From: Marco Costalba <mcostalba@gmail.com>
Date: Wed, 4 Nov 2009 10:11:04 +0000 (+0100)
Subject: Speed up perft
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=483a2576185a8158bef8ac97bb013258afb1b64a

Speed up perft

There is no need to do / undo the move at the last ply

No functional change.

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

diff --git a/src/search.cpp b/src/search.cpp
index 3e4341c0..c323de5d 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -332,14 +332,19 @@ namespace {
 
 int perft(Position& pos, Depth depth)
 {
-    if (depth <= Depth(0)) // Replace with '<' to test also qsearch
-      return 1;
-
     Move move;
     MovePicker mp = MovePicker(pos, MOVE_NONE, depth, H);
     Bitboard dcCandidates = mp.discovered_check_candidates();
     int sum = 0;
 
+    // If we are at the last ply we don't need to do and undo
+    // the moves, just to count them.
+    if (depth <= OnePly) // Replace with '<' to test also qsearch
+    {
+        while ((move = mp.get_next_move()) != MOVE_NONE) sum++;
+        return sum;
+    }
+
     // Loop through all legal moves
     while ((move = mp.get_next_move()) != MOVE_NONE)
     {