Remove useless condition

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 5cdc01698f2425462fdb7ff8929fb29d55c7dcbd..ef83f4598da967c20b49d304df451d92db02c583 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -52,9 +52,6 @@ using namespace Search;
 
 namespace {
 
-  // Set to true to force running with one thread. Used for debugging
-  const bool FakeSplit = false;
-
   // Different node types, used as template parameter
   enum NodeType { Root, PV, NonPV };
 
@@ -398,7 +395,7 @@ namespace {
         if (Limits.use_time_management() && !Signals.stop && !Signals.stopOnPonderhit)
         {
             // Take some extra time if the best move has changed
-            if (depth > 4 && depth < 50 &&  MultiPV == 1)
+            if (depth > 4 && MultiPV == 1)
                 TimeMgr.pv_instability(BestMoveChanges);
 
             // Stop the search if only one legal move is available or all
@@ -566,7 +563,6 @@ namespace {
         &&  depth < 4 * ONE_PLY
         &&  eval + razor_margin(depth) <= alpha
         &&  ttMove == MOVE_NONE
-        &&  abs(beta) < VALUE_MATE_IN_MAX_PLY
         && !pos.pawn_on_7th(pos.side_to_move()))
     {
         if (   depth <= ONE_PLY
@@ -594,7 +590,6 @@ namespace {
         && !ss->skipNullMove
         &&  depth >= 2 * ONE_PLY
         &&  eval >= beta
-        &&  abs(beta) < VALUE_MATE_IN_MAX_PLY
         &&  pos.non_pawn_material(pos.side_to_move()))
     {
         ss->currentMove = MOVE_NULL;
@@ -604,7 +599,8 @@ namespace {
         // Null move dynamic reduction based on depth and value
         Depth R =  3 * ONE_PLY
                  + depth / 4
-                 + int(eval - beta) / PawnValueMg * ONE_PLY;
+                 + (abs(beta) < VALUE_KNOWN_WIN ? int(eval - beta) / PawnValueMg * ONE_PLY
+                                                : DEPTH_ZERO);
 
         pos.do_null_move(st);
         (ss+1)->skipNullMove = true;
@@ -619,7 +615,7 @@ namespace {
             if (nullValue >= VALUE_MATE_IN_MAX_PLY)
                 nullValue = beta;
 
-            if (depth < 12 * ONE_PLY)
+            if (depth < 12 * ONE_PLY && abs(beta) < VALUE_KNOWN_WIN)
                 return nullValue;
 
             // Do verification search at high depths
@@ -699,7 +695,10 @@ moves_loop: // When in check and at SpNode search starts from here
     singularExtensionNode =   !RootNode
                            && !SpNode
                            &&  depth >= 8 * ONE_PLY
+                           &&  abs(beta) < VALUE_KNOWN_WIN
                            &&  ttMove != MOVE_NONE
+                       /*  &&  ttValue != VALUE_NONE Already implicit in the next condition */
+                           &&  abs(ttValue) < VALUE_KNOWN_WIN
                            && !excludedMove // Recursive singular search is not allowed
                            && (tte->bound() & BOUND_LOWER)
                            &&  tte->depth() >= depth - 3 * ONE_PLY;
@@ -764,11 +763,8 @@ moves_loop: // When in check and at SpNode search starts from here
       if (    singularExtensionNode
           &&  move == ttMove
           && !ext
-          &&  pos.legal(move, ci.pinned)
-          &&  abs(ttValue) < VALUE_KNOWN_WIN)
+          &&  pos.legal(move, ci.pinned))
       {
-          assert(ttValue != VALUE_NONE);
-
           Value rBeta = ttValue - int(depth);
           ss->excludedMove = move;
           ss->skipNullMove = true;
@@ -988,8 +984,8 @@ moves_loop: // When in check and at SpNode search starts from here
       {
           assert(bestValue > -VALUE_INFINITE && bestValue < beta);
 
-          thisThread->split<FakeSplit>(pos, ss, alpha, beta, &bestValue, &bestMove,
-                                       depth, moveCount, &mp, NT, cutNode);
+          thisThread->split(pos, ss, alpha, beta, &bestValue, &bestMove,
+                            depth, moveCount, &mp, NT, cutNode);
 
           if (Signals.stop || thisThread->cutoff_occurred())
               return VALUE_ZERO;