Index: lib/Tooling/ASTDiff/ASTDiff.cpp
===================================================================
--- lib/Tooling/ASTDiff/ASTDiff.cpp
+++ lib/Tooling/ASTDiff/ASTDiff.cpp
@@ -16,6 +16,7 @@
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Lex/Lexer.h"
 #include "llvm/ADT/PriorityQueue.h"
+#include "llvm/Support/CommandLine.h"
 
 #include <limits>
 #include <memory>
@@ -24,6 +25,12 @@
 using namespace llvm;
 using namespace clang;
 
+extern cl::OptionCategory ClangDiffCategory;
+static cl::opt<bool> StopAfterTopDown("stop-after-topdown",
+                                      cl::desc("Stops after top-down matching"),
+                                      cl::Optional, cl::init(false),
+                                      cl::cat(ClangDiffCategory));
+
 namespace clang {
 namespace diff {
 
@@ -891,7 +898,7 @@
 
 void ASTDiff::Impl::computeMapping() {
   TheMapping = matchTopDown();
-  if (Options.StopAfterTopDown)
+  if (StopAfterTopDown)
     return;
   matchBottomUp(TheMapping);
 }
Index: test/Tooling/clang-diff-topdown.cpp
===================================================================
--- test/Tooling/clang-diff-topdown.cpp
+++ test/Tooling/clang-diff-topdown.cpp
@@ -1,6 +1,6 @@
 // RUN: %clang_cc1 -E %s > %t.src.cpp
 // RUN: %clang_cc1 -E %s > %t.dst.cpp -DDEST
-// RUN: clang-diff -dump-matches -stop-after=topdown %t.src.cpp %t.dst.cpp -- -std=c++11 | FileCheck %s
+// RUN: clang-diff -dump-matches -stop-after-topdown %t.src.cpp %t.dst.cpp -- -std=c++11 | FileCheck %s
 //
 // Test the top-down matching of identical subtrees only.
 
Index: tools/clang-diff/ClangDiff.cpp
===================================================================
--- tools/clang-diff/ClangDiff.cpp
+++ tools/clang-diff/ClangDiff.cpp
@@ -21,7 +21,7 @@
 using namespace clang;
 using namespace clang::tooling;
 
-static cl::OptionCategory ClangDiffCategory("clang-diff options");
+cl::OptionCategory ClangDiffCategory("clang-diff options");
 
 static cl::opt<bool>
     ASTDump("ast-dump",
@@ -50,11 +50,6 @@
                                             cl::Optional,
                                             cl::cat(ClangDiffCategory));
 
-static cl::opt<std::string> StopAfter("stop-after",
-                                      cl::desc("<topdown|bottomup>"),
-                                      cl::Optional, cl::init(""),
-                                      cl::cat(ClangDiffCategory));
-
 static cl::opt<int> MaxSize("s", cl::desc("<maxsize>"), cl::Optional,
                             cl::init(-1), cl::cat(ClangDiffCategory));
 
@@ -442,14 +437,6 @@
   diff::ComparisonOptions Options;
   if (MaxSize != -1)
     Options.MaxSize = MaxSize;
-  if (!StopAfter.empty()) {
-    if (StopAfter == "topdown")
-      Options.StopAfterTopDown = true;
-    else if (StopAfter != "bottomup") {
-      llvm::errs() << "Error: Invalid argument for -stop-after\n";
-      return 1;
-    }
-  }
   diff::SyntaxTree SrcTree(Src->getASTContext());
   diff::SyntaxTree DstTree(Dst->getASTContext());
   diff::ASTDiff Diff(SrcTree, DstTree, Options);