[GHC] #10414: Buggy behavior with threaded runtime (-N1 working, -N2 getting into <<loop>>)

[GHC]

#10414: Buggy behavior with threaded runtime (-N1 working, -N2 getting into
<<loop>>)
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        Reporter:  exio4             |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by michaelt):

 I reduced this a little further so that it just uses the Monad instance
 and the two basic combinators:

 {{{#!hs
 rparWith s a = Eval $ \s0 -> spark# r s0
   where r = case s a of  Eval f -> case f realWorld# of  (# _, a' #) -> a'

 runEval :: Eval a -> a
 runEval (Eval x) = case x realWorld# of (# _, a #) -> a
 }}}

 and a non-recursive but monotonously layered concrete function.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10414#comment:13>
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