diff --git a/library/bignum.c b/library/bignum.c
index dfcb81938..06445cc11 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -953,7 +953,7 @@ int mbedtls_mpi_cmp_mpi_ct( const mbedtls_mpi *X, const mbedtls_mpi *Y,
         int *ret )
 {
     size_t i;
-    unsigned int cond, done;
+    unsigned int cond, done, sign_X, sign_Y;
 
     if( X->n != Y->n )
         return MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
@@ -970,8 +970,8 @@ int mbedtls_mpi_cmp_mpi_ct( const mbedtls_mpi *X, const mbedtls_mpi *Y,
      *     done = 1;
      * }
      */
-    unsigned int sign_X = X->s;
-    unsigned int sign_Y = Y->s;
+    sign_X = X->s;
+    sign_Y = Y->s;
     cond = ( ( sign_X ^ sign_Y ) >> ( sizeof( unsigned int ) * 8 - 1 ) );
     *ret = cond * X->s;
     done = cond;