diff --git a/libs/vkd3d-shader/dxil.c b/libs/vkd3d-shader/dxil.c
index 5bb05058..556902c2 100644
--- a/libs/vkd3d-shader/dxil.c
+++ b/libs/vkd3d-shader/dxil.c
@@ -6462,7 +6462,8 @@ static void sm6_parser_emit_cmpxchg(struct sm6_parser *sm6, const struct dxil_re
     uint64_t code;
 
     if (!(ptr = sm6_parser_get_value_by_ref(sm6, record, NULL, &i))
-            || !sm6_value_validate_is_pointer_to_i32(ptr, sm6))
+            || !sm6_value_validate_is_pointer_to_i32(ptr, sm6)
+            || !sm6_value_validate_is_backward_ref(ptr, sm6))
         return;
 
     if (ptr->u.reg.type != VKD3DSPR_GROUPSHAREDMEM)