Reduce Position::pieces() overloads

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 4463b42aaed89e51aa561e81b30419b4abe62104..4187117b7df52d1150bc12594f9960a28d36d417 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1018,16 +1018,18 @@ moves_loop: // When in check, search starts here
               {
                   if (depth < 2 - capture)
                       continue;
-                  // don't prune move if a heavy enemy piece (KQR) is under attack after the exchanges
-                  Bitboard leftEnemies = (pos.pieces(~us, QUEEN, ROOK) | pos.pieces(~us, KING)) & occupied;
+                  // Don't prune the move if opp. King/Queen/Rook is attacked by a slider after the exchanges.
+                  // Since in see_ge we don't update occupied when the king recaptures, we also don't prune the
+                  // move when the opp. King gets a discovered slider attack DURING the exchanges.
+                  Bitboard leftEnemies = pos.pieces(~us, ROOK, QUEEN, KING) & occupied;
                   Bitboard attacks = 0;
                   occupied |= to_sq(move);
                   while (leftEnemies && !attacks)
                   {
                       Square sq = pop_lsb(leftEnemies);
-                      attacks |= pos.attackers_to(sq, occupied) & pos.pieces(us) & occupied;
-                      // exclude Queen/Rook(s) which were already threatened before SEE
-                      if (attacks && (sq != pos.square<KING>(~us) && (pos.attackers_to(sq, pos.pieces()) & pos.pieces(us))))
+                      attacks = pos.attackers_to(sq, occupied) & pos.pieces(us) & occupied;
+                      // Exclude Queen/Rook(s) which were already threatened before SEE
+                      if (attacks && sq != pos.square<KING>(~us) && (pos.attackers_to(sq, pos.pieces()) & pos.pieces(us)))
                           attacks = 0;
                   }
                   if (!attacks)