[Bug rtl-optimization/120284] inline assembly operand constraint not comply with document

[huiba.lhb--- via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120284

--- Comment #5 from Huiba Li <huiba....@alibaba-inc.com> ---
> Marking x as an output without tieing it to another register will have
> garbage in the variable after the inline-asm. That is explicitly mentioned.

Oh, I see. 

Thanks!