diff --git a/clang/utils/TableGen/ClangDiagnosticsEmitter.cpp b/clang/utils/TableGen/ClangDiagnosticsEmitter.cpp
index db159d1..2c265af 100644
--- a/clang/utils/TableGen/ClangDiagnosticsEmitter.cpp
+++ b/clang/utils/TableGen/ClangDiagnosticsEmitter.cpp
@@ -472,6 +472,11 @@
   return ClsName == "CLASS_ERROR";
 }
 
+static bool isRemark(const Record &Diag) {
+  const std::string &ClsName = Diag.getValueAsDef("Class")->getName();
+  return ClsName == "CLASS_REMARK";
+}
+
 /// ClangDiagsDefsEmitter - The top-level class emits .def files containing
 /// declarations of Clang diagnostics.
 namespace clang {
@@ -518,6 +523,14 @@
       }
     }
 
+    // Check that all remarks have an associated diagnostic group.
+    if (isRemark(R)) {
+      if (!isa<DefInit>(R.getValueInit("Group"))) {
+        PrintFatalError(R.getLoc(), "Error " + R.getName() +
+                                        " not in any diagnostic group");
+      }
+    }
+
     // Filter by component.
     if (!Component.empty() && Component != R.getValueAsString("Component"))
       continue;