sum without carry out

[elme2]

I'm trying to implement a 8bit adder with a,b :input (7:0).
c<= ('0'&a)+('0'&b) to include the carry out, but when i synthesize it appears a message including a 8bit carry out.

My design has a lot of this procedure, so i need to eliminate this carry out. ¿Is there a function who makes the sum whithout place a carry out?. I tried to implement it, but the final design use more resources than the simply adder.

Thanks