Index: lib/Sema/SemaInit.cpp
===================================================================
--- lib/Sema/SemaInit.cpp
+++ lib/Sema/SemaInit.cpp
@@ -885,8 +885,15 @@
       StructuredSubobjectInitList->setRBraceLoc(EndLoc);
     }
 
-    // Complain about missing braces.
-    if (T->isArrayType() || T->isRecordType()) {
+    // Complain about missing braces when rhs is not a macro from system header.
+    // getSpellingLoc() isn't cheap, so only call it if the warning is enabled.
+    if ((T->isArrayType() || T->isRecordType()) &&
+        !SemaRef.Diags.isIgnored(diag::warn_missing_braces,
+                                 StructuredSubobjectInitList->getLocStart())) {
+      SourceLocation SpellingLoc = SemaRef.getSourceManager().getSpellingLoc(StructuredSubobjectInitList->getLocStart());
+      if (SpellingLoc.isValid() &&
+          SemaRef.getSourceManager().isInSystemHeader(SpellingLoc))
+        return;
       SemaRef.Diag(StructuredSubobjectInitList->getLocStart(),
                    diag::warn_missing_braces)
           << StructuredSubobjectInitList->getSourceRange()
Index: test/Sema/warn-missing-braces.c
===================================================================
--- test/Sema/warn-missing-braces.c
+++ test/Sema/warn-missing-braces.c
@@ -1,3 +1,21 @@
 // RUN: %clang_cc1 -fsyntax-only -Wmissing-braces -verify %s
 
+#ifdef BE_THE_HEADER
+#pragma clang system_header
+
+typedef struct _foo {
+    unsigned char Data[2];
+} foo;
+
+#define BAR { 0 }
+
+#else
+
+#define BE_THE_HEADER
+#include __FILE__
+
 int a[2][2] = { 0, 1, 2, 3 }; // expected-warning{{suggest braces}} expected-warning{{suggest braces}}
+
+foo g = BAR; // should not show warnings
+
+#endif