[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 nomeata):

 If I understand this correctly, then you are proposing that loopification
 should tell !SpecConstr to very aggressively specialize a loopified
 binding, independent of whether its arguments are actually scrutinzed
 anywhere? But isn’t that strictly less precise than my proposal, which
 only specializes `foo` if there is some indication that it will be
 beneficial?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14951#comment:13>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler