Such an expression where value of a variable is being modified more than once is dependent upon the compiler or not?

Question

for eg: (++x) *(++x) when x=5 will give different results for different compilers or not?

Answer 1

It depends upon the compiler )
and feel free to do not prove me wrong .

Answer 2

This should always have the same result. Mathematcly your term is (x+1) * (x+2) which with x =5 should always be 42. But feel free to prove me wrong,