Lower VEC_COND_EXPR into internal functions.

Lower VEC_COND_EXPR into internal functions.

gcc/ChangeLog:

	* Makefile.in: Add new file.
	* expr.c (expand_expr_real_2): Add gcc_unreachable as we should
	not meet this condition.
	(do_store_flag): Likewise.
	* gimplify.c (gimplify_expr): Gimplify first argument of
	VEC_COND_EXPR to be a SSA name.
	* internal-fn.c (vec_cond_mask_direct): New.
	(vec_cond_direct): Likewise.
	(vec_condu_direct): Likewise.
	(vec_condeq_direct): Likewise.
	(expand_vect_cond_optab_fn):  New.
	(expand_vec_cond_optab_fn): Likewise.
	(expand_vec_condu_optab_fn): Likewise.
	(expand_vec_condeq_optab_fn): Likewise.
	(expand_vect_cond_mask_optab_fn): Likewise.
	(expand_vec_cond_mask_optab_fn): Likewise.
	(direct_vec_cond_mask_optab_supported_p): Likewise.
	(direct_vec_cond_optab_supported_p): Likewise.
	(direct_vec_condu_optab_supported_p): Likewise.
	(direct_vec_condeq_optab_supported_p): Likewise.
	* internal-fn.def (VCOND): New OPTAB.
	(VCONDU): Likewise.
	(VCONDEQ): Likewise.
	(VCOND_MASK): Likewise.
	* optabs.c (get_rtx_code): Make it global.
	(expand_vec_cond_mask_expr): Removed.
	(expand_vec_cond_expr): Removed.
	* optabs.h (expand_vec_cond_expr): Likewise.
	(vector_compare_rtx): Make it global.
	* passes.def: Add new pass_gimple_isel pass.
	* tree-cfg.c (verify_gimple_assign_ternary): Add check
	for VEC_COND_EXPR about first argument.
	* tree-pass.h (make_pass_gimple_isel): New.
	* tree-ssa-forwprop.c (pass_forwprop::execute): Prevent
	propagation of the first argument of a VEC_COND_EXPR.
	* tree-ssa-reassoc.c (ovce_extract_ops): Support SSA_NAME as
	first argument of a VEC_COND_EXPR.
	(optimize_vec_cond_expr): Likewise.
	* tree-vect-generic.c (expand_vector_divmod): Make SSA_NAME
	for a first argument of created VEC_COND_EXPR.
	(expand_vector_condition): Fix coding style.
	* tree-vect-stmts.c (vectorizable_condition): Gimplify
	first argument.
	* gimple-isel.cc: New file.

gcc/testsuite/ChangeLog:

	* g++.dg/vect/vec-cond-expr-eh.C: New test.