diff --git a/ChangeLog b/ChangeLog
index 101dbbfea4cda683e3968a1eb1b1475bc0e96397..c08f7d93ffdac3cf3fe1db32042b337dff957d5e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2014-07-02  Niels Möller  <nisse@lysator.liu.se>
+
+	* eccdata.c (ecc_dup): Use mpz_submul_ui, now available in
+	mini-gmp.
+
 2014-06-30  Niels Möller  <nisse@lysator.liu.se>
 
 	* camellia-absorb.c: Include <limits.h>, needed for correct use of
diff --git a/eccdata.c b/eccdata.c
index b8dc0011ecc1b7502ac4d911ae5335d232a60b08..13717bb13ca372cd93bc2aa3ff73b75498eaebe4 100644
--- a/eccdata.c
+++ b/eccdata.c
@@ -151,9 +151,7 @@ ecc_dup (const struct ecc_curve *ecc,
 
       /* x' = t^2 - 2 x */
       mpz_mul (x, t, t);
-      /* mpz_submul_ui (x, p->x, 2); not available in mini-gmp */
-      mpz_mul_ui (m, p->x, 2);
-      mpz_sub (x, x, m);
+      mpz_submul_ui (x, p->x, 2);
       mpz_mod (x, x, ecc->p);
 
       /* y' = (x - x') * t - y */