[GHC] #2328: Compiling DoCon with 6.8.3 has 3x slow-down compared with 6.8.2

[GHC]

#2328: Compiling DoCon with 6.8.3 has 3x slow-down compared with 6.8.2
------------------------------------------+---------------------------------
 Reporter:  simonpj                       |          Owner:         
     Type:  compile-time performance bug  |         Status:  new    
 Priority:  normal                        |      Milestone:  6.8.3  
Component:  Compiler                      |        Version:  6.8.2  
 Severity:  normal                        |     Resolution:         
 Keywords:                                |     Difficulty:  Unknown
 Testcase:                                |   Architecture:  Unknown
       Os:  Unknown                       |  
------------------------------------------+---------------------------------
Comment (by simonpj):

 Good catch!

 I'm not sure about reverting, though, because I think it may worsen
 runtime performance in quite ordinary programs.  I'm inclined to keep this
 one firmly on the radar, but wait see how my upcoming change to instances
 affects it.  Meanwhile, Serge may have to compile with 6.8.2, which is, I
 admit, rather unsatisfactory.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2328#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler