re PR target/50447 ([avr] Better support of AND, OR, XOR and PLUS with constant integers for 16- and 32-bit values)

	PR target/50447
	* config/avr/avr.md (cc): New alternative out_plus_noclobber.
	(adjust_len): Ditto.
	(addhi3): Don't pipe through short; use gen_int_mode instead.
	Prior to reload, expand to gen_addhi3_clobber.
	(*addhi3): Use avr_out_plus_noclobber if applicable, use
	out_plus_noclobber in cc and adjust_len attribute.
	(addhi3_clobber): 2 new RTL peepholes.
	(addhi3_clobber): New insn.
	* config/avr/avr-protos.h: (avr_out_plus_noclobber): New prototype.
	* config/avr/avr.c (avr_out_plus_noclobber): New function.
	(notice_update_cc): Handle CC_OUT_PLUS_NOCLOBBER.
	(avr_out_plus_1): Tweak if only MSB is +/-1 and other bytes are 0.
	Set cc0 to set_zn for adiw on 16-bit values.
	(adjust_insn_length): Handle ADJUST_LEN_OUT_PLUS_NOCLOBBER.
	(expand_epilogue): No need to add 0 to frame_pointer_rtx.

From-SVN: r180193