diff --git a/llvm/lib/IR/Type.cpp b/llvm/lib/IR/Type.cpp
--- a/llvm/lib/IR/Type.cpp
+++ b/llvm/lib/IR/Type.cpp
@@ -217,8 +217,11 @@
   if (auto *VTy = dyn_cast<VectorType>(this))
     return VTy->getElementType()->isSized(Visited);
 
-  if (auto *TTy = dyn_cast<TargetExtType>(this))
-    return TTy->getLayoutType()->isSized(Visited);
+  if (auto *TTy = dyn_cast<TargetExtType>(this)) {
+    if (Type *LTy = TTy->getLayoutType())
+      return LTy->isSized(Visited);
+    return false;
+  }
 
   return cast<StructType>(this)->isSized(Visited);
 }