From ced0311890add58ab516b9c19608cbd1e1f295ed Mon Sep 17 00:00:00 2001
From: Linmiao Xu <linmiao.xu@gmail.com>
Date: Tue, 30 May 2023 18:24:54 -0400
Subject: [PATCH] Remove static eval threshold for extensions when giving check

Passed non-regression STC:
https://tests.stockfishchess.org/tests/view/647685d54a36543c4c9f4f2a
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 114688 W: 30701 L: 30571 D: 53416
Ptnml(0-2): 336, 12708, 31136, 12818, 346

Passed non-regression LTC:
https://tests.stockfishchess.org/tests/view/64774b02b81f005b572de770
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 107310 W: 28920 L: 28796 D: 49594
Ptnml(0-2): 33, 10427, 32621, 10531, 43

closes https://github.com/official-stockfish/Stockfish/pull/4599

bench 2597974
---
 src/search.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/search.cpp b/src/search.cpp
index 1e82203a..4365b215 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1085,7 +1085,8 @@ moves_loop: // When in check, search starts here
           }
 
           // Check extensions (~1 Elo)
-          else if (   givesCheck && depth > 8)
+          else if (   givesCheck
+                   && depth > 9)
               extension = 1;
 
           // Quiet ttMove extensions (~1 Elo)