I understand that the expression x = m*a+d is most efficiently written as x = mad(m,a,d) because at the assembly level only one instruction is needed rather than a multiply and add separately. My question regards optimally writing this expression: x += m*a. Should this be written as x = mad(m,a,x) or x += m*a? The difference is too subtle to profile but I'm wondering if anyone can see the difference at the assembly level. (I don't know how to view the assembly code.)
mad regx, regm, rega, regx