patch applied (ghc): default ppr method for CmmGraph now tells more about the representation

[nr at eecs.harvard.edu]

Tue Sep 11 07:27:01 PDT 2007  Norman Ramsey <nr at eecs.harvard.edu>
  * default ppr method for CmmGraph now tells more about the representation
  (Previously, ppr had tried to make the zipper representation look as
  much like the ListGraph representation as possible.  This decision was
  unhelpful for debugging, so although the old code has been retained,
  the new default is to tell it like it is.  It may be possible to
  retire PprCmmZ one day, although it may be desirable to retain it as
  the internal form becomes less readable.
  

    M ./compiler/cmm/PprCmmZ.hs -10 +4
    M ./compiler/cmm/ZipCfgCmm.hs -2 +34