Make class status volatile.

Discourage loads and stores from reordering around the status being updated.
Bug: 15347354

Change-Id: Ice805cb834617747c8209e98a142d3e5c7585719
diff --git a/compiler/llvm/gbc_expander.cc b/compiler/llvm/gbc_expander.cc
index 25c9b20..f8dca66 100644
--- a/compiler/llvm/gbc_expander.cc
+++ b/compiler/llvm/gbc_expander.cc
@@ -1868,6 +1868,10 @@
 
   phi->addIncoming(storage_object_addr, block_check_init);
   phi->addIncoming(loaded_storage_object_addr, block_after_load_static);
+
+  // Ensure load of status and load of value don't re-order.
+  irb_.CreateMemoryBarrier(art::kLoadLoad);
+
   return phi;
 }