diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -4348,6 +4348,7 @@
 
 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
   const Expr *SubExpr = E->getSubExpr();
+  assert(SubExpr && "SubExpr cannot be null");
   QualType ThrowType = SubExpr->getType();
   // The exception object lives on the stack and it's address is passed to the
   // runtime function.