Retire eval optimization from null search

Simplify things preparing for further changes.

bench: 4983282

diff --git a/src/search.cpp b/src/search.cpp
index da20f15e3352964a596137a7f581e2e885b9e6ed..b538897944ba7d174e17fdded262d8ddb719f0f4 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1105,7 +1105,7 @@ split_point_start: // At split points actual search starts from here
     Key posKey;
     Move ttMove, move, bestMove;
     Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
-    bool givesCheck, enoughMaterial, evasionPrunable, fromNull;
+    bool givesCheck, enoughMaterial, evasionPrunable;
     Depth ttDepth;
 
     // To flag BOUND_EXACT a node with eval above alpha and no available moves
@@ -1114,7 +1114,6 @@ split_point_start: // At split points actual search starts from here
 
     ss->currentMove = bestMove = MOVE_NONE;
     ss->ply = (ss-1)->ply + 1;
-    fromNull = (ss-1)->currentMove == MOVE_NULL;
 
     // Check for an instant draw or maximum ply reached
     if (pos.is_draw<false, false>() || ss->ply > MAX_PLY)
@@ -1152,12 +1151,7 @@ split_point_start: // At split points actual search starts from here
     }
     else
     {
-        if (fromNull)
-        {
-            ss->staticEval = bestValue = -(ss-1)->staticEval;
-            ss->evalMargin = VALUE_ZERO;
-        }
-        else if (tte)
+        if (tte)
         {
             assert(tte->static_value() != VALUE_NONE || Threads.size() > 1);
 
@@ -1205,7 +1199,6 @@ split_point_start: // At split points actual search starts from here
       if (   !PvNode
           && !InCheck
           && !givesCheck
-          && !fromNull
           &&  move != ttMove
           &&  enoughMaterial
           &&  type_of(move) != PROMOTION