X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=b33d2e976a8daef8584639ea827b6547d63e342d;hp=a73910a7b8be82c91d3b0c6e287ebea783954af6;hb=4b9e33854180ddba931a1f61368e2991a55a9651;hpb=a0cf424cfc7344d95c60a6f5862eb02cf75c773a;ds=sidebyside

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index a73910a7..b33d2e97 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -826,7 +826,6 @@ Value do_evaluate(const Position& pos, Value& margin) {
             if (pos.is_empty(blockSq))
             {
                 squaresToQueen = forward_bb(Us, s);
-                defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
 
                 // If there is an enemy rook or queen attacking the pawn from behind,
                 // add all X-ray attacks by the rook or queen. Otherwise consider only
@@ -837,6 +836,12 @@ Value do_evaluate(const Position& pos, Value& margin) {
                 else
                     unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
 
+                if (    unlikely(forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN))
+                    && (forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
+                    defendedSquares = squaresToQueen;
+                else
+                    defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
+
                 // If there aren't enemy attacks huge bonus, a bit smaller if at
                 // least block square is not attacked, otherwise smallest bonus.
                 int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3;