Remove accidentally duplicated code.
Renumber rcX.
Add and use move_computation(int t1, int t2, int r)
Use add_shared_computation( ) instead of new_computation_for_reg( ).
Replace share_and_clear( ) with clear_computation( ) which does cleanup.
Remove dependence of add_shared_computation( ) on new_computation_for_reg( ).
Remove new_computation_for_reg( ).
Replace a vm_relative.set_value( ) with a clear_computation( ).
Remove some asserts( ).
Replace remove_shared_computation(t,R) with clear_computation(t,R).