Do not sort negative non captures at low depth

Speedup of the whole 3 patch series is of 2,5% !!

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 8f3f65b..61e5527 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -56,7 +56,7 @@ namespace {
 /// move ordering is at the current node.
 
 MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
-                       SearchStack* ss, Value beta) : pos(p), H(h) {
+                       SearchStack* ss, Value beta) : pos(p), H(h), depth(d) {
   captureThreshold = 0;
   badCaptures = moves + MAX_MOVES;
 
@@ -162,7 +162,8 @@ void MovePicker::go_next_phase() {
   case PH_NONCAPTURES_2:
       curMove = lastMove;
       lastMove = lastNonCapture;
-      insertion_sort<MoveStack>(curMove, lastMove);
+      if (depth >= 3 * ONE_PLY)
+          insertion_sort<MoveStack>(curMove, lastMove);
       return;
 
   case PH_BAD_CAPTURES:

diff --git a/src/movepick.h b/src/movepick.h
index c4d665a..d0ced04 100644 (file)
--- a/src/movepick.h
+++ b/src/movepick.h
@@ -53,6 +53,7 @@ private:
 
   const Position& pos;
   const History& H;
+  Depth depth;
   Move ttMove;
   MoveStack killers[2];
   int captureThreshold, phase;