diff --git a/llvm/lib/Support/Signals.cpp b/llvm/lib/Support/Signals.cpp
--- a/llvm/lib/Support/Signals.cpp
+++ b/llvm/lib/Support/Signals.cpp
@@ -83,7 +83,7 @@
   std::atomic<Status> Flag;
 };
 static constexpr size_t MaxSignalHandlerCallbacks = 8;
-static CallbackAndCookie CallBacksToRun[MaxSignalHandlerCallbacks];
+static CallbackAndCookie CallBacksToRun[MaxSignalHandlerCallbacks]{};
 
 // Signal-safe.
 void sys::RunSignalHandlers() {