Fix sometimes incorrect key for prefetches

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index 0686d245bc77fe956f3a8e15a7f86360e610c38d..ae1da017770cd34ea79eabfc961a27359eb0ad61 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -1013,9 +1013,9 @@ void Position::do_null_move(StateInfo& newSt) {
   }
 
   st->key ^= Zobrist::side;
+  ++st->rule50;
   prefetch(TT.first_entry(key()));
 
-  ++st->rule50;
   st->pliesFromNull = 0;
 
   sideToMove = ~sideToMove;