Core 1148

	Core 1148
	* typeck.c (check_return_expr): Fix conditions for setting
	LOOKUP_PREFER_RVALUE.

From-SVN: r171071

gcc/cp/ChangeLog

 2011-03-16  Jason Merrill  <jason@redhat.com>
 
+	Core 1148
+	* typeck.c (check_return_expr): Fix conditions for setting
+	LOOKUP_PREFER_RVALUE.
+
 	* call.c (build_over_call): Remove require_complete_type_sfinae call.
 
 	PR c++/48132

gcc/cp/typeck.c

@@ -7760,12 +7760,19 @@ check_return_expr (tree retval, bool *no_warning)
 
       /* Under C++0x [12.8/16 class.copy], a returned lvalue is sometimes
 	 treated as an rvalue for the purposes of overload resolution to
-	 favor move constructors over copy constructors.  */
-      if ((cxx_dialect != cxx98) 
-          && named_return_value_okay_p
-          /* The variable must not have the `volatile' qualifier.  */
-	  && !CP_TYPE_VOLATILE_P (TREE_TYPE (retval))
-	  /* The return type must be a class type.  */
+	 favor move constructors over copy constructors.
+
+         Note that these conditions are similar to, but not as strict as,
+	 the conditions for the named return value optimization.  */
+      if ((cxx_dialect != cxx98)
+          && (TREE_CODE (retval) == VAR_DECL
+	      || TREE_CODE (retval) == PARM_DECL)
+	  && DECL_CONTEXT (retval) == current_function_decl
+	  && !TREE_STATIC (retval)
+	  && same_type_p ((TYPE_MAIN_VARIANT (TREE_TYPE (retval))),
+			  (TYPE_MAIN_VARIANT
+			   (TREE_TYPE (TREE_TYPE (current_function_decl)))))
+	  /* This is only interesting for class type.  */
 	  && CLASS_TYPE_P (TREE_TYPE (TREE_TYPE (current_function_decl))))
 	flags = flags | LOOKUP_PREFER_RVALUE;
 

gcc/testsuite/ChangeLog

 2011-03-16  Jason Merrill  <jason@redhat.com>
 
+	* g++.dg/cpp0x/elision2.C: New.
+
 	* g++.dg/cpp0x/constexpr-array3.C: New.
 
 2011-03-16  Jason Merrill  <jason@redhat.com>

gcc/testsuite/g++.dg/cpp0x/elision2.C

+// Core 1148: should be able to move from value parameter on return
+// { dg-options -std=c++0x }
+
+struct A
+{
+  A(const A&) = delete;
+  A(A&&);
+};
+
+A f (A a)
+{
+  return a;
+}