General Description: Synplify is leaving unnecessary nets unconnected after optimization, which results in numerous NGDBuild warning messages similar to the following:
WARNING:Ngdbuild:452- logical net "net" has no driver. WARNING:Ngdbuild:454- logical net "net" has no load.
Solution
The only way to avoid these warnings messages is to turn off "preserve hierarchy" in Synplify as follows:
VHDL:
library synplify; use synplify.attributes.all; : : architecture top of top is : attribute syn_netlist_hierarchy of top : architecture is false; -- Other coding
Verilog:
module top (clk, qout, a, b) /*synthesis syn_netlist_hierarchy=0 */; /* Other coding */