[GiNaC-list] sqrt(x*x) Simplification

Hi, I am wondering how one can get GiNaC to expand the expression sqrt(x*x) to x (where symbol x("x")), under the assumption than x is real. Does GiNaC have a function to perform such an expansion? I looked though the reference PDF file but could not find anything analogous to Mathematica's PowerExpand. When one can be sure that complex numbers are not involved it is often quite a nice simplification. Regards, Freddie.