[GHC] #7850: Strangely high memory usage on optimized Ackermann function

[GHC]

#7850: Strangely high memory usage on optimized Ackermann function
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    Reporter:  dolio             |       Owner:                         
        Type:  bug               |      Status:  new                    
    Priority:  normal            |   Milestone:                         
   Component:  Compiler          |     Version:  7.6.2                  
    Keywords:                    |          Os:  Unknown/Multiple       
Architecture:  Unknown/Multiple  |     Failure:  Runtime performance bug
  Difficulty:  Unknown           |    Testcase:                         
   Blockedby:                    |    Blocking:                         
     Related:                    |  
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Comment(by awson):

 Most interesting is that while many notice `-kc1M` cure the problem they
 still insist it runs much slower than Ocaml version. But it is *NOT*! It
 takes less than 6.5 secs to deliver a correct answer for original
 unmodified version of ack with `-kc1M` on all my configs:

 Windows 8 64-bit on Q9450 2.66MHz:[[BR]]
 ghc-7.6.2 32-bit - 6.49 secs[[BR]]
 ghc-7.6.2 64-bit - 6.47 secs

 Windows 7 on i7-2675QM[[BR]]
 ghc-7.6.2 32-bit - 6.13 secs[[BR]]
 ghc-7.6.2 64-bit - 3.80 (!!!) secs (i tried this several times with the
 same result)

 Could it be GHC RTS on Windows which makes the difference?

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7850#comment:24>
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