[GHC] #367: Infinite loops can hang Concurrent Haskell

[GHC]

#367: Infinite loops can hang Concurrent Haskell
------------------------------------------+---------------------------------
  Reporter:  simonpj                      |          Owner:  ezyang              
      Type:  bug                          |         Status:  new                 
  Priority:  lowest                       |      Milestone:  _|_                 
 Component:  Compiler                     |        Version:  6.4.1               
Resolution:  None                         |       Keywords:  scheduler allocation
        Os:  Unknown/Multiple             |   Architecture:  Unknown/Multiple    
   Failure:  Incorrect result at runtime  |     Difficulty:  Unknown             
  Testcase:                               |      Blockedby:                      
  Blocking:                               |        Related:                      
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Comment(by ezyang):

 For reference, here is an example of a non-allocating recursive let-no-
 escape:

 {{{
 {-# LANGUAGE MagicHash #-}

 import GHC.Conc
 import GHC.Prim
 import GHC.Exts

 main = numSparks >>= \x -> f x `seq` return ()

 {-# NOINLINE f #-}
 f :: Int -> Bool
 f i@(I# j) = let fail :: Int# -> Bool
                  fail i = fail (i +# 1#)
       in if (case i of
             0 -> True
             _ -> False) then fail j else False
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/367#comment:27>
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