alias code -- minor nits

[Jeffrey A Law]

The updated alias code exposed two minor bugs in the old alias code --
namely that struct_value_incoming_rtx and static_chain_rtx need to
be put in the tenative base values array since they might be hard
regs with pointers at function entry.

I have the following code in init_alias_analysis to deal with them:

      if (struct_value_incoming_rtx
          && GET_CODE (struct_value_incoming_rtx) == REG)
      new_reg_base_value[REGNO (struct_value_incoming_rtx)]
        = gen_rtx (ADDRESS, Pmode, struct_value_incoming_rtx);

      if (static_chain_rtx
          && GET_CODE (static_chain_rtx) == REG)
      new_reg_base_value[REGNO (static_chain_rtx)]
        = gen_rtx (ADDRESS, Pmode, static_chain_rtx);

Jeff