[Bug target/122558] RISC-V: inefficient lmul selection for 4-element vector operations

[chenzhongyao.hit at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122558

--- Comment #3 from Zhongyao Chen <chenzhongyao.hit at gmail dot com> ---
Created attachment 62759
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62759&action=edit
proposed patch

This patch tested and works, please take a look.