Fuchsia provides a slot relative to tp for the unsafe stack pointer.
Leave unrelated functions alone
This is way too complicated and confusing to read. Just use --check-prefix=FUCHSIA and use update_test_checks.py to generate the CHECK lines. And probably this should have a non-Fuschia test too.
And *please* add RISCV backend maintainers and regular reviewers/committers as reviewers on such patches