Simplify "fail high upon reduction" in null search

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 945fb4e44299dafab044810ac09ae72d4e6c0142..c5af2f89524e5f9c04b89bb5c1780d8caa105911 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -530,7 +530,7 @@ Value do_evaluate(const Position& pos, Value& margin) {
 
         // Bishop and knight outposts squares
         if (    (Piece == BISHOP || Piece == KNIGHT)
-            && !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s)))
+            && !(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
             score += evaluate_outposts<Piece, Us>(pos, ei, s);
 
         if (  (Piece == ROOK || Piece == QUEEN)
@@ -821,7 +821,8 @@ Value do_evaluate(const Position& pos, Value& margin) {
                 // 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
                 // the squares in the pawn's path attacked or occupied by the enemy.
-                if (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from<ROOK>(s))
+                if (   (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN)) // Unlikely
+                    && (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
                     unsafeSquares = squaresToQueen;
                 else
                     unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
@@ -989,7 +990,7 @@ Value do_evaluate(const Position& pos, Value& margin) {
             // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
             if (!opposed)
             {
-                b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
+                b2 = supporters & in_front_bb(winnerSide, rank_of(blockSq + pawn_push(winnerSide)));
 
                 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
                 {
@@ -999,7 +1000,7 @@ Value do_evaluate(const Position& pos, Value& margin) {
             }
 
             // Check pawns that can be sacrificed against the blocking pawn
-            b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
+            b2 = pawn_attack_span(winnerSide, blockSq) & candidates & ~(1ULL << s);
 
             while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
             {