Futile pruning simplification

Remove CMH conditions in futile pruning.

STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 93520 W: 7165 L: 7138 D: 79217
Ptnml(0-2): 222, 5923, 34427, 5982, 206
https://tests.stockfishchess.org/tests/view/61083104e50a153c346ef8df

LTC:
LLR: 2.93 (-2.94,2.94) <-2.50,0.50>
Total: 59072 W: 1746 L: 1706 D: 55620
Ptnml(0-2): 13, 1562, 26353, 1588, 20
https://tests.stockfishchess.org/tests/view/610894f2e50a153c346ef913

closes https://github.com/official-stockfish/Stockfish/pull/3638

Bench: 5229673

diff --git a/src/search.cpp b/src/search.cpp
index 6275cdf283e3961fc5c4529b57b5788271434ea7..187f21694ef932d543eb474f8914719d9c2a46f1 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1023,11 +1023,7 @@ moves_loop: // When in check, search starts here
 
               // Futility pruning: parent node (~5 Elo)
               if (   !ss->inCheck
-                  && ss->staticEval + 174 + 157 * lmrDepth <= alpha
-                  &&  (*contHist[0])[movedPiece][to_sq(move)]
-                    + (*contHist[1])[movedPiece][to_sq(move)]
-                    + (*contHist[3])[movedPiece][to_sq(move)]
-                    + (*contHist[5])[movedPiece][to_sq(move)] / 3 < 28255)
+                  && ss->staticEval + 174 + 157 * lmrDepth <= alpha)
                   continue;
 
               // Prune moves with negative SEE (~20 Elo)