[dpdk-dev] [PATCH v2] build: disable compiler AVX512F support

[Yongseok Koh]

This is a workaround to prevent a crash, which might be caused by
optimization of newer gcc (7.3.0) on Intel Skylake.

Bugzilla ID: 97

Cc: stable at dpdk.org

Signed-off-by: Yongseok Koh <yskoh at mellanox.com>
---

v2:
* disable the flag only in case of gcc

 config/x86/meson.build | 5 +++++
 mk/rte.cpuflags.mk     | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/config/x86/meson.build b/config/x86/meson.build
index 33efb5e547..8ddca0ea9f 100644
--- a/config/x86/meson.build
+++ b/config/x86/meson.build
@@ -47,6 +47,11 @@ endif
 if cc.get_define('__AVX512F__', args: march_opt) != ''
 	dpdk_conf.set('RTE_MACHINE_CPUFLAG_AVX512F', 1)
 	compile_time_cpuflags += ['RTE_CPUFLAG_AVX512F']
+else
+# disable AVX512F support of gcc as a workaround for Bug 97
+	if cc.get_id() == 'gcc' and cc.has_argument('-mavx512f')
+		machine_args += '-mno-avx512f'
+	endif
 endif
 
 dpdk_conf.set('RTE_CACHE_LINE_SIZE', 64)
diff --git a/mk/rte.cpuflags.mk b/mk/rte.cpuflags.mk
index 43ed84155b..a8c26fb011 100644
--- a/mk/rte.cpuflags.mk
+++ b/mk/rte.cpuflags.mk
@@ -68,6 +68,13 @@ endif
 ifneq ($(filter $(AUTO_CPUFLAGS),__AVX512F__),)
 ifeq ($(CONFIG_RTE_ENABLE_AVX512),y)
 CPUFLAGS += AVX512F
+else
+# disable AVX512F support of gcc as a workaround for Bug 97
+ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC),y)
+	ifeq ($(shell $(CC) --target-help | grep -q mavx512f && echo 1), 1)
+		MACHINE_CFLAGS += -mno-avx512f
+	endif
+endif
 endif
 endif
 
-- 
2.11.0