gcc/gcc/testsuite/gcc.target/i386/pr39162.c

/* { dg-do compile } */
/* { dg-options "-O2 -msse2 -mno-avx" } */

typedef long long __m256i __attribute__ ((__vector_size__ (32), __may_alias__));

__m256i
bar (__m256i x) /* { dg-warning "AVX" "" } */
{
  return x;
}