* config/pdp11/pdp11-protos.h (pdp11_initial_elimination_offset,
pdp11_regno_reg_class): New functions.
* config/pdp11/pdp11.md (define_constants): Add register numbers.
* config/pdp11/pdp11.c (pdp11_regno_reg_class,
pdp11_sp_frame_offset, pdp11_initial_elimination_offset): New
functions. 
* config/pdp11/pdp11.h (FIXED_REGISTERS, CALL_USED_REGISTERS): Add
frame pointer and argument pointer pseudo-registers.
(ARG_POINTER_REGNUM): Define.
(REG_CLASS_CONTENTS, REGNO_REG_CLASS): Add frame pointer and
argument pointer. 
(FIRST_PARM_OFFSET): Update for argument pointer.
(INITIAL_FRAME_POINTER_OFFSET): Delete.
(ELIMINABLE_REGS, INITIAL_ELIMINATION_OFFSET): New macros.
(REGNO_OK_FOR_BASE_P, REGNO_OK_FOR_INDEX_P, REGISTER_NAMES): Add
frame pointer and argument pointer.

From-SVN: r166978