* config/avr/avr-protos.h, config/avr/avr.c (unique_section,
	gas_output_limited_string, gas_output_ascii, output_movqi,
	output_movhi, out_movqi_r_mr, out_movqi_mr_r, out_movhi_r_mr,
	out_movhi_mr_r, out_movsi_r_mr, out_movsi_mr_r, output_movsisf,
	out_tstsi, out_tsthi, ret_cond_branch, ashlqi3_out, ashlhi3_out,
	ashlsi3_out, ashrqi3_out, ashrhi3_out, ashrsi3_out, lshrqi3_out,
	lshrhi3_out, lshrsi3_out, output_reload_inhi, output_reload_insisf,
	out_shift_with_cnt, ptrreg_to_str, cond_string, encode_section_info):
	Add "const" as needed to remove warnings.

	* config/avr/avr.c (avr_override_options, avr_init_once,
	function_prologue, function_epilogue, frame_pointer_required_p,
	class_likely_spilled_p, order_regs_for_local_alloc,
	avr_address_cost, avr_ret_register): Use K&R style arguments.
	(initial_elimination_offset, gas_output_limited_string):
	Remove ATTRIBUTE_UNUSED from the used arguments.
	(output_mov*, out_mov*_r_mr, out_mov*_mr_r, output_reload_insisf):
	Use local variables src, dest, base to access operands[].
	Rename reg_dest to reg_src if that's what it is.
	(output_movhi, output_movsisf): Optimize loading 8-bit immediate
	constants to LD_REGS if reg_was_0.
	(output_reload_insisf): Change arg 3 to insn length and set it.
	(out_movhi_r_mr, out_movhi_mr_r): Use in/out for more efficient
	access to 16-bit I/O register pairs.
	(avr_address_cost): Lower cost for the above case.
	(out_tsthi): Use "or" (faster) instead of "sbiw" if the operand
	may be clobbered, also for LD_REGS.
	(adjust_insn_length): Correct insn length for iorhi3 and iorsi3
	with a CONST_INT.

	* config/avr/avr.h (PTRDIFF_TYPE): Make signed.

	* config/avr/avr.md: Change all uses of the TEST_HARD_REG_CLASS
	macro to test_hard_reg_class function.
	(*movsi, *movsf): Change "cc" attribute from "clobber" to "none"
	for loading immediate constants to LD_REGS.
	(andsi3, cmphi, cmpsi): Add return statements to avoid warnings.

From-SVN: r36117