Hi,

This adds some known-to-work test cases from the PR.
Tested on sh-elf with
make -k check-gcc RUNTESTFLAGS="sh.exp=pr59478.c --target_board=sh-sim
\{-m2/-ml,-m2/-mb,-m2a/-mb,-m4/-ml,-m4/-mb,-m4a/-ml,-m4a/-mb}"

Committed as r227958.

Cheers,
Oleg

gcc/testsuite/ChangeLog:
	PR target/59478
	* gcc.target/sh/pr59478.c: New.