[GHC] #1168: Optimisation sometimes decreases sharing in IO code

[GHC]

#1168: Optimisation sometimes decreases sharing in IO code
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 Reporter:  simonmar                 |          Owner:         
     Type:  bug                      |         Status:  new    
 Priority:  normal                   |      Milestone:  _|_    
Component:  Compiler                 |        Version:  6.6    
 Severity:  normal                   |     Resolution:         
 Keywords:                           |     Difficulty:  Unknown
 Testcase:  nofib/spectral/calendar  |   Architecture:  Unknown
       Os:  Unknown                  |  
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Comment (by ChrisKuklewicz):

 This just came up on the mailing list again.  The program was slow unless
 (-fno-state-hack) was used.

 Is it possible to have GHC emit a warning (as part of -Wall) to let the
 use know that GHC is applying a potentially risky simplification?

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1168#comment:4>
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