[GHC] #14951: SpecContsr needs two runs when one should suffice

[GHC]

#14951: SpecContsr needs two runs when one should suffice
-------------------------------------+-------------------------------------
        Reporter:  nomeata           |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:  SpecConstr
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #14844            |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by sgraf):

 That sounds like you want to associate 'argument occurence signatures'
 with functions, analogous to demand signatures, that transport `ArgOcc`
 information to arguments of a call.

 I think that would be a great idea, especially if it would work reliably
 for recursive functions. Although that will probably run into the same
 limitations as Let Up (usage from body decides over what to specialise
 for) vs. Let Down (signature needed where the function is in scope).

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14951#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler