[GHC] #2902: Example where ghc 6.10.1 fails to optimize recursive instance function calls

[GHC]

#2902: Example where ghc 6.10.1 fails to optimize recursive instance function
calls
-----------------------------------------+----------------------------------
    Reporter:  Syzygies                  |        Owner:         
        Type:  run-time performance bug  |       Status:  new    
    Priority:  normal                    |    Milestone:         
   Component:  Compiler                  |      Version:  6.10.1 
    Severity:  normal                    |   Resolution:         
    Keywords:  class instance            |   Difficulty:  Unknown
    Testcase:                            |           Os:  MacOS X
Architecture:  x86_64 (amd64)            |  
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Changes (by simonpj):

 * cc: batterseapower at hotmail.com (added)
  * difficulty:  => Unknown

Comment:

 Ha!  Excellent example.  What is happening is that I'm generating stuff
 like
 {{{
 union d = let u2 = union d in \x. ... u2 ...
 }}}
 If only we had Max's arity analysis, this would generate good code (by
 inlining u2) but now it doesn't.  Max, this is an excellent test case.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2902#comment:1>
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