code: private void checkTrimDupStore() {
          if ((stack.getStackDepth() >= 2) && (getPrevOpcode(1) == Const.DUP)) {
              OpcodeStack.Item item = stack.getStackItem(0);
              SPPUserValue uv = (SPPUserValue) item.getUserValue();
              if ((uv == null) || (uv.getMethod() != SPPMethod.TRIM)) {
                  return;
              }
  
              item = stack.getStackItem(1);
              uv = (SPPUserValue) item.getUserValue();
              if ((uv == null) || (uv.getMethod() != SPPMethod.TRIM)) {
                  return;
              }
  
              item.setUserValue(null);
          }
      }
docs: determines whether this operation is storing the result of a trim() call, where the trimmed string was duplicated on the stack. If it was, it clears any
  trim uservalue that was left behind in the dupped stack object