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Remove unused code from the post NNUE accumulator merge

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After merging the HalfKA and Threats accumulators (7c7fe322) and the
subsequent removal of the double-incremental/fused update, a number of
NNUE helpers and fields became unreachable. Each was verified to have
zero callers/readers across the source tree:

- FusedUpdateData logic in FullThreats: the fused-update branch of
  append_changed_indices and the FusedUpdateData parameter are unused;
  the accumulator update no longer passes fused data.
- FullThreats::requires_refresh: never called. The live king-bucket
  refresh check is HalfKAv2_hm::requires_refresh (PSQFeatureSet), used
  in nnue_accumulator.
- HalfKAv2_hm::append_active_indices: never called. The live
  active-index builder is FullThreats::append_active_indices
  (ThreatFeatureSet).
- DirtyThreats::us, prevKsq and ksq: written in do_move but only read by
  the now-removed FullThreats::requires_refresh. Removing them also
  drops three stores from the do_move path.
- Unused feature Name constants and the unused FtOneVal / HiddenMaxVal
  constants in nnue_common.h.
- Two stale feature-header banner comments.

closes https://github.com/official-stockfish/Stockfish/pull/6898

No functional change
This commit is contained in:
zungur
2026-06-14 09:58:13 +02:00
committed by Disservin
parent 6e4e03fd28
commit ed8e35d759
8 changed files with 12 additions and 93 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/nnue/features/full_threats.cpp
-36
View File
@@ -275,8 +275,6 @@ void FullThreats::append_changed_indices(Color perspective,
const DiffType& diff,
IndexList& removed,
IndexList& added,
FusedUpdateData* fusedData,
bool first,
const ThreatWeightType* prefetchBase,
IndexType prefetchStride) {
@@ -288,36 +286,6 @@ void FullThreats::append_changed_indices(Color perspective,
auto to = dirty.threatened_sq();
auto add = dirty.add();
if (fusedData)
{
if (from == fusedData->dp2removed)
{
if (add)
{
if (first)
{
fusedData->dp2removedOriginBoard |= to;
continue;
}
}
else if (fusedData->dp2removedOriginBoard & to)
continue;
}
else if (to != SQ_NONE && to == fusedData->dp2removed)
{
if (add)
{
if (first)
{
fusedData->dp2removedTargetBoard |= from;
continue;
}
}
else if (fusedData->dp2removedTargetBoard & from)
continue;
}
}
auto& insert = add ? added : removed;
const IndexType index = make_index(perspective, attacker, from, to, attacked, ksq);
@@ -328,8 +296,4 @@ void FullThreats::append_changed_indices(Color perspective,
}
}
bool FullThreats::requires_refresh(const DiffType& diff, Color perspective) {
return perspective == diff.us && (i8(diff.ksq) & 0b100) != (i8(diff.prevKsq) & 0b100);
}
} // namespace Stockfish::Eval::NNUE::Features
src/nnue/features/full_threats.h
+1 -17
View File
@@ -13,7 +13,7 @@
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//Definition of input features Simplified_Threats of NNUE evaluation function
//Definition of input features Full_Threats of NNUE evaluation function
#ifndef NNUE_FEATURES_FULL_THREATS_INCLUDED
#define NNUE_FEATURES_FULL_THREATS_INCLUDED
@@ -34,9 +34,6 @@ static constexpr int numValidTargets[PIECE_NB] = {0, 6, 10, 8, 8, 10, 0, 0,
class FullThreats {
public:
// Feature name
static constexpr const char* Name = "Full_Threats(Friend)";
// Hash value embedded in the evaluation file
static constexpr u32 HashValue = 0x8f234cb8u;
@@ -66,13 +63,6 @@ class FullThreats {
};
// clang-format on
struct FusedUpdateData {
Bitboard dp2removedOriginBoard = 0;
Bitboard dp2removedTargetBoard = 0;
Square dp2removed;
};
// Maximum number of simultaneously active features.
static constexpr IndexType MaxActiveDimensions = 128;
using IndexList = ValueList<IndexType, MaxActiveDimensions>;
@@ -90,14 +80,8 @@ class FullThreats {
const DiffType& diff,
IndexList& removed,
IndexList& added,
FusedUpdateData* fd = nullptr,
bool first = false,
const ThreatWeightType* prefetchBase = nullptr,
IndexType prefetchStride = 0);
// Returns whether the change stored in this DirtyPiece means
// that a full accumulator refresh is required.
static bool requires_refresh(const DiffType& diff, Color perspective);
