Hi!
I’ve always thought that `quotRem` is faster than `quot` + `rem`, since
both `quot` and `rem` are just "wrappers" that compute both the quotient
and the remainder and then just throw one out. However, today I looked
into the implementation of `quotRem` for `Int32` and found out that it’s
not true:
quotRem x@(I32# x#) y@(I32# y#)
| y == 0 = divZeroError
| x == minBound && y == (-1) = overflowError
| otherwise = (I32# (narrow32Int# (x# `quotInt#`
y#)),
I32# (narrow32Int# (x# `remInt#`
y#)))
Why? The `DIV` instruction computes both, doesn’t it? And yet it’s being
performed twice here. Couldn’t one of the experts clarify this bit?
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