PUBLIC

 

Hi Simon, Matt & others,

 

It took me until now to be able to try out GHC HEAD, mostly because I had to adapt to all the GHC.Unit.* refactorings. However, now I am on a466b02492f73a43c6cb9ce69491fc85234b9559 which includes the commit Simon pointed out. My original plan was to expose the first half of specProgram, i.e. the part that calls `go binds`. I did that because I want to apply specialisation on collected whole-program Core, not just whatever would be in scope for a Core-to-Core plugin pass, so I am not writing a CoreM and I don’t even have a ModGuts at hand.

 

However, I found out from Matt’s email on this thread that this is not going to be enough and eventually I’ll need to figure out how I intend to apply the rewrite rules that come out of this. So for now, I am just turning on specialization in the normal pipeline by setting Opt_Specialise, Opt_SpecialiseAggressively, and Opt_CrossModuleSpecialise. And I’m still not seeing $dm>> being specialized.

 

Is this because I define each of “class Monad”, “data IO a”, “instance Monad IO”, and “main”, in four distinct modules? In other words, is this something I will not be able to try out until I figure out how to make a fake ModGuts and run a CoreM from outside the normal compilation pipeline, feeding it the whole-program collected CoreBinds? But if so, why is it that when I feed my whole program to just specBinds (which I can try easily since it has no ModGuts/CoreM dependency other than a uniq supply and the CoreProgram), I get back an empty UsageDetails?

Thanks,

Gergo

 

For reference, the relevant definitions dumped from GHC with specialization (supposedly) turned on:

 

main = $fMonadIO_$c>> @() @() sat_sJg xmain

 

$fMonadIO_$c>> :: forall a b. IO a -> IO b -> IO b

$fMonadIO_$c>> = \ (@a_aF9) (@b_aFa) -> $dm>> @IO $fMonadIO @a_aF9 @b_aFa;

 

$dm>> :: forall (m :: Type -> Type) a b. Monad m => m a -> m b -> m b

$dm>>

  = \ (@(m_ani :: Type -> Type))

      ($dMonad_sIi [Occ=Once1] :: Monad m_ani)

      (@a_ar4)

      (@b_ar5)

      (ma_sIj [Occ=Once1] :: m_ani a_ar4)

      (mb_sIk [Occ=OnceL1] :: m_ani b_ar5) ->

      let {

        sat_sIm [Occ=Once1] :: a_ar4 -> m_ani b_ar5

        [LclId]

        sat_sIm = \ _ [Occ=Dead] -> mb_sIk } in

      >>= @m_ani $dMonad_sIi @a_ar4 @b_ar5 ma_sIj sat_sIm

 

 

PUBLIC

 

Indeed, I am using 9.0.1. I’ll try upgrading. Thanks!