Revert "Don't prune discovered checks"

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 35a396814d676f4878738150ddd129d20e551bb1..3ffd8ae4c780262937f98e7f83227017b7d29c08 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -483,8 +483,7 @@ namespace {
     Depth ext, newDepth;
     Value bestValue, value, ttValue;
     Value eval, nullValue, futilityValue;
-    CheckType givesCheck;
-    bool inCheck, pvMove, singularExtensionNode;
+    bool inCheck, givesCheck, pvMove, singularExtensionNode;
     bool captureOrPromotion, dangerous, doFullDepthSearch;
     int moveCount, playedMoveCount;
 
@@ -816,7 +815,7 @@ split_point_start: // At split points actual search starts from here
       if (PvNode && dangerous)
           ext = ONE_PLY;
 
-      else if (givesCheck && (givesCheck == DISCO_CHECK || pos.see_sign(move) >= 0))
+      else if (givesCheck && pos.see_sign(move) >= 0)
           ext = ONE_PLY / 2;
 
       // Singular extension search. If all moves but one fail low on a search of
@@ -883,7 +882,6 @@ split_point_start: // At split points actual search starts from here
 
           // Prune moves with negative SEE at low depths
           if (   predictedDepth < 2 * ONE_PLY
-              && givesCheck != DISCO_CHECK
               && pos.see_sign(move) < 0)
           {
               if (SpNode)
@@ -1104,8 +1102,7 @@ split_point_start: // At split points actual search starts from here
     Key posKey;
     Move ttMove, move, bestMove;
     Value bestValue, value, ttValue, futilityValue, futilityBase;
-    CheckType givesCheck;
-    bool enoughMaterial, evasionPrunable, fromNull;
+    bool givesCheck, enoughMaterial, evasionPrunable, fromNull;
     Depth ttDepth;
 
     ss->currentMove = bestMove = MOVE_NONE;
@@ -1237,7 +1234,6 @@ split_point_start: // At split points actual search starts from here
       if (   !PvNode
           && (!InCheck || evasionPrunable)
           &&  move != ttMove
-          &&  givesCheck != DISCO_CHECK
           &&  type_of(move) != PROMOTION
           &&  pos.see_sign(move) < 0)
           continue;