code: public CondItem genCond(JCTree tree, int crtFlags) {
          if (!genCrt) return genCond(tree, false);
          int startpc = code.curCP();
          CondItem item = genCond(tree, (crtFlags & CRT_FLOW_CONTROLLER) != 0);
          code.crt.put(tree, crtFlags, startpc, code.curCP());
          return item;
      }
docs: Derived visitor method: check whether CharacterRangeTable
  should be emitted, if so, put a new entry into CRTable
  and call method to generate bytecode.
  If not, just call method to generate bytecode.
  @see    #genCond(JCTree,boolean)
  
  @param  tree     The tree to be visited.
  @param  crtFlags The CharacterRangeTable flags
  indicating type of the entry.