diff --git a/test/Format/cursor.cpp b/test/Format/cursor.cpp
index d9aab5acb63505e5045d79d6567ce926f0c3dd26..c7d576ba6e6442a5ff81affb23a8cafc3d55408d 100644
--- a/test/Format/cursor.cpp
+++ b/test/Format/cursor.cpp
@@ -1,6 +1,6 @@
 // RUN: grep -Ev "// *[A-Z-]+:" %s > %t2.cpp
 // RUN: clang-format -style=LLVM %t2.cpp -cursor=6 > %t.cpp
 // RUN: FileCheck -strict-whitespace -input-file=%t.cpp %s
-// CHECK: {{^\{ "Cursor": 4 \}$}}
+// CHECK: {{^\{ "Cursor": 4, }}
 // CHECK: {{^int\ \i;$}}
  int    i;
diff --git a/test/Format/incomplete.cpp b/test/Format/incomplete.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..bd2c74ca3c17afd140f2e8ea07475cbed716b41d
--- /dev/null
+++ b/test/Format/incomplete.cpp
@@ -0,0 +1,8 @@
+// RUN: grep -Ev "// *[A-Z-]+:" %s > %t2.cpp
+// RUN: clang-format -style=LLVM %t2.cpp -cursor=0 > %t.cpp
+// RUN: FileCheck -strict-whitespace -input-file=%t.cpp %s
+// CHECK: {{"IncompleteFormat": true}}
+// CHECK: {{^int\ \i;$}}
+ int    i;
+// CHECK: {{^f  \( g  \(;$}}
+f  ( g  (;
diff --git a/tools/clang-format/ClangFormat.cpp b/tools/clang-format/ClangFormat.cpp
index fe7d678852d9d99d3d6e067f82b8dbf48b9eb424..5037e901f3b41c42c59d181d7db866d3e8bfba77 100644
--- a/tools/clang-format/ClangFormat.cpp
+++ b/tools/clang-format/ClangFormat.cpp
@@ -225,14 +225,18 @@ static bool format(StringRef FileName) {
 
   FormatStyle FormatStyle = getStyle(
       Style, (FileName == "-") ? AssumeFilename : FileName, FallbackStyle);
-  tooling::Replacements Replaces = reformat(FormatStyle, Sources, ID, Ranges);
+  bool IncompleteFormat = false;
+  tooling::Replacements Replaces =
+      reformat(FormatStyle, Sources, ID, Ranges, &IncompleteFormat);
   if (OutputXML) {
-    llvm::outs()
-        << "<?xml version='1.0'?>\n<replacements xml:space='preserve'>\n";
+    llvm::outs() << "<?xml version='1.0'?>\n<replacements "
+                    "xml:space='preserve' incomplete_format='"
+                 << (IncompleteFormat ? "true" : "false") << "'>\n";
     if (Cursor.getNumOccurrences() != 0)
       llvm::outs() << "<cursor>"
                    << tooling::shiftedCodePosition(Replaces, Cursor)
                    << "</cursor>\n";
+
     for (tooling::Replacements::const_iterator I = Replaces.begin(),
                                                E = Replaces.end();
          I != E; ++I) {
@@ -254,7 +258,9 @@ static bool format(StringRef FileName) {
     } else {
       if (Cursor.getNumOccurrences() != 0)
         outs() << "{ \"Cursor\": "
-               << tooling::shiftedCodePosition(Replaces, Cursor) << " }\n";
+               << tooling::shiftedCodePosition(Replaces, Cursor)
+               << ", \"IncompleteFormat\": "
+               << (IncompleteFormat ? "true" : "false") << " }\n";
       Rewrite.getEditBuffer(ID).write(outs());
     }
   }
diff --git a/tools/clang-format/clang-format.el b/tools/clang-format/clang-format.el
index add2436bbe79bd9ad294e844663696439a00cdf7..ca461444e22684186ed64aa16d10b226fce881a6 100644
--- a/tools/clang-format/clang-format.el
+++ b/tools/clang-format/clang-format.el
@@ -61,6 +61,7 @@ of the buffer."
   (unless (and (listp xml-node) (eq (xml-node-name xml-node) 'replacements))
     (error "Expected <replacements> node"))
   (let ((nodes (xml-node-children xml-node))
+        (incomplete-format (xml-get-attribute xml-node 'incomplete_format))
         replacements
         cursor)
     (dolist (node nodes)
@@ -89,7 +90,7 @@ of the buffer."
                                    (and (= (car a) (car b))
                                         (> (cadr a) (cadr b)))))))
 
-    (cons replacements cursor)))
+    (list replacements cursor (string= incomplete-format "true"))))
 
 (defun clang-format--replace (offset length &optional text)
   (let ((start (byte-to-position (1+ offset)))
@@ -142,20 +143,24 @@ is no active region.  If no style is given uses `clang-format-style'."
            ((stringp status)
             (error "(clang-format killed by signal %s%s)" status stderr))
            ((not (equal 0 status))
-            (error "(clang-format failed with code %d%s)" status stderr))
-           (t (message "(clang-format succeeded%s)" stderr)))
+            (error "(clang-format failed with code %d%s)" status stderr)))
 
           (with-current-buffer temp-buffer
             (setq operations (clang-format--extract (car (xml-parse-region)))))
 
-          (let ((replacements (car operations))
-                (cursor (cdr operations)))
+          (let ((replacements (nth 0 operations))
+                (cursor (nth 1 operations))
+                (incomplete-format (nth 2 operations)))
             (save-excursion
               (mapc (lambda (rpl)
                       (apply #'clang-format--replace rpl))
                     replacements))
             (when cursor
-              (goto-char (byte-to-position (1+ cursor))))))
+              (goto-char (byte-to-position (1+ cursor))))
+            (message "%s" incomplete-format)
+            (if incomplete-format
+                (message "(clang-format: incomplete (syntax errors)%s)" stderr)
+              (message "(clang-format: success%s)" stderr))))
       (delete-file temp-file)
       (when (buffer-name temp-buffer) (kill-buffer temp-buffer)))))