Fib-core-O2.hs

-- $ ghc -ddump-simpl -dsuppress-all Fib.hs -fforce-recomp -O2
[1 of 1] Compiling Fib              ( Fib.hs, Fib.o )

==================== Tidy Core ====================
Result size of Tidy Core = {terms: 52, types: 59, coercions: 0}

fibs3
fibs3 = __integer 1

fibs4
fibs4 = __integer 0

fail_rPQ
fail_rPQ = \ _ -> patError "Fib.hs:4:5-39|function next"#

lvl_rPR
lvl_rPR = fail_rPQ void#

Rec {
$wnext_rPS
$wnext_rPS =
  \ w_sP2 ->
    case w_sP2 of _ {
      [] -> case lvl_rPR of wild1_00 { };
      : a_arO t_arP ->
        case t_arP of wild1_Xp {
          [] -> case lvl_rPR of wild2_00 { };
          : b_arQ ds_dOi ->
            (# plusInteger a_arO b_arQ,
               case $wnext_rPS wild1_Xp of _ { (# ww1_sP7, ww2_sP8 #) ->
               : ww1_sP7 ww2_sP8
               } #)
        }
    }
end Rec }

Rec {
fibs1
fibs1 = : fibs3 fibs2

fibs
fibs = : fibs4 fibs1

fibs2
fibs2 =
  case $wnext_rPS fibs of _ { (# ww1_sP7, ww2_sP8 #) ->
  : ww1_sP7 ww2_sP8
  }
end Rec }

Fib-core.hs

-- $ ghc -ddump-simpl -dsuppress-all Fib.hs -fforce-recomp
[1 of 1] Compiling Fib              ( Fib.hs, Fib.o )

==================== Tidy Core ====================
Result size of Tidy Core = {terms: 47, types: 47, coercions: 0}

a_rL7
a_rL7 = __integer 1

a1_rM3
a1_rM3 = __integer 0

next_rM4
next_rM4 =
  \ @ a4_aLj $dNum_aLk eta_B1 ->
    letrec {
      next1_aIB
      next1_aIB =
        \ ds_dLJ ->
          let {
            fail_dLL
            fail_dLL = \ _ -> patError "Fib.hs:4:5-39|function next"# } in
          case ds_dLJ of _ {
            [] -> fail_dLL void#;
            : a5_apx t_apy ->
              case t_apy of wild1_Xp {
                [] -> fail_dLL void#;
                : b_apz ds1_dLK ->
                  : (+ $dNum_aLk a5_apx b_apz) (next1_aIB wild1_Xp)
              }
          }; } in
    next1_aIB eta_B1

Rec {
a2_rM5
a2_rM5 = : a_rL7 a3_rM6

fibs
fibs = : a1_rM3 a2_rM5

a3_rM6
a3_rM6 = next_rM4 $fNumInteger fibs
end Rec }

Fib.hs

module Fib where
fibs = 0 : 1 : next fibs
  where
    next (a : t@(b:_)) = (a+b) : next t

Fib2-core-O2.hs

-- $ ghc -ddump-simpl -dsuppress-all Fib2.hs -fforce-recomp -O2
[1 of 1] Compiling Fib              ( Fib2.hs, Fib2.o )

==================== Tidy Core ====================
Result size of Tidy Core = {terms: 52, types: 59, coercions: 0}

fibonacci3
fibonacci3 = __integer 1

fibonacci4
fibonacci4 = __integer 0

fail_rPO
fail_rPO = \ _ -> patError "Fib2.hs:4:5-43|function next"#

lvl_rPP
lvl_rPP = fail_rPO void#

Rec {
$wnext_rPQ
$wnext_rPQ =
  \ w_sP0 ->
    case w_sP0 of _ {
      [] -> case lvl_rPP of wild1_00 { };
      : a_arO ds_dOj ->
        case ds_dOj of wild1_Xp {
          [] -> case lvl_rPP of wild2_00 { };
          : b_arP rest_arX ->
            (# plusInteger a_arO b_arP,
               case $wnext_rPQ wild1_Xp of _ { (# ww1_sP5, ww2_sP6 #) ->
               : ww1_sP5 ww2_sP6
               } #)
        }
    }
end Rec }

Rec {
fibonacci1
fibonacci1 = : fibonacci3 fibonacci2

fibonacci
fibonacci = : fibonacci4 fibonacci1

fibonacci2
fibonacci2 =
  case $wnext_rPQ fibonacci of _ { (# ww1_sP5, ww2_sP6 #) ->
  : ww1_sP5 ww2_sP6
  }
end Rec }

Fib2-core.hs

-- $ ghc -ddump-simpl -dsuppress-all Fib2.hs -fforce-recomp
[1 of 1] Compiling Fib              ( Fib2.hs, Fib2.o )

==================== Tidy Core ====================
Result size of Tidy Core = {terms: 49, types: 48, coercions: 0}

a_rL8
a_rL8 = __integer 1

a1_rM4
a1_rM4 = __integer 0

next_rM5
next_rM5 =
  \ @ a4_aLk $dNum_aLl eta_B1 ->
    letrec {
      next1_aIB
      next1_aIB =
        \ ds_dLK ->
          let {
            fail_dLM
            fail_dLM = \ _ -> patError "Fib2.hs:4:5-43|function next"# } in
          case ds_dLK of _ {
            [] -> fail_dLM void#;
            : a5_apx ds1_dLL ->
              case ds1_dLL of _ {
                [] -> fail_dLM void#;
                : b_apy rest_apG ->
                  : (+ $dNum_aLl a5_apx b_apy) (next1_aIB (: b_apy rest_apG))
              }
          }; } in
    next1_aIB eta_B1

Rec {
a2_rM6
a2_rM6 = : a_rL8 a3_rM7

fibonacci
fibonacci = : a1_rM4 a2_rM6

a3_rM7
a3_rM7 = next_rM5 $fNumInteger fibonacci
end Rec }

Fib2.hs

module Fib where
fibonacci = 0 : 1 : next fibonacci
  where
    next (a:b:rest) = (a+b) : next (b:rest)