how to use noreduce

[vsreejishav82]

sir,

i want to norduce in my program. but i don't know how it works....
if i use norduce for one signal it shows another signal is combinational loop./

so how can i avoide this problem

 

[vsreejishav82]

plllllllllllllllzzzzzzzzzz

why no one is helping me plz i want to use norduce attribute in my vhdl program. how it works or how to use this i mean syntax