diff --git a/library/bignum.c b/library/bignum.c
index bae0392..028ea69 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -1573,13 +1573,13 @@
     for( i = A->n; i > 0; i-- )
         if( A->p[i - 1] != 0 )
             break;
-    if( i == 0 && ( A->n == 0 || A->p[0] == 0 ) )
+    if( i == 0 )
         result_is_zero = 1;
 
     for( j = B->n; j > 0; j-- )
         if( B->p[j - 1] != 0 )
             break;
-    if( j == 0 && ( B->n == 0 || B->p[0] == 0 ) )
+    if( j == 0 )
         result_is_zero = 1;
 
     MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, i + j ) );