patch applied (ghc): Use n-ary sums and products for NDP's generic representation

[Roman Leshchinskiy]

Wed Aug 22 23:09:45 PDT 2007  Roman Leshchinskiy <rl at cse.unsw.edu.au>
  * Use n-ary sums and products for NDP's generic representation
  
  Originally, we wanted to only use binary ones, at least initially. But this
  would a lot of fiddling with selectors when converting to/from generic
  array representations. This is both inefficient and hard to implement.
  Instead, we will limit the arity of our sums/product representation to, say,
  16 (it's 3 at the moment) and initially refuse to vectorise programs for which
  this is not sufficient. This allows us to implement everything in the library.
  Later, we can implement the necessary splitting.

    M ./compiler/prelude/PrelNames.lhs -7 +4
    M ./compiler/vectorise/VectBuiltIn.hs -28 +52
    M ./compiler/vectorise/VectMonad.hs -3 +6
    M ./compiler/vectorise/VectUtils.hs -73 +69