// gcc -S -O0 
	.file	"x.cpp"
	.text
	.globl	main
	.type	main, @function
main:
.LFB0:
	.cfi_startproc
	pushq	%rbp
	.cfi_def_cfa_offset 16
	.cfi_offset 6, -16
	movq	%rsp, %rbp
	.cfi_def_cfa_register 6
	movl	$10, -20(%rbp)
	movl	$20, -4(%rbp)
	leaq	-20(%rbp), %rax
	movq	%rax, -16(%rbp)
	movq	-16(%rbp), %rax
	movl	-4(%rbp), %edx
	movl	%edx, (%rax)
	movl	$0, %eax
	popq	%rbp
	.cfi_def_cfa 7, 8
	ret
	.cfi_endproc
.LFE0:
	.size	main, .-main
	.globl	_Z1rv
	.type	_Z1rv, @function
_Z1rv:
.LFB1:
	.cfi_startproc
	pushq	%rbp
	.cfi_def_cfa_offset 16
	.cfi_offset 6, -16
	movq	%rsp, %rbp
	.cfi_def_cfa_register 6
	movl	$0, -20(%rbp)
	movl	$0, -4(%rbp)
	leaq	-20(%rbp), %rax
	movq	%rax, -16(%rbp)
	movq	-16(%rbp), %rax
	movl	-4(%rbp), %edx
	movl	%edx, (%rax)
	nop
	popq	%rbp
	.cfi_def_cfa 7, 8
	ret
	.cfi_endproc
.LFE1:
	.size	_Z1rv, .-_Z1rv
	.ident	"GCC: (SUSE Linux) 6.2.1 20160830 [gcc-6-branch revision 239856]"
	.section	.note.GNU-stack,"",@progbits

// source
int main() {
    int a = 10;
    int b = 20;
    int *x = &a;
    *x = b;

    return 0;
}

void r() {
    int a = 0;
    int b = 0;
    int &c = a;
    c = b;
}