From: Michael Chaly <Vizvezdenec@gmail.com>
Date: Sat, 30 Jul 2022 23:04:23 +0000 (+0300)
Subject: Do more TT cutoffs in case of exact bound
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=582c88ee94c24b4352477ffacf8de2afc521bcce;p=stockfish

Do more TT cutoffs in case of exact bound

The idea is that these TT entries are considered move valuable in TT replacement scheme - they are always overwriting other entries. So it makes sence for them to produce more aggressive cutoffs.

passed STC
https://tests.stockfishchess.org/tests/view/62e4d407b383a712b1385410
LLR: 2.95 (-2.94,2.94) <0.00,2.50>
Total: 96632 W: 26045 L: 25659 D: 44928
Ptnml(0-2): 434, 10635, 25770, 11065, 412

passed LTC
https://tests.stockfishchess.org/tests/view/62e523e2b383a712b1386193
LLR: 2.94 (-2.94,2.94) <0.50,3.00>
Total: 77960 W: 21363 L: 20989 D: 35608
Ptnml(0-2): 190, 7591, 23009, 8035, 155

closes https://github.com/official-stockfish/Stockfish/pull/4114

bench 5820568
---

diff --git a/src/search.cpp b/src/search.cpp
index 96b1d0f1..004d061b 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -637,7 +637,7 @@ namespace {
     // At non-PV nodes we check for an early TT cutoff
     if (  !PvNode
         && ss->ttHit
-        && tte->depth() > depth - ((int)thisThread->id() & 0x1)
+        && tte->depth() > depth - ((int)thisThread->id() & 0x1) - (tte->bound() == BOUND_EXACT)
         && ttValue != VALUE_NONE // Possible in case of TT access race
         && (tte->bound() & (ttValue >= beta ? BOUND_LOWER : BOUND_UPPER)))
     {