[dpdk-dev] [PATCH v3] build: disable gcc AVX512F support

[Yongseok Koh <yskoh@mellanox.com>]

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

This disables AVX512F support of gcc by adding -mno-avx512f if it is
disabled in DPDK (CONFIG_RTE_ENABLE_AVX512=n).

This does not apply to the meson build as that doesn't have such an option
but always enable AVX512F whenever supported.

Bugzilla ID: 97

Cc: stable@dpdk.org

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

v3:
* use AUTO_CPUFLAGS instead of redundant check for gcc
* remove the change from meson build

v2:
* disable the flag only in case of gcc

 mk/rte.cpuflags.mk | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/mk/rte.cpuflags.mk b/mk/rte.cpuflags.mk
index 43ed84155b..c3291b17a1 100644
--- a/mk/rte.cpuflags.mk
+++ b/mk/rte.cpuflags.mk
@@ -68,6 +68,11 @@ 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)
+MACHINE_CFLAGS += -mno-avx512f
+endif
 endif
 endif
 
-- 
2.11.0