From 9fd5b44d60c53357bb76d4c51f20d3d5aa31ebe3 Mon Sep 17 00:00:00 2001 From: "J. Oster" Date: Mon, 31 May 2021 17:46:40 +0200 Subject: [PATCH] Pre-initialize ss->ply We pre-initialize ss->ply over the whole stack. There is no need to re-assign the same value(s) over and over again while searching. Probably a tiny speedup on longer searches. Tested for no regression: STC LLR: 2.93 (-2.94,2.94) <-2.50,0.50> Total: 25784 W: 2205 L: 2101 D: 21478 Ptnml(0-2): 62, 1660, 9368, 1716, 86 https://tests.stockfishchess.org/tests/view/60b516c6457376eb8bca9dfa LTC LLR: 2.94 (-2.94,2.94) <-2.50,0.50> Total: 26200 W: 944 L: 878 D: 24378 Ptnml(0-2): 12, 732, 11545, 800, 11 https://tests.stockfishchess.org/tests/view/60b53652457376eb8bca9e0e closes https://github.com/official-stockfish/Stockfish/pull/3516 No functional change. --- src/search.cpp | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 2b4e4f1e..dac326e2 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -253,7 +253,7 @@ void Thread::search() { // To allow access to (ss-7) up to (ss+2), the stack must be oversized. // The former is needed to allow update_continuation_histories(ss-1, ...), // which accesses its argument at ss-6, also near the root. - // The latter is needed for statScores and killer initialization. + // The latter is needed for statScore and killer initialization. Stack stack[MAX_PLY+10], *ss = stack+7; Move pv[MAX_PLY+1]; Value bestValue, alpha, beta, delta; @@ -268,6 +268,9 @@ void Thread::search() { for (int i = 7; i > 0; i--) (ss-i)->continuationHistory = &this->continuationHistory[0][0][NO_PIECE][0]; // Use as a sentinel + for (int i = 0; i <= MAX_PLY + 2; ++i) + (ss+i)->ply = i; + ss->pv = pv; bestValue = delta = alpha = -VALUE_INFINITE; @@ -607,7 +610,6 @@ namespace { assert(0 <= ss->ply && ss->ply < MAX_PLY); - (ss+1)->ply = ss->ply + 1; (ss+1)->ttPv = false; (ss+1)->excludedMove = bestMove = MOVE_NONE; (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; @@ -1379,7 +1381,6 @@ moves_loop: // When in check, search starts from here } Thread* thisThread = pos.this_thread(); - (ss+1)->ply = ss->ply + 1; bestMove = MOVE_NONE; ss->inCheck = pos.checkers(); moveCount = 0; -- 2.39.2