[Bug math/21967] New: When 512-bit AVX2 wrapper functions in mathvec are used?

["hjl.tools at gmail dot com" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=21967

            Bug ID: 21967
           Summary: When 512-bit AVX2 wrapper functions in mathvec are
                    used?
           Product: glibc
           Version: 2.27
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
          Assignee: unassigned at sourceware dot org
          Reporter: hjl.tools at gmail dot com
                CC: andrew.n.senkevich at gmail dot com
  Target Milestone: ---
            Target: x86-64

521-bit AVX2 wrapper functions in mathvec, likesvml_d_log8_core-avx2.S, have

#define _ZGVeN8v_log _ZGVeN8v_log_avx2_wrapper
#include "../svml_d_log8_core.S"

It is used by svml_d_log8_core.c with

static inline void *
IFUNC_SELECTOR (void)
{
  const struct cpu_features* cpu_features = __get_cpu_features ();

  if (CPU_FEATURES_ARCH_P (cpu_features, AVX512DQ_Usable))
    return OPTIMIZE (skx);

  if (CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable))
    return OPTIMIZE (knl);

  return OPTIMIZE (avx2_wrapper);
}

So if AVX512 isn't available, _ZGVeN8v_log_avx2_wrapper will be used.  It
is compiled into

0000000000000000 <_ZGVeN8v_log_avx2_wrapper>:
   0:   55                      push   %rbp
   1:   48 89 e5                mov    %rsp,%rbp
   4:   48 83 e4 c0             and    $0xffffffffffffffc0,%rsp
   8:   48 81 ec 80 00 00 00    sub    $0x80,%rsp
   f:   62 f1 7c 48 11 04 24    vmovups %zmm0,(%rsp)
  16:   c5 fd 10 04 24          vmovupd (%rsp),%ymm0
  1b:   e8 00 00 00 00          callq  20 <_ZGVeN8v_log_avx2_wrapper+0x20>     
1c: R_X86_64_PC32       __GI__ZGVdN4v_log-0x4
  20:   c5 fd 11 44 24 40       vmovupd %ymm0,0x40(%rsp)
  26:   c5 fd 10 44 24 20       vmovupd 0x20(%rsp),%ymm0
  2c:   e8 00 00 00 00          callq  31 <_ZGVeN8v_log_avx2_wrapper+0x31>     
2d: R_X86_64_PC32       __GI__ZGVdN4v_log-0x4
  31:   c5 fd 11 44 24 60       vmovupd %ymm0,0x60(%rsp)
  37:   62 f1 7c 48 10 44 24 01         vmovups 0x40(%rsp),%zmm0
  3f:   48 89 ec                mov    %rbp,%rsp
  42:   5d                      pop    %rbp
  43:   c3                      retq   

But

   f:   62 f1 7c 48 11 04 24    vmovups %zmm0,(%rsp)

is an AVX512F instruction.  How is it supposed to work?

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