PR tree-optimization/24659
        * optabs.h (enum optab_index): Add OTI_vec_unpacks_float_hi,
	OTI_vec_unpacks_float_lo, OTI_vec_unpacku_float_hi,
	OTI_vec_unpacku_float_lo, OTI_vec_pack_sfix_trunc and
	OTI_vec_pack_ufix_trunc.
	(vec_unpacks_float_hi_optab): Define new macro.
	(vec_unpacks_float_lo_optab): Ditto.
	(vec_unpacku_float_hi_optab): Ditto.
	(vec_unpacku_float_lo_optab): Ditto.
	(vec_pack_sfix_trunc_optab): Ditto.
	(vec_pack_ufix_trunc_optab): Ditto.
	* genopinit.c (optabs): Implement vec_unpack[s|u]_[hi|lo]_optab
	and vec_pack_[s|u]fix_trunc_optab using
	vec_unpack[s|u]_[hi\lo]_* and vec_pack_[u|s]fix_trunc_* patterns
	* tree-vectorizer.c (supportable_widening_operation): Handle
	FLOAT_EXPR and CONVERT_EXPR.  Update comment.
	(supportable_narrowing_operation): New function.
	* tree-vectorizer.h (supportable_narrowing_operation): Prototype.
	* tree-vect-transform.c (vectorizable_conversion): Handle
	(nunits_in == nunits_out / 2) and (nunits_out == nunits_in / 2) cases.
	(vect_gen_widened_results_half): Move before vectorizable_conversion.
	(vectorizable_type_demotion): Call supportable_narrowing_operation()
	to check for target support.
	* optabs.c (optab_for_tree_code) Return vec_unpack[s|u]_float_hi_optab
	for VEC_UNPACK_FLOAT_HI_EXPR, vec_unpack[s|u]_float_lo_optab
	for VEC_UNPACK_FLOAT_LO_EXPR and vec_pack_[u|s]fix_trunc_optab
	for VEC_PACK_FIX_TRUNC_EXPR.
	(expand_binop): Special case mode of the result for
	vec_pack_[u|s]fix_trunc_optab.
	(init_optabs): Initialize vec_unpack[s|u]_[hi|lo]_optab and
	vec_pack_[u|s]fix_trunc_optab.

	* tree.def (VEC_UNPACK_FLOAT_HI_EXPR, VEC_UNPACK_FLOAT_LO_EXPR,
	VEC_PACK_FIX_TRUNC_EXPR): New tree codes.
	* tree-pretty-print.c (dump_generic_node): Handle
	VEC_UNPACK_FLOAT_HI_EXPR, VEC_UNPACK_FLOAT_LO_EXPR and
	VEC_PACK_FIX_TRUNC_EXPR.
	(op_prio): Ditto.
	* expr.c (expand_expr_real_1): Ditto.
	* tree-inline.c (estimate_num_insns_1): Ditto.
	* tree-vect-generic.c (expand_vector_operations_1): Ditto.

	* config/i386/sse.md (vec_unpacks_float_hi_v8hi): New expander.
	(vec_unpacks_float_lo_v8hi): Ditto.
	(vec_unpacku_float_hi_v8hi): Ditto.
	(vec_unpacku_float_lo_v8hi): Ditto.
	(vec_unpacks_float_hi_v4si): Ditto.
	(vec_unpacks_float_lo_v4si): Ditto.
	(vec_pack_sfix_trunc_v2df): Ditto.

	* doc/c-tree.texi (Expression trees) [VEC_UNPACK_FLOAT_HI_EXPR]:
	Document.
	[VEC_UNPACK_FLOAT_LO_EXPR]: Ditto.
	[VEC_PACK_FIX_TRUNC_EXPR]: Ditto.
	* doc/md.texi (Standard Names) [vec_pack_sfix_trunc]: Document.
	[vec_pack_ufix_trunc]: Ditto.
	[vec_unpacks_float_hi]: Ditto.
	[vec_unpacks_float_lo]: Ditto.
	[vec_unpacku_float_hi]: Ditto.
	[vec_unpacku_float_lo]: Ditto.

testsuite/ChangeLog:

	PR tree-optimization/24659
	* gcc.dg/vect/vect-floatint-conversion-2.c: New test.
	* gcc.dg/vect/vect-intfloat-conversion-1.c: Require vect_float,
	not vect_int target.
	* gcc.dg/vect/vect-intfloat-conversion-2.c: Require vect_float,
	not vect_int target.  Loop is vectorized for vect_intfloat_cvt
	targets.
	* gcc.dg/vect/vect-intfloat-conversion-3.c: New test.
	* gcc.dg/vect/vect-intfloat-conversion-4a.c: New test.
	* gcc.dg/vect/vect-intfloat-conversion-4b.c: New test.

From-SVN: r124784