resolve https://github.com/rust-lang/stdsimd/pull/8#discussion_r495582339
resolve https://github.com/rust-lang/stdsimd/pull/8#discussion_r495582339

graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust