From: Marco Costalba Date: Thu, 1 Nov 2012 13:49:54 +0000 (+0100) Subject: Pass InCheck as template parameter of qsearch() X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=c039103b3177c481947053240b322fb8289240d8 Pass InCheck as template parameter of qsearch() Instead of use a variable so to resolve many conditions already at compile time. In quiesce is also where we have most of the InCheck nodes and is one of the most performance critical code paths. Speed up of 1.5% with Clang and 1% with gcc Suggested by Hongzhi Cheng. No functional change. --- diff --git a/src/search.cpp b/src/search.cpp index ed8aa777..76cc8e8d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -96,7 +96,7 @@ namespace { template Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); - template + template Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); void id_loop(Position& pos); @@ -626,7 +626,7 @@ namespace { && !pos.pawn_on_7th(pos.side_to_move())) { Value rbeta = beta - razor_margin(depth); - Value v = qsearch(pos, ss, rbeta-1, rbeta, DEPTH_ZERO); + Value v = qsearch(pos, ss, rbeta-1, rbeta, DEPTH_ZERO); if (v < rbeta) // Logically we should return (v + razor_margin(depth)), but // surprisingly this did slightly weaker in tests. @@ -665,7 +665,7 @@ namespace { pos.do_null_move(st); (ss+1)->skipNullMove = true; - nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) + nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) : - search(pos, ss+1, -beta, -alpha, depth-R); (ss+1)->skipNullMove = false; pos.do_null_move(st); @@ -935,7 +935,9 @@ split_point_start: // At split points actual search starts from here if (doFullDepthSearch) { alpha = SpNode ? sp->alpha : alpha; - value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) + value = newDepth < ONE_PLY ? + givesCheck ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) + : -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) : - search(pos, ss+1, -(alpha+1), -alpha, newDepth); } @@ -943,9 +945,10 @@ split_point_start: // At split points actual search starts from here // high, in the latter case search only if value < beta, otherwise let the // parent node to fail low with value <= alpha and to try another move. if (PvNode && (pvMove || (value > alpha && (RootNode || value < beta)))) - value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) + value = newDepth < ONE_PLY ? + givesCheck ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) + : -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) : - search(pos, ss+1, -beta, -alpha, newDepth); - // Step 17. Undo move pos.undo_move(move); @@ -1086,12 +1089,13 @@ split_point_start: // At split points actual search starts from here // search function when the remaining depth is zero (or, to be more precise, // less than ONE_PLY). - template + template Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { const bool PvNode = (NT == PV); assert(NT == PV || NT == NonPV); + assert(InCheck == pos.in_check()); assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE); assert(PvNode || (alpha == beta - 1)); assert(depth <= DEPTH_ZERO); @@ -1101,10 +1105,9 @@ split_point_start: // At split points actual search starts from here Key posKey; Move ttMove, move, bestMove; Value bestValue, value, ttValue, futilityValue, futilityBase; - bool inCheck, givesCheck, enoughMaterial, evasionPrunable; + bool givesCheck, enoughMaterial, evasionPrunable; Depth ttDepth; - inCheck = pos.in_check(); ss->currentMove = bestMove = MOVE_NONE; ss->ply = (ss-1)->ply + 1; @@ -1122,7 +1125,7 @@ split_point_start: // At split points actual search starts from here // Decide whether or not to include checks, this fixes also the type of // TT entry depth that we are going to use. Note that in qsearch we use // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS. - ttDepth = inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS + ttDepth = InCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS; if ( tte && tte->depth() >= ttDepth @@ -1136,7 +1139,7 @@ split_point_start: // At split points actual search starts from here } // Evaluate the position statically - if (inCheck) + if (InCheck) { ss->staticEval = ss->evalMargin = VALUE_NONE; bestValue = futilityBase = -VALUE_INFINITE; @@ -1190,7 +1193,7 @@ split_point_start: // At split points actual search starts from here // Futility pruning if ( !PvNode - && !inCheck + && !InCheck && !givesCheck && move != ttMove && enoughMaterial @@ -1218,14 +1221,14 @@ split_point_start: // At split points actual search starts from here // Detect non-capture evasions that are candidate to be pruned evasionPrunable = !PvNode - && inCheck + && InCheck && bestValue > VALUE_MATED_IN_MAX_PLY && !pos.is_capture(move) && !pos.can_castle(pos.side_to_move()); // Don't search moves with negative SEE values if ( !PvNode - && (!inCheck || evasionPrunable) + && (!InCheck || evasionPrunable) && move != ttMove && type_of(move) != PROMOTION && pos.see_sign(move) < 0) @@ -1233,7 +1236,7 @@ split_point_start: // At split points actual search starts from here // Don't search useless checks if ( !PvNode - && !inCheck + && !InCheck && givesCheck && move != ttMove && !pos.is_capture_or_promotion(move) @@ -1249,7 +1252,8 @@ split_point_start: // At split points actual search starts from here // Make and search the move pos.do_move(move, st, ci, givesCheck); - value = -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY); + value = givesCheck ? -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY) + : -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY); pos.undo_move(move); assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); @@ -1279,7 +1283,7 @@ split_point_start: // At split points actual search starts from here // All legal moves have been searched. A special case: If we're in check // and no legal moves were found, it is checkmate. - if (inCheck && bestValue == -VALUE_INFINITE) + if (InCheck && bestValue == -VALUE_INFINITE) return mated_in(ss->ply); // Plies to mate from the root TT.store(posKey, value_to_tt(bestValue, ss->ply),