Enable vectorization for V2HF/V4HF rounding operations and sqrt.

Enable vectorization for V2HF/V4HF rounding operations and sqrt.

gcc/ChangeLog:

	* config/i386/i386-expand.cc (ix86_sse_copysign_to_positive):
	Handle HFmode.
	(ix86_expand_round_sse4): Ditto.
	* config/i386/i386.md (roundhf2): New expander.
	(lroundhf<mode>2): Ditto.
	(lrinthf<mode>2): Ditto.
	(l<rounding_insn>hf<mode>2): Ditto.
	* config/i386/mmx.md (sqrt<mode>2): Ditto.
	(btrunc<mode>2): Ditto.
	(nearbyint<mode>2): Ditto.
	(rint<mode>2): Ditto.
	(lrint<mode><mmxintvecmodelower>2): Ditto.
	(floor<mode>2): Ditto.
	(lfloor<mode><mmxintvecmodelower>2): Ditto.
	(ceil<mode>2): Ditto.
	(lceil<mode><mmxintvecmodelower>2): Ditto.
	(round<mode>2): Ditto.
	(lround<mode><mmxintvecmodelower>2): Ditto.
	* config/i386/sse.md (lrint<mode><sseintvecmodelower>2): Ditto.
	(lfloor<mode><sseintvecmodelower>2): Ditto.
	(lceil<mode><sseintvecmodelower>2): Ditto.
	(lround<mode><sseintvecmodelower>2): Ditto.
	(sse4_1_round<ssescalarmodesuffix>): Extend to V8HF.
	(round<mode>2): Extend to V8HF/V16HF/V32HF.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/part-vect-roundhf.c: New test.
	* gcc.target/i386/part-vect-sqrtph-1.c: New test.