[clang] [llvm] [Clang][inlineasm] Add special support for "rm" output constraints (PR #92040)

[Bill Wendling via cfe-commits]

bwendling wrote:

With this newest commit, I believe that the changes can be reviewed. I've removed the "x86-only" aspect. I've kept the 'InlineAsmPrepare' pass because I think that it can be expanded in the future to improve inline asm even more (there are still incompatibilities between Clang's and GCC's handling of inline asm).

I'm working on comprehensive testing files, which is a bit harder than it appears. But it's coming soon.

PTAL

https://github.com/llvm/llvm-project/pull/92040