Simplification in LMR

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index fef1b518160abf00e7e6e4ac14a7e656d2ed4046..f412d9d6f1a1573fefbadeccdbed2d7513115ca9 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1159,22 +1159,18 @@ moves_loop: // When in check, search starts from here
           if (cutNode && move != ss->killers[0])
               r += 2;
 
-          if (!captureOrPromotion)
-          {
-              // Increase reduction if ttMove is a capture (~3 Elo)
-              if (ttCapture)
-                  r++;
-
-              ss->statScore =  thisThread->mainHistory[us][from_to(move)]
-                             + (*contHist[0])[movedPiece][to_sq(move)]
-                             + (*contHist[1])[movedPiece][to_sq(move)]
-                             + (*contHist[3])[movedPiece][to_sq(move)]
-                             - 4923;
-
-              // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
-              if (!ss->inCheck)
-                  r -= ss->statScore / 14721;
-          }
+          // Increase reduction if ttMove is a capture (~3 Elo)
+          if (ttCapture)
+              r++;
+
+          ss->statScore =  thisThread->mainHistory[us][from_to(move)]
+                         + (*contHist[0])[movedPiece][to_sq(move)]
+                         + (*contHist[1])[movedPiece][to_sq(move)]
+                         + (*contHist[3])[movedPiece][to_sq(move)]
+                         - 4923;
+
+          // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
+          r -= ss->statScore / 14721;
 
           // In general we want to cap the LMR depth search at newDepth. But if
           // reductions are really negative and movecount is low, we allow this move
@@ -1472,6 +1468,10 @@ moves_loop: // When in check, search starts from here
     {
       assert(is_ok(move));
 
+      // Check for legality
+      if (!pos.legal(move))
+          continue;
+
       givesCheck = pos.gives_check(move);
       captureOrPromotion = pos.capture_or_promotion(move);
 
@@ -1510,13 +1510,6 @@ moves_loop: // When in check, search starts from here
       // Speculative prefetch as early as possible
       prefetch(TT.first_entry(pos.key_after(move)));
 
-      // Check for legality just before making the move
-      if (!pos.legal(move))
-      {
-          moveCount--;
-          continue;
-      }
-
       ss->currentMove = move;
       ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
                                                                 [captureOrPromotion]