Prune evasions when we can castle

A minor simplification.

STC:

LLR: 2.95 (-2.94,2.94) [-3.50,0.50]
Total: 67877 W: 12882 L: 12904 D: 42091

STC:

LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 20677 W: 4023 L: 3901 D: 12753

LTC:

LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 12221 W: 2022 L: 1888 D: 8311

Bench: 7911336

Resolves #326

diff --git a/src/search.cpp b/src/search.cpp
index f0c1bdd978e14fdc661c2a4041bb220fce343055..340ddfc1d97f68834ff88304a72bc398c13d4874 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1302,8 +1302,7 @@ moves_loop: // When in check and at SpNode search starts from here
       // Detect non-capture evasions that are candidates to be pruned
       evasionPrunable =    InCheck
                        &&  bestValue > VALUE_MATED_IN_MAX_PLY
-                       && !pos.capture(move)
-                       && !pos.can_castle(pos.side_to_move());
+                       && !pos.capture(move);
 
       // Don't search moves with negative SEE values
       if (  (!InCheck || evasionPrunable)