Stockfish 1.6.1

Workaround a gcc optimization bug.

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

src/Makefile

@@ -25,8 +25,11 @@ EXE = stockfish
 ### ==========================================================================
 ### Compiler speed switches for both GCC and ICC. These settings are generally
 ### fast on a broad range of systems, but may be changed experimentally
+###
+### NOTE: Some versions of gcc miscompile value.h with -O2 or -O3, this is the
+### safe setup, try changing to -O3 or -O2 and verify it works for you.
 ### ==========================================================================
-GCCFLAGS = -O3 -msse
+GCCFLAGS = -O1 -msse
 ICCFLAGS = -fast -msse
 ICCFLAGS-OSX = -fast -mdynamic-no-pic
 

src/misc.cpp

@@ -50,7 +50,7 @@ using namespace std;
 /// Version number. If this is left empty, the current date (in the format
 /// YYMMDD) is used as a version number.
 
-static const string EngineVersion = "1.6";
+static const string EngineVersion = "1.6.1";
 static const string AppName = "Stockfish";
 static const string AppTag  = "";
 

src/position.cpp

@@ -671,7 +671,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
     Key pawnKey, materialKey;
     int castleRights, rule50, pliesFromNull;
     Square epSquare;
-    Value value;
+    Score value;
     Value npMaterial[2];
   };
 

src/value.h

@@ -52,8 +52,9 @@ enum Value {
 };
 
 
-/// Score struct keeps a midgame and an endgame value in a single
+/// Score enum keeps a midgame and an endgame value in a single
-/// ScoreValue 64 bit union.
+/// integer (enum), first LSB 16 bits are used to store endgame
+/// value, while upper bits are used for midgame value.
 
 enum Score {};