[llvm-branch-commits] [AMDGPU] Enable aliases in InstPrinter (PR #171265)

[Alexander Richardson via llvm-branch-commits]

https://github.com/arichardson created https://github.com/llvm/llvm-project/pull/171265

After the latest change to tablegen, we now handle `RegClassByHwMode`
correctly in the alias pattern output of -gen-asm-writer, so we can
enable it for AMDGPU. Previously, `#define PRINT_ALIAS_INSTR` caused
compilation failures due to tablegen referencing *RegClassID variables
that do not exist for `RegClassByHwMode`.

This causes a large number of test failures (380) so I just put this
up as a draft pull request to see if it is desirable. It looks like the
one test I updated uses wrong mnemonics so probably needs more work.