Micro-optimize perft

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 4ca9e9b8c0f834d8ccbcf91e3defdeae9fed24bd..f4f411c56d18f266f110d69ba5d4aa0b8c9707ad 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -155,21 +155,17 @@ void Search::init() {
 
 size_t Search::perft(Position& pos, Depth depth) {
 
-  // At the last ply just return the number of legal moves (leaf nodes)
-  if (depth == ONE_PLY)
-      return MoveList<LEGAL>(pos).size();
-
   StateInfo st;
   size_t cnt = 0;
   CheckInfo ci(pos);
+  const bool leaf = depth == 2 * ONE_PLY;
 
   for (MoveList<LEGAL> it(pos); *it; ++it)
   {
       pos.do_move(*it, st, ci, pos.move_gives_check(*it, ci));
-      cnt += perft(pos, depth - ONE_PLY);
+      cnt += leaf ? MoveList<LEGAL>(pos).size() : perft(pos, depth - ONE_PLY);
       pos.undo_move(*it);
   }
-
   return cnt;
 }
 
@@ -726,7 +722,6 @@ namespace {
         &&  depth >= 5 * ONE_PLY
         && !inCheck
         && !ss->skipNullMove
-        &&  excludedMove == MOVE_NONE
         &&  abs(beta) < VALUE_MATE_IN_MAX_PLY)
     {
         Value rbeta = beta + 200;
@@ -948,6 +943,10 @@ split_point_start: // At split points actual search starts from here
           &&  move != ss->killers[1])
       {
           ss->reduction = reduction<PvNode>(depth, moveCount);
+
+          if (!PvNode && cutNode)
+              ss->reduction += ONE_PLY;
+
           if (move == countermoves[0] || move == countermoves[1])
               ss->reduction = std::max(DEPTH_ZERO, ss->reduction-ONE_PLY);