--- a/src/hotspot/share/gc/shared/threadLocalAllocBuffer.hpp	Thu Jun 28 09:06:54 2018 +0200
+++ b/src/hotspot/share/gc/shared/threadLocalAllocBuffer.hpp	Thu Jun 28 09:15:53 2018 +0200
@@ -89,8 +89,6 @@
 
   size_t remaining();
 
-  bool is_last_allocation(HeapWord* obj, size_t size) { return pointer_delta(top(), obj) == size; }
-
   // Make parsable and release it.
   void reset();
 
@@ -143,9 +141,6 @@
   inline HeapWord* allocate(size_t size);
   HeapWord* allocate_sampled_object(size_t size);
 
-  // Undo last allocation.
-  inline bool undo_allocate(HeapWord* obj, size_t size);
-
   // Reserve space at the end of TLAB
   static size_t end_reserve() {
     int reserve_size = typeArrayOopDesc::header_size(T_INT);

--- a/src/hotspot/share/gc/shared/threadLocalAllocBuffer.inline.hpp	Thu Jun 28 09:06:54 2018 +0200
+++ b/src/hotspot/share/gc/shared/threadLocalAllocBuffer.inline.hpp	Thu Jun 28 09:15:53 2018 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2018, 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
@@ -53,19 +53,6 @@
   return NULL;
 }
 
-inline bool ThreadLocalAllocBuffer::undo_allocate(HeapWord* obj, size_t size) {
-  invariants();
-
-  if (!is_last_allocation(obj, size)) {
-    return false;
-  }
-
-  set_top(obj);
-
-  invariants();
-  return true;
-}
-
 inline size_t ThreadLocalAllocBuffer::compute_size(size_t obj_size) {
   // Compute the size for the new TLAB.
   // The "last" tlab may be smaller to reduce fragmentation.