diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 242eb85..ec23830 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -129,9 +129,6 @@
     (void) hash_alg;
     return global_data.drivers_initialized;
 }
-#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR) ||       \
-    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_PUBLIC_KEY) ||     \
-    defined(PSA_WANT_KEY_TYPE_DH_KEY_PAIR)
 static int psa_is_dh_key_size_valid(size_t bits)
 {
     if (bits != 2048 && bits != 3072 && bits != 4096 &&
@@ -141,9 +138,6 @@
 
     return 1;
 }
-#endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR ||
-          MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_PUBLIC_KEY ||
-          PSA_WANT_KEY_TYPE_DH_KEY_PAIR */
 
 psa_status_t mbedtls_to_psa_error(int ret)
 {
@@ -1450,6 +1444,11 @@
 #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR) ||
         * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_PUBLIC_KEY) */
     } else {
+        (void) key_buffer;
+        (void) key_buffer_size;
+        (void) data;
+        (void) data_size;
+        (void) data_length;
         return PSA_ERROR_NOT_SUPPORTED;
     }
 }