diff --git a/lib/IR/DiagnosticInfo.cpp b/lib/IR/DiagnosticInfo.cpp
index b161d07ac98..45be100ae05 100644
--- a/lib/IR/DiagnosticInfo.cpp
+++ b/lib/IR/DiagnosticInfo.cpp
@@ -136,6 +136,7 @@ void DiagnosticInfoOptimizationBase::getLocation(StringRef *Filename,
                                                  unsigned *Line,
                                                  unsigned *Column) const {
   DILocation *L = getDebugLoc();
+  assert(L != nullptr && "debug location is invalid");
   *Filename = L->getFilename();
   *Line = L->getLine();
   *Column = L->getColumn();