diff --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -2249,6 +2249,9 @@
   if ((*this)->isArrayType())
     return Context.getBaseElementType(*this).isTrivialType(Context);
 
+  if ((*this)->isSizelessBuiltinType())
+    return true;
+
   // Return false for incomplete types after skipping any incomplete array
   // types which are expressly allowed by the standard and thus our API.
   if ((*this)->isIncompleteType())
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
@@ -516,6 +516,7 @@
   _Static_assert(!__is_literal(svint8_t), "");
   _Static_assert(__is_pod(svint8_t), "");
   _Static_assert(!__is_polymorphic(svint8_t), "");
+  _Static_assert(__is_trivial(svint8_t), "");
   _Static_assert(__is_object(svint8_t), "");
   _Static_assert(!__is_arithmetic(svint8_t), "");
   _Static_assert(!__is_floating_point(svint8_t), "");