thanks Thomas Stanka! But...
In my code I have instantiated a GL Buffer (is a fast clock). But in the synthesis: the log say...
Automatic dissolve during optimization of view:work.w_r9(w_r9) of GL2(GL)
then, others signals with highest fanout promoted to global buffer. This synthesis is made with Synplify.
I don=B4t know how change this automatic options.