--- old/src/cpu/x86/vm/jniFastGetField_x86_64.cpp	2019-04-11 21:28:16.191967637 +0000
+++ new/src/cpu/x86/vm/jniFastGetField_x86_64.cpp	2019-04-11 21:28:16.081966937 +0000
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -76,13 +76,16 @@
   __ jcc (Assembler::notZero, slow);
   if (os::is_MP()) {
     __ xorptr(robj, rcounter);
-    __ xorptr(robj, rcounter);                   // obj, since
+    __ xorptr(robj, rcounter);                  // obj, since
                                                 // robj ^ rcounter ^ rcounter == robj
                                                 // robj is data dependent on rcounter.
   }
-  __ movptr(robj, Address(robj, 0));             // *obj
+
+  __ clear_jweak_tag(robj);
+
+  __ movptr(robj, Address(robj, 0));            // *obj
   __ mov   (roffset, c_rarg2);
-  __ shrptr(roffset, 2);                         // offset
+  __ shrptr(roffset, 2);                        // offset
 
   assert(count < LIST_CAPACITY, "LIST_CAPACITY too small");
   speculative_load_pclist[count] = __ pc();
@@ -174,13 +177,16 @@
   __ jcc (Assembler::notZero, slow);
   if (os::is_MP()) {
     __ xorptr(robj, rcounter);
-    __ xorptr(robj, rcounter);                   // obj, since
+    __ xorptr(robj, rcounter);                  // obj, since
                                                 // robj ^ rcounter ^ rcounter == robj
                                                 // robj is data dependent on rcounter.
   }
-  __ movptr(robj, Address(robj, 0));             // *obj
+
+  __ clear_jweak_tag(robj);
+
+  __ movptr(robj, Address(robj, 0));            // *obj
   __ mov   (roffset, c_rarg2);
-  __ shrptr(roffset, 2);                         // offset
+  __ shrptr(roffset, 2);                        // offset
 
   assert(count < LIST_CAPACITY, "LIST_CAPACITY too small");
   speculative_load_pclist[count] = __ pc();