C++14 constexpr support (minus loops and multiple returns)
gcc/
	* tree-inline.c (copy_fn): New.
	* tree-inline.h: Declare it.
gcc/cp/
	* constexpr.c (use_new_call): New macro.
	(build_data_member_initialization): Ignore non-mem-inits.
	(check_constexpr_bind_expr_vars): Remove C++14 checks.
	(constexpr_fn_retval): Likewise.
	(check_constexpr_ctor_body): Do nothing in C++14.
	(massage_constexpr_body): In C++14 only collect mem-inits.
	(get_function_named_in_call): Handle null CALL_EXPR_FN.
	(cxx_bind_parameters_in_call): Build bindings in same order as
	parameters.  Don't treat iniviref parms specially in new call mode.
	(cxx_eval_call_expression): If use_new_call, do constexpr expansion
	based on DECL_SAVED_TREE rather than the massaged constexpr body.
	Set up ctx->object from AGGR_INIT_EXPR_SLOT if we don't have one.
	(is_sub_constant_expr): Don't mess with ctx.ctor here.
	(cxx_eval_component_reference): A null element means we're mid-
	initialization.
	(cxx_eval_store_expression, cxx_eval_increment_expression): New.
	(cxx_eval_constant_expression): Handle RESULT_DECL, DECL_EXPR,
	MODIFY_EXPR, STATEMENT_LIST, BIND_EXPR, USING_STMT,
	PREINCREMENT_EXPR, POSTINCREMENT_EXPR, PREDECREMENT_EXPR,
	POSTDECREMENT_EXPR.  Don't look into DECL_INITIAL of variables in
	constexpr functions.  In new-call mode find parms in the values table.
	(potential_constant_expression_1): Handle null CALL_EXPR_FN.
	Handle STATEMENT_LIST, MODIFY_EXPR, MODOP_EXPR, IF_STMT,
	PREINCREMENT_EXPR, POSTINCREMENT_EXPR, PREDECREMENT_EXPR,
	POSTDECREMENT_EXPR, BIND_EXPR, WITH_CLEANUP_EXPR,
	CLEANUP_POINT_EXPR, MUST_NOT_THROW_EXPR, TRY_CATCH_EXPR,
	EH_SPEC_BLOCK, EXPR_STMT, DECL_EXPR, CASE_LABEL_EXPR, BREAK_STMT,
	CONTINUE_STMT, USING_STMT, IF_STMT, DO_STMT, FOR_STMT, WHILE_STMT,
	SWITCH_STMT, ASM_EXPR.
	(cxx_eval_vec_init_1): Call build_aggr_init_expr.
	(cxx_eval_indirect_ref): Don't return a CONSTRUCTOR when the
	caller wants an lvalue.
	(cxx_eval_outermost_constant_expr): Pull object out of AGGR_INIT_EXPR.
	(maybe_constant_init): Look through INIT_EXPR.
	(ensure_literal_type_for_constexpr_object): Set
	cp_function_chain->invalid_constexpr.
	* cp-tree.h (struct language_function): Add invalid_constexpr bitfield.
	* decl.c (start_decl): Set cp_function_chain->invalid_constexpr.
	(check_for_uninitialized_const_var): Likewise.
	(maybe_save_function_definition): Check it.
	* parser.c (cp_parser_jump_statement): Set
	cp_function_chain->invalid_constexpr.
	(cp_parser_asm_definition): Likewise.

From-SVN: r217663