From: Marco Costalba <mcostalba@gmail.com>
Date: Mon, 14 Jul 2014 13:15:07 +0000 (+0200)
Subject: Simplify evaluate_passed_pawns
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=896bd917f8e0dc5899b498fc3b62d3ee5e8fd9fe

Simplify evaluate_passed_pawns

From a suggestion by David Zar.

No functional change.
---

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 5a28b286..82bf950c 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -574,22 +574,18 @@ namespace {
             // If the pawn is free to advance, then increase the bonus
             if (pos.empty(blockSq))
             {
-                squaresToQueen = forward_bb(Us, s);
-
-                // 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 (    unlikely(forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
-                    && (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));
-
-                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 is a rook or queen attacking/defending the pawn from behind,
+                // consider all the squaresToQueen. Otherwise consider only the squares
+                // in the pawn's path attacked or occupied by the enemy.
+                defendedSquares = unsafeSquares = squaresToQueen = forward_bb(Us, s);
+
+                Bitboard bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
+
+                if (!(pos.pieces(Us) & bb))
+                    defendedSquares &= ei.attackedBy[Us][ALL_PIECES];
+
+                if (!(pos.pieces(Them) & bb))
+                    unsafeSquares &= ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them);
 
                 // If there aren't any enemy attacks, assign a big bonus. Otherwise
                 // assign a smaller bonus if the block square isn't attacked.