diff --git a/liboctave/util/oct-sort.cc b/liboctave/util/oct-sort.cc
index 3ebe936653..bb520d87d4 100644
--- a/liboctave/util/oct-sort.cc
+++ b/liboctave/util/oct-sort.cc
@@ -563,7 +563,7 @@ template <typename T>
 void
 octave_sort<T>::MergeState::getmemi (octave_idx_type need)
 {
-  if (m_ia && need <= m_alloced)
+  if (m_a && m_ia && need <= m_alloced)
     return;
 
   need = roundupsize (need);