50-moves rule improvement for transposition table

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index f357db5e43cf8cc37399c0ab26d9a329a6cd5e95..dfc0e5bf79a9b1ef40064de18c85a603dad8ee26 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -716,7 +716,9 @@ namespace {
                 update_continuation_histories(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty);
             }
         }
-        return ttValue;
+
+        if (pos.rule50_count() < 90)
+            return ttValue;
     }
 
     // Step 5. Tablebases probe