From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Sat, 19 Mar 2016 21:22:40 +0000 (+0100)
Subject: Prevent infinite loops on repetitions.
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=0e82bf6495ddefa1bfee158d242a2d58432cee5d

Prevent infinite loops on repetitions.
---

diff --git a/src/main.cpp b/src/main.cpp
index 4be9aaf3..299b4135 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -114,9 +114,12 @@ public:
 
 			// Follow the PV until we hit an illegal move.
 			std::stack<Move> pv;
+			std::set<Key> seen;
 			while (found && is_ok(entry->move())) {
 				FillMove(entry->move(), response->add_pv());
+				if (seen.count(pos->key())) break;
 				pv.push(entry->move());
+				seen.insert(pos->key());
 				setup_states->push(StateInfo());
 				pos->do_move(entry->move(), setup_states->top(), pos->gives_check(entry->move(), CheckInfo(*pos)));
 				entry = TT.probe(pos->key(), found);