Optimize an expression in endgame.cpp

protonspring · snicolet · commit fc3af7c4fbea · 2018-06-11T10:22:55.000+02:00
I believe using foward_file_bb() here is fewer instructions. a) Fewer instructions and probably more clear (debatable). b) Possible that a lookup is slower than a few local operations, but the forward_file_bb table is probably used often enough that it is always cached. Passed LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 21004 W: 4263 L: 4141 D: 12600 http://tests.stockfishchess.org/tests/view/5b1cad830ebc5902ab9c6239 Closes #1644 No functional change.
diff --git a/src/endgame.cpp b/src/endgame.cpp
@@ -214,7 +214,7 @@ Value Endgame<KRKP>::operator()(const Position& pos) const {
   Value result;
 
   // If the stronger side's king is in front of the pawn, it's a win
-  if (wksq < psq && file_of(wksq) == file_of(psq))
+  if (forward_file_bb(WHITE, wksq) & psq)
       result = RookValueEg - distance(wksq, psq);
 
   // If the weaker side's king is too far from the pawn and the rook,
