turn off let floating

[Simon Marlow]

On 20 April 2004 12:48, Bernard James POPE wrote:

> Results:
> 
>    method          runtime (s)
>    ---------------------------
>    pure            0.7
>    ffi             3.2
>    fastMut         15
>    ioref           23

I very strongly suspect that it is the unsafePerformIO that hurts
performance in the fastMut case.  Otherwise this case would be around
the same speed as the FFI example, perhaps faster.

You could try out that theory by copying the definition of
unsafePerformIO into your code, and putting an INLINE pragma on it.  I
think it's safe to do this in your case (it's not safe in general).

Cheers,
	Simon