A shortcut for a common case is broken in GraphKit::basic_plus_adr():

src/hotspot/share/opto/graphKit.cpp:
Node* GraphKit::basic_plus_adr(Node* base, Node* ptr, Node* offset) {
  // short-circuit a common case
  if (offset == intcon(0)) return ptr;
  return _gvn.transform( new AddPNode(base, ptr, offset) );
}

On 64-bit systems offset is a long and not an int.