[GHC] #5505: Program runs faster with profiling than without

[GHC]

#5505: Program runs faster with profiling than without
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  Reporter:  simonpj                  |          Owner:                  
      Type:  bug                      |         Status:  new             
  Priority:  high                     |      Milestone:  7.4.1           
 Component:  Compiler                 |        Version:  7.6.1           
Resolution:                           |       Keywords:                  
        Os:  Windows                  |   Architecture:  Unknown/Multiple
   Failure:  Runtime performance bug  |     Difficulty:                  
  Testcase:                           |      Blockedby:                  
  Blocking:                           |        Related:                  
--------------------------------------+-------------------------------------
Changes (by tomberek):

  * status:  closed => new
 * cc: tomberek@… (added)
  * resolution:  fixed =>
  * failure:  None/Unknown => Runtime performance bug
  * version:  7.0.3 => 7.6.1
  * owner:  simonmar =>
  * os:  Unknown/Multiple => Windows


Comment:

 The Main.hs program (compiled with or without -O2) processes a StateT
 monad over ST running around a circular list. When run with profiling it
 is around 35%  faster than without.

 It has slightly different GC behavior, but it doesn't look significant
 enough to cause such a large difference.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5505#comment:13>
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