Correct sparc's REGMODE_NATURAL_SIZE and MODES_TIEABLE_P wrt. vector modes.

Correct sparc's REGMODE_NATURAL_SIZE and MODES_TIEABLE_P wrt. vector modes.

	* config/sparc/sparc.c (sparc_regmode_natural_size): New function
	implementing REGMODE_NATURAL_SIZE taking into consideration vector
	modes.
	(sparc_modes_tieable_p): Similarly for MODES_TIEABLE_P.
	* config/sparc/sparc-protos.h (sparc_regmode_natural_size,
	sparc_modes_tieable_p): Declare.
	* gcc/config/sparc/sparc.h (REGMODE_NATURAL_SIZE,
	MODES_TIEABLE_P): Use new helper functions.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@181599 138bc75d-0d04-0410-961f-82ee72b054a4