Microptimize MoveList loop

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index daed19135359406ddfde08e3c5f825b5e918803c..8ba5b41af8be9cf182a02650dc9457d7fa515239 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -86,8 +86,9 @@ namespace {
   TimeManager TimeMgr;
   int BestMoveChanges;
   Value DrawValue[COLOR_NB];
-  History Hist;
-  Gains Gain;
+  HistoryStats History;
+  GainsStats Gains;
+  CountermovesStats Countermoves;
 
   template <NodeType NT>
   Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
@@ -162,11 +163,11 @@ size_t Search::perft(Position& pos, Depth depth) {
   size_t cnt = 0;
   CheckInfo ci(pos);
 
-  for (MoveList<LEGAL> ml(pos); !ml.end(); ++ml)
+  for (MoveList<LEGAL> it(pos); *it; ++it)
   {
-      pos.do_move(ml.move(), st, ci, pos.move_gives_check(ml.move(), ci));
+      pos.do_move(*it, st, ci, pos.move_gives_check(*it, ci));
       cnt += perft(pos, depth - ONE_PLY);
-      pos.undo_move(ml.move());
+      pos.undo_move(*it);
   }
 
   return cnt;
@@ -303,8 +304,9 @@ namespace {
     bestValue = delta = -VALUE_INFINITE;
     ss->currentMove = MOVE_NULL; // Hack to skip update gains
     TT.new_search();
-    Hist.clear();
-    Gain.clear();
+    History.clear();
+    Gains.clear();
+    Countermoves.clear();
 
     PVSize = Options["MultiPV"];
     Skill skill(Options["Skill Level"]);
@@ -621,7 +623,7 @@ namespace {
         &&  type_of(move) == NORMAL)
     {
         Square to = to_sq(move);
-        Gain.update(pos.piece_on(to), to, -(ss-1)->staticEval - ss->staticEval);
+        Gains.update(pos.piece_on(to), to, -(ss-1)->staticEval - ss->staticEval);
     }
 
     // Step 6. Razoring (is omitted in PV nodes)
@@ -732,7 +734,7 @@ namespace {
         assert((ss-1)->currentMove != MOVE_NONE);
         assert((ss-1)->currentMove != MOVE_NULL);
 
-        MovePicker mp(pos, ttMove, Hist, pos.captured_piece_type());
+        MovePicker mp(pos, ttMove, History, pos.captured_piece_type());
         CheckInfo ci(pos);
 
         while ((move = mp.next_move<false>()) != MOVE_NONE)
@@ -764,7 +766,11 @@ namespace {
 
 split_point_start: // At split points actual search starts from here
 
-    MovePicker mp(pos, ttMove, depth, Hist, ss, PvNode ? -VALUE_INFINITE : beta);
+    Square prevMoveSq = to_sq((ss-1)->currentMove);
+    Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first,
+                            Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second };
+
+    MovePicker mp(pos, ttMove, depth, History, countermoves, ss, PvNode ? -VALUE_INFINITE : beta);
     CheckInfo ci(pos);
     value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
     singularExtensionNode =   !RootNode
@@ -882,7 +888,7 @@ split_point_start: // At split points actual search starts from here
           // but fixing this made program slightly weaker.
           Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
           futilityValue =  ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
-                         + Gain[pos.piece_moved(move)][to_sq(move)];
+                         + Gains[pos.piece_moved(move)][to_sq(move)];
 
           if (futilityValue < beta)
           {
@@ -940,6 +946,9 @@ split_point_start: // At split points actual search starts from here
           &&  move != ss->killers[1])
       {
           ss->reduction = reduction<PvNode>(depth, moveCount);
+          if (move == countermoves[0] || move == countermoves[1])
+              ss->reduction = std::max(DEPTH_ZERO, ss->reduction-ONE_PLY);
+
           Depth d = std::max(newDepth - ss->reduction, ONE_PLY);
           if (SpNode)
               alpha = splitPoint->alpha;
@@ -1089,13 +1098,15 @@ split_point_start: // At split points actual search starts from here
 
             // Increase history value of the cut-off move
             Value bonus = Value(int(depth) * int(depth));
-            Hist.update(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
+            History.update(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
+            if (is_ok((ss-1)->currentMove))
+                Countermoves.update(pos.piece_on(prevMoveSq), prevMoveSq, bestMove);
 
             // Decrease history of all the other played non-capture moves
             for (int i = 0; i < playedMoveCount - 1; i++)
             {
                 Move m = movesSearched[i];
-                Hist.update(pos.piece_moved(m), to_sq(m), -bonus);
+                History.update(pos.piece_moved(m), to_sq(m), -bonus);
             }
         }
     }
@@ -1208,7 +1219,7 @@ split_point_start: // At split points actual search starts from here
     // to search the moves. Because the depth is <= 0 here, only captures,
     // queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
     // be generated.
-    MovePicker mp(pos, ttMove, depth, Hist, to_sq((ss-1)->currentMove));
+    MovePicker mp(pos, ttMove, depth, History, to_sq((ss-1)->currentMove));
     CheckInfo ci(pos);
 
     // Loop through the moves until no moves remain or a beta cutoff occurs