- // Avoid to do an expensive singular extension search on nodes where
- // such search have already been done in the past, so assume the last
- // singular extension search result is still valid.
- if ( !PvNode
- && depth < SingularExtensionDepth[PvNode] + 5 * OnePly
- && (ttx = TT.retrieve(pos.get_exclusion_key())) != NULL)
- {
- if (is_upper_bound(ttx->type()))
- ext = OnePly;
-
- singularExtensionNode = false;
- }
-