[Bug target/113858] `ldr s0/h0/b0` should be used to zero extend into the full register

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113858

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(set (reg:V4HI 105 [ _4 ])
    (vec_merge:V4HI (vec_duplicate:V4HI (reg:HI 106 [ *a_3(D) ]))
        (const_vector:V4HI [
                (const_int 0 [0]) repeated x4
            ])
        (const_int 1 [0x1])))