From cc9d503ddea998890112efd08fae3705f2727e37 Mon Sep 17 00:00:00 2001
From: syzygy1 <3028851+syzygy1@users.noreply.github.com>
Date: Sat, 22 Aug 2020 13:36:34 +0200
Subject: [PATCH 1/1] Skip the alignment bug workaround for Clang

Clang-10.0.0 poses as gcc-4.2:

$ clang++ -E -dM - </dev/null | grep GNUC

This means that Clang is using the workaround for the alignment bug of gcc-8
even though it does not have the bug (as far as I know).

This patch should speed up AVX2 and AVX512 compiles on Windows (when using Clang),
because it disables (for Clang) the gcc workaround we had introduced in this commit:
https://github.com/official-stockfish/Stockfish/commit/875183b310a8249922c2155e82cb4cecfae2097e

closes https://github.com/official-stockfish/Stockfish/pull/3050

No functional change.
---
 src/nnue/nnue_common.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/nnue/nnue_common.h b/src/nnue/nnue_common.h
index 4c93e3d1..a9d8e5af 100644
--- a/src/nnue/nnue_common.h
+++ b/src/nnue/nnue_common.h
@@ -47,7 +47,7 @@
 //       compiled with older g++ crashes because the output memory is not aligned
 //       even though alignas is specified.
 #if defined(USE_AVX2)
-#if defined(__GNUC__ ) && (__GNUC__ < 9) && defined(_WIN32)
+#if defined(__GNUC__ ) && (__GNUC__ < 9) && defined(_WIN32) && !defined(__clang__)
 #define _mm256_loadA_si256  _mm256_loadu_si256
 #define _mm256_storeA_si256 _mm256_storeu_si256
 #else
@@ -57,7 +57,7 @@
 #endif
 
 #if defined(USE_AVX512)
-#if defined(__GNUC__ ) && (__GNUC__ < 9) && defined(_WIN32)
+#if defined(__GNUC__ ) && (__GNUC__ < 9) && defined(_WIN32) && !defined(__clang__)
 #define _mm512_loadA_si512   _mm512_loadu_si512
 #define _mm512_storeA_si512  _mm512_storeu_si512
 #else
-- 
2.39.2