Skip futility pruning if ttMove has bad history

Passed STC: LLR: 2.96 (-2.94,2.94) <0.00,2.00> Total: 52416 W: 13465 L: 13128 D: 25823 Ptnml(0-2): 128, 6024, 13604, 6287, 165 https://tests.stockfishchess.org/tests/view/651fadd4ac577114367277bf Passed LTC: LLR: 2.94 (-2.94,2.94) <0.50,2.50> Total: 87348 W: 22234 L: 21818 D: 43296 Ptnml(0-2): 38, 9240, 24698, 9664, 34 https://tests.stockfishchess.org/tests/view/65201932ac57711436728218 closes #4825 bench: 1246560
official-stockfish · Oct 8, 2023 · 7a4de96 · 7a4de96
1 parent f7fbc68
commit 7a4de96
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diff --git a/AUTHORS b/AUTHORS
@@ -210,6 +210,7 @@ Steinar Gunderson (sesse)
 Stéphane Nicolet (snicolet)
 Stephen Touset (stouset)
 Syine Mineta (MinetaS)
+Taras Vuk (TarasVuk)
 Thanar2
 thaspel
 theo77186

diff --git a/src/search.cpp b/src/search.cpp
@@ -780,7 +780,10 @@ namespace {
         &&  depth < 9
         &&  eval - futility_margin(depth, cutNode && !ss->ttHit, improving) - (ss-1)->statScore / 306 >= beta
         &&  eval >= beta
-        &&  eval < 24923) // smaller than TB wins
+        &&  eval < 24923 // smaller than TB wins
+        && !(  !ttCapture
+             && ttMove
+             && thisThread->mainHistory[us][from_to(ttMove)] < 989))
         return eval;
 
     // Step 9. Null move search with verification search (~35 Elo)