[clang] [llvm] [inlineasm] Add special support for "rm" inline asm constraints (PR #181973)

[Bill Wendling via cfe-commits]

bwendling wrote:

@nickdesaulniers @nikic I created https://github.com/llvm/llvm-project/pull/195104 to perform refactoring of the `SelectionDAGBuilder::visitInlineAsm()` method. It's a precursor to the "simplified" method mentioned above (https://github.com/llvm/llvm-project/pull/181973#discussion_r3060997311). It will make reviews much easier. However, I think this change should go in regardless of whether or not you agree with the ultimate method chosen.

https://github.com/llvm/llvm-project/pull/181973