Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -5518,13 +5518,22 @@
   case Stmt::CXXMemberCallExprClass: {
     const CallExpr *CE = cast<CallExpr>(E);
     if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
-      if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
+      bool IsFirst = true;
+      StringLiteralCheckType CommonResult;
+      for (const auto *FA : ND->specific_attrs<FormatArgAttr>()) {
         const Expr *Arg = CE->getArg(FA->getFormatIdx().getASTIndex());
-        return checkFormatStringExpr(S, Arg, Args,
-                                     HasVAListArg, format_idx, firstDataArg,
-                                     Type, CallType, InFunctionCall,
-                                     CheckedVarArgs, UncoveredArg, Offset);
-      } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
+        StringLiteralCheckType Result = checkFormatStringExpr(
+            S, Arg, Args, HasVAListArg, format_idx, firstDataArg, Type,
+            CallType, InFunctionCall, CheckedVarArgs, UncoveredArg, Offset);
+        if (IsFirst) {
+          CommonResult = Result;
+          IsFirst = false;
+        }
+      }
+      if (!IsFirst)
+        return CommonResult;
+
+      if (const auto *FD = dyn_cast<FunctionDecl>(ND)) {
         unsigned BuiltinID = FD->getBuiltinID();
         if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString ||
             BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) {
Index: test/Sema/attr-format_arg.c
===================================================================
--- test/Sema/attr-format_arg.c
+++ test/Sema/attr-format_arg.c
@@ -4,10 +4,27 @@
 
 const char* f(const char *s) __attribute__((format_arg(1)));
 
+const char *h(const char *msg1, const char *msg2)
+    __attribute__((__format_arg__(1))) __attribute__((__format_arg__(2)));
+
 void g(const char *s) {
   printf("%d", 123);
   printf("%d %d", 123); // expected-warning{{more '%' conversions than data arguments}}
 
   printf(f("%d"), 123);
   printf(f("%d %d"), 123); // expected-warning{{more '%' conversions than data arguments}}
+
+  printf(h(
+    "", // expected-warning {{format string is empty}}
+    ""  // expected-warning {{format string is empty}}
+  ), 123);
+  printf(h(
+    "%d",
+    ""  // expected-warning {{format string is empty}}
+  ), 123);
+  printf(h(
+    "", // expected-warning {{format string is empty}}
+    "%d"
+  ), 123);
+  printf(h("%d", "%d"), 123);
 }