GLSL for loop with variable condition-expression


am I right that in GLSL a for loop should not contain
a variable as part of the condition-expression?

I read something about the driver is unrolling the loop
and cant do this because he does not know the value of
the variable in the condition-expression at compile time.


Mhm maybe this applied only to old GLSL versions?
It seems to work with a variable in GLSL 1.50.