How to make gcc aware of arguments in embedded assembly code?

[Peng Yu via Gcc-help <gcc-help@xxxxxxxxxxx>]

Hi,

I have the following embedded assembly code which works fine without
optimization. But it fails when the optimization is enabled. How to
make gcc aware of the fact that the assembly code takes arguments?

$ cat main.c
int f(int x, int y) {
	__asm__(
			"lea (%rdi, %rsi, 1), %rax\n"
			"pop %rbp\n"
			"ret\n"
			);
}
int main() {
	return f(1, 2);
}
$ gcc main.c
$ ./a.out || echo "$?"
3
$ gcc -O3 main.c
$ ./a.out || echo "$?"
Segmentation fault
139

-- 
Regards,
Peng