diff --git a/clang/lib/Headers/intrin.h b/clang/lib/Headers/intrin.h
index 268ac4a17b85..d68fdfc7a395 100644
--- a/clang/lib/Headers/intrin.h
+++ b/clang/lib/Headers/intrin.h
@@ -97,6 +97,7 @@ static __inline__
 void __movsd(unsigned long *, unsigned long const *, size_t);
 static __inline__
 void __movsw(unsigned short *, unsigned short const *, size_t);
+static __inline__
 void __nop(void);
 void __nvreg_restore_fence(void);
 void __nvreg_save_fence(void);
@@ -918,6 +919,10 @@ static __inline__ void __DEFAULT_FN_ATTRS
 __halt(void) {
   __asm__ volatile ("hlt");
 }
+static __inline__ void __DEFAULT_FN_ATTRS
+__nop(void) {
+  __asm__ volatile ("nop");
+}
 #endif
 
 /*----------------------------------------------------------------------------*\
diff --git a/clang/test/Headers/ms-intrin.cpp b/clang/test/Headers/ms-intrin.cpp
index 25c5531c41f4..4d6803a08186 100644
--- a/clang/test/Headers/ms-intrin.cpp
+++ b/clang/test/Headers/ms-intrin.cpp
@@ -52,6 +52,7 @@ void f() {
   __cpuidex(info, 0, 0);
   _xgetbv(0);
   __halt();
+  __nop();
   __readmsr(0);
 
   // FIXME: Call these in 64-bit too once the intrinsics have been fixed to