[Bug libstdc++/120428] [15/16 regression] Suboptimal autovec involving blocked permutation and std::copy

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120428

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The library code should be exactly equivalent, except for being slightly
simpler (one level of function call has been inlined into its caller now) and
doing:

  ptr += n;
  return ptr;

instead of:

  return ptr + n;

Otherwise, I see no differences and so no reason the compiler can't optimize it
identically.