[GHC] #14816: Missed Called Arity opportunity?

[GHC]

#14816: Missed Called Arity opportunity?
-------------------------------------+-------------------------------------
        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by sgraf):

 Replying to [comment:8 nomeata]:
 > So – can we just include the free variables in the strictness signature
 during fixpointing and get that optimization without the code
 transformation?

 Well, actually I had expected DmdAnal to just work here. Not sure why `f`
 doesn't end up in `go`s signature, I suspected this has something to do
 with this `Lazy and unleashable free variables` hack, but I'm not so sure
 anymore. I'll investigate.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14816#comment:9>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler