[Bug target/67391] [SH] Convert clrt addc to normal add insn

[kkojima at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67391

--- Comment #5 from Kazumoto Kojima <kkojima at gcc dot gnu.org> ---
(In reply to Oleg Endo from comment #4)
> I've just checked, the code is also present in GCC 5.  Because of the funny
> side effects even with LRA disabled (this PR) I'd like to backport this to
> the GCC 5 branch, too.

Yes, this is clearly a 5/6 regression.  My test has passed C and C++ part
with no new failures.  I'll report back when test completed.