[GHC] #9583: Simplifier ticks exhausted while compiling Cabal HEAD

[GHC]

#9583: Simplifier ticks exhausted while compiling Cabal HEAD
-------------------------------------+-------------------------------------
       Reporter:  ezyang             |                   Owner:
           Type:  bug                |                  Status:  new
       Priority:  highest            |               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:
-------------------------------------+-------------------------------------
 Steps to reproduce:

 1. Clone Cabal HEAD
 2. `cabal configure --with-ghc=/path/to/ghc-head`
 3. `dist/setup/setup build`

 Actual results:

 {{{
 [ 8 of 78] Compiling Distribution.Text ( Distribution/Text.hs,
 dist/build/Distribution/Text.o )
 [ 9 of 78] Compiling Distribution.Version ( Distribution/Version.hs,
 dist/build/Distribution/Version.o )
 ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 7.9.20140911 for x86_64-unknown-linux):
         Simplifier ticks exhausted
     When trying UnfoldingDone GHC.Word.$fNumWord8_$c+
     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: 813720

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

 }}}

 I know that it still fails with tick factor 4096; I haven't found a tick
 amount which makes it succeed.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9583>
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