[GHC] #12506: Compile time regression in GHC 8.

[GHC]

#12506: Compile time regression in GHC 8.
-------------------------------------+-------------------------------------
        Reporter:  deech             |                Owner:  bgamari
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  8.0.1
      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:                    |
-------------------------------------+-------------------------------------

Comment (by tdammers):

 I can confirm that this *is* a regression; I'm seeing ~34 seconds overall
 compilation time on 7.10.3, vs. ~341 seconds on GHC HEAD.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12506#comment:27>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler