From 0e82bf6495ddefa1bfee158d242a2d58432cee5d Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Sat, 19 Mar 2016 22:22:40 +0100
Subject: [PATCH] Prevent infinite loops on repetitions.

---
 src/main.cpp | 3 +++
 1 file changed, 3 insertions(+)

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);
-- 
2.39.2