[Bug target/118166] simple bit operations for __int128 do not use vector operations/registers

[gero.peterhoff at gmx dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118166

--- Comment #4 from Gero <gero.peterhoff at gmx dot net> ---
Changing the register sets is of course a problem. But u/int128 could also be
realized in xmm ?
- Addition/subtraction can be implemented efficiently (see attachemant).
- For multiplications/shl/shr/... this should also be possible ?
- Division is a separate function.

On other ISAs these problems may not occur and the operations can be
implemented better/more efficiently.
But you can judge this better than I can.

Merry Christmas
Gero