Was a long standing hidden bug from Glaurung times,
triggered only now that we enable IID at non PV nodes.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
// Go with internal iterative deepening if we don't have a TT move
if (UseIIDAtNonPVNodes && ttMove == MOVE_NONE && depth >= 8*OnePly &&
- evaluate(pos, ei, threadID) >= beta - IIDMargin)
+ !isCheck && evaluate(pos, ei, threadID) >= beta - IIDMargin)
{
search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID);
ttMove = ss[ply].pv[ply];