"Van Haaren, Harry" <[email protected]> writes: >> -----Original Message----- >> From: Eelco Chaudron <[email protected]> >> Sent: Wednesday, July 14, 2021 10:12 AM >> To: Amber, Kumar <[email protected]>; Aaron Conole >> <[email protected]> >> Cc: [email protected]; [email protected]; [email protected]; Van >> Haaren, >> Harry <[email protected]>; Ferriter, Cian <[email protected]>; >> Stokes, Ian <[email protected]> >> Subject: Re: [v11 10/11] dpif-netdev/mfex: Add AVX512 based optimized >> miniflow >> extract > > <snip> > >> > + /* Permute the packet layout into miniflow blocks shape. >> > + * As different AVX512 ISA levels have different implementations, >> > + * this specializes on the "use_vbmi" attribute passed in. >> > + */ >> > + __m512i v512_zeros = _mm512_setzero_si512(); >> > + __m512i v_blk0 = v512_zeros; >> >> Although I did ACK this patchset, running make clang-analyzer, gave me the >> following warning, which should be fixed: >> >> lib/dpif-netdev-extract-avx512.c:476:17: warning: Value stored to 'v_blk0' >> during its >> initialization is never read >> __m512i v_blk0 = v512_zeros; >> ^~~~~~ ~~~~~~~~~~ >> 1 warning generated. > > Ah interesting, indeed its never read. Its also a "zeroed" register, so it > has no runtime > performance impact. (Magic of OoO execution, combined with register renaming > :) > > The fix is simply to remove the " = v512_zeros;" part, resulting in this decl > of the variable from > __m512i v_blk0 = v512_zeros; > to > __m512i v_blk0; > > Will be included in v11. > > >> Aaron, would it be possible to add a clang-analyzer run to the zero robot to >> catch >> newly introduced warnings? > > That'd be cool. I presume that a "scan-build" prefix to the build command is > all that's > needed, as usually the case with clang analyzer. Reproduced the above error > using > scan-build, so that seems to work :)
If it's simple enough, sure. Patch inc. > Regards, -Harry > > <snip remaining patch> _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
