alpha.md (I24MODE): New mode iterator.

	* config/alpha/alpha.md (I24MODE): New mode iterator.
	(any_divmod): New code iterator.
	(<code>si3): Macroize expander from {div,mod,udiv,umod}si3 using
	any_divmod code iterator.
	(<code>si3): Macroize expander from {div,mod,udiv,umod}di3 using
	any_divmod code iterator.
	(extendqi<mode>2): Macroize insn from extendqi{hi,si}2 using
	I24MODE mode iterator.
	(unaligned_store<mode>): Macroize expander from unaligned_store{qi,hi}
	using I12MODE mode iterator.
	(mov<mode>): Macroize expander from mov{qi,hi} using
	I12MODE mode iterator.

From-SVN: r192427