[Bug middle-end/126167] LRA / SH: Improve on R0 spill failures

[olegendo at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126167

--- Comment #1 from Oleg Endo <olegendo at gcc dot gnu.org> ---
The changes that I have for this also fix PR 126431, so there's that.