如何在GCC x86内联汇编中使用地址常量

int x = 10;
int y = 20;

__asm__("movl %1, %%eax; addl %2, %%eax"
        : "=a" (x)
        : "m" (x), "m" (y)
        : "%eax");

int x = 10;
int y = 20;

__asm__("movl %1, %%eax; addl %2, %%eax"
        : "=a" (x)
        : "m" (*(int*)&x), "m" (*(int*)&y)
        : "%eax");

int x = 10;
int y = 20;

__asm__("movl %1, %%eax; addl %2, %%eax"
        : "=a" (x)
        : "r" (&x), "r" (&y)
        : "%eax");