dwarf2 call frame related question

[Dhananjay R. Deshpande]

Hi

I am trying to generate stack frame information for h8300-elf. 
For H8/300, it is not possible to add/ subtract large constant ( only 1 and 2 ) so the stack pointer adjustment by 
frame size is done by moving a constant to a register and then add/subtract register to/from stack pointer. 
	
	mov # -12, r3
	add r3, r7

If this instruction ( add r3, r7 ) is marked RTX_FRAME_RELATED_P, the following code from 
dwarf2out_frame_debug_expr()  in dwarf2out.c aborts.

        case PLUS:
        case MINUS:
        case LO_SUM:
          if (dest == stack_pointer_rtx)
            {
              /* Rule 2 */
              /* Adjusting SP.  */
              switch (GET_CODE (XEXP (src, 1)))
                {
                case CONST_INT:
                  offset = INTVAL (XEXP (src, 1));
                  break;
                case REG:
                  if ((unsigned) REGNO (XEXP (src, 1)) != cfa_temp.reg)
                    abort ();

It appears that this code does not support adjusting of stack pointer by temporary register. 
Any help on this is appreciated.

Regards,
Dhananjay