Lennart Augustsson said:
Many architectures gives both the quotient and remainder when you use the division instruction, so divMod (quotRem) shouldn't cost more than a div or mod. But if the code generator takes advantage of that is another matter.
You're quite right. Bulat Ziganshin said:
qoutRem# is primitive operation in GHC
I can see quotRemInteger# and divModInteger#, as well as quotInt#, remInt#, divInt# and modInt#, but not quotRemInt# nor divModInt#. For example: $ ghc --show-iface Num.hi divModInt :: GHC.Base.Int -> GHC.Base.Int -> (GHC.Base.Int, GHC.Base.Int) {- Arity: 2 HasNoCafRefs Strictness: U(L)U(L)m Unfolding: (\ x :: GHC.Base.Int y :: GHC.Base.Int -> case @ (GHC.Base.Int, GHC.Base.Int) x of wild { I# ds -> case @ (GHC.Base.Int, GHC.Base.Int) y of wild1 { I# ds1 -> (GHC.Base.I# (GHC.Base.divInt#{1} ds ds1), GHC.Base.I# (GHC.Base.modInt#{1} ds ds1)) } }) -}