MAYBE
LCTRS
  Theories
    Core, Ints
  Sorts
    Unit
  Signature
    fastfib: Int -> Unit
    p: (Int, Int, Int, Int, Int) -> Unit
    return: Int -> Unit
    u: (Int, Int, Int, Int, Int) -> Unit
    v: (Int, Int, Int, Int, Int) -> Unit
    w: (Int, Int, Int, Int, Int) -> Unit
  Rules
    p(!n, !x, !y, !z, !i) -> return(!x) [not(<(!i, !n))]
    p(!n, !x, !y, !z, !i) -> p(!n, +(!x, !y), !x, !x, +(!i, 1)) [<(!i, !n)]
    w(!n, !x, !y, !z, !i) -> p(!n, !x, !y, !z, 1) [not(>(!n, 46))]
    w(!n, !x, !y, !z, !i) -> return(-1) [>(!n, 46)]
    v(!n, !x, !y, !z, !i) -> return(!n) [not(<(!n, 0))]
    v(!n, !x, !y, !z, !i) -> return(0) [<(!n, 0)]
    u(!n, !x, !y, !z, !i) -> w(!n, !x, !y, !z, !i) [not(<=(!n, 1))]
    u(!n, !x, !y, !z, !i) -> v(!n, !x, !y, !z, !i) [<=(!n, 1)]
    fastfib(!n) -> u(!n, 1, 0, !rnd3, !rnd4)
No termination info given.

Elapsed Time:  46.35 ms