[Bug target/120528] Optimize zero extend to TImode when value is in a VSX register on power10

[segher at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120528

--- Comment #2 from Segher Boessenkool <segher at gcc dot gnu.org> ---
And you can always use mtvsrdd d,0,s (which uses literal 0 as first source,
not GPR0).  In RTL that canonically is written as a zero_extend.