[llvm] [llvm-mca] Add optional identifier field to mca::Instruction (PR #97867)

[Michael Maitland via llvm-commits]

michaelmaitland wrote:

@mshockwave added metadata to llvm-mcad but it did not have a significant impact on improving accuracy or precision. With that knowledge, I am not sure how important it is to modify upstream like this. SiFive has ripped out usage of metadata in our fork of llvm-mcad and integrated with no changes to upstream llvm.

I am curious whether @chinmaydd has a strong motivation to support metadata in llvm-mcad that would warrant us to take this change here. 

I am a supporter of making llvm-mcad work with upstream LLVM. The question remains what approach to take.

 

https://github.com/llvm/llvm-project/pull/97867