[GHC] #14035: Weird performance results.

[GHC]

#14035: Weird performance results.
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        Reporter:  danilo2           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by danilo2):

 I've just shortened the example code and made the performance related
 questions simpler. I think it would be easier now debug what is going on
 under the hood.

 I would be very thankful for any information regarding this issue. We've
 been talking with many people - both in the company I'm working in as well
 as on IRC and we do not see any reason why this code behaves in this way
 and why it is so sensitive to the changes. We started to be worried a lot
 about how we can use Haskell for high-performance parts at all, if it is
 not obvious if a very simple change do not affect performance a lot. This
 situation makes the source code both very fragile to any changes and
 unmaintainable as a result. I'm writing this because I'm deeply worried
 about where these problems originate from and I would really like to solve
 them / know why they appear.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14035#comment:5>
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