What's this QR for?

Question

I encountered with Ax=0, A is complex matrix, it used [U,S,V]=svd(A,0) and x=V(:,end) which makes sense.

However, it continues D=diag(abs(x)), [Q,R]=qr((AD).'), x=DQ(:,end);

What's these last operations for (all in Matlab code)?

Thank for help.