From: Marco Costalba <mcostalba@gmail.com>
Date: Tue, 15 Dec 2009 11:07:23 +0000 (+0100)
Subject: In non-PV IID don't call evaluate when in check
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=0d88b832e38430e0add9c8298458569b23e102a7;ds=sidebyside

In non-PV IID don't call evaluate when in check

Was a long standing hidden bug from Glaurung times,
triggered only now that we enable IID at non PV nodes.

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

diff --git a/src/search.cpp b/src/search.cpp
index f7a39943..4481cfc7 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1435,7 +1435,7 @@ namespace {
 
     // Go with internal iterative deepening if we don't have a TT move
     if (UseIIDAtNonPVNodes && ttMove == MOVE_NONE && depth >= 8*OnePly &&
-        evaluate(pos, ei, threadID) >= beta - IIDMargin)
+        !isCheck && evaluate(pos, ei, threadID) >= beta - IIDMargin)
     {
         search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID);
         ttMove = ss[ply].pv[ply];