Micro-optimize color_of()

In almost all cases we already know in advance that
color_of() argument is different from NO_PIECE.

So avoid the check for NO_PIECE in color_of() and
test at caller site in the very few places where
this case could occur.

As a nice side effect, this patch fixes a (bogus)
warning under some versions of gcc.

No functional change.

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

diff --git a/src/position.cpp b/src/position.cpp
index a0d5730c4e75a427da26930aeed3df681d6e1f49..37b5c049cadd2152b6fdccaee44a87d0f57df315 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -561,7 +561,7 @@ bool Position::is_pseudo_legal(const Move m) const {
       return false;
 
   // The destination square cannot be occupied by a friendly piece
       return false;
 
   // The destination square cannot be occupied by a friendly piece

-  if (color_of(piece_on(to)) == us)
+  if (piece_on(to) != NO_PIECE && color_of(piece_on(to)) == us)

       return false;
 
   // Handle the special case of a pawn move
       return false;
 
   // Handle the special case of a pawn move


@@ -587,7 +587,7 @@ bool Position::is_pseudo_legal(const Move m) const {
       case DELTA_SE:
       // Capture. The destination square must be occupied by an enemy
       // piece (en passant captures was handled earlier).
       case DELTA_SE:
       // Capture. The destination square must be occupied by an enemy
       // piece (en passant captures was handled earlier).

-      if (color_of(piece_on(to)) != them)
+      if (piece_on(to) == NO_PIECE || color_of(piece_on(to)) != them)

           return false;
 
       // From and to files must be one file apart, avoids a7h5
           return false;
 
       // From and to files must be one file apart, avoids a7h5


@@ -772,7 +772,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
   PieceType capture = type_of(m) == ENPASSANT ? PAWN : type_of(piece_on(to));
 
   assert(color_of(piece) == us);
   PieceType capture = type_of(m) == ENPASSANT ? PAWN : type_of(piece_on(to));
 
   assert(color_of(piece) == us);

-  assert(color_of(piece_on(to)) != us);
+  assert(piece_on(to) == NO_PIECE || color_of(piece_on(to)) == them);

   assert(capture != KING);
 
   if (capture)
   assert(capture != KING);
 
   if (capture)

diff --git a/src/types.h b/src/types.h
index 9b36fd89fde9f9505dc54a2093bab49711cbf651..99567bd7e22a608de7ca91a16d81058112661624 100644 (file)
--- a/src/types.h
+++ b/src/types.h
@@ -35,6 +35,7 @@
 ///               | only in 64-bit mode. For compiling requires hardware with
 ///               | popcnt support.
 
 ///               | only in 64-bit mode. For compiling requires hardware with
 ///               | popcnt support.
 

+#include <cassert>

 #include <cctype>
 #include <climits>
 #include <cstdlib>
 #include <cctype>
 #include <climits>
 #include <cstdlib>


@@ -391,7 +392,8 @@ inline PieceType type_of(Piece p)  {
 }
 
 inline Color color_of(Piece p) {
 }
 
 inline Color color_of(Piece p) {

-  return p == NO_PIECE ? NO_COLOR : Color(p >> 3);
+  assert(p != NO_PIECE);
+  return Color(p >> 3);

 }
 
 inline bool is_ok(Square s) {
 }
 
 inline bool is_ok(Square s) {