https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103897
--- Comment #4 from Hongtao.liu <crazylht at gmail dot com> ---
For 2), it seems to be a generic optimization to optimize
(set (mem:V4SI (reg:DI 95) [0 *dst_7(D)+0 S16 A128])
(ashiftrt:V4SI (subreg:V4SI (vec_select:V8HI (vec_concat:V16HI
(const_vector:V8HI [
(const_int 0 [0]) repeated x8
])
(mem:V8HI (reg:DI 96) [0 *src_3(D)+0 S16 A128]))
(parallel [
(const_int 0 [0])
(const_int 8 [0x8])
(const_int 1 [0x1])
(const_int 9 [0x9])
(const_int 2 [0x2])
(const_int 10 [0xa])
(const_int 3 [0x3])
(const_int 11 [0xb])
])) 0)
(const_int 16 [0x10])))
to sign_extend of (mem:V8HI (reg:DI 96)
