[pixel shader]
uniform float4 x;

float4 main() : sv_target
{
    if (x.x == 9.0f) discard;
    return x;
}

[test]
uniform 0 float4 1 2 3 4
draw quad
probe all rgba (1, 2, 3, 4)
uniform 0 float4 9 8 7 6
draw quad
probe all rgba (1, 2, 3, 4)