[Bug target/115756] default tuning for x86_64 produces shifts for `*240`

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115756

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |x86_64-*-*

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
it probably very much depends on surrounding code and port utilization but for
generic tuning I'd lean towards shift+add because for example Intel E-cores
have a slow imul.