From 9a3fc4d3fb81e5f517ecde5dad8aabf55fb2bd22 Mon Sep 17 00:00:00 2001
From: Joona Kiiski <joona.kiiski@gmail.com>
Date: Tue, 13 Apr 2010 18:25:50 +0300
Subject: [PATCH] Fix evasion pruning condition

Avoid incorrect mate scores in positions like

BK5/1R4b1/2k1Np2/3p3b/2p3pq/p1rB4/n2n1p2/8 w - -

Thanks for Jouni Uski for reporting the problem

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---
 src/search.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/search.cpp b/src/search.cpp
index efdb287f..fff523c3 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1713,7 +1713,7 @@ namespace {
 
       // Detect blocking evasions that are candidate to be pruned
       evasionPrunable =   isCheck
-                       && bestValue != -VALUE_INFINITE
+                       && bestValue > value_mated_in(PLY_MAX)
                        && !pos.move_is_capture(move)
                        && pos.type_of_piece_on(move_from(move)) != KING
                        && !pos.can_castle(pos.side_to_move());
-- 
2.39.2