diff --git a/clang/lib/Headers/stdnoreturn.h b/clang/lib/Headers/stdnoreturn.h
index 92fd4a98a87bf..944e6904c7df6 100644
--- a/clang/lib/Headers/stdnoreturn.h
+++ b/clang/lib/Headers/stdnoreturn.h
@@ -15,11 +15,13 @@
 
 #if __STDC_VERSION__ > 201710L &&                                              \
     !defined(_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS)
-/* The noreturn macro is deprecated in C2x. */
-#pragma clang deprecated(noreturn)
-
-/* Including the header file in C2x is also deprecated. */
-#warning "the '<stdnoreturn.h>' header is deprecated in C2x"
+/* The noreturn macro is deprecated in C2x. We do not mark it as such because
+   including the header file in C2x is also deprecated and we do not want to
+   issue a confusing diagnostic for code which includes <stdnoreturn.h>
+   followed by code that writes [[noreturn]]. The issue with such code is not
+   with the attribute, or the use of 'noreturn', but the inclusion of the
+   header. */
+#warning "the '<stdnoreturn.h>' header is deprecated in C2x; either use the '_Noreturn' keyword or the '[[noreturn]]' attribute"
 #endif
 
 #endif /* __STDNORETURN_H */
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 6d0c8f0974767..3034abdf04028 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -2177,9 +2177,14 @@ static void handleNoReturnAttr(Sema &S, Decl *D, const ParsedAttr &Attrs) {
 
 static void handleStandardNoReturnAttr(Sema &S, Decl *D, const ParsedAttr &A) {
   // The [[_Noreturn]] spelling is deprecated in C2x, so if that was used,
-  // issue an appropriate diagnostic.
+  // issue an appropriate diagnostic. However, don't issue a diagnostic if the
+  // attribute name comes from a macro expansion. We don't want to punish users
+  // who write [[noreturn]] after including <stdnoreturn.h> (where 'noreturn'
+  // is defined as a macro which expands to '_Noreturn').
   if (!S.getLangOpts().CPlusPlus &&
-      A.getSemanticSpelling() == CXX11NoReturnAttr::C2x_Noreturn)
+      A.getSemanticSpelling() == CXX11NoReturnAttr::C2x_Noreturn &&
+      !(A.getLoc().isMacroID() &&
+        S.getSourceManager().isInSystemMacro(A.getLoc())))
     S.Diag(A.getLoc(), diag::warn_deprecated_noreturn_spelling) << A.getRange();
 
   D->addAttr(::new (S.Context) CXX11NoReturnAttr(S.Context, A));
diff --git a/clang/test/Sema/c2x-noreturn.c b/clang/test/Sema/c2x-noreturn.c
index e522a43cf6eba..6c119736f6454 100644
--- a/clang/test/Sema/c2x-noreturn.c
+++ b/clang/test/Sema/c2x-noreturn.c
@@ -36,29 +36,30 @@ _Noreturn void func1(void); // ok, using the function specifier
 [[_Noreturn]] void func3(void); // all-warning {{the '[[_Noreturn]]' attribute spelling is deprecated in C2x; use '[[noreturn]]' instead}}
 
 // Test the behavior of including <stdnoreturn.h>
-#include <stdnoreturn.h> // c2x-warning@stdnoreturn.h:* {{the '<stdnoreturn.h>' header is deprecated in C2x}}
+#include <stdnoreturn.h> // c2x-warning@stdnoreturn.h:* {{the '<stdnoreturn.h>' header is deprecated in C2x; either use the '_Noreturn' keyword or the '[[noreturn]]' attribute}}
 
-[[noreturn]] void func6(void); // all-warning {{the '[[_Noreturn]]' attribute spelling is deprecated in C2x; use '[[noreturn]]' instead}} \
-                               // c2x-warning {{macro 'noreturn' has been marked as deprecated}} \
-                               // c2x-note@stdnoreturn.h:* {{macro marked 'deprecated' here}}
+[[noreturn]] void func6(void);
 
-void func7 [[noreturn]] (void); // all-warning {{the '[[_Noreturn]]' attribute spelling is deprecated in C2x; use '[[noreturn]]' instead}} \
-                                // c2x-warning {{macro 'noreturn' has been marked as deprecated}} \
-                                // c2x-note@stdnoreturn.h:* {{macro marked 'deprecated' here}}
+void func7 [[noreturn]] (void);
 
-noreturn void func8(void); // c2x-warning {{macro 'noreturn' has been marked as deprecated}} \
-                           // c2x-note@stdnoreturn.h:* {{macro marked 'deprecated' here}}
+noreturn void func8(void);
 
-// Ensure the function specifier form still works
-void noreturn func9(void); // c2x-warning {{macro 'noreturn' has been marked as deprecated}} \
-                           // c2x-note@stdnoreturn.h:* {{macro marked 'deprecated' here}}
+// Ensure the function specifier form still works.
+void noreturn func9(void);
+
+// Ensure that spelling the deprecated form of the attribute is still diagnosed.
+[[_Noreturn]] void func10(void); // all-warning {{the '[[_Noreturn]]' attribute spelling is deprecated in C2x; use '[[noreturn]]' instead}}
 
 // Test preprocessor functionality after including <stdnoreturn.h>.
-#if !__has_c_attribute(noreturn) // c2x-warning {{macro 'noreturn' has been marked as deprecated}} \
-                                 // c2x-note@stdnoreturn.h:* {{macro marked 'deprecated' here}}
+#if !__has_c_attribute(noreturn)
 #error "No noreturn attribute support?"
 #endif
 
 #if !__has_c_attribute(_Noreturn)
 #error "No _Noreturn attribute support?"
 #endif
+
+// Test that a macro which expands to _Noreturn is still diagnosed when it
+// doesn't come from a system header.
+#define NORETURN _Noreturn
+[[NORETURN]] void func11(void); // all-warning {{the '[[_Noreturn]]' attribute spelling is deprecated in C2x; use '[[noreturn]]' instead}}