https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120284
--- Comment #7 from Huiba Li ---
> In that case you need to use "movq %1, %0" in the asm to actually copy the
> value, because the constraints don't guarantee it is the same register, it
> can very well be a different one.
> By using "0" or "+r"
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120284
--- Comment #3 from 鲁七 ---
> Note the 0 there rather than r. r in the input means any register while 0
> means it needs to match the same register as the 0th operand which in this
> case is the output operand.
Thanks for your quick response. Us
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120284
--- Comment #5 from Huiba Li ---
> 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!
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120284
Bug ID: 120284
Summary: inline assembly operand constraint not comply with
document
Product: gcc
Version: 14.2.0
Status: UNCONFIRMED
Severity: normal
