[GHC] #7116: Missing optimisation: strength reduction of floating-point multiplication

[GHC]

#7116: Missing optimisation: strength reduction of floating-point multiplication
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    Reporter:  simonmar          |       Owner:  pcapriotti             
        Type:  bug               |      Status:  new                    
    Priority:  normal            |   Milestone:  7.8.1                  
   Component:  Compiler          |     Version:  7.4.2                  
    Keywords:                    |          Os:  Unknown/Multiple       
Architecture:  Unknown/Multiple  |     Failure:  Runtime performance bug
  Difficulty:  Unknown           |    Testcase:                         
   Blockedby:                    |    Blocking:                         
     Related:                    |  
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Changes (by simonpj):

  * owner:  => pcapriotti


Comment:

 Paolo: yes, please commit your patch.  But could you add a comment `Note
 [Strength reduction]` that explains how it works.  In particular the "lit"
 is always `2`, and the `op` is always `(+)`; but at either `Float` or
 `Double`.  Perhapas you can name the `op` parameter `add_op`?  And `lit`
 can be `two_lit`.  But the comment as well!

 Thanks

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7116#comment:3>
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