Package: gcc Version: 2:2.95.4-9 Severity: important Compiling the current gnuchess source fails with this gcc (current woody) and optimization set to -O2. The reason seems to be that statements are not correctly serialized. Unfortunately I am not an expert in PPC assembler but here is the code which breaks (modified from gnuchess source file src/move.c, somewhat shortened). Removing the "inline" keyword generates correct code with -O2. However, in the original source, clear_and_set_bit() is just part of UnmakeMove(), as well as of MakeMove(). So, the following should be (even more than) the relevant part.
typedef unsigned long long BitBoard; #define SETBIT(b,i) ((b) |= BitPosArray[i]) #define CLEARBIT(b,i) ((b) &= NotBitPosArray[i]) #define TOSQ(a) ((a) & 0x003F) #define FROMSQ(a) ((a >> 6) & 0x003F) inline void clear_and_set_bit(BitBoard *a, short f, short t) { CLEARBIT (*a, f); SETBIT (*a, t); } void UnmakeMove (short side, int *move) { BitBoard *a; short f, t, fpiece, cpiece; short xside; side = 1^side; xside = 1^side; f = FROMSQ(*move); t = TOSQ(*move); fpiece = cboard[t]; a = &board.b[side][fpiece]; clear_and_set_bit(a, t, f); /* continues... */ } So MakeMove() has about the same structure, except of course it switches the roles of t and f. Now the gnuchess move generation algorithm generates all possible moves, makes them, and unmakes them again. With inlining and -O2 however, it seems that making and unmaking of moves is not serialized, so that after trying out all pawn moves from the beginning position, white has a pawn on every square between the second and fourth row. If someone really wants, I can supply the assembler files move.s for -O1 (correct code) and -O2 (incorrect), together with the C source. Lukas