// smooth experience in analysis mode. We don't probe at Root nodes otherwise
// we should also update RootMoveList to avoid bogus output.
if ( !RootNode
- && tte && tte->depth() >= depth
+ && tte
+ && tte->depth() >= depth
+ && ttValue != VALUE_NONE // Only in case of TT access race
&& ( PvNode ? tte->type() == BOUND_EXACT
: ttValue >= beta ? (tte->type() & BOUND_LOWER)
: (tte->type() & BOUND_UPPER)))
{
- assert(ttValue != VALUE_NONE); // Due to depth > DEPTH_NONE
-
TT.refresh(tte);
ss->currentMove = ttMove; // Can be MOVE_NONE
else if (tte)
{
- assert(tte->static_value() != VALUE_NONE);
- assert(ttValue != VALUE_NONE || tte->type() == BOUND_NONE);
+ // Following asserts are valid only in single thread condition because
+ // TT access is always racy and its contents cannot be trusted.
+ assert(tte->static_value() != VALUE_NONE || Threads.size() > 1);
+ assert(ttValue != VALUE_NONE || tte->type() == BOUND_NONE || Threads.size() > 1);
ss->staticEval = eval = tte->static_value();
ss->evalMargin = tte->static_value_margin();
+ if (eval == VALUE_NONE || ss->evalMargin == VALUE_NONE) // Due to a race
+ eval = ss->staticEval = evaluate(pos, ss->evalMargin);
+
// Can ttValue be used as a better position evaluation?
- if ( ((tte->type() & BOUND_LOWER) && ttValue > eval)
- || ((tte->type() & BOUND_UPPER) && ttValue < eval))
- eval = ttValue;
+ if (ttValue != VALUE_NONE)
+ if ( ((tte->type() & BOUND_LOWER) && ttValue > eval)
+ || ((tte->type() & BOUND_UPPER) && ttValue < eval))
+ eval = ttValue;
}
else
{
// only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
ttDepth = inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
: DEPTH_QS_NO_CHECKS;
- if ( tte && tte->depth() >= ttDepth
+ if ( tte
+ && tte->depth() >= ttDepth
+ && ttValue != VALUE_NONE // Only in case of TT access race
&& ( PvNode ? tte->type() == BOUND_EXACT
: ttValue >= beta ? (tte->type() & BOUND_LOWER)
: (tte->type() & BOUND_UPPER)))
{
- assert(ttValue != VALUE_NONE); // Due to ttDepth > DEPTH_NONE
-
ss->currentMove = ttMove; // Can be MOVE_NONE
return ttValue;
}
{
if (tte)
{
- assert(tte->static_value() != VALUE_NONE);
+ assert(tte->static_value() != VALUE_NONE || Threads.size() > 1);
ss->staticEval = bestValue = tte->static_value();
ss->evalMargin = tte->static_value_margin();
+
+ if (ss->staticEval == VALUE_NONE || ss->evalMargin == VALUE_NONE) // Due to a race
+ ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);
}
else
ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);