diff --git a/common/mbedtls/bignum.c b/common/mbedtls/bignum.c
index 9b7bcdd1c..200ad7ca0 100644
--- a/common/mbedtls/bignum.c
+++ b/common/mbedtls/bignum.c
@@ -1442,6 +1442,7 @@ __attribute__((noinline))
 #endif
 void mpi_mul_hlp(size_t i, mbedtls_mpi_uint *s, mbedtls_mpi_uint *d, mbedtls_mpi_uint b) {
     mbedtls_mpi_uint c = 0, t = 0;
+    (void)t;
 
 #if defined(MULADDC_HUIT)
     for (; i >= 8; i -= 8) {