patch applied (ghc): optimisation: shortcut branches when possible (x86/x86_64 only for now)

[Simon Marlow]

Mon Jan 22 03:42:01 PST 2007  mrchebas at gmail.com
  * optimisation: shortcut branches when possible (x86/x86_64 only for now)
  This is only turned on with -O, and probably won't make much
  difference at the moment, but it will be important for semi-tagging.

    M ./compiler/cmm/CLabel.hs -1 +5
    M ./compiler/cmm/Cmm.hs +36
    M ./compiler/nativeGen/AsmCodeGen.lhs -44 +89
    M ./compiler/nativeGen/MachInstrs.hs +1
    M ./compiler/nativeGen/PprMach.hs +2
    M ./compiler/nativeGen/RegAllocInfo.hs -1 +45