1 files changed, 3 insertions, 1 deletions
diff --git a/py/asmbase.c b/py/asmbase.c
index c941e917b..83a699cd4 100644
--- a/py/asmbase.c
+++ b/py/asmbase.c
@@ -47,8 +47,10 @@ void mp_asm_base_deinit(mp_asm_base_t *as, bool free_code) {
 
 void mp_asm_base_start_pass(mp_asm_base_t *as, int pass) {
     if (pass == MP_ASM_PASS_COMPUTE) {
-        // reset all labels
+        #ifndef NDEBUG
+        // With debugging enabled labels are checked for unique assignment
         memset(as->label_offsets, -1, as->max_num_labels * sizeof(size_t));
+        #endif
     } else if (pass == MP_ASM_PASS_EMIT) {
         // allocating executable RAM is platform specific
         MP_PLAT_ALLOC_EXEC(as->code_offset, (void**)&as->code_base, &as->code_size);