[Bug target/55212] [SH] Switch from IRA to LRA

[kkojima at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55212

--- Comment #27 from Kazumoto Kojima <kkojima at gcc dot gnu.org> ---
Created attachment 33526
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33526&action=edit
A trial patch

It disables equiv substitution when the equiv includes some reg
assigned to a small register class.  I hope that it makes the issue
a bit clearer, even if it doesn't the right thing.