diff --git a/llvm/tools/llvm-diff/lib/DiffConsumer.h b/llvm/tools/llvm-diff/lib/DiffConsumer.h
--- a/llvm/tools/llvm-diff/lib/DiffConsumer.h
+++ b/llvm/tools/llvm-diff/lib/DiffConsumer.h
@@ -78,6 +78,7 @@
     DiffConsumer()
       : out(errs()), Differences(false), Indent(0) {}
 
+    void reset();
     bool hadDifferences() const;
     void enterContext(const Value *L, const Value *R) override;
     void exitContext() override;
diff --git a/llvm/tools/llvm-diff/lib/DiffConsumer.cpp b/llvm/tools/llvm-diff/lib/DiffConsumer.cpp
--- a/llvm/tools/llvm-diff/lib/DiffConsumer.cpp
+++ b/llvm/tools/llvm-diff/lib/DiffConsumer.cpp
@@ -134,6 +134,12 @@
   while (N--) out << ' ';
 }
 
+void DiffConsumer::reset() {
+  context.clear();
+  Differences = false;
+  Indent = 0;
+}
+
 bool DiffConsumer::hadDifferences() const {
   return Differences;
 }