// Used to expose bugs in constant variable optimization,
// when variables were deemed constant not taking into
// account branches or previous dereferences of them.

uniform float mode;
float func (float c) {
    if (mode == 2.0)
        return c;
    if (mode == 3.0)
    	discard;
    if (mode == 10.0)
        c = 0.1;
    return c;
}
void main() {
    vec4 c = gl_FragCoord;
    c.x = func(c.x);
    gl_FragColor = c;
}