Simplify check extension

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 99c2b09f9ef42b4032c95864e7f4e0e497147ec5..fd833b812d9935c5fcdec4ab105b8cce5a689034 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1130,6 +1130,8 @@ moves_loop: // When in check, search starts from here
           {
               extension = 1;
               singularQuietLMR = !ttCapture;
+              if (!PvNode && value < singularBeta - 140)
+                  extension = 2;
           }
 
           // Multi-cut pruning
@@ -1153,11 +1155,6 @@ moves_loop: // When in check, search starts from here
           }
       }
 
-      // Check extension (~2 Elo)
-      else if (    givesCheck
-               && (pos.is_discovered_check_on_king(~us, move) || pos.see_ge(move)))
-          extension = 1;
-
       // Add extension to new depth
       newDepth += extension;