i386.md ("isa" attribute): Add x64_sse2.

i386.md ("isa" attribute): Add x64_sse2.

	* config/i386/i386.md ("isa" attribute): Add x64_sse2.
	("enabled" attribute): Handle "isa" attribute.
	(*movdi_internal): Substitute Yi and Yj constraint with x
	and Ym and Yn constraint with y constraint.  Update "isa"
	attribute and set "preferred_for_speed" attribute from
	TARGET_INTER_UNIT_MOVES_{FROM,TO}_VEC for updated alternatives.
	(*movsi_internal): Ditto.
	(*movdf_internal): Ditto.
	(*movsf_internal): Ditto.
	(*zero_extendsidi2): Ditto.
	* config/i386/sse.md (vec_set<mode>_0): Ditto.
	(sse2_loadld): Ditto.
	(*vec_extract<ssevecmodelower>_0): Ditto.
	(*vec_extractv4si_0_zext_sse4): Ditto.
	(vec_concatv2di): Ditto.
	(*vec_dup<mode>): Ditto.
	* config/i386/mmx.md (*mov<mode>_internal): Ditto.
	* config/i386/constraints.md (Yi): Remove.
	(Yj): Remove.
	(Ym): Remove.
	(Yn): Remove.

From-SVN: r259682