From: H.G.Muller <hgm@hgm-xboard.(none)>
Date: Tue, 7 Feb 2017 19:28:38 +0000 (+0100)
Subject: Prevent check evasions can become killers
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=df099d8cf121ff48f705a3137257490f3e75174f;p=crazywa.git

Prevent check evasions can become killers

Check evasions are tactical replies specific to the preceding moves
(as checks cannot be pre-existing), and are thus not suitable for trying
in sibbling nodes that do not check. It is even unlikely they would carry
over to other checks.
---

diff --git a/dropper.c b/dropper.c
index 155be56..49379dc 100644
--- a/dropper.c
+++ b/dropper.c
@@ -1325,7 +1325,7 @@ printf("%d:%d:%d %2d. %08x %c%d%c%d %6d %6d %6d\n",ply,depth,iterDepth,curMove,m
 		    if(score > INF-100 && curMove >= m.nonCapts)
 			mateKillers[(ff->wholeMove & 0xFFFF) + (stm - WHITE << 11)] = moveStack[curMove] & 0xFFFF | f.xking << 16 | board[f.toSqr] << 24; // store mate killers
 		    if(score >= beta) { // beta cutoff
-			if(curMove >= m.nonCapts && moveStack[curMove] != killers[ply][1])
+			if(f.checker == CK_NONE && curMove >= m.nonCapts && moveStack[curMove] != killers[ply][1])
 			    killers[ply][0] = killers[ply][1], killers[ply][1] = moveStack[curMove];
 			resultDepth = f.depth;
 			goto cutoff; // done with this node