Simplify move generation (1/2)

BM123499 · snicolet · commit 4b509559fbab · 2021-03-16T22:32:53.000+01:00
STC: LLR: 2.95 (-2.94,2.94) {-1.25,0.25} Total: 29792 W: 2611 L: 2545 D: 24636 Ptnml(0-2): 94, 1982, 10659, 2086, 75 https://tests.stockfishchess.org/tests/view/604fe5b62433018de7a38ba8 LTC: LLR: 2.92 (-2.94,2.94) {-0.75,0.25} Total: 22040 W: 826 L: 777 D: 20437 Ptnml(0-2): 8, 646, 9664, 693, 9 https://tests.stockfishchess.org/tests/view/604fec892433018de7a38bac Closes #3399 No functional change
diff --git a/src/movegen.cpp b/src/movegen.cpp
@@ -182,17 +182,12 @@ namespace {
 
     Bitboard bb = piecesToMove & pos.pieces(Pt);
 
-    if (!bb)
-        return moveList;
-
-    [[maybe_unused]] const Bitboard checkSquares = pos.check_squares(Pt);
-
     while (bb) {
         Square from = pop_lsb(&bb);
 
         Bitboard b = attacks_bb<Pt>(from, pos.pieces()) & target;
         if constexpr (Checks)
-            b &= checkSquares;
+            b &= pos.check_squares(Pt);
 
         while (b)
             *moveList++ = make_move(from, pop_lsb(&b));
