[GHC] #9857: GHC 7.9 panics (simplifier ticks exhausted) on `half-0.2`

[GHC]

#9857: GHC 7.9 panics (simplifier ticks exhausted) on `half-0.2`
-------------------------------------+-------------------------------------
              Reporter:  hvr         |            Owner:  simonpj
                  Type:  bug         |           Status:  new
              Priority:  high        |        Milestone:
             Component:  Compiler    |          Version:  7.9
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  Compile-    |       Blocked By:
  time crash                         |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------

Comment (by hvr):

 I've tried up to `-fsimpl-tick-factor=100000` and it still fails:

 {{{
 $ ghc -Wall -O -fforce-recomp -fsimpl-tick-factor=100000 -c Half.hs
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.9.20141202 for x86_64-unknown-linux):
         Simplifier ticks exhausted
   When trying UnfoldingDone lvl_s5yo
   To increase the limit, use -fsimpl-tick-factor=N (default 100)
   If you need to do this, let GHC HQ know, and what factor you needed
   To see detailed counts use -ddump-simpl-stats
   Total ticks: 125160000

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 }}}

 does it make sense to try even higher?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9857#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler