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Simplify code for pinaware SEE

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This is the most compact and neatest version
is was able to produce.

On normal builds I have a small slowdown:
normal builds base vs. simplification (gcc 4.8.1 Win7-64 i7-3770 @ 3.4GHz x86-64-modern)
Results for 20 tests for each version:

        Base      Test      Diff
Mean    1974744   1969333   5411
StDev   11825     10281     5874
p-value: 0,178
speedup: -0,003

On pgo-builds however I measure a nice 1.1% speedup

pgo-builds base vs. simplification
Results for 20 tests for each version:

        Base      Test      Diff
Mean    1974119   1995444   -21325
StDev   8703      5717      4623
p-value: 1
speedup: 0,011

No functional change.
This commit is contained in:
Guenther Demetz
2016-09-12 14:30:52 +02:00
committed by Marco Costalba
parent 90ce24b11e
commit ace8e951d7
1 changed files with 10 additions and 14 deletions
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24
src/position.cpp
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@@ -997,20 +997,17 @@ Value Position::see(Move m) const {
// If the opponent has no attackers we are finished // If the opponent has no attackers we are finished
stm = ~stm; stm = ~stm;
stmAttackers = attackers & pieces(stm); stmAttackers = attackers & pieces(stm);
if (!stmAttackers) occupied ^= to; // For the case when captured piece is a pinner
return swapList[0];
// Don't allow pinned pieces to attack as long all pinners (this includes also // Don't allow pinned pieces to attack as long all pinners (this includes also
// potential ones) are on their original square. When a pinner moves to the // potential ones) are on their original square. When a pinner moves to the
// exchange-square or get captured on it, we fall back to standard SEE behaviour. // exchange-square or get captured on it, we fall back to standard SEE behaviour.
else if ( (stmAttackers & st->blockersForKing[stm]) if ( (stmAttackers & pinned_pieces(stm))
&& ((st->pinnersForKing[stm] & (occupied ^ (occupied & to))) == st->pinnersForKing[stm])) && (st->pinnersForKing[stm] & occupied) == st->pinnersForKing[stm])
{ stmAttackers &= ~pinned_pieces(stm);
// Pinned pieces can't attack so remove them from attackers
stmAttackers ^= (stmAttackers & st->blockersForKing[stm]); if (!stmAttackers)
if (!stmAttackers) return swapList[0];
return swapList[0];
}
// The destination square is defended, which makes things rather more // The destination square is defended, which makes things rather more
// difficult to compute. We proceed by building up a "swap list" containing // difficult to compute. We proceed by building up a "swap list" containing
@@ -1030,10 +1027,9 @@ Value Position::see(Move m) const {
captured = min_attacker<PAWN>(byTypeBB, to, stmAttackers, occupied, attackers); captured = min_attacker<PAWN>(byTypeBB, to, stmAttackers, occupied, attackers);
stm = ~stm; stm = ~stm;
stmAttackers = attackers & pieces(stm); stmAttackers = attackers & pieces(stm);
if ( stmAttackers if ( (stmAttackers & pinned_pieces(stm))
&& (stmAttackers & st->blockersForKing[stm]) && (st->pinnersForKing[stm] & occupied) == st->pinnersForKing[stm])
&& ((st->pinnersForKing[stm] & (occupied ^ (occupied & to))) == st->pinnersForKing[stm])) stmAttackers &= ~pinned_pieces(stm);
stmAttackers ^= (stmAttackers & st->blockersForKing[stm]);
++slIndex; ++slIndex;