Remove some pointless micro-optimizations

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index da4b9c30b41c3e9d3f4ac17641e7a8fcb3f28233..0f2744d9e4ec42abd243b45527d2ff16dff0537a 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -234,7 +234,7 @@ namespace {
     {
         ei.kingRing[Them] = b | shift_bb<Down>(b);
         b &= ei.attackedBy[Us][PAWN];
-        ei.kingAttackersCount[Us] = b ? popcount(b) : 0;
+        ei.kingAttackersCount[Us] = popcount(b);
         ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
     }
     else
@@ -276,9 +276,7 @@ namespace {
         {
             ei.kingAttackersCount[Us]++;
             ei.kingAttackersWeight[Us] += KingAttackWeights[Pt];
-            bb = b & ei.attackedBy[Them][KING];
-            if (bb)
-                ei.kingAdjacentZoneAttacksCount[Us] += popcount(bb);
+            ei.kingAdjacentZoneAttacksCount[Us] += popcount(b & ei.attackedBy[Them][KING]);
         }
 
         if (Pt == QUEEN)
@@ -331,11 +329,7 @@ namespace {
         {
             // Bonus for aligning with enemy pawns on the same rank/file
             if (relative_rank(Us, s) >= RANK_5)
-            {
-                Bitboard alignedPawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
-                if (alignedPawns)
-                    score += RookOnPawn * popcount(alignedPawns);
-            }
+                score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]);
 
             // Bonus when on an open or semi-open file
             if (ei.pi->semiopen_file(Us, file_of(s)))
@@ -384,14 +378,17 @@ namespace {
     // Main king safety evaluation
     if (ei.kingAttackersCount[Them])
     {
-        // Find the attacked squares around the king which have no defenders
-        // apart from the king itself.
+        // Find the attacked squares which are defended only by the king...
         undefended =  ei.attackedBy[Them][ALL_PIECES]
                     & ei.attackedBy[Us][KING]
                     & ~(  ei.attackedBy[Us][PAWN]   | ei.attackedBy[Us][KNIGHT]
                         | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
                         | ei.attackedBy[Us][QUEEN]);
 
+        // ... and those which are not defended at all in the larger king ring
+        b =  ei.attackedBy[Them][ALL_PIECES] & ~ei.attackedBy[Us][ALL_PIECES]
+           & ei.kingRing[Us] & ~pos.pieces(Them);
+
         // Initialize the 'attackUnits' variable, which is used later on as an
         // index into the KingDanger[] array. The initial value is based on the
         // number and types of the enemy's attacking pieces, the number of
@@ -400,7 +397,7 @@ namespace {
         attackUnits =  std::min(72, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
                      +  9 * ei.kingAdjacentZoneAttacksCount[Them]
                      + 27 * popcount(undefended)
-                     + 11 * !!ei.pinnedPieces[Us]
+                     + 11 * (popcount(b) + !!ei.pinnedPieces[Us])
                      - 64 * !pos.count<QUEEN>(Them)
                      - mg_value(score) / 8;
 
@@ -414,8 +411,7 @@ namespace {
                 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]
                 | ei.attackedBy[Them][KING];
 
-            if (b)
-                attackUnits += QueenContactCheck * popcount(b);
+            attackUnits += QueenContactCheck * popcount(b);
         }
 
         // Analyse the enemy's safe distance checks for sliders and knights
@@ -511,9 +507,7 @@ namespace {
         while (b)
             score += Threat[Rook ][type_of(pos.piece_on(pop_lsb(&b)))];
 
-        b = weak & ~ei.attackedBy[Them][ALL_PIECES];
-        if (b)
-            score += Hanging * popcount(b);
+        score += Hanging * popcount(weak & ~ei.attackedBy[Them][ALL_PIECES]);
 
         b = weak & ei.attackedBy[Us][KING];
         if (b)
@@ -532,8 +526,7 @@ namespace {
        &  pos.pieces(Them)
        & ~ei.attackedBy[Us][PAWN];
 
-    if (b)
-        score += ThreatByPawnPush * popcount(b);
+    score += ThreatByPawnPush * popcount(b);
 
     if (DoTrace)
         Trace::add(THREAT, Us, score);
@@ -611,9 +604,6 @@ namespace {
                 mbonus += rr + r * 2, ebonus += rr + r * 2;
         } // rr != 0
 
-        if (pos.count<PAWN>(Us) < pos.count<PAWN>(Them))
-            ebonus += ebonus / 4;
-
         score += make_score(mbonus, ebonus) + PassedFile[file_of(s)];
     }