From ba57777d7d25f8fa1f1c951ec56e01b7f1207d9b Mon Sep 17 00:00:00 2001
From: Liang Ma <liangma@bytedance.com>
Date: Tue, 20 Jul 2021 14:36:45 +0100
Subject: [PATCH] build: check for broken AVX512 compiler support
GCC 6.3.0 has a known bug which related to _mm512_extracti64x4_epi64.
Please reference https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82887
Some DPDK PMD AVX512 version heavily use _mm512_extracti64x4_epi6,
which cause building failure with debug buildtype.
Therefore, it's helpful to check if compiler work with
_mm512_extracti64x4_epi6.
This patch check the compiler compile result against the test code
snippet. If the checking is failed then disable AVX512.
Bugzilla ID: 717
Fixes: e6a6a138919f ("net/i40e: add AVX512 vector path")
Fixes: 808a17b3c1e6 ("net/ice: add Rx AVX512 offload path")
Fixes: 4b64ccb328c9 ("net/iavf: fix VLAN extraction in AVX512 path")
Cc: stable@dpdk.org
Reported-by: Liang Ma <liangma@liangbit.com>
Signed-off-by: Liang Ma <liangma@bytedance.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
---
config/x86/meson.build | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/config/x86/meson.build b/config/x86/meson.build
index b9348c44de..704ba3db56 100644
--- a/config/x86/meson.build
+++ b/config/x86/meson.build
@@ -10,6 +10,19 @@ if not is_windows
endif
endif
+# check if compiler is working with _mm512_extracti64x4_epi64
+# Ref: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82887
+if cc.has_argument('-mavx512f')
+ code = '''#include <immintrin.h>
+ void test(__m512i zmm){
+ __m256i ymm = _mm512_extracti64x4_epi64(zmm, 0);}'''
+ result = cc.compiles(code, args : '-mavx512f', name : 'AVX512 checking')
+ if result == false
+ machine_args += '-mno-avx512f'
+ warning('Broken _mm512_extracti64x4_epi64, disabling AVX512 support')
+ endif
+endif
+
# we require SSE4.2 for DPDK
if cc.get_define('__SSE4_2__', args: machine_args) == ''
message('SSE 4.2 not enabled by default, explicitly enabling')
--
2.39.5