From 8a1b0f8b044ffbaf7341325de978d21382d7ef60 Mon Sep 17 00:00:00 2001
From: Linmiao Xu <linmiao.xu@gmail.com>
Date: Thu, 2 Apr 2026 20:28:12 +0200
Subject: [PATCH] Reorder NNUE accumulator evals

Makes eval calls more cache-friendly on a hot path.

Hints of a speedup found locally:
```
Result of  30 runs
==================
base (...ockfish-base) =    1754124  +/- 2887
test (...h-eval-order) =    1757848  +/- 2412
diff                   =      +3724  +/- 1368

speedup        = +0.0021
P(speedup > 0) =  1.0000

CPU: 16 x arm
Hyperthreading: off
```

Passed STC:
https://tests.stockfishchess.org/tests/view/69c84f3cf40d95b975597c21
LLR: 3.36 (-2.94,2.94) <0.00,2.00>
Total: 335840 W: 87022 L: 86257 D: 162561
Ptnml(0-2): 932, 36760, 91816, 37435, 977

closes https://github.com/official-stockfish/Stockfish/pull/6693

No functional change
---
 src/nnue/nnue_accumulator.cpp | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/nnue/nnue_accumulator.cpp b/src/nnue/nnue_accumulator.cpp
index 5922275d0..554060dd8 100644
--- a/src/nnue/nnue_accumulator.cpp
+++ b/src/nnue/nnue_accumulator.cpp
@@ -145,14 +145,13 @@ void AccumulatorStack::evaluate(const Position&                       pos,
     constexpr bool UseThreats = (Dimensions == TransformedFeatureDimensionsBig);
 
     evaluate_side<PSQFeatureSet>(WHITE, pos, featureTransformer, cache);
-
-    if (UseThreats)
-        evaluate_side<ThreatFeatureSet>(WHITE, pos, featureTransformer, cache);
-
     evaluate_side<PSQFeatureSet>(BLACK, pos, featureTransformer, cache);
 
     if (UseThreats)
+    {
+        evaluate_side<ThreatFeatureSet>(WHITE, pos, featureTransformer, cache);
         evaluate_side<ThreatFeatureSet>(BLACK, pos, featureTransformer, cache);
+    }
 }
 
 template<typename FeatureSet, IndexType Dimensions>