Fix reported DTZ for mate-in-1-ply positions

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 6377faf20d0881b0c13b8b63de39b41da65a6169..69a36cf5ee4659a43b80050925054d2e71b3c223 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -738,8 +738,7 @@ namespace {
     // pawn, or if it is undefended and attacked by an enemy piece.
     Bitboard safe =   SpaceMask
                    & ~pos.pieces(Us, PAWN)
-                   & ~attackedBy[Them][PAWN]
-                   & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]);
+                   & ~attackedBy[Them][PAWN];
 
     // Find all squares which are at most three squares behind some friendly pawn
     Bitboard behind = pos.pieces(Us, PAWN);