Don't clear EasyMove in search()

EasyMove is cleared after every iteration of the
search if the 3rd move in the PV of the main thread
changes from the previous iteration. Therefore,
clearing EasyMove during a search iteration may be
excessive. The tests show that this is indeed unnecessary.
In the new version the EasyMove variable is used only in
the Thread::search function.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 47719 W: 8438 L: 8362 D: 30919

LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 122841 W: 15448 L: 15457 D: 91936

bench: 5468995

diff --git a/src/search.cpp b/src/search.cpp
index 75d388b945ea2573b211f6078ab7006c006ac4a3..3387091363212dc40b0d88c17e210cdd44d5db8b 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1074,13 +1074,6 @@ moves_loop: // When in check search starts from here
 
           if (value > alpha)
           {
 
           if (value > alpha)
           {

-              // If there is an easy move for this position, clear it if unstable
-              if (    PvNode
-                  &&  thisThread == Threads.main()
-                  &&  EasyMove.get(pos.key())
-                  && (move != EasyMove.get(pos.key()) || moveCount > 1))
-                  EasyMove.clear();
-

               bestMove = move;
 
               if (PvNode && !rootNode) // Update pv even in fail-high case
               bestMove = move;
 
               if (PvNode && !rootNode) // Update pv even in fail-high case