[Bug target/94343] [10 Regression] invalid AVX512VL vpternlogd instruction emitted for -march=knl

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94343

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jbeulich at suse dot com,
                   |                            |marxin at gcc dot gnu.org
   Last reconfirmed|                            |2020-03-26
     Ever confirmed|0                           |1
   Target Milestone|---                         |10.0
             Status|UNCONFIRMED                 |NEW
           Priority|P3                          |P1
      Known to work|                            |9.3.0
      Known to fail|                            |10.0

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
You are right, AVX512VL is not supported with knl.
It started with r10-2016-gff8f129bc2f57fdf:

        vpternlogd      $0x55, %xmm0, %xmm0, %xmm0
        vpcmpeqd        %xmm1, %xmm1, %xmm1
        vpandn  %xmm1, %xmm0, %xmm0
        ret

before the revision we emitted:

        vpcmpeqd        %xmm1, %xmm1, %xmm1
        vpxor   %xmm1, %xmm0, %xmm0
        vpcmpeqd        %xmm1, %xmm1, %xmm1
        vpandn  %xmm1, %xmm0, %xmm0
        ret