Heads-up: ReferenceCAS fails after C2 WB expansion

[Aleksey Shipilev]

The usual fails:

CONF=linux-x86_64-normal-server-fastdebug LOG=info make test images
TEST="hotspot_gc_shenandoah"

#  Internal Error
(/home/shade/trunks/shenandoah-jdk9/hotspot/src/share/vm/opto/machnode.cpp:380),
pid=22550, tid=22579
#  assert(tp->base() != Type::AnyPtr) failed: not a bare pointer

Since it is Friday night, let's turn ShenandoahWriteBarrierToIR off
until Roland has a chance to look into it next week.

$ hg diff
diff -r 978d7601df14 src/share/vm/gc/shenandoah/shenandoah_globals.hpp
-  experimental(bool, ShenandoahWriteBarrierToIR, true,
    \
+  experimental(bool, ShenandoahWriteBarrierToIR, false,
    \

Thanks,
-Aleksey