[GHC] #9233: Compiler performance regression

[GHC]

#9233: Compiler performance regression
-------------------------------------+-------------------------------------
              Reporter:  augustss    |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  low         |         Milestone:
             Component:  Compiler    |           Version:  7.8.2
            Resolution:              |          Keywords:
Differential Revisions:  Phab:D73    |  Operating System:  Windows
          Architecture:              |   Type of failure:  None/Unknown
  Unknown/Multiple                   |         Test Case:
            Difficulty:  Unknown     |          Blocking:
            Blocked By:              |
       Related Tickets:              |
-------------------------------------+-------------------------------------

Comment (by goldfire):

 Success. The two commits above apply different optimizations to different
 coercion functions, vastly speeding up the test case. If I increase the
 size of `X` to include 200 fields, profiling tells me that coercion-
 oriented functions take about 6% of the ~3 second (MUT) running time.
 Before these optimizations, the coercion functions were taking up ~98% of
 the running time, so this is an improvement. :)

 Before closing the ticket, would someone else like to test the work and
 confirm that the speedup is enough to close the issue? Lennart, how does
 this affect your compilation times? I wouldn't be surprised if these
 commits make a sizable difference: each commit removed potentially-
 exponential behavior.

 In any case, I'm stopping work on this for now. Let me know if I need to
 resume somewhere.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9233#comment:18>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler