Simplify futility pruning formula

closes https://github.com/official-stockfish/Stockfish/pull/4848

No functional change

diff --git a/src/search.cpp b/src/search.cpp
index 9cef7e5f558225f5d6be62329f5ac47c2fe9c34a..24f0d9946f7ec598604ba8b60eb937437523847f 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -775,7 +775,7 @@ Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, boo
                - (ss - 1)->statScore / 321
              >= beta
         && eval >= beta && eval < 29462  // smaller than TB wins
-        && !(!ttCapture && ttMove))
+        && (!ttMove || ttCapture))
         return eval;
 
     // Step 9. Null move search with verification search (~35 Elo)