Index: lib/Frontend/PrintPreprocessedOutput.cpp
===================================================================
--- lib/Frontend/PrintPreprocessedOutput.cpp
+++ lib/Frontend/PrintPreprocessedOutput.cpp
@@ -555,7 +555,7 @@
 PragmaAssumeNonNullBegin(SourceLocation Loc) {
   startNewLineIfNeeded();
   MoveToLine(Loc);
-  OS << "#pragma " << "clang assume_nonnull begin";
+  OS << "#pragma clang assume_nonnull begin";
   setEmittedDirectiveOnThisLine();
 }
 
@@ -563,7 +563,7 @@
 PragmaAssumeNonNullEnd(SourceLocation Loc) {
   startNewLineIfNeeded();
   MoveToLine(Loc);
-  OS << "#pragma " << "clang assume_nonnull end";
+  OS << "#pragma clang assume_nonnull end";
   setEmittedDirectiveOnThisLine();
 }
 
Index: test/Preprocessor/pragma_assume_nonnull.c
===================================================================
--- test/Preprocessor/pragma_assume_nonnull.c
+++ test/Preprocessor/pragma_assume_nonnull.c
@@ -1,23 +1,13 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
 // RUN: %clang_cc1 -E %s | FileCheck %s
 
-#ifndef NS_ASSUME_NONNULL_BEGIN
-#if __has_feature(assume_nonnull)
-#define NS_ASSUME_NONNULL_BEGIN _Pragma("clang assume_nonnull begin")
-#define NS_ASSUME_NONNULL_END _Pragma("clang assume_nonnull end")
-#else
-#define NS_ASSUME_NONNULL_BEGIN
-#define NS_ASSUME_NONNULL_END
-#endif
-#endif
-
 // CHECK: #pragma clang assume_nonnull begin
-NS_ASSUME_NONNULL_BEGIN
+#pragma clang assume_nonnull begin
 
 int bar(int * ip) { return *ip; }
 
 // CHECK: #pragma clang assume_nonnull end
-NS_ASSUME_NONNULL_END
+#pragma clang assume_nonnull end
 
 int foo(int * _Nonnull ip) { return *ip; }
 
@@ -28,4 +18,3 @@
    return bar(0) + foo(0); // expected-warning {{null passed to a callee that requires a non-null argument}}
 #endif
 }
-