[GHC] #5550: GHC infinite loop when compiling vector

[GHC]

#5550: GHC infinite loop when compiling vector
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    Reporter:  simonpj           |       Owner:                                
        Type:  bug               |      Status:  merge                         
    Priority:  low               |   Milestone:  7.6.2                         
   Component:  Compiler          |     Version:  7.2.1                         
    Keywords:                    |          Os:  Unknown/Multiple              
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown                  
  Difficulty:  Unknown           |    Testcase:  simplCore/should_compile/T5550
   Blockedby:                    |    Blocking:                                
     Related:                    |  
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Comment(by carter):

 I hit this bug recently,

 see
  https://github.com/mokus0/random-fu/issues/13#issuecomment-20546431

 step to repro: ghc 7.6.3,  and using cabal / cabal-install head
 modify cabal settings to have "optimization: 2"  in the ~/.cabal/config
 file (so libraries are built with -O2)

 then when i try to install random-fu,  ghc gets stuck on specconstr as
 this ticket discusses

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5550#comment:31>
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