varying lowp float xx;

int func(inout float x)
{
	x = x*2.0;
	return 0;
}

void main()
{
	lowp float x = xx;

    int i = func(x); // side effects!
    
    if (x < 0.0)
        discard;

    lowp float c = 0.0;
    for (; i < 4; ++i)
        c += xx;
    gl_FragColor = vec4(c);
}