Turning ForceSpecConstr/NoSpecConstr into pragmas?

[Andrew Farmer]

Wouldn't #2 mean we'd have to annotate (via pragma) every type we want to
eliminate, rather than a single type?

I think the current design serves the need: "I want you to try really hard
on this function." ... which seems useful.

#2 seems like an orthogonal issue: "I want to ensure this type is optimized
away" ... which also seems useful, but I'm not sure it replaces the first
use. (Though I missed the suggestion at ICFP... is this the ephemeral types
one?)


On Wed, Oct 9, 2013 at 9:55 AM, Johan Tibell <johan.tibell at gmail.com> wrote:

> On Wed, Oct 9, 2013 at 7:13 AM, Austin Seipp <austin at well-typed.com>
> wrote:
> > Early last week I was reminded of something, which was that vector/dph
> > depend on the stage2 compiler - this is because both packages use
> > annotations to specify ForceSpecConstr and NoSpecConstr on several key
> > datatypes.
> >
> > For most of our platforms (now including ARM,) this should generally
> > be OK, because we have stage2 and the linker available to support it.
> >
> > But in particular, it makes vector and dph unusable for cross
> > compilers. This might be somewhat problematic for e.g. iOS or an RPi,
> > where we only have a stage1 cross compiler - but it's reasonable to
> > assume we may want to use vector there! And more and more libraries
> > depend on vector these days.
>
> I raised the same issue with Simon PJ a while ago. We ran into this
> problem when trying use GHC as a cross-compiler at Google. I think we
> should
>
>  1. Convert it to a pragma.
>  2. Look into a design that was suggested at ICFP, namely to put a
> pragma on the data type we want to get optimized away instead.
>
> -- Johan
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