This is just a code clean-up.

The bulky code from *addhi3_sp_R_pc2 and *addhi3_sp_R_pc3 is done by a small C
function that does the same (except that it prints some comment depending on
-dp or -fverbose-asm).

*movhi_sp is an insn that should not be there and go away because it is a move
insn and there should be at most one move insn per mode (HImode in this case).

stack_register_operand, i.e. (REG:HI 32), is in register class STACK_REG, thus
not in NO_REGS, thus element of register_operand, general_regs and
nonimmediate_operand which are the predicates/condition of *movhi.  *movhi
already knows to handle "q,r" and "r,q" moves, same applies to the output
function output_movhi.

The patch passes the test suite, of course.

Ok?

Moreover, I'd like to remove constraint "R" which is just used on one insn now
and replace it by 3-letter constraint C.. so that prefix R is free.

R is of absolutely no use in inline assembly and the constraint can be
renamed/removed from documentation, IMO.

Johann

	* config/avr/avr-protos.h (avr_out_addto_sp): New prototype.
	* config/avr/avr.c (avr_out_addto_sp): New function.
	(adjust_insn_length): Handle ADJUST_LEN_ADDTO_SP.
	* config/avr/avr.md (adjust_len): Add "addto_sp".
	(*movhi_sp): Remove insn.
	(*addhi3_sp_R_pc2, *addhi3_sp_R_pc3): Merge to *addhi3_sp_R.