[Bug tree-optimization/92243] Missing "auto-vectorization" of char array reversal using x86 scalar bswap when SIMD pshufb isn't available

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92243

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Even lowering of VEC_PERM for this case:
#define vector __attribute__((vector_size(16)))

vector char f(vector char a)
{
  a = __builtin_shufflevector   (a, a,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
  return a;
}

---- CUT ---
could be done just as 2 (or 4) extraction followed by a bswap if the target
does not support the VEC_PERM too.