https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114597
--- Comment #3 from wierton <141242068 at smail dot nju.edu.cn> ---
Thanks a lot, I have checked it out.
I'm still somewhat confused. Does the difference in compilation stem from GCC
interpreting "=m" and "=r" differently, leading it to assume that once "n.p" is
declared as an output operand without matched input declaration (eg. "=m"
expects "m", "=r" expects "r"), its value is expected to change?
```
asm("":"=m"(n.p):"r"(n.p)); // n.p is expected to change
asm("":"=r"(n.p):"r"(n.p)); // n.p can retain its value
asm("":"=m"(n.p):"m"(n.p)); // n.p can retain its value
```
Thanks in advance for any further explanation you can provide.
