Greatly speedup has_mate_threat()

[stockfish] / src / movegen.cpp

diff --git a/src/movegen.cpp b/src/movegen.cpp
index d2b55bd28053f262c2513bdfd17c19a0b307041d..b3a25806aaa5593ae064ca5d816735e4806dc628 100644 (file)
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -73,9 +73,8 @@ namespace {
         return Us == WHITE ? p << 9 : p >> 7;
     else if (Direction == DELTA_NW)
         return Us == WHITE ? p << 7 : p >> 9;
-
-    assert(false);
-    return p;
+    else
+        return p;
   }
 
   // Template generate_piece_checks() with specializations
@@ -177,10 +176,10 @@ int generate_noncaptures(const Position& pos, MoveStack* mlist) {
 }
 
 
-/// generate_checks() generates all pseudo-legal non-capturing, non-promoting
-/// checks. It returns the number of generated moves.
+/// generate_non_capture_checks() generates all pseudo-legal non-capturing,
+/// non-promoting checks. It returns the number of generated moves.
 
-int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
+int generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
 
   assert(pos.is_ok());
   assert(!pos.is_check());
@@ -821,6 +820,11 @@ namespace {
     while (b)
     {
         Square from = pop_1st_bit(&b);
+        if (   (Piece == QUEEN  && !(QueenPseudoAttacks[from]  & checkSqs))
+            || (Piece == ROOK   && !(RookPseudoAttacks[from]   & checkSqs))
+            || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
+            continue;
+
         Bitboard bb = pos.piece_attacks<Piece>(from) & checkSqs;
         SERIALIZE_MOVES(bb);
     }