[GHC] #10664: T8131 times out on master

[GHC]

#10664: T8131 times out on master
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        Reporter:  bgamari           |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Compiler          |                 Version:  7.11
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by bgamari):

 Hmm, it seems like some knot-typing in `FCode` may be going wrong. I've
 been chasing this down with the profiler and `-xc` and it appears that
 we're getting stuck in `StgCmmMonad.fixC`. It appears that the only user
 of this is `StgCmmExtCode.loopDecls`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10664#comment:5>
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