* LABEL is important to give a better diagnostic in case a check pattern fails
* Some NOT negative patterns are not effective. NEXT is useful to ensure
a code sequence has the desired instructions and report a better
diagnostic if something goes off.
* Since the ABI says the first parameter is in RDI. Replacing the
pattern `[[REG16:.*]]` with `RDI` should not cause maintenance burden.
Since the test is pretty mechanical, just use update_llc_test_checks.py
to re-generate it. Most functions can use `nounwind` to avoid CFI
directives.
Reviewed By: kstoimenov, vitalybuka
Differential Revision: https://reviews.llvm.org/D118864
f3a66ec0bd