[Shootout-list] ackermann, fibonacci and takfp benchmarks

[Einar Karttunen]

"Daniel South" <WildCard_25@HotMail.Com> writes:
> Not really, generally, allocating a new stack frame is more expensive 
> than a comparison. The difference will be that global scope variables 
> will be changed on every call and *then* compared to, making it harder 
> to for the compiler to optimise out the recursion ie. it rely has to 
> recurse and not just use a cached value. This will of course impact the 
> languages that had been optimising out the recursions, but the whole 
> point is to test the cost of calling the function, not to test how well 
> the compiler optimises. Tail recursion optimisation should not be 
> affected, just the caching.

The problem is that not all languages have cheap mutable variables.

> As a side note: in what languages would a register comparison be more 
> expensive than stack frame allocation?

foo += 1

will become modifyIORef foo (\v -> v `seq` v+1) in Haskell.
This calls an external function (in C--) of ~40 lines,
which applies the anonymous function to update the current 
value of the ioref.

- Einar Karttunen