MovePicker: fix a nasty bug in EvalInfo optimization

EvalInfo has missing attack info when a specialized
endgame function is used.

We missed this case and were using an empty attack bitboard
instead so that no captures were generated for endgames.

After testing the EvalInfo optimization gave worst results,
so after a (long) debug session this nasty bug was found.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/movepick.cpp b/src/movepick.cpp
index b1dcea0111b8c0156883029dacc5e5be02ecaafc..43f30f7709565e22502e6e94438a0aa91ac663d1 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -78,11 +78,14 @@ MovePicker::MovePicker(const Position& p, bool pv, Move ttm,
   numOfBadCaptures = 0;
 
   // With EvalInfo we are able to know how many captures are possible before
   numOfBadCaptures = 0;
 
   // With EvalInfo we are able to know how many captures are possible before

-  // generating them. So avoid generating them in case we know are zero.
+  // generating them. So avoid generating in case we know are zero.

   Color us = pos.side_to_move();
   Color them = opposite_color(us);
   Color us = pos.side_to_move();
   Color them = opposite_color(us);

-  bool noAttacks = ei && (ei->attackedBy[us][0] & pos.pieces_of_color(them)) == 0;
-  bool noCaptures = noAttacks && (pos.ep_square() == SQ_NONE) && !pos.has_pawn_on_7th(us);
+  bool noCaptures =    ei
+                   && (ei->attackedBy[us][0] & pos.pieces_of_color(them)) == 0
+                   && !ei->mi->specialized_eval_exists()
+                   && (pos.ep_square() == SQ_NONE)
+                   && !pos.has_pawn_on_7th(us);

 
   if (p.is_check())
       phaseIndex = EvasionsPhaseIndex;
 
   if (p.is_check())
       phaseIndex = EvasionsPhaseIndex;


@@ -93,7 +96,6 @@ MovePicker::MovePicker(const Position& p, bool pv, Move ttm,
   else
       phaseIndex = (noCaptures ? NoMovesPhaseIndex : QsearchWithoutChecksPhaseIndex);
 
   else
       phaseIndex = (noCaptures ? NoMovesPhaseIndex : QsearchWithoutChecksPhaseIndex);
 

-

   dc = p.discovered_check_candidates(us);
   pinned = p.pinned_pieces(p.side_to_move());
 
   dc = p.discovered_check_candidates(us);
   pinned = p.pinned_pieces(p.side_to_move());