From: VoyagerOne <excelgeek@gmail.com>
Date: Fri, 18 Oct 2019 13:23:00 +0000 (-0400)
Subject: Current capture for Counter-Move history
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=472de897cb7efb66cb3518f3f4924716bd8abaee

Current capture for Counter-Move history

Use current capture to index the CMH table instead of prior capture.

STC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 61908 W: 13626 L: 13220 D: 35062
http://tests.stockfishchess.org/tests/view/5da8aa670ebc597ba8eda558

LTC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 49057 W: 8071 L: 7765 D: 33221
http://tests.stockfishchess.org/tests/view/5da8e99d0ebc597ba8eda9ca

Closes https://github.com/official-stockfish/Stockfish/pull/2362

Bench: 4423737
---

diff --git a/src/search.cpp b/src/search.cpp
index 7e2df215..6e59bb54 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -864,12 +864,17 @@ namespace {
                && probCutCount < 2 + 2 * cutNode)
             if (move != excludedMove && pos.legal(move))
             {
+                assert(pos.capture_or_promotion(move));
+                assert(depth >= 5);
+
+                captureOrPromotion = true;
                 probCutCount++;
 
                 ss->currentMove = move;
-                ss->continuationHistory = &thisThread->continuationHistory[inCheck][priorCapture][pos.moved_piece(move)][to_sq(move)];
-
-                assert(depth >= 5);
+                ss->continuationHistory = &thisThread->continuationHistory[inCheck]
+                                                                          [captureOrPromotion]
+                                                                          [pos.moved_piece(move)]
+                                                                          [to_sq(move)];
 
                 pos.do_move(move, st);
 
@@ -900,8 +905,8 @@ namespace {
 moves_loop: // When in check, search starts from here
 
     const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory,
-                                          nullptr, (ss-4)->continuationHistory,
-                                          nullptr, (ss-6)->continuationHistory };
+                                          nullptr                   , (ss-4)->continuationHistory,
+                                          nullptr                   , (ss-6)->continuationHistory };
 
     Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq];
 
@@ -911,7 +916,7 @@ moves_loop: // When in check, search starts from here
                                       countermove,
                                       ss->killers);
 
-    value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
+    value = bestValue;
     moveCountPruning = false;
     ttCapture = ttMove && pos.capture_or_promotion(ttMove);
 
@@ -1068,7 +1073,10 @@ moves_loop: // When in check, search starts from here
 
       // Update the current move (this must be done after singular extension search)
       ss->currentMove = move;
-      ss->continuationHistory = &thisThread->continuationHistory[inCheck][priorCapture][movedPiece][to_sq(move)];
+      ss->continuationHistory = &thisThread->continuationHistory[inCheck]
+                                                                [captureOrPromotion]
+                                                                [movedPiece]
+                                                                [to_sq(move)];
 
       // Step 15. Make the move
       pos.do_move(move, st, givesCheck);
@@ -1323,7 +1331,7 @@ moves_loop: // When in check, search starts from here
     Move ttMove, move, bestMove;
     Depth ttDepth;
     Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
-    bool ttHit, pvHit, inCheck, givesCheck, evasionPrunable, priorCapture;
+    bool ttHit, pvHit, inCheck, givesCheck, captureOrPromotion, evasionPrunable;
     int moveCount;
 
     if (PvNode)
@@ -1337,7 +1345,6 @@ moves_loop: // When in check, search starts from here
     (ss+1)->ply = ss->ply + 1;
     bestMove = MOVE_NONE;
     inCheck = pos.checkers();
-    priorCapture = pos.captured_piece();
     moveCount = 0;
 
     // Check for an immediate draw or maximum ply reached
@@ -1408,8 +1415,8 @@ moves_loop: // When in check, search starts from here
     }
 
     const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory,
-                                          nullptr, (ss-4)->continuationHistory,
-                                          nullptr, (ss-6)->continuationHistory };
+                                          nullptr                   , (ss-4)->continuationHistory,
+                                          nullptr                   , (ss-6)->continuationHistory };
 
     // Initialize a MovePicker object for the current position, and prepare
     // to search the moves. Because the depth is <= 0 here, only captures,
@@ -1426,6 +1433,7 @@ moves_loop: // When in check, search starts from here
       assert(is_ok(move));
 
       givesCheck = pos.gives_check(move);
+      captureOrPromotion = pos.capture_or_promotion(move);
 
       moveCount++;
 
@@ -1475,7 +1483,10 @@ moves_loop: // When in check, search starts from here
       }
 
       ss->currentMove = move;
-      ss->continuationHistory = &thisThread->continuationHistory[inCheck][priorCapture][pos.moved_piece(move)][to_sq(move)];
+      ss->continuationHistory = &thisThread->continuationHistory[inCheck]
+                                                                [captureOrPromotion]
+                                                                [pos.moved_piece(move)]
+                                                                [to_sq(move)];
 
       // Make and search the move
       pos.do_move(move, st, givesCheck);