[clang] [llvm] [MC] Remove UseAssemblerInfoForParsing (PR #91082)

[Fangrui Song via cfe-commits]

MaskRay wrote:

> Thanks for the additional context. My main concern is that we're undoing the consensus of [reviews.llvm.org/D45164](https://reviews.llvm.org/D45164) which if I've understood the comments properly was "There is a reasonable expectation that compiled (not assembled) code should be identical, or at least as close to the assembly output.
> 
> I'm not hugely concerned about that personally as I don't think there are any written guarantees and I come from a background of a toolchain that didn't come close to that (assembler output was disassembled from object file), however there were some strong opinions on the original change.
> 
> Do we have any strong opinions from the other reviewers?
> 
> If there is a RFC I suggest that it would be entitled something like "[RFC] Clang assembly/object equivalence for files with inline assembly". If it is worded in such a way that this is needed for the kernel and we want to check for community input then if there is no response then we can go ahead.

Thanks for the suggestion. I created https://discourse.llvm.org/t/rfc-clang-assembly-object-equivalence-for-files-with-inline-assembly/78841

https://github.com/llvm/llvm-project/pull/91082