Skip evaluate() call after a null move

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 03d05796ae69bd2df092183764604e9ac7f1d85d..075aa9b4422d01d490e2a1a25196e8befe7d6002 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1016,8 +1016,12 @@ split_point_start: // At split points actual search starts from here
           &&  depth >= Threads.min_split_depth()
           &&  bestValue < beta
           &&  Threads.available_slave_exists(thisThread))
+      {
           bestValue = Threads.split<FakeSplit>(pos, ss, alpha, beta, bestValue, &bestMove,
                                                depth, threatMove, moveCount, mp, NT);
+          if (bestValue >= beta)
+              break;
+      }
     }
 
     if (SpNode)
@@ -1150,6 +1154,11 @@ split_point_start: // At split points actual search starts from here
             if (ss->staticEval == VALUE_NONE || ss->evalMargin == VALUE_NONE) // Due to a race
                 ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);
         }
+        else if ((ss-1)->currentMove == MOVE_NULL)
+        {
+            ss->staticEval = bestValue = -(ss-1)->staticEval;
+            ss->evalMargin = VALUE_ZERO; // Hack, we really don't know the value
+        }
         else
             ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);