[GHC] #7902: Add support for byte endianness swapping exposed as a primops

[GHC]

#7902: Add support for byte endianness swapping exposed as a primops
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    Reporter:  tab               |       Owner:                  
        Type:  feature request   |      Status:  patch           
    Priority:  normal            |   Milestone:                  
   Component:  Compiler          |     Version:  7.7             
    Keywords:  bswap endianness  |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown    
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  
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Comment(by tab):

 I've refreshed the compiler bits to also expose a generic bSwap# that
 works on Word, and made some documentation precision on what the primops
 do for bSwap16 and bSwap32 as currently it will zero all the upper bits of
 word#.

 I've added the bits patch here for reference, and it doesn't looks as bad
 as i imagined. that's what i'll sent to the list ASAP.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7902#comment:10>
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