--- old/src/hotspot/cpu/x86/x86_64.ad	2018-08-20 11:53:32.474410976 +0100
+++ new/src/hotspot/cpu/x86/x86_64.ad	2018-08-20 11:53:32.190410130 +0100
@@ -6237,6 +6237,44 @@
   ins_pipe(pipe_slow); // XXX
 %}
 
+instruct cacheWB(indirect addr)
+%{
+  match(CacheWB addr);
+
+  ins_cost(100);
+  format %{"cache wb $addr" %}
+  ins_encode %{
+    assert($addr->index_position() < 0, "should be");
+    assert($addr$$disp == 0, "should be");
+    __ cache_wb(Address($addr$$base$$Register, 0));
+  %}
+  ins_pipe(pipe_slow); // XXX
+%}
+
+instruct cacheWBPreSync()
+%{
+  match(CacheWBPreSync);
+
+  ins_cost(100);
+  format %{"cache wb presync" %}
+  ins_encode %{
+    __ cache_wbsync(true);
+  %}
+  ins_pipe(pipe_slow); // XXX
+%}
+
+instruct cacheWBPostSync()
+%{
+  match(CacheWBPostSync);
+
+  ins_cost(100);
+  format %{"cache wb postsync" %}
+  ins_encode %{
+    __ cache_wbsync(false);
+  %}
+  ins_pipe(pipe_slow); // XXX
+%}
+
 //----------BSWAP Instructions-------------------------------------------------
 instruct bytes_reverse_int(rRegI dst) %{
   match(Set dst (ReverseBytesI dst));