diff --git a/src/math/gmp_desc.c b/src/math/gmp_desc.c
index 8709880..16c1d90 100644
--- a/src/math/gmp_desc.c
+++ b/src/math/gmp_desc.c
@@ -430,6 +430,7 @@ static int montgomery_reduce(void *a, void *b, void *c)
 /* clean up */
 static void montgomery_deinit(void *a)
 {
+  LTC_UNUSED_PARAM(a);
 }
 
 static int exptmod(void *a, void *b, void *c, void *d)