[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 #29 from Kazumoto Kojima <kkojima at gcc dot gnu.org> ---
Created attachment 33528
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33528&action=edit
A trial patch

The patch is to refrain from changing to class R0_REGS for r943.

With the above 2 patches, the remained test case failing with the ICE
in assign_by_spill is gcc.dg/pr38338.c which uses extra-ordinary
__builtin_apply_args and __builtin_apply builtins.  I can't get
what is going on that case yet.