official-stockfish/Stockfish — pull request #146 by mcostalba (2014-12-07 08:56:38+00:00)
Title: Calculate pawnSpan on the fly

Avoid storing it in pawns hash entry but
calculate it when needed (only in bishop
ending logic).

It is also immediately clear what pawn_span()
does.

While there, renamed pawnsOnSquares to make
it clear is a counter.

No measurable speed difference.

No functional change.