Simplify Check Extension

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32704 W: 6146 L: 6045 D: 20513

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 146622 W: 19967 L: 20017 D: 106638

Bench: 8245662

diff --git a/src/search.cpp b/src/search.cpp
index 0b4125fcdd6ccf05279c848c1257eed89c042343..1db84c7e8522b12a488c9a4339e88f93fbad879e 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -873,9 +873,9 @@ moves_loop: // When in check search starts from here
                         && moveCount >= FutilityMoveCounts[improving][depth];
 
       // Step 12. Extend checks
                         && moveCount >= FutilityMoveCounts[improving][depth];
 
       // Step 12. Extend checks

-      if (   givesCheck
-          && (    moveCount == 1
-              || (!moveCountPruning && pos.see_sign(move) >= VALUE_ZERO)))
+      if (    givesCheck
+          && !moveCountPruning
+          &&  pos.see_sign(move) >= VALUE_ZERO)

           extension = ONE_PLY;
 
       // Singular extension search. If all moves but one fail low on a search of
           extension = ONE_PLY;
 
       // Singular extension search. If all moves but one fail low on a search of