Small micro-optimization in get_pawn_info()

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index f06b1283d418a529e8196150a5de85e8b934bd02..aa41c2cd8150b6baf86809d8e43832bacd7f2e25 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -193,6 +193,10 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) {
   Value mgValue[2] = {Value(0), Value(0)};
   Value egValue[2] = {Value(0), Value(0)};
 
+  // Calculate pawn attacks
+  pi->pawnAttacks[WHITE] = ((pos.pieces(PAWN, WHITE) << 9) & ~FileABB) | ((pos.pieces(PAWN, WHITE) << 7) & ~FileHBB);
+  pi->pawnAttacks[BLACK] = ((pos.pieces(PAWN, BLACK) >> 7) & ~FileABB) | ((pos.pieces(PAWN, BLACK) >> 9) & ~FileHBB);
+
   // Loop through the pawns for both colors
   for (Color us = WHITE; us <= BLACK; us++)
   {
@@ -299,12 +303,11 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) {
         // it cannot be backward. If can capture an enemy pawn or if
         // there are friendly pawns behind on neighboring files it cannot
         // be backward either.
+
         bool backward;
-        if (   passed
-            || isolated
-            || chain
-            || (pos.attacks_from<PAWN>(s, us) & theirPawns)
-            || (ourPawns & behind_bb(us, r) & neighboring_files_bb(f)))
+        if (   (passed | isolated | chain)
+            || (ourPawns & behind_bb(us, r) & neighboring_files_bb(f))
+            || (pos.attacks_from<PAWN>(s, us) & theirPawns))
             backward = false;
         else
         {