diff --git a/clang/include/clang/AST/CommentCommands.td b/clang/include/clang/AST/CommentCommands.td
--- a/clang/include/clang/AST/CommentCommands.td
+++ b/clang/include/clang/AST/CommentCommands.td
@@ -154,7 +154,7 @@
 def Pre        : BlockCommand<"pre">;
 def Remark     : BlockCommand<"remark">;
 def Remarks    : BlockCommand<"remarks">;
-def Retval     : BlockCommand<"retval">;
+def Retval     : BlockCommand<"retval"> { let NumArgs = 1; }
 def Sa         : BlockCommand<"sa">;
 def See        : BlockCommand<"see">;
 def Since      : BlockCommand<"since">;
@@ -162,7 +162,7 @@
 def Todo       : BlockCommand<"todo">;
 def Version    : BlockCommand<"version">;
 def Warning    : BlockCommand<"warning">;
-def XRefItem   : BlockCommand<"xrefitem">;
+def XRefItem   : BlockCommand<"xrefitem"> { let NumArgs = 3; }
 // HeaderDoc commands
 def Abstract      : BlockCommand<"abstract"> { let IsBriefCommand = 1; }
 def ClassDesign   : RecordLikeDetailCommand<"classdesign">;
diff --git a/clang/test/AST/ast-dump-comment.cpp b/clang/test/AST/ast-dump-comment.cpp
--- a/clang/test/AST/ast-dump-comment.cpp
+++ b/clang/test/AST/ast-dump-comment.cpp
@@ -32,6 +32,13 @@
 // CHECK-NEXT:     ParagraphComment
 // CHECK-NEXT:       TextComment{{.*}} Text=" Aaa"
 
+/// \retval 42 Aaa
+int Test_BlockCommandComment_WithArgs();
+// CHECK:      FunctionDecl{{.*}}Test_BlockCommandComment_WithArgs
+// CHECK:        BlockCommandComment{{.*}} Name="retval" Arg[0]="42"
+// CHECK-NEXT:     ParagraphComment
+// CHECK-NEXT:       TextComment{{.*}} Text=" Aaa"
+
 /// \param Aaa xxx
 /// \param [in,out] Bbb yyy
 void Test_ParamCommandComment(int Aaa, int Bbb);
diff --git a/clang/test/Sema/warn-documentation.cpp b/clang/test/Sema/warn-documentation.cpp
--- a/clang/test/Sema/warn-documentation.cpp
+++ b/clang/test/Sema/warn-documentation.cpp
@@ -189,6 +189,14 @@
 int test_multiple_returns4(int);
 
 
+/// expected-warning@+1 {{empty paragraph passed to '\retval' command}}
+/// \retval 0
+int test_retval_no_paragraph();
+
+/// \retval 0 Everything is fine.
+int test_retval_fine();
+
+
 // expected-warning@+1 {{'\param' command used in a comment that is not attached to a function declaration}}
 /// \param a Blah blah.
 int test_param1_backslash;