Allow a static evaluation to overwrite an exsisting entry

The idea here is that if we cut-off after a stand pat the
already exsisting TT entry was not usable with current
beta, so overwrite anyway.

After 999 games at 1+0
Mod vs Orig +173 =665 -161  + 4 ELO

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

diff --git a/src/tt.cpp b/src/tt.cpp
index a2ad42d0e54f7af87e53b75fca03eb6a300da340..c10f2e447f724ff3ccff4a6aabfc3e79b0738e9b 100644 (file)
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -121,10 +121,6 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d,
   {
       if (!tte->key() || tte->key() == posKey32) // empty or overwrite old
       {
-          // Do not overwrite when new type is VALUE_TYPE_EV_LO
-          if (tte->key() && t == VALUE_TYPE_EV_LO)
-              return;
-
           // Preserve any exsisting ttMove
           if (m == MOVE_NONE)
               m = tte->move();