Remove a redundant check in passed pawn eval

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index a069cf404be6d012a7ac129c4386b0c3a1721586..176806976bb4234105d25826a973097537984b4a 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -641,10 +641,10 @@ bool Position::move_is_check(Move m, const CheckInfo& ci) const {
       }
   }
 
-  // En passant capture with check?  We have already handled the case
+  // En passant capture with check ? We have already handled the case
   // of direct checks and ordinary discovered check, the only case we
-  // need to handle is the unusual case of a discovered check through the
-  // captured pawn.
+  // need to handle is the unusual case of a discovered check through
+  // the captured pawn.
   if (move_is_ep(m))
   {
       Square capsq = make_square(square_file(to), square_rank(from));
@@ -1307,11 +1307,11 @@ int Position::see_sign(Move m) const {
   Square from = move_from(m);
   Square to = move_to(m);
 
-  // Early return if SEE cannot be negative because capturing piece value
-  // is not bigger then captured one.
-  if (   midgame_value_of_piece_on(from) <= midgame_value_of_piece_on(to)
-      && type_of_piece_on(from) != KING)
-         return 1;
+  // Early return if SEE cannot be negative because captured piece value
+  // is not less then capturing one. Note that king moves always return
+  // here because king midgame value is set to 0.
+  if (midgame_value_of_piece_on(to) >= midgame_value_of_piece_on(from))
+      return 1;
 
   return see(from, to);
 }