};
} // namespace Stockfish::Eval::NNUE::Features
src/nnue/features/half_ka_v2_hm.cpp
+4 -14
View File
@@ -20,11 +20,13 @@
#include "half_ka_v2_hm.h"
#include "../../bitboard.h"
#include "../../position.h"
#include "../../types.h"
#include "../nnue_common.h"
#if defined(USE_AVX512ICL)
#include "../../bitboard.h"
#endif
namespace Stockfish::Eval::NNUE::Features {
#if defined(USE_AVX512ICL)
@@ -91,18 +93,6 @@ IndexType HalfKAv2_hm::make_index(Color perspective, Square s, Piece pc, Square
+ KingBuckets[int(ksq) ^ flip];
}
// Get a list of indices for active features
void HalfKAv2_hm::append_active_indices(Color perspective, const Position& pos, IndexList& active) {
Square ksq = pos.square<KING>(perspective);
Bitboard bb = pos.pieces();
while (bb)
{
Square s = pop_lsb(bb);
active.push_back(make_index(perspective, s, pos.piece_on(s), ksq));
}
}
// Get a list of indices for recently changed features
void HalfKAv2_hm::append_changed_indices(
src/nnue/features/half_ka_v2_hm.h
+1 -12
View File
@@ -16,7 +16,7 @@
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//Definition of input features HalfKP of NNUE evaluation function
//Definition of input features HalfKAv2_hm of NNUE evaluation function
#ifndef NNUE_FEATURES_HALF_KA_V2_HM_H_INCLUDED
#define NNUE_FEATURES_HALF_KA_V2_HM_H_INCLUDED
@@ -25,10 +25,6 @@
#include "../../types.h"
#include "../nnue_common.h"
namespace Stockfish {
class Position;
}
namespace Stockfish::Eval::NNUE::Features {
// Feature HalfKAv2_hm: Combination of the position of own king and the
@@ -61,9 +57,6 @@ class HalfKAv2_hm {
PS_NONE, PS_W_PAWN, PS_W_KNIGHT, PS_W_BISHOP, PS_W_ROOK, PS_W_QUEEN, PS_KING, PS_NONE}};
public:
// Feature name
static constexpr const char* Name = "HalfKAv2_hm(Friend)";
// Hash value embedded in the evaluation file
static constexpr u32 HashValue = 0x7f234cb8u;
@@ -120,10 +113,6 @@ class HalfKAv2_hm {
static IndexType make_index(Color perspective, Square s, Piece pc, Square ksq);
// Get a list of indices for active features
static void append_active_indices(Color perspective, const Position& pos, IndexList& active);
// Get a list of indices for recently changed features
static void append_changed_indices(
Color perspective, Square ksq, const DiffType& diff, IndexList& removed, IndexList& added);
src/nnue/nnue_accumulator.cpp
+2 -2
View File
@@ -358,13 +358,13 @@ void update_accumulator_incremental(Color perspective,
if constexpr (Forward)
{
ThreatFeatureSet::append_changed_indices(perspective, ksq, dirtyThreats, thrRemoved,
thrAdded, nullptr, false, pfBase, pfStride);
thrAdded, pfBase, pfStride);
PSQFeatureSet::append_changed_indices(perspective, ksq, dirtyPiece, psqRemoved, psqAdded);
}
else
{
ThreatFeatureSet::append_changed_indices(perspective, ksq, dirtyThreats, thrAdded,
thrRemoved, nullptr, false, pfBase, pfStride);
thrRemoved, pfBase, pfStride);
PSQFeatureSet::append_changed_indices(perspective, ksq, dirtyPiece, psqAdded, psqRemoved);
}
src/nnue/nnue_common.h
-2
View File
@@ -67,10 +67,8 @@ constexpr u32 Version = 0x6A448AFAu;
// Constant used in evaluation value calculation
constexpr int OutputScale = 16;
constexpr int WeightScaleBits = 6;
constexpr int FtOneVal = 256;
constexpr int FtMaxVal = 255;
constexpr int HiddenOneVal = 128;
constexpr int HiddenMaxVal = 127;
// Size of cache line (in bytes)
constexpr usize CacheLineSize = 64;
src/position.cpp
+4 -8
View File
@@ -862,12 +862,10 @@ void Position::do_move(Move m,
Piece pc = piece_on(from);
Piece captured = m.type_of() == EN_PASSANT ? make_piece(them, PAWN) : piece_on(to);
dp.pc = pc;
dp.from = from;
dp.to = to;
dp.add_sq = SQ_NONE;
dts.us = us;
dts.prevKsq = square<KING>(us);
dp.pc = pc;
dp.from = from;
dp.to = to;
dp.add_sq = SQ_NONE;
assert(color_of(pc) == us);
assert(captured == NO_PIECE || color_of(captured) == (m.type_of() != CASTLING ? them : us));
@@ -1080,8 +1078,6 @@ void Position::do_move(Move m,
}
}
dts.ksq = square<KING>(us);
assert(pos_is_ok());
assert(dp.pc != NO_PIECE);
src/types.h
-2
View File
@@ -339,8 +339,6 @@ using DirtyThreatList = ValueList<DirtyThreat, 96>;
struct DirtyThreats {
DirtyThreatList list;
Color us;
Square prevKsq, ksq;
};
#define ENABLE_INCR_OPERATORS_ON(T) \