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

[Bill Wendling via llvm-commits]

bwendling wrote:

> Does this patch handle both "=rm" and "rm"?
> 
> The patched clang (with `clang -O2 a.c`) reports `a.c:3:21: error: invalid operand for instruction` for the example
> 
> ```
> asm __volatile__ ("pushf ; popq %0" : "=rm" (x));
> ```

Could you give the full function that produces this error?

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