* config/avr/avr-protos.h (avr_hard_regno_mode_ok): New prototype.
	* config/avr/avr.c (out_adj_frame_ptr, out_set_stack_ptr):
	New functions, common code moved from function_{prologue,epilogue}
	and extended to support the -mtiny-stack option.
	(function_prologue, function_epilogue): Use them.
	Use lo8/hi8 consistently for asm output readability.
	(avr_hard_regno_mode_ok): New function.
	* config/avr/avr.h (TARGET_SWITCHES): Fix typo.  Add -mtiny-stack.
	(UNITS_PER_WORD): Define as 4 (not 1) when compiling libgcc2.c.
	(HARD_REGNO_MODE_OK): Call the avr_hard_regno_mode_ok function.
	* config/avr/avr.md (*mov_sp_r): Add support for -mtiny-stack.
	Write SPH before SPL.
	(*movqi): No need to disable interrupts for just one "out"
	in alternative 5.  Change length attribute from 4 to 1.
	* config/avr/libgcc.S (__prologue_saves__, __epilogue_restores__):
	Write SPH before SPL.

From-SVN: r34678