When is the difference between quotRem and divMod useful?

Question

From the haskell report:

The quot, rem, div, and mod class methods satisfy these laws if y is non-zero:

(x `quot` y)*y + (x `rem`          


        

Answer 1

This is not exactly an answer to your question, but in GHC on x86, quotRem on Int will compile down to a single machine instruction, whereas divMod does quite a bit more work. So if you are in a speed-critical section and working on positive numbers only, quotRem is the way to go.