[ovs-dev] [PATCH] dpcls: fix build on compilers without AVX512-VPOPCNT

[Stokes, Ian]

> > -----Original Message-----
> > From: Van Haaren, Harry <harry.van.haaren at intel.com>
> > Sent: Thursday, July 29, 2021 5:55 PM
> > To: ovs-dev at openvswitch.org
> > Cc: Stokes, Ian <ian.stokes at intel.com>; Van Haaren, Harry
> > <harry.van.haaren at intel.com>
> > Subject: [PATCH] dpcls: fix build on compilers without AVX512-VPOPCNT
> >
> > This commit adds extra checks around the AVX-512 vpopcnt instruction
> > enabling, ensuring that in the function where the ISA is enabled the
> > compiler has also indicated its support for the ISA. This is achieved
> > by checking the __AVX512VPOPCNTDQ__ define, which the compiler sets if
> > it is capable of handling the vpopcnt instruction.
> >
> > If the compiler is not capable of handling vpopcnt, we fall back to
> > the emulated vpopcnt implementation.
> >
> > Reported-by: Ian Stokes <ian.stokes at intel.com>
> > Signed-off-by: Harry van Haaren <harry.van.haaren at intel.com>
> >
> > ---
> >
> > Based on a very old system with GCC 7, an issue was identified
> > where the compiler doesn't support the vpopcnt ISA, and resulted
> > in compilation failures.
> 
> Ping on this patch, would be good to get integrated on 2.16 and master to
> ensure Gcc7 builds correctly.

HI Harry,

Just testing this now.

Regards
Ian