Use staticEval in null prune condition

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index a36601bffc48f6965652694e886747c4a29a838a..97ab5918ae808090ca181aab078e35f15f8399d4 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -731,6 +731,7 @@ namespace {
     if (   !PvNode
         &&  depth >= 2 * ONE_PLY
         &&  eval >= beta
+        && (ss->staticEval >= beta || depth >= 12 * ONE_PLY)
         &&  pos.non_pawn_material(pos.side_to_move()))
     {
         ss->currentMove = MOVE_NULL;
@@ -815,7 +816,6 @@ namespace {
 
 moves_loop: // When in check search starts from here
 
-    Square prevSq = to_sq((ss-1)->currentMove);
     const CounterMoveStats* cmh  = (ss-1)->counterMoves;
     const CounterMoveStats* fmh  = (ss-2)->counterMoves;
     const CounterMoveStats* fmh2 = (ss-4)->counterMoves;
@@ -1106,10 +1106,10 @@ moves_loop: // When in check search starts from here
     // Bonus for prior countermove that caused the fail low
     else if (    depth >= 3 * ONE_PLY
              && !bestMove
-             && !inCheck
              && !pos.captured_piece_type()
              && is_ok((ss-1)->currentMove))
     {
+        Square prevSq = to_sq((ss-1)->currentMove);
         Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + 2 * depth / ONE_PLY - 2);
         if ((ss-2)->counterMoves)
             (ss-2)->counterMoves->update(pos.piece_on(prevSq), prevSq, bonus);