[Bug target/106038] x86_64 vectorization of ALU ops using xmm registers prematurely

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106038

--- Comment #6 from Hongtao.liu <crazylht at gmail dot com> ---

> backwards STV?

There's a pass in x86 backend called STV(scalar to vector, the pass convert
scalar instructions into vector mode when profitable), I guess "backwards STV"
means converting vector instruction back to scalar mode.