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Remove killer move #324

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Remove killer move #324

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12 changes: 2 additions & 10 deletions src/movepick.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -59,15 +59,7 @@ Move MovePicker::next() {
goto emit_bad_noisy;
}

m_stage = Stage::EmitKiller;

[[fallthrough]];

case Stage::EmitKiller:
m_stage = Stage::ScoreQuiet;
if (m_tt_move != m_killer && m_killer != Move::none() && m_movegen.is_legal(m_killer)) {
return m_killer;
}

[[fallthrough]];

Expand All @@ -81,7 +73,7 @@ Move MovePicker::next() {
case Stage::EmitQuiet:
while (m_current_index < m_quiet.size()) {
auto [curr, score] = pick_next(m_quiet);
if (curr != m_tt_move && curr != m_killer) {
if (curr != m_tt_move) {
return curr;
}
}
Expand All @@ -95,7 +87,7 @@ Move MovePicker::next() {
case Stage::EmitBadNoisy:
while (m_current_index < m_bad_noisy.size()) {
Move curr = m_bad_noisy[m_current_index++];
if (curr != m_tt_move && curr != m_killer) {
if (curr != m_tt_move) {
return curr;
}
}
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3 changes: 0 additions & 3 deletions src/movepick.hpp
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Expand Up @@ -19,7 +19,6 @@
m_history(history),
m_movegen(pos),
m_tt_move(tt_move),
m_killer(ss->killer),
m_ply(ply),
m_stack(ss) {
}
Expand All @@ -29,7 +28,6 @@
GenerateMoves,
ScoreNoisy,
EmitGoodNoisy,
EmitKiller,
ScoreQuiet,
EmitQuiet,
EmitBadNoisy,
Expand All @@ -53,7 +51,7 @@
std::pair<Move, i32> pick_next(MoveList& moves);
void score_moves(MoveList& moves);

i32 score_move(Move move) const;

Check warning on line 54 in src/movepick.hpp

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GitHub Actions / Linter / cpp-linter

src/movepick.hpp:54:5 [modernize-use-nodiscard] 

function 'score_move' should be marked [[nodiscard]]

Stage m_stage = Stage::EmitTTMove;

Expand All @@ -68,7 +66,6 @@
std::array<i32, 256> m_scores;

Move m_tt_move;
Move m_killer;
i32 m_ply;
Search::Stack* m_stack;
};
Expand Down
4 changes: 0 additions & 4 deletions src/search.cpp
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Expand Up @@ -508,8 +508,6 @@ Value Worker::search(
i32 alpha_raises = 0;
Value non_pawn_material = -1;

// Clear child's killer move.
(ss + 1)->killer = Move::none();
// Clear child's fail high count
(ss + 1)->fail_high_count = 0;

Expand Down Expand Up @@ -748,8 +746,6 @@ Value Worker::search(
i32 bonus_depth = depth + (best_value >= beta + 100);
const i32 bonus = stat_bonus(bonus_depth);
if (quiet_move(best_move)) {
ss->killer = best_move;

m_td.history.update_quiet_stats(pos, best_move, ply, ss, bonus);
for (Move quiet : quiets_played) {
m_td.history.update_quiet_stats(pos, quiet, ply, ss, -bonus);
Expand Down
5 changes: 2 additions & 3 deletions src/search.hpp
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Expand Up @@ -60,9 +60,8 @@ struct PV {
};

struct Stack {
Value static_eval = 0;
Move killer = Move::none();
Move excluded_move;
Value static_eval = 0;
Move excluded_move = Move::none();
ContHistEntry* cont_hist_entry = nullptr;
i32 fail_high_count = 0;
PV pv;
Expand Down
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