From: Marco Costalba <mcostalba@gmail.com>
Date: Tue, 14 Sep 2010 08:39:12 +0000 (+0200)
Subject: Do not update killers in qsearch
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=c1558dde12620fdf1995c08d3a09cb4c18b4539a

Do not update killers in qsearch

It seems totally unuseful because killers are not
used to order the moves in qsearch. Although there
is some functionality change, probably just a small
side effect.

After 5656 games on rc
Mod vs Orig: 1007 - 980 - 3669  ELO +1 (+- 3.7)

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---

diff --git a/src/search.cpp b/src/search.cpp
index e1245085..df4c8540 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1544,11 +1544,6 @@ namespace {
     ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
     TT.store(pos.get_key(), value_to_tt(bestValue, ply), vt, d, ss->bestMove, ss->eval, evalMargin);
 
-    // Update killers only for checking moves that fails high
-    if (    bestValue >= beta
-        && !pos.move_is_capture_or_promotion(ss->bestMove))
-        update_killers(ss->bestMove, ss);
-
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
 
     return bestValue;