[GHC] #7286: GHC doesn't optimise away primitive identity conversions

[GHC]

#7286: GHC doesn't optimise away primitive identity conversions
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    Reporter:  rl                |       Owner:  igloo                       
        Type:  bug               |      Status:  new                         
    Priority:  high              |   Milestone:  7.8.1                       
   Component:  Compiler          |     Version:  7.7                         
    Keywords:                    |          Os:  Unknown/Multiple            
Architecture:  Unknown/Multiple  |     Failure:  Compile-time performance bug
  Difficulty:  Unknown           |    Testcase:                              
   Blockedby:                    |    Blocking:                              
     Related:                    |  
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Comment(by ian@…):

 commit e3d78899ce336e8637ae231550c04f0f68bca2aa
 {{{
 Author: Ian Lynagh <ian at well-typed.com>
 Date:   Sun Oct 21 13:48:09 2012 +0100

     Add some more primop rules; fixes #7286

     As well as the rules mentioned in the ticket, I've also gone through
     and added some more rules that might be useful in other cases.

  compiler/prelude/PrelRules.lhs |   56
 ++++++++++++++++++++++++++++++++--------
  1 files changed, 45 insertions(+), 11 deletions(-)
 }}}

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7286#comment:4>
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