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Small tt verify simplification

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Also fix probcut comment

Passed non-regression STC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 69728 W: 18080 L: 17909 D: 33739
Ptnml(0-2): 161, 7157, 20044, 7354, 148
https://tests.stockfishchess.org/tests/view/68324b116ec7634154f9b478

closes https://github.com/official-stockfish/Stockfish/pull/6094

No functional change
This commit is contained in:
Daniel Monroe
2025-05-25 12:58:01 -07:00
committed by Joost VandeVondele
parent 9b79b75c9b
commit dfa176fc7e
2 changed files with 7 additions and 15 deletions
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14
src/search.cpp
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@@ -701,18 +701,12 @@ Value Search::Worker::search(
do_move(pos, ttData.move, st);
Key nextPosKey = pos.key();
auto [ttHitNext, ttDataNext, ttWriterNext] = tt.probe(nextPosKey);
ttDataNext.value =
ttHitNext ? value_from_tt(ttDataNext.value, ss->ply + 1, pos.rule50_count())
: VALUE_NONE;
undo_move(pos, ttData.move);
// Check that the ttValue after the tt move would also trigger a cutoff
if (!is_valid(ttDataNext.value))
return ttData.value;
if (ttData.value >= beta && -ttDataNext.value >= beta)
return ttData.value;
if (ttData.value <= alpha && -ttDataNext.value <= alpha)
if ((ttData.value >= beta) == (-ttDataNext.value >= beta))
return ttData.value;
}
else
@@ -916,9 +910,7 @@ Value Search::Worker::search(
if (depth >= 3
&& !is_decisive(beta)
// If value from transposition table is lower than probCutBeta, don't attempt
// probCut there and in further interactions with transposition table cutoff
// depth is set to depth - 3 because probCut search has depth set to depth - 4
// but we also do a move before it. So effective depth is equal to depth - 3.
// probCut there
&& !(is_valid(ttData.value) && ttData.value < probCutBeta))
{
assert(probCutBeta < VALUE_INFINITE && probCutBeta > beta);