Assorted trivial cleanups

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 6e59bb541780b37913aadc84b864b69588dd56b0..e0dcc4d1346a71c1766427f4d9d482db8f7cc9f5 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -75,7 +75,7 @@ namespace {
     return (r + 520) / 1024 + (!i && r > 999);
   }
 
-  constexpr int futility_move_count(bool improving, int depth) {
+  constexpr int futility_move_count(bool improving, Depth depth) {
     return (5 + depth * depth) * (1 + improving) / 2;
   }
 
@@ -594,17 +594,17 @@ namespace {
     Move ttMove, move, excludedMove, bestMove;
     Depth extension, newDepth;
     Value bestValue, value, ttValue, eval, maxValue;
-    bool ttHit, ttPv, inCheck, givesCheck, improving, doLMR, priorCapture;
-    bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture;
+    bool ttHit, ttPv, inCheck, givesCheck, improving, didLMR, priorCapture;
+    bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture, singularLMR;
     Piece movedPiece;
-    int moveCount, captureCount, quietCount, singularLMR;
+    int moveCount, captureCount, quietCount;
 
     // Step 1. Initialize node
     Thread* thisThread = pos.this_thread();
     inCheck = pos.checkers();
     priorCapture = pos.captured_piece();
     Color us = pos.side_to_move();
-    moveCount = captureCount = quietCount = singularLMR = ss->moveCount = 0;
+    moveCount = captureCount = quietCount = ss->moveCount = 0;
     bestValue = -VALUE_INFINITE;
     maxValue = VALUE_INFINITE;
 
@@ -917,7 +917,7 @@ moves_loop: // When in check, search starts from here
                                       ss->killers);
 
     value = bestValue;
-    moveCountPruning = false;
+    singularLMR = moveCountPruning = false;
     ttCapture = ttMove && pos.capture_or_promotion(ttMove);
 
     // Mark this node as being searched
@@ -980,10 +980,7 @@ moves_loop: // When in check, search starts from here
           if (value < singularBeta)
           {
               extension = 1;
-              singularLMR++;
-
-              if (value < singularBeta - std::min(4 * depth, 36))
-                  singularLMR++;
+              singularLMR = true;
           }
 
           // Multi-cut pruning
@@ -1106,7 +1103,8 @@ moves_loop: // When in check, search starts from here
               r--;
 
           // Decrease reduction if ttMove has been singularly extended
-          r -= singularLMR;
+          if (singularLMR)
+              r -= 2;
 
           if (!captureOrPromotion)
           {
@@ -1153,17 +1151,17 @@ moves_loop: // When in check, search starts from here
 
           value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
 
-          doFullDepthSearch = (value > alpha && d != newDepth), doLMR = true;
+          doFullDepthSearch = (value > alpha && d != newDepth), didLMR = true;
       }
       else
-          doFullDepthSearch = !PvNode || moveCount > 1, doLMR = false;
+          doFullDepthSearch = !PvNode || moveCount > 1, didLMR = false;
 
       // Step 17. Full depth search when LMR is skipped or fails high
       if (doFullDepthSearch)
       {
           value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);
 
-          if (doLMR && !captureOrPromotion)
+          if (didLMR && !captureOrPromotion)
           {
               int bonus = value > alpha ?  stat_bonus(newDepth)
                                         : -stat_bonus(newDepth);
@@ -1468,7 +1466,7 @@ moves_loop: // When in check, search starts from here
 
       // Don't search moves with negative SEE values
       if (  (!inCheck || evasionPrunable)
-          && (!givesCheck || !(pos.blockers_for_king(~pos.side_to_move()) & from_sq(move)))
+          && !(givesCheck && pos.is_discovery_check_on_king(~pos.side_to_move(), move))
           && !pos.see_ge(move))
           continue;