idk

bench 1743758

src/search.cpp

@@ -848,7 +848,7 @@ Value Search::Worker::search(
     // If we have a good enough capture (or queen promotion) and a reduced search
     // returns a value much above beta, we can (almost) safely prune the previous move.
     probCutBeta = beta + 174 - 56 * improving;
-    if (depth > 3
+    if (depth >= 3
         && !is_decisive(beta)
         // If value from transposition table is lower than probCutBeta, don't attempt
         // probCut there and in further interactions with transposition table cutoff
@@ -859,6 +859,7 @@ Value Search::Worker::search(
         assert(probCutBeta < VALUE_INFINITE && probCutBeta > beta);
 
         MovePicker mp(pos, ttData.move, probCutBeta - ss->staticEval, &thisThread->captureHistory);
+        Depth      probCutDepth = std::max(depth - 4, 0);
 
         while ((move = mp.next_move()) != Move::none())
         {
@@ -888,17 +889,17 @@ Value Search::Worker::search(
             value = -qsearch<NonPV>(pos, ss + 1, -probCutBeta, -probCutBeta + 1);
 
             // If the qsearch held, perform the regular search
-            if (value >= probCutBeta)
+            if (value >= probCutBeta && probCutDepth > 0)
                 value =
-                  -search<NonPV>(pos, ss + 1, -probCutBeta, -probCutBeta + 1, depth - 4, !cutNode);
+                  -search<NonPV>(pos, ss + 1, -probCutBeta, -probCutBeta + 1, probCutDepth, !cutNode);
 
             pos.undo_move(move);
 
             if (value >= probCutBeta)
             {
                 // Save ProbCut data into transposition table
                 ttWriter.write(posKey, value_to_tt(value, ss->ply), ss->ttPv, BOUND_LOWER,
-                               depth - 3, move, unadjustedStaticEval, tt.generation());
+                               probCutDepth + 1, move, unadjustedStaticEval, tt.generation());
 
                 if (!is_decisive(value))
                     return value - (probCutBeta - beta);