[llvm] [AMDGPU][MC] Improve error message for missing dim operand (PR #96588)

[Jun Wang via llvm-commits]

jwanggit86 wrote:

> This looks like an improvement over the status quo, but why did you choose to do this rather than replicate sp3's behavior? You should probably update [#47585](https://llvm.org/bz48241) to explain your thought process.

Please see my summary in [47585](https://github.com/llvm/llvm-project/issues/47585) where I listed 4 options. No. 2 is to mimic sp3 and to make dim optional, but colleagues raised questions about whether the sp3 default value for dim was suitable.

https://github.com/llvm/llvm-project/pull/96588