diff --git a/test/Driver/m_and_mm.c b/test/Driver/m_and_mm.c
index e4d59bc..6e40c82 100644
--- a/test/Driver/m_and_mm.c
+++ b/test/Driver/m_and_mm.c
@@ -5,7 +5,7 @@
 // RUN: %clang -M -MM %s 2> %t
 // RUN: not grep "warning" %t
 
-// RUN: %clang -MMD -MD %s 2> %t
+// RUN: %clang -MMD -MD %s 2> %t || true
 // RUN: grep "warning" %t
 
 #warning "This warning shouldn't show up with -M and -MM"