YES
LCTRS
  Theories
    Core, Ints
  Sorts
    Unit
  Signature
    badfib: Int -> Unit
    return: Int -> Unit
    w2: (Unit, Unit) -> Unit
  Rules
    badfib(?16) -> return(1) [or(<=(?16, 0), ?16 = 1)]
    badfib(?17) -> w2(badfib(-(?17, 1)), badfib(-(?17, 2))) [>(?17, 1)]
    w2(return(?18), return(?19)) -> return(+(?18, ?19))
Confluent by Orthogonality with proof:
  no critical pairs

Elapsed Time:  41.47 ms