[llvm] Add extended mnemonics (PR #97571)

[Ulrich Weigand via llvm-commits]

uweigand wrote:

The CI shows failures in insn-good.s and a bunch of SystemZ LLD tests, these definitely need to be addressed.

Also, can you re-check that all mnemonics added here are also accepted by GAS?  I think at least these may not be:  nhhr, nhlr, nlhr, ohhr, ohlr, olhr, xhhr, xhlr, xlhr.   You should verify that GAS can assemble all the insn-good* files (resulting in mostly identical object files - at least the disassembly of those object files needs to match again).


https://github.com/llvm/llvm-project/pull/97571