Assorted trivial cleanups (July 2019)

No functional change

AUTHORS

@@ -11,6 +11,7 @@ Ajith Chandy Jose (ajithcj)
 Alain Savard (Rocky640)
 alayan-stk-2
 Alexander Kure
+Alexander Pagel (Lolligerhans)
 Ali AlZhrani (Cooffe)
 Andrew Grant (AndyGrant)
 Andrey Neporada (nepal)
@@ -82,6 +83,7 @@ Lub van den Berg (ElbertoOne)
 Luca Brivio (lucabrivio)
 Lucas Braesch (lucasart)
 Lyudmil Antonov (lantonov)
+Maciej Żenczykowski (zenczykowski)
 Matthew Lai (matthewlai)
 Matthew Sullivan
 Mark Tenzer (31m059)

src/bitboard.h

@@ -377,6 +377,8 @@ inline Square pop_lsb(Bitboard* b) {
 
 
 /// frontmost_sq() returns the most advanced square for the given color
-inline Square frontmost_sq(Color c, Bitboard b) { return c == WHITE ? msb(b) : lsb(b); }
+inline Square frontmost_sq(Color c, Bitboard b) {
+  return c == WHITE ? msb(b) : lsb(b);
+}
 
 #endif // #ifndef BITBOARD_H_INCLUDED

src/evaluate.cpp

@@ -505,9 +505,6 @@ namespace {
     // Enemies not strongly protected and under our attack
     weak = pos.pieces(Them) & ~stronglyProtected & attackedBy[Us][ALL_PIECES];
 
-    // Safe or protected squares
-    safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];
-
     // Bonus according to the kind of attacking pieces
     if (defended | weak)
     {
@@ -544,6 +541,14 @@ namespace {
 
     score += RestrictedPiece * popcount(b);
 
+    // Protected or unattacked squares
+    safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];
+
+    // Bonus for attacking enemy pieces with our relatively safe pawns
+    b = pos.pieces(Us, PAWN) & safe;
+    b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
+    score += ThreatBySafePawn * popcount(b);
+
     // Find squares where our pawns can push on the next move
     b  = shift<Up>(pos.pieces(Us, PAWN)) & ~pos.pieces();
     b |= shift<Up>(b & TRank3BB) & ~pos.pieces();
@@ -555,12 +560,6 @@ namespace {
     b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
     score += ThreatByPawnPush * popcount(b);
 
-    // Our safe or protected pawns
-    b = pos.pieces(Us, PAWN) & safe;
-
-    b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
-    score += ThreatBySafePawn * popcount(b);
-
     // Bonus for threats on the next moves against enemy queen
     if (pos.count<QUEEN>(Them) == 1)
     {

src/pawns.cpp

@@ -52,8 +52,8 @@ namespace {
 
   // Danger of enemy pawns moving toward our king by [distance from edge][rank].
   // RANK_1 = 0 is used for files where the enemy has no pawn, or their pawn
-  // is behind our king.
-  // [0][1-2] accommodate opponent pawn on edge (likely blocked by our king)
+  // is behind our king. Note that UnblockedStorm[0][1-2] accommodate opponent pawn
+  // on edge, likely blocked by our king.
   constexpr Value UnblockedStorm[int(FILE_NB) / 2][RANK_NB] = {
     { V( 89), V(-285), V(-185), V(93), V(57), V( 45), V( 51) },
     { V( 44), V( -18), V( 123), V(46), V(39), V( -7), V( 23) },
@@ -196,10 +196,10 @@ void Entry::evaluate_shelter(const Position& pos, Square ksq, Score& shelter) {
   for (File f = File(center - 1); f <= File(center + 1); ++f)
   {
       b = ourPawns & file_bb(f);
-      Rank ourRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
+      int ourRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
 
       b = theirPawns & file_bb(f);
-      Rank theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
+      int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
 
       int d = std::min(f, ~f);
       bonus += make_score(ShelterStrength[d][ourRank], 0);
@@ -234,7 +234,7 @@ Score Entry::do_king_safety(const Position& pos) {
   else while (pawns)
       minPawnDist = std::min(minPawnDist, distance(ksq, pop_lsb(&pawns)));
 
-  Score shelter = make_score(-VALUE_INFINITE, VALUE_ZERO);
+  Score shelter = make_score(-VALUE_INFINITE, 0);
   evaluate_shelter<Us>(pos, ksq, shelter);
 
   // If we can castle use the bonus after the castling if it is bigger
@@ -244,7 +244,7 @@ Score Entry::do_king_safety(const Position& pos) {
   if (pos.can_castle(Us | QUEEN_SIDE))
       evaluate_shelter<Us>(pos, relative_square(Us, SQ_C1), shelter);
 
-  return shelter - make_score(VALUE_ZERO, 16 * minPawnDist);
+  return shelter - make_score(0, 16 * minPawnDist);
 }
 
 // Explicit template instantiation

src/search.cpp

@@ -102,15 +102,16 @@ namespace {
     Move best = MOVE_NONE;
   };
 
-  // Breadcrumbs are used to mark nodes as being searched by a given thread.
+  // Breadcrumbs are used to mark nodes as being searched by a given thread
   struct Breadcrumb {
     std::atomic<Thread*> thread;
     std::atomic<Key> key;
   };
   std::array<Breadcrumb, 1024> breadcrumbs;
 
-  // ThreadHolding keeps track of which thread left breadcrumbs at the given node for potential reductions.
-  // A free node will be marked upon entering the moves loop, and unmarked upon leaving that loop, by the ctor/dtor of this struct.
+  // ThreadHolding structure keeps track of which thread left breadcrumbs at the given
+  // node for potential reductions. A free node will be marked upon entering the moves
+  // loop by the constructor, and unmarked upon leaving that loop by the destructor.
   struct ThreadHolding {
     explicit ThreadHolding(Thread* thisThread, Key posKey, int ply) {
        location = ply < 8 ? &breadcrumbs[posKey & (breadcrumbs.size() - 1)] : nullptr;
@@ -118,7 +119,7 @@ namespace {
        owning = false;
        if (location)
        {
-          // see if another already marked this location, if not, mark it ourselves.
+          // See if another already marked this location, if not, mark it ourselves
           Thread* tmp = (*location).thread.load(std::memory_order_relaxed);
           if (tmp == nullptr)
           {
@@ -133,7 +134,7 @@ namespace {
     }
 
     ~ThreadHolding() {
-       if (owning) // free the marked location.
+       if (owning) // Free the marked location
            (*location).thread.store(nullptr, std::memory_order_relaxed);
     }
 
@@ -908,7 +909,7 @@ moves_loop: // When in check, search starts from here
     moveCountPruning = false;
     ttCapture = ttMove && pos.capture_or_promotion(ttMove);
 
-    // Mark this node as being searched.
+    // Mark this node as being searched
     ThreadHolding th(thisThread, posKey, ss->ply);
 
     // Step 12. Loop through all pseudo-legal moves until no moves remain