josyb => that you mean is quartus doesn't compile with the same way each time when it compiles. That's why sometimes the compilation is ok and after changing a value, the compilation is not ok?
But it's strange, if the first compile is ok and after changing a value the compilation isn't ok, I return my first value and is ok. This work is verified more times.
That's why I think the compile is made following the value as follows your explanation (josyb) and so the value defines the way of compile. Is correct?
When i find my correct, I'll pray all gods for the compile uses a good way.