Simplify away SEE verification

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 16122315032d2303ec48d4ae3ebf2c1b48d5b78a..1e82203a7775f7e4232f5b27f469667c6049b7c6 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -989,25 +989,9 @@ moves_loop: // When in check, search starts here
                    + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 7 < alpha)
                   continue;
 
-              Bitboard occupied;
               // SEE based pruning (~11 Elo)
-              if (!pos.see_ge(move, occupied, Value(-212) * depth))
-              {
-                  // Don't prune the move if opponent King/Queen/Rook gets a discovered attack during or after the exchanges
-                  Bitboard leftEnemies = pos.pieces(~us, KING, QUEEN, ROOK);
-                  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 (opponent King can't be in check when it's our turn)
-                      if (attacks && sq != pos.square<KING>(~us) && (pos.attackers_to(sq, pos.pieces()) & pos.pieces(us)))
-                          attacks = 0;
-                  }
-                  if (!attacks)
+              if (!pos.see_ge(move, Value(-205) * depth))
                       continue;
-              }
           }
           else
           {