[Bug target/122014] (AArch64) Optimize 8-bit and 16-bit popcount as special cases

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122014

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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           Keywords|                            |missed-optimization

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So for the 8bit and 16bit modes. Basically comes down to the other elements of
the vector are dont care.

In the case of a load, zero extend is the best but in the case of moving from a
registerdup is better.