hg: shenandoah/jdk9/hotspot: Logic that moves a null check in the expanded barrier may cause a memory access that doesn't depend on the barrier to bypass the null check

[rwestrel at redhat.com]

Changeset: ae2cbcf798c3
Author:    roland
Date:      2016-11-19 17:55 +0100
URL:       http://hg.openjdk.java.net/shenandoah/jdk9/hotspot/rev/ae2cbcf798c3

Logic that moves a null check in the expanded barrier may cause a memory access that doesn't depend on the barrier to bypass the null check

! src/share/vm/opto/shenandoahSupport.cpp
+ test/gc/shenandoah/compiler/TestExpandedWBLostNullCheckDep.java