[GHC] #3437: Optimizer creates space leak on simple code

[GHC]

#3437: Optimizer creates space leak on simple code
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    Reporter:  lilac           |        Owner:         
        Type:  bug             |       Status:  new    
    Priority:  normal          |    Milestone:         
   Component:  Compiler        |      Version:  6.10.3 
    Severity:  normal          |   Resolution:         
    Keywords:                  |   Difficulty:  Unknown
    Testcase:                  |           Os:  Linux  
Architecture:  x86_64 (amd64)  |  
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Changes (by simonpj):

  * difficulty:  => Unknown

Comment:

 Excellent bug thank you!  It turns out that `go` is strict, but we don't
 do strictness analysis following `SpecConstr` so the specialised version
 of `go` is not (marked) strict.  As a result, the latter builds a thunk
 each time around the loop, which creates the leak.

 It's not hard to transfer strictness; I'll try that.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3437#comment:1>
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