[Bug tree-optimization/101139] Unable to remove double byteswap in fast path

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101139

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
One odd thing is that while __builtin_bswap16 is declared as taking an uint16
argument the frontend promotes it to 'int' and that stays that way in GIMPLE:

  _16 = (short unsigned int) f$ab_14;
  _17 = (int) _16;
  _18 = __builtin_bswap16 (_17);