1 files changed, 10 insertions, 0 deletions
diff --git a/clang/lib/Frontend/TextDiagnosticPrinter.cpp b/clang/lib/Frontend/TextDiagnosticPrinter.cpp
index 30da72b4a9b..d07917f2349 100644
--- a/clang/lib/Frontend/TextDiagnosticPrinter.cpp
+++ b/clang/lib/Frontend/TextDiagnosticPrinter.cpp
@@ -79,6 +79,16 @@ static void printDiagnosticOptions(raw_ostream &OS,
       Started = true;
     }
 
+    // If the diagnostic is an extension diagnostic and not enabled by default
+    // then it must have been turned on with -pedantic.
+    bool EnabledByDefault;
+    if (DiagnosticIDs::isBuiltinExtensionDiag(Info.getID(),
+                                              EnabledByDefault) &&
+        !EnabledByDefault) {
+      OS << (Started ? "," : " [") << "-pedantic";
+      Started = true;
+    }
+
     StringRef Opt = DiagnosticIDs::getWarningOptionForDiag(Info.getID());
     if (!Opt.empty()) {
       OS << (Started ? "," : " [") << "-W" << Opt;