[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:  normal             |               Milestone:
      Component:  Compiler           |                 Version:  7.9
       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:
-------------------------------------+-------------------------------------
 Compiling hackage:half-0.2 results in a GHC Panic:

 {{{
 $ ghc --version && ghc --print-project-git-commit-id
 The Glorious Glasgow Haskell Compilation System, version 7.9.20141202
 bf2d75417b5be7e8a79a26ee57a81e00682dabd4

 $ cabal get half-0.2 && cd half-0.2/src/Numeric/
 Unpacking to half-0.2/

 $ ghc -Wall -O -fforce-recomp -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: 125160

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

 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9857>
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