diff --git a/clang/include/clang/Driver/CLCompatOptions.td b/clang/include/clang/Driver/CLCompatOptions.td
index 34a1218b25e4..b2872d6bb874 100644
--- a/clang/include/clang/Driver/CLCompatOptions.td
+++ b/clang/include/clang/Driver/CLCompatOptions.td
@@ -61,6 +61,8 @@ def _SLASH_Brepro_ : CLFlag<"Brepro-">,
 def _SLASH_C : CLFlag<"C">,
   HelpText<"Don't discard comments when preprocessing">, Alias<C>;
 def _SLASH_c : CLFlag<"c">, HelpText<"Compile only">, Alias<c>;
+def _SLASH_d1PP : CLFlag<"d1PP">,
+  HelpText<"Retain macro definitions in /E mode">, Alias<dD>;
 def _SLASH_d1reportAllClassLayout : CLFlag<"d1reportAllClassLayout">,
   HelpText<"Dump record layout information">, Alias<fdump_record_layouts>;
 def _SLASH_diagnostics_caret : CLFlag<"diagnostics:caret">,
diff --git a/clang/test/Driver/cl-options.c b/clang/test/Driver/cl-options.c
index abe55b74946f..21d826473bf9 100644
--- a/clang/test/Driver/cl-options.c
+++ b/clang/test/Driver/cl-options.c
@@ -293,6 +293,9 @@
 // RUN: %clang_cl /TP /c /GX /GX- -### -- %s 2>&1 | FileCheck -check-prefix=GX_ %s
 // GX_-NOT: "-fcxx-exceptions" "-fexceptions"
 
+// RUN: %clang_cl /d1PP -### -- %s 2>&1 | FileCheck -check-prefix=d1PP %s
+// d1PP: -dD
+
 // We forward any unrecognized -W diagnostic options to cc1.
 // RUN: %clang_cl -Wunused-pragmas -### -- %s 2>&1 | FileCheck -check-prefix=WJoined %s
 // WJoined: "-cc1"