optimizing trivial functions

optimizing trivial functions

[Sean McLaughlin]

Hello,

   Will the Ocaml compiler optimize the following code to let y = ()?
I'm designing a program that will depend heavily on whether this code
is optimized in this way.

let f x1 x2 ... x100 = ()
let y = f x1 ... x100

Thanks,

Sean

Re: [Caml-list] optimizing trivial functions

[Sean McLaughlin]

To answer my own question, of course it can't do that, because the
arguments could have side effects.   I wonder if Haskell would do  
this...

Sean

f (print_int 5) ...



On Nov 21, 2006, at 6:20 PM, Sean McLaughlin wrote:

> Hello,
>
>   Will the Ocaml compiler optimize the following code to let y = ()?
> I'm designing a program that will depend heavily on whether this code
> is optimized in this way.
>
> let f x1 x2 ... x100 = ()
> let y = f x1 ... x100
>
> Thanks,
>
> Sean
>
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Re: [Caml-list] optimizing trivial functions

[Dmitry Bely]

On 11/26/06, Sean McLaughlin <seanmcl@cmu.edu> wrote:

> >   Will the Ocaml compiler optimize the following code to let y = ()?
> > I'm designing a program that will depend heavily on whether this code
> > is optimized in this way.
> >
> > let f x1 x2 ... x100 = ()
> > let y = f x1 ... x100

Yes, ocamlopt can do that.

> To answer my own question, of course it can't do that, because the
> arguments could have side effects.
>
> f (print_int 5) ...

So what? The arguments will be evaluated but the function call will be
optimized away.

I guess you are trying to implement some debugging that can be
switched off in the release version? If so, the following might be
interesting for you:

http://caml.inria.fr/pub/ml-archives/caml-list/2003/09/f2bf1cc8545d5e073638bd70d02b5056.en.html

- Dmitry Bely