[GHC] #4801: Typechecker performance regression 6.12 -> 7.0.1

[GHC]

#4801: Typechecker performance regression 6.12 -> 7.0.1
--------------------------------------+-------------------------------------
  Reporter:  simonmar                 |          Owner:  simonpj         
      Type:  bug                      |         Status:  closed          
  Priority:  high                     |      Milestone:  7.0.2           
 Component:  Compiler (Type checker)  |        Version:  7.0.1           
Resolution:  fixed                    |       Keywords:                  
  Testcase:  perf/compiler/T4801      |      Blockedby:                  
Difficulty:                           |             Os:  Unknown/Multiple
  Blocking:                           |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown             |  
--------------------------------------+-------------------------------------
Changes (by simonpj):

  * status:  new => closed
  * testcase:  => perf/compiler/T4801
  * resolution:  => fixed


Comment:

 This (long-list) regression is certainly fixed.  The HEAD is faster than
 6.12.3. I've added a performance test to keep it that way.
 {{{
 Wed Jan 12 06:56:04 PST 2011  simonpj at microsoft.com
   * Major refactoring of the type inference engine

   This patch embodies many, many changes to the contraint solver, which
   make it simpler, more robust, and more beautiful.  But it has taken
   me ages to get right. The forcing issue was some obscure programs
   involving recursive dictionaries, but these eventually led to a
   massive refactoring sweep.
 }}}
 I'll look at #4856 separately, but am closing this one.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4801#comment:5>
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