Adjust by-value function vec arguments to by-reference.

Adjust by-value function vec arguments to by-reference.

gcc/c/ChangeLog:

	* c-parser.c (c_parser_declaration_or_fndef): Adjust by-value function
	vec arguments to by-reference.
	(c_finish_omp_declare_simd): Same.
	(c_parser_compound_statement_nostart): Same.
	(c_parser_for_statement): Same.
	(c_parser_objc_methodprotolist): Same.
	(c_parser_oacc_routine): Same.
	(c_parser_omp_for_loop): Same.
	(c_parser_omp_declare_simd): Same.

gcc/ChangeLog:

	* dominance.c (prune_bbs_to_update_dominators): Adjust by-value vec
	arguments to by-reference.
	(iterate_fix_dominators): Same.
	* dominance.h (iterate_fix_dominators): Same.
	* ipa-prop.h: Call auto_vec::to_vec_legacy.
	* tree-data-ref.c (dump_data_dependence_relation): Adjust by-value vec
	arguments to by-reference.
	(debug_data_dependence_relation): Same.
	(dump_data_dependence_relations): Same.
	* tree-data-ref.h (debug_data_dependence_relation): Same.
	(dump_data_dependence_relations): Same.
	* tree-predcom.c (dump_chains): Same.
	(initialize_root_vars_lm): Same.
	(determine_unroll_factor): Same.
	(replace_phis_by_defined_names): Same.
	(insert_init_seqs): Same.
	(pcom_worker::tree_predictive_commoning_loop): Call
	 auto_vec::to_vec_legacy.
	* tree-ssa-pre.c (insert_into_preds_of_block): Adjust by-value vec
	arguments to by-reference.
	* tree-ssa-threadbackward.c (populate_worklist): Same.
	(back_threader::resolve_def): Same.
	* tree-vect-data-refs.c (vect_check_nonzero_value): Same.
	(vect_enhance_data_refs_alignment): Same.
	(vect_check_lower_bound): Same.
	(vect_prune_runtime_alias_test_list): Same.
	(vect_permute_store_chain): Same.
	* tree-vect-slp-patterns.c (vect_normalize_conj_loc): Same.
	* tree-vect-stmts.c (vect_create_vectorized_demotion_stmts): Same.
	* tree-vectorizer.h (vect_permute_store_chain): Same.
	* vec.c (test_init): New function.
	(vec_c_tests): Call new function.
	* vec.h (vec): Declare ctors, dtor, and assignment.
	(auto_vec::vec_to_legacy): New function.
	(vec::copy): Adjust initialization.