diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7120,6 +7120,8 @@
   "cannot throw object of incomplete type %0">;
 def err_throw_incomplete_ptr : Error<
   "cannot throw pointer to object of incomplete type %0">;
+def err_throw_sizeless : Error<
+  "cannot throw object of sizeless type %0">;
 def warn_throw_underaligned_obj : Warning<
   "underaligned exception object thrown">,
   InGroup<UnderalignedExceptionObject>;
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -956,6 +956,11 @@
                             E->getSourceRange()))
       return true;
 
+    if (!isPointer && Ty->isSizelessType()) {
+      Diag(ThrowLoc, diag::err_throw_sizeless) << Ty << E->getSourceRange();
+      return true;
+    }
+
     if (RequireNonAbstractType(ThrowLoc, ExceptionObjectTy,
                                diag::err_throw_abstract_type, E))
       return true;
diff --git a/clang/test/SemaCXX/sizeless-1.cpp b/clang/test/SemaCXX/sizeless-1.cpp
--- a/clang/test/SemaCXX/sizeless-1.cpp
+++ b/clang/test/SemaCXX/sizeless-1.cpp
@@ -395,6 +395,9 @@
   local_int16 = static_cast<svint16_t>(local_int8); // expected-error {{static_cast from 'svint8_t' (aka '__SVInt8_t') to 'svint16_t' (aka '__SVInt16_t') is not allowed}}
   sel = static_cast<int>(local_int8);               // expected-error {{static_cast from 'svint8_t' (aka '__SVInt8_t') to 'int' is not allowed}}
 
+  throw local_int8; // expected-error {{cannot throw object of sizeless type 'svint8_t'}}
+  throw global_int8_ptr;
+
   local_int8.~__SVInt8_t(); // expected-error {{object expression of non-scalar type 'svint8_t' (aka '__SVInt8_t') cannot be used in a pseudo-destructor expression}}
 
   (void)svint8_t();