[Bug target/79932] New: _mm512_packus_epi32 does not compile under -O0

["carloscastro10 at hotmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79932

            Bug ID: 79932
           Summary: _mm512_packus_epi32 does not compile under -O0
           Product: gcc
           Version: 6.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: carloscastro10 at hotmail dot com
  Target Milestone: ---

The _mm512_packus_epi32 intrinsic compiles fine under -Og, -O2, -O3, but does
not compile under -O0. For a simple example consider the following code:

#include <immintrin.h>

__m512i packus(__m512i a)
{

  return _mm512_packus_epi32(a,a);
}

Try compiling with "-march=skylake-avx512 -O0". It will fail. However, under
-Og, -O2, or -O3 it will compile fine.