Index: clang-rename/USRFindingAction.h
===================================================================
--- clang-rename/USRFindingAction.h
+++ clang-rename/USRFindingAction.h
@@ -30,9 +30,9 @@
 
 struct USRFindingAction {
   USRFindingAction(ArrayRef<unsigned> SymbolOffsets,
-                   ArrayRef<std::string> QualifiedNames)
+                   ArrayRef<std::string> QualifiedNames, bool Force)
       : SymbolOffsets(SymbolOffsets), QualifiedNames(QualifiedNames),
-        ErrorOccurred(false) {}
+        ErrorOccurred(false), Force(Force) {}
   std::unique_ptr<ASTConsumer> newASTConsumer();
 
   ArrayRef<std::string> getUSRSpellings() { return SpellingNames; }
@@ -45,6 +45,7 @@
   std::vector<std::string> SpellingNames;
   std::vector<std::vector<std::string>> USRList;
   bool ErrorOccurred;
+  bool Force;
 };
 
 } // namespace rename
Index: clang-rename/USRFindingAction.cpp
===================================================================
--- clang-rename/USRFindingAction.cpp
+++ clang-rename/USRFindingAction.cpp
@@ -145,9 +145,9 @@
                            ArrayRef<std::string> QualifiedNames,
                            std::vector<std::string> &SpellingNames,
                            std::vector<std::vector<std::string>> &USRList,
-                           bool &ErrorOccurred)
+                           bool Force, bool &ErrorOccurred)
       : SymbolOffsets(SymbolOffsets), QualifiedNames(QualifiedNames),
-        SpellingNames(SpellingNames), USRList(USRList),
+        SpellingNames(SpellingNames), USRList(USRList), Force(Force),
         ErrorOccurred(ErrorOccurred) {}
 
 private:
@@ -182,6 +182,10 @@
         ErrorOccurred = true;
         return false;
       }
+
+      if (Force)
+        return true;
+
       unsigned CouldNotFindSymbolNamed = Engine.getCustomDiagID(
           DiagnosticsEngine::Error, "clang-rename could not find symbol %0");
       Engine.Report(CouldNotFindSymbolNamed) << QualifiedName;
@@ -218,12 +222,14 @@
   ArrayRef<std::string> QualifiedNames;
   std::vector<std::string> &SpellingNames;
   std::vector<std::vector<std::string>> &USRList;
+  bool Force;
   bool &ErrorOccurred;
 };
 
 std::unique_ptr<ASTConsumer> USRFindingAction::newASTConsumer() {
   return llvm::make_unique<NamedDeclFindingConsumer>(
-      SymbolOffsets, QualifiedNames, SpellingNames, USRList, ErrorOccurred);
+      SymbolOffsets, QualifiedNames, SpellingNames, USRList, Force,
+      ErrorOccurred);
 }
 
 } // namespace rename
Index: clang-rename/tool/ClangRename.cpp
===================================================================
--- clang-rename/tool/ClangRename.cpp
+++ clang-rename/tool/ClangRename.cpp
@@ -95,6 +95,9 @@
 static cl::opt<std::string>
     Input("input", cl::desc("YAML file to load oldname-newname pairs from."),
           cl::Optional, cl::cat(ClangRenameOptions));
+static cl::opt<bool> Force("force",
+                           cl::desc("Ignore nonexistent qualified names."),
+                           cl::cat(ClangRenameOptions));
 
 int main(int argc, const char **argv) {
   tooling::CommonOptionsParser OP(argc, argv, ClangRenameOptions);
@@ -157,7 +160,7 @@
 
   auto Files = OP.getSourcePathList();
   tooling::RefactoringTool Tool(OP.getCompilations(), Files);
-  rename::USRFindingAction FindingAction(SymbolOffsets, QualifiedNames);
+  rename::USRFindingAction FindingAction(SymbolOffsets, QualifiedNames, Force);
   Tool.run(tooling::newFrontendActionFactory(&FindingAction).get());
   const std::vector<std::vector<std::string>> &USRList =
       FindingAction.getUSRList();
@@ -173,6 +176,12 @@
     exit(1);
   }
 
+  if (Force && PrevNames.size() < NewNames.size()) {
+    // No matching PrevName for all NewNames. Without Force this is an error
+    // above already.
+    exit(0);
+  }
+
   // Perform the renaming.
   rename::RenamingAction RenameAction(NewNames, PrevNames, USRList,
                                       Tool.getReplacements(), PrintLocations);
Index: docs/clang-rename.rst
===================================================================
--- docs/clang-rename.rst
+++ docs/clang-rename.rst
@@ -124,6 +124,7 @@
     -export-fixes=<filename>   - YAML file to store suggested fixes in.
     -extra-arg=<string>        - Additional argument to append to the compiler command line
     -extra-arg-before=<string> - Additional argument to prepend to the compiler command line
+    -force                     - Ignore nonexistent qualified names.
     -i                         - Overwrite edited <file>s.
     -input=<string>            - YAML file to load oldname-newname pairs from.
     -new-name=<string>         - The new name to change the symbol to.
Index: test/clang-rename/InvalidQualifiedName.cpp
===================================================================
--- /dev/null
+++ test/clang-rename/InvalidQualifiedName.cpp
@@ -0,0 +1,4 @@
+struct S {
+};
+
+// RUN: clang-rename -force -qualified-name S2 -new-name=T %s --
Index: unittests/clang-rename/ClangRenameTest.h
===================================================================
--- unittests/clang-rename/ClangRenameTest.h
+++ unittests/clang-rename/ClangRenameTest.h
@@ -56,7 +56,7 @@
     Context.createInMemoryFile(HeaderName, HeaderContent);
     clang::FileID InputFileID = Context.createInMemoryFile(CCName, NewCode);
 
-    rename::USRFindingAction FindingAction({}, {OldName});
+    rename::USRFindingAction FindingAction({}, {OldName}, false);
     std::unique_ptr<tooling::FrontendActionFactory> USRFindingActionFactory =
         tooling::newFrontendActionFactory(&FindingAction);