[Bug tree-optimization/91940] __builtin_bswap16 loop optimization

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91940

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 46985
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46985&action=edit
gcc10-pr91940.patch

Full untested patch.