#7258: Compiling DynFlags is jolly slow
    Reporter:  simonpj           |       Owner:  simonpj         
        Type:  bug               |      Status:  new             
    Priority:  normal            |   Milestone:  7.8.1           
   Component:  Compiler          |     Version:  7.6.1           
    Keywords:                    |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown    
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  

Comment(by simonpj):

 OK I have verified that the changes to the occurrence analyser (above)
 make essentially zero different to nofib numbers.  It's a very worthwhile
 simplification, because it completely gets rid of the `getProxies` stuff
 that was eating all the time before.

 Alas, compiling W2 is still non-linear.  Here's the allocation by the
 stage-2 compiler
  * 50 fields: 1.01 Gbyte
  * 100 fields: 2.98 Gbyte
  * 200 fields: 9.64 Gbyte

 This is after including the improvements to the derived `Read` code in

 So something is still wrong.  Need to do some profilling to find out.

 There are some very deeply nested lambdas, which lead to SRTs of ever-
 increasing size, so there is definitely a quadratic effect there.  But I'm
 not sure that is all.

Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7258#comment:12>
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