message: Add C++ no gradient for Floor operation.
diff: @@ -38,6 +38,7 @@ REGISTER_NO_GRADIENT_OP("NotEqual");
  REGISTER_NO_GRADIENT_OP("LogicalAnd");
  REGISTER_NO_GRADIENT_OP("LogicalOr");
  REGISTER_NO_GRADIENT_OP("LogicalNot");
  +REGISTER_NO_GRADIENT_OP("Floor");
  // Conjugate helper function returns the conjugate of an Output if it
  // is complex valued.
  