On 2017-08-15 14:24 +0800, Xi Ruoyao wrote:
> In your code:
>
> asm(
> "addl $1,(%1)"
> : "=r"(res)
> : "rdi"(z)
> : "memory"
> );
>
> "res" is an unused output variable. So GCC just optimize it away. You
> should use "asm volatile".
And I think it's better to rewrite it:
asm( "addl $1, (%0)" :: "rdi"(z) : memory );
It would eliminate the unused variable res.
--
Xi Ruoyao <ryxi@xxxxxxxxxxxxxxxxx>
School of Aerospace Science and Technology, Xidian University
