When building using an older compiler that doesn't support avx512,
we are adding '-mno-avx512f' into the command line, which results
with a build failure:
gcc: error: unrecognized command line option '-mno-avx512f'
This is a case, for example, while trying to build OVS with GCC 4.8.
Fix that by avoiding binutils check when compiler doesn't understand
-mavx512f.
Later in the call chain there is also an explicit check for -mavx512f
support, but it will just use the cached result, so it's not a problem.
Fixes: 930f135f5ddc ("configure: explicitly disable avx512 if bintuils check
fails")
Signed-off-by: Ilya Maximets <[email protected]>
---
m4/openvswitch.m4 | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/m4/openvswitch.m4 b/m4/openvswitch.m4
index 6d41ffc44..060070475 100644
--- a/m4/openvswitch.m4
+++ b/m4/openvswitch.m4
@@ -475,7 +475,9 @@ dnl The checking of binutils funcationality instead of LD
version is similar
dnl to as how DPDK proposes to solve this issue:
dnl http://patches.dpdk.org/patch/71723/
AC_DEFUN([OVS_CHECK_BINUTILS_AVX512],
- [AC_CACHE_CHECK(
+ [OVS_CHECK_CC_OPTION(
+ [-mavx512f],
+ [AC_CACHE_CHECK(
[binutils avx512 assembler checks passing],
[ovs_cv_binutils_avx512_good],
[dnl Assemble a short snippet to test for issue in "build-aux" dir:
@@ -496,7 +498,8 @@ AC_DEFUN([OVS_CHECK_BINUTILS_AVX512],
else
dnl non x86_64 architectures don't have avx512, so not affected
ovs_cv_binutils_avx512_good=no
- fi])
+ fi])],
+ [ovs_cv_binutils_avx512_good=no])
if test "$ovs_cv_binutils_avx512_good" = yes; then
AC_DEFINE([HAVE_LD_AVX512_GOOD], [1],
[Define to 1 if binutils correctly supports AVX512.])
--
2.51.0
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