Fix Potential in TB cutoffs for NMP.

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 9b686a529744e0be04ba65f7d06821b85d01052f..740ad71efee01461cc40b5992c757f2caa4db81e 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -801,10 +801,9 @@ namespace {
         if (nullValue >= beta)
         {
             // Do not return unproven mate or TB scores
-            if (nullValue >= VALUE_TB_WIN_IN_MAX_PLY)
-                nullValue = beta;
+            nullValue = std::min(nullValue, VALUE_TB_WIN_IN_MAX_PLY-1);
 
-            if (thisThread->nmpMinPly || (abs(beta) < VALUE_KNOWN_WIN && depth < 14))
+            if (thisThread->nmpMinPly || depth < 14)
                 return nullValue;
 
             assert(!thisThread->nmpMinPly); // Recursive verification is not allowed