[Bug target/63949] Aarch64 instruction combiner does not optimize subsi_sxth function as expected

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63949

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to ktkachov from comment #1)
> Confirmed. Also, I see it failing on 4.9.2 and 4.8.4 as well. Has this ever
> worked?

No I have never seen it work.