Re: [PATCH v3] net: fix build error with clang

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Tue, Sep 27, 2016 at 05:24:35PM +0000, Chen, Jing D wrote:
> > On Mon, Sep 26, 2016 at 12:29:13PM +0800, Yuanhan Liu wrote:
> > > Interestingly, clang and gcc has different prototype for _mm_prefetch().
> > > For gcc, we have
> > >
> > >    _mm_prefetch (const void *__P, enum _mm_hint __I)
> > >
> > > While for clang, it's
> > >
> > >    #define _mm_prefetch(a, sel) (__builtin_prefetch((void *)(a), 0,
> > > (sel)))
> > >
> > > That's how the following error comes with clang:
> > >
> > >    error: cast from 'const void *' to 'void *' drops const qualifier
> > >    [-Werror,-Wcast-qual]
> > >            _mm_prefetch((const void *)rused, _MM_HINT_T0);
> > >    /usr/lib/llvm-3.8/bin/../lib/clang/3.8.0/include/xmmintrin.h:684:58:
> > >    note: expanded from macro '_mm_prefetch'
> > >             #define _mm_prefetch(a, sel) (__builtin_prefetch((void *)(a),
> > >                                           0, (sel)))
> > >
> > > What's weird is that the build was actaully Okay before. I met it
> > > while apply Jerin's vector support for ARM patch set: he just move
> > > this peiece of code to another file, nothing else changed.
> > >
> > > This patch fix the issue when Jerin's patchset is applied. Thus, I
> > > think it's still needed.
> > >
> > > Similarly, make the same change to other _mm_prefetch users, just in
> > > case this weird issue shows up again somehow later.
...
> > > Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
> Acked-by: Jing Chen <jing.d.chen@intel.com>

Mark, thank you!

Applied to dpdk-next-virtio.

	--yliu