Fix zugzwang pruning issues

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 7029ae032ef8ba2703a7fa5080f4f319628fcf46..a9e76c452d9ae958603d7bc3efa7ca7dac8ce05c 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -97,8 +97,8 @@ namespace {
     Move best = MOVE_NONE;
   };
 
-  // EasyMoveManager structure is used to detect an 'easy move'. When the PV is
-  // stable across multiple search iterations, we can quickly return the best move.
+  // EasyMoveManager structure is used to detect an 'easy move'. When the PV is stable
+  // across multiple search iterations, we can quickly return the best move.
   struct EasyMoveManager {
 
     void clear() {
@@ -635,7 +635,7 @@ namespace {
             // Penalty for a quiet ttMove that fails low
             else if (!pos.capture_or_promotion(ttMove))
             {
-                Value penalty = -stat_bonus(depth + ONE_PLY);
+                Value penalty = -stat_bonus(depth);
                 thisThread->history.update(pos.side_to_move(), ttMove, penalty);
                 update_cm_stats(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty);
             }
@@ -898,6 +898,7 @@ moves_loop: // When in check search starts from here
 
       // Step 13. Pruning at shallow depth
       if (  !rootNode
+          && pos.non_pawn_material(pos.side_to_move())
           && bestValue > VALUE_MATED_IN_MAX_PLY)
       {
           if (   !captureOrPromotion
@@ -1125,10 +1126,11 @@ moves_loop: // When in check search starts from here
              && cm_ok)
         update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth));
 
-    tte->save(posKey, value_to_tt(bestValue, ss->ply),
-              bestValue >= beta ? BOUND_LOWER :
-              PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
-              depth, bestMove, ss->staticEval, TT.generation());
+    if(!excludedMove)
+        tte->save(posKey, value_to_tt(bestValue, ss->ply),
+                      bestValue >= beta ? BOUND_LOWER :
+                      PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
+                      depth, bestMove, ss->staticEval, TT.generation());
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);