Re: [Caml-list] Are refs volatile?

[Pierre Chambart <pierre.chambart@ocamlpro.com>]

On 04/11/2015 15:23, Richard W.M. Jones wrote:
> On Wed, Nov 04, 2015 at 04:08:48PM +0100, Gabriel Scherer wrote:
>> I find the question hard to understand, so I may have missed a subtlety in
>> the code you have shown.
> It's very possible I don't know what I'm talking about, but
> this is my analysis:
>
>>>   List.iter (
>>>     fun task ->
>>>       if not !quit then task ();
>>>   ) tasks;
> Suppose that the optimizer can see the contents of `task', and see
> that it cannot update the quit variable.  In that case, could it
> assume that quit is a constant, and hoist the test outside the loop?
> ie. transforming the code to:
>
>   if not !quit then (
>     List.iter (
>       fun task ->
>         task ();
>     ) tasks
>   )
>
> Rich.
>
No. There is no specified semantic of ocaml, but in any reasonable
semantics of it won't be allowed.
I won't write something that could do that, and I would consider it a
bug if it happened.
-- 
Pierre Chambart