diff --git a/llvm/include/llvm/IR/PassInstrumentation.h b/llvm/include/llvm/IR/PassInstrumentation.h
index 031571599f9ad..33eda5a4222f1 100644
--- a/llvm/include/llvm/IR/PassInstrumentation.h
+++ b/llvm/include/llvm/IR/PassInstrumentation.h
@@ -164,7 +164,7 @@ class PassInstrumentationCallbacks {
 
   /// Add a class name to pass name mapping for use by pass instrumentation.
   LLVM_ABI void addClassToPassName(StringRef ClassName, StringRef PassName);
-  /// Get the pass name for a given pass class name.
+  /// Get the pass name for a given pass class name. Empty if no match found.
   LLVM_ABI StringRef getPassNameForClassName(StringRef ClassName);
 
 private:
diff --git a/llvm/lib/IR/PassInstrumentation.cpp b/llvm/lib/IR/PassInstrumentation.cpp
index 94ad124a6c770..70bbe8f6234b1 100644
--- a/llvm/lib/IR/PassInstrumentation.cpp
+++ b/llvm/lib/IR/PassInstrumentation.cpp
@@ -23,6 +23,7 @@ template struct LLVM_EXPORT_TEMPLATE Any::TypeId<const Loop *>;
 
 void PassInstrumentationCallbacks::addClassToPassName(StringRef ClassName,
                                                       StringRef PassName) {
+  assert(!PassName.empty() && "PassName can't be empty!");
   ClassToPassName.try_emplace(ClassName, PassName.str());
 }
 
@@ -33,7 +34,10 @@ PassInstrumentationCallbacks::getPassNameForClassName(StringRef ClassName) {
       Fn();
     ClassToPassNameCallbacks.clear();
   }
-  return ClassToPassName[ClassName];
+  auto PassNameIter = ClassToPassName.find(ClassName);
+  if (PassNameIter != ClassToPassName.end())
+    return PassNameIter->second;
+  return {};
 }
 
 AnalysisKey PassInstrumentationAnalysis::Key;