[GHC] #5916: runST isn't free

[GHC]

#5916: runST isn't free
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    Reporter:  tibbe             |       Owner:                  
        Type:  bug               |      Status:  new             
    Priority:  normal            |   Milestone:                  
   Component:  Compiler          |     Version:  7.4.1           
    Keywords:                    |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown    
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  
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Comment(by tibbe):

 I locally defined my own versions of `runST` and `runSTRep`, which I
 inlined in the last phase. I looked at the core and validated that in my
 particular case nothing bad had happened. This let me measure the actual
 performance difference: 7% on my particular benchmark. In addition it let
 me move back to nice, clean code.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5916#comment:7>
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