extra code gen case for indexHead/Tail refering to Shape
extra code gen case for indexHead/Tail refering to Shape

Ignore-this: 19d37c2db8386a412e2b7a692dbc38f0

darcs-hash:20101208080146-dcabc-223f4c3fe94244959b7eccc37b78fadc02225cfe.gz

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