This causes the creation of a LoadP without a barrier.

I fix this by reusing arraycopynode::load to create the loads. The 
abstraction is a bit of, but I don't want to make a larger change this 
late in 15.

https://bugs.openjdk.java.net/browse/JDK-8248388
http://cr.openjdk.java.net/~neliasso/8248388/webrev.01/

Please review,
Nils Eliasson