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| author | Cian Ferriter <cian.ferriter@intel.com> | 2022-08-11 10:36:38 +0000 |
|---|---|---|
| committer | Ian Stokes <ian.stokes@intel.com> | 2022-08-12 09:52:20 +0100 |
| commit | ac1332216eb3a1857b942457e1b44a22512b092d (patch) | |
| tree | 5e98605fdc92d139bf0c406127cde10259d1d4cb /m4 | |
| parent | 39364e11dd2cf722a037de25705b352272173f21 (diff) | |
| download | openvswitch-ac1332216eb3a1857b942457e1b44a22512b092d.tar.gz | |
acinclude: Improve vpopcntdq build check.
Support for vpopcntdq instruction generation by the compiler was already
checked in the OVS_CHECK_AVX512 AC function by checking if the compiler
accepted the -mavx512vpopcntdq option. However, there can be situations
where the compiler supports vpopcntdq generation but the assembler
doesn't support the instruction.
The below OVS_CHECK_AVX512VPOPCNTDQ AC function will check for both
compiler and assembler support for the vpopcntdq instruction.
Fixes: cb1c64007734 ("acinclude: Add seperate checks for AVX512 ISA.")
Reported-by: Ian Stokes <ian.stokes@intel.com>
Signed-off-by: Cian Ferriter <cian.ferriter@intel.com>
Acked-by: Sunil Pai G <sunil.pai.g@intel.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
Diffstat (limited to 'm4')
| -rw-r--r-- | m4/openvswitch.m4 | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/m4/openvswitch.m4 b/m4/openvswitch.m4 index 6eef1fb35..b5be5842e 100644 --- a/m4/openvswitch.m4 +++ b/m4/openvswitch.m4 @@ -450,6 +450,35 @@ AC_DEFUN([OVS_CHECK_GCC_AVX512VL], [ AM_CONDITIONAL([HAVE_GCC_AVX512VL_GOOD], [test "$ovs_cv_gcc_avx512vl_good" = yes])]) +dnl Checks whether the build system implements the vpopcntdq instruction. The +dnl compiler and assembler each separately need to support vpopcntdq. In order +dnl to test the assembler with the below code snippet, set the optimization +dnl level of the function to "O0" so it won't be optimized away by the +dnl compiler. +AC_DEFUN([OVS_CHECK_AVX512VPOPCNTDQ], [ + AC_MSG_CHECKING([whether compiler correctly emits AVX512-VPOPCNTDQ]) + AC_COMPILE_IFELSE( + [AC_LANG_PROGRAM([#include <immintrin.h> + void + __attribute__((__target__("avx512vpopcntdq"))) + __attribute__((optimize("O0"))) + check_vpopcntdq(void) + { + __m512i v_test; + v_test = _mm512_popcnt_epi64(v_test); + }],[])], + [AC_MSG_RESULT([yes]) + ovs_cv_avx512vpopcntdq_good=yes], + [AC_MSG_RESULT([no]) + ovs_cv_avx512vpopcntdq_good=no]) + if test "$ovs_cv_avx512vpopcntdq_good" = yes; then + AC_DEFINE([HAVE_AVX512VPOPCNTDQ], [1], + [Define to 1 if the build system implements the vpopcntdq + instruction.]) + fi + AM_CONDITIONAL([HAVE_AVX512VPOPCNTDQ], + [test "$ovs_cv_avx512vpopcntdq_good" = yes])]) + dnl Checks for binutils/assembler known issue with AVX512. dnl Due to backports, we probe assembling a reproducer instead of checking dnl binutils version string. More details, including ASM dumps and debug here: |