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

[GHC]

#7902: Add support for byte endianness swapping exposed as a primops
-----------------------------+----------------------------------------------
Reporter:  tab               |          Owner:                  
    Type:  feature request   |         Status:  new             
Priority:  normal            |      Component:  Compiler        
 Version:  7.7               |       Keywords:  bswap endianness
      Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
 Failure:  None/Unknown      |      Blockedby:                  
Blocking:                    |        Related:                  
-----------------------------+----------------------------------------------

Comment(by tab):

 At this stage this is for RFC, i've quite possibly missed something at any
 level. Also I didn't want to refactor the llvm codegen popcnt function to
 support bswap as this might look more scary in the patch diff, but i'll
 respin the patch if everyone is happy with the direction and such.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7902#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler