diff --git a/clang/lib/ARCMigrate/ARCMT.cpp b/clang/lib/ARCMigrate/ARCMT.cpp
index c8052e3d79e1..260efae5bf6f 100644
--- a/clang/lib/ARCMigrate/ARCMT.cpp
+++ b/clang/lib/ARCMigrate/ARCMT.cpp
@@ -153,7 +153,7 @@ static bool HasARCRuntime(CompilerInvocation &origCI) {
       continue;
     if (!define.startswith(SimulatorVersionDefineName()))
       continue;
-    unsigned Major, Minor, Micro;
+    unsigned Major = 0, Minor = 0, Micro = 0;
     if (GetVersionFromSimulatorDefine(define, Major, Minor, Micro) &&
         Major < 10 && Minor < 100 && Micro < 100)
       return Major >= 5;
diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index 9344b6524751..4ff0a643d206 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -515,7 +515,7 @@ void Darwin::AddDeploymentTarget(DerivedArgList &Args) const {
            ie = Args.filtered_end(); it != ie; ++it) {
       StringRef define = (*it)->getValue(Args);
       if (define.startswith(SimulatorVersionDefineName())) {
-        unsigned Major, Minor, Micro;
+        unsigned Major = 0, Minor = 0, Micro = 0;
         if (GetVersionFromSimulatorDefine(define, Major, Minor, Micro) &&
             Major < 10 && Minor < 100 && Micro < 100) {
           ARCRuntimeForSimulator = Major < 5 ? ARCSimulator_NoARCRuntime