Reintroduce late irreversible move extension

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 886ed52ca0bbf65f3fca476d4bffe12a650f44d2..8be96e298ec17aa2936bb47c1150d79a02d518c2 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1134,6 +1134,12 @@ moves_loop: // When in check, search starts from here
       // Castling extension
       if (type_of(move) == CASTLING)
           extension = 1;
       // Castling extension
       if (type_of(move) == CASTLING)
           extension = 1;

+         
+      // Late irreversible move extension
+      if (   move == ttMove
+          && pos.rule50_count() > 80
+          && (captureOrPromotion || type_of(movedPiece) == PAWN))
+          extension = 2;

 
       // Add extension to new depth
       newDepth += extension;
 
       // Add extension to new depth
       newDepth += extension;