fix code generation for tuples as the result of a branch
fix code generation for tuples as the result of a branch

Ignore-this: c72555176c5dcc1f2ad16a2dcea13187
- do this by pushing the conditional through each tuple component, although I
  doubt nvcc is clever enough to only evaluate the conditional expression once.
- contributed by Ben Lever <Ben.Lever@nicta.com.au>

darcs-hash:20100902234324-dcabc-4517ef330aa443d328807a5acccee4d6f58e0c90.gz

robeverest/accelerate,robeverest/accelerate,wilbowma/accelerate,sjfloat/accelerate,wilbowma/accelerate,rrnewton/accelerate