[GHC] #12028: Large let bindings are 6x slower (since 6.12.x to 7.10.x)

[GHC]

#12028: Large let bindings are 6x slower (since 6.12.x to 7.10.x)
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        Reporter:  tommd             |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by bgamari):

 Interesting, it looks like we are spending a significant amount of time
 (500 ms out of a 1500 ms compilation) in CodeGen on 8.0.1 despite the fact
 that the simplified program is only 6000 terms, 2000 types.

 It looks like there was a rather significant regression from 7.6 (where
 compilation took around 700 ms) to 7.8 (1200 ms).

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12028#comment:3>
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