Unpack primitive types by default in data

[Johan Tibell]

On Tue, Feb 28, 2012 at 1:11 AM, Simon Marlow <marlowsd at gmail.com> wrote:
> I think there are some in GHC - I've been surprised occasionally when adding
> an UNPACK makes things worse.

I just realized that there is a failure mode I didn't quite consider:
having a mix of strict and non-strict primitive fields. While this can
happen on purpose, I think it happens more often due to non-strict
being the default. Having a field with such a mix might lead to more
re-boxing.

Cheers,
  Johan