diff --git a/src/runtime/compact.cpp b/src/runtime/compact.cpp
index 344a034c10..0a4ff61895 100644
--- a/src/runtime/compact.cpp
+++ b/src/runtime/compact.cpp
@@ -435,6 +435,7 @@ void compacted_region::fix_mpz(object * o) {
     m._mp_d = reinterpret_cast<mp_limb_t *>(static_cast<char *>(m_begin) + reinterpret_cast<size_t>(m._mp_d) - reinterpret_cast<size_t>(m_base_addr));
     move(sizeof(mpz_object) + sizeof(mp_limb_t) * mpz_size(to_mpz(o)->m_value.m_val));
 #else
+    to_mpz(o)->m_value.m_digits = reinterpret_cast<mpn_digit*>(reinterpret_cast<char*>(o) + sizeof(mpz_object));
     move(sizeof(mpz_object) + sizeof(mpn_digit) * to_mpz(o)->m_value.m_size);
 #endif
 }