src/share/vm/opto/library_call.cpp

*** 2192,2204 ****
       // reference stores need a store barrier.
      // (They don't if CAS fails, but it isn't worth checking.)
      pre_barrier(control(), base, adr, alias_idx, newval, value_type, T_OBJECT);
  #ifdef _LP64
      if (adr->bottom_type()->is_ptr_to_narrowoop()) {
        cas = _gvn.transform(new (C, 5) CompareAndSwapNNode(control(), mem, adr,
!                                                            EncodePNode::encode(&_gvn, newval),
!                                                            EncodePNode::encode(&_gvn, oldval)));
      } else
  #endif
        {
          cas = _gvn.transform(new (C, 5) CompareAndSwapPNode(control(), mem, adr, newval, oldval));
        }
--- 2192,2205 ----
       // reference stores need a store barrier.
      // (They don't if CAS fails, but it isn't worth checking.)
      pre_barrier(control(), base, adr, alias_idx, newval, value_type, T_OBJECT);
  #ifdef _LP64
      if (adr->bottom_type()->is_ptr_to_narrowoop()) {
+       Node *newval_enc = _gvn.transform(new (C, 2) EncodePNode(newval, newval->bottom_type()->make_narrowoop()));
+       Node *oldval_enc = _gvn.transform(new (C, 2) EncodePNode(oldval, oldval->bottom_type()->make_narrowoop()));
        cas = _gvn.transform(new (C, 5) CompareAndSwapNNode(control(), mem, adr,
!                                                           newval_enc, oldval_enc));
      } else
  #endif
      {
        cas = _gvn.transform(new (C, 5) CompareAndSwapPNode(control(), mem, adr, newval, oldval));
      }