[GHC] #1600: Optimisation: CPR the results of IO

[GHC]

#1600: Optimisation: CPR the results of IO
-------------------------------------+-------------------------------------
        Reporter:  simonmar          |                Owner:
            Type:  task              |               Status:  new
        Priority:  lowest            |            Milestone:
       Component:  Compiler          |              Version:  6.6.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #8598             |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by akio):

 I've rebased the [https://github.com/takano-akio/ghc/commits/nested-cpr
 branch] on top of the join points work. In nofib, allocations are
 generally down but the difference is not very big:

 {{{
 --------------------------------------------------------------------------------
         Program           Size    Allocs   Runtime   Elapsed  TotalMem
 --------------------------------------------------------------------------------
            bspt          +0.0%     +0.1%     0.007     0.007      0.0%
       compress2          +1.5%     -0.9%     0.158     0.158     -3.7%
           fluid          +1.6%     -0.2%     0.007     0.007      0.0%
           infer          +0.0%     -1.2%     0.039     0.039      0.0%
             pic          +0.1%     -0.6%     0.005     0.005      0.0%
           solid          +0.0%     -6.6%     0.159     0.159      0.0%
 --------------------------------------------------------------------------------
             Min          -0.0%     -6.6%    -28.7%    -28.8%     -3.7%
             Max          +1.6%     +0.1%     +4.3%     +4.3%     +6.7%
  Geometric Mean          +0.1%     -0.1%    -14.7%    -14.5%     +0.0%
 }}}

 I'll look more carefully to see why the improvement is so small. I may
 have messed up something while rebasing.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1600#comment:58>
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