c++: Remove cdtor_label

Jakub pointed out that cdtor_label is unnecessary, we should get all the
desired semantics with a normal return.

gcc/cp/ChangeLog:

	* cp-tree.h (struct language_function): Remove x_cdtor_label.
	(cdtor_label, LABEL_DECL_CDTOR): Remove.
	* constexpr.cc (returns): Don't check LABEL_DECL_CDTOR.
	(cxx_eval_constant_expression): Don't call returns.
	* decl.cc (check_goto): Don't check cdtor_label.
	(start_preparsed_function): And don't set it.
	(finish_constructor_body, finish_destructor_body): Remove.
	(finish_function_body): Don't call them.
	* typeck.cc (check_return_expr): Handle cdtor_returns_this here.
	* semantics.cc (finish_return_stmt): Not here.

1 files changed, 10 insertions, 2 deletions

diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 0da6f24..57e55ed 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -10447,7 +10447,11 @@ check_return_expr (tree retval, bool *no_warning)
     {
       if (retval)
 	error_at (loc, "returning a value from a destructor");
-      return NULL_TREE;
+
+      if (targetm.cxx.cdtor_returns_this ())
+	retval = current_class_ptr;
+      else
+	return NULL_TREE;
     }
   else if (DECL_CONSTRUCTOR_P (current_function_decl))
     {
@@ -10458,7 +10462,11 @@ check_return_expr (tree retval, bool *no_warning)
       else if (retval)
 	/* You can't return a value from a constructor.  */
 	error_at (loc, "returning a value from a constructor");
-      return NULL_TREE;
+
+      if (targetm.cxx.cdtor_returns_this ())
+	retval = current_class_ptr;
+      else
+	return NULL_TREE;
     }
 
   const tree saved_retval = retval;